SPACE GASS 12.5 HELP MANUAL

SPACE GASS 12 User Manual

Table of Contents Introduction Introduction How to use this manual Printing this manual Legal notice Hardware requirements Product support Hardware locks and insurance New features

1 1 2 5 6 9 10 11 12

Installation and Configuration Installation and configuration Installing SPACE GASS Configuring SPACE GASS Folders and files Text formatting General configuration Graphics scale calibration Graphics colors General colors Problem size limits Renderer configuration Customizing toolbars Customizing property panels The SPACE GASS utility tool

23 23 24 25 26 28 29 32 33 34 35 36 42 45 47

Getting Started Getting started Starting SPACE GASS Command line options The main SPACE GASS window The status line Using the mouse Dialogue boxes Data entry Managing job files Starting a new job Opening a job Merging jobs Saving a job Deleting a job Cleaning up a job Running a macro Running a script Job status Shortcuts

49 49 50 51 53 55 57 58 60 62 63 64 65 66 67 68 69 70 73 74

Input Methods Input methods

77 77

iii

SPACE GASS 12 User Manual Linking to Other Programs Linking to other programs CIMSteel/2 Step, IFC Step and Revit links Import links Export links Special Revit Structure links DXF links Importing DXF files Exporting DXF files

79 79 81 84 88 91 94 95 96

Modelling the Structure Modelling the structure Coordinate systems Sign conventions Ill-conditioning and instabilities

101 101 102 107 111

Project Data Project data Units Job details and attachments Node data Member data Plate data Node restraint data Section property data Standard section libraries Shape builder Flipping a section Column and beam Tee sections Angle sections Material property data Master-slave constraint data Member offset data Node load data Prescribed node displacement data Member concentrated load data Member distributed force data Member distributed torsion data Thermal load data Member prestress data Plate pressure data Self weight data Combination load case data Load case title data Lumped mass data Spectral load data Spectral curve editor Importing a spectral curve Area load data Sea load data Moving load data

113 113 114 116 118 119 124 129 132 135 136 143 144 145 146 148 154 156 157 158 160 162 164 165 167 168 169 171 172 174 177 178 179 181 182

Text File Input

185

iv

Table of Contents Text file input Text file format Initiator Headings text Nodes text Members text Plates text Node restraints text Section properties text Material properties text Master-slave constraints text Member offset text Node loads text Prescribed node displacements text Member concentrated loads text Member distributed forces text Member distributed torsions text Thermal loads text Member prestress loads text Plate pressure loads text Self weight text Combination load cases text Load case titles text Lumped masses text Spectral loads text Steel member design text Terminator Text file errors Text file example

185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 212 213 216

Structure Wizard Structure wizard

219 219

Portal Frame Builder Portal frame builder Portal frame geometry Portal frame extra data Portal frame sections and materials Portal frame loads Portal frame load cases Portal frame design Portal frame assumptions

221 221 223 226 229 230 234 235 236

Datasheet Input Datasheet input Using datasheets

237 237 238

Graphical Input Graphical overview The renderer The traditional graphics window Align members Align plate axes

245 245 246 269 276 278

v

SPACE GASS 12 User Manual Arc generation Area loads Attach Attachment and alignment methods Bends generation Combination load cases Connect Connectivity check Coordinates Copy Copy member loads Copy member properties Copy node loads Copy node properties Copy plate loads Copy plate properties Delete Draw Extend Extrude Filters Find Grid Gridlines Infotips Intersect Keyboard positioning of points Load case titles Lumped masses Managing load cases Master-slave constraints Material properties Measurements and dimensions Member concentrated loads Member distributed forces Member distributed torsions Member offsets Member prestress loads Member properties Mesh Mirror Move Move intermediate nodes Moving loads Multiple viewports Node loads Node properties Node restraints Notes Ortho Pan Plane Plate pressure loads Plate properties Prescribed node displacements vi

279 280 283 285 289 290 293 294 295 296 299 300 301 302 303 304 305 306 309 310 312 314 317 319 321 322 323 325 326 328 330 331 332 334 336 338 340 341 343 346 348 349 351 352 370 372 374 377 378 380 381 382 384 386 389

Table of Contents Property panels Query analysis results Query frame Query steel member design results Redraw Remove crossed member nodes Remove intermediate nodes Renumber Repeat last command Reverse member direction Reverse plate direction Rotate Scale Scales Sea Loads Section properties Select all Selection methods Self weight Snap Spectral loads Static load to mass conversion Stretch Subdivide Taper plates Taper/haunch generation Textures Thermal loads Transparency Varying plate pressure loads View buckling mode shapes View diagrams View dynamic mode shapes View envelope View global origin View labelling and annotation Load case titles viewer View local axes View manager View member origins View node / member / plate properties View nodes / members / plates View plate contours View results in local XY or XZ plane View steel member design groups View steel member design results View steel member flange restraints View steel member top flanges Viewpoint Views Zoom Analysis Analysis

391 395 397 398 399 400 401 402 404 405 406 407 408 409 411 418 419 420 422 423 425 426 427 428 429 431 433 435 437 439 443 444 445 446 447 448 451 453 454 455 456 457 458 460 461 463 466 467 468 471 473 475 475

vii

SPACE GASS 12 User Manual Static analysis Static analysis Displacements, actions and reactions P-D effect P-d effect Tension-only and compression-only effects Cable members Non-linear analysis procedure Static analysis buckling The wavefront optimizer The wavefront analysis method A quick frontwidth calculation method The wavefront method in more detail Running a static analysis Static analysis results Buckling analysis Buckling analysis Buckling effective lengths Special buckling considerations Running a buckling analysis Buckling analysis results Dynamic frequency analysis Dynamic frequency analysis Modelling considerations Running a dynamic frequency analysis Dynamic frequency analysis results Dynamic spectral response analysis Dynamic spectral response analysis Running a dynamic spectral response analysis Dynamic spectral response procedure Dynamic spectral response analysis results Analysis warnings and errors Steel Member Design Steel member design Steel member input methods Auto-create steel members Steel member input form Steel member input datasheet Copy steel member properties Steel member design data Steel member design sign conventions Member groups Flange restraints Column and beam Tees Running a steel member design Updating analysis member sizes Serviceability check The steel member design/check process Design groups and intermediate stations Design segments Section check Member check Critical flange

viii

476 476 478 479 480 481 482 484 485 486 491 492 493 494 501 502 502 504 506 508 512 514 514 515 516 521 522 522 524 528 529 531 535 535 537 538 543 545 546 547 557 558 562 568 569 575 576 577 578 579 580 581 582

Table of Contents Effective flange restraints Twist factor Load height factor Lateral rotation factor End moment ratios and other factors Eccentric effects for compression members Eccentric effects for tension members The code check Steel member design results Steel member design/check assumptions BS5950-1:2000 code specific items Hong Kong CP2011 code specific items AISC 360-10 code specific items Eurocode EN 1993-1-1:2005 code specific items AS/NZS 4600:2005 code specific items IS800 code specific items Steel member design/check errors

583 585 586 587 589 590 591 592 593 595 600 605 607 612 615 619 620

Steel Connection Design Steel connection design Creating and editing connections The connection manager Design considerations Connection reports Connection preferences

623 623 625 636 641 643 645

Concrete Beam Design Concrete beam design Creating and editing concrete beams The concrete manager Concrete beam preferences AS3600 2009 code specific items for beams IS456 2000 code specific items for beams

647 647 649 664 669 671 675

Concrete Column Design Concrete column design Creating and editing concrete columns The concrete manager Concrete column preferences AS3600 2009 code specific items for columns IS456 2000 code specific items for columns

677 677 679 693 698 699 702

Output Output Page setup View text report Print preview Print text report Print graphics The status report

705 705 709 712 713 715 716 717

Standard Libraries Standard libraries

719 719 ix

SPACE GASS 12 User Manual The library editor

721

Importing and exporting

723

Importing old libraries Section libraries Material libraries Bolt libraries Plate libraries Weld libraries Reinforcing bar libraries Spectral curve libraries Vehicle libraries

724 725 727 728 729 730 731 732 733

Portal Frame Analysis Portal frame analysis Geometry and loads Method of input Analysis procedure Analysis results Graphical output Analysis input report Static analysis report (itemised) Static analysis report (enveloped) Bill of materials report Dynamic frequency analysis report Dynamic spectral response analysis report Buckling analysis report

735 735 736 740 741 742 743 747 755 766 773 774 775 776

Portal Frame Member Design Portal frame member design Member design results Steel member design report

779 779 783 784

Portal Frame Connection Design Portal frame connection design Connection design results

787 787 789

Cable Analysis Cable analysis Method of input Analysis procedure Analysis results

805 805 806 807 808

Converting Old Jobs Converting old jobs

815 815

Bibliography Bibliography

817 817

Index

821

x

Introduction Introduction SPACE GASS 12.5 77th Edition, April 2016 SPACE GASS is a general purpose structural analysis and design program for 2D and 3D frames, trusses, grillages, beams and plates. It includes a full complement of features that make it suitable for any job from small beams, trusses and portal frames to large high rise buildings, towers and bridges. To see the new features recently added, refer to New features. Its emphasis on graphics means that you easily see the status of your model at all times. In fact, the extensive range of graphical editing tools allow you to input your model or make changes entirely within the graphical editor. Of course, if you prefer to work with datasheets or other methods of input then they are available too. A structure wizard automatically generates the initial data for many typical structures which you can then manipulate to create the exact model you want. State of the art solvers for linear and non-linear static analysis, dynamic analysis and buckling analysis are available. Steel and concrete design modules for various international codes of practice are also available. Graphical and text reports can be generated for any parts of the structural model. Comprehensive filters that can be defined graphically allow you to customize your graphical views and output reports to include just want you want to see. Although SPACE GASS is a comprehensive program with many advanced features, its logical menu structure, toolbars and graphical emphasis makes it easy to learn and use, even for first time users. If you have questions or need help then you will probably find the answers in this manual.

1


How to use this manual Illustrated as follows is an example of each of the three outline styles used in this manual. These styles are designed to draw your attention to information in one of three ways: as a hint, an important note or general note. Hints are non-essential, but useful, pieces of information which will improve your understanding of the program. Hints sometimes identify a special way of doing something and are typically quite specific. Important notes should be carefully read and understood. They outline information that is vital to the effective use of the software. Notes identify articles of information which are meant as an aside to aid your understanding of SPACE GASS. Some notes are quite general in nature and do not give reference to a specific procedure. Notes may also serve to draw your attention to specific interpretation. HINTS This is an example of the SPACE GASS HINTS style and icon. IMPORTANT NOTES ! IMPORTANT NOTE ! This is an example of the SPACE GASS important note style and icon. NOTES

This is an example of the SPACE GASS NOTES style and icon. Following is a brief overview of each section in the manual. Chapter 1 "Installation and Configuration" Deals with the installation and configuration of SPACE GASS. Once the software is installed and running correctly, you should not have to refer to this chapter again. Chapter 2 "Getting Started" If you are new to frame analysis programs or Windows programs in general, then you should read this chapter before attempting to run a job. It provides very good basic information that you will need to know about the operation of SPACE GASS. Chapter 3 "Input Methods" Explains the four main methods of inputting and editing your model. Chapter 4 "Linking to Other Programs" Describes how data can be transferred between SPACE GASS and other structural analysis, CAD and building management programs.

2

Introduction Chapter 5 "Modelling the Structure" Discusses the basics of how you can model a structure with SPACE GASS and includes information on nodes, members, restraints, coordinate systems, sign conventions, etc. Chapter 6 "Project Data" Gives a detailed description of each type of data that can be used in the frame analysis part of the model. Data for steel and concrete design is not included (see later chapters). This chapter deals only with the data itself, and leaves the discussion of the numerous methods that you can use to input the data to later chapters. Chapter 7 "Text File Input" Describes the format of standard SPACE GASS text files. This is one of the five methods of data entry. You can type your data into a standard text file and then import it into SPACE GASS. Standard text files can also be used as an alternative for permanent storage of data. Chapter 8 "Structure Wizard" Another method of input involves selecting from a number of standard structures, answering a few simple questions about the structure selected, and then having the structure wizard generate all of the frame data for you. Any of the other data entry methods can be used to modify the data after it has been generated using this method. Chapter 9 "Portal Frame Builder" Described in detail the portal frame builder and how it can be used to generate the complete model of a portal frame building including the full structure, loads (including wind loads) and design data. Chapter 10 "Datasheet Input" Is a modified form of spreadsheet input which allows you to input or edit any parts of the frame data or steel design data. Along with graphical input, this is probably one of the most useful and versatile methods of data entry. Chapter 11 "Graphical Input" Covers all of the graphics facilities, including those in the renderer. This includes graphical structure input, graphical load input, graphical steel design input, connection drawing detail, graphical output of loading, displacement, bending moment, shear force, stress, axial force and animated mode shape diagrams. Full descriptions are also given for the many commands associated with drawing, moving, copying, rotating, mirroring, erasing, zooming, panning, scaling, coordinate systems, changing the viewpoint, labelling, querying diagrams, viewing the rendered model, hidden line removal, renumbering, etc. Chapter 12 "Analysis" The static, dynamic and buckling analysis modules, together with their options and control parameters are fully described here. Chapter 13 "Steel Member Design" Details the use of the steel member design module. Please pay particular attention to the assumptions listed near the end. Chapter 14 "Steel Connection Design" Details the use of the steel connection design module. Chapter 15 "Concrete Column Design" Details the use of the reinforced concrete column design module. Please pay particular attention to the assumptions listed near the end.

3

SPACE GASS 12 User Manual Chapter 16 "Output" Describes the types of output reports and graphics hardcopies that can be obtained and the options that are available for sorting, formatting, enveloping, positioning on the page, etc. Chapter 17 "Standard Libraries" SPACE GASS is supplied with a number of standard section, material, bolt, plate and weld libraries. This chapter provides a complete guide on how you can customise any of these libraries, or create your own section libraries. Appendix A "Portal Frame Analysis" Presents a detailed report on the analysis of a typical steel portal frame. Full discussions regarding the input data and the decisions involved in producing it are included, together with complete printouts of the analysis input and output reports. Appendix B "Portal Frame Member Design" Presents a detailed report on the member design for the steel portal frame analysed in appendix B. It includes a discussion on how the steel members are being modelled, together with complete printouts of the member design input and output reports. Appendix C "Portal Frame Connection Design" Presents a detailed report on the connection design for the steel portal frame analysed in appendix B. It includes a discussion on how the steel connections are being modelled, together with complete printouts of the connection design input and output reports. Appendix D "Cable Analysis" Presents a worked example demonstrating the input and analysis of a 30m tall, guyed mast. The catenary cable equations are used to calculate the axial force in a nominal guy member, this is then compared to the result obtained from SPACE GASS. Appendix E "Converting Old Jobs" Explains how you can convert data files that were produced with SPACE GASS v1, v2 or v3 for loading into the latest version. Note that data files produced with SPACE GASS 4 or later are automatically converted into the latest format when they are opened. Appendix F "Bibliography" A list of references.

4

Introduction

Printing this manual This manual is also supplied in an Adobe PDF format that is ideal for printing. You can get to it by looking for sgwin.pdf in your SPACE GASS program folder (usually "c:\Program files (x86)\SPACE GASS 12").

5


Legal notice End User License Agreement Notice to Licensee: This End User License Agreement (the "Agreement") is a legal agreement between you and I.T.S. Integrated Technical Software Pty Ltd (ACN 086 605 567) ("ITS"), a registered company under the Corporations Law of the State of Victoria, Australia. BY USING THIS PRODUCT, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS OF THIS AGREEMENT. If you do not agree to all the terms and conditions of this Agreement or if you do not have the authority to agree to all the terms and conditions of this Agreement on behalf of the licensee then you MUST NOT USE THE PRODUCT. Provided the Product has not been used and is not a loan, student or evaluation version, you may return it to your place of purchase for a full refund. 1. Definitions. For the purposes of this Agreement, the following terms shall have the following meanings: 1.1 "Product" shall mean and include the SPACE GASS software, updates, CDs, computer disks, Security Devices, help files, reference manual or other instructions, technical support or any other software, items or information of any kind provided by ITS or obtained from the www.spacegass.com web site. 1.2 "Software" shall mean all software included in the Product. 1.3 "Security Devices" shall mean and include hardware or software that limits the number of users that may operate the Software simultaneously, or imposes an Expiry Date beyond which the Software cannot be used, or prevents certain parts of the Software from being used. 1.4 "Expiry Date" shall mean the date imposed by any Security Devices beyond which the Software cannot be used. 1.5 "ITS" includes its employees, agents and suppliers. 2. License. The Product is protected by copyright laws and international copyright treaties, as well as other intellectual property laws and treaties. The Product is licensed, not sold. 2.1 Grant of License. Subject to the terms and conditions of this Agreement, ITS grants to you a non-exclusive license to use the Product during the term of this Agreement. 2.2 User Limit. The Software may be installed on an unlimited number of computers, however the maximum number of users operating it simultaneously may not exceed the user limit imposed by the Security Devices. 2.3 Reference Manual. You may make such copies of the reference manual as are reasonably necessary for your use of the Product by the permitted number of simultaneous users, but you may not make copies of the reference manual for any other purpose without the prior written consent of ITS. 3. Ownership; Proprietary Rights. ITS shall at all times be the owner of and have all rights to the Product, and all intellectual property associated therewith, including but not limited to patents, copyrights, trade names and marks, domain names, and trade secrets related thereto. The Product is protected by copyright laws and international treaty provisions. Nothing herein 6

Introduction shall cause or imply a sale, license or transfer of any intellectual property rights of ITS to you or to any third party, except as expressly set forth herein. You may not reverse engineer, decompile, disassemble, or otherwise attempt to discover the source code of the Software. You may not attempt to reverse engineer, duplicate or bypass any Security Devices. 4. Disclaimers. ITS makes no warranties or representations as to the Product to you or to any other party. To the extent permitted by applicable law, all implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose, are hereby disclaimed. 5. Limitation of Liability. To the maximum extent permitted by applicable law, in no event shall ITS be liable for any punitive, exemplary, consequential, indirect, incidental, or special damages arising from or related to the use of the Product by any party, including without limitation damages arising from loss of data, loss of revenue or profits or failure to realize savings or other benefits, even if ITS has been advised of or should be aware of the possibility of such damages. In the event of any defect in the Product ITS may, at its option; i. ii. iii. iv.

replace the Product or supply its equivalent; repair the Product; pay for the cost of replacing the Product or of acquiring its equivalent; or pay for the cost of having the error in the Product rectified.

To the extent that the Product involves providing a service, in the event of any error or defect in the provision of that service ITS may, at its option; i. ii.

supply the service again; or pay for the cost of having the service supplied again.

Because some states and jurisdictions do not allow the exclusion or limitation of liability, the above limitation may not apply to you. 6. Indemnification. You, at your sole expense, will defend, indemnify and hold ITS harmless from and with respect to any loss or damage (including reasonable attorneys’ fees and costs) incurred in connection with, any suit or proceeding brought by a third party against ITS insofar as such suit or proceeding shall be based upon (i) any claim arising out of or relating to your use of the Product except where such claim alleges that the Software infringes or constitutes wrongful use of any copyright, trade secret, patent or trade mark of any third party; or (ii) any claim arising out of or relating to any act or omission by you. You will pay any damages and costs assessed against ITS (or paid or payable by ITS pursuant to a settlement agreement) in connection with such a suit or proceeding. 7. Changes to the Product. ITS may change the Product from time to time without notice to you and shall not be under any obligation to provide you with any notification of such change. 8. Non-Transferability. You may not rent, lease, sub-license, lend or transfer the Product to another person or legal entity without the prior written consent of ITS. 9. Term and Termination. The term of this Agreement shall commence on the date that you install or use the Product and shall continue (unless earlier terminated as provided herein) until the Expiry Date, or in perpetuity if no Expiry Date is imposed. Without prejudice to any other rights, ITS may terminate this Agreement at any time if you fail to comply with its terms and conditions. Upon termination of this Agreement for any reason whatsoever, you shall cease all use of the Product and remove all copies of the Software from your computers.

7


10. General. 10.1 Assignment. You may not assign or transfer this Agreement or any of your rights, duties or obligations hereunder and this Agreement may not be involuntarily assigned or assigned by operation of law, without the prior written consent of ITS, which consent may be granted or withheld by ITS in its sole discretion. 10.2 Severability. Each provision of this Agreement is intended to be severable. If any covenant, condition or other provision contained in this Agreement is held to be invalid or illegal by any court of competent jurisdiction, such provision shall be deemed severable from the remainder of the Agreement and shall in no way affect, impair or invalidate any other covenant, condition or other provision contained in this Agreement. If such covenant, condition or other provision shall be deemed invalid due to its scope or breadth, such covenant, condition or other provision shall be deemed valid to the extent of the scope or breadth permitted by law. 10.3 Governing Law. You agree that the use of the Product by you shall be governed by the laws of the State of Victoria and the Commonwealth of Australia, and you consent to the non-exclusive jurisdiction of the courts of that State and the Commonwealth. 10.4 Attorneys’ Fees. If any legal action is brought arising out of or relating to this Agreement, the prevailing party shall be entitled to receive its reasonable attorneys’ fees and court costs in addition to any other relief it may be entitled. 10.5 Entire Agreement. This Agreement is the complete and exclusive statement of the agreement of the parties hereto with respect to the subject matter hereof, and supersedes all prior and concurrent agreements, promises, proposals, representations and warranties, oral or written, with respect to the subject matter hereof.

8

Introduction

Hardware requirements   

Windows 7, 8 or 10 (Windows 10, 64-bit preferred). Intel or AMD CPU (Intel multi-core preferred). Any modern graphics card with at least 2Gb RAM (NVIDIA preferred). For more detailed information, including tips on how to get the maximum speed out of SPACE GASS, refer to www.spacegass.com/hardware.

9


Product support Product support includes:     

Notification of any program modifications or enhancements as they become available. Update facility for those users wishing to upgrade to the latest version. Replacement of any software which is found to be defective through no fault of the user or which does not conform to the general published function of the software. Telephone, facsimile and email support by I.T.S. or an authorised dealer. Comprehensive Internet web site providing latest information, drivers, updates, libraries, etc. for all registered SPACE GASS users.

I.T.S. reserves the right to charge for telephone, facsimile or email support.

10

Introduction

Hardware locks and insurance SPACE GASS is sometimes supplied with a hardware lock that must be inserted into the parallel or USB port before the software will run. If the hardware lock is faulty or becomes damaged or destroyed, it can be replaced for a nominal fee provided that a remnant of the lock showing a valid serial number can be produced proving that it is a genuine SPACE GASS hardware lock. The hardware lock cannot be replaced for a nominal fee if it is lost or stolen and, for this reason, it is recommended that the user insure the software package and hardware lock for the full current market value of the software.

11


New features The key new features added in SPACE GASS since v10 are as follows. Note that minor new features, enhancements and bug fixes are not listed here. Version 12.50 This is a major new version containing a significant number of enhancements and new features. SPACE GASS now also supports hardware acceleration in all modern graphics cards. Previously this was restricted to some NVIDIA graphics cards. For more information on this and how to optimize SPACE GASS for maximum performance refer to www.spacegass.com/hardware. Version 12.27 Includes a new moving loads tool that allows for stationary and moving loads in the form of vehicles, pressure patches and line loads. Loads can now be applied to plates as well as members, plus a proximity distance setting lets you model multi-level roadways with different loads on each level. Added support for IS1893 to the spectral analysis module. Added support for IS800 seismic checks (IS800 chapter 12) to the steel member design module. Version 12.26 Adopted a less conservative approach when calculating m for segments unrestrained at one end with steel member design in accordance with AS4100 and NZS3404. Version 12.25 Added copy/paste and import/export facilities to the filter management form. Version 12.24 A new reinforced concrete column design module has been added. Version 12.23 Support for Revit 2016 has been added. Version 12.20 This is a semi-major upgrade that includes many changes, enhancements and fixes. It is also the first version that has all of the tools of the traditional SPACE GASS window now available in the renderer (along with many new tools that are only available in the renderer). A new reinforced concrete beam design module has been added. Tools for querying and viewing steel member design results have been added to the renderer. You can also label the steel member number, load factor and governing load case on each steel member in the model.

12

Introduction

A load case title column has been added to the combination load cases datasheet. Seismic checks in accordance with chapter 12 of NZS3404 have been added to the steel member design module. The clauses checked are table 12.4(1), table 12.4(3), 12.4.1.2, 12.5.2, 12.5.3.1, table 12.5, 12.7.2.1, 12.8.3.1(a), 12.8.3.1(b), 12.8.3.1(c) and 12.10.3.1. Version 12.00 This is a major upgrade containing many new features and substantial performance improvements, especially in the analysis solvers and graphics engine. It also makes the renderer the main interface for the program. Introduced a new "Paradise" solver for the static, buckling and dynamic frequency analysis modules. It is a sparse matrix solver that fully utilizes the parallel processing capabilities of modern multi-core CPUs. The new solver is usually between 10 and 100 times faster than SPACE GASS 11. The most dramatic speed savings occur with jobs that have a large matrix frontwidth and lots of load cases. The renderer graphics now fully utilizes the parallel processors on the graphics card rather than doing the graphics calculations on the main CPU. This means that deflection diagrams, bending moment diagrams, shear force diagrams, etc. can be scaled up and down smoothly regardless of the size of the job, even in fully rendered 3D mode. The renderer has been given a major overhaul with a new user interface that now has almost all of the functionality of the traditional SPACE GASS window. This means that you can do everything in the renderer without constantly having to switch back to the traditional SPACE GASS window. The new functionality in the renderer includes:               

New user interface that can be configured with different skins and user defined layouts. Substantial performance increases and no annoying delays or pauses. Opening and saving of jobs. Generating reports. Structure wizards. Datasheets. Node, member and plate drawing and editing tools. Loading input and editing tools. Filtering. Scaling. Static, buckling and dynamic analysis. Steel and concrete design. Display of all analysis result diagrams such as deflections, moments, contours, etc. Ability to show fully rendered deflections rather than just wireframe. Animated mode shapes.

Version 11.09 Released an all new Steel Connection Design module for AS4100 that complies with the latest ASI design guides. Released a new Steel Member Design module for AS4600 that works with the cold formed sections from manufacturer including Lysaght, Stramit, Duragal and others. Supported sections include Cees, Zeds, angles, tophats, channels, back-to-back Cees, CHSs, SHSs and

13

SPACE GASS 12 User Manual RHSs. New cold formed section libraries for Lysaght, Stramit and Duragal have also been included. The Portal frame builder now automatically creates all of the main connections in the building. They can then be used in the steel connection design module. Allow a steel member design to be performed via a script file with the user being able to control the design groups, sections properties and load cases considered. Allow exporting of steel member design/check summaries to a text file or MSExcel/Access/Word file. Version 11.08 Various new script commands have been added that allow you to have more control over importing/exporting and analysis. You can also pause the script to see what stage it is up to at any point. Version 11.05 Released a Portal Frame Builder module for the modelling of portal frame buildings in SPACE GASS. It generates the full structural model plus dead loads, live loads, wind loads and steel member design data. The module supports gable (symmetrical and asymmetrical) and monoslope roofs, overhangs, knee braces, haunches, fly bracing, uneven frame spacings, openings, roof/wall bracing and end wall props. Wind loads are generated in accordance with AS/NZS 1170.2:2011 for all regions in Australia and New Zealand. Version 11.01 Released a Sea Load module for the calculation of wave, current, marine growth and buoyancy loads on submerged structures in marine and offshore environments. Version 11.00 This is a major new version that includes a new 3D renderer with full editing capabilities. Of course you can still edit your model in the traditional SPACE GASS window, however the editing tools in the renderer are generally more advanced and offer additional features over the traditional editing tools. Some of the load input tools, design data tools and analysis results diagrams are not yet available in the renderer, however they will be added soon. Member force and moment envelope reports can now be limited to the maximum and minimum values taken from just one end of the members rather than from both ends. The analysis engine has also had a major make-over with finite and large displacement theory added, plus options for secant or tangent matrix solutions, residual or full loading, and residual convergence criteria. An "Auto" optimizer setting has also been added that senses the most efficient optimization method before the main analysis calculations begin. It removes the necessity for you to manually use trial and error methods to find the best optimization setting. The standard libraries have been completely re-designed allowing non-standard and built-up sections to be saved. A new shape builder, moving loads generator with animated moving loads, and area loads generator have also been added. 14

Introduction

Other major new features include on-screen notes, job attachments, dimensions, load combinations grid, load case titles viewer, measure tool, textures, gridlines, view selector, customizable toolbars and multiple undo/redo steps. The major new features of SPACE GASS 11 are listed in more detail below: 

A new renderer with full editing capabilities.



A new shape builder with shape dragging, snapping, stacking, alignment and copy/paste. Shapes can now be specified as voids to easily model holes in your sections. New standard shapes have also been added for polygons, polytubes, triangles, Cees, Zeds, tophats and schifflerized angles. Line shapes that allow you to specify a line thickness and a series of points have also been added. You can even show the dimensions of your sections graphically in the new shape builder.



On-screen notes that can be positioned anywhere on or near your model or attached to nodes, members or plates.



Dimensions that can be added to your model or to individual members or plates.



A measure tool that lets you determine the actual length, component lengths and angles between any two points.



An attachment tool that you can use to attach external documents, spreadsheets, drawings or any other files to your SPACE GASS job and embed them into the job file.



Important new drawing aids now let you align with other existing points or objects, snap to key intermediate positions along members, attach to existing objects, or align with existing members or global axes. You can even lock onto a node or member by briefly hovering over it and then begin drawing at some offset away from it. When aligned with an axis, member or point, you can also just type in the desired distance away your point should be.



A new combination load cases grid showing primary and combination load cases across the top and combination load cases down the side. You simply type multiplying factors into any cells to quickly build up your combination load cases in a very visual way. Rows for new combination load cases can be added as desired.



Customizable toolbars.



A view selector showing the current viewpoint. It can also be dragged around or clicked to change the orientation of the model.



Unlimited undo/redo steps.



More detailed infotips when hovering over a node, member or plate.



New libraries in XML format that now hold non-standard and built-up sections, directly editable via the shape builder and/or library editor. Categories have also been added for Common, Special, Legacy and Obsolete classifications.



A new moving loads generator incorporating animated views of the vehicles travelling over your model. Horizontal loads and moments can now be added to 15

SPACE GASS 12 User Manual vehicles. Travel paths can now be drawn graphically, as can a loading area outside of which wheels are treated as inactive even if they are still within the ends of their travel path. A new vehicle editor has also been added, and vehicles are now incorporated into the standard libraries.

16



A load case manager now lets you copy, renumber or delete multiple load cases rather than one at a time.



buttons throughout SPACE GASS that allow to select from load cases, sections or materials that already exist in the job, plus a load case titles viewer that can be left open all the time if you need to see which load cases are which.



A new area loads generator with options for two-way and one-way loads. Load directions include X, Y, Z, "Normal to area" and "Vector". Loading areas can be actual or projected, and more than four members per polygon can now be handled.



A new renumbering tool that offers renumbering in three directions simultaneously.



A taper/haunch tool that now subdivides automatically if required.



A new find tool with additional modes for finding duplicated nodes, invalid plates, members duplicated in steel member groups, members with free ends and plates with free vertices.



New move, rotate, copy, mirror, stretch and scale tools that allow you to select nodes, members or plates. They also provide a graphical preview of the final result before the changes are made.



Textures such as "brickwork", "steel" and "concrete" that can be added to members or plates and shown graphically.



Gridlines that can be defined and shown graphically in two directions at any spacings and then used as snap and reference points when drawing objects or locating points.



A tool for converting static loads such as dead loads and live loads into masses for use in a dynamic analysis.



A new curve editor for spectral curves that has extra capabilities for importing, exporting, labelling and an equation data generation tool.



A view manager that lets you save the current view into a list of saved views and then recall them as desired.



Moveable property panels that list all of the sections and materials used in your model. You can even click on a section or material in the panel to select all the members or plates in your model that use that item.



A member alignment tool that lets you align or stack members via their center, top, bottom, left or right sides.



An option for showing member origins graphically. This quickly lets you see which way each member is running.

Introduction 

Generation of bends of any radius at member intersections. A very useful tool for pipework analysis.



A tool for reversing the direction of members. Options for adjusting member fixities, offsets and loads are included.



Various tools for extending members along their length, moving intermediate nodes, removing intermediate nodes and removing crossed member nodes.



A new steel member design module for the Hong Kong code HK CP2011 has been released.

Version 10.8 

Steel member design modules for the AISC 360-10 LRFD and ASD standards have been released.



SPACE GASS now uses the Titan license manager softlock system instead of hardware locks, although hardware locks can still be supplied if requested. TitanLM suppports stand-alone or network installations, and lets users borrow licenses from the network for use off-site.

Versions 10.6 to 10.7 

A new plate element has been added in v10.7. Plate elements can be quadrilateral or triangular with bending, shear and membrane stiffness.



SPACE GASS can now import and export data in CIMSteel/2 (CIS/2) and IFC Step file formats. This allows it to communicate directly with many other programs such as Tekla Structures/XSteel, ProSteel, Microstation, Frameworks Plus, AutoCAD, Revit Structure, StruCAD, etc.



A new built-in graphics rendering module has been added in v10.7 that allows you to generate realistic rendered models of your job that show the complete geometry of all members and plates. This replaces the old internal 3D viewer and the external VRML viewer. It is expected that this module will gradually be given full input, editing and viewing functionality until it completely replaces the existing graphics system in SPACE GASS.



Nodes can now be moved, rotated or deleted directly in v10.7.



Rotated and/or flipped members can now be located using the find command or filtered in v10.7.



In v10.7 graphical envelopes can now be limited to minimums and maximums, just minimums, just maximums or just absolute maximums.



The minimum and maximum intermediate values are now shown on displacement, bending moment, shear force, axial force, torsion and stress diagrams in v10.6.



A new connectivity tool has been added that allows you to check what is connected to any given node, member or plate.

Versions 10.1 to 10.5

17


18



An interface to Autodesk’s Revit Structure program has been added in v10.51b.



The dynamic response analysis module now supports AS1170.4-2007 and NZS1170.5-2004



Dynamic zoom, pan, viewpoint and diagram scale changing have been added in v10.50. Your current operation stays active and none of your node, member or plate selections are lost while you are using these tools. Refer to shortcuts for more information.



SPACE GASS can be run minimized, normal or maximized (the default mode) depending on the -min, -nml or -max command line options. It can also be controlled by the SHOW line in a script file. These changes were made in v10.50a.



The concrete material properties in the standard metric library have been updated in v10.50a. The new values are based on AS3600-2001 clauses 6.1.5, 6.1.6 and Commentary Table C6.1.2.



Importing/exporting MS-Excel, MS-Word or MS-Access data can now be done in script mode in v10.50.



"D" restraints are no longer supported in v10.50. Restraints are now just "F", "R" or "S".



The structure wizard no longer generates general restraints and is less restraining in general in v10.50.



Importing of SDNF version 3 files is now supported in v10.50.



A new steel member design module for the Hong Kong code HK CP2005 has been added in v10.41.



A new steel member design module for the British code BS5950:2000 has been added in v10.41.



When exporting to DXF, the frame data can now be put into section-specific layers rather than having the entire frame in one layer.



A new steel member design module for the LiteSteel beam range of sections from Smorgon Steel has been added in v10.40. These are designed to AS4600.



The tool that updates analysis section property data based on the results of a steel member design has been enhanced considerably so that it allows the update-analysisdesign procedure to be iterated automatically.



A new dynamic frequency analysis solver has been added in v10.30. It allows you to create combinations of mass load cases and to combine lumped mass load cases with self weight load cases. The new solver uses the wavefront optimizer and, as a result, the computer’s memory requirement is vastly reduced.



An option for SPACE GASS to check for program updates via the SPACE GASS website has been added.

Introduction 

The moving load generator is now able to generate combination load cases that combine the moving loads with other static loads.



Moving load travel path coordinates, when used in conjunction with travel path node numbers, are now treated as offsets from the path defined by the node numbers.



The number of moving load wheels per vehicle has been increased to 200.



Custom libraries are now stored in a separate file to the standard libraries. They can also be stored in a different folder to the standard libraries.



Your company logo can now be scaled to an exact height that you specify and can optionally be included on every page or just the first page. JPG images formats are also now supported.



Saving of loads after graphical editing, importing of text files and report generation have all been sped up dramatically.



Zooming via the mousewheel is now centered on the mouse position.



Selection of the local XY and/or XZ planes for the display of moments, shears and stresses can now be made direct from the side toolbar rather than via a filter.



New members being drawn graphically can now be optionally given the default attributes or those of the previously accessed member.



An option for allowing duplicate members to be drawn has been added. Finding and filtering duplicate members has also been added to the cleanup, find and filter functions.



Deleting members with zero length has been added to the cleanup function.



Filters defined in terms of analysis members now also affect steel design reports.



Options for suppressing automatic re-scaling of load and analysis results diagrams have been added.



An option for selecting steel members and connections graphically and then viewing or editing them in a datasheet has been added.



The default bolt, plate, weld, rebar, spectral and vehicle library names can now be specified in the configuration.



The lowest buckling load factor is now displayed at the end of a buckling analysis.



The end offset distance for members exported to a DXF drawing file can now be specified.



The data generated by the structure wizard is now adjusted according to the vertical axis setting.



The default gravity direction in the self-weight datasheet is now adjusted according to the vertical axis setting.



Auto-created steel members are now terminated at pin-ended members. 19


Version 10.00

20



A facility for generating moving loads has been added.



Other jobs can be opened and merged with the current job.



Steel member design input data can now be generated automatically for the entire model.



A facility for connecting members that cross over each other has been added.



Print previews can be produced.



Your company logo can be included in text and graphical reports.



The analysis and design output has been combined into a single report.



Text reports can be exported to PDF, HTML and TXT files.



Graphical output can be exported to PDF, HTML and BMP files.



All symbols are now shown correctly in reports.



A new page setup form gives you full control over the output device, margins, page layout and formatting.



You can specify and configure separate graphics and text printers.



USB network locks are supported.



If the program is terminated abnormally, any network licences that were active are recovered immediately and automatically.



Mouse wheel zooming, panning and viewpoint changing is supported.



Keyboard zooming, panning and viewpoint changing is supported.



Keyboard scrolling through filters, views and load cases is supported.



Temporary job files are now stored on the local workstation for extra speed and much reduced network traffic.



Filters, views, etc. in the current job can be retained when data is imported from a text file.



In order to detect the cause of frame buckling, the nodes at which the maximum translations and rotations occur are listed in buckling reports.



Tension/Compression-only effects can be made to revert to "no reversal" mode after a specified number of iterations.



Unrestrained degrees of freedom are now automatically stabilised during the analysis. This prevents many instabilities due to incorrect modelling.

Introduction 

Cable members no longer require uniformly distributed loads to be applied to them.



Nodes connected only to cable members no longer have to be restrained rotationally.



Error messages can be printed or copied to the clipboard.



Export files include all input data and are no longer affected by filters or report selections.



You can print or obtain print previews direct from the datasheets.



SPACE GASS can now import and export data directly with MS-Excel, MS-Access and MS-Word.



Options for springs and compression-only members have been added to the structure wizard beam and grillage structures.



Compression effective lengths in the steel member design input data can be fully controlled separately for each axis.



The automatic reduction of the minor axis compression effective length due to flange restraints is now optional.



Steel members can be nominated as "braced " for either or both axes in order to limit the compression effective lengths to their actual lengths.



Double angles are shown as such in the graphical section property legend.



Steel members that have been offset can now be designed.



Everything attached to and associated with a member is deleted when the member is deleted. This includes attributes, offsets, loads and design input data.



The steel design input data member lists are automatically adjusted when members are deleted, subdivided or otherwise edited graphically.



Steel members and connections are now sorted numerically if input or edited graphically.



Abandoned unnamed jobs can now be recovered automatically.



Undo for all design input data is supported.



Undo for node, member and plate renumbering is supported.



Cleanup for all design input data is supported.



The area loader supports subdivided members.



Single angle sections can be designed as concentrically connected.



The properties of a node can be copied to a graphical selection of other nodes.



The properties of a member can be copied to a graphical selection of other members.

21


22



The design input data for a steel member can be copied to a graphical selection of other steel members.



Loads can be copied from a node to a graphical selection of other nodes.



Loads can be copied from a member to a graphical selection of other members.



You can press the space bar to repeat the last graphics command.



An external macro such as another program, batch file or MS-Excel/Access macro can be run from within SPACE GASS.



SPACE GASS can be controlled externally from another program or batch file using a script file.



A backup copy of the job is made just before each save.



Full 3D geometry displays can be saved in VRML files for later viewing.



Buttons have been added to the library editor for adding, deleting and editing.



A large number of minor improvements, bug fixes and adjustments have been incorporated.

Installation and Configuration Installation and configuration Installation and configuration of SPACE GASS is a simple two-stage process that is explained in the following sections.

23


Installing SPACE GASS The installation procedure involves downloading and installing SPACE GASS on your computer and then registering it for the modules you are licensed to use. The registration procedure also involves linking SPACE GASS to your specific Titan softlock or hardware lock. For detailed instructions, refer to www.spacegass.com/install.

24

Installation and Configuration

Configuring SPACE GASS You can run SPACE GASS by double-clicking the SPACE GASS shortcut that was created when it was installed. When you first start SPACE GASS, or if you make any changes to your system, you will be prompted for some configuration information. After the initial configuration, you can change any of the configuration settings by selecting them from the Config menu. The eight configuration forms are detailed in this chapter. All configurable data is stored in a number of files called SG.INI, SGSettings.GS and various XML files. They are all stored in the LocalAppData folder (eg. c:\Users\Fred\AppData\Local\SPACE GASS\12). Note that you can quickly reset SPACE GASS back to its default configuration settings by running the SPACE GASS Utility Tool (via the Start button => All Programs => SPACE GASS 12 => Tools => SPACE GASS Utility) and clicking the "Reset Client Configuration" button or the "Reset All" button. For more information, refer to The SPACE GASS utility tool.

25


Folders and files Select "Folders and files" from the Config menu. This form allows you to set the folder locations for the SPACE GASS program itself and for the various types of data files.

Main program folder Contains the SPACE GASS program itself. Main data folder Contains the main job data files. Standard libraries folder Contains the standard section, material, bolt, plate, weld, spectral curve, reinforcing bar and vehicle libraries supplied with SPACE GASS. This normally matches the main program folder, however it can be different if you wish to have the standard libraries in a separate folder. Note that all standard libraries are contained in a file called sglibstandard.mdb which cannot be modified.

26

Installation and Configuration Custom libraries folder Contains the custom section, material, bolt, plate, weld, spectral curve, reinforcing bar and vehicle libraries that you create. These can be in the same folder as the standard libraries or in another location. Note that all custom libraries are contained in a file called sglibcustom.mdb which can be modified via the library editor or the shape builder. If you wish to have the SPACE GASS program folder write protected then you must change the custom library folder to a different location. Text data folder Contains import/export text data files and print text files. Backup data folder Contains import/export backup job data files. Archive data folder Contains import/export archive data files. CAD data folder Contains import/export CAD data files. Temporary data folder Contains temporary files that are created and deleted by SPACE GASS as it operates. Documents folder Contains MS-Access, MS-Excel and MS-Word document files. Text editor program The name of the SPACE GASS text editor. This can be the standard Windows NOTEPAD or any other text editor that runs in Windows. Calculator program The name of the SPACE GASS calculator. This can be the standard Windows calculator or any other calculator that runs in Windows. Default library names The names of the default libraries. Note that any folders that do not exist are automatically created as you go. Copy the Job to the Backup Data Folder Before Saving If this box is selected, whenever a job is saved, a copy of the previously saved version of the job is copied to the backup data folder and renamed with an extension of BAK.

27


Text formatting Select "Text formatting" from the Config menu. This form allows you to set the report and graphics text formats and fonts.

Report text format The report text format which is initially selected when you create a new job. Note that this setting does not change the current job. The report text format for the current job can only be changed from the report form (selected from the Output menu). Graphics text format The graphics text format which is initially selected when you create a new job. Note that this setting does not change the current job. The graphics text format for the current job can only be changed from the Labelling and Annotation form (selected from the View menu). Report font The font for text reports. This must not be a proportional font otherwise the columns of numbers in reports will not line up properly. The two-column output toggle switches between one-column and two-column output in the report. Screen graphics font The font for screen graphics text. This can be any proportional or fixed font. After setting the screen graphics font size, if the text on the SPACE GASS graphics screen looks too big or too small, it may be because the screen graphics correction factors have not been set correctly. Refer to "Graphics scale calibration" in "Graphics scale calibration" later in this chapter. Printer graphics font The font for printer graphics text. This can be any proportional or fixed font.

28


General configuration Select "General configuration" from the Config menu. This form allows you to set the general purpose configuration items in SPACE GASS.

Sound on alert This allows you to suppress or enable the sound that the program makes when it wants to alert you to something. Sound on error This allows you to suppress or enable the sound that the program makes when an error occurs. Diagram shading Loading, bending moment, shear force, stress and axial force diagrams are shaded if this item is ticked.

29

SPACE GASS 12 User Manual Shading is normally turned off as it makes multiple superimposed diagrams hard to read. Check disk space If this item is ticked, SPACE GASS performs a disk space check to ensure that there is enough free space for a static or dynamic analysis to proceed to completion. If the disk space check has been disabled and there is not enough space for the analysis data, the program may abort with an error message. Although this is not a desirable occurrence, it will not result in loss of data. Vertical axis The graphics vertical axis which is initially selected when you create a new job. Note that this setting does not change the current job. The graphics vertical axis for the current job can only be changed from the Viewpoint form (selected from the View menu). Changing this setting only affects the graphics display. It doesn’t affect the local axis definitions, the steel design top flange definitions, or the analysis and design modules in any way. Aperture size The size of the aperture circle which appears when nodes and/or members can be selected graphically. Crosshair size The size of the crosshair which appears when snap or ortho modes are on. Curve resolution All curved lines drawn with SPACE GASS are actually a series of short straight lines. In most cases it is very difficult to differentiate between a true curve and a series of ten straight line segments placed around the curve. SPACE GASS allows you to specify how many straight line segments per member are used to approximate curved lines in displacement, bending moment, shear force or axial force diagrams. Use previous attributes when drawing new members If this item is ticked, any new members that you draw will have the same attributes as the member that was previously drawn or edited graphically. If unticked, newly drawn members will have the default attributes. Allow duplicates when drawing new members Tick this item if you wish to be able to draw multiple members between the same two nodes. For example, you may wish to have two members that share the same end nodes but which are offset away from each other by some distance. This may be applicable for double angle members that have a gap between them. If you have drawn duplicate members and wish to locate them, you can do so by using the Find tool and selecting "Duplicated" in the member type field. You can also use a similar procedure to create a filter that isolates any duplicated members. Allow automatic prompting for load case titles If you want to be prompted for a load case title each time you input loads for a new load case then you should tick this option. Automatically open the renderer when SPACE GASS starts Now that the renderer has all of the tools that are available in the traditional SPACE GASS window it has become the new default user interface. This option lets the renderer open automatically at start-up rather than you having to do it manually. 30


Start with the traditional SPACE GASS window minimized If this option is ticked, the renderer will open automatically at start-up and the traditional SPACE GASS window will not appear. If you occasionally want to use the traditional SPACE GASS window you can simply restore it from the taskbar and then minimize it again when you are finished with it. Re-scale load diagrams after load editing If this item is ticked, load diagrams will be re-scaled automatically whenever any distributed member loads are changed. Re-scale result diagrams after analysis If this item is ticked, the analysis diagrams will be re-scaled automatically whenever an analysis is completed. Draw positive bending moments on tension/compression side The convention for drawing bending moment diagrams varies from country to country. SPACE GASS can be configured to draw bending moments on either the tension or compression side of a member. Shorten members in DXF files When exporting to a DXF file, you can allow the members to be drawn full length or you can have them shortened at each end by a proportion of the member depth. For example, a member with a depth of 500mm could be drawn 250mm shorter at each end by using a depth factor of 0.5. Dashed lines Dashed (broken) lines are used to differentiate between load cases and between diagram types. All lines are drawn continuous if dashed lines are not allowed. DXF layer names Layer names are only applicable if you have the CAD interface module. These are the layers into which the drawing will be placed when you transfer it into your CAD program. It is recommended that you make each layer name different so that it is easy to distinguish between centrelines, text, members, hidden lines, attributes, bolts, plates and cut-off lines. It is also recommended that you set the hidden line layer in your CAD software to dashed or dotted lines. Automatically check for program updates SPACE GASS can automatically check its website to see if a newer version is available. If so, a notification message is displayed and you have the option of downloading and installing the update.

31


Graphics scale calibration Select "Graphics scale calibration" from the Config menu. This form allows you to calibrate your monitor so that graphics is properly sized and proportioned.

Some monitors exaggerate the horizontal and/or vertical scales so that the SPACE GASS graphical output appears stretched or compressed in either or both directions. SPACE GASS allows you to apply correction factors which allow for these exaggerations and adjust the graphical output so that it is correctly sized and proportioned. You should simply measure the width and height of the two lines on the screen with a ruler, and SPACE GASS calculates the correction factors for you. ! IMPORTANT NOTE ! Ensure that you measure between the arrow heads rather than measuring the overall form or screen size, otherwise items on the SPACE GASS graphics screen will appear too small or too large.

32


Graphics colors Select "Graphics colors" from the Config menu. This form allows you to select colors for screen, printer and plotter graphics output.

Colors are selected by first clicking the item to be changed and then selecting a color from the palette at the bottom of the form. The list of color indexes next to "Section properties" represents section properties 1-25. If you have more than 25 section properties, the pattern is repeated for properties 26-50, 51-75, etc. The list of color indexes next to "Load cases" represents the first 25 load cases. If you have more than 25 load cases, the pattern is repeated for each additional group of 25 load cases.

33


General colors Select "General colors" from the Config menu. This form allows you to set the Windows color scheme. It controls items such as form colors, button colors, scroll bar colors, etc.

When you select this option SPACE GASS loads the standard Windows color selection form which can also be selected from the Windows Control Panel. The appearance of this screen is dependant upon the version of Windows you are running.

34


Problem size limits Select "Problem size limits" from the Config menu. This form allows you to set maximum job size limits.

SPACE GASS has been dimensioned dynamically. This allows it to expand into the available memory of your computer giving you virtually unlimited problem size capacity dependant only on the memory capacity of your computer. The size limits you set allow you to reserve space for a job, with space being allocated according to the size of each component of a job. You should set the limits high enough so that there is enough capacity for the largest of jobs that you are likely to encounter but small enough that you don't exceed the memory capacity of your computer. Keep in mind that the limits can be changed at any time, even when you are halfway through inputting a job and find that you have run out of capacity. Just select "Problem size limits" from the Config menu and change the limits to suit your job size. After changing the limits you can simply return to where you left off, with all previously entered data retained.

35


Renderer configuration Various renderer settings and preferences are available from the Settings menu in the renderer as shown below.

In the following form: The "Alignment proximity" controls how close the mouse cursor must be to an axis aligned with a "locked on" node or member or a global axis in order to align with it. The "Cursor pickbox size" controls how close the mouse cursor must be to a node, member or plate in order to select it, lock onto it or display its infotip. The "Lock delay" controls how long the mouse cursor must be near a node or member before you lock onto it.

In the following form: The "Use previous attributes..." option, if ticked, means that when you draw a new node, member or plate it will have the same properties (ie. section ID, material ID, etc) as the previous item you drew or selected.

36

Installation and Configuration The "Allow duplicates..." option lets you draw members or plates on top of existing members or plates (ie. so that they share the same nodes). The "Allow hidden nodes to be selectable" option allows you to select nodes that you can't see due to being behind other objects. The "Automatically prompt for new load case titles" option enables load case titles to be prompted for automatically each time a new load case is created. The "Anti-aliasing" option gives graphical text a smooth appearance by changing the color of pixels around the edges of the text. The "Order independent transparency (OIT)" option enables true (fully accurate) transparency for the display of transparent objects. If unticked (required by some older graphics cards) then the transparency is unsorted, resulting in some transparent objects appearing to be in front of objects that they should be behind. The "Support multiprocessor for RC beam design" option allows multiple zones to be designed/checked simultaneously during a reinforced concrete beam design. The "Use OpenGL for graphical forms" option controls the system used to display graphical objects in forms such as the shape builder, moving loads generator, steel connection design module, reinforced concrete design modules, portal frame builder, etc. If unticked then DirectX is used. Note that this setting doesn't affect the graphical system used in the main renderer window. The "Disable OpenGL shaders" option should be unticked for maximum graphical speed in the renderer. If ticked (required for some older graphics cards) then the renderer uses a slow software emulation mode to display graphical objects rather than utilizing the parallel processing power of the graphics card. This option should only be ticked when the renderer becomes unstable due to an old or incompatible graphics card being used. The "Default deflection color" option, if ticked, means that when only one load case is displayed, deflections are shown by member color rather than load case color. If unticked or if multiple load cases are displayed then deflections are colored by load case. The "Curve quality" controls how many segments are used to display curved objects such as cylinders and the like. The "Result quality" controls how many short straight lines are used to approximate a curve when drawing deflected shapes, bending moment diagrams, etc. The "Structure line width" is the thickness of lines used to draw the structure when in wireframe or outline modes. The "Diagram line width" is the thickness of lines used to draw diagrams such as bending moment diagrams, etc. The "Maximum undo/redo steps" is the number of undo/redo steps that are remembered in the renderer. More memory is consumed if this setting is increased. The "Highlight delay" controls how long the mouse cursor must be near a node, member or plate before it becomes highlighted. Note that this setting has no effect over whether the node, member or plate is attached to when drawing new objects. The "Infotip delay" controls how long the mouse cursor must be near a node, member or plate before its infotip appears. The "Maximum load case components" is used to prevent memory overflow problems with large models that contain many load cases by limiting how many load cases can be displayed simultaneously. A "component" is considered to be a single diagram (eg. a load, a bending moment diagram, a shear force diagram, etc) on a single node, member or plate. If you experience memory problems when you try to display loads or analysis results graphically for many load cases simultaneously then you may need to lower this limit. Conversely, if your system has substantial memory and you are being restricted to an insufficient number of load cases when displaying loads or analysis results graphically then you could experiment with raising this limit. The "Rotation drag distance" is the number of pixels that you can move the mouse while the left button is held down before it will start to rotate the model. It is used to avoid the problem of the model rotating unintentionally when you are trying to select items or start a selection window. If this problem occurs then try increasing the rotation drag distance slightly. 37

SPACE GASS 12 User Manual The "Rotation mode" controls how the model behaves when you rotate it with the mouse. Trackball mode lets the model rotate about all three axes, whereas Turntable mode prevents rotation about an axis normal to your computer screen. Trackball mode is a bit harder to control than Turntable. The "Rotate at" setting controls the centre of rotation when you rotate the model by dragging with the left mouse button held down.

The following form lets you can change the theme of the renderer via the "Skin" setting. This affects the colors and styles of all the forms, buttons and input fields. You can also separately change the colors of most the items in your model to suit your requirements.

38


In the following form you can control the color and threshold of each pass or fail level when displaying steel member design results.

39


The size of the text displayed on the screen and in graphical prints can be controlled in the following form.

The "Other" menu option gives you access to some of the configuration settings normally found only in the traditional SPACE GASS window as follows:

40

Installation and Configuration For further information on each of these options, refer to "Folders and files", "Text formatting", "General configuration" and "Problem size limits". In particular, if you wish to change the vertical axis you should choose "Settings => Other => General Configuration".

41


Customizing toolbars All of the toolbars in the renderer can be hidden/shown, moved or undocked. Buttons can also be added or deleted.

In order to move or undock a toolbar, simply drag its handle on the left hand end of the toolbar to the desired location.

Undocked toolbars such as the one shown below can be placed anywhere in the renderer window or docked to the top, bottom, left or right sides of the renderer.

To hide a toolbar, simply right-click anywhere on it and then untick it from the list of toolbars that appears. To restore a toolbar, select Toolbars from the Window menu, click the Toolbars tab and then tick the desired toolbar.

42


Adding or deleting buttons To add or delete buttons, right-click anywhere on a toolbar, select Customize from the menu that appears and then click the Commands tab.

You can then select a toolbar from the list and add or delete buttons as required.

43


The Options tab also has additional settings that you might find useful as shown below.

For information on how to customize the renderer's property panels, refer to Customizing property panels.

44


Customizing property panels Property panels can be pinned open by clicking the button at the top of the panel so that it changes to . This means that it will stay open, even if not being used. If you click it again, it changes to , indicating that the panel is not pinned and will close when not required. If you want to close a panel manually then just click

.

You can undock a panel and place it anywhere on the screen or dock it to the left or right side of the renderer by first pinning it using and then dragging the title bar of the panel to the desired location. Note that when undocked, it will stay open when not being used.

45


For information on how to customize the renderer's toolbars, refer to Customizing toolbars.

46


The SPACE GASS utility tool The utility tool lets you reset the SPACE GASS registration and/or configuration settings, or attach your own logo to SPACE GASS so that it appears in the printed reports.

Reset Registration If you have a Titan softlock, this option resets SPACE GASS back to its freshly installed state. It is used primarily to start afresh in cases where SPACE GASS is having difficulty obtaining a Titan license. Note that this option resets the connection from SPACE GASS to the Titan server but does not affect the Titan server itself or its registration. If you have a hardware lock, this option de-registers SPACE GASS. The next time you run SPACE GASS it will initiate the re-registration process. It is used primarily to re-register SPACE GASS in cases such as when new modules have been purchased or when the hardware lock has been changed. For more information, refer to http://www.spacegass.com/install. Reset Client Configuration This option resets the SPACE GASS client configuration back to its default settings. The next time you run SPACE GASS it will initiate the re-configuration process. For more information, refer to Configuring SPACE GASS.

47


Reset All Choose this option to reset both the registration and client configuration. Set Report Logo You can use this option to set your own logo to appear at the top of your printed reports. You must first create a JPG image file that contains your logo and any text that goes with it. For best results, make the image file large enough so that it contains enough pixels for a printer resolution of at least 300 dpi. For example, if your printer operates at 600 dpi resolution and you want the printed logo height to be 20mm, your image file will need to be at least 472 pixels in height (ie. 600/25.4x20). Regardless of the size of your image file, it will be scaled to print at the exact height you specify in the page setup form. After creating your JPG image file, click the "Set Report Logo" button to display the following form.

You should then click the "Set Logo" button, browse to your image file and select it. Note that even after completing the above procedure, you must ensure that SPACE GASS is configured to use the logo. You can do this by choosing "Page Setup" from the SPACE GASS File menu, setting the logo height and specifying whether it is to be on the first page only or on all pages. For more information, refer to Page setup.

48

Getting Started Getting started This chapter explains how to start SPACE GASS and takes you on a guided tour of the main SPACE GASS window and all of its menus. It also explains how you should interact with SPACE GASS and respond to its requests for data.

49


Starting SPACE GASS Before proceeding with this section you should have copied and installed SPACE GASS (see also Installing SPACE GASS). In order to start SPACE GASS, you can either: 1. 2.

Double-click the "SPACE GASS" shortcut on your desktop. Double-click on a SPACE GASS job file (they end with .SG).

If you are running SPACE GASS for the first time, you will be taken through part of the SPACE GASS configuration program (see also Configuring SPACE GASS). You can control how SPACE GASS starts by the use of command line options. For example, you can bypass the splash screen, you can prevent the previous job from loading automatically, you can control the location of the SPACE GASS configuration file, etc. They are fully explained in Command line options.

50

Getting Started

Command line options You can control how SPACE GASS starts by adding one or more options to the command line in the shortcut you use to start SPACE GASS. To add a command line option, select "Properties" of your SPACE GASS shortcut and append the contents of the "Target" field with one or more of the following options. -n

Bypasses the automatic loading of the previously used job.

-p

Bypasses the splash screen.

-w

Bypasses the Internet check for new versions of SPACE GASS.

-c [bbggrr]

Allows you to set the datasheet alternate line color, where [bbggrr] is the 6 character hexadecimal representation of the desired color with bb=blue component, gg=green component and rr=red component. For example, 50% blue, 50% green and 20% red could be specified with a command line option of c7f7f33.

-s [file]

Allows you to specify a script file that contains a list of menu commands and other items that SPACE GASS will automatically execute one-by-one rather than you operating it in the normal way. For example, a command line option of -s "c:\scripts\myscript.txt" would load the myscript.txt script file from the c:\scripts folder. Note that the ""s can be omitted if this option is at the end of the target field. See "Running a script" for more information and full details of the script file format.

-min

Runs SPACE GASS minimized so that it is not visible except for an icon on the taskbar. This can be useful when SPACE GASS is controlled by a script file (see the -s command line option above), although it may be more convenient to use the "SHOW MIN" command in the script file to achieve the same effect. See "Running a script" for more information and full details of the script file format.

-nml

Runs SPACE GASS in a normal window that is usually smaller than the overall screen size.

-max

Runs SPACE GASS maximized so that it fills the entire screen area. This is the default setting and is the same as if none of the -min, -nml or -max command line options are specified.

Note that the -min, -nml and -max command line options can be overridden by the SHOW line in a script file. See "Running a script" for more information and full details of the script file format.

51

SPACE GASS 12 User Manual For example, to bypass the splash screen and the automatic loading of the previously used job, you could have a shortcut target field of: "C:\Program Files\SPACE GASS\Exe\sgwin.exe" -p -n If you start SPACE GASS by double-clicking on a job, then the shortcut is bypassed and any command line options in it are not used. You can, however, apply the command line options when a job is double-clicked by starting Windows Explorer, selecting Tools –> Folder Options from the menu, clicking the File Types tab, scrolling down to and clicking the SG file extension, clicking the Advanced button, clicking the Edit button and then adding the command line option to the end of the "Application used to perform action" field. Note that you can use the -i command line option to set up multiple shortcuts, each with its own SG.INI file for cases where you want to be able to run SPACE GASS with different configurations. For example, you may have a laptop that is normally connected to the office network during which SPACE GASS needs to access jobs and libraries that are stored on the network. However, there may also be times when the laptop is being used away from the network on-site or at home. It would be convenient if these two scenarios could each have its own folder settings and other configuration items. You can set this up by simply making a copy of your SPACE GASS shortcut so that you have a shortcut for when you are connected to the office network and another for when you are running SPACE GASS away from the office, each with its own SG.INI file and configuration settings. Edit the properties of each shortcut and add -i "path" to the end of the target field, where "path" is the folder containing the SG.INI file. For example, -i "c:\SG\Config\Office" would store the SG.INI file for that shortcut in the "c:\SG\Config\Office" folder, and -i "c:\SG\Config\Home" would store the SG.INI file for that shortcut in the "c:\SG\Config\Home" folder. The next time you run SPACE GASS from either shortcut, it would run through the configuration process and let you set them up with their own unique configuration settings.

52

Getting Started

The main SPACE GASS window When you start SPACE GASS, the following main window appears with the structural model for the current job displayed in it. You can also click the window.

button to open the renderer

The title bar This is the colored band across the top of the window, it contains the SPACE GASS version, the name of the current job and the scale of the viewport if it is being displayed in full-screen mode. The menu bar The second band across the top of the window contains the twelve main menu items. By selecting one of the main menu items you can gain access to all of the options contained within that menu. The menu bar allows you to access all of the program’s features (see also The menu system). The toolbars The buttons across the top and to the left of the display area form the toolbars. The toolbar buttons replicate the most commonly used menu items and give you instant access to them (see also The toolbars). The graphics settings buttons across the bottom of the screen display the current settings for the drawing tool and allow the settings to be toggled.

53

SPACE GASS 12 User Manual The graphics display area The area in the centre of the main window displays the structural model for the current job. The global axes are also shown in the top-right corner. You can display up to four viewports in this area. The text display area The area below the graphics settings buttons forms the text display area. The first line displays the project heading, job heading and the local axis settings. The second line is a multi-purpose line which usually contains the status line, but which also periodically displays other prompts and messages, some of which are purely informative and some of which require you to respond.

54

Getting Started

The status line

The status line appears in the second line of the text display area of the main SPACE GASS window. It is also displayed at the bottom of the renderer. The status line indicates which data is present for the various parts of the current job. The presence (or absence) of data is indicated by sequences of characters shown as follows. In all cases, unless otherwise indicated, "Y" represents "data exists", while "N" represents "no data exists". If, for example, you have performed a static analysis, a dynamic frequency analysis and an elastic buckling analysis (but no dynamic spectral response analysis), the "Analysis" part of the status line would appear as "Analysis:YYNY".

You can use the status line as a check to ensure you have entered sufficient data before performing another operation. For instance, you cannot perform a static analysis until you have applied some type of load to the structure (in addition to which, sufficient data must be present on the structure itself). Check for the appropriate code in the status line window before proceeding with the operation. Headings 1. Project name, Job name, Designer’s initials and Notes (Y/N) Structure 1. Nodes 2. Members 3. Plates 4. Restraints 5. Sections 6. Materials 7. Master-slave constraints 8. Member offsets (Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N) Loads 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Node loads Prescribed node displacements Member concentrated loads Member distributed forces Member distributed torsions Thermal loads Member prestress loads Plate pressure loads Self weight Combination load cases Load case titles Lumped masses Spectral load data

55

SPACE GASS 12 User Manual (Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N)(Y/N) Analysis 1. Static analysis, where "N"=not analysed, "Y"=analysed, "U"=desired convergence not obtained, "I"=ill-conditioned 2. Dynamic frequency analysis, where "N"=not analysed, "Y"=analysed 3. Dynamic response spectrum analysis, where "N"=not analysed, "Y"=analysed 4. Buckling analysis, where "N"=not analysed, "Y"=analysed (Y/N/U/I)(Y/N)(Y/N)(Y/N) Steel 1. Steel member design data 2. Steel Member design/check results, where "N"=not designed or checked, "D"=designed, "C"=checked 3. Connection design data 4. Connection design results, where "N"=not designed, "D"=designed (Y/N)(D/C/N)(Y/N)(D/N) Concrete 1. Concrete column design data 2. Concrete beam design data (Y/N)(Y/N)

56

Getting Started

Using the mouse This section gives basic information about using the mouse. If your mouse has more than one button, use the left button unless specifically told otherwise. The right mouse button is generally used by SPACE GASS to replicate the keyboard ESC key. The ESC key generally enables you to abort from the current operation or form. Note, however that the right mouse button is not always active, such as when a form is open. The following definitions explain the basic terms that are associated with using the mouse. Pointer The descriptive cursor that appears on the screen and tracks the mouse movement. Point Position the pointer on an item. Click (or Pick) Point to an item, and then quickly press and release the left mouse button. Right Click Point to an item, and then quickly press and release the right mouse button. Double-click Point to an item, and then quickly press and release the left mouse button twice. Drag Point to an item, press and hold the left mouse button as you move the mouse to a new location, then release it. Mousewheel Rotate the mousewheel to dynamically zoom, pan or change the viewpoint. For more information, refer to Shortcuts.

57


Dialogue boxes When you choose a command, a form often appears so that you can select options or type in data. If an option is dimmed, it is not currently available.

Using the keyboard with a form Although it’s usually easiest to use a mouse while you work in a form, you can also select options or fill in information with the keyboard. Some of the standard keyboard operations that you can use in forms are as follows. TAB SHIFT+TAB ENTER ESC ALT

Move to the next field in the form. Move to the previous field in the form. Equivalent to selecting the Ok button. Equivalent to selecting the Cancel button. If an option, box or button has an underlined letter in its name, you can choose that item by holding down ALT while typing the underlined letter.

Moving a form You can move a form dragging its title bar to the new location. The title bar is the colored band along the top of the form. Closing a form You can close a form by pressing the Ok or Cancel buttons. Alternatively, if the form has a control-menu box at the left side of the title bar, you can double-click on it to replicate the

58

Getting Started cancel button. If you single click the control-menu box, a control menu appears which also allows you to close or move the form.

59


Data entry Forms can contain a wide variety of data entry fields, boxes, options and buttons. Some of the commonly used ones in SPACE GASS are: Command buttons

You choose a command button to initiate an action, such as carrying out or cancelling a command. The Ok, Cancel and Help buttons are common command buttons. In SPACE GASS, they are usually located in the top-right corner of the form. To choose a command button, you can either click on it or press TAB until the button you want is selected, and then press ENTER. Scroll bars Some windows and forms have scroll bars which you can use to view information that does not fit inside the window. If you can view all of the contents of a window or form without having to scroll, the scroll bars may be absent or dimmed to indicate that they cannot be used. Scroll bars have a scroll arrow at each end with a moveable scroll box in between. To scroll through information displayed in a window or form, drag the scroll box to the desired position. To scroll one line at a time, click the scroll arrows, or to scroll continuously, hold a scroll arrow down. To scroll one page at a time, click the scroll bar on either side of the scroll box. Text boxes You can type appropriate information directly into text boxes. Text boxes are generally sideways scrollable so that they can hold more data than can be displayed in the box. Sometimes numeric text boxes have arrow buttons attached to them. These are called "spin buttons" and you can change the number in the text box, without actually having to type anything, by clicking the arrows or holding them down. When entering data into a text box, you will find that quite often a default value is already displayed there. If a default value is highlighted then as soon as you start typing it will be erased. To edit a default value without causing it to be erased, you can simply click somewhere in the text box or press one of the keyboard ARROW keys before you begin typing. The point where you clicked becomes the insertion point for the new text. If you want to highlight text in a text box, you can simply drag the pointer across the text, or double-click on a word to select one word at a time. Any text that you type will then replace the highlighted text. You can also delete highlighted text by pressing "DEL" or "BACKSPACE". Generally, when you select a text box by clicking on it, its default value does not become highlighted, however if you use the TAB key to get to the text box, its default value does become highlighted.

60

Getting Started List boxes

Display a list of items in a scrollable window from which you can make a selection. In special circumstances, you can sometimes select more than one item from a list box. Combo boxes Appear initially as a rectangular box containing the current selection. When you select the down arrow in the square box at the right of the selection, a list of available choices appears. If there are more items than can fit in the box, scroll bars are provided. Radio buttons

Represent a group of mutually exclusive options. You can select only one option at a time. If you already have one option selected, your current selection replaces it. The selected radio button contains a black dot. Check boxes

Represent non-exclusive options. You can select as many check box options as needed. When a check box is selected, it contains an X. Lists Sometimes SPACE GASS will ask you to provide a list of items such as nodes, members or load cases. Lists can be typed in as integers separated by commas or dashes. If, for example, your list was to contain the items 1,2,6,7,8,9,13,14,15 and 20, you could type it in as 1,2,6,7,8,9,13,14,15,20 or as 1,2,6-9,13-15,20. Dashes simply allow you to list a range of numbers. A special type of list is used to input flange restraint positions in the steel member design modules. This list accepts @’s (AT symbol) instead of dashes and can be used to quickly input a number of equally spaced flange restraints. For example, a list containing the following numbers 1.2,2.4,3.6,4.8,6.0,6.6,7.2,7.8,8.4 could be replaced with [email protected],[email protected]. When using a file selection form in which you have to scroll to get to the file you want, you can simply type in the first couple of characters of the file name to automatically scroll it into view.

61


Managing job files SPACE GASS jobs end with ".SG". Whenever you run SPACE GASS, it loads and displays the job that you previously had open. The procedures for starting new jobs, opening previously saved jobs, merging jobs, saving jobs, deleting jobs and cleaning up jobs are explained in the following sections.

SPACE GASS jobs are actually ZIP files renamed from {Job}.ZIP to {Job}.SG. You can manually open and view their contents with WinZip, however be careful not to make any changes or SPACE GASS may no longer be able to open them.

62

Getting Started

Starting a new job You can start a new job by clicking the menu.

toolbar button or selecting "New" from the File

If you have unsaved changes to the current job file then SPACE GASS will ask you if you wish to save these changes.

63


Opening a job You can open a previously saved job by clicking the from the File menu.

toolbar button or selecting "Open"

You will be prompted for the name of the file you wish to open. SPACE GASS, by default, looks in the most recently accessed folder when opening a job.

64

Getting Started

Merging jobs You can open another previously saved job and merge it with the current job by selecting "Merge" from the File menu. It is a good idea to save the current job first so that you can recover it if required.

For the job being merged with the current job, you can specify whether you want to include its structural data (required), load data and/or design data. The insertion point is the location at which the (0,0,0) origin of the merged job will be located. The default insertion point will guarantee that no overlapping with the current job occurs. In order to prevent clashing of numbered items, the merged job will be adjusted so that its numbering starts after the highest numbers in the current job. This might prevent some jobs from being merged if there is not enough room between the highest numbers in the current job and the maximum numbers specified in the problem size limits. If this occurs, you could renumber the current job and/or the merged job before attempting the merge, or you could increase the problem size limits if they are not already at their maximum settings.

65


Saving a job You can save the current job by clicking the File menu.

toolbar button or selecting "Save" from the

Saves all changes made to the job. If you have not already created a name for the job (ie. if it is previously unsaved) then you will be prompted for a file name and a location (performs the same function as selecting "save as" from the file menu). "Save As" is similar to "Save", except that the job is saved under a new name that you specify. For example, if you open Job1, make changes to it and then use Save As to save it as Job2, Job1 will be left unchanged while Job2 will be the changed version of Job1.

66

Getting Started

Deleting a job You can delete a previously saved job by selecting "Delete Job" from the File menu. Deletes the entire job. Use it with care because the job cannot be recovered after it has been deleted.

67


Cleaning up a job You can clean up the current job by clicking the Job" from the File menu or the floating menu.

toolbar button or selecting "Clean-up

Cleans up your model by deleting obsolete items or items that are no longer connected to anything. For example, it will remove loads that are applied to non-existent nodes, members or plates, or section properties that are not being used by any members. It is very useful for quickly removing the causes of many analysis errors. The clean-up tool can also merge nodes that are within a specified distance of one another, transferring members, plates, restraints, loads, etc. from the deleted nodes to the retained nodes. If this action results in a change to the way the structure responds to the applied loads then an error message will be displayed and the clean-up will not proceed. Any pairs of nodes close together that are linked with master-slave constraints will not be merged. Dummy nodes can be removed provided they are not used as direction nodes for members or plates.

68

Getting Started

Running a macro Macros are simply programs external to SPACE GASS that you can run from within SPACE GASS using this tool. They can be MS-Excel or MS-Access programs, DLLs, ActiveX programs, EXE programs or batch files. Macros are not for running and controlling SPACE GASS from another external program. For that you should refer to Running a Script. You can open the macro management form by clicking the "Run a Macro" from the File menu or the floating menu.

toolbar button or selecting

To run a macro, simply double-click the macro name in the form shown below.

To add a new macro or edit an existing macro, just click the "Add" or "Edit" buttons in the above form and then fill in the details in the following form.

Macro Title is the name of the macro that will appear in the "Run a Macro" form. Macro Type specifies the type of macro that is involved. Macro File gives the location of the external program that will be executed when you run the macro. This is not required for ActiveX macros. Class Name is the name of the class in an ActiveX macro. Macro Name is the name of the macro in an MS-Excel or MS-Access macro. Parameter is a list of extra parameters that are passed to the macro. Examples of each type of macro are supplied with SPACE GASS and are located in the main program folder.

69


Running a script Scripts allow you to run and control SPACE GASS from another program external to SPACE GASS. Scripts are not for running an external program from within SPACE GASS. For that you should refer to Running a Macro. A script is simply a text file that contains a list of commands that SPACE GASS will automatically execute one-by-one. The script file can be located anywhere, and its name and location must be specified in the command line when SPACE GASS is started. For example, a command line option of -s "c:\scripts\myscript.txt" would load the myscript.txt script file from the c:\scripts folder. Note that the double quotes (" ") can be omitted if this option is at the end of the target field. If you don’t want SPACE GASS to be visible when running in script mode then you can use a "SHOW MIN" line in the script file as described below. You can create a script file manually using a text editor or you can write a program that will create the script file and hence be able to control SPACE GASS automatically. The commands in the script file allow you to select any of the SPACE GASS menu items, however currently only the import, export, analysis and exit functions will bypass their input dialogs when in script mode. All of the other functions will display their normal dialogs and messages and then continue with the script when you have responded to them. Any error messages will be displayed and cause the script mode to be terminated. Any informative messages or warnings will be added to the log file and will not cause the script to pause. If you want to run SPACE GASS normally, ensure that the -s script file option does not exist in the target field of the SPACE GASS shortcut that you use to start SPACE GASS, otherwise SPACE GASS will go into script mode and will execute all the script commands rather than allowing you to control it normally. The structure of a script file is as follows:

70

1.

A header line containing "SPACE GASS Script File" must appear before any other command lines.

2.

An optional LOGFILE line can be included between the header line and the first command line. It lets you generate a log file that contains a list of all the menu commands executed from the script file, plus any messages, warnings or errors that might occur while SPACE GASS is running in script mode. It’s format is "LOGFILE Filespec", where Filespec is the path and name of the log file you want to create.

3.

An optional SHOW line can be included between the header line and the first command line. You can use it to specify whether SPACE GASS runs in a minimized, normal or maximized window when in script mode. It’s format is "SHOW MIN", "SHOW NML" or "SHOW MAX". "SHOW MIN" runs SPACE GASS minimized so that it is not visible except for an icon on the taskbar. This is probably the most useful setting for running SPACE GASS in script mode. "SHOW NML" runs SPACE GASS in a window that is usually smaller than the overall screen size. "SHOW MAX" runs SPACE GASS maximized so that it fills the entire screen area. This is the default setting and is the same as having no SHOW line in the script file.

Getting Started

Note that the SHOW line overrides any -min, -nml or -max command line options that might have been specified. See "Command line options" for more information. 4.

An optional PAUSE line can be included that allows you to pause the script. It can be useful if your script is not working properly and you want to see what stage it is up to at certain points in the script file.

5.

Command lines must appear exactly as "MENU MM SS [Extra]", where MM is a required 2 digit main-menu number, SS is a required 2 digit sub-menu number, and Extra is an optional list of parameters depending on the command. Extra can be up to 128 characters long and is used only as: (a) the file name when importing or exporting files. (b) the merge option when importing, where M signifies to merge rather than overwrite (eg. M c:\Data\MyData.XLS to merge file MyData.XLS with the current job). If the "M" is omitted when importing then the current job gets overwritten. (c) the type of static analysis, where LIN=Linear, SSF=Small displacement theory/Secant matrix/Full loading, SSR=Small displacement theory/Secant matrix/Residual loading, FSF=Finite displacement theory/Secant matrix/Full loading, FSR=Finite displacement theory/Secant matrix/Residual loading, FTR=Finite displacement theory/Tangent matrix/Residual loading, LSF=Large displacement theory/Secant matrix/Full loading, LSR=Large displacement theory/Secant matrix/Residual loading, LTR=Large displacement theory/Tangent matrix/Residual loading. Note that SSF, SSR, FSF, FSR, FTR, LSF, LSR and LTR are all non-linear analyses and are only applicable if MENU 04 02 is used. The above parameters can also be used to set the type of axial force distribution calculation in a buckling analysis when MENU 04 05 is used. (d) the list of load cases to be analysed, where CASES specifies the list (eg. CASES4,6,12-17,23,24 to analyse load cases 4, 6, 12-17, 23 and 24). Note that CASES0 signifies that all load cases should be analysed. (e) the solver type, which can be PARADISE, WAVEFRONT or WATCOM. (f) the optimization method when analysing, where NONE=None, AUTO=Auto, GEN=General, LX=Linear-X, LY=Linear-Y, LZ=Linear-Z, CX=Circular-X, CY=Circular-Y or CZ=Circular-Z. (g) the tension/compression-only effects activation in a static analysis, where TON=Activated, TOFF=Deactivated, TNR=No reversal after n iterations (eg. TNR5 for no reversal after 5 iterations). (h) the number of load steps in a non-linear static analysis, where STEPS specifies the number of steps (eg. STEPS1 for one load step). (i) the maximum number of iterations per load step in a non-linear static analysis, where ITNS specifies the maximum iterations (eg. ITNS10 for a maximum of 10 iterations per load step). (j) the convergence accuracy in a non-linear static analysis, where CNVG specifies the convergence (eg. CNVG99.99 for 99.99% convergence). (k) the lists of steel design groups, section properties and/or load cases when performing a steel member design or check. The lists can be specified as GROUPS, SECTIONS

71

SPACE GASS 12 User Manual and/or CASES (eg. GROUPS1-5,12,13,15-20 to export groups 1-5, 12, 13 and 15-20). Note that GROUPS0, SECTIONS0 and/or CASES0 signifies that all items should be included. Note that any analysis or design options not set by you via the Extra parameter are taken to be whatever was used in the previous analysis or design. For example, if you run an analysis of load cases 1,2,3 and 4, and then run another analysis in script mode with the CASES parameter omitted, it will also use just load cases 1,2,3 and 4. 6.

Comment lines are permitted anywhere in the file provided that they have a "#" before the first non-blank character.

7.

Blank lines are permitted anywhere in the file.

A sample script file follows: SPACE GASS Script File # Create a log file (optional) LOGFILE C:\Space Gass Data\Text\Logfile.txt # Import a text file (Textin.txt) MENU 01 15 C:\Space Gass Data\Text\Textin.txt # Perform a non-linear analysis with Linear-X optimization and tension/compression-only effects activated MENU 04 02 LX TON # Export a text file (Textout.txt) MENU 01 26 C:\Space Gass Data\Text\Textout.txt # Exit SPACE GASS MENU 01 41

Note that when you exit SPACE GASS via a script file, any changes to the current job will be abandoned. If you wish to save the changes then you should include a Save or Save-As command before the Exit command.

72

Getting Started

Job status You can display the current status of the job as shown below by selecting "Job Status" from the File menu.

73


Shortcuts Many of the menu items can also be accessed using a keyboard or mouse shortcut. Ctrl key shortcuts They are shown in the menus with Ctrl+K or Shift+Ctrl+K after them, where K represents the shortcut key. For example, to operate the Edit Libraries tool you must hold down the Ctrl key and then hit the L key (Ctrl+L). Alternatively, to access the Renumber facility you must hold down the Shift and Ctrl keys together and then hit the R key (Shift+Ctrl+R). Alt key shortcuts Every menu item also has an Alt key shortcut that is represented by an underlined character in the menu item names. If you hold down the Alt key, the underlining appears in the menus and you can then hit the underlined character on the keyboard to select the desired menu item. If there are more than one of the same underlined character in a menu, you can simply hit the underlined character multiple times until the desired menu item is selected. For example, to access the Units form you must hold down the Alt key and then hit the S key followed by the U key (Alt+SU). Alternatively, to access the Connect tool, you must hold down the Alt key and then hit the S key, followed by the C key three times (Alt+SCCC). Renderer shortcuts While using any of the renderer tools, various keyboard shortcuts are available that can speed things up. They are listed below. Shortcut Tab key F11 key G key S key X, Y or Z keys A key (hold down)

Action Toggles all of the property panels on or off Toggles full screen mode on or off Toggles the grid on or off Toggles the snap on or off Allows you to set the working plane Temporarily disables aligning with a "locked on" node or member C key (hold down) Temporarily disables attaching to a node or member Up/Down arrow keys Zooms in/out Rotate mousewheel Zooms in/out Drag with left mouse button Rotates Drag with right mouse Pans button Many of the other shortcuts listed below are also available in the renderer Other shortcuts The following list shows a number of special mouse and keyboard shortcuts that operate some of the most useful and commonly used tools. Action Zoom in Zoom out Zoom full Zoom previous

74

Keyboard shortcut Up arrow Down arrow Right arrow Left arrow

Mouse shortcut Mousewheel forwards Mousewheel backwards

Getting Started

Pan down Pan up Pan left Pan right Pan in renderer

Ctrl+Up arrow Ctrl+Down arrow Ctrl+Right arrow Ctrl+Left arrow

Rotate down Rotate up

Shift+Up arrow "V"+Mousewheel forwards Shift+Down "V"+Mousewheel backwards arrow Shift+Right arrow "H"+Mousewheel forwards Shift+Left arrow "H"+Mousewheel backwards Hold the left mouse button down and move the mouse

Rotate left Rotate right Rotate in renderer

Ctrl+Mousewheel forwards Ctrl+Mousewheel backwards Shift+Mousewheel forwards Shift+Mousewheel backwards Hold the right mouse button down and move the mouse

Enlarge load diagram Reduce load diagram

"L"+Up arrow "L"+Mousewheel forwards "L"+Down arrow "L"+Mousewheel backwards

Enlarge deflection diagram Reduce deflection diagram

"D"+Up arrow

Enlarge moment diagram Reduce moment diagram

"M"+Up arrow

Enlarge shear force diagram Reduce shear force diagram

"S"+Up arrow

Enlarge axial force diagram Reduce axial force diagram

"A"+Up arrow

"D"+Mousewheel forwards

"D"+Down arrow "D"+Mousewheel backwards

"M"+Mousewheel forwards

"M"+Down arrow "M"+Mousewheel backwards

"S"+Mousewheel forwards

"S"+Down arrow "S"+Mousewheel backwards

"A"+Mousewheel forwards

"A"+Down arrow "A"+Mousewheel backwards

Enlarge torsion "T"+Up arrow "T"+Mousewheel forwards diagram Reduce torsion diagram "T"+Down arrow "T"+Mousewheel backwards Enlarge buckling diagram Reduce buckling diagram

"B"+Up arrow

"B"+Mousewheel forwards

"B"+Down arrow "B"+Mousewheel backwards

Enlarge stress diagram "E"+Up arrow

"E"+Mousewheel forwards

75

SPACE GASS 12 User Manual Reduce stress diagram "E"+Down arrow "E"+Mousewheel backwards

76

Previous load case Next load case First load case Last load case

Page up Page down Home End

Previous filter Next filter No filter Last filter

Ctrl+Page up Ctrl+Page down Ctrl+Home Ctrl+End

Previous saved view Next saved view First saved view Last saved view

Shift+Page up Shift+Page down Shift+Home Shift+End

Repeat last command

Spacebar

Input Methods Input methods There are four main ways in which data can be input into SPACE GASS. Structure Wizard If your model resembles one of the standard structures available in the Structure Wizard then it is the easiest way to quickly generate your model in SPACE GASS. Even if it isn’t exactly what you want, you can then use the other graphical or datasheet tools to modify the generated model to your exact requirements. Datasheet Input Each component of the SPACE GASS model can be input, edited or viewed in a Datasheet. For example, there are datasheets for nodes, members, plates, section properties, member loads, masses, etc. Datasheets are an invaluable tool for viewing data or making changes, particularly using the multi-row editing tool. Graphical Input You can use Graphical Input to input or edit any parts of the structural data or load data in your model. This is a very powerful tool that has the advantages of allowing you to make large changes quickly and see your changes visually as you make them. Importing from Other Programs SPACE GASS is able to link to other programs and import the structural model in a wide variety of formats. Some of the commonly used CAD and BIM (building information management) programs that can be linked to SPACE GASS include Tekla Structures (XSteel), ProSteel, Microstation, Frameworks Plus, StruCAD, Revit Structure, Bentley Structural and AutoCAD. You can also import from SPACE GASS text files, CSV (comma separated value) files, DXF files, SDNF files, Microstran ARC files and MS-Excel files.

If you have your own program that generates the SPACE GASS data, if it can write the data into a SPACE GASS text file, CSV file or MS-Excel file in the correct format then it can be imported into SPACE GASS. If you wish to know the format of a CSV or MS-Excel file that is suitable for importing into SPACE GASS, the best way is to generate a small model in SPACE GASS using the structure wizard or some other method and then export it into a CSV or MS-Excel file and use resulting file as a pattern. The SPACE GASS text file format is fully explained in Text file format, but you can also generate a text file from SPACE GASS and use it as a pattern. The other formats are quite complex and are simply generated by the programs that you are importing your SPACE GASS model from. For more information, refer to "Linking to other programs". Common Database Each of the above data input methods operates on the same common database, therefore you can use any combination of methods to input your data. For example, you can use the 77

SPACE GASS 12 User Manual structure wizard to generate the basic frame geometry, then graphically edit the geometry and apply some loads, followed by opening up some datasheets to view the data and make further modifications to the structure or loads. When some data has been input, regardless of the amount or type, you can produce an output report on the screen or printer. In addition, regardless of which input method you use, the graphics display area displays the current state of the structural model graphically. A graphics hardcopy can also be produced at any time.

78

Linking to Other Programs Linking to other programs SPACE GASS can link to many other engineering, CAD and BIM (building information management) programs using a wide variety of links and file formats. Some of the commonly used CAD and BIM programs that can be linked to SPACE GASS include Tekla Structures (XSteel), ProSteel, Microstation, Frameworks Plus, StruCAD, Revit Structure, Bentley Structural and AutoCAD. Other programs that can import and/or export CIMSteel/2 (CIS/2) or IFC Step files can also be linked to SPACE GASS. These include STAAD, Risa-3D, SAP2000 ETABS, ROBOT, SmartPlant4D Structural and others Programs that can import and/or export DXF or SDNF files can also be linked to SPACE GASS, however only the basic geometry can be included in these formats. Details of the files that SPACE GASS can import/export are as follows. SPACE GASS Text File

ZIP File

CSV File

CIMSteel/2 (CIS/2) Step File

IFC Step File

This format is ideal for people who wish to write their own programs to generate the SPACE GASS data and then import it into SPACE GASS. The format of SPACE GASS text files is fully explained in "Text file input ". This format is still available but is essentially obsolete because the native SPACE GASS job files are actually ZIP files renamed from .ZIP to .SG. This format is also ideal for people who wish to write their own programs to generate the SPACE GASS data and then import it into SPACE GASS. It is a text file with the values separated by commas that can be written by many programs including MS-Excel. Useful for transferring models with many other CAD and building management programs such as Tekla Structures (XSteel), ProSteel, Microstation, Frameworks Plus, StruCAD, Revit Structure, Bentley Structural, AutoCAD, etc. This is a very comprehensive format that includes the structural and load data. Useful for transferring models with many other CAD and building management programs such as Tekla Structures (XSteel), ProSteel, Microstation, Frameworks Plus, StruCAD, Revit Structure, Bentley Structural, AutoCAD, etc. This is a very comprehensive format that includes the structural and load data.

79

SPACE GASS 12 User Manual DXF File

SDNF File

MS-Excel

MS-Word Microstran ARC

A drawing format text file invented for AutoCAD that many programs can import and export. It is a very good means of transferring drawings from SPACE GASS in the form of plans, elevations, cross sections and connection drawings into a CAD program. Because DXF is a drawing format, when transferring a structural model to another program, it is better to use the more comprehensive and specialized CIMSteel/2 and IFC Step file formats described above. This is a steel detailing neutral file format that has now been made obsolete by the much more advanced CIMSteel/2 and IFC Step file formats described above. It can contain the structural geometry and section property data and is still used by many programs. Microsoft Excel is a very powerful tool for generating data and can be used to quickly generate a structural model for importing into SPACE GASS. SPACE GASS can also export to Microsoft Excel. The data from a SPACE GASS model can be exported to a Microsoft Word document file. A format for importing Microstran models into SPACE GASS.

In order to import from or export to a SPACE GASS text file, CSV file, SDNF file, Microstran ARC file, MS-Excel file or MS-Word file, the procedure simply involves selecting the desired format from the Import or Export options in the File menu and then choosing a file name. Linking to other programs using the very comprehensive CIMSteel/2 (CIS/2) Step, IFC Step or Revit Structure transfer options are fully explained in the following sections.

80

Linking to Other Programs

CIMSteel/2 Step, IFC Step and Revit links Complete structural models can be imported into SPACE GASS or exported to other programs using the very comprehensive CIMSteel/2 (CIS/2) Step, IFC Step or Revit Structure transfer options. Each of these formats can contain the complete structural model, including loads and design data. They can be used to link SPACE GASS with programs such as Tekla Structures (XSteel), ProSteel, Microstation, Frameworks Plus, StruCAD, Revit Structure, Bentley Structural, AutoCAD and many others that use the CIMSteel/2 (CIS/2) Step or IFC Step formats. Revit Structure is slightly different to the other programs because in addition to communicating with SPACE GASS via the CIMSteel/2 or IFC links, it can also communicate via special import and export menu items that can be added to the Revit Structure "Tools" menu. The physical and analytical models The "physical" model includes all of the "visible" information such as the geometry of the beams, columns, braces, cables, trusses, struts, ties, walls, slabs and connections. It includes all the components that make up the model’s physical attributes. The "analytical" model includes the "visible" information too, but it also contains "hidden" information such as support conditions, member end releases, offset data, section and material properties, loads, load combinations, design data and analysis results. The other main difference with the analytical model is that, depending on the program you are importing from, the geometry may be somewhat idealised so that the centroids of members line up with the members they are connected to. For example, bracing members that connect to a beam-column connection do not often line up with the centroid of the beam-column connection in the real structure and in the "physical" model, however they may be adjusted to line up in the "analytical" model. Section name conversion files One of the major obstacles to successfully transferring data between programs is that there is no standard naming convention for section property names and hence every program uses slightly different names. To solve this problem, conversion files are used to convert the section names used by SPACE GASS to the names used by other programs. Conversion files are supplied with SPACE GASS for converting section names to Tekla Structures, Prosteel, Revit Structure and others. You can also make your own section name conversion files quite easily. A conversion file is simply a text file that contains a list of the SPACE GASS section names together with the library each section comes from and the name of the section that is used by the program SPACE GASS is communicating with. An extract from a typical conversion file is as follows: SG Name, SG library, Other name W21x101, US, W 21*101 W21x111, US, W 21*111 W21x122, US, W 21*122 You can see from the above example that the SPACE GASS name and the "Other name" are often very similar and sometimes only involve adding or removing spaces or changing from "x" to "*" or vice versa. 81


Standard section name conversion files are supplied with SPACE GASS for each of the SPACE GASS section libraries and each of the well-known programs that you may want SPACE GASS to communicate with. For example, Tekla Structures conversion files are supplied for each of the SPACE GASS section libraries. Similar sets of conversion files are also supplied for Revit Structure, Prosteel, etc. Creating custom section name conversion files You must first initiate a CIS/2 or IFC import or export from the File menu to display the following form.

Custom section name conversion files can then be created in either of two ways. 1.

You can create a custom conversion file that is a combination of some of the standard conversion files supplied with SPACE GASS. To do this you must first select a program name in the "Convert section names for" list box and then click the "Libraries" branch of the menu tree on the left and ensure that the SPACE GASS libraries from which the sections will be taken are listed in the "Library search order" box. You can then create the custom conversion file by clicking the "Create a custom section name conversion file" button.

2.

You can create a template for a custom conversion file that contains just the SPACE GASS section names and the libraries they come from, but not the "other program" names. To do this you must click the "Libraries" branch of the menu tree on the left and then ensure that the SPACE GASS libraries from which the sections will be taken are listed in the "Library search order" box. You can then create the template conversion file by clicking the "Create a template section name conversion file" button. To convert the template conversion file into a complete custom conversion file, you should edit the template file with a text editor such as Notepad and manually enter the "other program" names at the end of each line. You could also use MS-Excel, however when opening the file, you must specify that the file is comma delimited, otherwise each line will appear in

82

Linking to Other Programs just one cell.

Section name conversion files are stored in the SPACE GASS program folder (usually "c:\Program files\SPACE GASS\Exe"). Details of how to import and export using these links are explained in the following sections.

83


Import links You can import a CIS/2 or IFC Step file by selecting "Import - from CIMSteel/2 Step" or "Import - from IFC Step" from the File menu. When importing from Revit Structure, you can import a CIS/2 or IFC Step file created by it or you can select the "Send Model to SPACE GASS" item from the Revit Structure "Tools > External Tools" menu as explained in "Special Revit Structure Links". Even though the internal structure of CIS/2 step files and IFC step files are quite different, the importing procedure is the same and hence the following instructions apply to both.

The name of the file being imported is displayed in the "Data Filename" field and you can select another file by clicking on the button to the right of the input field. When importing, to ensure that the section names used by the source program are converted properly to SPACE GASS names, you should do the following: 1.

If you are linking with a standard program for which a section name conversion file exists, select it in the "Convert section names for" list box. If the name of the program you are linking with does not appear in the list, it simply means that there is currently no standard conversion file for that program. If so, you should select "Other". You can then create and use a custom conversion file or use one that you previously created as explained in "Creating custom section name conversion files" in the previous section. Alternatively, you can just skip the custom conversion file option and the section names will be imported or exported with no conversion.

2.

84

Click the "Libraries" branch of the menu tree on the left to display the section libraries form as shown below.


If you selected a program name in the "Convert section names for" list box in step 1 above, ensure that the "Use a standard section name conversion file" option is ticked. This will activate the section name conversion using the standard conversion files supplied with SPACE GASS. If you selected "Other" in the "Convert section names for" list box in step 1 above, and you have a custom conversion file that you want to use, ensure that the "Use a custom section name conversion file" option is ticked and that the name of the custom conversion file is in the "Conversion filename" field. If you wish to create a custom conversion file, follow the procedure in "Creating custom section name conversion files" in the previous section. If you wish to use a mixture of custom and standard conversion files, you can tick both the "Use a custom section name conversion file" and "Use a standard section name conversion file" options. In this case, SPACE GASS will try to convert the section name using the custom conversion file first and, if the name can’t be found there, the standard conversion files will be used.

3.

You also need to check that the appropriate SPACE GASS libraries are listed in the "Library search order" box. The "Library search order" box controls which SPACE GASS libraries will be used when the section names being imported are converted. If the name of a section being imported does not appear in one of the libraries listed in this box then it will not be converted. It is therefore important that you include enough libraries in the "Library search order" box to ensure that all the sections being imported have their names converted. You can include all libraries in the box, however this may slow down the import process slightly due to the increased number of libraries that have to be scanned. If a section name appears in more than one SPACE GASS library then the libraries higher up in the list will have priority.

You can choose which components of the model to import by expanding the "Import" branch of the menu tree on the left and then clicking "Nodes" or "Members" as shown below.

85


You can specify the starting node number or, if you leave it at zero, the imported nodes will be automatically numbered starting from the first available number. Nodes that are very close together can be merged into one, and the connecting members and plates adjusted to suit. If you select the "Adjust lower limits of node coordinates by" checkbox, SPACE GASS will find the node with the lowest coordinates and move it to the coordinates that you specify. The rest of the model will also be moved by the same amount.

You can specify the starting member and plate numbers or, if you leave them at zero, the imported members and plates will be automatically numbered starting from the first available number. Members that have an end very close to another member can be connected together. Similarly, members that cross each other within a specified distance can be subdivided and connected at the intersection point.

86

Linking to Other Programs A number of programs that generate CIS/2 and IFC Step files incorrectly mix radians and degrees when specifying member direction angles. If you are importing one of these nonstandard files and find that some members are rotated incorrectly, you can select the "Assume radians for all angular measurements" checkbox to correct the problem. For more information about the "Physical" and "Analytical" models, refer to "The physical and analytical models" in the previous section.

87


Export links You can export a CIS/2 or IFC Step file by selecting "Export - to CIMSteel/2 Step" or "Export - to IFC Step" from the File menu. When exporting to Revit Structure, you can export a CIS/2 or IFC Step file or you can select the "Update Model from SPACE GASS" item from the Revit Structure "Tools > External Tools" menu as explained in "Special Revit Structure Links". Even though the internal structure of CIS/2 step files and IFC step files are quite different, the exporting procedure is the same and hence the following instructions apply to both.

The name of the file being exported to is displayed in the "Data Filename" field and you can select another file by clicking on the button to the right of the input field. When exporting, to ensure that the section names used by SPACE GASS are converted properly to the names used by the destination program, you should do the following: 1.

If you are linking with a standard program for which a section name conversion file exists, select it in the "Convert section names for" list box. If the name of the program you are linking with does not appear in the list, it simply means that there is currently no standard conversion file for that program. If so, you should select "Other". You can then create and use a custom conversion file or use one that you previously created as explained in "Creating custom section name conversion files" in the previous section. Alternatively, you can just skip the custom conversion file option and the section names will be imported or exported with no conversion.

2.

88

Click the "Libraries" branch of the menu tree on the left to display the section libraries form as shown below.


If you selected a program name in the "Convert section names for" list box in step 1 above, ensure that the "Use a standard section name conversion file" option is ticked. This will activate the section name conversion using the standard conversion files supplied with SPACE GASS. If you selected "Other" in the "Convert section names for" list box in step 1 above, and you have a custom conversion file that you want to use, ensure that the "Use a custom section name conversion file" option is ticked and that the name of the custom conversion file is in the "Conversion filename" field. If you wish to create a custom conversion file, follow the procedure in "Creating custom section name conversion files" in the previous section. If you wish to use a mixture of custom and standard conversion files, you can tick both the "Use a custom section name conversion file" and "Use a standard section name conversion file" options. In this case, SPACE GASS will try to convert the section name using the custom conversion file first and, if the name can’t be found there, the standard conversion files will be used.

You can choose which components of the model to export by clicking the "Export" branch of the menu tree on the left.

89

SPACE GASS 12 User Manual The normal procedure is to export the analytical model because, as well as the geometric information, it contains "hidden" information such as support conditions, member end releases, offset data, section and material properties, loads, load combinations, design data and analysis results. However, if you are exporting to a program that requires the physical model then you should select it. Note that when exporting from SPACE GASS, the geometric information in the physical and analytical models is the same. For more information about the "Physical" and "Analytical" models, refer to "The physical and analytical models" in the previous section.

90


Special Revit Structure links Revit Structure is slightly different to the other programs because there are two ways to link it to SPACE GASS. In addition to being able to communicate with SPACE GASS via the CIMSteel/2 and IFC Step file links, Revit Structure can be configured to create SPACE GASS jobs directly and also update the Revit model from them. The advantage of using the direct Revit Structure link over the CIMSteel/2 and IFC links is that after you have transferred the model to SPACE GASS, you can import the section property and steel design changes back into Revit Structure without completely replacing the Revit Structure model. The advantage of the CIMSteel/2 and IFC Step file links is that you can start with a SPACE GASS model and transfer it into Revit Structure to create a Revit model from scratch. You can’t do this with the direct Revit Structure link. Of course, you can use a combination of methods. You could start with a SPACE GASS model, export it using CIMSteel/2 or IFC to create a new Revit Structure model, add to the model in Revit Structure and then export it back to SPACE GASS using the direct Revit Structure link. Setting up the direct link between SPACE GASS and Revit Structure You can add the special SPACE GASS items to the Revit Structure "Tools" menu by running the RevitSpaceGassLink.exe file in the SPACE GASS program folder (usually "c:\Program files\SPACE GASS\Exe"). The program will attempt to find the SPACE GASS and Revit Structure program folders and then display them in the following form.

If either field doesn’t display a folder name with "(file found)" at the end, you will have to click the appropriate browse button at the right of the field to select the program folder manually. Once both folders have been identified correctly you can click the Ok button and the SPACE GASS items will be automatically added to the Revit Structure "Tools" menu. Transferring from Revit Structure To create a complete SPACE GASS model from Revit Structure, click the "Send Model to SPACE GASS" item from the Revit Structure "Tools" menu.

91


When exporting to SPACE GASS, you have full control over units, connections between beams and columns, loads, member offsets, specification of tension-only members, section names, etc. If the names of sections in your Revit Structure model are different to the names used in the SPACE GASS section libraries, you can use (or set up your own) section name conversion file that converts the Revit Structure names to the SPACE GASS names. For more information, refer to "Creating custom section name conversion files" in "CIMSteel/2 Step, IFC Step and Revit links". Transferring to Revit Structure When the SPACE GASS analysis and/or design is complete, you can update the Revit Structure model by clicking the "Update Model from SPACE GASS" item from the Revit Structure "Tools" menu.

92


When importing from SPACE GASS you can elect to incorporate steel design data into the Revit Structure model. This is then retained in Revit Structure and returned to SPACE GASS the next time you export a model to SPACE GASS from Revit Structure.

93


DXF links The DXF file format is a text format invented for AutoCAD that many programs can import and export. Because DXF is essentially a drawing format rather than for engineering models, it is limited to the basic structural geometry when used to transfer a structural model. For this reason, transferring a structural model is best done using the CIMSteel/2 (CIS/2) Step or IFC Step file formats or the Revit links which are very comprehensive and can include loads. The DXF format is, however, a very good means of creating drawings in the form of plans, elevations, cross sections and connection drawings for transferring into a CAD program. Details of how to import and export DXF files are explained in the following sections.

94


Importing DXF files You can import a DXF file by selecting "Import - from DXF" from the File menu. When importing, SPACE GASS interprets each discrete line in a CAD drawing as a member. This has two ramifications that you will need to consider. 1. CAD programs do not know that intersecting lines need to be segmented into submembers with nodes at the intersection points. For example, if you drew the top and bottom chords of a truss with just two lines adding the struts and braces as separate lines, SPACE GASS would consider that the chords are not connected to the web members except at the chord ends. You must ensure every member that you want in the SPACE GASS model is drawn as a separate line in the CAD program. If you draw a line in the CAD program which continues past a node then the member will not be connected to that node in the SPACE GASS model. 2. You shouldn’t read a DXF file, created with full member geometry, back into SPACE GASS (it interprets each member flange and web line as an individual member).

Note that SPACE GASS only interprets LINE, 3DLINE and POLYLINE entities as geometry when importing a DXF file. All other entity types are ignored. It is usually much quicker and more efficient to draw the structure directly in SPACE GASS rather than drawing it in your CAD program and importing it into SPACE GASS. This is because SPACE GASS knows it is dealing with a structure and not just lines in a drawing.

95


Exporting DXF files There are two types of DXF files that can be exported from SPACE GASS. 1.

Elevations, plans, cross sections and member schedules.

2.

Steel connection drawings.

Exporting elevations, plans, cross sections and member schedules You can export elevations, plans, cross sections and member schedules by selecting "Export – to DXF" from the File menu.

Full geometry You can elect to simply export a wireframe drawing that consists of lines along the centrelines of each member, or you can also include the full member geometry which shows the actual member shapes including flanges and webs, etc. Drawings that include the full member geometry can have the geometry lines shortened by a distance factor that you specify in the General Configuration form at each end of the member so that intersecting members do not run into one another. Member schedule Selecting this check box causes a member schedule to be included in the drawing. Z axis vertical AutoCAD and some other 3D CAD programs assume that the Y-axis is vertical for 2D drawings, while the Z-axis is vertical for 3D drawings. 96


If this check box is selected then the global Z-axis is made vertical in the drawing, otherwise the Y-axis is vertical. Label members Members can be unlabelled, or labelled with the member names, member marks or both. Draw with By choosing 3DLINEs or FACES you can generate a full 3D drawing, or by choosing 2DLINEs you can limit the drawing to just 2D views, elevations, plans or cross sections of the structure. Note that FACEs support hidden line removal and shading while 3DLINEs do not. A 3D drawing complete with full member geometry is very useful for visualizing how the structure fits together and for checking whether members clash with each other or not. Similar 3D drawings with hidden line removal can also be viewed directly in SPACE GASS without having to go to a CAD program (see also View rendered model). Because almost all structural drawings are made up predominantly of 2D plans, elevations and details, the ability of SPACE GASS to produce 2D drawings of the frame is one of the most useful aspects of being able to export DXF files. SPACE GASS allows you to create a series of 2D vertical or horizontal "slices" at any position through a 3D frame and have them exported to CAD as cross sections, elevations or plans. These 2D drawings can contain the full member geometry complete with dashed and dotted hidden lines. It is then a simple matter for a draftsperson to use a CAD package, such as AutoCAD, to add connections, notation, etc. and complete the structural drawing. 2D drawing plane If you have specified a 2D drawing by choosing 2DLINEs in the "Draw with" combo box, you must choose a 2D drawing plane here. 2D drawing limits If you have specified a 2D drawing, then you must nominate upper and lower drawing plane limits. The limits will be along the global axis at right angles to the 2D drawing plane. Any members that lie between the two limits will be included in the drawing. Scale You can scale the drawing up or down with this field. For example, a scale of 10 causes the drawing dimensions to be reduced by a factor of 10. Units for the DXF drawing file are the same as those used in SPACE GASS. Title Typing a title into this field causes it to appear at the bottom of the drawing. DXF layer names Layer names can be any names of up to 8 characters. AutoSKETCH requires layer names to be integers from 1 to 10 in all cases. It is recommended that you configure your CAD software so that the hidden line layer uses dashed or dotted lines. This ensures that they can be easily distinguished from visible geometry lines. You can specify that the layers should be section-specific for centerlines, full geometry and/or text. This means that each member type will have its own layer rather than the entire frame 97

SPACE GASS 12 User Manual just going into a single layer. You can then set your CAD software so that each layer has a different color, making identification of the various section types very easy.

Exporting steel connection drawings During or after a steel connection design, you can create fully detailed and annotated drawings of the connections and export them to DXF drawing files in either of two ways. 1.

Enable the "Generate drawings for a CAD system" option at the beginning of the connection design phase (see also Running a steel connection design). This causes a DXF drawing file to be created for every connection designed.

2.

Click the toolbar button after the connection design phase to view the connection drawings graphically and then selectively produce DXF files from there (see also View steel connection drawings).

Using either method, the final result is the same. You can control the drawing layer names by setting them in the SPACE GASS configuration data. An example of a steel connection drawing produced automatically by SPACE GASS is shown as follows.

98

Linking to Other Programs SPACE GASS connection detail

99

Modelling the Structure Modelling the structure Before a frame can be modelled and analysed with a program such as SPACE GASS, it must first be idealised and modelled mathematically. The most popular mathematical model uses the concept of nodes connected by elements of a finite size (finite elements). SPACE GASS requires that frames are represented by nodes connected by members, cables or plates. Such nodes are generally free to move and rotate in space. Practical structures, however, are connected to a footing in some way, and so node restraints must be applied which limit the movement of selected nodes. The relative movement between nodes connected by a member, cable or plate is a function of the section and material properties of that element. Loads can be mathematically represented in the model and can be applied elements. Such loads include all of the normal force and moment type loads, in addition to load inducers such as prescribed displacements and temperature differentials. A single analysis can consider numerous load cases, each of which may contain many different load types. During the analysis phase, all unrestrained node displacements (degrees of freedom) are calculated for each load case. Element forces and moments are then determined from the relative movement of the nodes they are connected to and, finally, reactions are calculated by equating element reactions at each restrained node. If the analysis selected is non-linear, SPACE GASS does an initial linear analysis and then modifies the stiffness matrix for each member based on the previous analysis node displacements and member axial forces. It then re-analyses the structure for the modified member stiffness and continues iterating the analysis phase in this way until convergence is achieved. Note that because the plate elements are linear elements at this stage, their stiffness is not modified during the non-linear analysis iterations.

101


Coordinate systems The geometry of a structural model is referenced by a set of global XYZ axes. Each member and plate element also has its own set of local xyz axes so that items such as section properties and local loads can be more easily referenced. All axes are right hand orthogonal. This means that if you are looking at the XY plane with the Y-axis pointing upwards and the X-axis pointing to the right, the Z-axis points towards you as shown below. Global Axes The shape and position of a structure in space is defined by a set of global axes (X,Y,Z). All node coordinates, for example, are input relative to the global axes system. The global XZ plane is assumed to be horizontal, while the global Y-axis points vertically upwards. Note that although SPACE GASS assumes that the Y-axis is vertical by default, it can be configured to set the Z-axis to vertical. This is done via the Viewpoint tool.

Global Axes

Member Axes The local axes for a member have their origin at node A and are defined as follows: 1. The x-axis lies along the axis of the member and points from node A to node B. 2. The local y-axis is normal to the local x-axis and points in the same general direction as the global Y-axis. It is orientated such that the local xy-plane is parallel to the global Y-axis. 3. The local z-axis is orthogonal with x and y. For members that have their longitudinal axis parallel to the global Y-axis, rule 2 is undefined and hence, for these members, the local z-axis points in the same direction as the global Z-axis. 4. If a direction angle, node or axis is defined then the member is rolled about it’s longitudinal x-axis by the direction angle or, if a direction node or axis is defined, by an amount such that the local y-axis is aligned with the direction node or axis as shown below.

102

Modelling the Structure

Member Local Axes

Member Direction Angle

Member Direction Node

103


Member Direction Axis

If you are unsure of the orientation of the local axes for a particular member, you can display them graphically (see also View local axes). Plate Axes The local axes for a plate have their origin at the centre of the plate and are defined as follows: 1. The x-axis is in the plane of the plate and is parallel to the line joining node A and node B. 2. The local y-axis is also in the plane of the plate and is normal to the local x-axis. 3. The local z-axis is normal to the plane of the plate and is orthogonal with x and y. 4. If a direction angle, node or axis is defined then the local axes are rotated about the plate’s normal z-axis by the direction angle or, if a direction node or axis is defined, by an amount such that the local y-axis is aligned with the direction node or axis as shown below. Note that defining a direction angle, node or axis affects the orientation of the plate’s axes but not the orientation of the plate itself.

Plate Local Axes

104


Plate Direction Angle

Plate Direction Node

105

SPACE GASS 12 User Manual Plate Direction Axis

If you are unsure of the orientation of the local axes for a particular plate, you can display them graphically (see also View local axes).

106


Sign conventions Items which act along or about an axis are considered to be positive when they act along or about the positive axis direction. Positive rotations conform to the right hand screw rule shown as follows.

Right Hand Screw Rule

Applied loads have their sign determined by the axes system in which they are referred. Most types of member and plate loads can be specified in either the global or local system, however node loads and self weight are always referenced by the global system. Node displacements are positive if they displace along or around the positive global axis directions. External reactions are positive if they act along or around the positive global axis directions. Member Actions Member actions follow the sign conventions as follows.

Member Forces and Moments

Positive axial forces cause compression in the member. Positive moments cause compression on the positive axis side of the member.

107


Channel and angle sections have their flange toes pointing in the direction of the local z-axis. Positive y-axis moments therefore cause the flange toes to go into compression. Positive shears cause the node A end of the member to translate in the direction of the positive axis with respect to the node B end. Positive torsions cause the node A end of the member to rotate anti-clockwise with respect to the node B end when observed from the node B end. Plate Actions Plate actions follow the sign conventions as follows.

Plate Forces

108

Modelling the Structure Plate Moments

When calculating the design moments for reinforced concrete slabs, the twisting moment Mxy must be combined with the normal bending moments Mx and My. The WoodArmer method is commonly used for this and is explained in "Bending Moments in Reinforced Concrete Slabs" below.

Plate Stresses

Note that plate elements have no rotational stiffness about their local z-axis. This means that there is effectively a rotational pin connection between the plate and its corner nodes about the axis normal to the plate. Positive moments cause compression in the top (positive z-axis) face of the plate. Plane Stress Three dimensional objects subjected to loads generally have three principal stresses, however in structural elements where one dimension is very small compared to the other two (ie. plate elements), one of the three principal stresses is zero and a state of "plane stress" is said to exist. In this case, the stresses are negligible with respect to the smaller dimension as they are not able to develop within the material and are small compared to the in-plane stresses. Principal Stress For plates subjected to plane stress, there are two principal stresses acting in the principal axis directions. The angle between the principal axes and the local x and y axes is called the principal angle. The principal stresses can be calculated from x, y and xy using Mohr circle theory as follows. 1 (max) = (x + y)/2 + SQRT((x - y)2/4 + xy2)  (min) = (x + y)/2 - SQRT((x - y)2/4 + xy2) xymax = ( - )/2 109

SPACE GASS 12 User Manual  = Tan-1(2xy/(x - y))/2 where x, y and xy are the membrane and shear stresses in the local axis directions (as per the above diagrams), 1 and 2 are the principal stresses, xymax is the maximum shear stress and  is the principal angle. von Mises Stress Richard von Mises (an eminent Austrian scientist who worked on solid mechanics, fluid mechanics, aerodynamics, aeronautics, statistics and probability theory) found that, even though none of the principal stresses exceeds the yield stress of the material, it is possible for yielding to result from the combination of stresses. The von Mises criteria is a formula for combining these principal stresses into an equivalent stress, which is then compared to the yield stress of the material. The yield stress is a known property of the material and is usually considered to be the failure stress. The equivalent stress is often called the "von Mises Stress" as a shorthand description. It is not really a stress, but a number that is used as an index. If the von Mises stress exceeds the yield stress, then the material is considered to be at the failure condition. The von Mises stress can be calculated from the principal stresses according to: vm = SQRT(((1 – 2)2 + 12 + 22)/2) where 1 and 2 are the principal stresses and vm is the equivalent or "von Mises" stress. Bending Moments in Reinforced Concrete Slabs When evaluating the design moments for a reinforced concrete slab, the twisting moment Mxy must be taken into account in addition to the normal bending moments Mx and My. Mxy contributes a moment effect to both the principal bending directions x and y. Using the Wood-Armer method, the design moments Mx* and My* can be determined as follows: To design bottom reinforcement (ie. calculate moments that cause tension in the bottom face): Mx* = Mx + | Mxy | My* = My + | Mxy | If either of Mx* or My* from the above calculations are < 0 then If Mx* < 0 then Mx* = 0 and My* = My + | Mxy2/Mx | If My* < 0 then My* = 0 and Mx* = Mx + | Mxy2/My | To design top reinforcement (ie. calculate moments that cause tension in the top face): Mx* = Mx - | Mxy | My* = My - | Mxy | If either of Mx* or My* from the above calculations are > 0 then If Mx* > 0 then Mx* = 0 and My* = My - | Mxy2/Mx | If My* > 0 then My* = 0 and Mx* = Mx - | Mxy2/My | Further information can be found by searching for "Wood-Armer" on the Internet or at web sites such as http://www.scribd.com/doc/76706580/Slab-Design-by-Wood-Armer-Method or http://www.scribd.com/doc/51463621/Wood-Armer

110


Ill-conditioning and instabilities The most common analysis errors are caused by structures that are not correctly conditioned or stabilised. Ill-conditioning commonly occurs when frames contain members of widely varying stiffness’s. When a very stiff member is connected to a very flexible member and their stiffness matrices are assembled into the structure stiffness matrix, some of the stiffness terms of the flexible member can be completely lost due to their insignificance in comparison with the stiffness terms of the stiff member. Hence, the flexible member is not completely represented and ill-conditioning occurs. SPACE GASS contains an algorithm which checks for possible ill-conditioning and displays warning messages if appropriate. Generally, these messages appear well before illconditioning actually occurs. They do, however serve to highlight structures which are close to being ill-conditioned. If after the analysis, the sum of the reactions equals the sum of the applied loads then it can be assumed that the frame is well conditioned. Instabilities occur when one or more nodes are free to translate or rotate without resistance from the frame. Sometimes unstable structures are very easy to detect, such as when restraints have not been applied or when an obvious collapse mechanism is possible. Instabilities are often very subtle and difficult to isolate. For example, if an unrestrained node has a pinned connection to each of its connecting members then it would be free to rotate and an instability would result. This type of instability can be hard to detect because it only affects one node in the structure. True trusses must therefore have every rotational degree of freedom restrained. Sometimes highly ill-conditioned frames can also be interpreted as being unstable by the program. Another common type of instability occurs when a group of members connected end-to-end in a straight line are free to rotate about their longitudinal axis. The instability occurs because during the analysis the program is unable to determine the amount of rotation of the intermediate nodes. Some instabilities cannot be detected by a static analysis, and you should therefore be wary of results that contain very large deflections or deflections that occur in the wrong direction. However most instabilities can be detected by a buckling analysis and are identified by very low buckling load factors. If you get buckling load factors that are below the minimum allowable value (eg. shown as "<0.001" when the minimum allowable value is 0.001), this could indicate an instability problem rather than a buckling problem. It is even more likely to be an instability problem if the low buckling load factors occur in every load case. If the model contains instabilities, the buckling analysis may, in some cases, give invalid results. In the absence of instability or buckling messages from the static analysis, you should always check the deflections to see if they are excessive or not. Excessive deflections are sometimes the only indicator of instabilities. There are no hard and fast rules to follow in the detection of conditioning and stability problems, however if the structure is clearly drawn and examined, the problem usually becomes evident to any moderately experienced user. 111


SPACE GASS is now able to automatically rectify some instabilities caused by nodes that are free to rotate or translate in one or more directions without resistance from interconnecting members, restraints or constraints. For more information, refer to "Stabilize unrestrained nodes" in Running a static analysis.

112

Project Data Project data This chapter describes in detail each type of data that can be included in the analysis model.

This chapter does not include design data (see also "Steel member design", "Steel connection design" and "Concrete column design"). See also Input methods. See also Output. See also Print graphics.

113


Units

SPACE GASS can handle a variety of different unit sets. The units do not need to be consistent or even belong to the same system (ie. you can mix units from Metric and Imperial). You can quickly select standard Imperial or Metric by clicking the "Imperial" or "Metric" buttons and then make further individual changes as required. If the "Convert the current job for any unit changes" box is checked then all of the data in the current job will be converted in accordance with the units changes you made. If the box is not checked then the units will change but none of the job data will be converted. If the "Save the above units as the default for new jobs" box is checked then SPACE GASS will use the selected units as the default every time you start a new job in the future.

If you are entering data and are not sure what the correct units are for that particular type of data, you should either (a) select the datasheet (from the datasheets button on the top toolbar) for the particular type of data you are entering and observe the units displayed at the bottom-right of the datasheet or, (b) produce an output report and observe the units displayed next to each section heading. ! IMPORTANT NOTE ! Before accepting any output from SPACE GASS, please check that all of the input and output data conforms to the units you have selected. You can do this most conveniently by producing a full output report and observing the units that are shown next to the heading in each section of the report. ! IMPORTANT NOTE ! If you change units for any or all data types after having input some data and you want the data to be converted, then you must ensure that the option to "Convert the current job for any unit changes" is checked. Otherwise the data will not be converted automatically.

114

Project Data

See also The structure menu. See also Initiator.

115


Job details and attachments This tool allows you to specify headings for your job and attach other files that you want to embed and save with the job. Headings

Project heading Allows you to describe the project. Job heading Allows you to describe the job. Designer Identifies you as the designer. Notes Allows you to describe the job in more detail.

Attachments You can attach external documents, drawings, spreadsheets and other files to your job that are then saved and embedded into the main .SG job file. They can be added, opened or extracted using the form shown below.

116

Project Data

See also The structure menu. See also Headings text.

117


Node data

Nodes are used to define the geometry of the structure in 3D space, and to mark the start and end points of members in the model. There are six possible displacements (degrees of freedom) per node in a 3D frame. They are translation along, and rotation about, X,Y, Z. Node The node numbering order is of no consequence and successive node numbers do not have to be sequential. For example, a straight beam with five nodes could just as easily be numbered 24,8,2,13,99 as 1,2,3,4,5. It is possible to leave gaps in the numbering sequence to allow for nodes which might be inserted later.

While the node numbering sequence doesn’t effect the results it is easier to interpret the results of an analysis if a logical numbering sequence has been used.

You can renumber nodes at any stage by using the graphics renumbering facility (see also Renumber). X, Y and Z coordinates Global coordinates of the node that may be positive or negative. Dummy nodes These are nodes that are not connected to any members. They are useful as direction nodes or reference points. See also Node restraints. See also Master-slave constraints. See also Members. See also Nodes text. See also Datasheet Input. See also Node properties. See also Draw.

118

Project Data

Member data

Members represent the actual beams, columns, ties, struts, cables, braces, etc. in the real structure. They must be prismatic and must be connected to a node at each end. Member The member numbering order affects the analysis frontwidth, however this is of no consequence if the wavefront optimiser is used. The graphical renumbering tool also means that the initial member numbering order is unimportant because it can be easily changed at any time. Successive member numbers do not have to be sequential. Type Choices are:

Normal, Tension-only, Compression-only, Cable.

While in tension, tension-only members act identically to normal members with axial, flexural, torsional and shear capacity. However, if they go into compression then they are automatically disabled and act as if they have been removed from the model. Members such as tension bracing and slender ties fall into this category.

Slender members that rely on axial tension to resist lateral loads applied to them should be modelled as cables rather than as tension-only members! While in compression, compression-only members act identically to normal members with axial, flexural, torsional and shear capacity. However, if they go into tension then they are automatically disabled and act as if they have been removed from the model. This type of member is useful in situations such as where a support member resists download loads by bearing on a footing but is unable to resist any uplift. In both tension-only and compression-only cases, the program does an initial analysis and then scans for tension-only members that have gone into compression, and compression-only members that have gone into tension. If any of these are found they are disabled and the structure is re-analysed. This process continues until all tension-only members are in tension and all compression-only members are in compression. Note that disabled members are sometimes re-enabled if their axial force reverses sign during the iteration process.

During a dynamic analysis, tension-only and compression-only members are treated as normal members that can take tension and compression.

119


See also Tension-only and compression-only effects. Cable members use axial tension only to resist lateral loads. They have no flexural, torsional or shear capacity, and so to avoid instabilities you must restrain all rotational degrees of freedom for nodes connected to cable members which are not rotationally fixed to other members. Cable end fixities of FFFFFF, FFFFFR, FFFFRR, FFFRRR all give the same results. Cables that aren’t laterally loaded are treated as tension-only members which become disabled if they go into compression. Laterally loaded cables sag instead of taking compression.

Cable members cannot be included in a dynamic analysis. See also Cable members. Cable length If the member type is "Cable" then an unstrained cable length can be specified to allow for cable sag when the cable length is different to the chord length (as follows). A zero cable length indicates that the unstrained cable length is equal to the chord length. Chord length The chord length is the straight line distance between the member ends Note that a member’s chord length may not be equal to the distance between it’s end nodes if offsets exist for that member. Using a direction angle, node or axis If a direction angle, node or axis is defined then the member is rolled about it’s longitudinal xaxis by the direction angle or, if a direction node or axis is defined, by an amount such that the local y-axis is aligned with the direction node or axis as shown below. Note that the three member orientation members are mutually exclusive. Hence, setting one of them to a desired value causes the other two to be disabled.

Member Local Axes

120

Project Data Direction angle The direction angle (degrees), also called the skew angle, allows you to roll the member (with its local axes) about it’s longitudinal axis. It is normally set to zero so that the member local y-axis lies in a vertical plane.

Member Direction Angle

Direction node Selecting a direction node aligns the local xy-plane with the nominated node. A direction node can be a normal node or a dummy node (one which is not connected to any members).

Direction Node

Direction axis Choices are:

X axis, Y axis, Z axis, -X axis, -Y axis,

121

SPACE GASS 12 User Manual -Z axis, N/A. Selecting a direction axis aligns the local xy-plane with the nominated axis (eg. -Z axis selected in the diagram as follows).

Direction Axis

If you are unsure of the orientation of the local axes for a particular plate, you can display them graphically (see also View local axes). Node A and B The two end nodes connected to each member are referred to as node A and node B. Node A is considered to be at the start of the member and any external loads applied to the member are located by their distance from node A. Node A cannot be equal to node B, however there are no restrictions relating to node A being numerically bigger than node B or vice-versa. End fixity A member may be released or fixed to its end nodes with varying degrees of fixity. Member end fixity is referenced by the local axes system and there are six possible components at each end which may be fixed or released. These components are specified by a six character code corresponding to translational fixity along x, y and z and rotational fixity about x, y and z respectively. The letter "F" represents fixed and "R" represents released. Thus, as an example, a pin ended truss member with no rotational end fixity in a 3D frame could be modelled using a fixity of "FFFFRR" at each end (or FFFRRR if the torsions are also released), while a pin ended truss member in a 2D frame could have fixities of "FFFFFR". Members with fully fixed ends would have fixities of "FFFFFF". You can also specify a spring stiffness, allowing you to model a semi-rigid joint. The letter "S" represents a spring stiffness, applicable to rotation about the local y or z axes of the member. If you specify a spring stiffness in the fixity code you will also need to enter a corresponding stiffness in the y/z stiffness fields. ! IMPORTANT NOTE ! Member end fixities should not be confused with node restraints. Member end fixities specify how members are connected to their end nodes, while node restraints specify how nodes are connected to the footings or other supports. Note that completely rigid frame members should have member end fixities of "FFFFFF" regardless of whether the frame has pin based supports or not.

122

Project Data

Section The section property number references a particular member cross section from the section property data. Thus, members with identical section properties would have the same section property numbers. The current section property for the members selected is displayed in this field. If no section property has been chosen, or if more than one section property applies to the selection, this field will be blank. The source is displayed along with an indication of whether the section has been flipped and what type of angle section was chosen (if appropriate). You can change the section property by entering another section property number. If this number corresponds with a section which has already been defined, the corresponding properties will be displayed. All of the members selected will have this property applied to them. Material The material property number references a particular material from the material property data. Thus, members with identical materials would have the same material property numbers.

For full details of the forces and moments in members, refer to "Sign conventions". See also Section properties. See also Material properties. See also Member offsets. See also Members text. See also Datasheet Input. See also Member properties. See also Draw.

123


Plate data

A mesh of plate elements can be used to represent walls, slabs, plates, etc. in the real structure. Plate elements can be triangular or quadrilateral with a node at each vertex. They can be connected at their nodes to other non-plate elements such as beams, columns, cables, etc. Plate The plate numbering order affects the analysis frontwidth, however this is of no consequence if the wavefront optimiser is used. The graphical renumbering tool also means that the initial plate numbering order is unimportant because it can be easily changed at any time. Successive plate numbers do not have to be sequential. Type Each plate can be specified as thick (using Mindlin plate theory – Ref. 19,20,21) or thin (using Kirchoff plate theory – Ref. 22,23). Transverse shear is not considered for Kirchoff plate theory and for the vast majority of applications in structural engineering we would recommend that Mindlin plate theory be used. Direction angle, node, axis By default, a plate’s local axes are such that x and y are in the plane of the plate and z is normal to the plate. The x-axis is aligned with a line joining nodes A and B and the y-axis is orthogonal with respect to x and z. The direction fields allow you to rotate the x and y axes about the plate’s normal z axis. The purpose for this is to control the axes for which the output results apply.

Plate Axes

It is recommended that for the plate elements in a surface, you align all their in-plane axes in the same direction rather than having them orientated randomly. For circular plates, you may elect to have all of the axes aligned in the same direction or, alternatively, you could align them radially or tangentially depending on which type of output you require.

124

Project Data

If the plate axes are orientated randomly then the results will be for different axis directions and they will be difficult to compare. It will also be difficult to produce meaningful contour diagrams if the plate axes are not aligned. The Align plate axes tool can be used to quickly align the axes for a selection of plate elements. It will also optionally reverse the normal z-axis of some plate elements if they are not all pointing in the same direction. You can also use the Reverse plate direction tool as an alternative way of reversing the normal z-axis.

Direction Angle

Direction Node

125


Direction Axis

If you are unsure of the orientation of the local axes for a particular plate, you can display them graphically (see also View local axes). Actual thickness This is the actual thickness of the plate and is used to calculate it’s self weight and self-mass if they have been specified. The thickness should be limited to around 15% of the in-plane plate dimensions for Mindlin plates and around 5% for Kirchoff plates. The plate dimensions relate to the overall plate size and not the element size. Membrane thickness This is used to calculate the membrane stiffness of the plate and is usually the same as the actual thickness. The membrane stiffness terms are the ones that affect Fx, Fy and Fxy as shown below.

126

Project Data Bending thickness This is used to calculate the bending stiffness of the plate and is usually the same as the actual thickness. The moment of inertia per unit length of the plate is taken as Tb3/12, where Tb is the bending thickness. The bending stiffness terms are the ones that affect Mx, My and Mxy as shown below.

When calculating the design moments for reinforced concrete slabs, the twisting moment Mxy must be combined with the normal bending moments Mx and My. The WoodArmer method is commonly used for this and is explained in "Sign conventions". Shear thickness This is used to calculate the transverse shear stiffness of the plate and is only used for Mindlin (thick) plate theory. For a uniform plate the shear thickness should be approximately Ta*(5/6) to be consistent with Mindlin thick plate theory, where Ta is the actual plate thickness. The transverse shear stiffness terms are the ones that affect Vxz and Vyz as shown below.

127


Offset Plates can be offset along their normal z-axis. This may be required to line them up with other interconnecting elements such as other plates or members.

Material Material property number references a particular material from the material property data. Thus, plates with identical materials would have the same material property numbers.

For an accurate analysis, plates must be properly meshed into elements that are a suitable size, shape and pattern. For more information, refer to the Mesh tool.

For full details of the forces, moments and stresses in plates, refer to "Sign conventions".

See also Material properties. See also Plates text. See also Datasheet Input. See also Plate properties. See also Draw.

128

Project Data

Node restraint data

Node restraints are used to model the structure’s supports. They are sometimes referred to as boundary conditions. Unrestrained nodes are generally free to move along or about any axis direction, however practical structures must be restrained to a footing in some way, otherwise instabilities would occur. Nodes can be restrained about one or all of their six degrees of freedom and such a restraint may take the form of a fixed restraint or a flexible restraint. If a degree of freedom is given a flexible restraint then a spring stiffness must also be input. Fixing a degree of freedom has the effect of immobilizing that node movement, while specifying a flexible restraint causes the node movement to be a function of the spring stiffness. Node restraints are specified by a six character code corresponding to restraints along X, Y and Z and about X, Y and Z respectively. "F" represents fixed, "R" represents released and "S" represents spring (or flexible). "D" restraints are no longer supported and "F" should be used instead. For example, a pin-based support that prevents all translations but allows the node to rotate about X, Y or Z would have a restraint code of FFFRRR. Alternatively, a roller support that allows the node to move in the X direction only and rotate about X, Y or Z would have a restraint code of RFFRRR. A fully built-in (encastre) support would have a restraint code of FFFFFF. A restraint that prevents movement in the Z direction while allowing all other movements and rotations would have a restraint code of RRFRRR. ! IMPORTANT NOTE ! Member end fixities should not be confused with node restraints. Member end fixities specify how members are connected to their end nodes, while node restraints specify how nodes are connected to the footings or other supports. Note that completely rigid frame members should have member end fixities of "FFFFFF" regardless of whether the frame has pin based supports or not. General restraint The general restraint facility allows you to apply a restraint to all otherwise unrestrained nodes. For example, if you have a frame with two pin based supports and you want to prevent all translations in the Z direction for all of its other nodes, you could apply restraints of FFFRRR to the two support nodes and specify a general restraint of RRFRRR.

129

SPACE GASS 12 User Manual In order to input a general restraint, you simply apply the desired restraint to any unrestrained node and then tick the "General" box (or select "Yes" in the General Restraint column if you are using a datasheet). Using a general restraint saves data entry time and reduces the quantity of printed output. Note that output reports only show the general restraint code on one node, even though the analysis has assumed that it applies to all unrestrained nodes. ! IMPORTANT NOTE ! The general restraint facility should be used with great care and only if you are absolutely sure of the effect it has on your model! If you apply a general restraint early in the development of your model and then forget that it exists at some later stage when it is no longer appropriate, you could be over-restraining your model. This could happen if nodes are added that shouldn’t get the general restraint. It could also happen if you initially use a general restraint to prevent all out-of-plane movements in a 2D frame for example and then extend the frame to 3D and forget to remove the general restraint. X, Y and Z axial stiffnesses Axial spring stiffness for degrees of freedom restrained with "S". Axial spring stiffnesses must always be greater than zero. When modelling the elastic properties of soil as a spring support, the spring stiffness is based on the modulus of subgrade reaction of the soil. This is a notoriously difficult parameter to get an accurate figure for. The following typical values of the modulus of subgrade reaction (to be used as a guide) are extracted from J. E. Bowles, "Foundation analysis and design", McGraw Hill 4th Edition, 1988. Soil Type Loose sand: Medium dense sand: Dense sand: Clayey medium dense sand: Silty medium dense sand: Clayey soil with qu < 200 kPa: Clayey soil with qu in range 200 to 400 kPa: Clayey soil with qu > 800 kPa:

Modulus of Subgrade Reaction

4800 - 16000 kN/m3 9600 – 80000 kN/m3 64000 – 128000 kN/m3 32000 – 80000 kN/m3 24000 – 48000 kN/m3 12000 – 24000 kN/m3 24000 – 48000 kN/m3 > 48000 kN/m3

The spring stiffness to be input into SPACE GASS is simply equal to the modulus of subgrade reaction multiplied by the area of the footing that the spring is modelling. For example, if you have a 600mm wide strip footing supported on soil with a modulus of subgrade reaction of 80000 kN/m3 and the soil is modelled as springs spaced 500mm apart, the axial stiffness of each spring would be 80000 x 0.600 x 0.500 = 24000 kN/m. Units for the spring stiffness are shown in the headings of the node restraints datasheet. X, Y and Z rotational stiffnesses Rotational spring stiffness spring stiffnesses for degrees of freedom restrained with "S". Rotational spring stiffnesses must always be greater than zero. Important note about restraining 2D frames It is common practice amongst some engineers to restrain all out-of-plane movements in 2D frames. While this is generally appropriate for static analyses (provided there are no out-ofplane loads), it may not be appropriate for buckling and dynamic frequency analyses. This is because the frame may buckle or vibrate in an out-of-plane direction even though there are no

130

Project Data loads in that direction. Of course, nodes that are braced in the out-of-plane direction should be restrained in that direction, however nodes that can move out-of-plane in the real structure should not be restrained in that direction in the model. Failure to do this could affect the buckling load factors, effective lengths and dynamic natural frequencies and mode shapes, and could result in unsafe designs. For example, if a 2D frame rafter is sub-divided, the intermediate nodes should not be restrained in the out-of-plane direction unless they are braced in that direction in the real structure. Restraining them would prevent any out-of-plane buckling or vibration modes that could occur if the rafter member hadn’t been sub-divided. Another example is a pin support for a 2D XY-plane frame column base which could be modelled with the standard 2D pin base restraint code of FFFFFR, however this would prevent rotations about the global X-axis. In reality, a column pin support would probably allow rotations about both horizontal axes and hence a restraint code of FFFRFR would be more appropriate. Restraining the rotation about the X-axis would affect the out-of-plane buckling and vibration modes of the column and could result in incorrect results. The general rule to follow is that if a node is free to move or rotate in the real structure then it should not be restrained in that direction in the model. Be careful with the general restraint, as it is applied to all nodes that don’t have their own restraint, and for some nodes this may not be appropriate.

If you have applied a general restraint and require some nodes to not have a restraint at all, you can prevent them from getting the general restraint by restraining them with a code of RRRRRR. See also Node restraints text. See also Datasheet Input. See also Node properties. See also View node / member / plate properties.

131


Section property data You can display the section property data for a member by clicking the Member Properties form.

button in the

Section properties must be input for each type of member cross section in the model. Each section property describes the geometric properties of a single cross section relative to the local member axes. Section There are two fields, one for the section property number and the other for the section name. Section property numbers do not have to be sequential or in any particular order. The section property name is used as a description for the section, and as a reference for sections which have been read from a library. Source This indicates the source of the section. There are four different sources: Manual: Library: Shp Bldr: Std Shps:

User defined properties. A shape taken from a library. The source will be the library name (eg. AUST300). Section defined in the Shape Builder. Section defined in Standard Shapes.

See also Standard sections libraries. See also Shape builder.

If you create a section in the shape builder by importing it from the library, and you don’t make any changes to it, the source will be the name of the library the section was taken from. However, you can still edit the shape via the shape builder. You can also edit other library sections in the shape builder, even if the section wasn’t input via the shape builder. Flipped "YES" if the section has been flipped (see also Flipping a section). Angle Type Indicates the angle configuration. Choices are: 132

Single,

Project Data Short-Short, Long-Long, Starred. See also Angle sections. Area of section Cross sectional area of the section. Torsion constant Torsional stiffness of the cross section. Calculating the torsion constant for arbitrary cross sections can be quite complex, particularly if the cross section changes shape (warps) under torsion. For example, a circular tube has a relatively high torsion constant because it doesn’t warp under torsion. However, if a saw cut is made through the tube wall the torsion constant is drastically reduced because the cross section can change shape under very small torsion loads. Thus two shapes with very similar geometric properties can have substantially different torsion constants.

The torsion constant for shapes which cannot warp is equal to the polar moment of inertia. The torsion constants for various common shapes can be calculated using the following formulae.

Solid circle:

Circular tube: Solid square:

Solid rectangle: where A & B are length and breadth (or vice-versa) and A>B I, H, T, L and angle J is equal to the sum of the torsion constants of the sections: composite sections which constitute the total cross-section. Y and Z moments of inertia Principal moments of inertia of the cross section. Y and Z shear areas Principal shear areas of the cross section, where a value of zero represents an "Infinite" shear area. The shear area is the effective cross sectional area which is used in the calculation of shear deformations. In general, the shear area depends upon the shearing stress distribution, which in turn depends upon the shape of the cross section.

133


For rolled steel sections, the major axis shear area is approximately equal to the area of the web(s). For rectangular cross sections, the shear area is equal to A/1.2, where A is the gross area. Values for other shapes are given in standard textbooks on strength of materials.

For most cross sections and materials, the shear deformations are negligible compared to the flexural deformations. Therefore, the shear area can often be specified as infinite. Principal angle Angle (degrees) from principal axes to geometric axes in anti-clockwise direction. For example, the principal angle is positive for single angle sections that have their horizontal leg pointing to the left. Section mark Member mark used in connection detail drawings, marking plans, etc.

Member cross sections are always shown as if you are looking along the member from the node B end to the node A end. See also Section properties text. See also Datasheet Input. See also Member properties. See also Plate properties. See also View rendered model.

134

Project Data

Standard section libraries Standard sections libraries are available for most countries and they include all I sections, H sections, T sections, channels, angles, square tubes, rectangular tubes and circular tubes. See also Standard library.

135


Shape builder You can open the shape builder by clicking the button in the Member Properties form of either the renderer or the traditional graphics window.

The shape builder allows you to modify library shapes, combine library, standard and custom shapes into built-up sections, and create standard and custom shapes. Standard shapes are easily created by clicking on one of the standard shapes buttons and entering the desired dimensions. For a custom shape, you are required to enter three or more coordinates and the shape builder will display the shape and calculate the section properties. Inputting shapes To input a shape, you can: 

Import it from a sections library by clicking the library button



Click the custom shape button perimeter of a shape.



Click the line shape button and then enter a set of coordinates to define a shape formed by a line of a user defined thickness.

136

.

and then enter a set of coordinates to define the

Project Data 

Click one of the standard shape buttons

and then enter its dimensions. Any shape (other than a hollow shape) can be converted to a negative shape (void) by ticking the "Negative shape (hole)" option. This makes it very easy to model voids in your cross section.

Editing and combining shapes You can input up to 10 shapes from any of the above sources and combine them to form your desired cross section. Each shape can be translated, mirrored, rotated or transposed using the shape editing buttons shown below.

Shapes can also be dragged and snapped together via their edge and corner reference points as shown below.

137


When dragging shapes, the behaviour can be controlled using the grid and snap settings along the bottom of the shape builder as shown below.

Shapes can be copied by dragging while holding down the Ctrl key.

138

Project Data

Multiple shapes can be selected by clicking them while holding down the Shift key. You can then use the alignment buttons at the top of the shape builder to align the selected shapes along the top, bottom, center, left or right. Alternatively, you can stack shapes vertically or horizontally using the stack alignment buttons

.

139


Dimensions Dimensions can be added to shapes by clicking the dimensions button

140

.

Project Data

Design properties SPACE GASS can now do a steel member design or check using sections that haven't been imported from a library, however you must specify their steel design properties. You can do this via the shape builder "Design Properties" button. Generally speaking, you would only use the "Design Properties" button when are you don't want to save the section to a library because the saving to library process also includes inputting the steel design properties.

Saving sections You can save your section to a custom library for later recall into any other jobs by clicking the "Save to Library" button

and then filling out the form that appears below.

141


If a custom section library doesn’t yet exist or if you wish to create a new custom library, click the button at the right of the "Library" field and then fill out the custom library’s details. Similarly, if the library doesn’t yet contain any groups or if you wish to create a new group within a custom library, click the then fill out the group’s details.

button at the right of the "Group" field and

The SPACE GASS section libraries can now contain built-up sections made from whatever shapes you can build in the shape builder, including voids. Built-up or non-standard sections cannot be used in the design/check modules, however they can be recalled into any other jobs and used in a static, dynamic or buckling analysis.

The shape builder always shows the cross section as if you are looking along the member from node A towards node B. This is the reverse of how it was in SPACE GASS 10 and earlier versions.

The section properties displayed in the panel on the right side of the shape builder apply to the whole cross section (ie. the sum of the composite shapes in the display window). See also Member properties. See also View rendered model.

142

Project Data

Flipping a section If the properties of a section have been read from a library, SPACE GASS then asks if the section has been flipped. This simply causes the section to have its major and minor section properties transposed and allows the section to be used in the frame with its major axis parallel to the local y-axis instead of the z-axis. In most cases, the major axis of a member is parallel to its local z-axis (see also Coordinate systems). When a section is flipped, the orientation of the local y and z axes are not affected. This information is not required for sections with equal major and minor axis section properties.

Flipped section orientation

You can see from the diagram above that when the section is flipped, the y and z axes remain unchanged. This method of flipping a section is different to applying a 90 direction angle to a member. A direction angle rotates the local axes together with the section, while the above method simply transposes the section properties. Note that the transposed properties apply to every member which references the flipped section property number, while a direction angle rotation affects only the member(s) to which it is applied.

143


Column and beam Tee sections Column Tees have the major axis parallel to the web and are therefore assumed to be lying on their side with their flange vertical (assuming a zero direction angle and no flipping). They are orientated at right angles to normal beam Tees which have the major axis parallel to the flange.

Tee section orientation

144

Project Data

Angle sections For angle sections, you can specify single or double angle sections. Choices are:

Single angle, Double angle with short legs connected, Double angle with long legs connected, Double angle starred (equal angles only).

Angle section orientation

The diagrams above show the orientation of a single angle section and the available double angle sections. Note that the z-axis is the major axis in all cases.

For double equal angles, the long leg is assumed to be the vertical leg in the diagrams above. Note that in SPACE GASS 10 and earlier, double equal angle sections with long legs connected were adjusted internally and treated as though their short legs were connected. This adjustment was removed in SPACE GASS 11 and later versions.

145


Material property data You can display the material property data for a member by clicking the button in the Member Properties form. The material property data for a plate is always shown in the Plate Properties form.

Material properties must be input for each type of member or plate material in the model. Each material property describes the properties of a single isotropic material. Material There are two fields, one for the material property number and the other for the material name. Material property numbers do not have to be sequential or in any particular order. The material name is used as a description for the material, and as a reference for materials which have been read from a library. E Value of Young’s Modulus for the material. Poisson’s Value of Poisson’s Ratio for the material. Mass Dens Mass density, required only for self weight calculations. Temp Coeff The coefficient of thermal expansion, required only for thermal loads. You must ensure that this is appropriate for the temperature units you have selected (see also Units).

146

Project Data F’c Characteristic concrete strength, required only for concrete materials. Is used only in the SPACE GASS concrete design modules. See also Material properties text. See also Datasheet Input. See also Member properties. See also Plate properties.

147


Master-slave constraint data You can display the master-slave constraints data for a node by clicking the Node Properties form.

button in the

Master-slave constraints allow you to connect nodes together with imaginary links so that they translate and/or rotate together. The degree of constraint can be varied so that any or all of the six degrees of freedom of a node can be linked to another node. For example, it is possible to connect two nodes together with a 3D rigid link, a 2D rigid link, a 2D translational link, a 2D rotational link, a 1D translational link, a 1D rotational link or any other combination of the six degrees of freedom.

A node which is linked to another node is termed a "slave node" and the node to which it is linked is termed its "master node". A master node can have many slave nodes, however a slave node can have only one master node. A typical frame can have many slave nodes and many master nodes. A master node cannot be the slave of another master node. A slave node constrained DOF cannot be a support (restraint). A constraint link between a slave node and its master node not only affects the movements of the slave but also the master. Node Slave node to be constrained. Master node The node to which the slave node is to be constrained. You can select a master node by clicking the "Select" button and then choosing a node. Constraint code Master-slave constraints are controlled by a six character constraint code which specifies the exact constraint relationship between a slave node and its master. The six characters of the constraint code correspond to translational constraint along X, Y and Z and rotational constraint about X, Y and Z respectively. "F" represents fixed (constrained) and "R" represents released (unconstrained). In order to illustrate how the constraint code works, we will consider some typical examples of constraints in the global XY plane. Please note that the following examples apply equally to the XZ and YZ planes also.

148

Project Data When considering the XY plane, the only significant characters in the constraint code are the first, second and sixth. These correspond to translation along X and Y, and rotation about Z. When considering the XZ plane, only the first, third and fifth characters apply, and when considering the YZ plane, only the second, third and fourth characters apply. If a slave node has a constraint code of "RFxxxR" (where xxx could be any combination of F’s and R’s) then its Y-axis translation will be the same as its master node. Note that the Xaxis translation and the Z-axis rotation of the slave node will be completely independent and in no way affected by its master node. This can be represented by the simple constraint equation Dys = Dym, where Dys is the slave Y-axis translation and Dym is the master Y-axis translation. Similarly, if a slave node has a constraint code of "RRxxxF" then its Z-axis rotation will be the same as its master node and the X-axis and Y-axis translations will be independent. The constraint equation in this case is Rzs = Rzm, where Rzs is the slave Z-axis rotation and Rzm is the master Z-axis rotation. A slightly different situation occurs if both a translational degree of freedom and a rotational degree of freedom are constrained. An example of this is a constraint code of "FFxxxF". In this case, the constraint code effectively places a 2D imaginary rigid member between the slave node and its master so that the translations of the slave node are a function of both the translations and the rotation of the master node. The constraint equations in this case are Dxs = Dxm-Ly*Rzm Dys = Dym+Lx*Rzm Rzs = Rzm where Lx and Ly are the horizontal and vertical components of the distance between the slave and master nodes.

Constraint movements

The following list shows some common constraint codes. 149


FRRRRR RFRRRR RRFRRR RRRFRR RRRRFR RRRRRF FFFRRR

RRRFFF

FFRRRF

FRFRFR

RFFFRR

FFFFFF

X translation (Dxs=Dxm) constrained Y translation (Dys=Dym) constrained Z translation (Dzs=Dzm) constrained X rotation constrained (Rxs=Rxm) Y rotation constrained (Rys=Rym) Z rotation constrained (Rzs=Rzm) X, Y and Z (Dxs=Dxm) translations constrained (Dys=Dym) (Dzs=Dzm) X, Y and Z rotations (Rxs=Rxm) constrained (Rys=Rym) (Rzs=Rzm) Rigid link in XY (Dxs=Dxm-Ly*Rzm) plane (Dys=Dym+Lx*Rzm) (Rzs=Rzm) Rigid link in XZ plane (Dzs=Dzm-Lx*Rym) (Dxs=Dxm+Lz*Rym) (Rys=Rym) Rigid link in YZ plane (Dys=Dym-Lz*Rxm) (Dzs=Dzm+Ly*Rxm) (Rxs=Rxm) Rigid link in all (Dxs=Dxm-Ly*Rzm+Lz*Rym) planes (Dys=Dym+Lx*Rzm-Lz*Rxm) (Dzs=Dzm-Lx*Rym+Ly*Rxm) (Rxs=Rxm) (Rys=Rym) (Rzs=Rzm)

Any further combinations of the six character constraint code can also be specified. The following diagrams show the effect that each of the XY plane constraints have. The effects shown apply equally to the XZ and YZ planes also. Note that constraint codes for any of the three planes can be combined together as can be seen in the examples above.

150

Project Data

Typical constraint links

Master-slave constraints can be used to great advantage in many structures. They are particularly useful for modelling floor slabs in three dimensional frames. A typical floor slab may displace and rotate in plan as a unit but its plan dimensions do not change due to its large in-plane rigidity. This could be modelled in SPACE GASS by using one of the perimeter nodes in a typical floor slab as the master node for that floor and specifying all of the other perimeter nodes in that floor to be slaves of the master node in the in-plane (XZ plane) directions using a constraint code of "FRFRFR". Thus all nodes in the floor would move as a unit in the in-plane (horizontal plane in this case) directions. They would still, however be free to move independently in the out-of-plane (vertical) direction.

151


Rigid diaphragm modelled with constraints

Another example is the case of wind bracing or a scissor lift where two continuous members cross each other and are connected to each other with a bolt or pin. The pin transfers shear from one member to the other but not moment so that the members are free to rotate about the pin independently.

Scissor lift modelled with constraints

This situation is very difficult to model in a frame analysis program unless a constraint facility is available. Using a master-slave constraint, it is a simple matter to locate two nodes on the same point where the two members cross. One of the members would be connected to

152

Project Data the first node and the other member would be connected to the second node. Assuming that the frame was in the XY plane, a constraint code of "FFRRRR" could then be used to force the two nodes to translate together but rotate independently. A third example of a common master-slave constraints application is in the modelling of a shear wall. A column of nodes consisting of one master and the rest slaves could be used to form the wall itself. Any other nodes connected directly to the wall could also be slaves of the master. Assuming that the wall was in the XY plane, a constraint code of "FFRRRF" could be used. Another situation which is difficult to model without using a master-slave constraint occurs when two members of different depths are connected together end-to-end such that their centrelines do not line up. In such cases a node could be placed at the end of each member and then a master-slave constraint could be used to join the two nodes together with a rigid link. In some situations, short stiff members could be used as an alternative to constraint links, however they would be susceptible to ill-conditioning problems, particularly if they were very stiff in comparison to other members in the structure.

Master-slave constraints do not suffer from ill-conditioning problems, regardless of how short the links are. See also Master-slave constraints text. See also Datasheet Input. See also Node properties. See also View node / member / plate properties.

153


Member offset data You can display the offsets data for a member by clicking the Properties form.

Choices are:

button in the Member

Local, Global.

It is possible to specify a rigid member segment that doesn’t deform under bending at each end of a member. These rigid segments have infinite stiffness for bending, shear and axial deformations. Member offsets are very useful for modelling the very stiff area at the interconnection of members (especially stiff members such as large steel members or concrete members).

Member offsets

For example, the rectangular reinforced concrete frame shown above on the left could be modelled quite accurately with SPACE GASS using a model similar to the one shown on the right. Each member in the model has short member offsets at each end where intersecting members overlap. Member offsets are also very useful in situations where the centrelines of connected members do not intersect at a node. For example, the diagonal brace members of a plane truss may intersect below the top chord centreline. Member offsets could be used to allow for this. Member offsets could also be used to model the centreline mismatch when members of different depths are connected end-to-end with "top-of-steel" alignment.

154

Project Data

The ends of a member with "local" offsets are offset relative to an axis connecting the end nodes of the member rather than being relative to the axis of the member in its final position. ! IMPORTANT NOTE ! Be careful when sub-dividing members that have local offsets because the direction of the axis that the offsets are relative to will change when any intermediate nodes are added. See also Member offset text. See also Datasheet Input. See also Member properties. See also View node / member / plate properties.

155


Node load data

Concentrated forces and moments may be applied to any node along or about the global X, Y and Z axis directions. If a load is applied to a restrained degree of freedom then that load is simply added to the final reaction. Node loads may be applied in any number of load cases and may be combined with other load types within the same load case. Case Load case to contain node loads. Node Node to be loaded. X, Y and Z forces Node forces (global axes). X, Y and Z moments Node moments (global axes). See also Node loads text. See also Datasheet Input. See also Node loads. See also View diagrams.

156

Project Data

Prescribed node displacement data

Prescribed node displacements allow you to specify known displacements and/or rotations to nodes. They can be very useful for situations where a frame deflects by a fixed and known amount such as settlement of a support for example.

Prescribed displacements may only be applied to restrained (fixed or deleted) degrees of freedom, otherwise they are ignored. Prescribed node displacements may be applied in any number of load cases and may be combined with other load types within the same load case. It is important to note that like all other load types, prescribed node displacements do not have any effect on load cases other than the ones in which they are input. Case Load case to contain prescribed displacements. Node Node to be displaced. X, Y and Z translations Node translations (global axes). X, Y and Z rotations Node rotations (global axes). See also Prescribed node displacements text. See also Datasheet Input. See also Prescribed node displacements. See also View diagrams.

157


Member concentrated load data

Concentrated forces and moments may be applied to members in either the global or the local axes systems. Such loads can act along or about any of the three axis directions and can be located at any point along the member. Member concentrated loads may be applied in any number of load cases and may be combined with other load types within the same load case. Case Load case to contain concentrated member loads. Member Member to be loaded. Sub load This allows you to reference multiple concentrated loads on a member in the same load case. Each load is given a sub load number (different to a load case number). For example five concentrated loads applied to a member within the same load case would have sub load numbers of 1,2,3,4 and 5 respectively. Unless there are multiple loads applied to a single member within the same load case, the sub load number should be 1. Axes Axes system in which loads are referenced. Choices are:

Local, Global.

Units Units system in which load positions are referenced. Choices are:

Actual, Percentage.

Position The load position is defined as the distance from node A to the load. Depending on the "Units system" selected, this distance may be expressed as an absolute length or as a percentage of the member length. Thus, a member 600mm long with a load at midspan could have the load position specified as 300mm or as 50%. X, Y and Z forces Member concentrated forces.

158

Project Data X, Y and Z moments Member concentrated moments. See also Member concentrated loads text. See also Datasheet Input. See also Member concentrated loads. See also View diagrams.

159


Member distributed force data

Member distributed forces can be input in the local or global axes systems and can act along any of the three axis directions. Distributed forces may start and finish at any point along the member length and may vary in intensity from start to finish. Thus, it is possible to apply uniform, trapezoidal, or triangular distributed loads. Member distributed forces may be applied in any load case and may be combined with other load types within the same load case. ! IMPORTANT NOTE ! For "Local" or "Global Inclined" loads, the total load is equal to the load per unit length multiplied by the actual distance between the load start and finish positions. For "Global Projected" loads, the total load is equal to the load per unit length multiplied by the projected distance between the load start and finish positions. ! IMPORTANT NOTE ! For cable members, distributed forces must be uniform and extend over the entire length of the cable. For "Global Inclined" UDLs applied to cable members, the total load is equal to the load per unit length multiplied by the unstrained cable length (which may not be equal to the distance between the cable’s end nodes). For "Global Projected" UDLs applied to cable members, the total load is equal to the load per unit length multiplied by the projected distance between the cable’s end nodes. Case Load case to contain distributed member forces. Member Member to be loaded. Sub load This allows you to reference multiple distributed loads on a member in the same load case. Each load is given a sub load number (different to a load case number). For example two distributed loads applied to a member within the same load case would have sub load numbers of 1 and 2 respectively. Unless there are multiple loads applied to a single member within the same load case, the sub load number should be 1. Axes Axes system in which loads are referenced. There are two global axes systems which may be used. When the axes are designated as "Global projected" the load acts over the projected

160

Project Data length of the member, while a "Global inclined" load acts over the actual length of the member. Choices are:

Local, Global projected, Global inclined.

Units Units system in which load positions are referenced. Choices are:

Actual, Percentage.

Start and finish positions The load start and finish positions are taken relative to node A. Depending on the "Units system" selected, this distance may be expressed as an absolute length or percentage of the member length. Thus, a member 600mm long with a load that extends from the 150mm mark to the end could have the load start position specified as 150mm or as 25%, and the load finish position specified as 600mm or as 100%. The finish position must always be greater than start. X, Y and Z start and finish forces Start and finish member distributed forces. See also Member distributed forces text. See also Datasheet Input. See also Member distributed forces. See also View diagrams. See also Cable members.

161


Member distributed torsion data

Member distributed torsion loads are similar to member distributed forces except they may only be applied about the local x-axis. The load intensity may be varied between the start and finish positions. Member distributed torsions may be applied in any load case and may be combined with other load types within the same load case. Case Load case to contain distributed member torsions. Member Member to be loaded. Sub load This allows you to reference multiple distributed torsions on a member in the same load case. Each load is given a sub load number (different to a load case number). For example two distributed torsions applied to a member within the same load case would have sub load numbers of 1 and 2 respectively. Unless there are multiple loads applied to a single member within the same load case, the sub load number should be 1. Units Units system in which load positions are referenced. Choices are:

Actual, Percentage.

Start and finish positions The load start and finish positions are taken relative to node A. Depending on the "Units system" selected, this distance may be expressed as an absolute length or percentage of the member length. Thus, a member 600mm long with a load that extends from the 150mm mark to the end could have the load start position specified as 150mm or as 25%, and the load finish position specified as 600mm or as 100%. The finish position must always be greater than start. Start and finish torsion load Start and finish member distributed torsion load.

162

Project Data See also Member distributed torsions text. See also Datasheet Input. See also Member distributed torsions. See also View diagrams.

163


Thermal load data

A thermal load can be applied to a member by specifying a temperature change, while a thermal load can be applied to a plate in the form of a temperature change or a thermal gradient across its thickness. Thermal loads act over the entire length of the members or area of the plates to which they are applied. Thermal loads may be applied in any load case and may be combined with other load types within the same load case. Case Load case to contain thermal loads. Element Member or plate to be loaded. Thermal load Uniform temperature change. Thermal gradient (plates only) Thermal gradient across plate thickness. A positive thermal gradient causes the top (positive z-axis) face of the plate to expand and the bottom face to contract. Unlike other load types, you can apply thermal loads to nonexistent members or plates without causing an analysis error. Such loads are simply ignored during the analysis phase. For example, in order to apply a uniform 10 temperature change to an entire structure with a highest member number of less than 100, you could simply generate 10 thermal loads on members 1-100 without concerning yourself about possible gaps in the member numbering sequence. See also Thermal loads text. See also Datasheet Input. See also Thermal loads. See also View diagrams.

164

Project Data

Member prestress data

A prestress can be applied to a member by specifying a tensile or compressive force. Prestress loads act over the entire length of the members on which they are applied. It is possible to model prestress loads with equivalent thermal loads and vice-versa, however this is generally unnecessary because they can both be applied directly in SPACE GASS. Prestress loads may be applied in any load case and may be combined with other load types within the same load case.

Note that the prestress load you apply to a member is not likely to be the final axial force in the member at the end of the analysis (unless its ends are fixed in position or don't move). This is because the axial force changes as the member stretches or compresses as its end nodes move. If you wish to achieve a particular axial force at the end of the analysis then a trial and error process is required. This involves setting an initial prestress force, performing the analysis, checking the final axial force, adjusting the prestress and repeating the process until the desired axial force is achieved. This is a common requirement in posttensioned concrete applications where the tendons are jacked to a known tension. Case Load case to contain prestress loads. Member Member to be loaded. Prestress force The prestress force is positive for compression or negative for tension. In some instances, you may wish to apply a prestress load to a cable member instead of specifying a non-zero unstrained cable length. The prestress load P that is equivalent to an unstrained cable length L is given by the equation:

165


where

D = chord length, A = cross sectional area, E = Young’s modulus of elasticity.

See also Member prestress loads text. See also Datasheet Input. See also Member prestress loads. See also Cable members. See also View diagrams.

166

Project Data

Plate pressure data

Pressure loads may be applied to plates in either the global or the local axes systems. Such loads can act along or about any of the three axis directions and always extend over the entire plate surface. Plate pressure loads may be applied in any number of load cases and may be combined with other load types within the same load case. Case Load case to contain plate pressure loads. Plate Plate to be loaded. Axes Axes system in which loads are referenced. Choices are:

Local, Global.

X, Y and Z pressure Plate pressure loads. Plate pressure loads can be input graphically as explained in Plate pressure loads or, for variable pressure loads such as hydrostatic or wind loads, the Varying plate pressure loads tool can be used. See also Plate pressure loads text. See also Datasheet Input. See also Plate pressure loads. See also Varying plate pressure loads. See also View diagrams.

167


Self weight data

Self weight loads are considered as forces and moments in a static analysis and as masses in a dynamic analysis. Self weight can be automatically generated by the program if an acceleration (such as gravity) is specified. Acceleration may be specified along any of the three global axis directions. Note that self weight will only be considered if non-zero mass densities are specified in the material property data. When self weight loads are used as masses in a dynamic analysis, the direction and magnitude of the X, Y and Z accelerations are ignored. The process simply involves calculating the mass of each member and then applying half of it as translational lumped masses to each of the member end nodes in each of the unrestrained X, Y and Z global axis directions. Self weight may be applied in any load case and may be combined with other load types within the same load case. Case Load case to contain self weight. X, Y and Z acceleration Acceleration applied to the entire structure. See Units for the appropriate acceleration units that apply. See also Self weight text. See also Datasheet Input. See also Self weight. See also Cable members.

168

Project Data

Combination load case data

All loads applied to a structure are always input via primary load cases. Further load cases can be created by combining the various primary load cases into combination load cases.

Combination load cases can be combined into further combination load cases. Combination case Load case to be formed. Cannot be equal to a primary load case. Case Load case to be factored and combined into the combination. This can be a primary load case or a combination load case. Multiplying factor The multiplying factor applied to the primary load case when it is combined. Consider for example a structure that is to be analysed for the following combination load cases 10, 11 and 12. Load case 1: Load case 2: Load case 3: Load case 4: Load case 5: Load case 20: Load case 21: Load case 22: where

Self weight (SW) Floor load (LL1) Roof traffic (LL2) Cladding (CL) Wind load (WL) 1.25*DL + 1.50*LL 0.80*DL + 1.50*LL 0.80*DL + 1.00*WL, DL = SW + CL LL = LL1 + LL2

The desired combination load cases could then be made up as follows. Load case 10 (DL):

1.00*Load case 1 + 1.00*Load case 4

169

SPACE GASS 12 User Manual Load case 11 (LL): Load case 20: Load case 21: Load case 22:

1.00*Load case 2 + 1.00*Load case 3 1.25*Load case 10 + 1.50*Load case 11 0.80*Load case 10 + 1.50*Load case 11 0.80*Load case 10 + 1.00*Load case 5

Note that for a linear analysis, it is not necessary to analyse the combination load cases. They can be calculated by simple linear superposition of the primary load case results during the output phase. For a non-linear (2nd order) analysis however, the simple linear superposition rules don’t apply and combination load cases have to be fully analysed and treated in the same way as primary load cases. For this reason, SPACE GASS allows you to decide whether or not to analyse the combination load cases and treat them the same as primary load cases or to not analyse them and have them calculated by simple linear superposition during the output phase. You can specify the load cases that you want analysed by listing them at the start of the analysis phase. For example, if you have primary load cases 1,2,3 and 4, and combination load cases 10,11 and 12, you could analyse just the primaries by entering 1-4 for the load cases list.

If you are doing a dynamic spectral response analysis, you should create a reverse combination load case for each spectral load case. You may also have to create further combinations to combine the spectral load cases with different direction vectors. For more information refer to Spectral load data.

SPACE GASS will not allow a combination load case to be a simple linear combination of analysed primary load cases if any of the primaries have been analysed nonlinearly or if the frame contains tension-only or compression-only members. In this case the combination load case must be analysed. You can modify the combination load case data and obtain new results without re-analysing the structure, however this only applies to linear superposition combinations. Results for analysed combinations are deleted if the combination load case data is changed. See also Combination load cases text. See also Datasheet Input. See also Combination load cases.

170

Project Data

Load case title data

Load case titles serve the purpose of creating clearer, more understandable output. Primary or combination load cases may be given titles. Case Load case to have title defined. Title A description of the load case. Notes Notes that allow you to describe the load case in more detail. See also Load case titles text. See also Datasheet Input.

171


Lumped mass data

Lumped masses are considered in a dynamic analysis and are ignored in a static analysis. Translational or rotational masses can be applied to any node along or about the global X, Y and Z axis directions. If a mass is applied to a restrained degree of freedom then that mass is simply ignored during the dynamic frequency analysis. Masses may be applied in any load cases and may be combined with static loads within the same load case, although it is often a good idea to put masses in load cases of their own (ie. not in with static loads) so that they can be isolated in graphics displays or output reports. Self mass can be added to the lumped masses by either by adding self-weight to a load case that contains lumped masses or by combining lumped mass and self-weight load cases into a combination load case. Case Load case to contain lumped masses. Node Node to have masses applied. X, Y and Z translational masses Translational masses (global axes). X, Y and Z rotational masses Rotational masses (global axes). The application of lumped masses A mass that affects the natural frequencies of a structure must be applied in each of the unrestrained directions of the node to which it is attached. For example, a 0.5 tonne machine which is attached to a point on a building rafter has an inertia in each of the X, Y and Z directions and effects the natural frequencies of the building in all three directions. It must therefore be applied as 0.5 tonne X, Y and Z translational masses. ! IMPORTANT NOTE ! Lumped masses are not the same as loads and therefore cannot be calculated by simply converting loads to mass units. Masses represent the structure and/or attachments to the structure which move and rotate with it and which effect its natural frequencies. Some types of loads would have to be input as lumped masses while others would not. For

172

Project Data example, dead loads and 30-100% of live loads would normally affect the natural frequencies of a structure, however wind loads would not. The inertia of the structure could be modelled in one of the following two ways: Translational masses Consider a rigid floor slab. You could model the distribution of mass by placing a small translational mass at each node in the slab (the sum of all node masses equalling the total mass of the slab). Translational and rotational masses You could also model the rigid floor slab by lumping all of the translational mass and a rotational mass at the centroid of the slab. In the first approach, the rotational inertia would be provided by the action of each of the small translational masses being a distance away from the centroid of the slab. In the second approach, the rotational inertia would be provided directly by the rotational mass at the centroid of the slab. It is usually more convenient and just as accurate to use the second approach. The rotational mass for a point at the centroid of a rectangle is

where m is the mass of the rectangle, and a and b are the dimensions of the rectangle. The concept of rotational mass, together with formulae for calculating rotational masses at various locations on rectangles and other shapes, is given in Clough and Penzien (10). Self mass It is not necessary to manually input lumped masses for the self mass of the structure because self mass can automatically be considered by simply adding self-weight to one or more load cases. However, automatic self mass generation does not calculate rotational masses because of the large number of extra masses that would be generated for a fairly insignificant improvement in results accuracy. If required, rotational self mass must be manually applied as rotational lumped masses. In order to adequately define the distribution of mass along members for which local vibrations are important, it is sometimes necessary to add intermediate nodes (with masses applied) to such members. See also Lumped masses text. See also Self-weight. See also Datasheet Input. See also Lumped masses. See also View diagrams. See also Dynamic frequency analysis. See also Running a dynamic frequency analysis.

173


Spectral load data

In order to perform a response spectrum analysis, you must first create one or more spectral load cases. A spectral load case contains the number of a mass load case, a direction vector and a list of mode shapes, each with its associated spectral curve and damping factor. Spectral load cases can be combined and multiple spectral load cases can be analysed simultaneously.

The mode shapes must have been calculated from a dynamic frequency analysis before the response spectrum analysis can proceed. Case The spectral load case being created (see also "load cases" below). Mode A mode shape being included in the spectral load case. Multiple mode shapes can be included in a single spectral load case by simply inputting multiple entries (lines) with the same spectral load case number. A particular mode shape can appear only once in each spectral load case. In the spectral analysis, it is important to consider a sufficient number of mode shapes. SPACE GASS provides a very efficient means of measuring the contribution of each mode shape in the overall dynamic response. This is known as the mass participation factor. For example, for an earthquake acting in the X direction, the total X-axis mass participation factor should be greater than 90% (eg. AS1170.4 clause 7.4.2). If it is less than 90% then a few more mode shapes should be included in the analysis. A small mass participation factor will indicate inaccurate results. For more information, refer to "Dynamic spectral response analysis results". It is important that you include the fundamental mode (ie. the mode with the longest period in the direction of the earthquake), together with all other modes that have significant mass participation. If you're not sure which modes to include then you should list them all. It will improve the accuracy of the analysis and won't significantly affect the analysis time. Spectral curve The name of the spectral curve to be used with the specified mode shape. Normally all mode shapes in a spectral load case use the same spectral curve, however you can nominate different spectral curves for each mode if desired.

174

Project Data Damping The damping factor associated with the nominated spectral curve. This value is built into each spectral curve when it was derived and cannot be changed. It is included in the datasheet for display purposes only. Mass case The mass load case for which the specified mode shapes have been (or will be) calculated from a dynamic frequency analysis. Direction vector Defines the direction of the ground vibration. For example, an earthquake acting in the X direction would have a direction vector of Dx=1.0, Dy=0.0 and Dz=0.0. Note that for the NZS and IS codes, if auto-scaling of the base shear is activated, the direction vector should be parallel to one of the horizontal global axes. For these codes, to model a direction vector that is at an angle to the horizontal global axes, you should create a separate spectral load case for each of the horizontal global axis directions and then combine them into a combination load case using multiplying factors that are proportional to the projected lengths of the desired direction vector. Load cases For building structures, it is common to input two spectral load cases per mass load case, one for each of the orthogonal horizontal directions. Furthermore, if the loading code requires you to consider a combination of the two orthogonal directions (ie. AS1170.4-2007 5.4.2.1, NZS1170.5-2004 5.3.1 or IS1893.1 6.3.2.2) then further load cases may also be required. Finally, because the dynamic vibrations oscillate from one side to the other, it is also necessary to consider the reverse of all of the above load cases. For example, consider two basic spectral load cases defined for a particular mass load case as follows: Load case 21 = Direction vector 1,0,0 (ie. earthquake in X-axis direction) Load case 22 = Direction vector 0,0,1 (ie. earthquake in Z-axis direction) If the loading code requires further combinations of the above load cases in the form of 100% of the actions in one direction plus 30% of the actions in the perpendicular direction then further load cases are required. These are most conveniently input as combination load cases as follows: Load case 23 = 1.0 x case 21 + 0.3 x case 22 Load case 24 = 1.0 x case 21 - 0.3 x case 22 Load case 25 = 1.0 x case 22 + 0.3 x case 21 Load case 26 = 1.0 x case 22 - 0.3 x case 21 Finally, the reverse of the all the above load cases must be defined as further combination load cases as follows: Load case 31 = -1.0 x Load case 21 Load case 32 = -1.0 x Load case 22 Load case 33 = -1.0 x Load case 23 Load case 34 = -1.0 x Load case 24 Load case 35 = -1.0 x Load case 25 Load case 36 = -1.0 x Load case 26

175

SPACE GASS 12 User Manual Thus, each pair of basic spectral load cases can spawn up to a further ten combination load cases. The structure should be designed to resist the envelope of all load cases.

176

Project Data

Spectral curve editor You can open the spectral curve editor by opening the "Spectral Load Data" datasheet from the Loads menu and then clicking the

button.

You can select the desired spectral curve from the tree in the left-hand window and observe its data values in the right-hand window. You can also click the spectral curve editor button (next to the Ok button) to load and display the spectral curve editor as shown below.

The spectral curve editor can be used to input or edit curves in the spectral curve library. Note, however, that the standard curves supplied with SPACE GASS can’t be changed. The editor allows you to create a spectral curve that will result in the most accurate analysis possible. Operation of the spectral curve editor is self-explanatory and simply involves selecting a curve name and then inputting or modifying its properties. Each curve contains a set of period versus acceleration pairs, a description and a damping factor. You can go to a specific point in a curve by clicking near it in the graphics window or by scrolling to and selecting it in the list box. The currently selected point in the list box is highlighted by a small circle in the graphics window. You can add (or delete) points by clicking the buttons below the list box. See also Standard Libraries for general information about the operation of the library editor.

177


Importing a spectral curve You can import a spectral curve directly into the spectral curve editor by right-clicking the spectral library that you want to import the curve into and selecting "From Text File" or "From Excel". Note that you can't import into a standard library and so you have to create a custom spectral library first. You can do this by clicking the "Add Library" button near the bottom of the form. In order to successfully import a spectral curve into the spectral curve editor you must ensure that you use the correct format in the text or Excel file. You can create a text or Excel file to use as a pattern for creating your own file by simply exporting one of the standard spectral curves. Right-click on one of the existing curves and then choose the "Export..." option to do this. The correct format is as follows: Line 1 Line 2 Line 3 Line 4 …etc. …etc. Line n Line n+1

Description:Damping factor period,acceleration period,acceleration period,acceleration

{for point 1} {for point 2} {for point 3}

period,acceleration period,acceleration

{for point n-1} {for point n}

For example: AS1170.4 S=1.0:5% 0.00,2.5 0.01,2.5 0.02,2.5 … … 2.99,0.602276 3.00,0.600937 See also Spectral loads text. See also Datasheet Input. See also Dynamic spectral response analysis. See also Running a dynamic spectral response analysis.

178

Project Data

Area load data

179


The area loads tool generates member distributed forces based on pressure loads applied to areas defined by members that you have selected. For more information see Area loads and Member distributed forces.

180

Project Data

Sea load data

This tool lets you generate wave and ocean current loads on submerged structures in marine and offshore environments where these effects impose significant loading on the affected structure. For more detailed information refer to "Sea Loads".

181


Moving load data The moving loads tool generates loads on nodes, members and plates subjected to moving or stationary loads such as vehicles, cranes or conveyors.

Features include:                

Loads can be moving or stationary. Load sources can be wheeled vehicles such as trucks or cranes, or distributed loads such as pressure patches or line loads. Multiple scenarios allow you to model any combinations of moving and stationary loads. Moving loads can be combined with other static loads. A lane generation tool is included for roads and bridges. Travel paths and lanes can have multiple segments, including curved segments. Loads can be generated on nodes, members and plates. Libraries of standard vehicles are included for various countries. Loads can share common travel paths or lanes. A speed, delay and start position can be specified for each load. Load factors, lane factors and dynamic load allowances can be specified. A loading area can be defined so that loads which move outside of it become inactive. A vertical proximity setting enables independent generation of loads on multi-level roadways. Moving load data can be exported to MS-Excel, MS-Word or a text file. Moving load data can be imported from MS-Excel or a text file. An animated display allows you to view your loads moving along the structure.

For full details refer to "Moving loads".

182

Project Data

183

Text File Input Text file input Select "Import from text" or "Export to text" from the File menu Inputting data into SPACE GASS via a text file is sometimes faster than using datasheet input, however it is not as user friendly and is not recommended for first time users of SPACE GASS. You can use Windows Notepad to edit or create text files. The text editor linked to SPACE GASS can be started by choosing "Text editor" from the File menu. SPACE GASS text file names have the form .TXT, where is any name. The text file should be located in the text data folder as created during the installation procedure. If a large proportion of the data for a job has to be modified and you do not wish to use the normal editing facilities, the data can be put into a text file which can then be edited using a word processor or text editor, and then imported back into SPACE GASS.

185


Text file format Each data group in a SPACE GASS text file must be preceded by a title line. The title line describes the type of data in the lines to follow. For example, the node data would be preceded by "NODES". When reading text files the program uses only the first six characters of each title line, therefore when creating text files you can abbreviate title lines to their first six characters. It is possible to repeat data throughout the data file. Single items or whole groups can be repeated. In such cases the last entry overrides any previous entries. For example, if node coordinates were entered at the top of the file and then updated at the end, the last group would override the first. This practice, however is not recommended. Groups of data do not have to be input in any particular order. The program recognises the data types by their title lines rather than their order of appearance.       

Items within a line must be separated by commas. Lines can be continued on the next line if they end with the "&" character. The maximum length of a single line is 1024 characters. The maximum length of a set of continued lines is 2048 characters. Comment lines must begin with the "#" character. Blank lines are permitted anywhere in the file. Non-numeric items that contain commas must be enclosed in "quotes".

Real numbers in SPACE GASS text files no longer need to contain a decimal point. Furthermore, all numbers in SPACE GASS text files can now be up to 15 digits long (they were previously limited to 10 digits).

186

Text File Input

Initiator Line 1: Line 2:

SPACE GASS Text File - Version 1228 UNITS LENGTH:Len, SECTION:SecProp, STRENGTH:MatStr, DENSITY:Dens, TEMP:Temp, FORCE:Force, MOMENT:Mom, MASS:Mass, ACC:Acc, TRANS:Trans, STRESS:Stress

Len SecProp MatStr

Length units (ft, in, m, cm or mm) Section property units (ft, in, m, cm or mm) Material strength units (Ksf, Psf, Ksi, Psi, MPa, kPa, Pa, kg/m^2, kg/cm^2, kg/mm^2) Mass density units (K/ft^3, K/in^3, lb/ft^3, lb/in^3, T/m^3, T/cm^3, T/mm^3, kg/m^3, kg/cm^3, kg/mm^3) Temperature units (Fahrenheit, Celsius) Force units (K, lb, kN, N, kg) Moment units (Kft, Kin, lbft, lbin, kNm, kNcm, kNmm, Nm, Ncm, Nmm, kgm, kgcm, kgmm) Mass units (K, lb, T, kg) Acceleration units (g's, ft/sec^2, in/sec^2, m/sec^2, cm/sec^2, mm/sec^2, kN/kg) Translation units (ft, in, m, cm, mm) Stress units (Ksf, Psf, Ksi, Psi, MPa, kPa, Pa, kg/m^2, kg/cm^2, kg/mm^2)

Dens

Temp Force Mom

Mass Acc

Trans Stress

(Chars) (Chars) (Chars)

(Chars)

(Chars) (Chars) (Chars)

(Chars) (Chars)

(Chars) (Chars)

See also Units.

187


Headings text Line 1: Line 2: Line 3: Line 4: Line 5:

HEADINGS Project Job Designer Notes

Project Job Designer Notes

Project description Job description Designer’s initials Job notes

(50 Char) (50 Char) (3 Char) (1024 Char)

If any of the heading lines have no data then they should be entered as just a pair of quotes (eg. "") rather than just being a blank line. See also Headings.

188

Text File Input

Nodes text Line 1: NODES Next n Node,X,Y,Z,Gen1,Ndi1,Rot,Ai,Xi1,Yi1,Zi1, lines: Gen2,Ndi2,Xi2,Yi2,Zi2 Node X Y Z Gen1 Ndi1 Rot Ai Xi1 Yi1 Zi1 Gen2 Ndi2 Xi2 Yi2 Zi2

Node number X coordinate Y coordinate Z coordinate # of 1st order nodes to be generated 1st order node number increment Axis of rot. for arc or helix generation (X/Y/Z) Angle increment for arc or helix generation 1st order X increment 1st order Y increment 1st order Z increment # of 2nd order nodes to be generated 2nd order node number increment 2nd order X increment 2nd order Y increment 2nd order Z increment

(Integer) (Real) (Real) (Real) (Integer) (Integer) (1 Char) (Real) (Real) (Real) (Real) (Integer) (Integer) (Real) (Real) (Real)

For straight line generation, Ai should be zero. For arc or helix generation, Rot is the axis of rotation, Ai is the angle increment and Xi1, Yi1, Zi1 are the centre of rotation and the helix length increment. For example, if a helix is generated about the Y-axis, then Yi1 is the helix length increment. For arc generation the helix length increment is 0. Rot choices are "X"=X-axis, "Y"=Y-axis, "Z"=Z-axis. See also Nodes.

189


Members text Line 1: Next n lines:

MEMBERS Mem,DirAng,DirNode,DirAxis,Type,Na,Nb,Sp,Mp, Fa,Fb,Ya,SZa,SYb,SZb,Cab,Gen1,Mbi1,Nai1,Nbi1, Gen2,Mbi2,Nai2,Nbi2

Mem DirAng DirNode DirAxis Type Na Nb Sp Mp Fa Fb SYa SZa Syb SZb Cab Gen1 Mbil Nail Nbil Gen2 Mbi2 Nai2 Nbi2

Member number Direction angle Direction node Direction axis Member type (N/T/C/A) Node number A Node number B Section property number Material property number Node A fixity (F/R/S) Node B fixity (F/R/S) Y rotational stiffness at node A Z rotational stiffness at node A Y rotational stiffness at node B Y rotational stiffness at node B Cable length # of 1st order members to be generated 1st order member number increment 1st order node A increment 1st order node B increment # of 2nd order members to be generated 2nd order member number increment 2nd order node A increment 2nd order node B increment

(Integer) (Real) (Integer) (2 Char) (1 Char) (Integer) (Integer) (Integer) (Integer) (6 Char) (6 Char) (Real) (Real) (Real) (Real) (Real) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer)

Type choices are "N"=Normal, "T"=Tension-only, "C"=Compression-only, "A"=Cable. Fa, Fb choices are "F"=Fixed, "R"=Released. "S"=Spring can also be used for the y and z rotational fixities. See also Members.

190

Text File Input

Plates text Line 1: Next n lines:

PLATES Plate,DirAng,DirNode,DirAxis,Type,Na,Nb,Nc,Nd, TA,TM,TB,TS,Mat,Offset,Gen,PInc,NInc

Plate DirAng DirNode DirAxis Type Na Nb Nc Nd TA TM TB TS Mat Offset Gen PInc NInc

Plate number Direction angle Direction node Direction axis Plate type (K/M) Node number A Node number B Node number C Node number D Actual thickness Membrane thickness Bending thickness Shear thickness Material property number Plate offset # of plates to be generated Plate number increment Node number increment

(Integer) (Real) (Integer) (2 Char) (1 Char) (Integer) (Integer) (Integer) (Integer) (Real) (Real) (Real) (Real) (Integer) (Real) (Integer) (Integer) (Integer)

Type choices are "K"=Kirchoff (thin), "M"=Mindlin (thick). See also Plates.

191


Node restraints text Line 1: RESTRAINTS Next n Node,Rest,Gr,Gen,NInc,Ax,Ay,Az,Rx,Ry,Rz lines: Node Rest Gr Gen NInc Ax Ay Az Rx Ry Rz

Node number Restraint code (F/R/D/S) General restraint (Y/N) # of restrained nodes Node number increment X axial spring stiffness Y axial spring stiffness Z axial spring stiffness X rotational spring stiffness Y rotational spring stiffness Z rotational spring stiffness

Rs choices are "F"=Fixed, "R"=Released, "D"=Deleted, "S"=Spring. Gr choices are "Y"=General restraint, " " or "N"=Normal restraint. See also Node restraints.

192

(Integer) (6 Char) (1 Char) (Integer) (Integer) (Real) (Real) (Real) (Real) (Real) (Real)

Text File Input

Section properties text Line 1: Next n sets of lines: Next set of 3 lines per shape: Next set of "Points" lines per shape: Sec Secn

SECTIONS Sec,Secn,Lib,Mark,Ar,Ix,Iy,Iz,Ay,Az,Pa,Shapes ShapeType,Points,Dims Void,Parent,Transpose,Mirror,TransX,TransY,Rotate,Fabrication Strengths X,Y,Z

Section property number Section name

Section library name Lib Section mark Mark Area of section Ar Torsion constant Ix Y principal moment of inertia Iy Z principal moment of inertia Iz Y shear area Ay Z shear area Az Principal angle Pa The number of shapes in the section Shapes ShapeType Shape type (0=Undefined, 1=Rod, 2=Square, 3=Flat, 4=CHS, 5=SHS, 6=RHS, 7=I-shape, 8=PWG, 9=Channel, 10=Beam Tee, 11=Column Tee, 12=Equal Angle, 13=Unequal Angle, 14=Cruciform, 15=Box Girder, 16=Wedge, 17=Slice, 18=Fillet, 19=Points, 20=LSB, 21=LSB/B2B, 22=Lines, 23=Triangle, 24=Cee, 25=Zed, 26=Top Hat, 27=DA/Short, 28=DA/Long, 29=DA/Starred, 30=Polygon, 31=PolyTube, 32=Equilateral Triangle, 33=Schifflerized Angle, 34=Back to Back Cee, 35=Rounded Angle, 36=Rack, 37=L-shape, 38=Trapezoid, 39=Flat Oval) The number of perimeter points in a points shape or line shape Points The shape dimensions (D,Bt,Bb,Btw,Bbw,Tt,Tb,Tw,Hf,Rr) Dims 1=Void shape (hole), otherwise 0 Void Parent shape if Void=1 Parent Transpose 1=Transposed shape, otherwise 0 1=Mirrored about X, 2=Mirrored about Y, 3=Mirrored about both, Mirror otherwise 0 Translation distance along X TransX Translation distance along Y TransY Rotation angle (degrees) Rotate Fabrication Fabrication code (0=Hot rolled, 1=Stress relieved, 2=Lightly welded, 3=Heavily welded, 4=Cold formed, 5=Cold formed and stress relieved) Strengths Material strengths (Fy,Fyw,Fu for up to 6 grades of steel) Coordinates of perimeter points in a points shape or line shape X,Y,Z

(Integer) (15 Char) (8 Char) (5 Char) (Real) (Real) (Real) (Real) (Real) (Real) (Real) (Integer) (Integer)

(Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer)

(Integer) (Integer)

See also Section properties.

193


Material properties text Line 1: MATERIALS Next n lines: Mat,Matl,E,Pr,D,T,Fc Mat Matl Lib E Pr D T Fc

Material property number Material name Material library name Young’s modulus Poisson’s ratio Mass density Coefficient of thermal expansion Characteristic concrete strength

See also Material properties.

194

(Integer) (15 Char) (8 Char) (Real) (Real) (Real) (Real) (Real)

Text File Input

Master-slave constraints text Line 1: CONSTRAINTS Next n lines: SNode,MNode,Cnst,Gen,SInc,MInc SNode MNode Cnst Gen SInc MInc

Slave node number Master node number Constraint code (F/R) # of slave nodes to be generated Slave node number increment Master node number increment

(Integer) (Integer) (6 Char) (Integer) (Integer) (Integer)

Cc choices are "F"=Fixed, "R"=Released. See also Master-slave constraints.

195


Member offset text Line 1: Next n lines:

OFFSETS Mem,Ax,Dxa,Dya,Dza,Dxb,Dyb,Dzb

Mem Ax Dxa Dya Dza Dxb Dyb Dzb

Member number Axes system (L/G) Member offset from A along x-axis Member offset from A along y-axis Member offset from A along z-axis Member offset from B along x-axis Member offset from B along y-axis Member offset from B along z-axis

Ax choices are "L"=Local, "G"=Global. See also Member offsets.

196

(Integer) (1 Char) (Real) (Real) (Real) (Real) (Real) (Real)

Text File Input

Node loads text Line 1: NODELOADS Next n Case,Node,Fx,Fy,Fz,Mx,My,Mz,Gen,NInc lines: Case Node Fx Fy Fz Mx My Mz Gen NInc

Load case number Node number X force Y force Z force X moment Y moment Z moment # of loaded nodes to be generated Node number increment

(Integer) (Integer) (Real) (Real) (Real) (Real) (Real) (Real) (Integer) (Integer)

See also Node loads.

197


Prescribed node displacements text Line 1: NODEDISPS Next n Case,Node,Tx,Ty,Tz,Rx,Ry,Rz,Gen,NInc lines: Case Node Tx Ty Tz Rx Ry Rz Gen NInc

Load case number Node number X translation Y translation Z translation X rotation Y rotation Z rotation # of displaced nodes to be generated Node number increment

See also Prescribed node displacements.

198


Text File Input

Member concentrated loads text Line 1: MEMBCONC Next n Case,Mem,Sl,Ax,Un,Ps,Fx,Fy,Fz,Mx,My,Mz, lines: Gen1,MInc,Gen2,SInc,PInc Case Mem Sl Ax Un Ps Fx Fy Fz Mx My Mz Gen1 MInc Gen2 SInc PInc

Load case number Member number Sub load number Axes system (L/G) Units system (A/%) Load position X force Y force Z force X moment Y moment Z moment # of loaded members to be generated Member number increment # of loads per member to be generated Sub load number increment Load position increment

(Integer) (Integer) (Integer) (1 Char) (1 Char) (Real) (Real) (Real) (Real) (Real) (Real) (Real) (Integer) (Integer) (Integer) (Integer) (Real)

Ax choices are "L"=Local, "G"=Global. Un choices are "A"=Actual, "%"=Percentage. See also Member concentrated loads.

199


Member distributed forces text Line 1: MEMBFORCES Next n Case,Mem,Sl,Ax,Un,St,Fi,Xs,Xf,Ys,Yf,Zs,Zf, lines: Gen,MInc Case Mem Sl Ax Un St Fi Xs Xf Ys Yf Zs Zf Gen MInc

Load case number Member number Sub load number Axes system (L/G/A) Units system (A/%) Start position Finish position X start force X finish force Y start force Y finish force Z start force Z finish force # of loaded members to be generated Member number increment

Ax choices are "L"=Local, "G"=Global-projected, "A"=Global-inclined. Un choices are "A"=Actual, "%"=Percentage. See also Member distributed forces.

200

(Integer) (Integer) (Integer) (1 Char) (1 Char) (Real) (Real) (Real) (Real) (Real) (Real) (Real) (Real) (Integer) (Integer)

Text File Input

Member distributed torsions text Line 1: MEMBTORSION Next n Case,Mem,Sl,Un,St,Fi,Ts,Tf,Gen,MInc lines: Case Mem Sl Un St Fi Ts Tf Gen MInc

Load case number Member number Sub load number Units system (A/%) Start position Finish position Start torsion Finish torsion # of torsion loads to be generated Member # increment

(Integer) (Integer) (Integer) (1 Char) (Real) (Real) (Real) (Real) (Integer) (Integer)

Un choices are "A"=Actual, "%"=Percentage. See also Member distributed torsions.

201


Thermal loads text Line 1: Next n lines:

THERMAL Case,Elem,Type,Temp,GradY,GradZ,Gen,EInc

Case Elem Type Temp GradY GradZ Gen EInc

Load case number Element number Element type (M/P) Temperature change Reserved (must be set to 0.0) Plate thermal gradient # of thermal loads to be generated Element # increment

Type choices are "M"=Member, "P"=Plate. See also Thermal loads.

202

(Integer) (Integer) (1 Char) (Real) (Real) (Real) (Integer) (Integer)

Text File Input

Member prestress loads text Line 1: Next n lines:

PRESTRESS Case,Mem,Force,Gen,MInc

Case Mem Force Gen MInc

Load case number Member number Prestress force # of prestress loads to be generated Member # increment

(Integer) (Integer) (Real) (Integer) (Integer)

See also Member prestress.

203


Plate pressure loads text Line 1: Next n lines:

PRESSURE Case,Plate,Px,Py,Pz,Gen,PInc

Case Plate Ax Px Py Pz Gen PInc

Load case number Plate number Axes system (L/G/A) X pressure Y pressure Z pressure # of loaded plates to be generated Plate number increment

(Integer) (Integer) (1 Char) (Real) (Real) (Real) (Integer) (Integer)

Ax choices are "L"=Local, "G"=Global-projected, "A"=Global-inclined. See also Plate pressure.

204

Text File Input

Self weight text Line 1: Next n lines:

SELFWEIGHT Case,Ax,Ay,Az

Case Ax Ay Az

Load case number X acceleration Y acceleration Z acceleration

(Integer) (Real) (Real) (Real)

See also Self weight.

205


Combination load cases text Line 1: Next n lines:

COMBINATIONS Comb,Case,Fact

Comb Case Fact

Combination load case number (Integer) Load case number (primary or combination) (Integer) Multiplying factor (Real)

See also Combination load cases.

206

Text File Input

Load case titles text Line 1: Next n lines:

TITLES Case,Title,Notes

Case Title Notes

Load case number Load case title Load case notes

(Integer) (50 Char) (255 Char)

See also Load case titles.

207


Lumped masses text Line 1: LUMPEDMASS Next n Case,Node,Tx,Ty,Tz,Rx,Ry,Rz,Gen,NInc lines: Case Node Tx Ty Tz Rx Ry Rz Gen NInc

Load case number Node number X translational mass Y translational mass Z translational mass X rotational mass Y rotational mass Z rotational mass # of loaded nodes to be generated Node number increment

See also Lumped masses.

208


Text File Input

Spectral loads text Line 1: Next n lines:

SPECTRAL Case,Mode,Curve,MCase,Dx,Dy,Dz

Case Mode Curve MCase Dx Dy Dz

Load case number Mode shape Spectral curve name Mass case X direction vector Y direction vector Z direction vector

(Integer) (Integer) (50 Char) (Integer) (Real) (Real) (Real)

See also Spectral loads.

209


Steel member design text Line 1: Next n lines:

STEELMEMBERS Group,Title,MList,SGrade,Units,LoadHeight, ScanCode,CalcLcMjr,LcMjr,BraceMjr,CalcLcMnr, LcMnr,BraceMnr, CalcLb,Lb+,Lb-,TopPos, TopRest,BotPos,BotRest, Ast,EndCon, EccEffect,Criteria,Bolts,Dia,ISSeismicCat,NZSeismicCat, MemberType,Cantilever,Gen,GInc,MInc

Group Title MList SGrade Units LoadHeight ScanCode CalcLcMjr LcMjr BraceMjr CalcLcMnr LcMnr BraceMnr CalcLb Lb+ LbTopPos TopRest BotPos BotRest Ast EndCon EccEffect Criteria Bolts Dia ISSeismicCat NZSeismicCat MemberType Cantilever Gen GInc MInc

Group number Group title List of analysis members in the group Strength grade (N/H) Units system (A/R) Load height position (C/T) Library scan code Calculate LcMjr from a buckling analysis (Y/N) Major axis compression effective length Major axis braced in position at both ends of group (Y/N) Calculate LcMnr from a buckling analysis (Y/N) Minor axis compression effective length Minor axis braced in position at both ends of group (Y/N) Calculate Lb+ and Lb- (Y/N) Positive bending effective length Negative bending effective length List of restraint positions (intermediate only) on top flange List of restraint types (end and intermediate) on top flange List of restraint positions (intermediate only) on bottom flange List of restraint types (end and intermediate) on bottom flange Angle section type (A/S/L/X) End connection type (C/F/W/S/L) Consider eccentric effects (Y/N) Design criteria (W/D) Maximum number of bolts in cross section (0=Welded) Bolt diameter Indian IS800 seismic category New Zealand NZS3404 seismic category Member type (for seismic checks) Reserved for a future version Number of groups to be generated Group number increment Member number increment

SGrade choices are "N"=Normal strength, "H"=High strength. Units choices are "A"=Actual, "R"=Ratio. LoadHeight choices are "C"=Shear centre or below, "T"=Top flange.

210

(Integer) (50 Char) (50 Int) (1 Char) (1 Char) (1 Char) (4 Char) (1 Char) (Real) (1 Char) (1 Char) (Real) (1 Char) (1 Char) (Real) (Real) (50 Real) (52 Char) (50 Real) (52 Char) (1 Char) (1 Char) (1 Char) (1 Char) (Integer) (Real) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer) (Integer)

Text File Input CalcLcMjr choices are "Y"=Calculate LcMjr from a buckling analysis, "N"=Use the input value of LcMjr. BraceMjr choices are "Y"=Both ends of the design group are braced in position for buckling about the major axis, "N"=Either or both ends of the design group are not braced in position for buckling about the major axis. CalcLcMnr choices are "Y"=Calculate LcMnr from a buckling analysis, "N"=Use the input value of LcMnr. BraceMnr choices are "Y"=Both ends of the design group are braced in position for buckling about the minor axis, "N"=Either or both ends of the design group are not braced in position for buckling about the minor axis. CalcLb choices are "Y"=Calculate Lb+ and Lb- from the flange restraints, "N"=Use the input values of Lb+ and Lb-. TopPos and BotPos are lists of the intermediate flange restraint positions which can include @ multipliers but not dashes. For example, restraint positions 1.2,3.0,4.8,6.6,8.4,10.2,11.4 could be listed as 1.2,[email protected],[email protected] or 1.2,[email protected],11.4. TopRest and BotRest must be a string of characters without commas, dashes or @’s. For example FLLPLR. Ast choices are "A"=Single angle, "S"=Double angle with short legs connected, "L"=Double angle with long legs connected, "X"=Double starred angle. Ast is only considered if the section is an angle section. EndCon choices are "C"=Centroid, "F"=Flange, "W"=Web, "S"=Angle short leg, "L"=Angle long leg. EccEffect choices are "Y"=Consider end connection eccentric effects, "N"=Ignore eccentric effects. Criteria choices are "W"=Use weight design criteria, "D"=Use depth design criteria. ISSeismicCat choices are 0=Non-seismic, 1=Ordinary concentrically braced frame, 2=Special concentrically braced frame, 3=Ordinary moment frame, 4=Special moment frame. NZSeismicCat choices are 0=Non-seismic, 1=Category 1 member, 2=Category 2 member, 3=Category 3 member, 4=Category 4 member. MemberType choices are 0=Non-specific, 1=Beam, 2=Column, 3=Brace. Cantilever is reserved for a future version and should be set to 0. See also Steel member design data.

211


Terminator Line 1:

212

END

Text File Input

Text file errors Error messages which may occur while a text file is being read by SPACE GASS are as follows. Illegal or missing numeric value Essential real or integer numeric value has been omitted or is beyond the problem size limits. Illegal data encountered Unexpected data type was encountered (eg. integer instead of real). Title line not recognised Incorrect data group title has been detected (eg. NEDES instead of NODES). Generation data out of limits Items to be generated would exceed the problem size limits. Change the generation data or choose "Problem size limits" from the Config menu and increase the limits. Illegal or missing character Illegal character detected or expected character not found. Maximum limit exceeded One of the problem size limits has been exceeded. Choose "Problem size limits" from the Config menu and increase the limits. Library not found The standard sections or materials library cannot be found. Wrong format library The standard sections or materials library is in an invalid or old format and cannot be read. Section or material not found Specified section or material name cannot be found in specified library. Demonstration version limit exceeded The demonstration version of the program allows only 1 section property, 1 material property, 5 steel design groups, and 1 steel design connection. Not a valid SPACE GASS text file The file does not have a valid SPACE GASS text file format or the first line does not indicate that it is SPACE GASS data. Restraint positions are not in ascending order The intermediate flange restraint positions must be in ascending order. Restraint positions do not match types The number of intermediate flange restraint positions must match the number of restraint types less the two end restraint types. Each use of an @ multiplier in a restraint positions list must have only one corresponding restraint type. L or C restraint is ineffective A Lateral restraint type must have Full or Partial restraint types between it and the end of the design group on both sides to be effective. A Continuous restraint type must be between Full, Partial or Lateral restraint types to be effective. 213


Ignored segments must be at ends You have specified an ignored segment at an intermediate position along the group. Segments to be ignored must be at either or both ends of the group only. Require intermediate restraint positions only Restraint positions should be specified for the intermediate restraints only. SPACE GASS already knows the positions of the restraints at the ends of the group. 100 members per design group limit exceeded A steel member design group cannot contain more than 100 members. 100 cases per combination limit exceeded A combination load case cannot contain more than 100 primary load cases. 100 flange restraints limit exceeded A steel member design group cannot contain more than 100 flange restraints per flange. No members in steel design group A steel member design group must consist of at least one analysis member. Restraint position exceeds maximum distance A flange restraint has been positioned beyond the length of the steel member design group. Illegal or missing restraint type An illegal character has been detected in the steel member design restraint types field or the restraint type is missing. Comma is missing A list of numbers is missing a comma. There must be a value between separators A list of values has two adjacent commas, dashes or @’s. Too many values in list A list of numbers contains too many values. Cannot use "-" range in this data field You are not permitted to use dashes in this list of integers. Cannot use "@" multiplier in this data field You are not permitted to use @’s in this list of numbers. Multiplier must be an integer The number before an @ in a list of numbers must be an integer. Cannot have a repeated member The same member has been referenced twice in a single connection. Must have at least one supported member All connection types require at least one supported member. An apex connection must be the same on both sides If you have specified one side of a connection to be an apex then you must use exactly the same connection type for the other side. 214

Text File Input

An internal stiff seat must be the same on both sides If you have specified one side of a connection to be an internal stiff seat then you must use exactly the same connection type for the other side. This connection requires two supported members Apex and internal stiff seat connections require two supported members. This connection requires only one supported member Baseplate connections must have only one supported member. It doesn’t matter whether the supported member is specified as side A or side B. This connection requires a supporting member A supporting member is always required (except for apex, stiff seat or baseplate). This connection requires no supporting member Apex and baseplate connections cannot have a supporting member. No connection type specified You have not specified a valid connection type for one of the supported members. Supported member not specified You have not specified a supported member for one of the connection types. Invalid bolting procedure for connection type A snug bolting procedure cannot be used in bolted end plate, apex or moment baseplate connections, use bearing or friction bolting procedures. Haunches are only for B.E.P, welded moment or apex Haunches are supported only in bolted end plate, apex and welded moment connections. Invalid bolt strength for bolting procedure specified Normal strength bolts cannot be tensioned for bearing or friction bolting procedures. Use high strength bolts. Stiff seat bearing length required Because you have not specified a supporting member for the stiff seat connection, the bearing length cannot be calculated by SPACE GASS. Specify a supporting member or a stiff seat bearing length (or both). Cannot have fillet weld for welded apex connection Welded apex connections require butt welds for the flanges. Must have the same bolting procedure on each side You must specify the same bolting procedure on both sides of an apex or internal stiff seat connection. Cannot have a haunch on only one side of an apex If you have specified a haunch on one side of an apex connection then you must also specify a haunch on the other side. Must have the same haunch depth on each side of an apex Apex connections require the same haunch depth on both sides.

215


Text file example The following sample text file contains all of the data for the worked example used in the appendices at the end of this manual. SPACE GASS Text File - Version 900 UNITS LENGTH:m, SECTION:m, STRENGTH:kPa, DENSITY:T/m^3, TEMP:Celsius, & FORCE:kN, MOMENT:kNm, MASS:T, ACC:m/sec^2, TRANS:m, STRESS:kPa HEADINGS "SPACE GASS Worked Example" "25m Single Span Portal Frame" "PS" "" NODES 1,0.000,0.000 2,0.000,3.750 3,0.000,7.500 4,1.630,7.585 5,3.260,7.671 6,6.250,7.828 7,12.500,8.155 8,18.750,7.828 9,21.740,7.671 10,23.370,7.585 11,25.000,7.500 12,25.000,3.750 13,25.000,0.000 MEMBERS 1,0.00,0, ,N,1, 2,1,1,FFFFFF,FFFFFF 2,0.00,0, ,N,2, 3,1,1,FFFFFF,FFFFFF 3,0.00,0, ,N,3, 4,3,1,FFFFFF,FFFFFF 4,0.00,0, ,N,4, 5,4,1,FFFFFF,FFFFFF 5,0.00,0, ,N,5, 6,2,1,FFFFFF,FFFFFF 6,0.00,0, ,N,6, 7,2,1,FFFFFF,FFFFFF 7,0.00,0, ,N,7, 8,2,1,FFFFFF,FFFFFF 8,0.00,0, ,N,8, 9,2,1,FFFFFF,FFFFFF 9,0.00,0, ,N,9,10,4,1,FFFFFF,FFFFFF 10,0.00,0, ,N,10,11,3,1,FFFFFF,FFFFFF 11,0.00,0, ,N,11,12,1,1,FFFFFF,FFFFFF 12,0.00,0, ,N,12,13,1,1,FFFFFF,FFFFFF RESTRAINTS 1,FFFFFR 2,RRFFFR,Y 13,FFFFFR SECTIONS 1,"530 UB 2,"360 UB 3,"360 UB 4,"360 UB

92","AUST250", ,"C1" 51","AUST250", ,"R1" 51-A","", ,"HNCH ",N,0.10773E-01,0.472E-06,0.14524E-04,0.63586E-03 51-B","", ,"S4 ",N,0.96446E-02,0.472E-06,0.14519E-04,0.36376E-03

MATERIALS 1,"STEEL","METRIC" NODELOADS 2,7,0.0,-4.5 MEMBFORCES 1,3,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,4,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,5,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,6,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,7,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,8,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,9,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 1,10,1,A,%,0.0,100.0,0.0,0.0,-0.9,-0.9 2,3,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 2,4,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 2,5,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 2,6,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 2,7,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 2,8,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 2,9,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250

216

Text File Input 2,10,1,G,%,0.0,100.0,0.0,0.0,-2.250,-2.250 3,1,1,G,%,0.0,100.0,6.300,6.300,0.0,0.0 3,2,1,G,%,0.0,100.0,6.300,6.300,0.0,0.0 3,3,1,L,%,0.0,100.0,0.0,0.0,6.480,6.480 3,4,1,L,%,0.0,100.0,0.0,0.0,6.480,6.480 3,5,1,L,%,0.0,100.0,0.0,0.0,6.480,6.480 3,6,1,L,A,0.0,1.7410,0.0,0.0,6.480,6.480 3,6,2,L,A,1.7410,6.2590,0.0,0.0,3.600,3.600 3,7,1,L,A,0.0,3.4820,0.0,0.0,3.600,3.600 3,7,2,L,A,3.4820,6.2590,0.0,0.0,2.160,2.160 3,8,1,L,%,0.0,100.0,0.0,0.0,2.160,2.160 3,9,1,L,%,0.0,100.0,0.0,0.0,2.160,2.160 3,10,1,L,%,0.0,100.0,0.0,0.0,2.160,2.160 3,11,1,G,%,0.0,100.0,4.500,4.500,0.0,0.0 3,12,1,G,%,0.0,100.0,4.500,4.500,0.0,0.0 4,1,1,L,%,0.0,100.0,0.0,0.0,4.140,4.140 4,2,1,L,%,0.0,100.0,0.0,0.0,4.140,4.140 4,3,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,4,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,5,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,6,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,7,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,8,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,9,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,10,1,L,%,0.0,100.0,0.0,0.0,5.040,5.040 4,11,1,L,%,0.0,100.0,0.0,0.0,4.140,4.140 4,12,1,L,%,0.0,100.0,0.0,0.0,4.140,4.140 5,1,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,2,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,3,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,4,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,5,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,6,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,7,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,8,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,9,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,10,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,11,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 5,12,1,L,%,0.0,100.0,0.0,0.0,1.440,1.440 6,1,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,2,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,3,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,4,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,5,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,6,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,7,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,8,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,9,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,10,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,11,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 6,12,1,L,%,0.0,100.0,0.0,0.0,4.680,4.680 7,1,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,2,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,3,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,4,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,5,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,6,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,7,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,8,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,9,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,10,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,11,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 7,12,1,L,%,0.0,100.0,0.0,0.0,0.9,0.9 SELFWEIGHT 1,0.0,-9.807E-03,0.0 COMBINATIONS 10,1,1.25 10,2,1.50 11,1,0.80 11,3,1.00 11,6,1.00 12,1,1.25 12,3,1.00 12,6,-0.96 13,1,0.80 13,4,1.00 13,7,1.00 14,1,1.25 14,5,1.00 14,7,-6.50

217


TITLES 1,Dead load (DL) 2,Live load including 4.5kN at ridge (LL) 3,Cross wind (CW) 4,Longitudinal wind at first internal frame (LW1) 5,Longitudinal wind with 0.2 external suction (LW2) 6,Cross wind internal pressure (IPCW) 7,Longitudinal wind internal pressure (IPLW) 10,1.25DL+1.5LL 11,0.8DL+CW+IPCW 12,1.25DL+CW+ISCW 13,0.8DL+LW1+IPLW 14,1.25DL+LW2+ISLW STEELMEMBERS 1,"","1,2",N,A,C,A ,N,20.0,1.7,Y,1.0,1.0, & "1.2,2.4,3.6,5.3,7",RLLLLFIF,"",RF,N,N,A,C,Y,W,0,0.02 2,"","5,6",N,A,C,A ,N,12.517,1.2,Y,1.0,1.0, & "1.3,2.5,3.7,4.9,6.1,7.3,8.1",RLLLLLLLF,"4.9",RLF,N,N,A,C,Y,W,0,0.02 3,"","8,7",N,A,C,A ,N,12.517,1.2,Y,1.0,1.0, & "1.3,2.5,3.7,4.9,6.1,7.3,8.1",RLLLLLLLF,"4.9",RLF,N,N,A,C,Y,W,0,0.02 4,"","12,11",N,A,C,A ,N,20.0,1.7,Y,1.0,1.0, & "1.2,2.4,3.6,5.3,7",RLLLLFIF,"",RF,N,N,A,C,Y,W,0,0.02 STEELCONNECT 1,"Left baseplate",0,1,0,8,0,S,S,0.0,0.0,0.0,0.0, & H,N,N,N,N,0.07,0.07,0.0,H,S,0,Y,Y,S,G,B,T 2,"Left eave",2,0,3,0,1,S,B,0.0,0.0,3.0,0.0, & H,N,N,N,N,0.07,0.07,0.0,H,S,0,Y,Y,S,G,B,T 6,"Bolted apex",0,6,7,2,2,B,B,0.0,0.0,0.0,0.0, & H,N,N,N,N,0.07,0.07,0.0,H,S,0,Y,Y,S,G,B,T 11,"Right eave",11,10,0,3,0,S,S,3.0,0.0,0.0,0.0, & H,N,N,N,N,0.07,0.07,0.0,H,S,0,Y,Y,S,G,B,T 12,"Right baseplate",0,0,12,0,8,S,S,0.0,0.0,0.0,0.0, & H,N,N,N,N,0.07,0.07,0.0,H,S,0,Y,Y,S,G,B,T END

218

Structure Wizard Structure wizard You can open the structure wizard by clicking the wizard" from the Structure menu.

toolbar button or selecting "Structure

Structure wizard input provides a very fast means of inputting data into SPACE GASS for structures that conform generally to one of the standard structures shown above. The structure wizard input method can still be used for structures which don’t conform exactly to the structures shown above. In such cases it can be used to input the basic structure and then modified by one of the other data entry methods. For example, a portal frame with its apex off centre could be initially input as a symmetrical portal frame using the structure wizard and then modified graphically by moving the apex node to its correct location. Once a structure has been selected, a structure specific form is opened which allows you to input basic data relating to the frame geometry, supports, pattern loads, etc. SPACE GASS will then generate the structure, and apply any pattern loading, automatically. The input form for a single bay portal frame is shown below.

219


Important note regarding restraints applied to wizard generated models For all 2D frames generated by the structure wizard, out-of-plane translations on some nonsupport nodes are restrained. This has two major implications that you should be aware of. 1. If you extend the frame to 3D after it has been generated then the 2D restraints may no longer be appropriate. If this is the case, you should modify or delete them.

2. Even though a frame is 2D, it may often be appropriate to allow some nodes to move and/or rotate in the out-of-plane direction. This is especially the case if a buckling or dynamic frequency analysis is to be performed where out-of-plane movements can occur even when there are no loads in that direction. Because of this, you may have to modify the restraints generated by the structure wizard to allow these movements. Conversely, you may have to apply more out-of-plane restraints if those movements are prevented in your real structure. For more information, refer to Node restraint data and, in particular, the section entitled "Important note about restraining 2D frames".

220

Portal Frame Builder Portal frame builder This tool lets you generate all of the structural, load and design data for a complete portal frame building. You can then go ahead and analyse and design it using the normal analysis and design tools available in SPACE GASS. It supports gable (symmetrical and asymmetrical) and monoslope roofs, overhangs, knee braces, haunches, fly bracing, uneven frame spacings, openings, roof/wall bracing and end wall props. Wind loads are generated in accordance with AS/NZS 1170.2:2011 for all regions in Australia and New Zealand. They are calculated for each direction based on the region, average recurrence interval, terrain category (including transition zones), shielding and topography. Openings can be allowed for by specifying minimum and maximum internal Cp,i pressure coefficients for each wind direction. Wall loads can be applied to the columns (the normal situation) or to the eave ties and end frame rafters for buildings that have tilt-up panels. Load cases are automatically generated for all combinations of the dead, live and wind loads. You can access the portal frame builder tool from within the renderer by clicking the button or by selecting "Portal frame builder" from the Structure menu. Note that if you haven't purchased the portal frame builder tool, you can still run it in a free trial mode that limits you to a pre-defined building width and height, and prevents you from exporting or saving the job. All other features are fully activated. A video showing the portal frame builder in action can be viewed at www.spacegass.com/portal.

221

SPACE GASS 12 User Manual Refer to Geometry, Extra data, Sections and materials, Loads, Load cases or Design for more details about the input parameters.

222

Portal Frame Builder

Portal frame geometry This form lets you define the basic geometric data for the portal frame building.

Options The basic options are largely self-explanatory, however some of the less obvious ones are explained in more detail below.

If "Define eaves height by" is set to "Sheeting intersection" then the height is measured from the footing to the intersection point of the wall and roof sheeting. Otherwise it is measured to the "Springing height", which is the underside of the rafter (or haunch if one exists) at the face of the column. Eave and ridge ties are extended down the full length of the building, whereas end frame prop ties are placed just between the end frame and the first internal frame at each end of the building wherever there is a prop.

223

SPACE GASS 12 User Manual Gridlines and dimensions can be generated automatically if ticked. You can also edit them or add extra dimensions manually using the renderer's normal gridline and dimensioning tools. If you tick "Align column outside flanges" and the end frame columns are different to the internal frames then the columns will be adjusted so that their outside flanges line up down the length of the building. If unticked, the columns will be aligned via their centroids. The "Connect rafter props to bottom flange" option lets you decide between connecting the props to the rafter centerline or to the bottom flange. If connected to the centerline the connection is pin-ended, whereas if connected to the bottom flange the connection is rigid. The reason for the rigid connection is to prevent shear force in the prop generating torsion in the rafter and potentially causing it to fail unrealistically. Geometry All dimensions in the geometry fields are relative to the sheeting lines.

Bay spacings and bracing The frames are assumed to be equally spaced by default, however you can change the spacings as required. The bay spacings are to the frame centroids and will affect the overall length of the building if you change them.

Purlin and girt details Purlins and girts are not added to the model as actual members, however they are included in the steel member design data as flange restraints. The purlin and girt depths are required so that the frame positions can be calculated relative to the sheeting lines. For gable frames, the purlins on each rafter are equally spaced with the first purlin positioned 200mm from the ridge. For monoslope frames, the purlins equally spaced and centered between the columns. The girts are equally spaced with the first girt positioned 200mm from the footing.

224

Portal Frame Builder Fly braces can be positioned at every 2nd, 3rd, etc... purlin or girt as specified by you. Of course you can manually adjust the purlin, girt and fly brace data to suit your exact requirements via the steel member design input data once the model has been generated.

225


Portal frame extra data This form lets you input the end frame props, bracing, knee braces, haunches and the position of the model.

End frame props and bracing This table allows you to specify the props and bracing for the front and rear walls. If the front and rear walls have identical data then you can input the data for one wall and then click the "Duplicate at Front/Rear" button. Prop positions can be input as actual values or as percentages of the end frame width relative to the column centroids. Alternatively, you can click the "Generate End Frame Props" button to quickly generate equally spaced props with or without bracing.

226


Knee braces and haunches You can specify knee braces or haunches in the internal and/or end frames using the following fields. The knee brace length is the horizontal distance from the face of the column, while its height is the vertical distance from the intersection of the centroids of the column and rafter. The haunch length is the horizontal distance from the face of the column.

Positioning and numbering By default, the model is generated with its front-left corner at the global origin, however you can control this with the X,Y,Z position fields. This is especially useful if you are adding the generated model to an existing structure in your job. The nodes, members and load cases use the next available numbers unless you specify starting numbers in the "Start..." fields. 227


Connections The portal frame builder can also generate all of the main connections in the building. All you need to do is specify the type of connection to be used for the knees, ridges and baseplates. These can then be designed or checked in the steel connection design module.

228


Portal frame sections and materials This form lets you define the section and material properties of the various components of the building.

229


Portal frame loads This form lets you define the dead load, live load and wind load generation parameters.

Dead and live loads The "Roof sheeting and purlin dead load" is a permanent load that is applied to all load combinations, whereas the "Services and superimposed dead load" is considered to be a temporary load that is only applied to the downward load combinations. The dead loads you input are applied to the actual roof area, while the live load is applied to the plan projection of the roof area. If you tick the "Calculate" live load option then it will be calculated based on the maximum of 0.25 and 1.8/A + 0.12 kPa as given in AS/NZS 1170.1 table 3.2. Note that the distributed live load is applied to the entire roof area, even if the roof area is greater than 200m^2. The 1.4kN concentrated live load specified in AS/NZS 1170.1 (but not in conjunction with the distributed live load - see AS/NZS 1170.1 section 3.1) is not applied.

230

Portal Frame Builder Wind loads Wind loads can be calculated for any region in Australia or New Zealand. The average recurrence intervals (ARIs) for the ultimate and serviceability limit states are used to calculate the regional wind speeds from AS/NZS 1170.2 table 3.1.

Wind directions If you tick the "Apply same wind in all directions" option then you are only required to input one set of wind data for the shielding, topographic, terrain category and internal pressure parameters. Otherwise, these data must be defined for each of the four orthogonal building axes.

Shielding multiplier (Ms) The shielding multiplier (see AS/NZS 1170.2 section 4.3) takes into account shielding provided by other upwind buildings or structures. It is 1.0 if there is no shielding. You can enter the desired value directly or you can click the "Calculate" button and then input various shielding parameters and have Ms calculated for you. The ns, hs, bs and h values and the calculation of Ms are all explained in AS/NZS 1170.2 section 4.3.

Topographic multiplier (Mt) The topographic multiplier (see AS/NZS 1170.2 section 4.4) takes into account the topography and its effect on the wind that is applied to the structure. It is 1.0 if there are no topographic effects. You can enter the desired value directly or you can click the "Calculate" button and then input various topographic parameters and have Mt calculated for you. The H, E, Lu, x and z values and the calculation of Mt are all explained in AS/NZS 1170.2 section 4.4.

231


Terrain category The terrain category affects the terrain height multiplier Mz,cat (see AS/NZS 1170.2 section 4.2). Mz,cat can be based on a single terrain category or it can be an averaged value if the terrain category changes on the upwind side of the structure. SPACE GASS allows for averaging two terrain categories in accordance with AS/NZS 1170.2 section 4.2.3. Note that the "Approach" TC is closer to the structure than the "Upwind" TC and the "TC transition distance" is the distance from the structure to the point where the terrain category changes.

Internal pressure coefficients In order to take into account openings, you can input the Cp,i pressure coefficients for maximum pressure (Pos) and maximum suction (Neg). These coefficients are then used when factoring the Cp,i=1.0 internal pressure primary load cases into the ultimate and serviceability combination load cases.

232

Portal Frame Builder Wind loads on walls Wind loads are normally applied to the columns when horizontal girts support the wall sheeting, however if the eave ties or end wall rafters are loaded instead (such as with tilt-up panels) then you can tick the "Load rafters/eaves tie" options to allow for this.

Walls as effective surfaces When SPACE GASS calculates the action combination factors Kc,e and Kc,i (see AS/NZS 1170.2 section 5.4.3) it assumes that each wall is potentially an effective surface. You can, however, specify certain walls to be not considered as an effective surface in these calculations if required (see AS/NZS 1170.2 table 5.5).

Sheeting In order to calculate friction loads, the portal frame builder needs to know the type of sheeting and its direction. You can choose between "Smooth" (no friction loads), "Ribbed" or "Corrugated".

233


Portal frame load cases This form lets you view the primary and combination load cases. The 4 internal wind pressure primary load cases (cases 4 to 7) are for the ultimate limit state and apply to a Cp,i pressure coefficient of 1.0. The 8 external wind pressure primary load cases (cases 8 to 15) are also for the ultimate limit state and are based on the actual Cp,e pressure coefficients. Along with dead load and live load, they are factored into the various combination load cases for ultimate and serviceability limit states. You can add extra combination load cases to this table, however it is sometimes easier to do this in the main SPACE GASS combination load cases datasheet once the model has been generated.

234


Portal frame design This form lets you input the steel member design parameters. The data is the same as in the steel member design input form but with some fields disabled. For more information, refer to Steel member design data. Once the model has been generated, please check the steel member design data that was generated and check that it is what you want. If not, you can edit it using the normal steel member design data input/editing methods.

235


Portal frame assumptions The following is a list of assumptions made in the current version of the portal frame builder. 1. Impact loading from wind borne debris (see AS/NZS 1170.2 section 2.5.8) is not taken into account. 2. The wind direction multiplier Md (see AS/NZS 1170.2 section 3.3) is assumed to be 0.95 for regions B, C and D, and 1.0 for all other regions and wind directions. 3. The permeable cladding reduction factor Kp (see AS/NZS 1170.2 section 5.4.5) is assumed to be 1.0. 4. Frictional drag forces (see AS/NZS 1170.2 section 5.5) are not taken into account. 5. The dynamic response factor Cdyn (see AS/NZS 1170.2 section 6) is assumed to be 1.0. 6. The wind load applied to the triangular part just below the roof in the end walls of gable buildings is not taken into account if there are no end wall rafter props. 7. The distributed live load is applied to the entire roof area, even if the roof area is greater than 200m^2. 8. The 1.4kN concentrated live load specified in AS/NZS 1170.1 (but not in conjunction with the distributed live load - see AS/NZS 1170.1 section 3.1) is not applied.

236

Datasheet Input Datasheet input You can open a datasheet by clicking the toolbar button and then selecting from the datasheet menu that appears. Alternatively, you can select one of the datasheet items from the Structure, Loads or Design menus. Datasheet input is the one of the most useful methods of entering data into SPACE GASS. All types of frame and steel design data can be input or edited via a datasheet.

For more information about operating the datasheets, refer to Using datasheets.

237


Using datasheets All datasheets have the same format, appearing in a grid format like a spreadsheet. The members datasheet is shown below.

Common datasheet operations Sorting the data on any column

Click the column heading to sort on. Further clicks cause the sorting to alternate between ascending and descending order.

Frozen key columns

Allows you to scroll the main data sideways without scrolling the key columns so that you can always see which row you are working on. In the members datasheet, the "Member" column is the key column.

Multi-row editing

Possibly one of the most useful datasheet editing tools! It allows you to edit multiple rows of data simultaneously. The procedure is as follows: 1. Select the rows to be edited by clicking the buttons at the left end of the rows, using the CTRL or SHIFT keys to highlight multiple rows (see "Selecting rows" below). 2. Move in any highlighted row to the column you want to edit. 3. Click the right mouse button. 4. Enter your data, select between replacing,

238

Datasheet Input multiplying, dividing, adding or subtracting and then click the Ok button. 5. All the highlighted rows will be updated. 6. Go back to step 2 above to edit another column.

Split screen

Move to the small black bar just to the left of the horizontal scroll arrow, click and drag it to the right to introduce and position a vertical split screen division.

Grouping

Drag a column heading button upwards to group the datasheet by that column. Drag additional buttons upwards to group in multiple levels. Right click on any of the grouped buttons and select "Clear Grouping" to cancel the grouping and put the datasheet back to normal.

Editing existing data

Move to the desired cell using the keyboard or mouse and then type in or select the desired data.

Entering new data

Move to the bottom (blank) row and then type in or select the desired data.

Uniformly distributed loads

After entering the start load magnitude for a new load in a distributed load datasheet, the finish load magnitude is automatically set to the same as the start load, saving you having to enter the load magnitude twice for uniformly

239

SPACE GASS 12 User Manual distributed loads. For existing loads this doesn't happen because the datasheet assumes that you are trying to specify a trapezoidal load. You can, however, make it happen when editing existing loads by typing into the start load cell as normal and then pressing the "F" key to "Fill" the finish load cell with the same value as the start load. Combo boxes

To edit combo box cells, either click the arrow and then make your selection or just use the keyboard arrow keys to move to the combo box cell and then type the first character of the desired selection. For example, to change a Yes/No combo box to Yes, just move to the cell and then type Y.

Selecting rows

Click the button to the left of the row to be selected. You can select multiple rows by: 1. Dragging up or down the selection buttons. 2. Selecting one row, holding down the CTRL key and then selecting additional rows. 3. Selecting one row, holding down the SHIFT key and then clicking on another selection button to select all the rows in between. Alternatively, you can click the blank button at the topleft corner of the datasheet to select all the rows.

Cutting, copying and pasting

Cut or copy selected rows from a datasheet to any other Windows program or paste from another Windows program into a datasheet.

Duplicating rows

Rows of data can be duplicated using the normal copy and paste methods, however some datasheets such as section properties contain hidden fields that would not be duplicated using these methods. For example, all the geometric data for shape builder sections is stored in hidden fields. To ensure that the hidden fields are duplicated the following procedure can be used: 1. Select the rows to be duplicated and then click the right mouse button on one of the buttons at the left end of the selected rows. 2. Select "Duplicate Rows" from the menu that appears. 3. Change the numbers of the duplicates via the "Paste Overwrite Error" form that appears so that the duplicates do not simply overwrite the selected rows. The duplicate rows will be inserted into the datasheet.

Deleting rows

Select the rows to be deleted and then press the Delete key or click the datasheet’s delete button or click the right mouse button and select Delete from the menu that appears.

240

Datasheet Input Special buttons

Special buttons on some of the datasheets allow you to quickly change specific data in the current row. For example, the special fixity buttons in the members datasheet (shown left) let you choose commonly used fixity codes without having to type them in.

Counter

A counter at the bottom-right corner of the datasheet tells you how many rows of data are in the datasheet.

Generation

The generate button on some datasheets allows you to generate a number of extra items (members, nodes, etc.). When you click the generate button you will be presented with a generation form which varies for each type of input. Most of the generation forms are selfexplanatory, however some of them employ 2nd order generation which is explained below. Note that it is often better and more convenient to use the graphical Copy tool for generating data rather than using the datasheet generate buttons.

Generation

The above node generation form allows you to generate items along two axes at once. It can also be used to generate extra series at different levels (ie. the 2nd order). Consider the following 20 node grid in the XY plane. It could have been created by inputting the coordinates for node 1 then generating four 1st order nodes (5,9,13 & 17) along a line with a node increment of 4 and X increment of 2.4, followed by three 2nd order rows of nodes with a node increment of 1 and a Y increment of -1.5. 241


Grid of generated nodes

If only 1st order generation is required, you should specify zero for the number of 2nd order items to be generated. The node generation form also has the unique ability to generate nodes along a line, arc or helix. The axis of rotation, which only applies to an arc or helix, defines the point about which the nodes will be generated. The angle increment causes the nodes to be generated at some regular angle increment. The helix length increment defines a regular increment along a parametric path at which the nodes will be generated. 2nd order generation is also employed in the member and member concentrated load datasheets. Renumbering data Any data can be renumbered by simply changing its number in a datasheet. However, be careful, because related data in other datasheets will not be automatically renumbered to match. A better way to renumber nodes, members or plates is to use the graphics renumber tool. It not only lets you renumber large groups of nodes, members and plates effortlessly, it also adjusts all of the restraints, constraints, loads, and design data automatically to allow for the new numbering sequence (see also Renumber). A convenient way to quickly move around and edit numeric cells in a datasheet is to use the keyboard arrow keys to move to the desired cell, type the new data, then use the keyboard arrow keys to move to the next cell. You do not have to press ENTER to accept the new data. ! IMPORTANT NOTE ! When you use a datasheet to renumber items, none of the other data which may reference the renumbered items is adjusted. You must do this yourself or use the renumber tool instead (as explained above). See also Analysis data.

242

Datasheet Input See also Steel member design data. See also Steel connection design data.

243

Graphical Input Graphical overview Inputting and editing your model using graphical methods is one of the most useful and intuitive input methods. You can see exactly what is in your model and you can see the changes as you make them. Nodes, members and plates can simply be drawn on the screen, and there are numerous tools for copying, renumbering, stretching, moving, generating loads and otherwise manipulating your model. The renderer window (shown below) is the default user interface for SPACE GASS, however the traditional graphics window (for those of you who prefer the older system) is also available. Because the renderer window has superior graphics and tools compared to the traditional system there is generally need to use the traditional user interface at all.

245


The renderer The SPACE GASS renderer is now the recommended tool for all of your input, analysis, design and display tools. Of course you can still edit your model in the traditional graphics window, however the editing tools in the renderer are generally more advanced and offer additional features over the traditional editing tools. All of the data is shared between the renderer and the traditional graphics window and so you can make changes in either one and then see your model updated in the other one as soon as it gets focus. The renderer user interface is the one that starts by default, however you can also open it by clicking the

button in the traditional graphics window.

Rendering mode When in the renderer you can switch between wireframe, outline and rendered views of your model by clicking the render mode selection button.

246

Graphical Input Zoom, pan, rotate You can zoom, pan or rotate your model via the mouse scrollwheel or by dragging it around using the left or right mouse buttons as shown below.

Zoom by rotating the mousewheel or by holding down the mousewheel while moving the mouse or by pressing the keyboard Up/Down arrow keys. If you find that zooming doesn’t work, click on the graphics area before trying again. Pan by holding down the right mouse button while moving the mouse. Rotate by holding down the left mouse button while moving the mouse. You can also drag the view selector (shown below) or click on one of its faces, edges or corners.

The view selector An alternative to rotating the model by dragging it around directly is to drag the view selector around. You can also click one of the view selector faces, edges or corners to go straight to a specific viewpoint. If you click on the small square attached to the front face it will take you to the 30,10 viewpoint. Note that you can also right-click one of the view selector faces to change the working plane (or press X, Y or Z while you are working).

Node, member and plate property panels The property panels operate in two slightly different modes as described below. Mode 1 - When you double-click on a node, member or plate in the model, the appropriate property panel opens and you can make changes and then click the Ok button at the bottom of the panel to confirm the changes. Alternatively, if you make some changes in a property panel and then simply click on a another node, member or plate in your model, the previous changes will be confirmed and the newly selected item's data will appear in the property panel.

247

SPACE GASS 12 User Manual Mode 2 - If you select one or more nodes, members or plates and then right-click and select "View/Edit Properties (Form)" from the menu that appears, the appropriate panel will open with the combined data for all of the selected items. When in this mode, you cannot select other nodes, members or plates until you have clicked the Ok or Cancel buttons at the bottom of the panel. Blank fields indicate that the data is different for the selected items. Be careful with blank fields because if you enter data into one of them then all of the selected items will get that data.

Single selection

248

Multiple selection

Graphical Input

Section and material property panels The section and material property panels are located by default on the right hand side of the renderer and are usually closed unless you have them pinned open. To open them simply hover over the tab.

249


You can open the property panels to view the section and material properties and color match them to the members in your model, or you can click a particular section or material in the panel to have all the matching members in your model selected.

Controlling property panels Property panels can be pinned open by clicking the button at the top of the panel so that it changes to . This means that it will stay open, even if not being used. If you click it again, it changes to , indicating that the panel is not pinned and will close when not required. If you want to close a panel manually then just click

.


250

Graphical Input

Drawing in the renderer Once you are in a tool that involves drawing a line or vector, to begin drawing you must position your cursor at the start of the line, click the left mouse button, move the cursor to the other end of the line and then click the left mouse button again. The line is dragged around with the cursor as you position the second point. The end of the first line then becomes the start of the next line and the process continues for subsequent lines until you press Esc or click the right mouse button (right-click) to end the sequence. There are a number of working plane, attachment, alignment and snap tools available to help you position points exactly where you want them while drawing or selecting points. These are explained as follows.

251


Working plane tool At any time while drawing lines or just generally moving the mouse cursor, you can see its coordinates displayed in the bottom right-hand corner of the renderer. Depending on the current working plane, you will notice that only two of the coordinates change as you move the mouse and the third one is held constant. You can change the working plane by pressing the X, Y or Z keys or by right-clicking one of the view selector faces or by clicking the working plane button

in the bottom toolbar.

Note that whenever you graphically select a point or a node, the working plane moves to the plane of that point or node. If you have a grid displayed (see below), it is drawn in the current working plane.

Attachment and alignment methods The following discussion applies to all tools that involve selecting points or drawing vectors, such as when drawing nodes, members or plates, moving, stretching, copying, extending, connecting or even when adding dimensions. During these operations there are a number of aligning, snapping and attachment tools that can help. To attach to a node (or the end of a member or the vertex of a plate), just move close to the node until it changes color. This indicates that you are close enough, and you can then click the left mouse button to attach to it. To attach to an intermediate point on a member, just move close to the member until it changes color. You can then move along the member to find its mid-point, third points, quarter points or fifth points, each of which will show up as a different colored dot with a label next to it. You can then click to attach to the desired point. Note that if you wish to position a point close to a node or member without attaching to it, you can hold down the C key to temporarily turn off the attachment feature.

252

Graphical Input If you are drawing the second end of a line then "Perpendicular" and "Orthogonal" attachment points will also be highlighted on the member if applicable.

You can even align your point with an orthogonal line extending from a node or a member's midpoint. In order to do this you must first briefly hover over the node or member until you hear a faint pop sound that indicates that you have "locked on" to it. You can then move away and a dotted line will extend from the "locked on" node or member to your point, allowing you to line up with it exactly. Note that you can temporarily turn off alignment with locked on nodes or members by holding down the A key while you are working. You can also change the "locked on" delay via the "Lock delay" setting in the Attachment and alignment methods Preferences form in the Settings menu (see below).

Similarly, you can align your point with any of the "locked on" member's three local axes as shown below.

253


You can even use it to draw a new member that is aligned with an existing member by "locking on" to the existing member and then drawing in line with it.

When aligning with a locked on node or member, you can position your point an exact distance from the locked on item by simply typing the distance rather than having to click the point with your mouse.

254

Graphical Input When drawing a line, if it is close to being aligned with one of the three global axes then it will snap to that axis. You can then either click the point with your mouse or you can just type the length of your line.

Snap tool The renderer also has a snap tool which can be turned on or off via the snap button bottom of the side toolbar or by pressing the S key.

in the

Positioning points using the keyboard In addition to being able to type a length when you are locked on to an item or aligned with a global axis as described above, you can also type an X,Y,Z coordinate to position your point if you are not locked on to an item or aligned with an axis. Coordinates can be entered as absolute or relative and in cartesian or polar coordinates. Examples of each of these are as follows:

255


Type Alignment vector length Drawn line length

Absolute cartesian Relative cartesian Absolute polar Relative polar

Situation Locked to a node or member Aligned with a global axis Not locked or aligned Not locked or aligned Not locked or aligned Not locked or aligned

Format Length

Example 10.2

Length

6.75

X,Y,Z

1.2,2.4,0.9

@X,Y,Z

@0,0,6.35

Length
6.5<45<0

@Length
For more information, refer to Using the keyboard to position points.

Selection methods You can select nodes, members or plates directly by clicking them with the left mouse button or you can use a selection window. If the second corner of the selection is to the right of the first then it is a "Normal" selection window in which only the nodes, members or plates that fall completely within the window are selected. Alternatively, if the second corner is to the left of the first then it is a "Crossing" selection window in which any nodes, members or plates that are within the window or which cross the boundary of the window are selected. A normal selection window is drawn as a rectangular box, whereas a crossing window is shown as a filled rectangle. The two types of selection window are shown below. In order to de-select nodes, members or plates, you can simply select them again, either by clicking directly or by using a selection window. Normal selection window

256

Graphical Input

Crossing selection window

Selecting a tool Once you have made your selection, you can get access to the various graphical tools by right-clicking and then selecting from the menu that appears. A typical member selection menu is shown below.

257


258

Graphical Input After selecting from the menu, the tool you selected may open a form or it may require you to pick extra points. For example, if you selected the "Generate Arc" tool from the above menu, the Arc tool would then require you to pick a point on the concave side of the arc so that it knows which direction to use when creating the arc. Whenever the graphical editor requires you to do something, it displays a red prompt at the bottom-left corner of the window as shown below. It is therefore a good idea to look there if you are not sure what to do next.

Grid tool A grid can be displayed as a visual aid while you are developing or viewing your model. The grid also assists in identifying the working plane, as it is always displayed in that plane. The grid can be turned on or off via the grid button pressing the G key.

in the bottom of the side toolbar or by

Note that if you change your working plane (see above) then the grid automatically moves to that new plane.

259


Restraints Node restraints can be turned on or off in the renderer using the button in the side toolbar. Restraints are shown using combinations of the following icons. Icon Restraint Example 3D fixed FFFFFF 3D pinned FFFRRR 2D fixed

FFRRRF

2D pinned FFRRRR 1D translation fixed 1D translation spring 1D rotation fixed 1D rotation spring

RFRRRR

RSRRRR

RRRRRF

RRRRRS

Shortcuts While using any of the renderer tools, various keyboard shortcuts are available that can speed things up. They are listed below. Shortcut Tab key F11 key G key S key X, Y or Z keys A key (hold down) C key (hold down)

Action Toggles all of the property panels on or off Toggles full screen mode on or off Toggles the grid on or off Toggles the snap on or off Allows you to set the working plane Temporarily disables aligning with a "locked on" node or member Temporarily disables attaching to a node or member Zooms in/out

Up/Down arrow keys Rotate Zooms in/out mousewheel Drag with left Rotates mouse button Drag with Pans

260

Graphical Input right mouse button

Customizing toolbars All of the toolbars in the renderer can be hidden/shown, moved or undocked, and buttons can be added or deleted. For more information refer to Customizing Toolbars.

Renderer settings and preferences Various renderer settings and preferences are available from the Settings menu as shown below.

In the following form: The "Alignment proximity" controls how close the mouse cursor must be to an axis aligned with a "locked on" node or member or a global axis in order to align with it. The "Cursor pickbox size" controls how close the mouse cursor must be to a node, member or plate in order to select it, lock onto it or display its infotip. The "Lock delay" controls how long the mouse cursor must be near a node or member before you lock onto it.

261


In the following form: The "Use previous attributes..." option, if ticked, means that when you draw a new node, member or plate it will have the same properties (ie. section ID, material ID, etc) as the previous item you drew or selected. The "Allow duplicates..." option lets you draw members or plates on top of existing members or plates (ie. so that they share the same nodes). The "Allow hidden nodes to be selectable" option allows you to select nodes that you can't see due to being behind other objects. The "Automatically prompt for new load case titles" option enables load case titles to be prompted for automatically each time a new load case is created. The "Anti-aliasing" option gives graphical text a smooth appearance by changing the color of pixels around the edges of the text. The "Order independent transparency (OIT)" option enables true (fully accurate) transparency for the display of transparent objects. If unticked (required by some older graphics cards) then the transparency is unsorted, resulting in some transparent objects appearing to be in front of objects that they should be behind. The "Support multiprocessor for RC beam design" option allows multiple zones to be designed/checked simultaneously during a reinforced concrete beam design. The "Use OpenGL for graphical forms" option controls the system used to display graphical objects in forms such as the shape builder, moving loads generator, steel connection design module, reinforced concrete design modules, portal frame builder, etc. If unticked then DirectX is used. Note that this setting doesn't affect the graphical system used in the main renderer window. The "Disable OpenGL shaders" option should be unticked for maximum graphical speed in the renderer. If ticked (required for some older graphics cards) then the renderer uses a slow software emulation mode to display graphical objects rather than utilizing the parallel processing power of the graphics card. This option should only be ticked when the renderer becomes unstable due to an old or incompatible graphics card being used.

262

Graphical Input The "Default deflection color" option, if ticked, means that when only one load case is displayed, deflections are shown by member color rather than load case color. If unticked or if multiple load cases are displayed then deflections are colored by load case. The "Curve quality" controls how many segments are used to display curved objects such as cylinders and the like. The "Result quality" controls how many short straight lines are used to approximate a curve when drawing deflected shapes, bending moment diagrams, etc. The "Structure line width" is the thickness of lines used to draw the structure when in wireframe or outline modes. The "Diagram line width" is the thickness of lines used to draw diagrams such as bending moment diagrams, etc. The "Maximum undo/redo steps" is the number of undo/redo steps that are remembered in the renderer. More memory is consumed if this setting is increased. The "Highlight delay" controls how long the mouse cursor must be near a node, member or plate before it becomes highlighted. Note that this setting has no effect over whether the node, member or plate is attached to when drawing new objects. The "Infotip delay" controls how long the mouse cursor must be near a node, member or plate before its infotip appears. The "Maximum load case components" is used to prevent memory overflow problems with large models that contain many load cases by limiting how many load cases can be displayed simultaneously. A "component" is considered to be a single diagram (eg. a load, a bending moment diagram, a shear force diagram, etc) on a single node, member or plate. If you experience memory problems when you try to display loads or analysis results graphically for many load cases simultaneously then you may need to lower this limit. Conversely, if your system has substantial memory and you are being restricted to an insufficient number of load cases when displaying loads or analysis results graphically then you could experiment with raising this limit. The "Rotation drag distance" is the number of pixels that you can move the mouse while the left button is held down before it will start to rotate the model. It is used to avoid the problem of the model rotating unintentionally when you are trying to select items or start a selection window. If this problem occurs then try increasing the rotation drag distance slightly. The "Rotation mode" controls how the model behaves when you rotate it with the mouse. Trackball mode lets the model rotate about all three axes, whereas Turntable mode prevents rotation about an axis normal to your computer screen. Trackball mode is a bit harder to control than Turntable. The "Rotate at" setting controls the centre of rotation when you rotate the model by dragging with the left mouse button held down.

263


The following form lets you can change the theme of the renderer via the "Skin" setting. This affects the colors and styles of all the forms, buttons and input fields. You can also separately change the colors of most the items in your model to suit your requirements.

264

Graphical Input

In the following form you can control the color and threshold of each pass or fail level when displaying steel member design results.

265


The size of the text displayed on the screen and in graphical prints can be controlled in the following form.

The "Other" menu option gives you access to some of the configuration settings normally found only in the traditional SPACE GASS window as follows:

266

Graphical Input For further information on each of these options, refer to "Folders and files", "Text formatting", "General configuration" and "Problem size limits". In particular, if you wish to change the vertical axis you should choose "Settings => Other => General Configuration".Other renderer tools

Other features and tools currently available in the renderer are as follows: Printing of your rendered or wireframe model. Exporting to other image formats such as DWG, DXF, IGES or STL. Undo/redo with unlimited steps. Shape builder. Library editor. Structure wizard. Portal frame builder. Find tool. Draw tool Copy node, member or plate properties tool. Filters tool. Move tool. Rotate tool. Copy tool. Mirror tool. Stretch tool. Scale tool. Renumber tool. Check connectivity tool. Generate arc tool. Generate bends tool. Subdivide tool. Intersect tool. Extend tool. Extrude tool. Connect tool. Remove intermediate nodes tool. Remove crossed member nodes tool. Move intermediate nodes tool. Align members tool. Generate taper/haunch tool. Reverse member direction tool. Mesh plates tool. Reverse plate direction tool. Align plate axes tool. Copy node, member or plate loads tool. Generate moving loads tool Generate area loads tool. Combination load cases editor. Manage load cases tool. Static load to mass conversion tool. Load case titles viewer. View manager tool. Measure tool. Dimension tool. Gridlines tool. 267

SPACE GASS 12 User Manual Notes tool. Query analysis and steel member design result tools.

If you have a large model with loads displayed and the renderer is operating slowly when you zoom, pan or rotate, try turning off the loads display or at least select less load cases to be displayed simultaneously.

268

Graphical Input

The traditional graphics window This is the original graphical interface for SPACE GASS that is gradually being replaced by The renderer. It is still available, however not recommended due to the more advanced tools available in the renderer graphical interface. You can open the traditional graphics window via the renderer's Window menu => Open Traditional SPACE GASS Window.

The process of inputting a frame graphically into SPACE GASS simply involves drawing lines on the screen with your mouse. Each line represents a member or the edge of a plate. Nodes are automatically attached to the ends of each member, at plate vertices and at points where members intersect. Node, member and plate numbering is performed automatically, or at your discretion. The graphics renumber facility lets you renumber nodes and/or members, and automatically adjusts all the other data that references nodes and/or members accordingly. In order to draw a line, you must position your cursor at the start of the line, click the left mouse button, move the cursor to the other end of the line and then click the left mouse button again. The line is dragged around with the cursor as you position the second point. The end of the first line then becomes the start of the next line and the process continues for subsequent lines until you press ESC or click the right mouse button (right-click) to end the sequence. If the end of a member is drawn so that it touches another member, the two members become connected. If attach is on then you only have to position a member close to another member in order to connect them. If you connect a member to an intermediate point along an existing member, the existing member is subdivided into two, and a node is automatically inserted at the intersection point.

269

SPACE GASS 12 User Manual Nodes, members and plates can be deleted, moved, copied, rotated, stretched, mirrored or subdivided. It is simply a matter of selecting a node, member or plate, or placing a window around a group of nodes, members and plates, and then performing the desired operation in accordance with the instructions following in this chapter. If you want to move a single node, you can just select it with your mouse and then drag it to its new location. You can see the members connected to the node being stretched as you move the node. You can select nodes, members or plates directly by clicking them with the left mouse button or you can use a selection window. If the second corner of the selection is to the right of the first then it is a "Normal" selection window in which only the nodes, members or plates that fall completely within the window are selected. Alternatively, if the second corner is to the left of the first then it is a "Crossing" selection window in which any nodes, members or plates that are within the window or which cross the boundary of the window are selected. A normal selection window is drawn with a solid line, whereas a crossing window is drawn with a dashed line. The two types of selection window are shown below. In order to de-select nodes, members or plates, you can simply select them again, either by clicking directly or by using a selection window. Normal selection window


270

Graphical Input

Once you have made your selection, you can get access to the various graphical tools by right-clicking and then selecting from the menu that appears. A typical member selection menu is shown below.

271


After selecting from the menu, the tool you selected may open a form or it may require you to pick extra points. For example, if you selected the "Generate Arc" tool from the above menu, the Arc tool would then require you to pick a point on the concave side of the arc so that it knows which direction to use when creating the arc. Whenever the graphical editor requires you to do something, it displays a red prompt at the bottom-left corner of the window as shown below. It is therefore a good idea to look there if you are not sure what to do next.

272

Graphical Input

Positioning points accurately in the traditional graphics window In order to input a structure graphically you have to be able to position the graphics cursor accurately. Unless you have the steady hands of a surgeon and you are an expert with the mouse, this is virtually impossible. Therefore, SPACE GASS has a number of indispensable tools that enable you to draw a structure to the nearest micron regardless of your surgical abilities. All of these tools can be accessed via the settings menu or activated, deactivated and/or configured using the graphics settings buttons across the bottom of the screen and/or the keyboard. All of these settings can be toggled without interrupting the use of most graphics tools. [Keyboard "G"] Clicking the Grid button displays a grid of dots on the screen at any user defined spacing. If the grid has been activated the grid button will appear depressed and instead of the text "Grid: Off" the button will display a message "Grid: x", where x is the spacing you defined. The grid can lie in the XY, XZ or YZ planes. See also Grid. [Keyboard "S"] The Snap facility, if turned on, activates a secondary crosshair graphics cursor which indicates the actual selection point and which moves in discrete steps rather than moving smoothly. The snap spacing can be set equal to the grid spacing or any other desired value. As with the Grid button, if you activate the Snap button and enter a spacing at the prompt the text on the button will change from "Snap: Off" to "Snap: x", where x is the spacing you defined. For example, if you set the snap spacing to 100mm the cursor will move in steps of 100mm, enabling you to draw to an accuracy of exactly 100mm. The button will indicate that snap has been set to 100mm by displaying the text "Snap: 100" (if units are set as mm). You can change the snap spacing as you move the cursor. SPACE GASS automatically senses when SNAP is not required and turns it off temporarily in such cases. See also Snap. [Keyboard "O"] The Ortho tool forces lines to be drawn either horizontally or vertically. Since structures are made up predominantly of horizontal beams and vertical columns, it is a very useful tool indeed. See also Ortho. [Keyboard "A"] The Attach facility displays an aperture circle with the graphics cursor and allows you to attach to existing members by simply picking points near them. The aperture circle indicates how close you must get to a member in order to attach to it. It is very useful for attaching new members to existing members or for locating points which are at the ends of members. See also Attach. [Keyboard "X,Y,Z and P"] The Plane facility allows you to change the current drawing plane. You will be able to select the drawing plane (choice of XY - "Z", YZ - "X" and XZ - "Y") as well as specifying an offset. An offset is the distance from a virtual plane to the specified plane, the distance being measured perpendicular to the virtual plane. For

273

SPACE GASS 12 User Manual example, selecting the XY plane with an offset of 5m will result in every node being created with coordinates of x,y,5. See also Plane. [Keyboard "C"] The Coordinates facility allows you to toggle between one of four coordinate systems. The different systems available are:    

Cartesian Cartesian-Relative Polar Polar-Relative

The text display at the bottom right corner of the screen will constantly change to reflect the position of the graphics cursor on the screen. The format of this text is governed by the coordinates system you have selected. Selecting the "Off" option switches all coordinates systems off and disables the coordinates display text. See also Coordinates. The keyboard can also be used to position points precisely. You simply type in the coordinates of the point using cartesian or polar coordinates in absolute or relative modes (depending upon the coordinates system selected). Note that there is no icon or button for this tool. You just need to type a number and the coordinates input form will appear automatically. See also Using the keyboard to position points. See also The renderer. Other tools There are also a number of other tools that are of great use when inputting data graphically. The query frame facility (see also Node properties, Member properties and Plate properties) allows you to point to a node, member or plate and obtain information about node coordinates, member end fixities, section properties, material properties, etc. You can also query analysis results and steel member design results. You can use the zoom, pan and viewpoint facilities to view the structure in different ways. Zoom allows you to zoom in on a portion of the structure and have it enlarged for a detailed inspection. Pan allows you to translate the structure in any direction on the screen. Viewpoint allows you to rotate your viewpoint to any position around the structure. There are a host of additional tools which allow you to scale the structure or diagrams to any desired value, show the rendered model, superimpose loading diagrams, displacement diagrams, bending moment diagrams, shear force diagrams, axial force diagrams, torsion diagrams, reactions, stress diagrams, envelopes and dynamic mode shapes, display steel connection drawings, show local axes, restraints, constraints, offsets, top flanges, etc. You can also set up a number of filters, each of which limits the amount of the model that you can see and work on. The contents of each filter can be based on a range of axis coordinates, node properties, member properties, load types and many other selection criteria that you can control. Filters can also be selected in the output reports so that they can be quickly customized to include exactly what you want to see. 274

Graphical Input

Searching for specific nodes, members or plates is easy with the find function. You can search for nodes, members or plates directly, or by reference to their properties. All aspects of what you see on the graphics screen can be saved as views that can be named and then recalled at any time. All filters, viewpoint, scales, zoom, pan and other settings applicable at the time the view is saved are recalled when the saved view is recalled. Many of the above mentioned procedures are identical in the renderer, however some of them are not and some renderer tools have more options available. For more information, refer to The renderer.

275


Align members It is easy to align or stack members using the render's "Align Members" tool. After selecting the members to be adjusted, right-click and select "Align members" from the menu that appears and then click another member to align them with. In the form that appears you can then choose to align the members according to their tops, bottoms or sides. Alternatively, you can stack members side by side or on top of one another using the "Stack" options.

In the before and after diagrams below, the blue beam has been adjusted to align with the red beam's top flange.

276

Graphical Input

277


Align plate axes You can use this tool to align the local axes of a number of plates. After you have drawn and meshed some plates, you will probably find that their local axes are all pointing in different directions. If they are left this way then the results will be for different axis directions and they will be difficult to compare. It will also be difficult to produce meaningful contour diagrams if the plate axes are not aligned. After selecting the plates to be aligned, right-click and select "Align Plate Axes" from the menu that appears. You should then click a plate that the selected plates are to be aligned with. Options include allowing plates to be reversed (ie. the direction of their local z-axes are reversed), letting plates that are currently aligned with a direction node or axis to be realigned, and adjusting pressure or thermal gradient loads for reversed plates.

278

Graphical Input

Arc generation The Arc generation tool lets you apply an arc to any member by adding intermediate nodes with any desired radius and arc plane. After selecting the members to be converted to an arc, right-click and select "Generate Arc" from the menu that appears. You should then pick any point on the concave side of the member so that the tool knows which way to bend the arc. If you have selected multiple members connected end-to-end and the "Generate continuous arc over multiple connected members" option is ticked then the Arc tool will try to generate a continuous arc that encompasses all of the connected members. This is particularly handy if you have already generated an arc and then wish to re-select it and change its radius. With this option unticked, a separate arc will be generated for each selected member.

279


Area loads One-way or two-way area loads can be generated by specifying a pressure that is applied to a roof or a floor or any other set of members that can form closed or open polygons. The pressure loads are converted to member distributed forces calculated from the contributing area of each member. You can select many members that form multiple open or closed areas and the area loading tool will process them all at once.

Two-way loads require closed areas formed by three or more perimeter members and the generated member loads are based on the load surface spanning in two directions, generally resulting in a mixture of uniform, triangular and trapezoidal loads. One-way loads don't require closed areas and the generated loads are based on the load surface spanning in just one direction, resulting in uniformly distributed loads if the supporting members are parallel, or trapezoidal if the supporting members are not parallel. After selecting the desired members to be loaded, right-click and then select "Generate Area Loads" from the menu that appears.

280

Graphical Input

281

SPACE GASS 12 User Manual For one-way area loads, if you click the "View Dummy Members" button in the one-way area loading form shown below, you can visually see the dummy members that effectively "close" the open polygons on which the one-way loads are based. Of course, the "dummy" members don't exist and don't attract any load. "Projected" areas results in the loads being based on the projected areas normal to the load direction, whereas "Actual" areas cause the generated loads to be based on the actual areas regardless of the load direction. The load direction can be parallel to one of the global axes or along any vector that you specify. You can select the load direction vector graphically by clicking the "Select Vector" button. If the "Generate loads normal to area in general load direction" option is ticked then the pressure is applied in the general load direction that you have specified, but normal to each polygon. This is handy if you have a pitched roof and you want to apply a generally vertical wind load that is normal to the roof on both sides of the ridge. The "Generate uniformly distributed forces only" option forces the pressure applied to a polygon to be applied uniformly to each member rather than as triangular or trapezoidal loads. The "Check for crossing members" option checks for members that cross over each other which could result in areas that overlap. This check should normally be left on. If the area loader generates loads on members that already contain loads in the same load case or if it generates multiple overlapping loads on the same member then the "Merge loads with matching start and finish positions" option will try to merge the loads rather than having two sets of loads with different sub-load numbers. This makes it easier to see the loads when they are viewed graphically. If this option is turned off then when identical loads are generated on a single member it might be difficult to differentiate between them when they are viewed graphically. The "Ignore member offsets when calculating areas" option treats the members as if they have no offsets and could result in slightly inaccurate results if the member offsets affect the shape or size of the area. It should only be ticked if the area loader is unable to find the desired areas due to member offsets.

282

Graphical Input

Attach This tool is only available in the traditional graphics window. The renderer has other attachment tools that replicate the function of this Attach tool. The attach tool lets you attach nodes, members, plates and reference points to existing nodes, members or plates without having to position the cursor exactly on them. You can change the attach setting by clicking on the toolbar button or selecting "Attach Mode" from the Settings menu or pressing "SHIFT+CTRL+A" on the keyboard (or just "A" if a graphics command is active). If ATTACH is on (as indicated on the toggle button above), the program displays an aperture circle with the graphics cursor and allows you to attach to existing nodes members when you pick points near them. The aperture circle indicates how close you must get to a node, member or plate in order to attach to it. The point of attachment depends on the ATTACH setting.

The settings that may be displayed on the attach button are: Off: Middle/End: Nearest/End:

Function is deactivated. Attaches to the middle or the end, whichever is closest. Attaches to the nearest point or, if an end falls 283


n%/End:

Middle: Nearest: Orthogonal: Perpendicular:

within the aperture circle, attaches to the end. Attaches to a point at the nearest n% increment along the member, or the end, whichever is closest. Attaches to the middle. Attaches to the nearest point. Attaches to a point that makes the line being drawn exactly horizontal or vertical. Attaches to a point that makes the line being drawn perpendicular to the member being attached to.

For example, if you draw a new member and wish to attach it to the end of an existing member, you can simply set ATTACH to "MIDDLE/END" and then locate the start of the new member near the end of the existing member. The two members will be automatically connected with a common node at the intersection point. To connect a member to the mid point of another member ensure that ATTACH is set to "MIDDLE" and then simply position the end of the first member to within the aperture circle radius of the second member. The second member is automatically broken into two and a node inserted at the intersection point.

The attach setting is only used if the aperture circle touches a node, member or plate.

284

Graphical Input

Attachment and alignment methods The following discussion applies to all tools that involve selecting points or drawing vectors, such as when drawing nodes, members or plates, moving, stretching, copying, extending, connecting or even when adding dimensions. During these operations there are a number of aligning, snapping and attachment tools that can help. To attach to a node (or the end of a member or the vertex of a plate), just move close to the node until it changes color. This indicates that you are close enough, and you can then click the left mouse button to attach to it. To attach to an intermediate point on a member, just move close to the member until it changes color. You can then move along the member to find its mid-point, third points, quarter points or fifth points, each of which will show up as a different colored dot with a label next to it. You can then click to attach to the desired point. Note that if you wish to position a point close to a node or member without attaching to it, you can hold down the C key to temporarily turn off the attachment feature.

If you are drawing the second end of a line then "Perpendicular" and "Orthogonal" attachment points will also be highlighted on the member if applicable.

You can even align your point with an orthogonal line extending from a node or a member's midpoint. In order to do this you must first briefly hover over the node or member until you hear a faint pop sound that indicates that you have "locked on" to it. You can then move away

285

SPACE GASS 12 User Manual and a dotted line will extend from the "locked on" node or member to your point, allowing you to line up with it exactly. Note that you can temporarily turn off alignment with locked on nodes or members by holding down the A key while you are working. You can also change the "locked on" delay via the "Lock delay" setting in the Attachment and alignment methods Preferences form in the renderer's Settings menu.

Similarly, you can align your point with any of the "locked on" member's three local axes as shown below.

You can even use it to draw a new member that is aligned with an existing member by "locking on" to the existing member and then drawing in line with it.

286

Graphical Input

When aligning with a locked on node or member, you can position your point an exact distance from the locked on item by simply typing the distance rather than having to click the point with your mouse.

When drawing a line, if it is close to being aligned with one of the three global axes then it will snap to that axis. You can then either click the point with your mouse or you can just type the length of your line.

287

SPACE GASS 12 User Manual For information about the grid, snap and working plane tools in the renderer, refer to Grid, Snap and Plane. For more information about using the keyboard to position points, refer to Using the keyboard to position points. For more information about operating the other tools in the renderer, refer to The renderer.

288

Graphical Input

Bends generation This tool in the renderer allows you to generate bends of any radius between members that are currently connected to each other.

After selecting the members to be adjusted, right-click and select "Generate Bends" from the menu that appears. Each bend is approximated by a series of straight line segments and you can specify the number of segments per 90 degrees in the form shown below. You can also specify a threshold angle to stop bends being generated between members that are close to being aligned in a straight line.

Note that a bend will not be generated between connected members if the angle is less than the threshold angle, if the bend radius is too large or if there are more than two members or a plate connected to the intersection node.

289


Combination load cases Combination load cases combine existing load cases to allow analysis of a structure with the interaction of different loads. Combination load cases are given a load case number the same as any other load case. You can open the combination load cases grid by clicking the shown below.

button in the top toolbar as

Existing combination load cases can be edited by typing into any cell. New combination load cases can be added by typing into the blank line near the top of the grid.

By hovering over a column heading or a cell in any row, information about the load case will be displayed including its title (if one exists).

The title for any combination load case can be directly input or edited via the "Title" column in the datasheet, plus if you right-click on a column heading you can input or edit a primary or combination load case's title or notes.

290

Graphical Input

If you have a large number of columns and you don't want to repeatedly scroll sideways to get to the cells you need, you can condense the grid for any combination load case by simply clicking the arrow to the left of the combination load case you are interested in. You can then condense the grid for any other row or you can revert back to the default sorting by clicking the * button near the top-left corner of the grid.

When creating combination load cases, if the columns you need are not included in the grid, you can add them by clicking the "Add Columns" button near the top-right corner of the grid and then listing the extra load cases required.

291

SPACE GASS 12 User Manual See also Datasheet Input.

292

Graphical Input

Connect The Connect tool allows you to connect members that cross each other within a specified distance but which are not currently connected. After selecting the members to be connected, right-click and select "Connect" from the menu that appears. Members that cross each other within the tolerance you specify in the following form will be connected.

After using the Connect tool, if you want to check that the members are properly connected, you can use the "Connectivity" tool. See also Intersect.

293


Connectivity check The Connectivity tool lets you see graphically what is connected to a particular node, member or plate. It is a very handy tool if you are not sure if certain nodes. members or plates are properly connected. For example, it will quickly tell you if a member simply passes over a node or if it is properly connected to it. Right-click on a single node, member or plate and then select "Connectivity Check" from the menu that appears. The nodes, members and plates that are connected to the selected item are then highlighted graphically. You can then proceed to click on any other nodes, members or plates in your model to check their connectivity.

294

Graphical Input

Coordinates The Coordinates tool shows the position of the mouse cursor while you are drawing lines or selecting points. The renderer version In the renderer, the coordinates tool is for display purposes only and cannot be changed to relative or polar. It appears in the bottom right-hand corner of the renderer as shown below.

The traditional graphics window version This tool not only allows you to view the mouse coordinates, but you can also cycle between cartesian and polar coordinates using absolute or relative modes.

You can change the displayed coordinates by clicking the toolbar button or selecting "Coordinates Display" from the Settings menu or pressing "SHIFT+CTRL+C" on the keyboard (or just "C" if a graphics command is active). The current COORDINATES setting is displayed on the graphics settings button (as indicated above). Choices are:

Cartesian, Cartesian-Relative, Polar, Polar-Relative, Off.

When a graphics operation is active, the actual coordinates of the graphics cursor are displayed at the bottom-right corner of the screen. If you select the second corner of a window or line and the COORDINATES setting is in a relative mode then the coordinates displayed are relative to the first point of the window or line. Relative coordinates are the same as absolute coordinates when you select a single point or the start of a line.

The COORDINATES setting does not restrict your choice of Cartesian, polar, absolute and relative modes when inputting points from the keyboard. For example, you can enter a point from the keyboard using polar coordinates even if the COORDINATES display is set to Cartesian coordinates (see also Using the keyboard to position points).

295


Copy The Copy tool allows you to copy members or plates in any straight line direction, or around an arc or helix. This is very useful for structures such as trusses where you can draw just the first panel and then make copies of it to build up the complete structure. After selecting the members or plates to be copied, right-click and select "Copy to Locations", "Copy along Line", "Copy along Arc" or "Copy along Helix" from the menu that appears. If copying to locations, you should then pick a reference point on the items being copied, fill out the form that appears below and then simply click wherever you want to the selected items to be copied to. You can then continue to click additional locations to have the selected items copied there too.

If copying along a line, you should then pick two points that represent the ends of a vector through which the items are to be copied.

296

Graphical Input

If copying along an arc, you should then pick the center of the arc and then fill out the form that appears below.

If copying along a helix, you should then pick the center of the helix arc and then fill out the form that appears below.

Don't forget that when drawing in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

297


After copying some members or plates, if you are not sure that they are properly connected to other nodes, members or plates, you can use the "Connectivity" tool.

298

Graphical Input

Copy member loads The Copy Node Loads tool lets you copy loads from a loaded member to a selection of destination members. The renderer version After selecting the destination members, right-click and select "Copy Member Loads" from the menu that appears. You should then click the source member, followed by specifying the load cases that the loads are to be copied from in the form shown below. If you tick the "Delete and replace loads on destination members for the specified load cases" option then all pre-existing member loads on the selected destination members contained within the selected load cases will be deleted first. If it is unticked then the loads being copied will be added to the pre-existing loads.

The traditional graphics window version The procedure is the reverse of the renderer procedure above. After selecting the source member, right-click and select "Copy Member Loads" from the menu that appears. You should then select the destination members, right-click and then select Ok to have the loads copied. All pre-existing member loads on the selected destination members contained within the selected load cases will be deleted and replaced by the copied loads.

299


Copy member properties The Copy Member Properties tool lets you copy the member, section, material and offset properties of a member to a selection of destination members. The renderer version After selecting the destination members, right-click and select "Copy Member Properties" from the menu that appears. You should then click the source member, after which its properties are copied to the destination members. The traditional graphics window version The procedure is the reverse of the renderer procedure above. After selecting the source member, right-click and select "Copy Member Properties" from the menu that appears. You should then select the destination members, right-click and then select Ok to have the properties copied.

300

Graphical Input

Copy node loads The Copy Node Loads tool lets you copy loads, prescribed displacements and lumped masses from a loaded node to a selection of destination nodes. The renderer version After selecting the destination nodes, right-click and select "Copy Node Loads" from the menu that appears. You should then click the source node, followed by specifying the load cases that the loads are to be copied from in the form shown below. If you tick the "Delete and replace loads on destination nodes for the specified load cases" option then all pre-existing node loads, prescribed displacements and lumped masses on the selected destination nodes contained within the selected load cases will be deleted first. If it is unticked then the loads being copied will be added to the pre-existing loads.

The traditional graphics window version The procedure is the reverse of the renderer procedure above. After selecting the source node, right-click and select "Copy Node Loads" from the menu that appears. You should then select the destination nodes, right-click and then select Ok to have the loads copied. All pre-existing node loads, prescribed displacements and lumped masses on the selected destination nodes contained within the selected load cases will be deleted and replaced by the copied loads.

301


Copy node properties The Copy Node Properties tool lets you copy the restraint and master-slave constraint properties of a node to a selection of destination nodes. The renderer version After selecting the destination nodes, right-click and select "Copy Node Properties" from the menu that appears. You should then click the source node, after which its properties are copied to the destination nodes. The traditional graphics window version The procedure is the reverse of the renderer procedure above. After selecting the source node, right-click and select "Copy Node Properties" from the menu that appears. You should then select the destination nodes, right-click and then select Ok to have the properties copied.

302

Graphical Input

Copy plate loads The Copy Plate Loads tool lets you copy loads from a loaded plate to a selection of destination plates. The renderer version After selecting the destination plates, right-click and select "Copy Plate Loads" from the menu that appears. You should then click the source plate, followed by specifying the load cases that the loads are to be copied from in the form shown below. If you tick the "Delete and replace loads on destination plates for the specified load cases" option then all pre-existing plate loads on the selected destination plates contained within the selected load cases will be deleted first. If it is unticked then the loads being copied will be added to the pre-existing loads.

The traditional graphics window version The procedure is the reverse of the renderer procedure above. After selecting the source plate, right-click and select "Copy Plate Loads" from the menu that appears. You should then select the destination plates, right-click and then select Ok to have the loads copied. All pre-existing plate loads on the selected destination plates contained within the selected load cases will be deleted and replaced by the copied loads.

303


Copy plate properties The Copy Plate Properties tool lets you copy the plate, material and offset properties of a plate to a selection of destination plates. The renderer version After selecting the destination plates, right-click and select "Copy Plate Properties" from the menu that appears. You should then click the source plate, after which its properties are copied to the destination plates. The traditional graphics window version The procedure is the reverse of the renderer procedure above. After selecting the source plate, right-click and select "Copy Plate Properties" from the menu that appears. You should then select the destination plates, right-click and then select Ok to have the properties copied.

304

Graphical Input

Delete The Delete tool allows you to delete any or all of the structure. The items to be deleted are first highlighted so that you can verify them before they are actually removed. Nodes connected to deleted members or plates are also deleted unless they are connected to other members or plates that still exist. After selecting the nodes, members or plates to be deleted, press the Delete key or right-click and select "Delete" from the menu that appears. The selected items are then deleted. .

305


Draw The Draw tool allows you to draw new nodes, members or plates and attach them to existing nodes, members or plates. Nodes are automatically generated at the ends of each member or plate vertex. If a member or plate is attached to the intermediate point of an existing member, the existing member is subdivided into two and a node is automatically inserted at the intersection point. When in drawing mode you can control the numbering of new nodes, members and plates being drawn by pressing the keyboard N, M or P keys and then specifying the number of the next node, member or plate to be drawn. Alternatively, you can simply let SPACE GASS find the next available node, member or plate. You can easily renumber any nodes, members or plates later using the Renumber tool. For members, the procedure is as follows. 1. Click the

(renderer) or

(traditional graphics window) toolbar button.

Note that you can switch to drawing plates by pressing the T key to switch to drawing triangular plates or the Q key to switch to drawing quadrilateral plates. You can switch back to drawing members by pressing the M key.

2. Pick the start of a new member. This can be a new point not connected to existing members or plates, or it can be an existing member or plate end point or member intermediate point. Don't forget that when drawing in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

3. Pick the end of the new member. Again, this can be a new point or a point on an existing member or plate. 4. If you wish to draw another member that extends from the end of the member just drawn then pick another end point. You can keep picking end points for additional members. 5. Press ESC or the right mouse button to end the operation. 6. Return to step 1 above to draw another member, or press ESC or the right mouse button to exit from the tool.

Be careful when subdividing or connecting to intermediate points on members that have local Y or Z member offsets. Because local offsets are calculated relative to a straight line joining the member’s end nodes, they will change direction if you add intermediate

306

Graphical Input nodes. It is therefore recommended that you should always convert any local Y or Z member offsets to global before adding intermediate nodes.

If you wish to draw multiple members between the same two nodes, you will need to first activate the "Allow duplicates when drawing new members" option in the "General configuration" item of the Config menu. For plates, the procedure is as follows. 1. Click the or (renderer) or (traditional graphics window) toolbar button and then select between drawing triangular or quadrilateral plates. Note that you can switch between drawing triangular or quadrilateral plates while drawing by pressing the T key to switch to drawing triangular plates or the Q key to switch to drawing quadrilateral plates. You can also switch to drawing members by pressing the M key. Note also that while in quadrilateral plate drawing mode, you can draw triangular plates by simply double-clicking the 4th node.

2. Pick the start of a new plate. This can be a new point not connected to existing members or plates, or it can be an existing member or plate end point or member intermediate point. Don't forget that when drawing in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

3. Pick the next vertex of the new plate. Again, this can be a new point or a point on an existing member or plate. 4. Pick the third and fourth (if a quadrilateral plate) vertices of the new plate. 5. If you wish to draw another plate that extends from the end of the plate just drawn then pick another point. You can keep picking points for additional plates. 6. Press ESC or the right mouse button to end the operation. 7. Return to step 1 above to draw another plate, or press ESC or the right mouse button to exit from the tool.

You can draw triangular plates while in quadrilateral plate drawing mode by doubleclicking the 4th node of quadrilateral plates.

307


While drawing, you can switch between drawing members or plates by pressing the M key to switch to drawing members, the T key to switch to drawing triangular plates or the Q key to switch to drawing quadrilateral plates.

Plates must be flat (ie. all vertices in the same plane).

After drawing some members or plates, if you are not sure that they are properly connected to other nodes, members or plates, you can use the "Connectivity" tool.

308

Graphical Input

Extend Members can be extended or shortened using this tool in the renderer. After selecting the members to be extended or shortened, right-click and select "Extend" from the menu that appears. You must then select a reference point graphically. This just allows you to control which ends of the members will move and which ends will stay in place. The form shown below then appears. The "Mode" option lets you choose between specifying a new length or specifying an extension or reduction. The "Move" option lets you control which ends of the members will be moved. In the "New length" or "Extension" field at the bottom of the form, you can specify the new length or extension (or shortening) as an absolute value or as a percentage of the original member length.

309


Extrude The extrude tool lets you extrude multiple members in any direction. It is extremely handy for extruding a set of columns from the ground or from an existing floor of a multi-storey building. After selecting some nodes to extrude from, right-click and select "Extrude" from the menu that appears. The nodes you select do not have to be coplanar. You should then pick two points that represent the ends of a vector along which the members will be extruded. Note that the position of the vector is unimportant, as it is just the length and direction of the vector that matters. Don't forget that when drawing the vector, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points". The extrude form then appears, allowing you to set the node increment if desired, otherwise just leave it at 0 to use the next available node numbers. The node increment can be useful if you have a regular node numbering scheme for each floor of a multi-storey building.

The members are then extruded from the selected nodes in accordance with the length and direction of the extrude vector.

310

Graphical Input When extruding members from the ground, it can be useful to set up some Gridlines and then use the Draw Nodes tool to create nodes at the gridline intersections from which columns are to be extruded. You can then select all the nodes just created and extrude columns from them.

311


Filters The filter tool allows you to restrict the amount of data that is displayed in the graphics display area or in output reports. You can use it to restrict the display to specific nodes, node types, members, member types, plates, plate types, section properties, material properties, load types, buckling modes, steel members, steel connections, axis limits or any combinations of these. To create a filter from nodes, members or plates selected graphically Select some nodes, members or plates graphically by picking them or by using the "Find" tool and then select "Create Filter" from the floating menu, after which the following form appears.

To save the current selection as a filter, just click the combo box in the above form, select a filter number and then type in the filter’s name. You can overwrite previously saved filters or you can select and name an unused filter. An alternative method of creating a filter from nodes, members or plates selected graphically is to use the "Select" buttons in the main filters form as explained below. To create or edit filters Click the

312

toolbar button or select "Filters" from the View menu or the floating menu.

Graphical Input

For each filter you can select one or more check boxes and then specify the corresponding items to be included in the filter. For example, if you specify a member list of 1,2-6,9,10 and a section property list of 2,3, the filter will include only those members in the specified list that use section properties 2 or 3. The more check boxes you enable and corresponding items you specify, the more you limit the nodes, members or plates that are included in the filter. You can define up to 200 different filters and scroll between them in the form by changing the "Filter" numeric field.

The Include/Exclude buttons simply reverse the effect of the items in the filter line. For example, if you specify a node list of 2-5,9,13 and select "Include" then those nodes will be included in the filter. However, if you select "Exclude" then all the nodes except 2-5,9 and 13 will be included in the filter.

You can use the "Select" buttons in the "Nodes", "Members" and "Plates" lines to graphically select or edit node, member and plate lists rather than having to type them in manually. You can also use the "Select" buttons to graphically add to or modify filters that were previously defined using other than node, member or plate lists. Filters can also be based on lists of steel design members or connections, or steel member design results. The "X-axis", "Y-axis", and "Z-axis" fields allow you to specify minimum and maximum limits for one or more axis directions. You can enter ranges into the fields manually or select them graphically by clicking their "Select" button. Any parts of the frame which fall outside of these limits are excluded from the filter. The "Make filtered out members and plates" selection allows you to completely hide any members or plates that are not included in the active filter or show them transparent. You can also change the color and transparency of the filtered out objects. To select and activate a filter Click the "Filters" toolbar combo box

and make your selection.

Scrolling through the filters can be most conveniently done using the keyboard Ctrl+Page keys as described in Shortcuts. To import or export filters Click the Import or Export button and then choose the type of file to import from or export to. You can import from MS-Excel or MS-Access. You can export to MS-Excel, MS-Access, MSWord, or a text, PDF, RTF, HTML or CSV file. The import/export tools are very handy if you want to transfer the filters from one job to another, or if you have generated them in a program such as MS-Excel and then want to bring them into your job. Copy and paste You can use the copy and paste buttons to transfer your filters from one job to another.

313


Find You can use the Find tool to quickly locate nodes, members or plates in your model by clicking the

button in the top toolbar.

The renderer version

Before clicking Ok, if you want to see which items would be found you can click the button to have them listed as shown below. You can then click the button if you want to copy a list of the found items into the clipboard, ready for pasting into another part of SPACE GASS or another program.

You can also find all the members or plates with a particular section or material by clicking the desired section or material in its property panel and then having all the matching members or plates selected.

314

Graphical Input

The traditional graphics window version

You can find nodes, members or plates by listing their numbers directly or by specifying their properties or the nodes/members/plates to which they are connected. Only those nodes, members or plates that satisfy all of the find criteria in the form are found.

315

SPACE GASS 12 User Manual When a node, member or plate is found, it is highlighted graphically the same as if you had selected it by picking it with the mouse. You can use the highlighting simply as a visual reference to see where the found nodes, members or plates are in your structure, or you can click a toolbar button or click the right mouse button and choose from the floating menu that appears to perform an operation on the selected nodes, members or plates. You can cancel the highlighting by pressing the keyboard ESC key or by selecting "Cancel" from the floating menu. If you are searching for members of a certain section or material, you can also just click the desired section or material in the properties panel of the renderer to highlight all the members in your model that use it. After the Find tool highlights the nodes, members or plates you are searching for, you can perform many graphics operations on them by right-clicking and then selecting from the menu that appears.

316

Graphical Input

Grid A grid can be displayed as a visual aid while you are developing or viewing your model. The grid also assists in identifying the working plane, as it is always displayed in that plane. The renderer version The Grid tool can be turned on or off via the grid button or by pressing the G key.

in the bottom of the side toolbar

Note that if you change your working plane then the grid automatically moves to that new plane.

For more information about the attachment, alignment, snap and working plane tools in the renderer, refer to Attachment and alignment methods, Snap and Plane.

The traditional graphics window version You can display a rectangular grid in the XY, XZ or YZ global planes by clicking the toolbar or selecting "Grid" from the Settings menu or pressing "SHIFT+CTRL+G" on the keyboard (or just "G" if a graphics command is active).

317

SPACE GASS 12 User Manual It is a useful visual reference as you move the cursor around the screen. The GRID can be set to any desired size provided it is not too fine or too coarse to be properly displayed. The GRID setting uses the same system of units as the structure being displayed. It can be toggled on or off by again clicking the "Grid" toolbar button or re-selecting the "Grid" menu item. The current GRID setting is displayed on the graphics settings button (as indicated above). If you change the operating plane while a grid is displayed, the grid will not be updated until you perform an operation which refreshes the entire screen such as PAN, ZOOM, VIEWPOINT, SCALE, REDRAW, etc.

In the traditional graphics window, the grid can only be displayed in one of the global planes. It cannot be offset a distance out along one of the axes. If you are operating in a plane which is offset from the 0,0,0 global origin and your viewpoint is at an angle to the plane you are working in, do not try to use the displayed grid as a reference. It is only useful if you are operating in the same plane as the grid or if your viewpoint is perpendicular to the operating plane.

318

Graphical Input

Gridlines Gridlines can be added to your model at any stage of its development. As well as providing a visual reference, they can also be attached to when you are drawing or editing your model.

Gridlines can be created, edited or turned on or off via the button in the bottom of the side toolbar. You can simply enter the desired gridline tags, positions and elevations into the appropriate tables of the form shown below. By entering more than one line of data in the Elevations table you can have multiple sets of gridlines at different elevations.

319

SPACE GASS 12 User Manual Gridlines can also be generated by clicking "Auto Generate Gridlines" buttons via the form shown below.

320

Graphical Input

Infotips If you hover the mouse over a node, member or plate in the renderer, an infotip appears that gives useful information about the object as shown below. Infotips can be turned on or off by clicking the left hand part of the button at the bottom of the side toolbar. If the button is on but infotips don't appear when you move the mouse over the structure, click the arrow part of the button and check that the "Structure Infotips" option is ticked. Note that you can also temporarily hide infotips while you're working by holding down the I key.

See also Query analysis results.

321


Intersect The Intersect tool allows you to join two or more members and automatically insert nodes at the intersection points. It works with members that are not touching each other, and with members that cross over each other. After selecting the members to be intersected, right-click and select "Intersect Move", "Intersect Extend" or "Intersect Offset" from the menu that appears. You should then click a member that the selected members are to intersect with. If you choose "Intersect Move", the ends of the selected members will be moved to the intersection points. If you choose "Intersect Extend", new members will be added that extend from the ends of the selected members to the intersection points. If you choose "Intersect Offset", member offsets will be added that offset the ends of the selected members to the intersection points. Because the "Move ends" or "Extend ends" selection only affects members which don’t already pass through the intersection point, the selection is irrelevant for members that cross over each other.

! IMPORTANT NOTE ! Concentrated loads and distributed forces acting on a member that is subdivided as the result of an intersect operation are now automatically re-distributed onto the subdivided members, however in the traditional graphics window distributed torsion, thermal and prestress loads are not!

Be careful when intersecting with members that have local Y or Z member offsets. Because local offsets are calculated relative to a straight line joining the member’s end nodes, they will change direction if you add intermediate nodes. It is therefore recommended that you should always convert any local Y or Z member offsets to global before intersecting at an intermediate point.

After using the Intersect tool, if you want to check that the members are properly connected, you can use the "Connectivity" tool. See also Connect.

322

Graphical Input

Keyboard positioning of points

If you can’t easily position a point using the mouse, you can simply type in the desired coordinates. You can enter points in cartesian or polar coordinates, using absolute or relative modes. As soon as you start typing, the following form will appear automatically.

A point can be entered using cartesian coordinates by simply typing the X, Y and Z values separated by commas. For example, 2.3,1.2,0.5 locates a point at X=2.3, Y=1.2 and Z=0.5. If you type less than three values for a point, the missing values are assumed to be zero. For example, 2.3,0,0 could be shortened to just "2.3", or 2.3,1.2,0 could be shortened to "2.3,1.2". To locate the "0,0,0" origin very quickly, you only have to type 0. A point can be entered using polar coordinates by typing a distance, followed by a vertical angle (from the global XZ plane), followed by a horizontal angle (from the global XY plane). <’s are used to separate the values rather than commas. For example, a point 10 units from the origin with a vertical angle of 45 and a horizontal angle of 15, could be typed in as 10<45<15. To enter points in relative mode (ie. relative to the other end of a line) apply an "@" prefix to the coordinates. For example, a point which is 8 units in the X direction and 6 units in the Y direction from a previous point, could be typed in as @8,6, or @10<36.9. If you are using the renderer, you can also type a length if you are drawing a line or vector that is aligned with a global axis or an alignment vector from a node or member that you are "locked on" to. Type Alignment vector length Drawn line length Absolute cartesian Relative cartesian Absolute polar Relative polar

Situation Locked to a node or member Aligned with a global axis Not locked or aligned Not locked or aligned Not locked or aligned Not locked or aligned

Format Length

Example 10.2

Length

6.75

X,Y,Z @X,Y,Z Length
1.2,2.4,0.9 @0,0,6.35 6.5<45<0 @10<30<0

In the traditional graphics window, if you use the keyboard to type in coordinates for a point that is within the aperture circle distance of a member, and

323

SPACE GASS 12 User Manual ATTACH is on, the point will not attach unless you make a direct hit. Any point positioned with the keyboard is kept at the exact coordinates that you type in. For information on attachment, alignment, working plane, grid and snap tools that allow you to position points accurately in the renderer, refer to Attachment and alignment, Plane, Grid, Snap and The renderer. For information on snapping and attachment tools available that allow you to position points accurately in the traditional graphics window, refer to The traditional graphics window.

324

Graphical Input

Load case titles Load case titles allow you to describe your load cases so that they can be easily identified. For each load case you can specify a short title and a longer description. You can open the load case titles datasheet by selecting "Load Case Titles" from the Loads menu and then entering data into the datasheet as explained in Load case title data.

Note that you can open a load case titles viewer from within the renderer that can be left open while you work with other tools. For more information, refer to Load case titles viewer. See also Datasheet Input.

325


Lumped masses This tool allows you to graphically apply lumped masses to nodes. Masses are always referenced to the global axes system. You must apply some lumped masses before a dynamic frequency analysis can be performed. The procedure is as follows. 1. Select the nodes you wish to load, click the right mouse button and then select "Lumped Masses" from the floating menu that appears. OR Click the toolbar button or select "Lumped Masses - Graphical" from the Loads menu, select the nodes you wish to load, click the right mouse button and then click Ok.

2. In the load case form that appears, if you are inputting new masses then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing masses then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them. You should then choose between showing the masses applied to each selected node individually (ie. one line of data for each node) or applied as a group to all the selected nodes (ie. one line of data for all the nodes). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected nodes. This can be particularly useful if you are applying the same mass to a number of nodes. If you are inputting a different mass on each node then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what masses are already applied to the nodes you have selected. If you have elected to show the masses applied to each node individually then you can also choose between showing all the selected nodes or just the ones that are loaded. If you are inputting new masses then you would probably choose to show all the selected nodes, whereas if you are editing existing masses or just viewing masses then showing just the loaded nodes may be preferable.

3. A datasheet then appears with any existing masses shown. You can add, edit or delete masses and then click the Ok button to save any changes. The operation of the 326

Graphical Input datasheet is the same as the non-graphical datasheets (see also Datasheets).

Refer to "Using datasheets" for information on how to operate the above datasheet. Note that static loads can be converted to masses using the static load to mass conversion tool in the renderer. For more information, refer to Static load to mass conversion. See also Lumped mass data.

327


Managing load cases The renderer version You can use the Manage Load Cases tool to copy, renumber or delete entire load cases by clicking the

button in the top toolbar of the renderer.

When specifying the source load case list, you can either list them directly, or you can click the button to display and select from a list of the load cases currently in the job as shown below.

328

Graphical Input The traditional graphics window version You can use the Manage Load Cases tool to copy, renumber or delete one load case at a time by clicking the

button in the traditional graphics window.

329


Master-slave constraints Master-slave constraints are incorporated into node properties. See also Property panels. See also Master-slave constraints. See also Node properties.

330

Graphical Input

Material properties Material properties are incorporated into the member and plate properties forms. See also Property panels. See also Material properties. See also Member properties. See also Plate properties.

331


Measurements and dimensions The Measurement and Dimensioning tool in the renderer lets you measure distances and angles between points that you select graphically or lengths and orientations of members. You can also add dimensions to your model. Measure Right-click on a member, on a node or on any point away from your model and then select "Measure/Dimension" in the menu that appears. Alternatively, you can select two nodes or two other points, right-click and then select "Measure/Dimension" or you can simply click the button in the toolbar at the bottom of the side toolbar. The form that appears below shows the actual distance (or member length), the projected distances and the angles between the nodes, member ends or points selected. You can then continue to click other nodes, members or points on or around your model and see the data updated in the form.

Dimension At any time while using the Measure tool, you can click the "Add Dimension' button in the form to add a dimension to your model. If the dimension is not exactly how you want it, you can experiment with the settings in the "Dimension" part of the form to adjust it as required. Dimensions can be updated or deleted by simply selecting them, right-clicking and then selecting "Edit Dimension" or "Delete" from the menu that appears. Dimensions can be turned on or off via the

332

button at the bottom of the side toolbar.

Graphical Input

Don't forget that if you want to select a point that is not on a node or a member but is lined up with one, you can simply hover over the node or member for a second until you hear the "lock on" pop sound and you can then move away and still stay lined up. This is handy if you want to add dimension lines some distance away from a point such as with the "12m" dimension in the model shown above. In this case you could click the node at the bottom of the column, hover over the apex node until it "locks on" and then move back in line with the column staying lined up with the apex node before clicking the second dimension point (see below). For more information, see Attachment and alignment methods.

333


Member concentrated loads This tool allows you to graphically apply force and moment concentrated loads to members. Member loads can be referenced to the global or local axes systems and can be positioned anywhere along the member. The procedure is as follows. 1. Select the members you wish to load, click the right mouse button and then select "Concentrated Loads" from the floating menu that appears. OR Click the toolbar button or select "Member Concentrated Loads - Graphical" from the Loads menu, select the members you wish to load, click the right mouse button and then click Ok.

2. In the load case form that appears, if you are inputting new loads then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing loads then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them. You should then choose between showing the loads applied to each selected member individually (ie. one line of data for each member) or applied as a group to all the selected members (ie. one line of data for all the members). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected members. This can be particularly useful if you are applying the same load to a number of members. If you are inputting a different load on each member then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what loads are already applied to the members you have selected. If you have elected to show the loads applied to each member individually then you can also choose between showing all the selected members or just the ones that are loaded. If you are inputting new loads then you would probably choose to show all the selected members, whereas if you are editing existing loads or just viewing loads then showing just the loaded members may be preferable.

3. A datasheet then appears with any existing loads shown. You can add, edit or delete loads and then click the Ok button to save any changes. The operation of the datasheet is the same as the non-graphical datasheets (see also Datasheets). 334

Graphical Input

Refer to "Using datasheets" for information on how to operate the above datasheet. You can apply more than one concentrated load to the same member within the same load case by specifying a different sub-load number for each different member concentrated load. See also Member concentrated load data.

335


Member distributed forces This tool allows you to graphically apply distributed forces to members. Member loads can be referenced to the global or local axes systems and can be positioned to start and finish anywhere along the member. They can be uniformly distributed or linearly varying along the member. The procedure is as follows. 1. Select the members you wish to load, click the right mouse button and then select "Distributed Forces" from the floating menu that appears. OR Click the toolbar button or select "Member Distributed Forces - Graphical" from the Loads menu, select the members you wish to load, click the right mouse button and then click Ok.


3. A datasheet then appears with any existing loads shown. You can add, edit or delete loads and then click the Ok button to save any changes. The operation of the 336

Graphical Input datasheet is the same as the non-graphical datasheets (see also Datasheets).

Refer to "Using datasheets" for information on how to operate the above datasheet. You can apply more than one distributed force to the same member within the same load case by specifying a different sub-load number for each different member distributed force. This allows you to apply "stepped" distributed forces along a member without having to resort to intermediate nodes. See also Member distributed force data.

337


Member distributed torsions This tool allows you to graphically apply distributed torsions to members. Member distributed torsion loads are always referenced to the local axes system and can be positioned to start and finish anywhere along the member. They can be uniformly distributed or linearly varying along the member. The procedure is as follows. 1. Select the members you wish to load, click the right mouse button and then select "Distributed Torsions" from the floating menu that appears. OR Select "Member Distributed Torsions - Graphical" from the Loads menu, select the members you wish to load, click the right mouse button and then click Ok.


3. A datasheet then appears with any existing loads shown. You can add, edit or delete loads and then click the Ok button to save any changes. The operation of the datasheet is the same as the non-graphical datasheets (see also Datasheets).

338

Graphical Input

Refer to "Using datasheets" for information on how to operate the above datasheet. You can apply more than one distributed torsion to the same member within the same load case by specifying a different sub-load number for each different member distributed torsion. This allows you to apply "stepped" distributed torsions along a member without having to resort to intermediate nodes. See also Member distributed torsion data.

339


Member offsets Member offsets are incorporated into member properties. See also Property panels. See also Member offsets. See also Member properties.

340

Graphical Input

Member prestress loads This tool allows you to graphically apply prestress loads to members. The procedure is as follows. 1. Select the members you wish to load, click the right mouse button and then select "Prestress Loads" from the floating menu that appears. OR Select "Member Prestress Loads - Graphical" from the Loads menu, select the members you wish to load, click the right mouse button and then click Ok.



341


Refer to "Using datasheets" for information on how to operate the above datasheet. See also Member prestress data.

342

Graphical Input

Member properties The member property forms described here are only available in the traditional graphics window. For information about the renderer's property panels, refer to Property panels or The renderer. Member properties include member type, connectivity, orientation, fixity, section properties, material properties and member offsets. Hence, selecting the graphical option for "Members", "Section properties", "Material properties" or "Member offsets" will all take you to the same member properties form. There are three modes available for editing member properties as follows. To edit or query member properties one member at a time Simply double-click on a member. Note "Edit/Query Member" in the title bar of the form that appears.

Although this mode only lets you edit the properties of one member at a time, you can simply click on any other member to display and edit its properties without exiting the command. When doing so, any changes you made to the properties of the previously displayed member are saved. You can also press the "Results" button and then click on any members to display their analysis results in a scrollable window (see also Query analysis results). To edit or query member properties for multiple members using a form Select some members graphically, click the right mouse button and then select "Properties (Form)" from the floating menu that appears. Note "Edit Member Properties" in the title bar of the form that appears.

343


Edit mode works in a similar way to edit/query mode except that you can’t select other members while the form is open. You can, however select multiple members initially and make changes to all of them simultaneously. Blank fields A blank field indicates that for the members selected, more than one value exists. If you leave such a field blank then the selected members will retain their individual values. However, if you type into a blank field then all of the selected members will receive the new value. Special buttons Shows or hides the section properties part of the member properties form.

Shows or hides the material properties part of the member properties form.

Shows or hides the member offsets part of the member properties form.

Allows you to input a section or material from a standard library.

Initiates the shape builder.

Initiates the standard shapes input. Section and material properties are different to the other items in the members form because a single section or material can be shared amongst many members. All other items of data in the members form have their own independent values for each member. Hence, as soon as you change the section or material property number, the rest of the section or material data changes to match.

344

Graphical Input

You can scroll through the sections or materials in the current job by changing the section or material number in the member properties form. All of the properties that have been defined for that section or material will be displayed. If no properties have been defined for that section or material then the name field will be blank, as will the properties fields. To edit or query member properties for multiple members using a datasheet Select some members graphically, click the right mouse button and then select "Properties (Datasheet)" from the floating menu that appears. Note that the datasheet that appears is different to the normal members datasheet because it contains extra columns for section properties, material properties and offsets.

Refer to "Using datasheets" for information on how to operate the above datasheet.

You can view member hinges, member offsets or section properties graphically by depressing the "View member hinges", "View member offsets" or "View rendered model" toggle buttons in the side toolbar.

If you change any member properties that affect the structure’s geometry, you may not be able to select some nodes or members until after a redraw. This is due to their displayed position becoming out-of-date. The "Regen" check box allows you to order an automatic redraw after you exit the node properties form. See also Members. See also Section properties. See also Material properties. See also Member offsets. See also Floating mouse menus. See also View node / member / plate properties.

345


Mesh The Mesh tool allows you to select one or more plates and then mesh them into smaller elements. You can also subdivide quadrilateral plates into triangles. Unlike frame elements, plate elements (like all finite elements) are not exact and hence the accuracy of the analysis increases as the number of plate elements is increased. It is therefore important that your model is properly meshed. The normal procedure for generating a well meshed model is to draw large plates that define the overall walls, slabs and other components and then use the mesh tool to subdivide the large plates into smaller elements. The meshing pattern also affects the analysis results to some extent. For example, because all of the elements in the following diagram are orientated at the same angle, an effect referred to as "mesh induced anisotropy" occurs which results in lower computational accuracy.

A meshing pattern that will achieve more accurate results is shown below.

After selecting the plates to be meshed, right-click and select "Mesh Plates" from the menu that appears.

346

Graphical Input

Note that if members also exist around the perimeter of the plates being meshed then they can also be subdivided during the meshing operation if the "Split members along plate edges and connect to newly generated intermediate nodes" option is checked.

After meshing, each plate element must be flat (ie. all vertices in the same plane), have internal angles less than 135 and an aspect ratio less than 4:1.

347


Mirror The Mirror tool allows you to create a mirror image of any user defined nodes, members or plates about any user defined surface. After selecting the nodes, members or plates to be mirrored, right-click and select "Mirror" from the menu that appears. You should then pick a point that lies anywhere in the mirror plane followed by filling out the form shown below.

Don't forget that when picking points in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

348

Graphical Input

Move The Move tool allows you to select one or more nodes, members or plates and move them in any direction on the screen. The renderer version After selecting the nodes, members or plates to be moved, right-click and select "Move" from the menu that appears. You should then pick two points that represent the ends of a vector through which the items are to be moved. Alternatively, if you have only selected one node to be moved, you can choose between "Move Along Vector" or "Move To Location". The "Move to Location" option requires you to pick a destination point rather than two ends of a vector. Don't forget that when drawing in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

The traditional graphics window version There are two ways to move nodes. They are explained as follows. 1. For one node only: Click the toolbar button or select "Move" from the Structure menu and then select the node you wish to move. Move the node and pick its destination point. You can see the members attached to the node being moved and stretched as you move the node. OR For one or more nodes: Select the nodes you wish to move, click the right mouse button and then select "Move" from the floating menu that appears. Pick two points that represent the vector through which the selected nodes are to be moved. Remember that when picking points, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, see "Using the keyboard to position points".

2. All selected nodes are then moved. 3. Select more nodes to move, or press ESC or the right mouse button to exit from the tool. To remove an intermediate node from two members connected end-to-end and convert them into a single continuous member, either use the

349

SPACE GASS 12 User Manual Remove intermediate nodes tool in the renderer or use the Move tool to simply move the intermediate node onto either one of the end nodes.

Be careful when subdividing or connecting to intermediate points on members that have local Y or Z member offsets. Because local offsets are calculated relative to a straight line joining the member’s end nodes, they will change direction if you add intermediate nodes. It is therefore recommended that you should always convert any local Y or Z member offsets to global before adding intermediate nodes.

After moving some nodes, if you are not sure that the members and plates attached to them are properly connected to other nodes, members or plates, you can use the "Connectivity" tool.

350

Graphical Input

Move intermediate nodes You can move intermediate nodes along a member using this tool in the renderer. After selecting the two members on either side of the intermediate node to be moved, rightclick and select "Move Intermediate Nodes" from the menu that appears. In the form shown below, you can enter the distance to be moved or the new member lengths as absolute lengths or as percentages.

351


Moving loads The moving loads tool generates a series of load cases that represent the effect of loads moving along a structure. Common applications include moving or stationary vehicles on a bridge, a crane travelling along a crane rail in a building or material moving along a conveyor. Each load case represents a point in time, and the loads generated from the moving wheels or pressure patches for that load case are distributed onto the closest members or plates.                 

Loads can be moving or stationary. Load sources can be wheeled vehicles such as trucks or cranes, or distributed loads such as pressure patches or line loads. Multiple scenarios allow you to model any combinations of moving and stationary loads. Moving loads can be combined with other static loads. A lane generation tool is included for roads and bridges. Travel paths and lanes can have multiple segments, including curved segments. Loads can be generated on nodes, members and plates. Libraries of standard vehicles are included for various countries. Custom vehicles and libraries can be created. Loads can share common travel paths or lanes. A speed, delay and start position can be specified for each load. Load factors, lane factors and dynamic load allowances can be specified. A loading area can be defined so that loads which move outside of it become inactive. A vertical proximity setting enables independent generation of loads on multi-level roadways or bridges. Moving load data can be exported to MS-Excel, MS-Word or a text file. Moving load data can be imported from MS-Excel or a text file. An animated display allows you to view your loads moving along the structure.

Overview The moving loads tool lets you define sets (scenarios) of moving loads (vehicles, cranes, pressure patches, line loads, etc) that move along your model. As the loads move, SPACE GASS takes a snapshot of their position at a regular time interval and creates a load case for each point in time. If you view the load cases one after another it gives the appearance of the loads moving along the model. Once the moving load cases have been generated you can combine them with other load cases, analyse them or perform design checks on them. In order to proceed, you must first create a moving load scenario that defines a set of load cases to be generated. The scenario has a name, a starting load case number and a time interval that represents the time between load cases. Often only one scenario is required, however you can create multiple scenarios if you wish to examine different situations such as various combinations of vehicles moving along a bridge. You can then add vehicles and/or pressures to the scenario, each of which contains a name, type, magnitude, travel path, load factors, start position, speed and delay. A vehicle consists of a set of wheels (with their positions and loads) and can be defined directly or imported from a standard library. A pressure consists of a width, length, pressure magnitude (in three directions) and load spacing. Each scenario can contain multiple vehicles and pressures, each moving at different speeds, with different magnitudes, starting positions, delays and in different directions if required. The load's speed multiplied by the scenario's time interval defines the distance travelled by the load from one load case to the next.

352

Graphical Input

Stationary loads can be modelled by just specifying a zero speed. Pressure loads with a zero length are also treated as stationary and are applied to the entire travel path length. Stationary loads can be put into just the starting load case or added to each load case that contains moving loads. A travel path, which determines where the vehicle or pressure travels, can have multiple straight or curved segments that can go in any direction or around corners. If multiple loads use the same travel path then it only needs to be created once and can then be shared between all the loads that reference it. Travel paths can be defined graphically or via a data table, plus a travel path generation tool lets you set up your bridge lanes or parallel travel paths quickly in one operation. Finally, you must select the members and/or plates that could be directly loaded by the moving vehicles or pressures. Loads are only applied to the members or plates you have selected, and so for bridges it is normal to select only the members and/or plates in your bridge deck, or for cranes it is normal to select only the beams that the crane wheels are in direct contact with. When the moving loads tool generates the load cases for a scenario, it calculates the position of each vehicle or pressure along its travel path at each point in time and then distributes its loads onto the closest members or plates that support it. Each component of a vehicle or pressure is active if it is within the ends of the load's travel path and within the loading area that you can specify. If you have ticked the vertical proximity distance option then only the members or plates that are within that distance vertically from the vehicle or pressure will be loaded. At any time after creating a scenario, you can produce an animated view of the vehicles and pressures moving along your model. After the loads have been generated, you can use the keyboard PageUp/Dn keys to scroll through the load cases and effectively see the loads moving across your model.

Operating procedure The following steps assume that your job doesn't yet contain any moving load data. If moving load data already exists then you can simply skip the steps for which data already exists. The order of the steps given below is a logical sequence that should work well for most jobs, however other than having to create at least one scenario first, the order is not important and can be changed to suit your desired workflow.

Step 1 - Getting Started You can begin by either: a. Clicking the "Generate Moving Loads" button in the top toolbar without first selecting any members or plates.

This is the recommended most method for most applications. You can set up your travel paths and select the members and plates to be loaded later.

353

SPACE GASS 12 User Manual b. Selecting the members or plates that will be in direct contact with the moving loads, clicking the right mouse button and then selecting "Generate Moving Loads".

This method is recommended if the loads move along a single line of members such as along a crane rail in a building. If the members you select form a single line of members connected end-to-end then the moving loads tool will automatically set up an initial travel path along this line of members, plus it will treat the members you selected as the ones to be loaded. Of course you can change the travel path and the loaded members from inside the moving loads tool at any stage. Regardless of which of the above methods you use to start the process, the selection of the members and plates to be loaded will be remembered by the module and so you don't have to re-select them each time you open the moving loads tool.

Step 2 - Creating a Scenario If no moving load data exists for the job then the "Scenario Properties" form will open automatically, allowing you to create your first scenario. If moving load data already exists then you will be taken to the main moving loads form instead, and you can create a scenario by clicking the "Add Scenario" button.

Each scenario represents a particular configuration of loads moving along your structure. A scenario may contain a number of vehicles, pressure patches or line loads, either stationary or moving at different speeds with different starting positions, delays and in different directions. In many cases you will only need one scenario, however if you are modelling something like

354

Graphical Input a multi-lane bridge then you may need a different scenario for each combination of vehicles in the various lanes. When creating a scenario you must specify a scenario name, a starting load case and a time interval. The name is simply used to identify the scenario and can be any descriptive text. The starting load case is the first in the set of consecutive load cases that will be generated for the scenario, and the time interval is the interval between load cases for the scenario. The finishing load case is calculated automatically for each load and depends on a number of parameters as follows: Finish = Start + (TPLen + LLen - SPos) / (Speed x Interval) + Delay / Interval, where Start is the scenario's starting load case, TPLen is the length of the load's travel path, LLen is the length of the load (eg. 25m for an Australian M1600-6.25 vehicle), SPos is the load's start position along the travel path, Speed is the load's speed, Delay is the load's starting delay and Interval is the scenario's time interval. The overall finishing load case for the scenario is the maximum of the finishing load cases for all of the loads in the scenario. You can also combine the moving load cases with other static load cases by filling out the table at the bottom of the scenario properties form. For more information refer to "Combining scenarios with other static load cases" below.

Step 3 - Adding Loads Once the first scenario has been created, the main moving loads form appears as follows. You are now ready to add loads to the scenario.

Adding loads is simply a matter of clicking the "Add Load" button and then inputting data into the following form.

355


For each load you must specify its type as a vehicle or a pressure, select a travel path, and then specify a start position, speed, delay and load factors. Normally the front of a moving load will start at the beginning of the travel path at time zero and continue until the rear of the vehicle reaches the end of the travel path. Alternatively, you can start your load part-way along the travel path by specifying a non-zero start position and/or you can change its start time by giving it a delay. Delays are very useful if you wish to model vehicles that follow each other on a bridge for example. The speed setting controls the distance each load travels over the scenario's time interval. This distance is also the change in position of the load between successive load cases for the scenario. If you wish to model a reversing vehicle then just specify a negative speed. Note that a reversing vehicle will still move in the same direction along the travel path as a forward moving vehicle. Stationary loads can be modelled by simply giving them a zero speed. Note that the start position and delay settings are still active for stationary loads. If you have a stationary pressure or line load that extends along the entire travel path length, you can model this by specifying a zero pressure length. In this case the speed and start position settings will be ignored. The load factor, lane factor and dynamic factor allow you to factor your loads up or down to satisfy the design code requirements. For example, the lane factor usually depends on how many lanes are loaded and, for 3 lanes or more loaded, it is typically 1.0 for the first lane, 0.8 for the second lane and 0.4 for the other lanes. The dynamic factor is equal to (1 + ), where  is the dynamic load allowance that depends on the type of vehicle being used. All three factors are multiplied together to give an overall load factor and so if a particular factor is not applicable to your situation, such as if you are modelling a crane travelling in a building and so there is no lane factor, you should just set the irrelevant factor(s) to 1.0. The "Generate in" field is enabled for stationary loads and controls whether the load is placed just into the starting load case or into every load case. If you specify "Starting load case only" then the stationary loads will go into the starting load case and the moving loads will begin in 356

Graphical Input the next load case. If you specify "All load cases" then the stationary and moving loads will be combined and will begin in the starting load case.

For a vehicle you can select from a list of vehicles that are already being used in the job, select a vehicle from a library, create a new one or edit an existing vehicle by clicking the following buttons in the "Load Properties" form.

Click this button to select from a list of vehicles that are already in use in the job. Selecting an existing vehicle will allow it to be shared between multiple loads. If there are currently no vehicles in the job then this button will be disabled.

Click this button to select a vehicle from one of the libraries supplied with SPACE GASS or from a custom vehicle library you created previously.

357


Click this button to create a new vehicle or edit an existing one. When editing a vehicle or creating a new one, you must specify a name, together with each wheel's position relative to the front of the vehicle and the forces and moments that the wheel exerts on the structure.

For a pressure you can select from a list of pressures that are already being used in the job, create a new one or edit an existing pressure by clicking the following buttons in the "Load Properties" form.

Click this button to select from a list of pressures that are already in use in the job. Selecting an existing pressure will allow it to be shared between multiple loads. If there are currently no pressures in the job then this button will be disabled.

358

Graphical Input

Click this button to create a new pressure or edit an existing one. When editing a pressure or creating a new one, you must specify a name, together with the width, length, load spacing and magnitude of the pressure. When a pressure is distributed onto the members or plates in your structure it is approximated by a grid of uniformly distributed point loads spaced at the "Load spacing" setting that you specify. If you use a small load spacing then you will get a more accurate load distribution than you would with a large load spacing, however a smaller load spacing will also result in many more loads being generated. If you wish to generate a line load then you should simply specify a pressure width that is less than the load spacing. For example, in order to generate a 6kN/m line load with a load spacing of 0.5m you could specify a width of 0.1m and a pressure of 60kPa. Alternatively, a width of 0.25m with a pressure of 24kPa would give exactly the same result. If you have a stationary pressure or line load that extends along the entire travel path length, you can easily model this by specifying a zero pressure length. In this case the speed and start position settings will be ignored.

Step 4 - Defining Travel Paths Each load in a scenario must be associated with a travel path so that SPACE GASS knows where the load is going. Even stationary loads need a travel path in order to identify their position and orientation. 359


If you are modelling a multi-lane bridge then you should think of each lane as a travel path. Once you have defined the travel path for your first lane you can use the lane generation tool (explained below) to generate the other lanes simply by specifying the lane width and the number of lanes required. In fact, it is often a good idea to skip "Step 3 - Adding Loads" above, set up all your lanes first and then go back to step 3 to add your loads. You can add a travel path or select an existing one by clicking the following buttons in the "Load Properties" form.

Click this button to select from a list of travel paths that are already in use in the job. Selecting an existing travel path will allow it to be shared between multiple loads. If there are currently no travel paths in the job then this button will be disabled.

When selecting a travel path from the above list, if you are unsure of which travel path is which, you can click the "View" button to show them all graphically.

360

Graphical Input

Click this button to create a new travel path or edit an existing one. A travel path consists of a sequence of straight line or curved segments. Each travel path station is defined by a node number and/or X,Y,Z coordinate. If a station is defined by a node number and a coordinate then the coordinate is added to the node position. For example, in the table below, the travel path is parallel to a line joining nodes 1, 43 and 12 and offset 5m in the global Z direction from that line. If you wish to define a travel path station using just coordinates then the node number should be zero for that station. Curved segments can be defined by a non-zero radius at the end of the segment. The travel path below has two segments, each with a radius of 75m. Any radius specified for the first station of the travel path (ie. in the first line of the table) is ignored. If you don't wish to type the travel path stations directly into the table, you can click the "Select Graphically" button and then select the stations graphically by clicking on nodes, members or points off the structure.

If you are modelling a multi-lane bridge then once you have defined the travel path for the first lane, you can use the "Generate Extra Travel Paths" => "Generate Lanes" button in the main moving loads form to generate the other lanes.

361

SPACE GASS 12 User Manual It is just a matter of selecting the first lane in the "Lane to copy from" field, specifying how many extra lanes to generate and the lane spacing. The extra lanes can be generated to the left or right of the first lane. If you're not sure which lane to select in the "Lane to copy from" field then you can click the "View" button next to it to view the existing travel paths graphically before proceeding with the generation. Any curved segments will have their radius increased or decreased in the generated lanes so that the center of curvature of all lanes is maintained. Note that bridge lanes are no different to other travel paths. The only reason they have their own generation form is to make it easier for the user by tailoring the generation input data to lane specific items.

You can also generate extra travel paths by clicking the "Generate Extra Lanes" => "Generate Along Vector" button.

It is similar to the lane generation form above except that the lane spacing field is replaced by a copy vector. Travel paths generated this way will be identical to the original travel path and spaced apart as defined by the copy vector. The radius in curved segments will not be adjusted in the generated copies.

Step 5 - Selecting the Members and Plates to be Loaded Before the moving and stationary loads can be generated, you must specify which members and/or plates in your model that the vehicle wheel loads and pressures are distributed onto.

362

Graphical Input After choosing "Members" or "Plates" from the following menu you should select them graphically either by clicking them directly or via selection windows in the normal way. If your model contains both members and plates that could be loaded then you should select both the members and the plates. Note that you can't select members and plates at the same time and so if you need to select both members and plates then you should select the members first followed by the plates (or vice-versa). It is important that you select all the members and plates that could be directly loaded by the vehicle wheels or pressures because any that are not selected won't be loaded even if a wheel or pressure passes directly over them. Conversely, if you select members or plates that aren't directly loaded (such as sub-structure members below a bridge deck) then they may take loads incorrectly that are supposed to be applied to other members or plates higher up.

Once you have made the member and/or plate selections they will be remembered and saved with the rest of the moving load data. This means that you don't have to re-select them each time you open the moving loads tool. If you selected some members or plates and then opened the moving loads tool via the rightclick menu (ie. using method (b) in "Step 1 - Getting Started" above) then those members or plates will already be selected and you don't have to re-select them here. You can, however, use the "Select Elements to Load" button to edit your selection if required.

Step 6 - Finalizing Your Moving Load Data As you create scenarios, add loads and define travel paths, they will appear in the tree on the left side of the main moving loads form as shown below. You can edit any of your data by clicking the "Add", "Delete" or "Properties" buttons at the bottom, or by clicking the "Edit" button near the top of the right-hand side panel. Better still, you can edit any of your data by just double-clicking the desired item in the tree on the left.

363


In order to visually check the loads and travel paths, you can click the "View" button and then select between loads and travel paths.

Followed by ticking the scenarios or travel paths you wish to view in the following form.

If you select loads then when you click Ok they are shown moving across your model as follows:

364

Graphical Input

Or if you select travel paths then when you click Ok they are shown as follows:

Before generating the moving loads, you need to set the following options correctly.

Normally, loads that don't fall directly on a member are distributed to the closest surrounding members in proportion to their distance from the load, however if the "Apply wheel loads to closest member only" option is selected then each load will be applied only to the member that is closest to it. This reduces the number of loads that are generated while still providing sufficient accuracy in most cases. Each vehicle or pressure is active while it is between normals that extend from the two ends of its travel path. It is possible, however, that you may want wheels or parts of a pressure area 365

SPACE GASS 12 User Manual to become inactive at certain times even though they are still within the extents of the travel path. For example, if a wheel moves off the side of a bridge or moves off the end of a skew bridge, you may want it to become inactive before it reaches the end of its travel path. You can achieve this by clicking the "Ignore loads that transfer load to just one member" option. This has the effect of ignoring wheels or parts of a pressure area that would have their load distributed to just one member unless the load is directly on that one member. It solves the problem of deactivating loads that move off the structure in most cases. For situations in which the above option is not suitable, you can specify a polygon that defines a loading area. Wheels or parts of a pressure area that fall outside of the loading area are treated as inactive. You can define the loading area graphically by clicking the "Select Loading Area" button in the main moving loads form and then selecting points around your model that represent the limits of the loading area.

When loads are distributed onto the surrounding members or plates, their vertical position is usually ignored. The problem with this is that if you have a multi-level bridge for example, any vehicles that are on an upper bridge deck could also have their load incorrectly applied to a lower deck if it is vertically below the vehicle. The "Check vertical proximity" setting solves this problem by only distributing load to the members or plates that are positioned vertically within the "Proximity" distance of the load.

Step 7 - Generating the Moving Loads Once you have created all the required scenarios, loads and travel paths, you should click the Generate button to initiate the load generation. If you don't want to generate data for every scenario then you can disable some of them by unticking them in the tree on the left. In the following example the "M1600 - Heaviest load in centre lane" has been unticked and so it is temporarily disabled and no loads will be generated for it when you click the "Generate" button.

366

Graphical Input

During the generation, each wheel of a vehicle is treated as a load source that has its load distributed onto the structure. Pressure loads are approximated by a grid of equally spaced point loads that are also distributed onto the structure. For each wheel load or pressure point load, if it falls on a plate then it is distributed to the plate's corner nodes in proportion to their distance from the load. If it doesn't fall on a plate then it is distributed to the surrounding members in proportion to their distance from the load or onto a single member if it falls directly on that member or if the "Apply member loads to closest member only" option is ticked. Once the load generation has finished, you can use the keyboard PageUp/Dn keys to scroll through the load cases and see effect of the generated loads moving across your structure. All primary and combination load cases generated with the moving loads tool are given load case titles that reflect their properties. Each title includes a heading and a notes field. Please ensure that you don’t edit or delete the notes field as it is the means by which the program keeps track of which load cases belong to which scenario.

Envelopes After the job has been analysed, you can display bending moment or shear force envelopes by clicking the "Selected Load Cases" item in the load cases combo box in the top toolbar and then typing in the range of load cases that have just been generated for a scenario. For example, if load cases 1 to 35 were generated, you should type 1-35 into the load cases field. Note that this may not always be necessary as the load cases field is automatically set by SPACE GASS for the first scenario whenever moving loads are generated.

367


On the side toolbar, you should then ensure that the envelope button desired bending moment

or shear force

is depressed and the

diagram button is depressed.

Combining scenarios with other static load cases The load cases generated for a scenario can be combined with other static load cases using the table at the bottom of the scenario properties form. This is necessary when the moving loads need to be combined with other load cases such as dead loads, live loads, etc.

For example, in the above form, the scenario 1 moving loads will be combined with static load case 9 to form a set of combination load cases starting at load case 500. A further set of

368

Graphical Input combination load cases starting at 900 will combine the scenario 1 load cases (factored by 0.9) with static load case 6. You can see this has the potential to generate a huge number of load cases and you may, therefore, need to increase the "Maximum load cases" value via the "Problem size limits" item of the Settings menu. If you need to combine a scenario with more than one static primary or combination load case, simply create a combination load case that combines the primary and combination load cases into a new combination load case first and then combine the scenario with that new combination load case. Remember that combination load cases can be combined into further combinations up to four levels deep. Combining scenarios with other load cases increases the risk of overwriting existing load cases and having load case clashes due to overlapping of load cases between scenarios and combinations. SPACE GASS checks for these occurrences and prevents the load generation from proceeding if any problems are detected. If you don't want to use the "Combining with other Load Cases" table in the scenario properties form above then you can also combine sets of load cases using the "Generate" button in the normal combination load cases datasheet. This has the added advantage that you can change your combinations at any time without having to re-run the moving load generation. The following example would combine load case 6 factored by 0.9 with load cases 100-177 factored by 1.0 into combination load cases 900-977. It would achieve exactly the same thing as the second line in the "Combining with other Load Cases" table above.

369


Multiple viewports This tool is only available in the traditional graphics window. SPACE GASS allows you to present more than one view of your structure on the screen at any one time in the traditional graphics window. Up to four different windows, or "viewports", can be displayed and individually configured to better display your structure. The procedure involves clicking the button or selecting "Viewports" from the Window menu. Once you have opened multiple viewports you can page through the different views using the functions).

and

toolbar buttons (the TAB and SHIFT+TAB keys perform the same

When you click the viewport tool you are presented with a number of different configurations. Most of these configurations are self explanatory, with the exception of the bottom four buttons. These four buttons allow you to select any one of the four viewports, either on their own, or in combination. Each corner of the screen corresponds with viewports 1, 2, 3 and 4 respectively. If one of the viewports selected is already displayed it will return to the configuration defined by the diagram on the button selected. Each of the viewports which are displayed have their own unique configuration. This applies to scales, viewpoint, filters, superimposed diagrams, toggle button settings, etc. The configuration you specify for a viewport will be retained when you close the viewport so that, when you open that viewport again, the same settings will be active. You can use the viewports to display a variety of different information including different views of the structure, graphics settings, bending moment, shear force, axial force, stress and displacement diagrams, dynamic and buckling mode shapes, filters, load cases, member top flanges, 3D geometry, local axes, etc. When you select a different viewport (either by clicking on it with the mouse, selecting it via the "Viewport" toolbar buttons or Window menu, or by using the TAB and SHIFT+TAB keys) the settings you have selected for that viewport will be indicated via the toggle buttons.

370

Graphical Input Graphics commands apply to the active viewport. Some graphics commands allow you to move between viewports without exiting from the command. For instance, consider a job where you have 4 viewports displayed with viewport 1 as the active viewport. If you select the draw facility and start drawing a line in the active viewport, you can then move the cursor to any other viewport without exiting from the draw command. You will find that as you move the cursor between the viewports each viewport displays a drawn line which has the same coordinates as in the viewport where you first started drawing the line. This is useful in a number of situations, such as when you start drawing a line in one viewport but cannot locate the end point in that viewport. This feature applies to some graphics functions and can be switched on and off via the "Viewports" form (ie. by toggling the "Activate Viewport Under Cursor" check box in the viewports form).

371


Node loads This tool allows you to graphically apply force and moment loads to nodes. Node loads are always referenced to the global axes system. If you wish to apply node loads in local axes you should use member concentrated loads instead (see also Member concentrated loads). The procedure is as follows. 1. Select the nodes you wish to load, click the right mouse button and then select "Node Loads" from the floating menu that appears. OR Click the toolbar button or select "Node Loads - Graphical" from the Loads menu, select the nodes you wish to load, click the right mouse button and then click Ok.

2. In the load case form that appears, if you are inputting new loads then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing loads then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them. You should then choose between showing the loads applied to each selected node individually (ie. one line of data for each node) or applied as a group to all the selected nodes (ie. one line of data for all the nodes). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected nodes. This can be particularly useful if you are applying the same load to a number of nodes. If you are inputting a different load on each node then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what loads are already applied to the nodes you have selected. If you have elected to show the loads applied to each node individually then you can also choose between showing all the selected nodes or just the ones that are loaded. If you are inputting new loads then you would probably choose to show all the selected nodes, whereas if you are editing existing loads or just viewing loads then showing just the loaded nodes may be preferable.

3. A datasheet then appears with any existing loads shown. You can add, edit or delete loads and then click the Ok button to save any changes. The operation of the datasheet is the same as the non-graphical datasheets (see also Datasheets). 372

Graphical Input

Refer to "Using datasheets" for information on how to operate the above datasheet. See also Node load data.

373


Node properties The node property forms described here are only available in the traditional graphics window. For information about the renderer's property panels, refer to Property panels or The renderer. Node properties include node coordinates, node restraints and master-slave constraints. Hence, selecting the graphical option for "Nodes", "Node restraints" or "Master-slave constraints" will all take you to the same node properties form. There are three modes available for editing node properties as follows. To edit or query node properties one node at a time Simply double-click on a node. Note "Edit/Query Node" in the title bar of the form that appears.

Although this mode only lets you edit the properties of one node at a time, you can simply click on any other node to display and edit its properties without exiting the command. When doing so, any changes you made to the properties of the previously displayed node are saved. You can also press the "Results" button and then click on any nodes to display their analysis results in a scrollable window (see also Query analysis results). To edit or query node properties for multiple nodes using a form Select some nodes graphically, click the right mouse button and then select "Properties (Form)" from the floating menu that appears. Note "Edit Node Properties" in the title bar of the form that appears.

374

Graphical Input

Edit mode works in a similar way to edit/query mode except that you can’t select other nodes while the form is open. You can, however select multiple nodes initially and make changes to all of them simultaneously. Blank fields A blank field indicates that for the nodes selected, more than one value exists. If you leave such a field blank then the selected nodes will retain their individual values. However, if you type into a blank field then all of the selected nodes will receive the new value. Special buttons Shows or hides the master-slave constraints part of the node properties form.

Allows you to graphically select a master node rather than having to type in its node number. To edit or query node properties for multiple nodes using a datasheet Select some nodes graphically, click the right mouse button and then select "Properties (Datasheet)" from the floating menu that appears. Note that the datasheet that appears is different to the normal nodes datasheet because it contains extra columns for restraints and master-slave constraints.


375


You can view node restraints or master-slave constraints graphically by depressing the "View node restraints" or "View master-slave constraints" toggle buttons in the side toolbar.

If you change any node properties that affect the structure’s geometry, you may not be able to select some nodes, members or plates until after a redraw. This is due to their displayed position becoming out-of-date. The "Regen" check box allows you to order an automatic redraw after you exit the node properties form. You can remove restraints and/or constraints by either blanking the restraint or constraint field or by typing "NONE" in the field or by clicking the delete button. See also Nodes. See also Node restraints. See also Master-slave constraints. See also Floating mouse menus. See also View node / member / plate properties.

376

Graphical Input

Node restraints Node restraints are incorporated into node properties. See also Property panels. See also Node restraints. See also Node properties.

377


Notes Notes can be attached to nodes, members or plates, or simply placed anywhere on or near the model.

To add a note you can right-click anywhere in space or on a node, member or plate and then select "Add Note" to bring up the following form. The form lets you set the note's colors, leader length and location. When you click Ok the note appears in the renderer. Notes are saved with the job and stay with the model unless you delete them.

378

Graphical Input

Notes can be turned on or off using the left side of the toolbar, or by clicking the small arrow on the right side of the the notes editor which lets you move, edit or delete notes.

button at the bottom of the side button you can open

379


Ortho This tool is only available in the traditional graphics window. The renderer has other alignment tools that replicate the function of this Ortho tool. The ortho tool limits the lines that you draw to only horizontal or vertical. You can activate ortho mode by clicking the toolbar or selecting "Ortho" from the Settings menu or pressing "SHIFT+CTRL+O" on the keyboard (or just "O" if a graphics command is active). If ORTHO is on, it activates a secondary crosshair graphics cursor which indicates the actual selection point and which moves in such a way that only horizontal or vertical lines (relative to the frame global axes) can be drawn. It is a very useful aid for drawing and positioning members, as most structures contain predominantly horizontal and vertical members. It can be toggled on or off by again clicking the "Ortho Mode" toolbar button or re-selecting the "Ortho Mode" menu item. The current ORTHO setting is displayed on the graphics settings button (as indicated above).

If you are drawing new members with ORTHO on and ATTACH set to "NEAR/END", then the attachment point for any new member which attaches to an intermediate point on another member is positioned so that the new member stays truly orthogonal. You can also use ATTACH set to "ORTHOGONAL" for the same result.

380

Graphical Input

Pan This tool allows you to move the structure in any direction on the screen. It is useful if you cannot see the entire structure at once and you don't want to change the scale. You simply move the structure until you can see the desired portion. The renderer version You can zoom, pan or rotate your model via the mouse scrollwheel or by dragging it around using the left or right mouse buttons as shown below.

The traditional graphics window version Panning can be most conveniently done using the mousewheel or keyboard arrow keys as described in "Shortcuts". For example, while viewing the structure graphically, just hold down the CTRL key and use the mousewheel to pan up or down, or hold down the SHIFT key and use the mousewheel to pan left or right. Alternatively, you can pan by clicking the View menu or the floating menu.

toolbar button or selecting "Pan" from the

The sequence of operation is as follows. 1. Pick two points that represent the relative movement through which the structure is to be panned across the screen. 2. The structure is redrawn at the new position.

The PAN operation does not change node coordinates, it simply translates your viewpoint.

381


Plane The plane tool allows you to specify an operating plane in or parallel to the global XY, XZ or YZ planes in which the graphics cursor will move. The renderer version At any time while drawing lines or just generally moving the mouse cursor, you can see its coordinates displayed in the bottom right-hand corner of the renderer. Depending on the current working plane, you will notice that only two of the coordinates change as you move the mouse and the third one is held constant. You can change the working plane by pressing the X, Y or Z keys or by right-clicking one of the view selector faces or by clicking the working plane button

in the bottom toolbar.

Note that whenever you graphically select a point or a node, the working plane moves to the plane of that point or node. If you have a grid displayed, it is drawn in the current working plane.

For more information about the attachment, alignment, grid and snap tools in the renderer, refer to Attachment and alignment methods, Grid and Snap.

The traditional graphics window version You can change the plane setting by clicking the toolbar button or selecting "Operating Plane" from the Settings menu or pressing "SHIFT+CTRL+P" on the keyboard (or "X", "Y", "Z" or "P" if a graphics command is active). It allows you to accurately move the graphics cursor to any desired position in 3D space.

The current PLANE setting is displayed on the graphics settings button (as indicated above). The "Offset" field is the distance from the operating plane to the structure origin. It can be seen by observing the coordinates display as you move the graphics cursor.

382

Graphical Input

You can often take advantage of the fact that when picking points in any graphics operation, the operating plane offset is changed to match the coordinates of the most recently picked point. If you change the viewpoint such that the operating plane is no longer visible, the program will automatically change the operating plane to a visible one.

383


Plate pressure loads This tool allows you to graphically apply pressure loads to plates. Plate pressure loads can be referenced to the global or local axes systems. The procedure is as follows. 1. Select the plates you wish to load, click the right mouse button and then select "Pressure Loads" from the floating menu that appears. OR Click the toolbar button or select "Plate Pressure Loads - Graphical" from the Loads menu, select the plates you wish to load, click the right mouse button and then click Ok.

2. In the load case form that appears, if you are inputting new loads then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing loads then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them. You should then choose between showing the loads applied to each selected plate individually (ie. one line of data for each plate) or applied as a group to all the selected plates (ie. one line of data for all the plates). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected plates. This can be particularly useful if you are applying the same load to a number of plates. If you are inputting a different load on each plate then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what loads are already applied to the plates you have selected. If you have elected to show the loads applied to each plate individually then you can also choose between showing all the selected plates or just the ones that are loaded. If you are inputting new loads then you would probably choose to show all the selected plates, whereas if you are editing existing loads or just viewing loads then showing just the loaded plates may be preferable.


384

Graphical Input

Refer to "Using datasheets" for information on how to operate the above datasheet. See also Plate pressure data. See also Varying plate pressure loads.

385


Plate properties The plate property forms described here are only available in the traditional graphics window. For information about the renderer's property panels, refer to Property panels or The renderer. Plate properties include plate type, connectivity, orientation of local axes, plate thickness, plate offset and material properties. There are three modes available for editing plate properties as follows. To edit or query plate properties one plate at a time Simply double-click on a plate. Note "Edit/Query Plate" in the title bar of the form that appears.

Although this mode only lets you edit the properties of one plate at a time, you can simply click on any other plate to display and edit its properties without exiting the command. When doing so, any changes you made to the properties of the previously displayed plate are saved. You can also press the "Results" button and then click on any plates to display their analysis results in a scrollable window (see also Query analysis results). To edit or query plate properties for multiple plates using a form Select some plates graphically, click the right mouse button and then select "Properties (Form)" from the floating menu that appears. Note "Edit Plate Properties" in the title bar of the form that appears.

386

Graphical Input Edit mode works in a similar way to edit/query mode except that you can’t select other plates while the form is open. You can, however select multiple plates initially and make changes to all of them simultaneously. Blank fields A blank field indicates that for the plates selected, more than one value exists. If you leave such a field blank then the selected plates will retain their individual values. However, if you type into a blank field then all of the selected plates will receive the new value. Special buttons Allows you to input a material from a standard library. Material properties are different to the other items in the plates form because a single material can be shared amongst many plates. All other items of data in the plates form have their own independent values for each plate. Hence, as soon as you change the material property number, the rest of the material data changes to match. You can scroll through the materials in the current job by changing the material number in the plate properties form. All of the properties that have been defined for that material will be displayed. If no properties have been defined for that material then the name field will be blank, as will the properties fields. To edit or query plate properties for multiple plates using a datasheet Select some plates graphically, click the right mouse button and then select "Properties (Datasheet)" from the floating menu that appears.


You can view plate offsets graphically by depressing the "View offsets" toggle button in the side toolbar.

If you change any plate properties that affect the structure’s geometry, you may not be able to select some nodes or plates until after a redraw. This is due to their displayed position becoming out-of-date. The "Regen" check box allows you to order an automatic redraw after you exit the node properties form. See also Plates. 387

SPACE GASS 12 User Manual See also Material properties. See also Floating mouse menus. See also View node / member / plate properties.

388

Graphical Input

Prescribed node displacements This tool allows you to graphically specify displacements and rotations to nodes. The prescribed displacements are load case specific. Node displacements are always referenced to the global axes system and can only be applied to restrained degrees of freedom. The procedure is as follows. 1. Select the nodes you wish to displace, click the right mouse button and then select "Prescribed Node Displacements" from the floating menu that appears. OR Select "Prescribed Node Displacements - Graphical" from the Loads menu, select the nodes you wish to displace, click the right mouse button and then click Ok.

2. In the load case form that appears, if you are inputting new displacements then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing displacements then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them. You should then choose between showing the displacements applied to each selected node individually (ie. one line of data for each node) or applied as a group to all the selected nodes (ie. one line of data for all the nodes). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected nodes. This can be particularly useful if you are applying the same displacement to a number of nodes. If you are inputting a different displacement on each node then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what displacements are already applied to the nodes you have selected. If you have elected to show the displacements applied to each node individually then you can also choose between showing all the selected nodes or just the ones that are displaced. If you are inputting new displacements then you would probably choose to show all the selected nodes, whereas if you are editing existing displacements or just viewing displacements then showing just the displaced nodes may be preferable.

3. A datasheet then appears with any existing displacements shown. You can add, edit or delete displacements and then click the Ok button to save any changes. The operation of the datasheet is the same as the non-graphical datasheets (see also Datasheets).

389


Refer to "Using datasheets" for information on how to operate the above datasheet. See also Prescribed node displacement data.

390

Graphical Input

Property panels Node, member and plate property panels The node, member and plate property panels operate in two slightly different modes as described below. Mode 1 - When you double-click on a node, member or plate in the model, the appropriate property panel opens and you can make changes and then click the Ok button at the bottom of the panel to confirm the changes. Alternatively, if you make some changes in a property panel and then simply click on a another node, member or plate in your model, the previous changes will be confirmed and the newly selected item's data will appear in the property panel. Mode 2 - If you select one or more nodes, members or plates and then right-click and select "View/Edit Properties" from the menu that appears, the appropriate panel will open with the combined data for all of the selected items. When in this mode, you cannot select other nodes, members or plates until you have clicked the Ok or Cancel buttons at the bottom of the panel. Blank fields indicate that the data is different for the selected items. Be careful with blank fields because if you enter data into one of them then all of the selected items will get that data.

Single selection

Multiple selection

391


Section and material property panels The section and material property panels are located by default on the right hand side of the renderer and are usually closed unless you have them pinned open. To open them simply hover over the tab.

392

Graphical Input

You can open the property panels to view the section and material properties and color match them to the members in your model, or you can click a particular section or material in the panel to have all the matching members in your model selected.

Controlling property panels Property panels can be pinned open by clicking the button at the top of the panel so that it changes to . This means that it will stay open, even if not being used. If you click it again, it changes to , indicating that the panel is not pinned and will close when not required. If you want to close a panel manually then just click

.


393


394

Graphical Input

Query analysis results You can query the analysis results graphically in either of two ways: Using the mouse cursor If you move the mouse cursor onto any load or analysis diagram, the value of the diagram at the cursor position will be shown, together with its location, member number and load case number. Analysis result querying can be turned on or off by clicking the left hand part of the button at the bottom of the side toolbar. If the button is on but analysis results don't appear when you move the mouse over a diagram, click the arrow part of the check that the "Analysis Results Infotips" option is ticked.

button and

Using a scrollable window Right-click on any node, member or plate and then select "Analysis Results" from the popup menu that appears. You can then specify the list of load cases that you want to query or just leave the list blank to see the results for all load cases.

The scrollable results form shown below then displays a useful summary of the analysis results for the node, member or plate you selected.

395


While the form is open, you can simply click on any other nodes, members or plates to have their results displayed. To get a fully detailed analysis report, refer to Output. See also Infotips.

396

Graphical Input

Query frame You can query any node, member or plate in your model by simply double-clicking on it. While the form is open, you can simply click on any other nodes, members or plates to have their attributes displayed. For full details, refer to Node properties, Member properties or Plate properties.

397


Query steel member design results After a steel member design, right-click on any member and then select "Steel Member Design Results" from the popup menu that appears. The scrollable results form shown below displays a useful summary of the design results for the member you selected.

While the form is open, you can simply click on any other members to have their design results displayed. To get a fully detailed steel member design report, refer to Output.

398

Graphical Input

Redraw This tool is not applicable to the renderer, as the model is always kept up to date, however in the traditional graphics window a redraw is sometimes required to "clean-up" the image. You can redraw the graphics display area with the same scale, viewpoint and contents by clicking the menu.

toolbar button or selecting "Redraw" from the View menu or the floating

The REDRAW facility can be useful for removing stray lines or text which are sometimes left after a MOVE, COPY, ROTATE, MIRROR or other graphics operation.

399


Remove crossed member nodes This renderer tool lets you remove nodes that are at the intersection of members that cross over each other, such as you get with wall or roof cross bracing. After selecting the nodes attached to the crossed members, right-click and then select "Remove Crossed Member Nodes" from the menu that appears.

400

Graphical Input

Remove intermediate nodes In the renderer you can remove intermediate nodes by selecting the desired members, rightclicking and then selecting "Remove Intermediate Nodes" from the menu that appears. Note that intermediate nodes can only be removed from members that are straight. For members that aren't straight you can simply use the Move tool to move an intermediate node onto its neighbour to remove it.

401


Renumber The Renumber tool allows you to renumber nodes, members or plates at any stage of the program operation. Items that reference nodes, members or plates such as restraints, constraints, loads and steel design data are automatically adjusted for the new numbering sequence. The renderer version After selecting the nodes, members or plates to be renumbered, right-click and select "Renumber" from the menu that appears. In the form shown below, the "Increment by" option allows you to create a gap in a sequence of nodes, members or plates without having to redefine the entire numbering sequence. You can also renumber in one, two or three directions simultaneously if required.

The traditional graphics window version After selecting the nodes, members or plates to be renumbered, right-click and select "Renumber" from the menu that appears. In the form shown below, the "Increment by" option allows you to create a gap in a sequence of nodes, members or plates without having to redefine the entire numbering sequence.

402

Graphical Input

Note that if a node, member or plate is to be renumbered to a node, member or plate that already exists, SPACE GASS displays an error message and forces you to change the renumbering data before renumbering can proceed.

403


Repeat last command This tool is only available in the traditional graphics window. By pressing the keyboard spacebar, you can repeat the last command. This can be useful in situations where you need to repeat an operation a number of times.

404

Graphical Input

Reverse member direction This tool in the renderer allows you to reverse the direction of selected members so that their local x-axes point in the opposite direction. It effectively swaps the node A and node B numbers in the member data. After selecting the members to be reversed, right-click and select "Reverse Member Direction" from the menu that appears to display the form as shown below. Any options that you tick in the form below will be adjusted so that they are not affected by the reversal, otherwise they will be reversed with the member.

Note that you can see the direction of members using the View member origins tool.

405


Reverse plate direction The Reverse Plate Direction tool lets you reverse the direction of plates, effectively swapping their front and back faces. It also results in the plate’s local x and z axes having their directions reversed.

Original Plate

Reversed Plate

After selecting the selected plates, right-click and select "Reverse Plate Direction" from the menu that appears. If you tick the "Adjust the direction of loads so that they are unaffected by the reversal" option then any plate loads will be adjusted so that they remain in the same general direction as before the plates were reversed. Note that the order of the nodes around a plate are changed after the plate has been reversed.

406

Graphical Input

Rotate The Rotate tool allows you to select one or more nodes, members or plates and rotate them about any user defined axis. After selecting the nodes, members or plates to be rotated, right-click and select "Rotate" from the menu that appears. You should then pick the centre of rotation and then fill out the form that appears below. Note that the sign of the angle of rotation follows the "right hand screw rule".

Don't forget that when picking points in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

407


Scale You can use this tool to apply a scale factor to selected nodes, members or plates. For example, you could use it to enlarge your model by 20% or, if you had mistakenly input your node geometry in millimetre units instead of meters, you could scale the model down by 0.001. After selecting the nodes, members or plates to be scaled, right-click and select "Scale" from the menu that appears. You should then pick a base point about which the scaling occurs, followed by specifying the scale factor in the form shown below.

Don't forget that when picking points in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, see "Aligning, snapping and attachment tools" in The renderer. Remember also that when picking points, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, see "Using the keyboard to position points".

The Scale tool only affects the node coordinates. It doesn’t adjust offsets, section properties, loads or any other parts of your model.

408

Graphical Input

Scales The Scales tool allows you to change the scales of the model or any of the superimposed diagrams. The renderer version You can change the scale of your model by zooming using the mouse scrollwheel or you can change the scale of load or analysis result diagrams by holding down a key while rotating the mouse scrollwheel. For example, to change the scale of your loads hold down the "L" key while rotating the mouse scrollwheel, or use the "D" key for deflections, "M" for moments, "S" for shear forces, "A" for axial forces, "T" for torsions, "B" for buckling mode shapes, or "E" for stresses. Alternatively, you can click the form.

button in the top toolbar to open the following scales

The traditional graphics window version Changing scales can be most conveniently done using the mousewheel or keyboard arrow keys as described in "Shortcuts". For example, while viewing the structure graphically, just use the mousewheel to zoom in or out, or hold down the M key and use the mousewheel to change the scale of a displayed bending moment diagram, etc. Alternatively, you can change scales by clicking the from the View menu or the floating menu.

toolbar button or selecting "Scale"

All scales initially default to values that allow the diagrams to fit neatly into the available graphics display area. If you change any of the scales, they are retained with the job.

409


The "Displacements factor" and "Buckling mode factor" settings are distortion factors rather than scales. Increasing their values causes the relevant diagrams to increase in size. Increasing any of the other "Scale" settings causes the relevant diagrams to be reduced in size.

410

Graphical Input

Sea Loads This tool lets you generate wave, ocean current, marine growth and buoyancy loads on submerged structures in marine and offshore environments where these effects impose significant loading on the affected structure. The procedure for load calculation starts with the analysis of the wave by an appropriate theory to determine the water particle velocities and accelerations at various depths in the water body. The computed velocities and accelerations are combined with any additional water current velocities (tidal, density current, storm velocity, etc), marine growth loads and buoyancy loads for determining the effective loading on individual structural elements. When combining wave and water currents the Doppler effect of the current on the wave is automatically taken into account. Presently, Airy's linear wave theory and Stokes' 5th and 2nd order non-linear wave theories are incorporated into this tool. Sea loads on the structure comprising drag and inertia loading on individual structural members are computed using Morison's equation. The formulation applies strictly to skeletal framed structures with slender tubular members, but can also be applied to framed structures with non-tubular members applying modified coefficients for drag and inertia. The tool is not suitable for the computation of sea loads on large bodies such as vessels, ship-shaped or boxed and/or plate structures where the length to effective diameter ratio of any individual element is small. The sea load generator uses the concept of "scenarios", each of which represents the motion of a wave and generates multiple load cases that correspond with the various positions of the wave. It is normal for a scenario to represent a full wavelength, however you can reduce it to part of a wavelength by changing the "Phase increment" and "Steps" variables so that their product is less than 360 degrees if desired. The procedure is as follows: 1.

From within the renderer, select the members that are flooded, click the right mouse button and then select "Generate Sea Loads" from the floating menu that appears. Note that all of the submerged members in your model will be loaded, regardless of whether you select them or not. The members you select will indicate which of them are to be regarded as "flooded". The unselected (non-flooded) members will be subjected to buoyancy loads if they are tubular, whereas the selected (flooded) members will not.

2.

In the sea load form that appears (as follows), change the data to suit your requirements and then click the Ok button.

411


General Parameters:

The following parameters are general in nature and apply to all the sea load cases. Water depth This is the depth of water above the mudline (or seabed). Mudline level The mudline level is essentially the seabed level. It is the level relative to the global origin of the SPACE GASS model and is negative if the mudline is below the SPACE GASS origin (the normal situation).

412

Graphical Input It may be prudent to set up your model so that its origin is at the waterline and therefore Mudline level = - (Water depth). This also means that any "Levels" such as the mudline level, marine growth levels or ocean current levels would always be negative if below the waterline. Water density The normal density of water. Kinematic viscosity This varies with the water temperature. The default value is based on a water temperature of 15 deg C. Surface roughness The surface roughness affects the drag of the water on the structure. The surface roughness value you specify is only used on surfaces that have no marine growth. For surfaces that have marine growth the surface roughness is taken as the marine growth thickness up to a maximum of 50mm. Member segments The number of segments that a distributed load is broken into along a member to simulate the curved profile of the applied load. Marine growth load case This is the load case that the self weight of the marine growth will go into. Because marine growth doesn't change with waves or currents its self weight is put into its own load case. You can the combine it with the wave and current load cases using combination load cases in the normal way. CDM parameters These are the drag (CD), inertia (CM) and lift coefficients that are used in the sea load calculations on submerged members. Guidance for selection of these parameters is available in various code standards including API RP 2A. In the absence of any other information you could consider using CD=0.65 & CM=1.60 for clean tubular members or CD=1.05 & CM=1.20 for fouled tubular members. Values of CD and CM for other cross section types may be obtained from international codes and standards including DnV codes. The "Smooth" coefficients are used if k/D <= 0.0001, the "Rough" coefficients are used if k/D >= 0.01 and an interpolation between the "Smooth" and "Rough" coefficients are used if 0.0001 < k/D < 0.0, where k is the surface roughness and D is the largest dimension or diameter of the member.

Marine growth parameters Any structural element submerged in water will have marine growth developed on its wetted surfaces. Such growth effectively increases the element's exposed area to waves which in turn attracts higher wave loading. For this reason the marine growth parameters applicable to the region where the structure is located needs to be considered in the sea load analysis.

413

SPACE GASS 12 User Manual At least two lines of marine growth data are required, with the marine growth only occurring between the levels and not outside them. If the thickness or density is different in adjacent levels then they are assumed to vary linearly between the levels. Marine growth levels are relative to the SPACE GASS origin and are negative if the location is below the origin.

Scenarios Each scenario represents the motion of a wave and normally covers a full wavelength. If the "Selection Criterion" is set to "None" then multiple load cases representing the various positions of the wave are generated for each scenario. If the "Selection Criterion" is set to "Maximum overturning moment" or "Maximum base shear" then only one load case will be generated for each scenario. You can specify multiple scenarios, each with its own direction and load case(s).

The following parameters are scenario specific.

414

Graphical Input

Load case / Starting load case This is the first of the load cases that will be generated for the current scenario. If the “Selection Criterion” is set to “None” then the last load case for the scenario = Starting load case + Steps – 1, otherwise there is only one load case per scenario. Still water depth Is based on the general water depth, but also includes any tide and/or storm surge at the time of occurrence of waves. It cannot be less than the general water depth. Wave kinematics factor Guidance for selection of the wave kinematics factor is available in various code standards including API RP 2A. In the absence of any other information you could consider using 0.85 to 0.95 for extreme cyclonic or storm waves, or 1.00 for normal operating and fatigue waves. Wave height The wave height is the vertical distance between the wave crest and the trough. Wave period The wave period is the time it takes for the wave to travel through one wavelength (ie. the distance between consecutive wave crests) relative to a stationary point. The sea load output also reports the "Apparent Period", which is the wave period relative to a point travelling with the current (if a current exists). A current in the wave direction tends to stretch the wavelength and increases the apparent period, while an opposing current shortens them. This is the Doppler effect of the current on the wave. Start phase and phase increment Sea loading on a marine structure varies continuously as the wave passes through the structure with the maximum loading occurring at a specific position of the wave with respect to the structure. To determine the maximum loading, the wave is simulated to pass through the structure beginning with the start phase position and stepping the wave at the specified phase increment. A phase of 0 degrees corresponds with the wave crest at the origin (ie. the 0,0,0 position) of your model. 360 degrees is equivalent to one wavelength. Steps This is the number of phase increment steps considered during the analysis. End phase = Start phase + (Steps x Phase increment). If the “Selection Criterion” is set to “None” then the number of load cases generated for a scenario is equal to the number of steps, otherwise there is just one load case per scenario.

415


Wave theory Selection of the wave theory for analysis of any wave depends on the wave parameters and the water depth. A general guidance for selection of the wave theory can be obtained from the American Petroleum Institute's Recommended Practice API RP 2A. In the absence of other information the following could be considered as a rough guideline: if 0.000 <= H/(g.T^2) <= 0.001 and 0.01 <= d/(g.T^2) <= 0.2 then select Airy's linear theory if 0.001 <= H/(g.T^2) <= 0.02 and 0.005 <= d/(g.T^2) <= 0.2 then select Stokes' 5th Order non-linear theory where H = wave height, d = still water depth, T = wave period and g = gravitational acceleration. Selection criterion Sea loading on the structure is evaluated at each position of the wave as it passes through the structure and, depending on the "Selection criterion" specified in the form, the critical position is selected as the position of the wave that results in the maximum base shear or the maximum overturning moment at the mudline. If set to "None" then a load case is generated at each wave position and no attempt is made to determine the critical one. Note that the base shear and overturning moment calculations are based on the horizontal wave and current loads only and exclude any vertical loads from buoyancy, self weight, marine growth or other applied loads. Wave and current direction These are the directions of the approaching wave and water current relative to the global Xaxis. Direction angles are positive anti-clockwise from global X when viewed in plan. Ocean currents Currents occurring simultaneously with waves significantly influence the total sea loading and need to be considered in the analysis. Current profiles should be input for each scenario. They are combined with the wave velocities determined by the wave analysis before Morison's equation is applied. At least two lines of ocean current data are required, with the currents only occurring between the levels and not outside them. If the current is different in adjacent levels then it is assumed to vary linearly between the levels. Ocean current levels are relative to the SPACE GASS origin and are negative if the location is below the origin. The "Blockage Factor" controls how much the current stream in the vicinity of the structure is reduced from the specified "free stream" value by blockage. In other words, the presence of the structure causes the incident flow to diverge. Some of the incident flow goes around the structure rather than through it, and the current speed within the structure is reduced. Blockage factors ranging from 0.7 to 1.0 are typical, with 1.0 representing no blockage.

416

Graphical Input

Doppler effect When waves and currents occur together, an "Apparent Period" relative to the current is determined, accounting for the Doppler effect of the current on the wave. A current in the wave direction tends to stretch the wavelength and increases the apparent period, while an opposing current shortens them. The apparent wave period is determined from API RP 2A Figure 2.3.1-2 if -0.015 <= V/gT <= 0.025, where V is the current component in the wave direction, g is the acceleration due to gravity and T is the actual wave period relative to a stationary point. If V/gT is outside of the above mentioned limits then a warning is issued and the results may not be accurate.

417


Section properties Section properties are incorporated into member properties. See also Property panels. See also Section properties. See also Member properties.

418

Graphical Input

Select all The Select All tool lets you quickly select all visible nodes, members or plates and then perform an operation on them. The procedure is as follows. 1. Click the right mouse button and then select "Select All" from the floating menu that appears. Alternatively, press Ctrl-A on the keyboard or select "Select All" from the Structure menu. The visible nodes, members or plates are highlighted graphically the same as if you had selected them by picking them with the mouse. Note that any nodes, members or plates outside the graphics window or those that are suppressed due to being filtered out are not selected.

2. You can then click on a toolbar button or click the right mouse button and choose from the floating menu that appears to perform an operation on the selected items. You can cancel the highlighting by pressing the keyboard ESC key or by selecting "Cancel" from the floating menu.

419


Selection methods You can select nodes, members or plates directly by clicking them with the left mouse button or you can use a selection window. If the second corner of the selection is to the right of the first then it is a "Normal" selection window in which only the nodes, members or plates that fall completely within the window are selected. Alternatively, if the second corner is to the left of the first then it is a "Crossing" selection window in which any nodes, members or plates that are within the window or which cross the boundary of the window are selected. A normal selection window is drawn as a rectangular box, whereas a crossing window is shown as a filled rectangle. The two types of selection window are shown below. In order to de-select nodes, members or plates, you simply select them again, either by clicking directly or by using a selection window. Normal selection window


420

Graphical Input

Note that you can select all nodes, members or plates by holding down Ctrl and pressing the A key.

421


Self weight Self weight or self mass can be input into any load cases by simply specifying the acceleration due to gravity in any of the three global axis directions. You can open the self weight datasheet by clicking the toolbar button or selecting "Self Weight" from the Loads menu and then entering data into the datasheet as explained in Self weight data.

See also Datasheet Input.

422

Graphical Input

Snap The snap tool causes the cursor to move in discrete steps and allows you to accurately position points on an imaginary snap grid.

The renderer version The Snap tool which can be turned on or off via the snap button in the bottom of the side toolbar or by pressing the S key. The snap spacing can be set to any desired increment or it can be made to match the currently displayed grid spacing.

For more information about the attachment, alignment, grid and working plane tools in the renderer, refer to Attachment and alignment methods, Grid and Plane.

The traditional graphics window version You can activate snap mode by clicking the toolbar or selecting "Snap" from the Settings menu or pressing "SHIFT+CTRL+S" on the keyboard (or just "S" if a graphics command is active). It allows you to accurately position the graphics cursor. The SNAP facility can be set to any desired increment which may or may not match the GRID setting (as desired). The SNAP increment uses the same system of units as the structure being displayed. It can be toggled on or off by again clicking the "Snap" toolbar button or re-selecting the "Snap" menu item. The current SNAP setting is displayed on the graphics settings button (as indicated above).

423


For convenience, SNAP is automatically turned off temporarily during some graphics operations such as when you are simply picking members. This avoids the problem of not easily being able to pick objects due to the SNAP stepping effect.

When SNAP is turned off, you may notice that the graphics cursor moves in very small increments which are not useful fractions of whole numbers. These increments actually represent the distance between pixels on the screen. When you position the cursor on a known point, the coordinates display sometimes indicates that the cursor is not exactly on the point. This is because there is no pixel exactly on the point and the cursor has therefore moved to the closest pixel. SPACE GASS, however ignores the small movement to the closest pixel and assumes that the cursor is located exactly on the desired point. When SNAP is turned on this does not occur.

424

Graphical Input

Spectral loads Spectral loads must be defined for each load case that you wish to include in a dynamic spectral response analysis. You can open the spectral loads datasheet by selecting "Spectral Load Data" from the Loads menu and then entering data into the datasheet as explained in Spectral load data.

Note that spectral curves can be created, imported or exported via the spectral curve editor. For more information, refer to Spectral curve editor. See also Datasheet Input.

425


Static load to mass conversion Static loads such as dead loads and live loads can be converted to masses if you want to use them in a dynamic analysis and you don't want to re-enter them from scratch as masses. You can select the "Static Load to Mass Conversion" option from the Loads menu in the renderer to bring up the form below. You can convert a number of static load cases at once by entering them as a list in the "Static load case list" field. You must also enter a corresponding list of mass load cases in the "Mass case list" field. They can have the same load case numbers as the static loads, however for your own organizational purposes it is usually a good idea to keep them separate. It is usual to have the "Create mass in all three directions regardless of static load direction" option ticked, as masses generally have inertia in all three directions. As such, static loads that have components in more than one direction on a single object are first resolved into the resultant direction and then converted to a single mass. Alternatively, if the "Create mass in all three directions..." option is not ticked then the masses will simply be placed in the same directions as their source static loads. If the "Delete masses in destination mass cases first" option is ticked then all masses in the destination mass cases will be deleted first, otherwise they will be added to.

Note that self weight static loads are not converted with this tool because self mass can be generated automatically in the dynamic analysis. Note also that moments and torsions are not converted to rotational masses.

426

Graphical Input

Stretch The Stretch tool lets you stretch all or part of your model. After selecting the nodes, members or plates to be stretched, right-click and select "Stretch" from the menu that appears. You should then pick an anchor point, plus two points that represent the ends of a vector through which the items are to be stretched. Each selected item is then moved parallel to the stretch vector by an amount that is proportional to its distance from the anchor point. The distance by which a point is moved parallel to the stretch vector is given by:

where D is the distance moved, Lv is the length of the stretch vector, Dn is the distance from the node to the anchor point in the direction of the stretch vector, and Dv is the distance from the start of the stretch vector to the anchor point in the direction of the stretch vector.

Don't forget that when drawing in the renderer, you can attach to other nodes or members, or you can "lock on" to a node or member and then align with an orthogonal line or an extension line from the "locked on" node or member. You can also align with one of the three global axes. For more information, refer to Attachment and alignment methods. Remember also that when drawing, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, refer to "Using the keyboard to position points".

427


Subdivide The Subdivide tool allows you to select one or more members and subdivide them by inserting intermediate nodes at regular or irregular positions along them. After selecting the members to be subdivided, right-click and select "Subdivide" from the menu that appears. You should then specify the number of subdivisions and their spacing in the form shown below. If the node insertion points are irregular, you can nominate "Insertion points" to be expressed as inclined distances, or as projected distances along one of the global axis directions. Naturally, you cannot nominate projected distances along a global axis which is at right angles to the axis of the member being subdivided. Insertion points are referenced from the node A end or Node B of the members. They can be expressed as actual distances or as percentages. For example, to subdivide a 10m beam into 2m, 3m, and 5m beams, you could type 2,5, or 2,50%, or 20%,50% into the "Insertion points" field. In all three cases, the final result is the same. If you are using percentages for all of the insertion points, then the inclined or projected axis specification is irrelevant.

Subdividing relative to an external point If you wish to subdivide members relative to a point external to the members then you should choose the "Point" option, click the "Select" button and then select the point to subdivide from. This point can be a node or any point in space. For example, if you have a model in which you want to subdivide all the columns at a level that is 5.5m from the ground, you could select all the columns and then from within the subdivide tool, choose "Y-axis projected distances" (assuming Y is vertical), choose the "Point" option and select a point that is at ground level.

428

Graphical Input

Taper plates For retaining structures such as tanks or retaining walls, a varying wall thickness can be generated using this tool. The tool works by you defining the thickness at the start and finish of the taper and a "taper axis" along which the taper is defined. The taper is then projected normal to the axis onto each plate that you have selected. The thickness of each plate is then set according to its projected distance along the taper axis. Note that after applying a taper, each plate still has a uniform thickness but the thickness varies from one plate to the next. The lateral position of each plate relative to the taper axis is not important. For example, a plate a long way from the axis will get the same thickness as a plate close to it. Similarly, a plate on one side of the axis will get the same thickness as a plate on the other side. Plates that are beyond the ends of the taper axis are given the thickness at the closest end of the axis. For example, if you have a tank that is 4m high and the taper axis extends from the base of the tank (with a starting thickness of 300mm) vertically up to the 3m mark (with a finishing thickness of 100mm), the plates in the top 1m of the tank walls would be given the 100mm thickness. The procedure is as follows. 1. Select the plates you wish to taper, click the right mouse button and then select "Taper Plates" from the floating menu that appears. OR Select "Taper Plates" from the Structure menu, select the plates you wish to taper, click the right mouse button and then click Ok.

2. Pick two points that represent the axis along which the taper will be defined. Remember that when picking points, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, see "Using the keyboard to position points".

3. In the form that appears (as follows), change the data to suit your requirements and then click the Ok button.

When applying the thickness to each plate, you can specify whether the new thickness is applied to the front face, back face or both faces. This is achieved by applying an

429

SPACE GASS 12 User Manual offset to each plate so that you can effectively align the adjusted plates by their front face, back face or centerline. If you applying a taper to plates that have already been tapered then you should generally untick the "Keep plate offsets" option so that the offsets are not doubled up. 4. The thicknesses are then calculated and applied to the selected plates.

430

Graphical Input

Taper/haunch generation The Taper/Haunch generation tool lets you model tapered members with or without haunches. A member can be tapered by varying its depth, width or both depth and width. If the depth is varied, the taper can be applied to the top of the member, the bottom of the member, or evenly to both the top and bottom. If the width is varied, the taper is applied evenly to both sides of the member. If a haunch is selected, its depth is varied and is applied to the bottom of the haunch only. SPACE GASS uses a series of prismatic member segments to approximate the exact taper. You can use up to 50 segments per taper, however usually 3 segments is enough to get very close to the exact solution. The cross section dimensions for each prismatic member can be set equal to the taper’s largest end dimensions, smallest end dimensions or average dimensions for the segment under consideration. After selecting the members to be tapered or haunched, right-click and select "Generate Taper/Haunch" from the menu that appears. If you have selected more than one member then they must be a continuous run of members with no gaps in-between. Each selected member will become a segment of the total taper or haunch. Alternatively, if you have selected just one member then it will be subdivided as part of the taper/haunch process. The member that you select first determines the start of the taper/haunch. If there was only one member then the node A end will be the start of the taper/haunch. If you selected the members using a selection window or if you selected an intermediate member first, the start of the taper/haunch will be at the end with the lowest numbered member. The following form shows an example of generating a taper.

The following form shows an example of generating a haunch.

431


Note that whenever a taper or haunch is generated, member offsets are also calculated and applied to the tapered/haunched members. The offsets take into account the changed centroid location in the built-up sections and ensure that the tapered/haunched members are correctly positioned relative to each other. If you applying a taper or haunch to members that have already been tapered or haunched then you should generally untick the "Keep member offsets" option so that the offsets are not doubled up.

432

Graphical Input

Textures Textures can be applied to members and plates depending on their material. For example, if the material name starts with "Steel" then the steel texture is used, or if it starts with "Conc" then the concrete texture is used. Textures are also available for aluminium, timber and brickwork. They can then be turned on or off via the toolbar.

button in the bottom of the side

Textures off

433


Textures on

434

Graphical Input

Thermal loads This tool allows you to graphically apply thermal loads to members or plates. The procedure is as follows. 1. Select the members or plates you wish to load, click the right mouse button and then select "Thermal Loads" from the floating menu that appears. OR Select "Thermal Loads - Graphical" from the Loads menu, select the members or plates you wish to load, click the right mouse button and then click Ok.

2. In the load case form that appears, if you are inputting new loads then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing loads then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them. You should then choose between showing the loads applied to each selected member or plate individually (ie. one line of data for each member or plate) or applied as a group to all the selected members or plates (ie. one line of data for all the members or plates). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected members or plates. This can be particularly useful if you are applying the same load to a number of members or plates. If you are inputting a different load on each member or plate then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what loads are already applied to the members or plates you have selected. If you have elected to show the loads applied to each member or plate individually then you can also choose between showing all the selected members or plates, or just the ones that are loaded. If you are inputting new loads then you would probably choose to show all the selected members or plates, whereas if you are editing existing loads or just viewing loads then showing just the loaded members or plates may be preferable.


435


Refer to "Using datasheets" for information on how to operate the above datasheet. See also Thermal load data.

436

Graphical Input

Transparency When in rendered mode, the appearance of members, plates, diagrams and filtered out items can be adjusted to be fully or partially transparent by clicking the side toolbar.

in the bottom of the

The transparency can then be adjusted by sliding the transparency controls followed by clicking anywhere in the graphics area of the renderer.

The following before and after images show how members and plates can be made to look transparent.

437


438

Graphical Input

Varying plate pressure loads For retaining structures such as tanks or retaining walls, or structures subjected to other variable pressure distributions from wind and the like, the resulting pressure loads on plates can be generated using this tool. The pressure variation can be linear or based on an equation that you specify. The tool works by you defining the pressure variation and a "load axis" along which the pressure distribution is defined. The pressure is then projected normal to the load axis onto each plate that you have selected. The lateral position of each plate relative to the load axis is not important. For example, a plate a long way from the load axis will get the same pressure as a plate close to it. Similarly, a plate on one side of the load axis will get the same pressure as a plate on the other side. For calculating the pressure on the walls of tanks or retaining structures, the load axis would normally be vertical and the pressure on a plate with its centre at height h would be the same as the pressure on the load axis at height h. For other structures, such as a distribution of wind loads applied to a roof, it might be more convenient to have the load axis horizontal or maybe even parallel to the roof slope. Plates that are beyond the ends of the load axis are not loaded. For example, if you have a tank that is 4m high and the load axis extends from the base of the tank vertically up to the 3m mark, the plates in the top 1m of the tank walls will not be loaded.

Load Axis and Pressure Distribution

439


Resulting Pressure Applied to the Plates

If the pressure variation is defined by an equation, the equation must have "x" as the variable representing the distance along the load axis and can include any of the operators "+", "-", "*", "/", "\”, "%" and "^". It can also include any of the functions sin, cos, tan, asin, acos, atan, sqrt, factorial, abs, log, ln and exp. For example, the pressure on the walls of a bulk solids container could be represented by the equation Pressure =  rc(1-e(-z/z0))/, where, for a typical coal container could have values of  =10.8, rc=0.88, z0=4.03 and =0.62. This could be entered into the SPACE GASS equation field as 10.8*0.88*(1-exp(-x/4.03))/0.62, where "x" is the distance along the load axis and represents "z" in the original equation.

The procedure is as follows. 1. Select the plates you wish to load, click the right mouse button and then select "Varying Pressure Loads" from the floating menu that appears. OR Select "Varying Plate Pressure Loads" from the Loads menu, select the plates you wish to load, click the right mouse button and then click Ok.

2. Pick two points that represent the load axis along which the pressure variation will be distributed. Remember that when picking points, you can use the mouse or you can simply type in the coordinates of the desired point(s). For more information, see "Using the 440

Graphical Input keyboard to position points".

3. In the form that appears (as follows), change the data to suit your requirements and then click the Ok button. The graph at the bottom of the form represents the shape of the pressure variation along the load axis.

The pressure variation can be linear for cases such as tanks subjected to hydrostatic loads or, for more complex profiles, can be defined by an equation that you specify as explained above. If you specify "Local" axes then the pressure load will be applied in the local z-axis direction (ie. normal to the plane of the plate). If you specify "Global" axes then you must also specify a global XYZ vector that represents the direction of the pressure load.

441

SPACE GASS 12 User Manual 4. The pressure loads are then calculated and applied to the selected plates.

See also Plate pressure data.

442

Graphical Input

View buckling mode shapes After a buckling analysis, you can display the buckling mode shapes by clicking the toolbar button or selecting "Buckling Mode Shapes" from the View menu. You can limit the number of buckling modes shown by defining a filter and specifying a list of the buckling modes required. For 2D models, it is a good idea to view the buckling mode shapes from a 3D viewpoint so that any out-of-plane buckling modes can be observed.

443


View diagrams You can show loading diagrams, displacement diagrams, bending moment diagrams, shear force diagrams, axial force diagrams, torsion diagrams, stress diagrams and reactions by clicking the , , , , , matching items in the View menu.

,

or

toolbar buttons or selecting from the

Diagrams of different types can be superimposed together. For example, it is possible to include both bending moment and shear force diagrams together. In addition, diagrams can be toggled on and off by clicking the button repeatedly.

444

Graphical Input

View dynamic mode shapes After a dynamic frequency analysis, you can display animated mode shapes for all the modes analysed by clicking the View menu.

toolbar button or selecting "Dynamic Mode Shapes" from the

Once initiated, the following keyboard commands are available. Operation Display mode shapes 1 to 9 Display the next mode shape Display the previous mode shape Change to load case Change the display from animated to static Change the display from static to animated Increase the amplitude (scale) Decrease the amplitude (scale) Increase the frequency (speed) Decrease the frequency (speed)

Keystrokes 1-9 Page down Page up C S A Right arrow Left arrow Up arrow Down arrow

You can exit from the dynamic mode shapes commands by pressing ESC or the right mouse button. This also causes any animation to stop and revert back to a static display.

If you use REDRAW or any other tool which causes the graphics display area to be regenerated while a dynamic mode shape is displayed, it will revert back to an animated display, and the dynamic mode shapes commands will again become active. Some examples of mode shapes for a plane grid from the dynamic frequency analysis module are shown following.

1st dynamic mode shape for plane grid

4th dynamic mode shape for plane grid

445


View envelope You can display an envelope of any currently displayed diagrams by clicking the button or selecting "Envelope" from the View menu.

toolbar

You can specify (a) just minimums, (b) just maximums, (c) both minimums and maximums or (d) absolute maximums. The load cases included in the envelope are the ones currently selected and displayed in the load case selection combo box in the top toolbar. If you change the load case selection then the envelope will be updated accordingly. Envelopes of analysis results can also be obtained in output reports, including envelopes that take their maximums and minimums from end A, end B or both ends of a member. For more information, refer to Output

446

Graphical Input

View global origin You can show the global origin by clicking the (renderer) or (traditional graphics window) toolbar button or selecting "Global Origin" from the View menu.

447


View labelling and annotation The renderer version You can show various text labelling and annotation options by clicking the down arrow part of the button in the side toolbar. Once you have selected or de-selected the desired labelling items you can click the Ok button at the bottom or must click anywhere in the graphics area to have the labelling change applied.

Clicking the "More options..." item takes you to the following form from where you can change colors, formatting, etc.

448

Graphical Input

The traditional graphics window version You can show various text labelling and annotation options by clicking the toolbar button or selecting "Labelling and Annotation" from the View menu or the floating menu.

449


450

Graphical Input

Load case titles viewer The load case titles viewer can be opened from within the renderer by clicking the load case titles viewer button . The viewer stays open until you close it or change jobs. It is a handy means of seeing the details of your load cases while you are working with other tools.

Note that many of the load case input fields have a button next to them. Clicking this button also lets you see which load cases exist in your job, plus you can select from the displayed list.

451


Load case titles can be input via the load case titles datasheet from within the traditional graphics window. For more information refer to Load case titles. You can also input/edit load case titles via the combination load cases grid in the renderer by right-clicking a column heading or a cell in the first column.

452

Graphical Input

View local axes You can show the member and plate local axes by clicking the "Local Axes" from the View menu.


453


View manager In the renderer you can save the current view for later recall by clicking the button in the top toolbar or by right-clicking anywhere in the graphics area and then selecting "Save View" from the menu that appears. The view is saved as soon as you enter a name and click Ok in the form shown below.

The view manager (located in a panel on the right side of the renderer) lists all of the saved views. You can recall a view by simply clicking on it in the View Manager panel.

Note that the View Manager panel can be pinned open by clicking the button at the top of the panel so that it changes to . If you click it again, it changes to , indicating that the panel is not pinned and will slide closed as soon as you move away from it. Note also that you can drag the View Manager panel away from the side of the renderer and dock it to another location or you can just place it anywhere on your screen.

454

Graphical Input

View member origins It is often useful to be able to see at which end of a member is its origin, as it affects the placement of member fixities, offsets, loads, etc. You can show the member origins (shown in red below) by clicking the

button in the bottom toolbar of the renderer.

Note that you can reverse the direction of members using the Reverse member direction tool.

455


View node / member / plate properties You can show graphical representations of node restraints, member hinges, master-slave constraints or offsets by clicking the , , or toolbar buttons or selecting "Node Restraints", "Member Hinges", "Master-Slave Constraints" or "Offsets" from the View menu.

456

Graphical Input

View nodes / members / plates You can show or hide nodes, members or plates by clicking the , or buttons or selecting "Nodes", "Members" or "Plates" from the View menu.

toolbar

If the nodes, members or plates are hidden then any tools that require nodes, members or plates to be selected are suppressed. For example, if the nodes are hidden then node loads cannot be input or edited graphically.

457


View plate contours You can use the 3D renderer to show colored contour diagrams for plate forces, moments and stresses by clicking the

toolbar button or selecting "Plate Contours" from the View menu.

The following form allows you to select the type of contour diagram you wish to display as well as specifying its smoothing, color and labelling settings.

If contour smoothing is turned on then the contours appear as continuous color gradients rather than a discrete color for each plate element. Contour diagrams are generated from the force, moment and stress values at each node. The value at a given node can be determined by simply averaging the values from each element that connects to it (non-weighted averaging) or the contribution from each element can be weighted depending on how far the centre of the element is from the node (weighted averaging). For full details of the force, moment and stress contours that can be displayed, refer to "Sign conventions". The colors in a contour diagram can be changed by double-clicking any of the three color icons and then selecting the desired color, or by clicking the "Color Picker" button. If you wish to display the full range of contour values, ensure that the "Full range" option is ticked. If not, you can "zoom in" on a particular range of contour values by unticking the "Full range" option and specifying upper and lower limits. Values that fall within the upper and lower limits will be colored depending on where they fall within the specified color

458

Graphical Input spectrum, and any values that fall outside the limits will be given the same color as values that fall on the upper and lower limits. If you find that the contour diagram is predominantly showing the "middle" color, you may be able to display more color detail by setting a narrower contour range. Each plate can be labelled with its contour value if desired.

459


View results in local XY or XZ plane You can restrict the bending moment, shear force or stress diagrams to either or both of the member’s local XY or XZ planes by clicking one of the or toolbar buttons or selecting "Results in Local XY Plane" or "Results in Local XZ Plane" from the View menu.

460

Graphical Input

View steel member design groups You can switch into steel member viewing mode by clicking the toolbar.

button in the side

This causes the display to switch from this:

to this:

The steel members are shown slightly shorter than their actual length so that you can easily see where they start and finish. When in steel member viewing mode the steel group numbers can be displayed instead of the analysis member numbers as shown in the second diagram above. The numbers can be turned on via the "Show steel member numbers" item in the

button in the side toolbar.

You can also hover over any steel member while in steel member viewing mode to display its steel input data in an information panel as shown below. If the information panel doesn't appear then you should turn it on via the "Show Infotips" button side toolbar.

at the bottom of the

461


To view or edit the properties of a steel member you can simply click the right mouse button on any part of a steel member and then select "View/Edit Steel Member (Form)" from the popup menu that appears. Note that this can be done regardless of whether you are in steel member viewing mode or not. You cannot select individual analysis members while you are in steel member viewing mode. See also Steel member design data

462

Graphical Input

View steel member design results If a steel member design has been performed, this tool shows the design results color coded for the various levels of load factor or stress ratio achieved. You can view the design results by clicking the


You can also change the pass/fail colors and threshold values by clicking the arrow on the right of the

button.

463


To view brief design result details of a steel member design group (see below) you can simply click the right mouse button on any part of a design group and then select "Steel Member Design Results" from the floating menu. You can then simply click on other members to view their results. Note that this can be done regardless of whether the design results are displayed or not.

You can also use filters to restrict the display of members based on their design results.

464

Graphical Input

See also Steel member design data

465


View steel member flange restraints If you are not sure where your steel design flange restraints are actually located along the members, you can use this tool to show them graphically. You can show the flange restraints by clicking the


Displays all of the flange restraints that you have specified for each design group. The flange restraints are shown adjacent to their location on the top and bottom flanges. See also Steel member design data

466

Graphical Input

View steel member top flanges It is important to know which is the top flange for steel members so that the restraints you specify for the top and bottom flanges do not get mixed up. This tool lets you display them as small triangles that touch the top flange of each analysis member. You can show the top flanges by clicking the


The top flange for a steel design group is taken to be the same as the top flange for the first analysis member in the design group. Therefore, to find the top flange of a design group you must look at just the first member in the group. See also Steel member design data

467


Viewpoint This tool allows you to rotate your viewpoint around the structure. You can obtain an elevation from any side, a plan view or a view from any other position. In the renderer you can also switch between orthographic and perspective viewing modes. The renderer version You can zoom, pan or rotate your model via the mouse scrollwheel or by dragging it around using the left or right mouse buttons as shown below.

Rotate the viewpoint by holding down the left mouse button while moving the mouse. An alternative to rotating the model by dragging it around directly is to drag the view selector around. You can also click one of the view selector faces, edges or corners to go straight to a specific viewpoint. If you click on the small square attached to the front face it will take you to the 30,10 viewpoint.

The traditional graphics window version Changing the viewpoint can be most conveniently done using the mousewheel or keyboard arrow keys as described in "Shortcuts". For example, while viewing the structure graphically, just hold down the H key and use the mousewheel to rotate your viewpoint horizontally, or hold down the V key and use the mousewheel to rotate your viewpoint vertically. Alternatively, you can rotate your viewpoint by clicking the "Viewpoint" from the View menu or the floating menu.


The current viewpoint setting is displayed near the top-right corner of the graphics display area together with a small set of axes. You can watch the axes move as you change the viewpoint or, by activating real-time structure rotation, you can also watch the entire structure rotating as you change the viewpoint. There are a number of ways to change the viewpoint as explained as follows. 1. Clicking the arrow buttons above the side toolbar buttons (as follows) allows you to change the viewpoint quickly without having to first click on any other buttons. After reaching the desired viewpoint, pick a point anywhere inside the graphics display area to cause a redraw at the new viewpoint.

468

Graphical Input

2. Choosing "Viewpoint-View real-time" from the View menu or the floating menu allows you to rotate the entire structure on the screen using the keyboard arrow keys. After reaching the desired viewpoint, pick a point anywhere inside the graphics display area to cause a redraw at the new viewpoint. 3. Choosing one of the "View front/View plan/View (30,10)/etc." items after clicking the "Viewpoint" toolbar button or from the "Viewpoint" item of the View menu or the floating menu causes the structure to be immediately redrawn at the new viewpoint. The "(30,10)" item corresponds to a horizontal angle of 30 and a vertical angle of 10. It is a useful viewpoint for 3D structures. 4. Choosing "Select" after clicking the "Viewpoint" toolbar button or from the "Viewpoint" item of the View menu or the floating menu causes the following form to appear.

You can change the viewpoint by editing the "Horizontal angle" and "Vertical angle" text boxes directly, or you can click on one of the arrow buttons at the bottom-left corner of the form. When using the arrow buttons, the amount by which the viewpoint changes can be controlled by setting the value in the "Angle increment" field. Alternatively, you can click on one of the seven plane buttons which take you immediately to a front, plan, left, (30,10), right, back or bottom viewpoint. SPACE GASS normally assumes that the global Y-axis is vertical when displaying the structure graphically, however the viewpoint form allows you to change the vertical axis to one of the other global axes.

469


The viewpoint settings (including the "Vertical axis" setting) only affect the graphics display. They don’t affect the local axis definitions, the steel design top flange definitions, or the analysis and design modules in any way.

470

Graphical Input

Views This tool lets you save everything about the current graphics display including its load case selections, filter selection, viewpoint, and any diagrams or node, member or plate properties that might be shown. The renderer version This is fully explained in View manager.

The traditional graphics window version To save the current display as a view or to manage the currently saved views, click the toolbar button or select "Views" from the View menu or the floating menu. You must then select "Save the Current View" from the floating menu that appears.

To save the current view, just click the combo box in the above form, select a view number and then type in the view’s name. You can overwrite previously saved views or you can select and name an unused view. You can save up to 100 different views. To manage (delete, renumber or rename) previously saved views, click the toolbar button or select "Views" from the View menu or the floating menu. You must then select "Manage the Saved Views" from the floating menu that appears.

471

SPACE GASS 12 User Manual To delete, renumber or rename any of the previously saved views, click the desired view in the datasheet shown above and then delete or edit it as required. To select and activate a view, click the "Views" toolbar combo box and make your selection. Scrolling through the saved views can be most conveniently done using the keyboard Shift+Ctrl+Page keys as described in Shortcuts.

472

Graphical Input

Zoom The Zoom tool allows you to zoom in or out on the entire structure or just a part of it. The renderer version You can zoom, pan or rotate your model via the mouse scrollwheel or by dragging it around using the left or right mouse buttons as shown below. Alternatively, you can press the right arrow key to "Zoom full" or the left arrow key to "Zoom previous". You can also zoom in on a selection of nodes, members or plates by selecting the desired items, right-clicking and then selecting "Zoom Selected" from the menu that appears.

The traditional graphics window version Zooming can be most conveniently done using the mousewheel or keyboard arrow keys as described in "Shortcuts". For example, while viewing the structure graphically, just use the mousewheel to zoom in or out. Alternatively, you can zoom by clicking the button or selecting "Zoom" from the View menu or the floating menu.

toolbar

There are four zoom modes as follows. 1. ZOOM full - redraws the entire structure at a scale that allows it to fit comfortably on the screen. 2. ZOOM window - requires you to place a window around a portion of the structure which it then enlarges and redraws to fill the screen. 3. ZOOM in/out - requires you to position the graphics cursor at the zoom centre and then click the left mouse button to ZOOM in or the right mouse button to ZOOM out. 4. ZOOM previous - reverts back to the previously displayed view. If you have selected ZOOM Window, you can revert to ZOOM Full or ZOOM Previous by pressing the keyboard F or P keys while selecting the window.

473

Analysis Analysis SPACE GASS uses the well documented stiffness method combined with a wavefront equation solver to model the elastic behaviour of structures. It is capable of performing five types of analysis, as follows.     

Linear (1st order) static analysis Non-linear (2nd order) static analysis Buckling analysis Dynamic frequency analysis Dynamic spectral response analysis

The SPACE GASS analysis modules can accurately deal with semi-rigid joints, elastic supports, master-slave constraints, offsets, tension/compression-only members, and cable members (static and buckling analysis only). Although the wavefront method is not highly sensitive to badly numbered structures, a wavefront optimizer which automatically minimizes the frontwidth is also available with SPACE GASS. The wavefront optimizer means that both the node, member and plate numbering sequences are incidental to the program. SPACE GASS has been dimensioned dynamically. This means that during the analysis phase SPACE GASS automatically adjusts its memory requirements according to the size of the job. If the available memory in your computer is enough to solve the structure entirely in memory then the analysis phase will be extremely fast. If you run out of memory during an analysis then some of the analysis data will be automatically written to disk and the analysis phase will not be quite as fast. You should aim to have as much of the data as possible held in memory during the analysis by minimizing the frontwidth or by increasing the memory capacity of your computer.

475


Static analysis Static analysis The SPACE GASS static analysis module is capable of performing linear or non-linear analyses. Furthermore, you can analyse some load cases linearly and others non-linearly in the same model. For non-linear analysis, SPACE GASS offers a choice of small, finite or large displacement theories in its non-linear static analysis solver. For cable members, SPACE GASS always uses a large displacement theory that has been designed to cope with the highly non-linear behaviour and large deflections that occur within cables (see also Cable members). For structures that contain both cables and non-cable members, it is important to note that while the large local cable deflections are allowed for in the analysis, the non-cable parts of the structure are still analysed using small displacement theory. The plates in SPACE GASS are linear elements only and therefore no P- or P- effects are considered for them during a non-linear analysis. Although a SPACE GASS non-linear static analysis includes simple buckling checks on individual members and on the frame as a whole, a full buckling analysis is usually required in addition to the static analysis. If the buckling capacity of the frame has been exceeded then the static analysis results are invalid and should not used!

If the static analysis results are to be used for a steel design to AISC-LRFD, Eurocode 3, AS4100 or NZS3404, the load cases used in the strength design must be analysed nonlinearly unless you know that the second order effects are negligible. The non-linear static analysis facility available with SPACE GASS considers geometric nonlinearities rather than material non-linearities. Material non-linearities occur as a result of the non-linear stress-strain relationship of most materials. This effect becomes more significant as the material reaches its yield point and the stress-strain curve flattens out. SPACE GASS does not consider material non-linearities because they are relatively insignificant in comparison with geometric non-linearities and because their effect only becomes noticeable when the material is highly stressed. There are many types of geometric non-linearities, some of which can be significant and many of which are relatively insignificant. The most important geometric non-linearities are:     

P- effect P- effect Axial shortening effect Tension/compression-only effect Catenary cable effect

Some sources refer to the additional effects of shear deformations and rigid end gussets as being geometric non-linearities also. While SPACE GASS fully considers these additional effects during the analysis phase, it does not consider them to be non-linearities because they can be solved directly in one analysis and do not require an iterative procedure. 476

Analysis

Because the plates in SPACE GASS are linear elements only, no P- or P- effects are considered for them during a non-linear analysis.

477


Displacements, actions and reactions During the static analysis phase, there are three basic groups of data that have to be calculated. They are node displacements, member and plate actions (forces and moments) and support reactions. Node displacements Node displacements are calculated for each load case being analysed and for every unrestrained degree of freedom in the structure. Each node may translate along or rotate about any or all of the three global axis directions. Restrained (fixed or deleted) degrees of freedom are automatically assigned displacements of zero except for those nodes that have prescribed displacements specified. In such cases those nodes are assigned the prescribed displacement only for the particular load case in which they were specified. Member actions There are twelve forces and moments that can be calculated for each member. Each end of a member is subjected to an axial force, a torsion, bending moments about its y and z axes and shear forces along its y and z axes. The program is also capable of calculating forces and moments at user defined intermediate points along members. These intermediate values, however are not calculated during the analysis phase. Instead they are calculated as required when the output report is produced. For more information, refer to Sign conventions. Plate actions Three forces and three moments are calculated for each plate node, making a total of 18 actions per triangular plate and 24 actions per quadrilateral plate. Two axial stresses, three shear stresses and three bending stresses are also calculated for each plate. These are later used to calculate the 17 different force, moment and stress values for each plate that can be shown graphically as colored contours or included in text reports. For more information, refer to Sign conventions. Reactions External node reactions are the forces and moments exerted by the structure on the supports. They are calculated only for restrained nodes and are referenced by the global axes system.

478

Analysis

P-D effect The P- effect occurs as a result of the ends of an axially loaded member moving laterally with respect to each other. A moment of P. is induced which alters the member’s equilibrium and causes the relative member end movement to change further.

P- effect

Unless the axial load P exceeds the member’s critical buckling load, a point of equilibrium eventually occurs such that the P- moment is balanced by moments applied by other members or restraints. The P- effect is not considered for plate elements.

479


P-d effect The P- effect occurs as a result of lateral curvature being induced in an axially loaded member. A parabolic moment distribution is induced along the length of the member which alters the member’s effective stiffness and causes the curvature to change further.

P- effect

Unless the axial load P exceeds the member’s critical buckling load, a point of equilibrium eventually occurs such that the P- moments are balanced by internal flexural resistance built up within the member. The P- effect is not considered for plate elements.

480

Analysis

Tension-only and compression-only effects While in tension, tension-only members act identically to normal members with axial, flexural, torsional and shear capacity. However, if they go into compression then they are automatically disabled and act as if they have been removed from the model. Similarly, compression-only members act identically to normal members unless they are disabled as a result of going into tension. Although the solution of tension-only or compression-only members requires an iterative analysis method, SPACE GASS puts it into a slightly different category to the other nonlinear effects and makes it available in either a linear or a non-linear static analysis. Unlike the P- and P- effects, tension-only and compression-only effects result in an exact solution provided that convergence can be achieved. For tension/compression-only effects, convergence is sometimes difficult (if not impossible), especially if the frame is highly symmetrical. If convergence is not achieved after three iterations, SPACE GASS relaxes the tension/compression-only criteria slightly in an attempt to improve the chances of reaching convergence. During the first three iterations SPACE GASS disables tension-only members which have either end in compression. During iterations four and five it disables tension-only members which have the average of their end forces in compression. During the sixth and further iterations it disables tension-only members which have both ends in compression. A similar procedure is followed for compression-only members which have tensile forces at their ends. If tension/compression-only effects have been activated with "No reversal" then convergence is usually achieved after two or three iterations, even for highly symmetrical structures. This "No reversal" method is not usually recommended, however because it sometimes results in members being prematurely disabled and then not being able to be re-enabled in later iterations after the axial forces have been redistributed around the frame.

Tension/compression-only effects are ignored by the dynamic frequency analysis module. No tension-only or compression-only members are disabled in a dynamic frequency analysis, regardless of their axial force. ! IMPORTANT NOTE ! Tension-only members should not be used to model cables. See also Members.

481


Cable members The analysis of cable members requires special treatment because of their pure axial capacity, large displacements and highly non-linear behaviour. Cable members never actually go into compression, they simply sag or change their shape so that they are in equilibrium at all times. They have no flexural, torsional or shear capacity, and resist lateral loads by tension alone. Cable loading Cable members can be loaded with UDLs, thermal loads, prestress loads and self weight. For "Local" or "Global projected" UDLs, the total load is equal to the load per unit length multiplied by the actual (for "Local") or projected (for "Global projected") distance between the end nodes. For "Global inclined" UDLs, the total load is equal to the load per unit length multiplied by the unstrained cable length. Cables must be loaded with at least one uniformly distributed load (self weight will do) in every load case they are analysed for. If there is no UDL on a cable, SPACE GASS will apply an artificial lateral UDL equal to one-tenth of the self-weight of the cable. While this adds a non-existent load to the model, it is not likely to affect the results significantly due to the small magnitude of the load. Note that the procedure of converting cables without UDLs to tension-only members in SPACE GASS 9.03 and earlier versions is no longer done. Restraining nodes connected to cables Cable members have zero moment capacity and must be assumed to be pin-ended even if the end fixities are input as FFFFFF. This would normally cause rotational instabilities in the nodes that are connected only to cables, however SPACE GASS recognises this and automatically restrains these rotations if instabilities would occur. Cable convergence Convergence is often a problem for structures which contain cables because of their large deflections and highly non-linear behaviour. There are four recognized methods for obtaining convergence. 1. 2. 3. 4.

One load step, many iterations, no damping. One load step, many iterations, deflection related damping. One load step, many iterations, damping with uniform relaxation. Many load steps, one iteration per load step, no damping.

All four methods give the same results for the same final convergence. Methods 1 and 2 are generally the fastest but they don’t achieve convergence in all structures, especially flexible structures. Methods 3 and 4 are more likely to achieve convergence but sometimes require more iterations. For methods 3 and 4, the number of iterations required is pre-defined by the number of relaxation steps or load steps that you specify at the start of the analysis. For each method, but methods 3 and 4 in particular, it is generally apparent after only a few iterations whether convergence is going to be achieved or not. If the convergence level is not steadily creeping upwards or has not reached about 60% or 70% by 5 or 6 iterations then it is unlikely that convergence will be achieved. If this happens, it is generally best to stop the analysis and then start it again with a different method, or change the damping, or increase the number of load steps. For example, using method 4, it is quite feasible that 50 load steps will converge where 40 load steps will not. 482

Analysis

If you lower the convergence accuracy, the analysis may not converge sufficiently and you risk getting incorrect results. It is particularly important that you don’t lower the convergence accuracy for highly non-linear structures such as those that contain cables. Cable prestress The prestress load you apply to a cable is not likely to be the final axial force in the cable at the end of the analysis. This is because the axial force changes as the cable stretches or sags as its end nodes move. If you wish to achieve a particular axial force at the end of the analysis then a trial and error process is required. This involves setting an initial prestress force, performing the analysis, checking the final axial force, adjusting the prestress and repeating the process until the desired axial force is achieved. This is a common requirement in posttensioned concrete applications where the tendons are jacked to a known tension. In some instances, you may wish to apply a prestress load to a cable member instead of specifying a non-zero unstrained cable length. The prestress load P that is equivalent to an unstrained cable length L is given by the equation:

where

D = chord length, A = cross sectional area, E = Young’s modulus of elasticity.

! IMPORTANT NOTE ! If cable members exist in your structure, it is imperative that you specify them as "Cable" members in your SPACE GASS model. If you try to model them as "Normal" or "Tensiononly" members, the results will be incorrect. See also Members. See also Thermal loads.

483


Non-linear analysis procedure The procedure that SPACE GASS adopts to perform a non-linear static analysis is as follows. 1. An initial linear static analysis is performed. 2. For each element in each load case, a modified stiffness matrix is assembled. For non-cable members, the modified stiffness is based on the deformation of the structure and the member axial forces calculated in the previous analysis iteration. The modifications to the stiffness matrix are in accordance with the theory presented by Ghali and Neville (2) for small displacement theory or the theory presented by Hancock (24) for finite and large displacement theory. They involve changes to the axial and flexural stiffness terms, taking into account P- P- and axial shortening effects (if activated). For cable members, the modified stiffness is based on the unstrained cable length, the cable lateral loads and the deflected position of the cable ends calculated in the previous analysis iteration. For plate elements, the stiffness matrix is unchanged. 3. If P- effects are turned on with finite or large displacement theory, the non-cable member fixed end actions are adjusted for the deformation of the structure. 4. If P- effects are turned on, the non-cable member fixed end actions are adjusted for the change in flexural stiffness of the member. 5. The frame is re-analysed with the modified member stiffness matrices. In this and later analysis iterations, each load case must be solved separately because the structure stiffness matrix is now different for each load case. This can take considerably longer than the initial linear analysis, especially if there are numerous load cases. 6. The results of the latest analysis are compared with the previous analysis and the level of convergence is displayed on the screen. If the level of convergence has reached the requested convergence accuracy then the results have converged and the analysis terminates. If not, steps 2 and 3 are repeated for the unconverged load cases until a solution is reached. If some load cases have still not converged after the specified number of iterations per load step then the program pauses and asks if further iterations are required. If no further iterations are requested, the analysis terminates and the results for the converged load cases only are saved.

Because the plates in SPACE GASS are linear elements, no P- or P- effects are considered for them during a non-linear analysis.

484

Analysis

Static analysis buckling Although a SPACE GASS non-linear static analysis does not perform a full buckling analysis, it does include some buckling checks as described below. For details of the capabilities of a full buckling analysis, refer to Buckling analysis. 1.

The SPACE GASS non-linear static analysis includes a simple buckling check on individual members that is intended to alert you if a member is being removed from the model due to its Euler buckling load being exceeded. However, it is not a full buckling check that considers groups of members or the structure as a whole. A common misconception appears to be that if the static analysis passes this simple single member buckling check then buckling is not a problem. Another misconception is that if the simple buckling check fails, you can just subdivide the buckled member until the error goes away and everything will be Ok. Clearly, this doesn't fix the problem, it just transfers the buckling from a single member mode to a multi-member mode that is no longer detected by the single member buckling check. The only way to be sure that buckling is not a problem is to perform a full buckling analysis.

2.

The SPACE GASS non-linear static analysis also includes a frame buckling check that simply alerts you if the structure's buckling capacity has been exceeded. This will allow you to determine if the static analysis results are reliable or not, and nothing more. It will not calculate member effective lengths or the buckling load factor, and hence will not be able to alert you if buckling is close to happening. Consequently, a full buckling analysis will still be required for most structures.

It is very important to note that the results of a static analysis will be incorrect if the structure's buckling capacity has been exceeded, and hence one of the key roles of a buckling analysis is to ratify the static analysis results. Although most practical structures do not come close to reaching their buckling load, unless you know that your frame has not reached its buckling load, you should perform a buckling analysis.

Because the plates in SPACE GASS are linear elements, they will not buckle regardless of the load applied. See also Buckling analysis.

485


The wavefront optimizer The SPACE GASS wavefront optimizer temporarily re-organises the structure during the analysis phase to achieve close to the smallest possible frontwidth with the fastest possible analysis time. The basic philosophy behind the optimizer is quite simple. It alters the order in which members and plates are loaded into the stiffness array by starting at one end of the structure and proceeding through it to the other end in one complete pass. Depending on the operating mode selected, the optimization can follow an irregular path, a straight line path or a circular path. The optimizer usually reduces the frontwidth to within 95% of the optimum, however some structures such as large cubes which do not have a well defined "long dimension" can reduce its efficiency to almost 60%. Large cubic structures therefore may require careful member and/or plate numbering if they produce excessively large frontwidths. If you have already numbered the members and plates to achieve the smallest possible frontwidth then the optimizer will of course not have much effect. If, however you have numbered the elements badly, the optimizer will probably have a dramatic effect. The most noticeable effect will be the smaller analysis time which is partly proportional to the frontwidth squared. You can control the direction along which the optimization proceeds by selecting the optimization mode at the start of the analysis. The various optimization mode settings are described in the following sections. Not activated If the optimizer is not activated, the members and plates are loaded into the stiffness array in the order that they are numbered. If they have been badly numbered and the structure is large then excessive analysis times may result. Auto mode SPACE GASS trials the "General" and various "Linear" modes and then uses the one that gives the smallest frontwidth. It doesn't add significant time to the analysis and is the recommended setting. General mode SPACE GASS starts at the lowest numbered member or plate and then loads all of the elements that are connected directly to it. It then takes each of the connected elements in turn and loads all of the elements that are connected to them. This process continues until all elements in the structure have been loaded. This mode results in very efficient frontwidths for most structures. Linear mode This mode instructs the optimizer to proceed through the structure in a straight line direction parallel to one of the global X, Y or Z axes or along a vector that you specify. After you have specified linear mode, you must also nominate the axis or vector along which optimization will proceed. This should generally be in the direction of the long dimension of the structure. Linear mode is ideally suited to long thin structures which have a well defined long dimension. The "long dimension" of a structure is not necessarily the dimension with the greatest length, rather it is defined such that if you make a cut through the structure at right

486

Analysis angles to the long dimension at its widest point, you will cut through the least number of elements. In the truss in the following diagram, the most efficient direction for the optimizer to proceed is horizontally. This is because a cut at right angles to the horizontal cuts through only four members.

Horizontal optimization

Vertical optimization

In the 2D multi-storey frame above, the most efficient direction for linear optimization is vertical even though the frame height is less than the frame width. Circular mode This mode instructs the optimizer to proceed through the structure around an arc with the axis of rotation parallel to one of the global X, Y or Z axes. After you have specified circular mode, you must also nominate the axis about which optimization will proceed, followed by the coordinates for the centre of rotation. Circular mode is ideally suited to curved structures such as the circular frame shown following. Structures which are not perfectly circular but which have a general shape which is arranged around a central point can also be optimized very efficiently using circular mode. The centre of rotation should generally be near the centre of the structure, however this is not absolutely essential.

487


Circular optimization

Circular mode can also be used to great advantage with structures that require linear optimization in two directions. A three dimensional multi-storey frame for example would probably require its primary optimization direction to be vertical. As the optimizer reached each floor, however a secondary horizontal direction would also need to be specified otherwise it would not know in which direction to go along the floor. Without a secondary direction, the optimizer would simply have to load the floor elements in the order of their numbering and this could result in an unnecessarily large frontwidth if the elements were badly numbered. It is not possible to specify a primary and secondary direction with the optimizer in linear mode, however it is possible to do this in circular mode by having the centre of rotation a large distance away from the structure. Using circular mode in this way is very similar to linear mode except that as the optimizer progresses across (or up) the structure, the angle of attack also changes slightly as it moves around the arc.

488

Analysis

Bi-directional optimization

Consider for example the three dimensional multi-storey frame shown above. The primary optimization direction is vertical and the secondary direction for each floor is to the left. By using circular mode and positioning the centre of rotation at a large distance away from the frame as shown in the following diagram, the desired result can be achieved.

Bi-directional optimization using circular mode

489

SPACE GASS 12 User Manual As the optimization line progresses up the structure, it reaches the right hand side of each floor before the left hand side. Thus, the structure as a whole is optimized from bottom to top and each floor is optimized from right to left. Note that this method of optimization is usually the best way to deal with large cubic shaped structures. If you are not sure which optimizer mode to use for a particular structure, it is recommended that you experiment with various modes to see how small a frontwidth can be achieved. You can do this by running the analysis and then terminating it by pressing ESC or the right mouse button after the frontwidth has been calculated and displayed on the screen. Once you have found the most efficient mode, you can simply let the analysis continue to the end as normal.

490

Analysis

The wavefront analysis method Conventional structural analysis programs utilizing the stiffness method generally use a bandwidth equation solver which requires that nodes be numbered correctly to ensure the smallest possible bandwidth. The wavefront method, however requires that the members and plates be numbered correctly to ensure the smallest possible frontwidth. The optimum wavefront numbering sequence, however is quite logical and is not sensitive to adding more nodes, members and plates at a later stage which are out of sequence. This can be quite a problem with the bandwidth method. For most structures, the element numbering sequence doesn’t matter because the frontwidth capacity of SPACE GASS is quite large. Large structures, however can be made to analyse faster by optimizing the frontwidth. The displacements calculation time is roughly proportional to the square of the frontwidth. A wavefront optimizer is available with SPACE GASS which internally re-orders the stiffness matrix and which generally reduces the frontwidth to within 95% of the optimum. The optimizer adds only a few seconds to the analysis time and gives you the freedom of not having to concern yourself with element numbering sequences even for the largest structures. For those of you who are interested in the wavefront solution method, the following sections should give you an insight into the inner workings of the SPACE GASS analysis module.

491


A quick frontwidth calculation method In order to minimize the frontwidth, members and plates should be numbered from side to side across the structure’s shortest dimension while gradually proceeding up the length of the structure. The numbering should proceed up the entire length of the structure in one pass. A tall multistorey building for example would have the ground floor columns numbered first, followed by first floor beams, first floor columns, second floor beams, second floor columns etc., right up to the top. A quick frontwidth calculation can be done as follows. 1.

This procedure assumes that the element numbering sequence proceeds generally from one end of the structure to the other in a single pass as described in the paragraph above.

2.

Make an imaginary cut through the structure at its widest point and at right angles to the general direction of element numbering. For example, the multistorey frame described above would have a horizontal cut at any one of its levels.

3.

On one side of the cut only, count the number of nodes that are connected to elements that have been cut.

4.

Add 1 to the number of nodes in step 3 above and multiply by the degrees of freedom (DOF) per node. For 3D frames this will generally be 6 DOF per node.

5.

Subtract the number of restrained DOF (ie. the restraints applied to the nodes counted in step 3).

The final figure is the structure frontwidth. It is generally not necessary for you to know any more about the wavefront method than has been described above, however for those of you wishing to know more, a detailed explanation of the wavefront analysis method follows.

492

Analysis

The wavefront method in more detail Both the bandwidth and wavefront methods are primarily concerned with the assemblage and solution of a very large structure stiffness array. This array equates node displacements to externally applied loads as follows. [P]=[K][D], where

[P] = Load array [K] = Structure stiffness array [D] = Node displacement array

[P] and [K] are fully defined while [D] is the unknown. The wavefront method is different to the bandwidth method in that the structure stiffness array is assembled in order of element numbering rather than node numbering, and a much smaller portion of the array is required in memory at any one time. In the wavefront method, the program loads each element into the stiffness array in order of the element numbering sequence. The nodes associated with each element have stiffness equations that occupy certain rows and columns in the array. This loading process continues until one or more nodes have been fully assembled. A node is said to be fully assembled when all elements connected to it have been loaded into the array. At this point the equations associated with that node can be solved and removed, thus leaving space in the array for other nodes. Further elements are then loaded and their nodes take the place of nodes that have previously been solved and removed. More node equations are eliminated and the whole process continues until the entire structure has been fed in and the stiffness array emptied. The frontwidth is equal to the largest number of node equations that occupied the stiffness array at one time.

493


Running a static analysis You can run a static analysis by selecting "Linear Static Analysis" or "Non-linear Static Analysis" from the Analysis menu or you can change from linear to non-linear or vice-versa using the Type analysis parameter in the form shown below.

Load case list If you want to analyse all load cases then this field can be left blank, otherwise you should type in a list of load cases (separated by commas or dashes) that you want analysed. For the fastest analysis time you should generally analyse only the load cases that can occur in reality. For example, there is no point in analysing a live load case on its own because it can't occur in real life without being combined with dead load. This means that you should generally analyse just the combination load cases and not the primary load cases that the combinations are made from. It is sometimes also possible to achieve time savings by analysing non-linearly only those load cases that cause 2nd order effects, and analysing all of the other load cases linearly. This would have to be done in two runs, however because a non-linear analysis can take considerably longer than a linear analysis (especially if there are a large number of load cases), it is often worthwhile. Further time savings can be made by not analysing linear combination load cases. "Linear combination load cases" are combinations that have all of their primary load cases analysed linearly. Results for non-analysed linear combinations are assembled from the primary load cases at the time a report or graphics output is generated. If a combination load case has one or more of its primary load cases analysed non-linearly or if the structure contains tensiononly or compression-only members then the combination will have to be analysed in order to obtain results for it. When specifying the load case list, you can either list them directly, or you can click the button to display and select from a list of the load cases currently in the job as shown below. 494

Analysis

Tension/Comp-only effects Tension/compression-only effects can be "fully operational", "operational with no reversal" or "fully de-activated". "Fully operational" means that tension-only or compression-only members which have been disabled during the analysis are able to be re-enabled if their axial force is reversed. "Operational with no reversal" means that once they have been disabled they cannot be reenabled even if their axial force has reversed. No reversal is useful if the fully operational analysis will not converge, however you should check the results and, if required, manually disable some tens/comp-only members and then re-analyse. No reversal normally applies from the first iteration onwards, however you also have the option of activating it after a specified number of iterations. This means that the analysis will initially proceed with tension/compression-only effects fully activated and, if convergence hasn’t been achieved after a specified number iterations, it will change to "no reversal" mode. "Fully de-activated" means that they are treated as normal members, able to take tension and compression. See also Tension-only and compression-only effects. Cable damping factor This allows you to apply damping to the cable connected nodes. It does this by multiplying the stiffness terms of the unrestrained cable-only node degrees of freedom by the factor:

where Ratio depends on the damping relaxation and Damping is the cable damping factor. See also Cable members.

495

SPACE GASS 12 User Manual Damping relaxation steps If cable damping is used, it must be relaxed as the solution proceeds so that at convergence there is no damping at all. Setting the damping relaxation steps to zero causes the damping to be relaxed in direct proportion to the change in deflection between the current and previous iterations. As convergence approaches 100%, the change in deflections approaches zero and hence the damping approaches zero. Alternatively, setting the damping relaxation steps to a finite value causes the damping to be relaxed in uniform steps down to zero. If this method is used, the analysis keeps iterating until the damping is fully relaxed, regardless of whether convergence has been achieved earlier or not. See also Cable members. Number of load steps This allows you to apply the load gradually in a number of small load steps. If you specify a single load step then all of the load is applied in the first iteration (this is how the program worked in all previous versions). If cable damping is also being used, the damping relaxation process begins anew for each load step. See also Cable members. Iterations per load step This parameter allows you to specify the maximum number of iterations that will occur in a load step before the program begins prompting you for extra iterations. A special case occurs if you specify just one iteration per load step, in which case the program proceeds to the next load step after one iteration regardless of whether convergence has been achieved or not.

The analysis will finish if the convergence accuracy is satisfied, even if the number of iterations per load step hasn’t been completed. Convergence accuracy (%) The convergence accuracy is only applicable for non-linear analyses. After each iteration, SPACE GASS compares the results of the latest analysis with the results of the previous analysis. If the comparison shows that the level of convergence has reached or exceeded the specified convergence accuracy then the analysis is assumed to have converged. If you lower the convergence accuracy, the analysis may not converge sufficiently and you risk getting incorrect results. It is particularly important that you don’t lower the convergence accuracy for highly non-linear structures such as those that contain cables. Retain results of other load cases If you have specified that not all load cases are to be analysed and, if results already exist for some of the non-specified load cases, you can choose to retain them or have them deleted. Show messages from single member buckling check During a non-linear analysis, SPACE GASS performs a simple Euler buckling check on each member individually (regardless of whether you have the buckling analysis module or not). If the buckling check fails then the member is disabled for the remainder of the analysis. If you select the "Show messages from single member buckling check" check box then a message is

496

Analysis displayed whenever a member fails the simple buckling check. For more information, refer to Static analysis buckling. Perform frame buckling check SPACE GASS can optionally perform a frame buckling check during a non-linear analysis that simply alerts you if the structure's buckling capacity has been exceeded. If this happens, you cannot use the results of the static analysis because they will most likely be invalid and you should run a full buckling analysis to get the buckling load factor and find out where the buckling is occurring. For more information, refer to Static analysis buckling and Buckling analysis. Check for non-existent load cases If you have defined combination load cases that contain other load cases which don’t yet exist, this option will detect and report them. It is optional because some users prefer to have a standard set of combination load cases that contain primary load cases which are just ignored during the analysis if they don’t exist. Stabilize unrestrained nodes Nodes that are free to rotate or translate in one or more directions without resistance from interconnecting members, plates, restraints or constraints can be automatically restrained during the analysis so that instabilities don’t occur. For example, if a node was connected to a number of members, all of which were pin-ended, a rotational instability would normally result due to the unrestrained rotation of the node. However, the stabilize option would apply a temporary rotational restraint to the node during the analysis, preventing an instability. Although this solves many instabilities, it doesn’t fix them all, and the prevention of nontrivial instabilities is still dependent on good modelling practice. Rotate local loads with member chord rotation If this option is ticked then after the first analysis iteration any local member loads will be rotated with the chord rotation of the members to which they are applied. It can be used to ensure that wind loads or hydrostatic loads remain normal to the member direction as the model deforms. This option is only enabled with finite or large displacement theory in a nonlinear analysis. Type Even though you have already chosen "Linear" or "Non-linear" from the Analysis menu, this pair of radio buttons allows you to change your mind without having to exit the form. A linear analysis generally involves only one iteration and does not adjust the stiffness of the structure based on its deformation. It is suitable for simple beams or fully braced frames, but not for sway frames or flexible structures in which non-linear effects are significant. A non-linear analysis involves an iterative procedure that updates the stiffness of the structure after each iteration and gives more realistic results than a linear analysis. Solver The "Paradise" solver is a new parallel multi-core sparse solver that fully utilizes the multiple cores in a modern computer's CPU. All of the available cores are run in parallel to get the maximum possible analysis speed. It also takes full advantage of the sparseness of the structural matrix during the solution to minimize memory requirements and further increase the speed. The Paradise solver is the recommended setting for all static analyses.

497

SPACE GASS 12 User Manual The "Wavefront" solver also takes into account the sparseness of the matrix but doesn't run in multi-core mode. It is generally slower than the Paradise solver and can be used if the Paradise solver is unable to obtain a solution. The "Watcom" solver is the one used in pre-SPACE GASS 12 versions. It is considerably slower than the Paradise and Wavefront solvers and is therefore of limited use. All three solvers should yield virtually identical results. Theory Small displacement theory (based on Ghali and Neville (2)) is the default setting and is suitable for most structures in which the members aren't subjected to significant chord rotations (changes in direction of members). Small displacement theory results are output in the undeformed axes system. The finite and large displacement theories (based on Hancock (24)) take member chord rotations into account and base their equilibrium equations on the deformed geometry. Finite and large displacement theory results are output in the deformed axes system. Large displacement theory uses more exact methods than finite theory when adjusting the stiffness matrix to allow for the deformation of the structure, however for many structures they yield very similar results. Note that although the finite and large displacement theories can handle larger displacements, it is often harder to achieve convergence with them than with small displacement theory, especially when large displacements occur. Matrix The main stiffness matrix can be a secant matrix (relating the full loads to the total displacements) or a tangent matrix (relating the residual loads to incremental displacements). A tangent matrix generally reaches convergence in a smaller number of iterations than a secant matrix and is more suited to large displacements, however this is not always the case. They both yield similar results. Note that small displacement theory always uses a secant matrix. Residual loads are the imbalance between the applied loads and the internal frame forces at each node. Incremental displacements are the difference in displacements between the current and the previous iteration. The residual loads and the incremental displacements both approach zero as the solution approaches convergence. Note that if you use a secant matrix with finite or large displacement theory and full loading, the stiffness matrix is non-symmetrical. This means that during the analysis, the stiffness matrix uses up twice as much memory as it otherwise would and so it should be avoided if your model is large. Loading For a secant matrix, you can choose between full or residual loading (see above), whereas the tangent matrix always uses residual loading. They both yield similar results, but if convergence is a problem then it may be worth experimenting with this setting. Convergence Convergence can be based on deflections or residuals or both and is achieved when they approach zero. It is recommended to have them both selected.

498

Analysis P-Delta (P- effect For a non-linear analysis, you are able to activate or de-activate P- effects. The P- effect is usually the most significant 2nd order effect and is mandatory for non-linear analyses which comply with most limit states design codes of practice. See also P-D effect. P-delta (P- effect For a non-linear analysis, you are able to activate or de-activate P- effects. The P- effect is mandatory for non-linear analyses which comply with most limit states design codes of practice. See also P-d effect. Axial shortening effect For a non-linear analysis, you are able to activate or de-activate axial shortening effects. The axial shortening effect models the effect of the "shortening" of the distance between the ends of a member due to its curvature. Axial shortening induces extra tension in a member that has a significant curvature. It is turned off by default and generally has a minimal effect on the analysis results. Optimization method The wavefront optimizer can be de-activated or it can be operated in one of four modes as follows. 1. No optimization 2. Auto mode - SPACE GASS trials the "General" and various "Linear" modes and then uses the one that gives the smallest frontwidth. It doesn't add significant time to the analysis and is the recommended setting. 3. General mode - SPACE GASS determines the path along which optimization proceeds through the structure. 4. Linear mode - You select from the X, Y or Z axes or a vector along which optimization proceeds in a straight line through the structure. 5. Circular mode - You select either of the X, Y or Z axes about which optimization proceeds around an arc through the structure. See also The wavefront optimizer. Optimization axis If you have selected "Linear" or "Circular" for the wavefront optimization mode then you must select the axis or vector along or about which optimization will proceed. See also The wavefront optimizer. Coordinates of optimization centre If you have selected "Circular" for the wavefront optimization mode then you must select the centre of rotation about which optimization will proceed. See also The wavefront optimizer.

When all of the information has been entered, the static analysis module calculates the displacements, forces, moments and reactions for each load case and then saves them ready for graphical or text report output.

499


If you want to terminate the analysis before it is finished, just press ESC or the right mouse button. If you terminate the analysis in this way, the results for any load cases which have already converged are saved. This applies to non-linear analyses and to linear analyses with tension-only or compression-only members.

500

Analysis

Static analysis results At the end of the static analysis, a message stating whether the analysis was successful or not is displayed together with a number of possible warnings and errors. Refer to "Ill-conditioning and instabilities" for details of what to do if an ill-conditioning or instability message is displayed. Refer to "Static analysis buckling" for details of what to do if a frame buckling message is displayed. Displacements, forces, moments and stresses The displacements, forces, moments and stresses calculated during the static analysis can be included in a report. They can also be viewed graphically in diagrams superimposed over the undeformed frame as described in "View diagrams". For plate elements, contour diagrams can be displayed as described in "View plate contours". You can also query individual nodes, members or plates graphically to find their displacements, forces and moments as described in "Query analysis results".

For full details of the forces, moments and stresses in members and plates, refer to "Sign conventions". Bill of materials A bill of materials report showing quantities, lengths and masses of each type of component in the structure can be included in a report. It bundles members of the same type and length together and shows their individual and total lengths and masses. It also shows the total structure mass and centre of gravity location. Centre of gravity The SPACE GASS bill of materials report includes the coordinates of the structure centre of gravity.

501


Buckling analysis Buckling analysis The SPACE GASS buckling analysis module performs a rational elastic buckling analysis of a frame to determine its buckling load factors, buckling mode shapes and member effective lengths. The buckling load factor is the factor by which the loads need to be increased to reach the buckling load. A load factor less than 1.0 means that the working loads exceed the structure’s buckling capacity. For information about displaying buckling mode shapes and finding out where buckling is occurring, refer to "Buckling analysis results". The buckling modes considered in the buckling analysis involve flexural instability due to axial compression in the members (also known Euler buckling) and should not be confused with flexural-torsional buckling (torsional instability due to bending moments) or axialtorsional buckling (torsional instability due to axial loads). An accurate buckling analysis such as the one available in SPACE GASS looks at the interaction of every member in the structure and detects buckling modes that involve one member, groups of members, or the structure as a whole. A buckling analysis is an essential component of every structural design because it: 1.

Determines if the loads exceed the structure's buckling capacity and by how much.

2.

Calculates the member effective lengths for use in the member design.

3.

Determines if the static analysis results are useable or not.

Points 1 and 3 above highlight the fact that a buckling analysis must always be performed unless you are certain that the structure's buckling capacity exceeds the applied loads by a suitable factor of safety. Important points 1. The results of a static analysis will be incorrect if the structure's buckling capacity has been exceeded (see point 3 above), and hence one of the key roles of a buckling analysis is to ratify the static analysis results. 2. If you get buckling load factors that are below the minimum allowable value (eg. shown as "<0.001" when the minimum allowable value is 0.001), this could indicate an instability problem rather than a buckling problem. It is even more likely to be an instability problem if the low buckling load factors occur in every load case. 3. If the model contains instabilities, the buckling analysis may, in some cases, give invalid results. In the absence of instability or buckling messages from the static analysis, you should always check the deflections to see if they are excessive or not. Excessive deflections are sometimes the only indicator of instabilities. 4. Spectral load cases are not included in a buckling analysis. Furthermore, if you perform a buckling analysis on a combination load case that contains spectral load 502

Analysis cases, only the non-spectral load cases in that combination will be considered. This means that if you transfer member compression effective lengths from a buckling analysis into a steel member design, any spectral load cases considered in the design will not be involved in the calculation of the effective lengths. 5. Because plate elements are linear elements only, they will not fail during a buckling analysis regardless of the magnitude of the applied load. This means that their capacity and restraining effect on other members may be overestimated during a buckling analysis.

Once the buckling load factors have been determined, a simple formula is used to calculate the member effective lengths as described in the next section. The effective lengths can then be automatically transferred into the steel member design modules. The method that SPACE GASS uses to calculate the buckling factors (eigenvalues) and corresponding mode shapes (eigenvectors) is based on the theory developed by Wittrick and Williams (12). Note that the magnitudes of the effective lengths or the effective length factors (k factors) from a buckling analysis cannot be used to determine if buckling is a problem or not. This can only be determined by looking at the buckling load factor. Refer to "Static analysis buckling" for details of some simple buckling checks that are included in non-linear static analyses. Refer to "Special buckling considerations" for details of items to be aware of when preparing your model for a buckling analysis. Refer to "Buckling analysis results" for details and interpretation of the results of a buckling analysis.

503


Buckling effective lengths The effective length of a compression member is the length of an equivalent pin-ended strut that has an Euler buckling capacity equal to the axial force Pcr in the member at the point of frame buckling. It can be determined from:

It is evident from the formula that because the member actual length is not involved in the calculation, subdividing the member into smaller segments does not change its effective length. Thus, the effective length of a strut is the same as the effective length of one of its segments if it has been subdivided. Effective lengths calculated by the buckling analysis can be automatically transferred into the steel member design modules. This has the obvious advantage that effective lengths don't have to be transferred manually, but it also offers design efficiencies in that the effective lengths will be calculated specifically for each design load case rather than having to use one set of effective lengths for all load cases. If you are manually specifying the compression effective lengths in the steel member design data rather than having them transferred automatically from the buckling analysis, for design groups that consist of a number of analysis members connected end-to-end, you should use the MAXIMUM (not the sum!) of its individual analysis member effective lengths. Overestimation of effective lengths Effective lengths from a buckling analysis are sometimes overestimated because the portion of the frame that buckles first determines the buckling load factor (BLF) and, consequently, controls the effective lengths of all the members in the frame. The buckled portion of the frame may just involve one or two members and may be remote from many of the members that are having their effective lengths controlled by it. For example, the buckling collapse of the left-hand column of a portal frame due to a heavy load applied to it can control the effective length of the right-hand column which has no such load applied. Consequently, each column would have a different effective length. It would be ideal if the buckling analysis could increase the BLF beyond the first buckling mode so that the effective length for each member could be based on a buckling mode that involved that member. Unfortunately, this is not often possible because once the frame has reached its first buckling mode, it has generally collapsed and cannot resist any increase in load. However, if the first buckling mode involves only minor members such as bracing or similar, rather than a collapse of the frame, it may be possible to continue the buckling analysis to a higher order buckling mode in order to get more realistic effective lengths. You can see from the above discussion that members which are lightly loaded at the point of frame buckling will get a long effective length because of their small Pcr (see the equation above). In some cases, this may result in conservative designs, however there are a few factors that can help as follows: 1.

504

Members that have long effective lengths are generally lightly loaded axially, and these two effects tend to cancel each other out during the design phase.

Analysis 2.

For codes such as AS4100 that don't require it, turn off the slenderness ratio check at the start of the design phase. This is often very effective because, in the slenderness ratio check, a long effective length does not benefit from being cancelled out by a small axial force.

3.

For sway members, you can limit the effective lengths to a multiple of the actual member length by entering a factor into the "compression effective length ratio limit" field at the start of the design phase. In fact, effective lengths charts in most design codes limit the effective lengths for sway members to not more than 5.0 times the actual member length.

4.

For braced members, you can simply specify them as "braced" in the steel member design data for the direction(s) in which they are braced. This will limit the effective lengths from the buckling analysis to the actual member length.

505


Special buckling considerations Although a buckling analysis requires no more input data than a standard static analysis, there are a number of items to be aware of when preparing a model for a buckling analysis. Restraining the structure for buckling It is important that you restrain the appropriate degrees of freedom to prevent buckling modes that can’t occur in the real structure. For example, if a plane frame is braced in the out-ofplane direction, you must ensure that the braced nodes are restrained in that direction, otherwise the buckling load factor may apply to an unexpected out-of-plane buckling mode. A general restraint is usually the most convenient way to achieve this. For example, applying a general restraint of RRFRRR to a plane frame in the XY plane will prevent all out-of-plane translations. Conversely, it is also important that you don’t prevent node movements that can occur in the real structure. For example, consider a plane frame rafter that is restrained in the out-of-plane direction at the two ends via an RRFRRR general restraint, but which is able to buckle in the out-of-plane direction between the ends. If you subsequently add some intermediate nodes to the rafter, they will also get the general restraint and this will prevent them from translating out-of-plane, changing the out-of-plane buckling characteristics of the rafter. To avoid this, you could apply restraints of RRRRRR to the intermediate nodes so that they don’t get the general restraint. Note that a static analysis of a plane frame is not as sensitive to out-of-plane restraints as a buckling analysis because static analysis out-of-plane displacements generally only occur if out-of-plane loads are applied. This is not true of a buckling analysis which can cause buckling in any direction, even if there are no loads in that direction. Buckling analysis with secondary members Structures are often modelled with the secondary members such as ties or bracing removed. If these members are required to prevent buckling of the major members in the real structure then they should be included in the buckling analysis model, otherwise the buckling capacity of the structure will be underestimated by the analysis. This is particularly true of tower structures that contain large numbers of slender members that prevent buckling of the major support members. Buckling analysis with tension-only or compression-only members Extra care must be taken with buckling analysis of structures that contain tension-only or compression-only members. For example, consider a portal frame building modelled in 3D with tension-only wall bracing members that prevent the building from swaying longitudinally. Special treatment is required for the load cases that contain predominantly gravity loads which would cause all the wall braces to go into compression and therefore become disabled. In such load cases, the buckling analysis would yield very low buckling load factors because the wall bracing members would have been disabled and a longitudinal sway buckling mode at very low load would result. Of course, in the real structure this could not happen because the wall brace members would prevent it as soon as the sway mode was initiated. One solution is to introduce a very small horizontal load into these load cases which is small enough to have a negligible effect on the static analysis results but large enough to cause the wall brace members to go into tension. The result is that they are not removed from the buckling analysis model and are therefore able to prevent the unrealistic longitudinal sway buckling mode. 506

Analysis

Similar situations can occur in any structures that contain tension-only or compression-only members. Buckling analysis with cable members Extra care is needed for structures containing cable members because of their highly nonlinear nature. Because the axial force distribution in cable structures can change dramatically as the load factor is increased beyond the working load, it is recommended that the buckling analysis be performed on combination load cases that factor the working loads up close to the buckling load and result in buckling load factors that are close to 1.0. For example, if a buckling analysis of a working load case for a cable structure yields a primary buckling load factor of 5.2, you could create a combination load case which factors up the working loads for the particular load case by 5.0 say, and then re-do the buckling analysis for the combination load case instead. If the subsequent buckling load factor is 0.90 say, then the final load factor (for the working load case) is 5.0 x 0.90 = 4.50. Buckling analysis with plate elements Because the plates in SPACE GASS are linear elements with no adjustment of stiffness due to P-delta effects, they will not buckle regardless of the load applied. Buckling instabilities Occasionally, you may find that a requested buckling mode can't be calculated and "Unstable" appears in the buckling output report. This occurs when a node floats free due to local buckling of all of the members to which the node is connected. Sometimes it is possible to avoid this problem and calculate higher order buckling modes by adding intermediate nodes to the members which have buckled. Modelling multiple structures in one job It is sometimes useful to model more than one structure in a single job, however this is not recommended if you are performing a buckling analysis to obtain compression effective lengths. The buckling analysis finds the lowest buckling load factor for the entire model and then calculates the effective lengths for all the members in the model based on that buckling load factor. For example, if you have modelled structure A and structure B in one job, and structure A has the lowest buckling load factor, the effective lengths for structure B will be incorrectly based on the buckling load factor from structure A. SPACE GASS can't detect if there are multiple structures in a single model and therefore you need to put them into separate jobs if you want to use effective lengths from a buckling analysis. Buckling analysis of spectral load cases Spectral load cases are not included in a buckling analysis. Furthermore, if you perform a buckling analysis on a combination load case that contains spectral load cases, only the nonspectral load cases in that combination will be considered.

507


Running a buckling analysis You can run a buckling analysis by selecting "Buckling Analysis" from the Analysis menu. The input data requirements for a buckling analysis are the same as those for a static analysis. No extra buckling data is required. You do not have to run a static analysis before a buckling analysis.

Load case list If you want to analyse all load cases then this field can be left blank, otherwise you should type in a list of load cases (separated by commas or dashes) that you want analysed. For the fastest analysis time you should generally analyse only the load cases that can occur in reality. For example, there is no point in analysing a live load case on its own because it can't occur in real life without being combined with dead load. This means that you should generally analyse just the combination load cases and not the primary load cases that the combinations are made from. When specifying the load case list, you can either list them directly, or you can click the button to display and select from a list of the load cases currently in the job as shown below.

508

Analysis

Tolerance The accuracy to which the buckling load factors will be calculated. For example, a tolerance of 0.01 means that the load factors will be within +/- 0.01 of the exact value.

Each extra decimal place in the tolerance will increase the number of iterations per mode by 3 or 4. For example, a tolerance of 0.001 will require 3 or 4 more iterations per mode than a tolerance of 0.01. Load factor upper limit The upper limit above which the buckling analysis will no longer search for buckling load factors. Once this limit is reached, the analysis will stop, even if not all requested buckling modes have been calculated. Load factor lower limit The lower limit below which the buckling analysis will not search for buckling load factors. Buckling modes The number of buckling modes that are required. Normally only the first buckling mode is of interest, because beyond that the structure has usually collapsed and further modes are of academic use only. If the first buckling mode is caused by local buckling of a slender member or group of members rather than the frame as a whole, the model should be changed so that overall frame buckling occurs instead. One way of achieving this could be to change the slender members into tension-only members so that they become disabled rather than buckle (see also Members). You should view the buckling mode shapes graphically to determine whether or not overall frame buckling has occurred. Retain results of other load cases If you have specified that not all load cases are to be analysed and, if results already exist for some of the non-specified load cases, you can choose to retain them or have them deleted. 509


Check for non-existent load cases If you have defined combination load cases that contain other load cases which don’t yet exist, this option will detect and report them. It is optional because some users prefer to have a standard set of combination load cases that contain primary load cases which are just ignored during the analysis if they don’t exist. Stabilize unrestrained nodes Nodes that are free to rotate or translate in one or more directions without resistance from interconnecting members, restraints or constraints can be automatically restrained during the analysis so that instabilities don’t occur. For example, if a node was connected to a number of members, all of which were pin-ended, a rotational instability would normally result due to the unrestrained rotation of the node. However, the stabilize option would apply a temporary rotational restraint to the node during the analysis, preventing an instability. Although this solves many instabilities, it doesn’t fix them all, and the prevention of nontrivial instabilities is still dependent on good modelling practice. Extra iterations for mode shape accuracy The buckling analysis is complete when the buckling load factor has reached the desired accuracy (as specified by the tolerance), however it is possible that at this point the buckling mode shapes are not totally accurate. Mode shape accuracy can be achieved by turning on the "Extra iterations for mode shape accuracy" option, however because buckling mode shapes are only used as a visual aid to assess the buckling location and its shape then the extra iterations and analysis time involved is not usually warranted. Solver The "Paradise" solver is a new parallel multi-core sparse solver that fully utilizes the multiple cores in a modern computer's CPU. All of the available cores are run in parallel to get the maximum possible analysis speed. It also takes full advantage of the sparseness of the structural matrix during the solution to minimize memory requirements and further increase the speed. The Paradise solver is the recommended setting for all static analyses. One current restriction of the Paradise solver is that it doesn't generate buckling mode shapes and so if mode shapes are essential then you should use the Wavefront solver instead. This restriction is likely to be removed in a future version. Note that buckling mode shapes are for visual purposes only and do not affect the calculation of the buckling load factor, the member effective lengths or any of the other modules that use the buckling analysis results. The "Wavefront" solver also takes into account the sparseness of the matrix but doesn't run in multi-core mode. It is generally slower than the Paradise solver and can be used if the Paradise solver is unable to obtain a solution or if you require buckling mode shapes. The "Watcom" solver is the one used in pre-SPACE GASS 12 versions. It is considerably slower than the Paradise and Wavefront solvers and is therefore of limited use. All three solvers should yield virtually identical results. Optimization method The wavefront optimizer can be de-activated or it can be operated in one of four modes as follows.

510

Analysis 1. No optimization 2. Auto mode - SPACE GASS trials the "General" and various "Linear" modes and then uses the one that gives the smallest frontwidth. It doesn't add significant time to the analysis and is the recommended setting. 3. General mode - SPACE GASS determines the path along which optimization proceeds through the structure. 4. Linear mode - You select from the X, Y or Z axes or a vector along which optimization proceeds in a straight line through the structure. 5. Circular mode - You select either of the X, Y or Z axes about which optimization proceeds around an arc through the structure. See also The wavefront optimizer. Optimization axis If you have selected "Linear" or "Circular" for the wavefront optimization mode then you must select the axis or vector along or about which optimization will proceed. See also The wavefront optimizer. Coordinates of optimization centre If you have selected "Circular" for the wavefront optimization mode then you must select the centre of rotation about which optimization will proceed. See also The wavefront optimizer. Axial force distribution The buckling properties of a structure are largely dependent on the axial force in the members. The buckling analysis module performs its own static analysis first to determine the axial force distribution and you can nominate either linear or non-linear for this initial static analysis phase. Generally, the choice between linear or non-linear doesn't significantly affect the buckling load factor and, because linear is faster, it is recommended for most frames. Naturally, some structures, such as those containing cable members, which cannot be analysed linearly, require you to select non-linear.

When all of the information has been entered, the buckling analysis module calculates the buckling load factor and mode shapes for each load case and then saves them ready for graphical or text report output. If you want to terminate the analysis before it is finished, just press ESC or the right mouse button.

Because plates are linear elements, they will not buckle regardless of the load applied.

511


Buckling analysis results At the end of the buckling analysis, a message showing the lowest buckling load factor is displayed as follows.

This gives an instant indication of whether the buckling capacity of the frame has been exceeded or not. A buckling load factor of less than SF x 1.0, where SF is a suitable safety factor would be unsatisfactory. Based on the buckling load factor for each load case, a simple formula is then used to calculate the member effective lengths as described in "Buckling effective lengths". The effective lengths can then be automatically transferred into the steel member design modules. For a more detailed list of the buckling load factors and member effective lengths for each load case, you should view or print a report that includes the buckling load factors and/or buckling effective lengths. If you get buckling load factors that are below the minimum allowable value (eg. shown as "<0.001" when the minimum allowable value is 0.001), this could indicate an instability problem rather than a buckling problem. It is even more likely to be an instability problem if the low buckling load factors occur in every load case. By displaying the buckling mode shapes, you can generally see where the buckling would occur, however some models show no movement at all. In these cases, the buckling generally involves node rotations without any translations, making it difficult to see the source of the buckling. The buckling load factor report, however, gives the locations of the maximum node translations and rotations which can help to identify where the buckling is happening. Load Load Node at Node at Case Mode Factor Tolerance Iterations Max Trans Max Rotn 1 1 3.207 0.008 11 4 (X) 3 (Z) 2 1 0.801 0.008 8 4 (X) 3 (Z)

In the above example, the buckling mode involves translations in the X-axis direction and rotations about the Z-axis. If you want to display any higher order mode shapes, just press the "Filters" toolbar button and then list the mode shapes required in the "Buckling modes" field.

512

Analysis

If a frame appears to buckle in the wrong direction, it is because the buckling mode shape diagrams are only intended to show the mode of buckling and not its direction or magnitude. When displaying the buckling mode shapes graphically, SPACE GASS makes no attempt to show the member curvature between end nodes (ie. the node positions are simply joined by straight lines). You can, however improve the look of the mode shapes by adding intermediate nodes to the members.

513


Dynamic frequency analysis Dynamic frequency analysis The SPACE GASS dynamic frequency analysis module is able to analyse multiple mass load cases consisting of self mass and/or user defined lumped masses in a single run. For each mass load case it calculates the natural frequency (eigenvalue), period and mode shape (eigenvector) for any user defined number of vibration modes. The natural frequencies, periods and mode shapes comprise the dynamic properties of the structure. Important points 1. A dynamic frequency analysis is linear only and therefore cannot be performed if your model contains cable elements. 2. Because it is linear, a dynamic frequency analysis treats tension-only and compression-only members as normal members that can take tension and compression.

You must perform a dynamic frequency analysis before performing a dynamic spectral response analysis.

514

Analysis

Modelling considerations The dynamic properties of a structure are dependent only on its geometric properties, stiffness and mass. The geometric properties and stiffness of the structure are determined automatically from the node coordinates, member connectivity and fixity, plate connectivity, node restraints, section properties and material properties. The structure mass is made up of self mass (applied as lumped masses on every node) and extra applied lumped masses. Self mass can be calculated automatically during the dynamic frequency analysis if requested, while any extra lumped masses must be pre-defined by the user. In most cases, lumped masses placed at nodes are an adequate means of defining the mass distribution throughout the structure. However, where the distribution of mass is critical, extra nodes may be required. For example, consider a vertical cantilevered structure (such as a pole or tower). In order to accurately determine the natural frequencies you must define the distribution of mass up the cantilever by adding intermediate nodes with masses applied to them. A similar situation applies with a continuous beam where the mode shapes between supports are important. As a general rule, extra intermediate nodes (with masses applied) should be added to members for which the mass is a significant part of the total mass of the structure. Structures with a small number of members are often affected in this way. Dynamic mode shape deflections are calculated and output at nodes only. Therefore, in order to get realistic looking mode shapes it is sometimes necessary to add intermediate nodes to some members, particularly if the deflected shapes of these members have significant curvature. If the local deflected shape of a member is of interest then the distribution of mass along it will also be important and the requirement for intermediate nodes will apply anyway.

The dynamic frequency analysis module cannot analyse structures that contain cable members.

515


Running a dynamic frequency analysis You can run a dynamic frequency analysis by selecting "Dynamic Frequency Analysis" from the Analysis menu. The dynamic frequency analysis is a linear analysis and hence cannot be used with models that contain cable members. Furthermore, it treats tension-only and compression-only members as normal members that can take tension and compression. Note that the requirement to save the stiffness matrix during an initial static analysis is no longer required for a dynamic frequency analysis.

Load case list If you want to analyse all load cases then this field can be left blank, otherwise you should type in a list of load cases (separated by commas or dashes) that you want analysed. When specifying the load case list, you can either list them directly, or you can click the button to display and select from a list of the load cases currently in the job as shown below.

516

Analysis

Note that only the load cases that contain lumped masses or self-weight are considered during a dynamic frequency analysis. Load cases that contain self-weight with other static loads and no lumped masses are not considered, however load cases that contain only self-weight are considered. Any static loads that exist in the dynamic load cases are ignored. Consider the following examples: Contents of load case Masses only Self-weight only Static loads only Masses + self-weight Masses + static Masses + self-weight + static Self-weight + static

Considered Yes Yes No Yes Yes (static loads ignored) Yes (static loads ignored) No

Self mass The self mass of the structure can be calculated automatically by SPACE GASS and included in the dynamic frequency analysis. This can be done either by adding self-weight to a load case that contains lumped masses or by combining lumped mass and self-weight load cases into a combination load case. Self mass is applied by calculating the mass of each member and then applying half of it as translational lumped masses to each of the member end nodes in each of the unrestrained X, Y and Z global axis directions. The mass of each plate is also calculated and applied to its perimeter nodes Self mass generation does not calculate rotational masses because of the large number of extra masses that would be calculated for a fairly insignificant improvement in results accuracy. If required, rotational self mass must be manually applied as rotational lumped masses. See also Lumped masses. See also Self-weight.

517

SPACE GASS 12 User Manual Tolerance (Hz) The accuracy to which the dynamic natural frequencies will be calculated. For example, a tolerance of 0.001 means that the frequencies will be within +/- 0.001 of the exact value. The tolerance can also have a significant effect on the accuracy of the mode shapes. While the mode shapes are usually of secondary importance if only a dynamic frequency analysis is done, they are very important if the frequency analysis is followed by a dynamic response analysis. Inaccurate mode shapes from the frequency analysis can cause significant errors in the mass participation factors from the response analysis and its results in general. Even if a natural frequency is accurate to within 0.01Hz, its corresponding mode shape may not be accurate enough for a dynamic spectral response analysis. If the "Extra iterations for mode shape accuracy" option is turned on (see below) then SPACE GASS will detect significantly incorrect mode shapes during the frequency analysis and will correct them automatically by doing more iterations. Small mode shape inaccuracies cannot be detected by the frequency analysis, however they sometimes make themselves evident in the response analysis by mass participation factors that exceed 100%. A warning is given if this occurs and you should repeat the frequency analysis using a smaller tolerance. If the results of the frequency analysis won’t be used in a response analysis then a tolerance of 0.01 is more than enough, however if a response analysis is to follow then a tolerance of 0.001 or less should be used.

Each extra decimal place in the tolerance will increase the number of iterations per mode by 3 or 4. For example, a tolerance of 0.0001 will require 3 or 4 more iterations per mode than a tolerance of 0.001. Frequency upper limit (Hz) The upper limit above which the dynamic frequency analysis will no longer search for natural frequencies. Once this limit is reached, the analysis will stop, even if not all requested dynamic modes have been calculated. Frequency lower limit (Hz) The lower limit below which the dynamic frequency analysis will not search for natural frequencies. Dynamic modes The dynamic frequency analysis module calculates the mode shapes, natural frequencies and natural periods for the number of dynamic modes requested. It also sorts them into ascending frequency order. See also View diagrams. Frequency shift (Hz) The dynamic frequency analysis normally calculates natural frequencies starting from 0Hz and working upwards, however if a frequency shift is specified then the frequencies below the frequency shift value are skipped. For example, if your structure has natural frequencies of 1.2Hz, 3.2Hz, 6.7Hz, 10.2Hz, 15.3Hz and 16.1Hz but you are only interested in the frequencies above 10Hz, you could specify a frequency shift of 10Hz. This would skip the lower three modes (saving you considerable analysis time) and just calculate frequencies 10.2Hz, 15.3Hz and 16.1Hz.

518

Analysis Retain results of other load cases If you have specified that not all load cases are to be analysed and, if results already exist for some of the non-specified load cases, you can choose to retain them or have them deleted. Check for non-existent load cases If you have defined combination load cases that contain other load cases that don’t yet exist, this option will detect and report them. It is optional because some users prefer to have a standard set of combination load cases that contain primary load cases which are just ignored during the analysis if they don’t exist. Stabilize unrestrained nodes Nodes that are free to rotate or translate in one or more directions without resistance from interconnecting members, plates, restraints or constraints can be automatically restrained during the analysis so that instabilities don’t occur. For example, if a node was connected to a number of members, all of which were pin-ended, a rotational instability would normally result due to the unrestrained rotation of the node. However, the stabilize option would apply a temporary rotational restraint to the node during the analysis, preventing an instability. Although this solves many instabilities, it doesn’t fix them all, and the prevention of nontrivial instabilities is still dependent on good modelling practice. Extra iterations for mode shape accuracy The dynamic frequency analysis is complete when the natural frequencies have reached the desired accuracy (as specified by the tolerance), however it is possible that at this point the dynamic mode shapes are not totally accurate. Mode shape accuracy can be achieved by turning on the "Extra iterations for mode shape accuracy" option, however if the dynamic mode shapes are only used as a visual aid to assess the vibration location and its shape then the extra iterations and analysis time involved may not be warranted. If, however, a dynamic response analysis is to be done based on the frequency analysis then the mode shapes are very important and it is imperative that the "Extra iterations for mode shape accuracy" option is turned on. Even with the extra iterations, in some cases the mode shapes may still not be accurate enough (as sometimes evidenced by a mass participation factor from the response analysis that exceeds 100%) and further accuracy can then only be achieved by using a smaller tolerance. Solver The "Paradise" solver is a new parallel multi-core sparse solver that fully utilizes the multiple cores in a modern computer's CPU. All of the available cores are run in parallel to get the maximum possible analysis speed. It also takes full advantage of the sparseness of the structural matrix during the solution to minimize memory requirements and further increase the speed. The Paradise solver is the recommended setting for all dynamic frequency analyses. The "Wavefront" solver also takes into account the sparseness of the matrix but doesn't run in multi-core mode. It is generally slower than the Paradise solver and can be used if the Paradise solver is unable to obtain a solution. The "Watcom" solver is the one used in pre-SPACE GASS 12 versions. It is considerably slower than the Paradise and Wavefront solvers and is therefore of limited use. All three solvers should yield virtually identical results.

519

SPACE GASS 12 User Manual Optimization method The wavefront optimizer can be de-activated or it can be operated in one of four modes as follows. 1. No optimization 2. Auto mode - SPACE GASS trials the "General" and various "Linear" modes and then uses the one that gives the smallest frontwidth. It doesn't add significant time to the analysis and is the recommended setting. 3. General mode - SPACE GASS determines the path along which optimization proceeds through the structure. 4. Linear mode - You select from the X, Y or Z axes or a vector along which optimization proceeds in a straight line through the structure. 5. Circular mode - You select either of the X, Y or Z axes about which optimization proceeds around an arc through the structure. See also The wavefront optimizer. Optimization axis If you have selected "Linear" or "Circular" for the wavefront optimization mode then you must select the axis or vector along or about which optimization will proceed. See also The wavefront optimizer. Coordinates of optimization centre If you have selected "Circular" for the wavefront optimization mode then you must select the centre of rotation about which optimization will proceed. See also The wavefront optimizer.

When all of the information has been entered, the dynamic frequency analysis module calculates the natural frequencies, periods and mode shapes for each load case and then saves them ready for graphical or text report output. If you want to terminate the analysis before it is finished, just press ESC or the right mouse button.

520

Analysis

Dynamic frequency analysis results The natural frequencies, periods and mode shapes calculated during the static analysis can be included in a report. They can also be viewed graphically in animated diagrams superimposed over the undeformed frame as described in "View dynamic mode shapes". Mode shape displacements are relative only. They define the mode shape, not its magnitude. You can’t compare the displacements of different mode shapes in an attempt to determine which mode will result in the largest displacements. The scale factor for the displacements of each mode shape is unique to that mode. The mode shapes in SPACE GASS are normalized. This means that the translations and rotations in a mode shape will have been adjusted such that each translation or rotation is divided by the absolute value of the largest translational displacement for the mode shape under consideration. This makes it easier for you to relate the displacement of a particular node to the maximum displacement within a mode shape. For example, a normalized displacement of 0.60 indicates that the node moves by an amount which is 60% of the maximum displacement in that particular mode shape. If you wish to use the dynamic frequency analysis results to perform an earthquake analysis, refer to "Dynamic spectral response analysis".

521


Dynamic spectral response analysis Dynamic spectral response analysis The SPACE GASS spectral module performs a dynamic spectral response analysis of structures subjected to earthquake loads given in the form of acceleration response spectra. Its general approach means that the spectral module is not just restricted to earthquakes, but can calculate the maximum response of a structure subjected to any ground vibration provided that all supports are vibrating in phase (ie. the same response spectrum is applied at all supports simultaneously). The spectral module considers the vibration of the structure and identifies the maximum values that result from the vibration. Generally, the maximums at different points of the structure occur at different times during the dynamic event. Consequently, the spectral results do not represent an equilibrium state of the structure, rather an envelope of the maximums. Furthermore, because the earthquake action has no sign (ie. its accelerations are both positive and negative), the maximum values have no sign and hence the sign of the results is indeterminate. Usually, the results are dominated by one of the mode shapes which SPACE GASS can identify and apply its sign to the results. Alternatively, you can select which mode shape the sign should be taken from. The spectral module is not code specific, however for ease of use with the Australian, New Zealand and Indian loading codes, many of the analysis input parameters have alternative code specific input options. These options require you to simply select from tables taken from the code rather than having to type in numeric values. Future versions will include these input aids for other international codes also. The earthquake loads are provided in the form of curves called "acceleration response spectra" which graph acceleration versus period. Each spectral curve is derived from the timehistory record of a ground vibration for a specific level of damping, and is not dependent in any way on the properties of the structure being analysed. Usually, for one earthquake, there are several spectral curves for different damping ratios (eg. 0%, 1%, 2%, 5% and 10% of the critical damping). In the design codes, the spectral curves are derived from a set of earthquake records which are smoothed and averaged. A spectral curve library containing some standard (unauthorised) curves is supplied with SPACE GASS. The built-in graphical spectral curve editor allows you to modify or create your own spectral curves as required. The acceleration values in a spectral curve are always specified in terms of g (acceleration due to gravity) units. Before being used in an analysis, SPACE GASS automatically multiplies them by the dimensionless spectral curve multiplier and by the appropriate value of g to yield acceleration units that are consistent with the currently selected units system. For an accurate spectral analysis, it is important that the spectral load cases have been defined correctly and that appropriate combinations of the spectral load cases have been specified. For more information, refer to "Spectral load data". The results of the spectral analysis include deflections, forces, moments and reactions that can be displayed graphically, printed, or used in a steel design in the same way as the results from a static analysis. It is also possible to combine spectral load cases with static load cases in combination load cases. Important points

522

Analysis 1. A dynamic spectral response analysis is linear only and therefore cannot be performed if your model contains cable elements. 2. Because it is linear, a spectral analysis treats tension-only and compression-only members as normal members that can take tension and compression. 3. P-andP- effects are not taken into account during a spectral analysis. 4. The spectral analysis must be repeated after a static or dynamic frequency analysis because its results will have been deleted.

Refer to "Dynamic response analysis results" for details and interpretation of the results of a dynamic spectral response analysis.

523


Running a dynamic spectral response analysis You can run a dynamic spectral response analysis by selecting "Dynamic Response Analysis" from the Analysis menu.

Before a dynamic spectral response analysis can proceed, you must have performed a dynamic frequency analysis.

Load case list Leave blank if you want to analyse all spectral load cases, otherwise enter the load cases (separate by commas/dashes) you want analysed. When specifying the load case list, you can either list them directly, or you can click the button to display and select from a list of the load cases currently in the job as shown below.

524

Analysis

Retain results of other load cases Check this box if you want to keep the analysis results of previously analysed spectral load cases. Otherwise, if they are not being re-analysed in the current session, they will be discarded. Loading code This allows you to select the loading code to be used. If you choose the AS, NZS or IS code, you should ensure that you have also selected spectral curves for that same code in your spectral load data. One major difference between the "General" loading code and the other codes is that the spectral curve multiplier must be manually defined for General, whereas it can be calculated based on code specific factors for the AS, NZS and IS codes. Limit state - NZS1170.5 only For NZS, you must choose between serviceability or ultimate limit states together with an appropriate ductility factor.

The selected ductility factor is only used if a non-NZS spectral curve is used in the spectral load data. If you have used a predefined NZS spectral curve then the ductility factor is derived from it. Auto scaling of base shear This is a code related parameter that instructs the program to scale the results so that the sum of the support reactions obtained from the spectral analysis is not less than a user defined proportion of the total static force (or a user defined percentage of the structure’s weight for the "General" code). The static force for each mode is calculated based on the mass in the structure multiplied by the acceleration obtained from the spectral curve being used. It is calculated for each axis direction and for the earthquake direction as defined by the direction vector in the spectral load data. The static force used for base shear scaling is taken from the static force in the earthquake direction for the dominant mode (ie. the mode with the largest mass participation factor). If the base shear is less than the user defined percentage of the static force (NZS) or 525

SPACE GASS 12 User Manual 100% of the static force (IS) then the results (deflections, forces, moments and reactions) are scaled up accordingly. No scaling is done for the AS code. For the "General" code, the results are scaled up if the base shear is less than the user defined percentage of the mass in the structure. This is equivalent to scaling based on a static force calculated using an acceleration of 1g. Site subsoil class - NZS1170.5 only The site subsoil class is only used when non-NZS spectral curves are used. A setting of "Auto" forces the site subsoil class to be taken from the spectral curve and is not suitable for non-NZS spectral curves. For NZS spectral curves the site subsoil class is always taken from the curve. Horizontal base shear factor (%) - General only A "General" loading code specific factor that controls the scaling of the results so that the sum of the support reactions resolved along the axis of the direction vector equals the weight of the structure (including applied lumped masses) multiplied by the horizontal base shear factor. It is used if the direction vector is predominantly horizontal. For example, if you select a horizontal base shear of 3% the total reaction vector must be equal to 3% of the weight of the structure. Vertical base shear factor (%) - General only A "General" loading code specific factor that controls the scaling of the results so that the sum of the support reactions resolved along the axis of the direction vector equals the weight of the structure (including applied lumped masses) multiplied by the vertical base shear factor. It is used if the direction vector is predominantly vertical. For example, if you select a vertical base shear of 2% the total reaction vector must be equal to 2% of the weight of the structure. Base shear factor (%) - NZS1170.5 only Controls the scaling of the results so that the sum of the support reactions resolved along the axis of the direction vector is not less than the total static force (resolved in the same direction) multiplied by the scaling factor. For example, if you select a scaling factor of 80% the total reaction vector will be not less than 80% of the total static force vector. Factors There are a number of code specific factors that can be typed in directly or calculated automatically based on descriptions of the structure location, structure importance and construction method. They are used to calculate the spectral curve multiplier and other parameters in the spectral analysis. Sign of the results Because the results of a response spectrum analysis are a combination of a number of mode shapes, the final sign of the results has to be determined. Choosing "No sign" is of limited use and means that all deflections, forces, moments and reactions will be positive. Choosing "Auto Sign" means that the sign of the predominant mode shape will be applied to the results. Choosing "Select Mode" tells the program to extract the sign from a nominated mode shape. Spectral curve multiplier The spectral curve multiplier is used to control the scale of the spectral curve acceleration values. It can be typed in directly or, by clicking the button next to the spectral curve multiplier field, can be defined via various code specific factors. For AS1170.4 it is based on probability, hazard, structural ductility and performance factors, for NZS1170.5 it is based on hazard, return period, near-fault and structural performance factors, and for IS1893 it is based on the zone factor, damping multiplying factor, importance factor and response reduction

526

Analysis factor. Each of the code specific factors can be typed in directly or calculated automatically based on descriptions of the structure location, structure importance and construction method. Mode combination method The results for spectral load cases that contain more than one mode shape are obtained by combining the results for each of the mode shapes. You can choose between: 

SRSS - Square Root of the Sum of Squares The simplest and most commonly used mode combination method that works well for most situations.



CQC - Complete Quadratic Combination Recommended when some of the mode shapes to be combined have natural frequencies that are close together.

Either method can be used regardless of the spectral curve damping factors. When all of the information has been entered, the dynamic spectral response analysis module performs its calculations for each load case and then saves them ready for graphical or text report output. If you want to terminate the analysis before it is finished, just press ESC or the right mouse button.

527


Dynamic spectral response procedure For each spectral load case, the analysis module calculates: 1. 2. 3. 4. 5. 6. 7. 8.

Total static (earthquake) force in each global axis direction. Dominant period in each global axis direction. Mass participation factor for the dominant mode in each global axis direction. Total mass participation factor in each global axis direction. Total mass participation factor. The mode to be used for determining the sign of the results. Node displacements for each mode. Mass participation factor in the earthquake direction for each mode.

The following calculations are then performed: 1.

Forces, moments and reactions are calculated from the node displacements for each mode.

2.

Displacements, forces, moments and reactions for each mode are combined into a single set of values for all the modes combined. This is done using SRSS or CQC as specified by the user.

3.

If base shear scaling is requested, the displacements, forces, moments and reactions are then scaled by a factor so that the base shear is equal to the base shear factor times the total mass (for "General") or not less than the base shear factor times the total static force for the dominant mode (for NZS or IS loading codes). Note that the base shear is simply the X, Y and Z reactions resolved into a vector in the direction of the earthquake. Similarly, the total static force is the X, Y and Z static forces resolved into a vector in the direction of the earthquake. For "General", if the direction vector is predominantly horizontal then the horizontal base shear factor is used (this is the normal case), otherwise the vertical base shear factor is used.

For a detailed explanation of the dynamic spectral response analysis results, refer to "Dynamic response analysis results".

528

Analysis

Dynamic spectral response analysis results The results of a spectral response analysis include normal deflections, forces, moments and reactions that can be displayed graphically, printed or used in a steel design in the same way that the results of a static analysis are used. In addition, spectral load cases and static load cases can be mixed together in combination load cases. The output results also include a summary of the analysis input parameters and details of the governing mode shapes, total static forces, total masses and mass participation factors. Details are given for the three global axis directions and for the direction vector. The key output results are explained in more detail as follows: Total static force The earthquake force calculated by an equivalent static method for each global axis direction. Total mass The total mass (including self mass if self weight is included in the mass load cases) applied to the model for each global axis direction. Note that any mass applied to restrained degrees of freedom is ignored. Mass participation factor The results are highly sensitive to the number of mode shapes included in the analysis. An insufficient number of modes will result in an inaccurate solution. The mass participation factor (MPF) represents the contribution of a particular mode shape to the overall dynamic response of the structure. Each mode has its own MPF. The total MPF for each direction is a reliable indicator of the number of modes required. If all modes are considered then the sum of the MPF’s (the total MPF) will be 100%. In reality, we only consider a finite number of modes and the total MPF should be at least 90% for a good result. If the total MPF is less than 90% then more modes should be included in the analysis. Usually, an earthquake is applied along one of the two horizontal axes, as defined by the direction vector. For example, an earthquake acting in the X direction would have a direction vector of Dx = 1.0, Dy = 0.0 and Dz = 0.0. In this case, the total MPF in the X direction should be greater than 90%. The values of the total MPFs in the other two directions are not important. A MPF that exceeds 100% indicates that the mode shapes from the dynamic frequency analysis are not accurate enough. If this happens, you should repeat the dynamic frequency analysis using a smaller tolerance. Base shear The horizontal reaction in each global axis direction shown as a percentage of the total mass. This should match the reactions shown graphically. The table in the output report showing the mass participation factors for each mode shape individually gives a good indication of the contribution of each mode shape in the overall dynamic response of the structure. From it you can quickly see which mode is dominant. DYNAMIC RESPONSE SPECTRUM (kN,T,Sec,Hz) ------------------------Spectral case 5: Sample AS1170.4 Case Mass load case: 3

529

SPACE GASS 12 User Manual Direction vector: Dx = 1.000, Dy = 1.000, Dz = 1.000 Auto scaling of base shear: AS1170.4 Vertical direction: Y-Axis Base shear: Not less than 80% of total static force Results scaled by factor: 2.825 Site factor: 0.670 Sign of the results: Mode shape 1 (Calculated) Acceleration coefficient: 0.080 Importance factor: 1.000 Structural response factor: 4.500 Spectral curve multiplier: 0.017778 Mode combination method: SRSS (Square Root of the Sum of Squares) Total MPF for Total Dominant Static Total Dominant Mass Part Base Direction Mode Force Mass Mode Factor Shear X-Axis 1 0.5371 2.1209 99.999% 100.000% 1.056% Y-Axis 3 0.2686 1.1209 29.745% 29.745% 0.023% Z-Axis 0 0.0000 0.0000 0.000% 0.000% 0.000% Mode Damping Natural Natural Mass Part Direction Shape Spectral Curve Factor Period Frequency Factor Vector 1 NEWCASTLE 2% 2.0% 0.4378 2.284 65.419% Vector 3 NEWCASTLE 0% 0.1% 0.0133 75.470 10.365% Total 75.783%

Spectral case 6: Sample General Case Mass load case: 2 Direction vector: Dx = 1.000, Dy = 1.000, Dz = 0.000 Auto scaling of base shear: AS1170.4 Vertical direction: Y-Axis Base shear: Not less than 80% of total static force Results scaled by factor: 1.532 Site factor: 0.670 Sign of the results: Mode shape 1 (Calculated) Acceleration coefficient: 0.080 Importance factor: 1.000 Structural response factor: 4.500 Spectral curve multiplier: 0.017778 Mode combination method: SRSS (Square Root of the Sum of Squares) Total MPF for Total Dominant Static Total Dominant Mass Part Base Direction Mode Force Mass Mode Factor Shear X-Axis 1 0.8363 4.1209 99.999% 100.000% 2.244% Y-Axis 3 0.4182 4.1209 50.829% 91.077% 0.239% Z-Axis 0 0.0000 0.0000 0.000% 0.000% 0.000% Mode Damping Natural Natural Mass Part Direction Shape Spectral Curve Factor Period Frequency Factor Vector 1 AS1170.4 Vector 2 AS1170.4 Vector 3 AS1170.4 Vector 4 AS1170.4 Total 95.514%

530

S=.67 S=.67 S=.67 S=.67

5.0% 5.0% 5.0% 5.0%

0.6102 0.0253 0.0206 0.0153

1.639 50.096% 39.566 2.584% 48.544 25.278% 65.291 17.556%

Analysis

Analysis warnings and errors SPACE GASS performs numerous checks for illegal and inconsistent data. Many of these checks are done in the data input modules and any errors detected there must be corrected immediately. However, some errors and warnings such as instabilities and ill-conditioning cannot be detected until the analysis phase. If any errors in the data are detected, SPACE GASS lists them on the screen, aborts the analysis and then returns to the main menu, ready for correction of the offending items. Warnings are displayed at the end of the analysis and do not cause it to abort. Node # not found for member # A member is connected to a non-existent node. Direction node # not found for member # A member has referenced a non-existent direction node. Section # not found for member # A member has referenced a non-existent section property. Section # has impractically large section properties for the frame size The properties of a section are too large for the frame dimensions. This error is often due to the section properties being input in the wrong units. Material # not found for member # A member has referenced a non-existent material property. Member # has zero length A member is connected to two nodes with identical coordinates. Restraint applied to non-existent node # A restraint has been applied to a node which doesn’t exist. Slave node # not found A non-existent node has been specified as a slave node. Master node # not found for slave node # A non-existent node has been specified as a master node. A constraint has been applied to a restrained DOF on node # Any restrained degrees of freedom for a slave node cannot be constrained to a master node. Node # has been specified as both slave and master A master node cannot be the slave of another master node. Member # with PA<>0.0 must have identical Y and Z axis fixities at an end Because of the difficulty involved in calculating the stiffness matrix for a member with a nonzero principal angle when the member end fixities are about its non-principal axes, the Y and Z fixities at an end must be the same. Cable member # must not have any translational fixities released For stability, cable members must have all of their translational fixities fixed. Cable member # must not have member offsets 531

SPACE GASS 12 User Manual Cable members cannot have member offsets. Cable member # must not have semi-rigid joints Cable members are always assumed to be pin-ended, and hence cannot have semi-rigid joints. Member # must not have shear fixity released with semi-rigid joints Members with semi-rigid joints cannot have shear fixities released. This restriction only applies when the semi-rigid joint and the shear fixity act in the same plane. Node load on non-existent or dummy node #, load case # A node load has been applied to a non-existent node. Prescribed displacement on non-existent or dummy node #, load case # A prescribed displacement has been applied to a non-existent node. Concentrated load on non-existent member #, load case # A concentrated member load has been applied to a non-existent member. Distributed force on non-existent member #, load case # A distributed member force has been applied to a non-existent member. Distributed torsion on non-existent member #, load case # A distributed member torsion has been applied to a non-existent member. Prestress load on non-existent member #, load case # A prestress load has been applied to a non-existent member. Prescribed displacement applied to end of cable member #, load case # Nodes at the ends of cable members must not have prescribed displacements applied to them. Prescribed displacement applied to released restraint on node #, load case # Prescribed displacements can only be applied to node degrees of freedom which are restrained. Prescribed displ. applied to master constraint DOF on node #, load case # Prescribed displacements must not be applied to master node degrees of freedom which are constraining a slave node. Concentrated load is off the end of member #, load case # A concentrated member load has been located beyond the ends of the member. Concentrated load applied to cable member #, load case # Concentrated member loads must not be applied to cable members. Distributed force is off the end of member #, load case # A distributed member force has been located beyond the ends of the member. UDL must act over full length of cable member #, load case # Uniformly distributed loads applied to cable members must act over the entire cable length. Trapezoidal load applied to cable member #, load case # Distributed trapezoidal loads must not be applied to cable members. Distributed torsion is off the end of member #, load case # A distributed member torsion has been located beyond the ends of the member. 532

Analysis

Distributed torsion applied to cable member #, load case # Distributed torsion loads must not be applied to cable members. Load case # has been specified as both primary and combination Load cases can be primary or combination, but not both. Combination # contains non-primary load case # Combination load cases can only be made up from primary load cases. Combination load cases cannot be further combined. None of the load cases selected exist There are no valid load cases in the load cases list selected for analysis. Insufficient space on drive C, # bytes extra required The analysis module has detected that there is not enough space left on the hard disk for the analysis to run to completion. Extra space equal to the number of bytes shown is required. You should terminate the analysis, remove any unwanted data files or programs and then try the analysis again. Cable member # is ill-conditioned in load case # The program was unable to accurately calculate the cable geometry and stiffness matrix. Member # has buckled in load case #, axial load = 123.23. Continue? During a non-linear analysis, the program was unable to calculate the stiffness matrix for the member because its Euler buckling load was exceeded. If you continue, the member is simply disabled for the rest of the analysis iterations. Note that this message is the result of a simple local member buckling check only. Overall frame buckling or buckling of multiple members is not considered! The local member buckling messages can be suppressed by clearing the appropriate check box at the start of the analysis. Instability found at member # in load case # An instability has been detected at a specified member. The instability could be located at either end of the member. Not all load steps were completed The load was applied in more than one step, however it was stopped before all steps were completed. Because the full load was not reached, the results cannot be used for the load cases being analysed. WARNING: Possible ill-conditioning detected, check reactions Ill-conditioning may have been detected. If the reactions equal the applied loads then no illconditioning has occurred. This message is only a warning which can be suppressed from the output reports if necessary. WARNING: Analysis did not reach desired convergence in all load cases The level of convergence in a non-linear analysis has not reached the required convergence accuracy for some load cases. This is not necessarily fatal if the convergence achieved is close to that requested. Note also that some of the load cases may have fully converged and this can be checked by looking at the output reports.

533

Steel Member Design Steel member design Throughout this chapter it can be assumed that all information applies equally to all of the supported steel member design codes unless specifically stated otherwise. This chapter describes in detail the data required to be input before a design or check can proceed. It discusses the internal methods, philosophies and assumptions that the program uses as it designs or checks members, and it explains how to initiate the actual design or checking process once the steel member design data has been input. ! IMPORTANT NOTE ! Before you use the steel member design module, you should read all of the assumptions described later in this chapter (see also "Steel member design/check assumptions") to verify that its performance and capabilities are adequate for your situation. It is up to you to determine whether or not the steel member design module is suitable for your requirements. ! IMPORTANT NOTE ! Adjustments are required when designing or checking US HSS sections due to the practice of some steel manufacturers producing HSS sections with a wall thickness at the very low end of what the specifications allow. To account for this, the US section libraries supplied with SPACE GASS 12.27 and later include adjustments to the HSS section properties (depending on the type of HSS section) and no extra adjustments are made to their properties during an AISC 360-10 design or check. In SPACE GASS 12.26 and earlier, the US section libraries contained non-adjusted properties for HSS sections and so to allow for this their wall thickness was multiplied by 0.93 during an AISC 360-10 design or check. It is therefore important that you match the version of the US library with the same version of SPACE GASS, otherwise unsafe designs of HSS sections could result. It is also important that you don't use HSS sections from SPACE GASS 12.26 and earlier with other non-US design codes. The steel member design module is a general purpose design and code checking program which reads the frame analysis output data, calculates the critical location and load case for each member and then selects the most suitable steel member size from a library of standard sections. Alternatively, you may specify a steel member size to be checked and the program determines whether or not the member is adequate. For a given frame, you can specify any selected number of members to be designed or checked. The design module is also capable of passing the designed steel sizes back into the frame analysis data and re-analysing the structure. This process can be iterated until the results converge. It usually only takes two or three iterations. During the design/check phase SPACE GASS automatically calculates the load factor for limit states codes or combined stress ratio for working stress codes at numerous stations along each member. It considers yielding of the cross section, lateral buckling, slenderness ratios, and all possible combinations of shear, tension, compression and bending for both in-plane and out-of-plane failure.

535


The steel member design module doesn’t consider torsional effects. After all specified members have been designed or checked, a detailed report can be produced for each member showing the critical location or segment on the member, the critical load case, section properties, effective lengths, and the complete computations involved in the design. Sections of the report can be suppressed if required. A color-coded graphical representation of the design/check results can also be displayed. The SPACE GASS steel member design module can handle most types of steel members including beams, columns, ties, struts, braces, and members subjected to combinations of axial loads, shear forces and bending moments (uniaxial or biaxial). All references to BS5950 in this document apply to BS5950-1:2000. Although SPACE GASS still has a design module for BS5950:1990, it is now obsolete and is not referred to in this document. The AISC-LRFD, EUROCODE 3, AS4100, NZS3404, BS5950 and HK CP2011 modules assume that second order effects have been taken into account by a second order elastic analysis. Moment magnification is not considered. Refer to "Steel member input methods" for details on how to input steel member design data. Refer to "Running a steel member design" for details on how to perform a steel member design. Refer to "Steel member design results" for details and interpretation of the results of a steel member design.

536

Steel Member Design

Steel member input methods Before you can perform a steel member design, you must define each of the steel members you wish to design and then input some design parameters for each of them. This can be done in three ways as follows. 1.

Auto-create steel members This option performs a quick initial input of the steel members and their design parameters for the entire model or for any part of it that you wish to select. After the quick initial input, you can refine the design parameters for each steel member by using a steel member input form or datasheet (see items 2 and 3 below). You can also skip the auto-create step completely if you prefer to input the steel design data from scratch using a steel member input form or datasheet.

2.

Steel member input form This option allows you select a steel member graphically and then define or edit its design parameters via a form. It is restricted to one steel member at a time.

3.

Steel member input datasheet This option lets you select one or more steel members graphically and then define or edit their design parameters via a datasheet. It can handle multiple steel members, however they must have been previously defined using methods 1 or 2 above. Alternatively, you can select "Steel Member Design Input-Datasheet" from the Design menu to open a datasheet and input or edit design parameters for steel members regardless if they have previously been defined or not.

The recommended procedure is to use the auto-create tool to perform a quick initial setup of the steel members and then refine them using a steel member input form or datasheet. Each of the three input methods are explained in detail in the following sections. If you want to have multiple steel members with identical design parameters, you can copy the design parameters from one steel member to many others by using the "Copy steel member properties" tool. Note, however, that you can’t copy to steel members that haven’t been defined yet.

537


Auto-create steel members This tool automatically creates multiple steel design members (also known as "design groups") from a selection of analysis members. Each generated steel design member can contain multiple analysis members connected end-to-end, provided they are of the same cross section, are generally collinear and don’t extend past a major axis support. You can access the auto-create steel members tool by selecting "Steel Member Design InputAuto create multiple steel members" from the Design menu or selecting "Auto-create multiple steel members" from the floating menu. You can select analysis members from different locations throughout the model and with different section properties, and SPACE GASS will automatically sort through them and group them appropriately into steel design members. You can even select the entire model and have all of the steel design members created automatically. However, you should check the generated members to ensure that their effective lengths, restraints and other data are correct. The numbering convention adopted by this operation is such that the number of each generated steel design member is set to match the number of the first analysis member that it contains. This makes it easy to keep track of how the steel design members relate to the analysis members. However, please be aware that any existing steel design members that don’t follow this convention will be overwritten if their numbers clash with the new steel design members being generated. Of course, any steel design members that contain the selected analysis members will also be overwritten during the generation. After you have selected the analysis members to be grouped into steel design members, click the right mouse button and select "Auto-create multiple steel members" from the floating menu (or select "Ok" if you initiated the operation from the menu). You can then specify restraint, effective length and other data for the generated steel members via the forms shown below.

538

Steel Member Design

Specify Flange Restraints Manually Select this option if you want to directly specify all of the flange restraints along the generated steel members in the next form. Otherwise, the flange restraints will be placed in accordance with the data you specify in this form. End Flange Restraints These are the flange restraints that will be placed at the ends of the generated steel members. Intermediate Flange Restraints Flange restraints will be placed at the intermediate nodes along the generated steel members depending on which options you select in this area of the form. Your choices are any or all of the following: 1.

Apply flange restraints to all intermediate nodes

539

SPACE GASS 12 User Manual If selected, intermediate flange restraints of the type you specify will be placed on both flanges at every intermediate node.

2.

Apply flange restraints to nodes connected to other members If selected, intermediate flange restraints of the type you specify will be placed at the intermediate nodes that are connected to other members. You have the option of ignoring interconnecting members that lie in the plane of the steel member (ie. in the plane of the steel member’s web). You can also control which flanges to which the restraints are applied.

3.

Apply flange restraints to restrained intermediate nodes If selected, intermediate flange restraints of the type you specify will be placed at the intermediate nodes that have analysis restraints applied to them. Analysis restraints that only apply in the direction of the plane of the steel member’s web are ignored. Note that this only applies to normal analysis restraints and not the general restraint.

Tolerances The tolerances affect whether or not a selection of analysis members are suitable for grouping into a steel design member. A selection of analysis members of the same cross section connected end-to-end will be able to be grouped into a steel design member provided the bend angle, twist angle or step distance between adjacent analysis members do not exceed the tolerances you specify. Delete all Existing Design Groups First If you select this option, all steel design members will be deleted before the new steel members are generated. Otherwise, only those steel design members that contain the selected analysis members will be deleted before the generation. After clicking the "Next" button, the following form appears. For detailed information about the data in the form, refer to "Steel member design data".

540

Steel Member Design

All steel design members generated will be created with the data that you specify in this form. After the steel design members have been created, you should check each one, paying particular attention to the following: 1.

You should split any steel design member that extends past an interconnecting member that effectively acts as a major axis support point for the design member.

2.

If you have specified that bending effective lengths are to be calculated automatically based on the flange restraints, they will be calculated such that they never substantially exceed the actual length of the steel design member. If the unrestrained flange length is longer than this (ie. the bending effective length is longer than the steel design member length) then you should specify them manually rather than having them calculated automatically.

You can show the steel design members graphically by clicking the button near the bottom of the side toolbar. They show up as thickened lines that are drawn slightly shorter than their actual length so that you can easily see where they start and finish.

541


Steel design members can be viewed or edited graphically on an individual basis as described in "Steel member input form", "Steel member input datasheet" or via the steel member design datasheet. For an overview of the various methods available for inputting steel member design data, refer to "Steel member input methods".

542

Steel Member Design

Steel member input form This tool allows you to graphically define and edit steel design members (also known as "design groups"). Note that multiple steel design members can be defined in a single operation using the "Auto-create steel members" tool. You can access the steel member input form by selecting "Steel Member Design InputGraphical" from the Design menu or selecting some members and then "Steel Member Design Input (Form)" from the floating menu. It is recommended that you initially generate all the steel design members using the "Autocreate steel members" tool and then check and edit them on an individual basis using the procedure described here. Each steel design member contains one or more analysis members connected end-to-end. After you have selected the analysis members that you wish to include in a steel design member, click the right mouse button and select "Steel Member Design Input (Form)" from the floating menu (or select "Ok" if you initiated the operation from the menu). Because the top flange for a steel design group is taken to be the same as the top flange for the first member in the design group, it is important to be able to control which member comes first in the design group. Flange restraint positions are also referenced from the end of the first member in the design group. If you are inputting a new design group, the member that you select first will be placed first in the design group (assuming that it is at either end of the group). If you want to select a "first" member, you should pick it directly or ensure that it is the only member selected if you use a window. If you use a window and select a group of members initially, then the end one with the lowest member number will be placed first in the design group. In the steel member form that appears, type in the data for the selected design group, and then click the form Ok button. For detailed information about the data in the form, refer to "Steel member design data".

543


"Use Previous" button Click the "Use Previous" button to set all the data in the form to the same as when the form was previously used. You can show the steel design members graphically by clicking the button near the bottom of the side toolbar. They show up as thickened lines that are drawn slightly shorter than their actual length so that you can easily see where they start and finish. You can also show the flange restraints graphically by clicking the button near the bottom of the side toolbar. It enables you to see exactly where the flange restraints are and whether they are on the correct flange or not. For an overview of the various methods available for inputting steel member design data, refer to "Steel member input methods".

544

Steel Member Design

Steel member input datasheet This tool allows you to graphically edit steel design members (also known as "design groups") that were previously defined using the "Auto-create steel members" and/or "Steel member input form" tools. You can access the steel member input datasheet by selecting "Steel Member Design InputDatasheet" from the Design menu or selecting some members and then "Steel Member Design Input (Datasheet)" from the floating menu. After you have selected one or more steel design members, click the right mouse button and select "Steel Member Design Input (Datasheet)" from the floating menu (or select "Ok" if you initiated the operation from the menu). For detailed information about the data in the datasheet, refer to "Steel member design data".

Refer to "Using datasheets" for information on how to operate the above datasheet. For an overview of the various methods available for inputting steel member design data, refer to "Steel member input methods".

545


Copy steel member properties This tool lets you copy the design properties of a steel design member (also known as a "design group") to a selection of destination steel design members. Note that the properties can only be copied to members that have already been set up as steel design members. The procedure is as follows. 1.

Select the source member that you wish to copy the properties of, click the right mouse button and then select "Copy Steel Member Properties" from the floating menu that appears. OR Select "Copy Steel Member Properties" from the Design menu and then select the source member that you wish to copy the properties of.

2.

Select one or more destination members by picking them individually or by putting a selection window around them and then click the right mouse button and click "Ok".

3.

The steel design properties of the source member will then be copied to the selected destination members.

4.

Select another source member, or press ESC or the right mouse button to exit from the tool.

After the copy, you should check the destination members to ensure that the effective lengths, flange restraints and other data are appropriate. In particular, check that the effective lengths are correct and that the flange restraints are not located off the ends of the steel design member. For an overview of the various methods available for inputting steel member design data, refer to "Steel member input methods".

546

Steel Member Design

Steel member design data This section describes the steel member design data that is required to be input before you can design and/or check steel members that are part of a frame analysis model. For an overview of the various methods available for inputting steel member design data, refer to "Steel member input methods".

The form that appears when you input steel member design data graphically is shown above. The steel member datasheet contains the same information in a different format. Group Each steel design member is made up of one or more analysis members. Hence, the concept of steel design groups is introduced. A steel design group usually represents a single piece of steel in the real structure. It could be modelled as a single member or a number of members in the analysis model.

547


In order to make it easier to relate member numbers to group numbers, it is often a good idea to give the design group the same number as the first member in the group. Otherwise, there is sometimes a tendency to confuse member numbers and group numbers when scanning the design output data. By default, SPACE GASS will give a design group a number corresponding to the first of the members selected (when performing a graphical steel frame data input). You can, of course, change this if you wish. Description An optional brief description of the steel design group. Member list A list of analysis members to be combined into the steel design group. This is often only one member in each group. Because the top flange for a steel design group is taken to be the same as the top flange for the first member in the design group, it is important to control which member comes first in the design group. Flange restraint positions are also referenced from the end of the first member in the design group. See also Member groups. Strength grade The strength grade for members can be set to normal or high. The actual yield strengths are taken from the standard section libraries supplied with SPACE GASS. All of these libraries can be viewed or edited (see also Section libraries). Choices are:

Normal, High.

Units The compression effective lengths and flange restraint positions can be specified as actual distances or as ratios of the design group length. Choices are:

Actual, Ratio.

Load height position The load height position is used to allow for the case when a member is subjected to a downwards load acting above its shear centre causing an increased tendency for the flange to buckle laterally (out-of-plane). The load height position can be set to "Top flange" if this occurs, or "Shear centre" if the predominant load is positioned at the shear centre or below such that it resists lateral buckling of the flange. Choices are:

Shear centre, Top flange.

The load height position affects the value of the load height factor kl which is used to calculate the bending effective length of the member.

548

Steel Member Design

Destabilizing and stabilizing loads

See also Load height factor. Scan code In order to control the types of steel sections that the program selects during the course of a design, a library scan code is required. This allows you to select the types of sections that should only be considered for each member. For example, you could use it to tell the program that only I-sections were to be considered for the design of a portal frame column. Without the library scan code the program would simply choose the lightest adequate steel section from the library, regardless of its type or shape. The library scan code is simply a list of up to four characters that contains the group codes of sections that are to be considered during the design of a member. You can input the scan code directly or click the "Select" button and then choose the section types you require and the scan code will be created for you. Compression effective lengths (Lc major and minor) These are the effective lengths for overall buckling about the major and minor axes due to axial compression. Depending on the "Units" selected, the Lc values may be expressed as an absolute length or as a ratio of the total group length. Compression effective lengths can be calculated from a buckling analysis, however you can elect to input them directly if you prefer. To have them calculated, select the "Calculate from Buckling Analysis" check box. Of course to have Lc calculated, you must have the buckling analysis module (it is not a standard program feature) and you must run a buckling analysis before you can run the steel member design. Having the Lc values calculated automatically is generally more efficient than specifying them directly because case specific Lc values can be calculated for each design load case. However, the buckling analysis sometimes over-estimates the Lc values for members that are not directly involved in the buckling of the model (refer to "Overestimation of compression effective lengths" in Buckling effective lengths for further information). If you specify Lc values directly then they are used for every load case. If the Lc values are not being transferred automatically from a buckling analysis, for design groups that consist of a number of analysis members connected end-to-end, you should use the MAXIMUM (not the sum!) of its individual analysis member effective lengths.

549


The "Braced in Position at Both Ends of Group" check boxes indicate whether or not the group is braced for each of the major and minor axis directions. If you specify that the group is braced then its compression effective length in the direction you specify will not be allowed to exceed the overall group length, regardless of whether it was calculated from a buckling analysis or specified directly by you. Because this can substantially reduce the effective lengths used in the design, please use this option with care!

It is sometimes useful to model more than one structure in a single job, however this is not recommended if you are performing a buckling analysis to obtain compression effective lengths. The buckling analysis finds the lowest buckling load factor for the entire model and then calculates the effective lengths for all the members in the model based on that buckling load factor. For example, if you have modelled structure A and structure B in one job, and structure A has the lowest buckling load factor, the effective lengths for structure B will be incorrectly based on the buckling load factor from structure A. SPACE GASS can't detect if there are multiple structures in a single model and therefore you need to put them into separate jobs if you want to use effective lengths from a buckling analysis.

If the compression effective lengths are calculated from a buckling analysis, they are always taken from the first buckling mode regardless of how many buckling modes were calculated.

During the design phase, the compression effective lengths as calculated or defined by you may be adjusted depending on parameters you specify at the start of the design phase. For more information about this, refer to Running a steel member design.

For single angle sections, the compression effective lengths must be input relative to the non-principal axes. For AS4100, BS5950, NZS3404, AS4600, AISC-LRFD, AISC-ASD, HK CP2011, EUROCODE 3 and IS800, they are optionally converted to the principal axes during the design/check phase. To prevent this conversion, refer to Running a steel member design.

In order to cater for all design code naming conventions, the compression effective lengths are referred to as "Lc major" and "Lc minor" in this document and in the data entry parts of the program. However, in the design output reports, they are changed to match the notation of the design code that was used. See also Buckling effective lengths. Bending effective lengths (Lb +ve and –ve) Bending effective lengths for positive moments (Lb +ve) and for negative moments (Lb –ve) are normally calculated based on the flange restraints that you specify, however you can elect to input them directly if you prefer. To have them calculated, select the "Calculate from Flange Restraints" check box. During the design, if you have elected to have the bending effective length calculated, it is taken as the length of the segment under consideration multiplied by three additional factors

550

Steel Member Design kt twist factor), kl (load height factor) and kr (lateral rotation factor) such that Lb = Lseg x kt x kl x kr. Alternatively, if you have specified the bending effective length directly then the specified value is used without modification. kt, kl and kr are fully explained in AS4100/NZS3404 clause 5.6.3. In AS1250, SABS0162, BS5950, AS3990, HK CP2011 and EUROCODE 3 there are no kt kl and kr factors and so SPACE GASS uses the rules of AS1250 clause 5.9, SABS0162 clause 7.2.3, BS5950 clause 4.3.5, AS3990 clause 5.9, HK CP2011 clause 8.3.4 or EUROCODE 3 clause F.1.2 to calculate equivalent kt, kl and kr factors which, when multiplied together, produce an overall effective length factor kb.

Because the steel member design module can't detect if the member being designed is a cantilever or not, it is recommended that for cantilevers (for which the critical flange may be the tension flange) you check that the calculated bending effective length is correct and, if not, specify it manually.

S In order to cater for all design code naming conventions, the bending effective length is referred to as "Lb" in this document and in the data entry parts of the program. However, in the design output reports, it is changed to match the notation of the design code that was used. ee also Twist factor. See also Load height factor. See also Lateral rotation factor. Indian seismic checks (IS800 chapter 12) Seismic checks for IS800 were added in SPACE GASS 12.27.368. In order to activate these checks for a particular steel member you must specify its seismic classification as an ordinary concentrically braced frame (OCBF), special concentrically braced frame (SCBF), ordinary moment frame (OMF) or special moment frame (SMF), and member type as beam, column, brace or non-specific. The following IS800 code clauses are checked: Clause 12.3 and table 23 - All member types. Clause 12.2.3 - Columns. Clause 12.5.1 - Columns. Clause 12.5.1.1 - Columns. Clause 12.7.1.1 - All member types. Clause 12.7.2.1 - Braces. Clause 12.7.2.2 - Braces. Clause 12.7.2.4 - Braces. Clause 12.7.2.6 - Braces. Clause 12.8.1.1 - All member types. Clause 12.8.2.1 - Braces. Clause 12.8.2.2 - Braces. Clause 12.8.2.3 - Braces. Clause 12.8.2.5 - Braces. Clause 12.8.2.7 - Braces. Clause 12.8.4.1 - Columns. Clause 12.10.1.1 - All member types. Clause 12.11.1 (steel grade check only) - All member types. Clause 12.11.1.1 - All member types. 551


For a "Non-seismic" member classification, none of the above checks are performed. For a "Non-specific" member type (with OCBF, SCBF, OMF or SMF classification), only the "All member types" checks are performed. The checks for "E250B steel of IS2062 only" in clauses 12.8.2.1 and 12.11.1 simply look for a yield stress of between 230MPa and 250MPa and an ultimate stress of 410MPa. Because these yield and ultimate stress properties apply equally to E250A, E205B and E250C steel, and because SPACE GASS can't detect the difference between them, it is up to the user to ensure that E250A and E250C steel is not used when clauses 12.8.2.1 or 12.11.1 apply. It is up to the user to create the load combinations in clause 12.2.3 and include them in the list of load cases to be considered in the design/check. The IS800 module will identify the clause 12.2.3 load combinations SOLELY by the presence of a multiplying factor of 2.5 and will use those load combinations for columns ONLY if clause 12.5.1 is satisfied. Any load combinations containing a multiplying factor of 2.5 will only be used if they are included in the list of load cases to be considered, seismic checks are activated, and clause 12.5.1 for columns is satisfied. Furthermore, only their axial forces will be considered.

New Zealand seismic checks (NZS3404 chapter 12) Seismic checks for NZS3404 were added in SPACE GASS 12.20.205. In order to activate these checks for a particular steel member you must specify its seismic classification as category 1, 2, 3 or 4, and member type as beam, column, brace or non-specific. The following NZS3404 code clauses are checked: Table 12.4 (items 1 and 3) - All member types. Clause 12.4.1.2 - All member types. Clause 12.5.2 - All member types. Clause 12.5.3.1 - Braces. Table 12.5 - All member types. Clause 12.7.2.1 - Beams. Clause 12.8.3.1(a) - Columns and braces. Clause 12.8.3.1(b) - Columns. Clause 12.8.3.1(c) - Columns and braces. Clause 12.10.3.1 - Beams. For a "Non-seismic" member classification, none of the above checks are performed. For a "Non-specific" member type (with category 1-4 classification), all of the above checks are performed. Note that the item 1 check in NZS3404 Table 12.4 uses the actual yield stress rather than the 12 < t <= 20 mm grade reference yield stress. Flange restraints Flange restraint positions are referenced from the end of the first member in a design group. SPACE GASS assumes that there is a restraint at each end of a group and you should therefore specify the intermediate restraint positions only. Restraint positions should be specified independently for the top and bottom flanges. Up to 100 intermediate positions can be specified for each flange. If there are no intermediate restraints for a particular flange then the restraint positions field should be left blank.

552

Steel Member Design When specifying restraint positions, you can use @’s to specify relative positions or groups of equally spaced positions. For example, restraint positions of 1.2,2.4,3.6,4.8,6.0,6.6,7.2,7.8,8.4 could be specified as [email protected],[email protected], or positions of 1.2,1.8,2.7,3.3 could be specified as 1.2,[email protected],2.7,[email protected]. Depending on the "Units" selected, the restraint positions may be expressed as an absolute distance or as a ratio of the total group length. Flange restraint types must be specified for each intermediate restraint position and for the two ends of the design group. Refer to "Flange restraints" for restraint definitions. Choices are:

Full (F) Partial (P) Lateral (L) Full and rotational (R) Partial and rotational (S) Unrestrained at end (U) Continuous lateral restraint (C) Ignore segment (I)

The top flange of a member is the flange on the positive local y-axis (or z-axis if the section has been flipped) side of the member. The top flange of a group as a whole is defined such that it is the same as the top flange of the first member in the group. You can verify graphically which is the top flange by clicking the button near the bottom of the side toolbar. It displays a small triangle that points to the top flange of each member.

For single angle sections, flange restraints must be input relative to the non-principal axes. For AS4100, BS5950, NZS3404, AS4600, AISC-LRFD and AISC-ASD, they are converted to the principal axes during the design/check phase. See also Flange restraints. See also Effective flange restraints. Consider eccentric effects For members that have eccentric end connections, you can elect to consider or ignore the resulting eccentric moments. Eccentric moments are only added if they increase the normal design moments. Note that even if you select this check box, you can disable eccentric effects globally by deselecting the eccentric effects check box in the steel member design/check form. Maximum bolts in cross section In order to calculate the effective web and flange areas, and subsequent member capacities, the presence of bolt holes at the member ends must be taken into account. SPACE GASS requires you to estimate the number and diameter of bolts per cross section at the ends of each member to be designed or checked. A bolt count of zero indicates that the member end is welded. During the design, SPACE GASS checks to see that the bolts per cross section specified can be fitted into the cross section. If not, the number is reduced to the maximum that can be 553

SPACE GASS 12 User Manual accommodated. If the member is too small to take even a single bolt then the connection is assumed to be welded. Bolt diameter End connection bolt diameter. Angle type In order to define the geometry of single or double angle sections, SPACE GASS requires the angle section type to be input. Choices are:

Single angle, Double angle with short legs connected, Double angle with long legs connected, Double angle starred (equal angles only).

Double angle sections are assumed to have no space between the individual angle sections. ! IMPORTANT NOTE ! The AS1250, SABS0162 and AS3990 modules assume that double angles are connected together at intermediate points sufficient to ensure that half of the design axial compressive force for the combined section does not exceed the compressive capacity of each angle section considered individually using an effective length (for buckling of the sections away from each other) equal to the distance between connection points. The AISC-LRFD, EUROCODE 3, AS4100, NZS3404, BS5950 and HK CP2011 modules convert double angle sections into the equivalent Tee section and then treat them as a solid Tee shape. They do not support double starred angles.

554

Steel Member Design Angle section orientation

All of the possible arrangements involving single and double angles are shown in the diagrams above. It is important to note that the major axis of a single or double angle section is assumed to be parallel to the short leg(s) of the section as shown in the diagrams.

For double equal angles, the long leg is assumed to be the vertical leg in the diagrams above. Note that in SPACE GASS 10 and earlier, double equal angle sections with long legs connected were adjusted internally and treated as though their short legs were connected. This adjustment was removed in SPACE GASS 11 and later versions. The design procedure for angle sections is considerably more complicated than for most other sections. This is due to the significant moments generated by eccentric end connections which cannot usually be avoided when working with angles. SPACE GASS is capable of taking these effects into account for both single and double angle sections.

When designing/checking single or double angle sections for AS1250, SABS0162 or AS3990, SPACE GASS considers only axial forces and shears. Normal bending moments are not considered. The only moments considered are those due to the eccentric end connections. This is not the case with the other design modules. They consider all axial forces, shears and moments together with any extra eccentric moments (if appropriate). Furthermore, for single angle sections, the effective lengths and flange restraints must be input relative to the non-principal axes. For AS4100, BS5950, NZS3404, AS4600, AISCLRFD and AISC-ASD, they are converted to the principal axes during the design/check phase. End connection For non-symmetric members subjected to axial loads, such as angle sections, channels and Tees, the program needs to know which leg, flange or web is connected so that the extra moments due to possible eccentric end connections can be calculated (if appropriate). Choices are:

Concentric, Flange(s) (for I, H, T or channel sections), Web (for channel or T sections), Angle short leg, Angle long leg (vertical leg for equal angles before being flipped or a direction angle, direction node or direction axis applied).

Design criteria Most designs aim to minimize the structure weight, however if you are constrained to a certain member depth then you can elect to minimize the member depth instead. Choices are:

Weight, Depth.

Use Previous button Click the "Use Previous" button to set all the data in the form to the same as when the form was previously used. 555


See also Steel member input methods. See also Steel member design text. See also Running a steel member design.

556

Steel Member Design

Steel member design sign conventions The steel member design module deals only with the member cross section axes. The longitudinal axis of the member is of no relevance. For most section types, steel member design input and output data always relates to the major and minor principal cross section axes. The only exception is for single angle sections where the effective lengths and flange restraints must be input relative to the non-principal axes (the axes parallel to the angle legs) for all design codes. During the design phase, the data for single angle sections is converted to the principal axes for AS4100, BS5950, NZS3404, AS4600, AISC-LRFD and AISC-ASD. Output reports for those codes also show the data in principal axes for single angle sections. See also Column and beam Tees.

557


Member groups In a typical structure, the actual beams, columns, struts, ties, etc. are modelled in SPACE GASS as members connected together at nodes. Sometimes, however it is convenient and often necessary for members to have nodes placed at intermediate positions along them so that they are subdivided into smaller members. This can occur when another member intersects a member at an intermediate point or when a node is simply placed at an intermediate point so that deflections, forces and moments are calculated at that point during the analysis. Quite often the placement of intermediate nodes along a member is done purely for frame analysis modelling purposes rather than due to an actual discontinuity or connection in the real structure. For this reason, SPACE GASS allows you to group frame analysis members together and design them as though they are a single entity (as they are in the real structure). In the remainder of this manual a "design group" represents an actual member in the real structure which consists of one or more frame analysis members grouped together end-to-end.

Note that in the following discussion, members in a group can be listed in either direction. For example, "1,3,8,5" and "5,8,3,1" are both suitable. The direction can, however affect the definition of the top flange (see also Flange restraints). Consider, for example, a simply supported beam with a node at each end which is subjected to an axial compressive force and a uniformly distributed dead load. When analysed, the deflected shape and bending moment distribution along its length is calculated by SPACE GASS. If the structural adequacy of this member is then checked against one of the design codes, various factors are calculated based on the deflected shape and the bending moment distribution. These factors are then used in the calculations to determine if the member is adequate or not. If the same beam is modelled with a third node at midspan, you would still get the same deflected shape and bending moment distribution, however unless you were able to group the two halves of the beam together and design them as though they were a single member you would get a completely different design result. This is because the factors and the combined actions moments and axial forces would be based on the deflection and moment distributions for only half of the beam rather than its full length.

If a member has been subdivided into smaller members in the analysis model, it is important that these sub-members are grouped together in the design model. The rules for deciding whether or not a run of frame analysis members should be grouped into a design group are as follows. 1.

Each member in a design group must be rigidly connected to each other end-to-end, they must lie generally in a straight line, and they must have the same section properties.

2.

The length of a design group should not be less than the major axis span.

3.

A design group must be long enough to include all of the flange restraints that affect its bending effective lengths. Furthermore, under no circumstances should the design group

558

Steel Member Design length be less than the unrestrained lengths of the top and bottom flanges. This rule is not applicable if the bending effective lengths are specified directly rather than being calculated. 4.

Each end of a design group should coincide with the physical end of a member or a significant change in direction of a member, or a support point for a member. It shouldn’t normally extend past a support or past an intersecting member that effectively acts as a support. "Support" refers to a support for the major axis span.

If it is not possible for all of the above rules to be satisfied then you should not use SPACE GASS to design the steel members involved. Consider the following examples, indicating how members in typical frames can be grouped together.

Member grouping for gable portal

Group 1: Group 2: Group 3: Group 4:

1,2 3,4,5 6 7,8

Member grouping for flat portal

Group 1: Group 2: Group 3:

1,2 3,4,5,6 7,8

559


Member grouping for truss

Group 1: 2,6,10,14,18,22 Group 2: 4,8,12,16,20,24 Group 3: 1 Group 4: 3 (Some of the non-critical members have not been grouped) ! IMPORTANT NOTE ! The above grouping assumes that local bending of the chords between panel points is insignificant compared with overall bending between the end supports (ie. the panel points are not really acting as support points for the chords). If the chords were effectively spanning L/6 instead of L then the chord members could not be grouped.

Member grouping for multi-storey frame

Group 1: Group 2: Group 3: Group 4: Group 5: Group n: etc...

560

1 2 3 4 5 n

Steel Member Design No grouping of multiple members can occur in this case because each member acts as a single span. The horizontal beams act as supports for the columns at each floor and the columns act as supports for the beams. Note that, if there was no significant axial forces in the beams such that they were not acting as supports for the columns then the columns could be grouped into one design group from bottom to top. This would not, however be a common situation.

Member grouping for continuous beam

Group 1: Group 2:

1,2,3,4 5,6

561


Flange restraints Flange restraints must be specified for both top and bottom flanges at each end of a design group and at each intermediate restraint position.

Because the positions of the start and finish flange restraints is known, only the intermediate restraint positions should be specified. However, the end and intermediate restraint types should be specified. The top flange of a member is the flange on the positive local y-axis (or z-axis if the section has been flipped) side of the member. The top flange of a group as a whole is defined such that it is the same as the top flange of the first member in the group. You can verify graphically which is the top flange by clicking the button near the bottom of the side toolbar. It displays a small triangle that points to the top flange of each member. There are two classes of restraint types; those that occur at a discrete point and those that occur over a continuous length of flange between two point restraints. The number of point restraint types should exactly match the number of restraint positions. When @ multipliers are used in the restraint positions lists, the corresponding restraint types must have only one character for each @ multiplier. For example, restraint positions of 1.2,2.4,3.6,4.8,6.0,6.6,7.2,7.8,8.4 with corresponding restraint types of LLLLLPPPP could be specified as [email protected],[email protected] and LP. If the restraint types were LLPLLPPPP, however then they would have to be specified as [email protected],3.6,[email protected],[email protected] and LPLP. SPACE GASS accepts six point flange restraint types and two continuous flange restraint types. They are defined as follows. Note that these definitions are slightly different to the ones in the design codes because the code definitions apply to the cross section rather than to each flange. The cross section restraints are determined from the flange restraints during the design or check phase. Full restraint (F)

Prevents lateral deflection of the flange to which it is applied and fully prevents twist rotation of the section.

Partial restraint (P)

Prevents lateral deflection of the flange to which it is applied and partially prevents twist rotation of the section.

Lateral restraint (L)

Prevents lateral deflection of the flange to which it is applied but is ineffective in preventing twist rotation of the section. A lateral restraint can only be considered to be effective when it is positioned between full or partial restraints.

Full & rotational restraint (R)

The same as full restraint above but also with significant restraint against lateral rotation of the flange about the

562

Steel Member Design cross section’s minor axis. Partial & rotational restraint (S)

The same as partial restraint above but also with significant restraint against lateral rotation of the flange about the cross section’s minor axis.

Unrestrained (U)

There is no resistance to lateral deflection of the flange to which it is applied or twist rotation of the section. This can only be used at the end of a design group.

An "unrestrained" end does not necessarily imply a cantilever. Flange restraints are independent of the member support system. Cantilevers or beams with supported ends could be restrained or unrestrained. The following flange restraint types do not occur at a point but are continuous between two adjacent point flange restraints. Continuous lateral restraint (C)

Prevents lateral deflection of the flange to which it is applied but is ineffective in preventing twist rotation of the section. A continuous lateral restraint can only be considered to be effective when it is positioned between full or partial restraints.

Ignore segment (I)

This is not really a flange restraint, rather it instructs SPACE GASS to skip past the ignored segment length when designing or checking. It can be used very conveniently to ignore the very rigid area where intersecting members connect so that members are designed from the face of intersecting members rather than from their centrelines. It is also very handy for when a member is stiffened over part of its length and is not required to be designed over that portion.

The above definitions allow for full, partial, lateral or no restraint against twist of the cross section (about its longitudinal axis) (F,P,L,C or U). They also allow for full or no restraint against lateral rotation of the critical flange (about the minor cross section axis) in the presence of full or partial twist restraint (R or S). An extra restraint condition which is catered for in AS1250, SABS0162, BS5950, AS3990 and HK CP2011 only, that provides partial restraint against lateral rotation of the critical flange is not supported by SPACE GASS.

For single angle sections, it is unclear whether or not lateral restraints applied to either leg are effective in providing any restraint to the section. Consequently, you should be very careful when applying lateral restraints to single angle sections and you should use

563

SPACE GASS 12 User Manual them only if you are sure they are effective in restraining the section. SPACE GASS will apply them if you specify them and so the decision about whether or not they should be used is entirely up to you. Note that the design/check calculations are based on the effective cross section restraint rather than the restraint on a particular flange. The effective cross section restraint depends on which flange is the critical one and on what flange restraints are applied to the critical and the non-critical flanges. Refer to "Effective flange restraints" for more information. The following diagrams are a collection of some fairly typical support and fly brace connection details. The type of restraint that applies to each flange is shown as either "full", "partial", "lateral" or "unrestrained". Note that the diagrams apply regardless of whether or not rotational restraints also exists. The terms "full" or "partial" could also read "full and rotational" or "partial and rotational" in each of the diagrams.

564

Steel Member Design

Flange restraint types

Consider, for example, the portal frame below. The roof bracing system laterally braces each rafter at the eaves and apex. Purlins are positioned at ninth points along each rafter and fly braces are attached to each third purlin at rafter third points. Girts are positioned at the midheight of each column.

565


Portal frame flange restraints

We will assume that the roof sheeting has enough rigidity to allow the purlins to prevent lateral deflection of the rafter top flange. Note that if the roof sheeting has insufficient rigidity to prevent lateral deflection then the fly braces will not be capable of providing any restraint to the bottom flange and will thus be totally ineffective. The frame could be set up with four design groups, each containing the following members. Group 1: Group 3: Group 6: Group 7:

1,2 3,4,5 6 7,8

When determining flange restraint positions and types, we will assume that the footing, eave and apex connections provide F (full) restraint to both flanges of each member framing into them. There is no fly bracing attached to the wall girts and they provide lateral restraint only to the outside flange of the columns. Thus, groups 1 and 7 have top flange restraints of F (full) at each end and L (lateral) at mid height, and bottom flange restraints of F (full) at each end only. If there had been fly bracing to the girts then there would also be a bottom flange mid height restraint of L (lateral). Note that the top flange for groups 1 and 7 is the outside flange because the local y-axis for members 1, 2, 7 and 8 points towards the outside of the frame.

566

Steel Member Design Similarly, groups 3 and 6 have top flange restraints of F (full) at each end and L (lateral) at each purlin, and bottom flange restraints of F (full) at each end and L (lateral) at each fly brace location. Thus, the restraint arrangements for the frame are: Groups 1 and 7: FLF FF Groups 3 and 6: FLLLLLLLLF FLLF

(Outside flange) (Inside flange) (Top flange) (Bottom flange)

Note that by applying L (lateral) restraints to both flanges at each fly brace location we are assuming that the purlins are flexurally stiff enough to fully prevent twist rotation of the rafter. If they can only partially prevent twist rotation of the rafter then the group 3 and 6 restraints would become FLLPLLPLLF on the top flange and FF on the bottom flange. Restraint Forces The brace, purlin, girt or other member that provides full, partial or lateral restraint to the critical flange of a member must be capable of resisting the force required to provide such restraint. This is not automatically allowed for in the analysis or design. If you wish to take this into account then you should add the restraint forces to your applied loads. The restraint forces are code specific and you should refer to the appropriate clauses for the design code you are using. This effect is particularly important for deep beams where the forces required to restrain the critical flange can be quite high. You should check that your model is capable of withstanding these forces.

567


Column and beam Tees Column Tees have the major axis parallel to the web and are therefore assumed to be lying on their side with their flange vertical (assuming a zero direction angle and no flipping). They are orientated at right angles to normal beam Tees which have the major axis parallel to the flange.

Tee section orientation

Note that although beam Tees are supported by all of the steel member design modules, only the AS4100, NZS3404, AISC-ASD, AISC-LRFD, EUROCODE 3, HK CP2011 and BS5950 modules support column Tees. See also Steel member design sign conventions.

568

Steel Member Design

Running a steel member design You can run a steel member design or check by selecting one of the "Steel Member Design/Check" items from the Design menu.

Limit state codes such as AISC-LRFD, EUROCODE 3, AS4100, NZS3404, BS5950 and HK CP2011 require second order effects to be taken into account by either performing a first order (linear) elastic analysis with moment magnification or a second order (nonlinear) elastic analysis with no moment magnification. Because a non-linear analysis is generally more efficient and accurate than moment magnification, and because SPACE GASS has no facilities for moment magnification, it is recommended that a non-linear analysis be used at all times for these codes. Design / Check mode You can select between design mode or check mode as follows. 1. Design mode Works its way up from the smallest library section that conforms with the specified library scan code until it finds a section that passes the code requirements for the design group being designed.

2. Check mode Just checks the section from the analysis data for the design group being checked. Note that SPACE GASS can now do a steel member check using sections that haven't been imported from a library, however you must have specified their steel design properties via the Shape builder. Member groups list If you want to consider all design groups (for which steel member design data has been input) then this field can be left blank, otherwise you should type in a subset of design groups (separated by commas or dashes).

569


Section properties list If you want to consider all design groups (or a subset as specified above), regardless of section type, leave this field blank. Otherwise, type in a list of section property numbers (separated by commas or dashes) to limit the number of design groups. For example, if the columns in a frame all have section property number 3, you could instruct the program to design only the columns by entering "3" in the section properties list. Alternatively, you could type in all of the groups containing columns in the member groups list above, however this would be much more cumbersome. Load cases list If you want to consider all load cases then this field can be left blank, otherwise you should type in a list of incorporating the load cases (separated by commas or dashes) that you want considered. Default section library During the frame analysis section property input phase, sections that are read from a library have the library name stored with their section property data. Sections that have not been read from a library do not have a library name stored with their data. For members with analysis section properties that were read from a library, the steel member design module uses that library to get information about the strength grade, properties, cross section shape, etc. of the member. For members with analysis section properties that were not read from a library, the design module uses the default section library to get its information. Intermediate stations per member During the design process, each analysis member in a design group is subdivided into small increments using intermediate member stations. You must define the number of equally spaced intermediate stations that are to be positioned along each analysis member. SPACE GASS automatically adds an extra station at each end of an analysis member, at each point of application of a concentrated member load, at each flange restraint position, and at the quarter points between flange restraints. If a design group consists of more than one analysis member then the member stations are simply added together to give a total number of stations for the design group as a whole. The member stations are the points at which deflections, forces and moments are calculated. They are also the points at which code checks are carried out. It is therefore important that there are enough stations located along the design group to give a good representation of the deflected shape, bending moment diagram and shear force diagram so that the design results are accurate. 9 intermediate stations for each analysis member is normally quite accurate, however this can be increased to 75 if required. Note that the speed of the design process is approximately proportional to the number of stations per design group. Compression effective length ratio limit Because the compression effective lengths from a buckling analysis can sometimes be overestimated, you can specify an upper limit that will be imposed during the design phase.

570

Steel Member Design Compression effective lengths from a buckling analysis are limited to Ratio x GLen, where Ratio is the compression effective length ratio limit that you specify and GLen is the overall design group length. Note that this limit applies only to compression effective lengths from a buckling analysis and not to those specified directly. See also Buckling effective lengths. Load factor limit or Combined stress ratio limit Firstly, the terms "load factor" and "combined stress ratio" are defined as follows. The load factor applies to all limit state codes such as AISC-LRFD, EUROCODE 3, AS4100, AS4600, BS5950, NZS3404 and HK CP2011. It is the amount by which the design actions can be increased before the point of failure is reached. For example, if the steel design returns a load factor of 1.12, you could theoretically increase your loads by 12%, repeat the analysis and design, and expect the load factor to reduce to 1.00. This is not always the case however, because the non-linearity of the analysis means that increasing your loads by 12% does not guarantee that the design actions will also increase by exactly 12%. For members designed in accordance with these codes, the load factor must be greater than 1.0. This means that the design actions can be factored up by an amount greater than 1.0 before the member becomes inadequate.

Because the relationship between design actions and design capacity is not linear, the load factor is not equal to the inverse of the (design actions)/(design capacity) failure equation at the end of the detailed calculations for each member in the steel design report. The combined stress ratio applies only to AISC-ASD, AS1250, SABS0162 and AS3990. It is the ratio of the actual stresses to the permissible stresses for the governing combined stress equation. For members designed in accordance with AISC-ASD, AS1250, SABS0162 or AS3990, the combined stress ratio must be less than 1.0. This means that the combined stresses in the member are less than the combined permissible stresses. During the design process, if the load factor is slightly less than 1.0 or if the combined stress ratio is slightly greater than 1.0, the member is deemed to have failed. In a real design situation however, you may decide to accept members which are very slightly overloaded. In order to cater for this reality, SPACE GASS allows you to decrease the load factor limit or increase the combined stress ratio limit so that the design program can accept a small amount of overload. Alternatively, you can increase the load factor limit or decrease the combined stress ratio limit if you wish to design conservatively. Slenderness ratio limit This setting affects a simple slenderness ratio check that is only applicable to AISC-ASD, AISC-LRFD, AS1250, AS3990 and SA0162. The other codes have more sophisticated slenderness checks built into their standard equations.

571

SPACE GASS 12 User Manual For the applicable design codes, recommendations for maximum slenderness ratios range from 180 to 300 for struts, 300 to 350 for ties and 250 to 300 for beams. The maximum values depend on various factors including whether the predominant load is due to wind or not. For tension members and members that have zero axial load, there is no slenderness check for compression effective lengths, however there is a slenderness check for bending effective lengths. Because of this, you may notice that in some cases the output report shows a value of l/r (compression) which exceeds the permissible l/r ratio without the member failing. Interrupted check (check mode only) If the checking procedure is uninterrupted, then after each member check, the results are saved and the program moves on to the next member regardless of the outcome of the check. Using this procedure, it is possible to check a large numbers of members without any operator intervention. Alternatively, you can elect to have interrupted checking which causes the program to stop after each member check, notifying you of the results of the check and allowing you to manually select other member sizes for checking. If you decide not to try other member sizes, the program saves the results of the check and moves on to the next member. Equalizing the design sizes for matching analysis sections SPACE GASS allows you to specify that all members with the same analysis section property number should finish up with the same section size in the design results. Note that this only applies to running the steel member design module in "design" mode. For example, consider a portal frame with one analysis section for the two columns and another for the two rafters. When you perform a steel member design (as opposed to a check), you can specify that because the two columns share the same analysis section property number, their final design sizes should also match. Similarly, the two rafters can also be kept equal on each side because they share a single analysis section property number. If this option is not selected, the design module will design each member independently rather than matching a single section size to all members that share the same analysis section property number. For the portal frame example mentioned above, this could results in four different member sizes rather than two. Adjustment of minor axis compression effective lengths Flange restraints capable of preventing lateral buckling of the flanges are sometimes also capable of preventing lateral buckling of the overall cross section. This depends on the type of the flange restraint and on the shape of the cross section and, if applicable, means that the minor compression effective length can be reduced to the length of the segment under consideration. This happens regardless of whether the compression effective lengths are calculated from a buckling analysis or specified directly. If you select the "Adjust based on flange restraints generally" check box, the minor compression effective length will be adjusted if: a. both ends of the segment have full or partial flange restraints; or

b. both ends of the segment have full, partial or lateral flange restraints and the member is a tube or box section. If you also select the "Adjust for L restraints on equal flanged I or W shapes" check box then condition (b) above will also be extended to apply to equal flanged I or W shapes. Note, 572

Steel Member Design however, that there is some recent doubt as to whether lateral restraints on equal flanged I or W shapes can restrain the overall cross section laterally and therefore this check box defaults to off. See also Buckling effective lengths. Consider eccentric effects Members such as angles, channels and Tees are sometimes connected at their ends by one flange or plate only. Depending on the shape of the section and the distance from the point of connection to the centroid of the section this can induce eccentric moments into the member. This check box only affects the design groups that have eccentric effects enabled in their design input data. For design groups that have their individual eccentric effects disabled, this check box setting has no effect. See also Eccentric effects for compression members. See also Eccentric effects for tension members. Convert single angle compression effective lengths For single angle sections, the compression effective lengths must be input relative to the nonprincipal axes. These lengths are normally converted to principal axes during the design phase if required, however you can prevent this by unticking the "Convert single angle compression effective lengths" option. One reason for this might be that you have already input the compression effective lengths in principal axes and you don't want them to be converted. Use Kt factor for tension members When considering eccentric end connection effects, the extra eccentric moments are usually calculated and then added to the other bending moments in the member. For tension members with AS4100/NZS3404, however the code allows you to use the above approach or simply ignore the extra eccentric moments and apply a correction factor (Kt) which is based on the cross section shape and the location of the point of connection (see AS4100/NZS3404 clause 7.3.2). By default the steel member design module defaults to using the Kt factor because it tends to give a more economical design in most cases, however you can elect to use the eccentric moments approach instead if you wish. See also Eccentric effects for tension members. Other factors Various other factors can also be defined depending on the design code being used. They include AISC-ASD and AISC-LRFD U and Cb factors, Eurocode UK and Dutch factors, an AS4600 appendix F switch and HK CP2011 mLT factors.

The HK CP2011 module also allows you to choose between using clause 8.9.2 or clause 6.8.3. If you choose clause 8.9.2 then the analysis does not need to include initial member imperfections or P- effects because they are accounted for in the design phase (although it may be prudent for you to use both P- and P- effects in the analysis anyway). Alternatively, if you choose clause 6.8.3 then you must include initial member imperfections and both P- and P- effects in the analysis.

573

SPACE GASS 12 User Manual Frame and Member Imperfections Most design codes require you to include initial frame and member imperfections in the analysis. The analysis module does not do this automatically and so you must build the required imperfections into your model. Frame imperfections can be modelled by applying notional horizontal forces or initial deflections to nodes. Member imperfections can be modelled by applying initial curvature to members. These must both be done in accordance with the relevant clauses of the design code you are using.

When all of the information has been entered, the SPACE GASS steel member design/check proceeds. If you want to terminate the process before it is finished, just press ESC or the right mouse button. If you terminate the process in this way, the results for any groups that have already been designed or checked are saved.

574

Steel Member Design

Updating analysis member sizes The accuracy of any steel member design is dependent on the accuracy of the analysis on which it was based. A truly accurate design can only be obtained when the design member sizes agree with those used in the preceding analysis. SPACE GASS has the ability to iterate the analysis-design process until the results converge. The design sizes can then be printed out and used in the final computations. You can access the updating tool by answering "Yes" to the "Do you wish to update the analysis section properties with the new design member sizes?" question at the end of a steel member design or by selecting "Update Analysis Member Sizes" from the Design menu. Note that this tool only works if you have run the steel member design module in design mode (as opposed to check mode).

After an initial design, you can use this tool to update the analysis section property data based on the new design member sizes. You can also re-run the analysis and design modules, and automatically iterate the entire update-analysis-design process until the analysis and design member sizes match. If a buckling analysis is included in the iterative procedure, after the update-analysis-design procedure has finished, if the lowest buckling load factor is less than the value you specify in the above form, a warning is given. Keep in mind that you may want to adjust the buckling load factor warning threshold depending on whether you are analysing working loads or factored loads.

The iterative procedure does not currently include re-running the dynamic analysis modules. Hence, if your steel member design is based on some dynamic spectral response analysis results, you must re-run the dynamic analysis manually for each iteration.

575


Serviceability check The SPACE GASS steel member design module does not consider serviceability requirements other than slenderness effects during the course of a design or check. This is because there are numerous ways to limit excessive deflections, many of which require extensive engineering judgement. The only deflections that can easily be checked for adequacy by an automatic design program such as SPACE GASS are the local member deflections that apply to each member individually. It is quite appropriate to check local member deflections for simple beams and columns, however for sway frames and for members that have been subdivided into smaller segments, the local member deflections become meaningless. Take for example a portal frame building that is found to have excessive lateral sway deflections. The deflections could be reduced in many ways such as by increasing the size of the columns, increasing the size of the rafters, introducing a haunch, increasing the size of the haunch, adding extra roof and end wall bracing or by adding an external restraint such as brickwork. The optimum method in controlling deflections is determined often by architectural constraints, cost constraints, engineering preferences and other constraints that are not immediately obvious to a design program. Some of these parameters could possibly be built into SPACE GASS, however the extra data required to be input would make the program very cumbersome and unwieldy compared to the method recommended in the following paragraph. In order to satisfy serviceability requirements, it is recommend that the frame first of all be designed to satisfy strength requirements. This includes the initial design and subsequent analysis-design iterations (see also Updating analysis member sizes). It is then a simple matter to obtain a graphical display or printout of the deformed geometry shape and simply observe whether the frame has excessive deflections or not. If the deflections are excessive, you can increase member sizes manually or add bracing as required, followed by another analysis and obtain a revised deformed geometry display. If the deflections are satisfactory it is then a matter of performing a final code check to ensure that the changes have not caused any members to become inadequate.

576

Steel Member Design

The steel member design/check process This section describes in detail the internal procedures and assumptions used as the program calculates the capacity of a design group and determines whether it is adequate or not. Because the procedure is very similar for all codes, you can assume that all of the discussion in this section applies equally to all codes unless specifically stated otherwise. The steps involved in a design are the same as those for a check except that a design tries various member sizes until it finds one that is adequate, while a check simply tries a single member size only and saves the results regardless of whether it is adequate or not. This process is repeated separately for each design group.

In the remainder of this section, the process of trying a member size for compliance with one of the steel codes will be referred to as "checking" regardless of whether it is done as part of a steel member design or a steel member check.

577


Design groups and intermediate stations The analysis members that make up the design group are assembled together into one complete design member. The intermediate member stations for each analysis member are positioned along the design group and then for each flange additional stations are positioned at the points of flange restraints and at quarter points between adjacent flange restraints. For each load case being considered, the deflections, forces and moments are calculated at each station along the entire design group. For single angle sections, they are calculated relative to the cross section principal axes for AS4100, BS5950, NZS3404, AS4600, AISCLRFD and AISC-ASD, and relative to the non-principal axes for AS1250, SABS0162, AS3990, EUROCODE 3 and HK CP2011.

578

Steel Member Design

Design segments The program begins working its way along the design group until it gets to the end of a segment. A segment end occurs at the start of the design group, at the end of the design group, and wherever a full, partial or lateral flange restraint has been applied to the critical flange. Thus the current design segment is the portion of the design group that extends from the current critical flange restraint location back to the end of the previous design segment (or start of the design group). For each station in the segment, the program does a cross section capacity check using the forces and moments which occur simultaneously at that point. It also does various member checks for the segment as a whole using all possible combinations of maximum forces and moments that occur anywhere in the segment.

579


Section check A section check simply considers the capacity of a cross section and is not related to effective lengths or any other conditions that occur away from the cross section. The forces and moments used are those which occur simultaneously at the cross section.

580

Steel Member Design

Member check A member check considers the capacity of a member segment. The member check is affected by the compression and bending effective lengths of the segment and the shape of the deflection and bending moment diagrams along the segment. The forces and moments used in a member check are the maximum values taken from anywhere along the segment.

581


Critical flange The critical flange at any point within a segment is assumed to be the compression flange unless either end of the segment is laterally unrestrained in which case it is assumed to be the tension flange.

Because the steel member design module can't detect if the member being designed is a cantilever or not, it is recommended that for cantilevers (for which the critical flange may be the tension flange) you check that the calculated bending effective length is correct and, if not, specify it manually.

SPACE GASS is not able to determine whether a loading condition is predominantly due to gravity or wind and you should therefore check that the above rule is valid for your situation. For more information refer to AS1250 clause 3.3.4.7, AS4100 clause 5.5, SABS0162 clause 7.2.3, BS5950 clause 4.3, NZS3404 clause 5.5, AS3990 clause 3.3.4.7 or HK CP2011 clause 8.3.

582

Steel Member Design

Effective flange restraints In the following discussion, the "segment length" is the distance between two adjacent cross sections that are restrained or between a cross section that is restrained and the end of the design group. A cross section is assumed to be restrained when a full or partial restraint is applied to either flange or when a lateral restraint is applied to its critical flange.

Member design segments

The design group in the diagram above consists of three analysis members of different lengths. The group has full or partial restraints at the ends and three equally spaced lateral restraints on the top flange. For the bending moment diagram shown, the first top flange lateral restraint is ineffective because the bottom flange is the critical flange at that point. Thus, the first segment continues past the first top flange restraint to midspan where the top flange has become the critical one. When determining the effective restraint at a cross section, SPACE GASS looks at the restraint applied to the critical flange, however it also looks at the other flange to see if a restraint has been applied to it and, if so, whether or not it affects the cross section restraint. Thus, the effective restraint for the cross section can be dependent on the restraint applied to both flanges. In the following table, the "critical flange" is as per the critical flange definition, the "other flange" is the non-critical flange and the "effective restraint" is the cross section restraint that SPACE GASS uses in the code check. For restraint type definitions see also Flange restraints. A C (continuous) flange restraint is assumed to be equivalent to a series of L (lateral) flange restraints spaced at increments of 1mm for the entire length of the continuous restraint. Restraint on Critical Flange None or U L P or F S or R None or U None or U None or U

Restraint on Other Flange Effective Restraint None or U None None or U L None or U F None or U R L None P or F P S or R S 583

SPACE GASS 12 User Manual L, P or F S or R

L, P, F, S or R L, P, F, S or R

F R

For single angle sections, it is unclear whether or not lateral restraints applied to either leg are effective in providing any restraint to the section. Consequently, you should be very careful when applying lateral restraints to single angle sections and you should use them only if you are sure they are effective in restraining the section. SPACE GASS will apply them if you specify them and so the decision about whether or not they should be used is entirely up to you.

584

Steel Member Design

Twist factor The twist factor kt depends upon the flange restraint conditions and the cross section shape. If the critical flange switches from top to bottom within the segment, the critical flange thickness is assumed to be the thickness of the flange at the end of the segment. For AS4100 and NZS3404, kt is calculated from table 5.6.3(1), while for AS1250, SABS0162, BS5950, HK CP2011, EUROCODE 3 and AS3990 it is taken as 1.0.

585


Load height factor The load height factor kl relates to the point of application of gravity loads as specified by the load height position (see also "Load height position" in Steel member design data). It is always 1.0 if the loads are applied at or below the member's shear centre, however for nonvertical members it can exceed 1.0 if the top of the member is subjected to a downwards load that causes a destabilizing effect.

If the top of the member is loaded within the segment then kl = 1.2 for all codes, except AS4100 and NZS3404 where kl = 1.4 if both ends of the segment are fully, partially or laterally restrained or kl = 2.0 if either end is unrestrained. If the top of the member is not loaded within the segment but shear force is detected at the end of a segment that is unrestrained then kl = 1.2 for all codes, except AS4100 and NZS3404 where kl = 2.0. If you specify the load height position as "Shear centre" then kl=1.0 regardless of the loading condition. For vertical members, kl=1.0 regardless of the load height position setting or the loading condition.

The definition of "top of the member" in the above discussion is the side or flange that is physically on top (ie. furthest from the ground). This definition is different to "top flange" used elsewhere in this manual which can actually be on the bottom if you have rotated the member about its own axis (eg. if the member is upside down).

586

Steel Member Design

Lateral rotation factor The lateral rotation factor kr is based solely on the flange restraint conditions. Its value for some codes is given in the following table. The restraint codes given represent the flange restraints at each end of the segment under consideration. For example, PP represents partial restraint at both ends, while PF represents partial restraint at one end and full restraint at the other end. End Restraints RR SR FR PR LR UR SS FS PS LS US FF PF LF UF PP LP UP LL UU

AS3990/ AS1250 0.70 0.77 0.85 .935 1.00 .935 0.84 .935 1.02 1.00 1.02 1.00 1.10 1.00 1.10 1.20 1.00 1.20 1.00 1.20

AS4100 0.70 0.70 0.85 0.85 1.00 1.00 0.70 0.85 0.85 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

SABS0162 0.70 0.77 0.85 .935 1.00 .935 0.84 .935 1.02 1.00 1.02 1.00 1.10 1.00 1.10 1.20 1.00 1.20 1.00 1.20

NZS3404 0.70 0.70 0.85 0.85 1.00 1.00 0.70 0.85 0.85 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

The values of kr in the table are taken from AS1250 clause 5.9, AS4100 table 5.6.3(3), SABS0162 clause 7.2.3, BS5950 clause 4.3.5, NZS3404 table 5.6.3(3) and AS3990 clause 5.9. There are some specific assumptions affecting kr which you should be aware of, as follows: 

AS1250, SABS0162, BS5950, HK CP2011 and AS3990 do not give specific rules for calculating kr for all combinations of flange restraints at the ends of the segment. In such cases interpolation has been used to calculate some of the values of kr given in the table.



The extra restraint condition in AS1250, SABS0162, BS5950, HK CP2011 and AS3990 which provides partial restraint against lateral rotation (about the cross section minor axis) of the critical flange is not supported in SPACE GASS.



Because it is difficult for SPACE GASS to determine whether a member is a true cantilever or not, AS1250 clause 5.9.4, SABS0162 clause 7.2.3(b), BS5950 clause 4.3.5.4/4.3.5.5, HK CP2011 clause 8..4.3 and AS3990 clause 5.9.4 have not been considered. This may cause the bending effective length for cantilevers to be underestimated and you should therefore check the bending effective length for cantilevers calculated by the AS1250, SABS0162, BS5950, HK CP2011 and AS3990 modules.

587


Before accepting the bending effective length calculated by SPACE GASS, it is recommended that you verify for yourself that the values of kr given in the previous table are a suitable interpretation of the code that you are using.

588

Steel Member Design

End moment ratios and other factors During a member check, various factors are calculated. In most cases, these factors are largely dependent on the moments at the ends of the segment under consideration. Some of them, however depend on the values of moments and/or displacements at mid or quarter points along the segment. It is not always possible to have stations positioned exactly at the mid or quarter points required because even though stations are positioned at mid and quarter points between adjacent flange restraints, segments do not always extend between adjacent flange restraints (particularly when the critical flange changes due to moment reversal). In such cases, SPACE GASS simply takes the moment and/or displacement values from the station nearest to the required point. For the AS4100 and NZS3404 modules, m is calculated using the formula in clause 5.6.1.1(a)(iii) when the segment is restrained at both ends. If the segment is unrestrained at one end, AS4100 and NZS3404 require the bending moment diagram to be matched to one of the three diagrams shown in table 5.6.2. This is very difficult when the bending moment diagram could be any conceivable shape. Therefore, SPACE GASS uses m = 0.25 if there is a non-zero moment at the unrestrained end, m = 2.25 if the mid-segment moment is less than 25% of the restrained end moment, m = 1.25 if the midsegment moment is less than 50% of the restrained end moment or otherwise m = 1.0. This is less conservative than the approach adopted in v12.25.334 and earlier versions.

589


Eccentric effects for compression members Eccentric end connection effects for angles, channels and Tee sections subjected to axial compression are normally taken into account by calculating the extra eccentric moments and then adding them to the normal design moments along the entire length of the design group (unless they cause a net reduction in the final design moment). For all codes, the eccentric moments are calculated by multiplying the axial force by the distance from the centroid of the connected plate to the centroid of the cross section.

Eccentric effects for compression members can be suppressed if required.

590

Steel Member Design

Eccentric effects for tension members Eccentric end connection effects for angles, channels and Tee sections subjected to axial tension are taken into account in various ways depending on the design code being used. For AS1250, SABS0162 and AS3990, SPACE GASS simply calculates the extra eccentric moments and then adds them to the normal design moments along the entire length of the design group provided that they don’t cause a net reduction in the final design moment. This method is used instead of reducing the effective area of the cross section in accordance with AS1250 clause 7.3.2, SABS0162 clause 9.2 or AS3990 clause 7.3.2. The AS4100 and NZS3404 modules also use the above method of calculating and adding eccentric moments if the Kt method is not used. Alternatively, if the Kt method is used then Kt is calculated in accordance with AS4100/NZS3404 clause 7.3.2 and used to reduce the member tensile capacity rather than eccentric moments being added. The Kt method also applies to I, H or channel sections which are connected by their flanges only. For these sections, SPACE GASS assumes that the provisions of AS4100/NZS3404 clauses 7.3.2(b)(i) and (ii) have been met and uses Kt = 0.85.

Eccentric effects for tension members can be suppressed if required.

591


The code check When all of the member properties, effective lengths, design loads and other factors have been calculated, they are fed into the appropriate code specific subroutines to determine the success or failure of the code check. During this process the subroutines also calculate the load factor or the combined stress ratio which is then passed back to SPACE GASS along with many other design result parameters. If the latest check is more critical than any previous checks for the design group then the results of the latest check are retained as the governing case until another check further along the design group yields a smaller load factor or a larger combined stress ratio. After considering every segment in the design group for each design load case, SPACE GASS saves the data for the governing section and member check cases and moves on to the next design group.

592

Steel Member Design

Steel member design results At the end of a steel member design or check, you can produce a full report showing the results of the design or check. The pass/fail status of each member can also be shown graphically in a color-coded display as described in "View steel member design results". Filters can also be created to filter members in accordance with their pass/fail status as described in "Filters". You can also query individual members graphically to get an abbreviated report showing the results of the design or check as described in "Query steel member design results".

Reports for single angle sections are in principal axes for AS4100, BS5950, NZS3404, AS4600, AISC-LRFD, AISC-ASD and IS800. Updating analysis member sizes If you have performed a design (as opposed to a check), the final design member sizes are probably slightly different to those in the analysis section property data. So that the design is based on the same member sizes as the analysis, the new design member sizes should be transferred back into the analysis and then the analysis and design process iterated until the analysis and design sizes are the same. This is described in detail in "Updating member sizes". Member, section and shear checks For each steel design member in a full report, three lines of information relating to section, member and shear checks are presented. These represent summaries of the results of the three main checks that are performed when a steel member is designed or checked. The section and shear checks are performed at numerous points along each design group. They consider the capacity of a cross section and are not related to effective lengths or any other conditions which occur away from the cross section under consideration. The forces and moments used in a section or shear check are the ones which occur simultaneously at the cross section. The governing location for the section and shear checks is shown under the "Start Pos’n" heading. The member check is performed for each segment between adjacent points of critical flange restraint. The member check is affected by the axial and bending effective lengths of the segment and the shape of the deflection and bending moment diagrams along the segment. The forces and moments used in a member check are the maximum values taken from anywhere along the segment. The governing segment for the member check has its start and finish locations shown under the "Start Pos’n" and "Finish Pos’n" headings. Load factor The load factor applies only to AISC-LRFD, EUROCODE 3, AS4100, AS4600, BS5950, NZS3404, HK CP2011 and IS800. It is the amount by which the design actions can be increased before the point of failure is reached. For example, if the steel design returns a load factor of 1.12, you could theoretically increase your loads by 12%, repeat the analysis and design, and expect the load factor to reduce to 1.00. This is not always the case however, because the non-linearity of the analysis means that increasing your loads by 12% does not guarantee that the design actions will also increase by exactly 12%.

593

SPACE GASS 12 User Manual For members designed in accordance with these codes, the load factor must be greater than 1.0. This means that the design actions can be factored up by an amount greater than 1.0 before the member becomes inadequate.

Because the relationship between design actions and design capacity is not linear, the load factor is not equal to the inverse of the (design actions)/(design capacity) failure equation at the end of the detailed calculations for each member in the steel design report. Zero variables in reports You may notice that some variables in the steel member design output report are shown as zero when it appears that they should have a non-zero value. This occurs because the steel member design modules only calculate the values that are applicable to the design actions and section type. Variables which are not applicable for the governing failure mode are not calculated and hence appear as zero in the output report. Weighted average load factors (WALF) A weighted average load factor (WALF) gives an overall indication of the efficiency of the design for each load case. The WALF for a given load case is calculated by summing the load factors and masses for each member according to (LF x Mass) / (Mass), where LF is the load factor for each steel member and Mass is its mass. The WALF should be greater than 1.0, and the closer to 1.0 the more efficient the design. A WALF significantly greater than 1.0 could indicate that many of the steel members are not working to their full capacity.

594

Steel Member Design

Steel member design/check assumptions This section lists the main assumptions that are made in the steel member design module. Some of these assumptions are also described in the previous sections of this chapter and others are listed only in this section. It is up to you to check that these assumptions are suitable for your situation. Note that some of the following general assumptions may be overridden by the code specific items listed in the sections immediately following this one. 1. Frame imperfections are not automatically allowed for during the design phase. When applicable (usually for multi-storey frames), you should apply notional horizontal forces or initial deformations to the analysis model in accordance with the requirements of the design code. 2. The top flange of a member is the flange on the positive local y-axis (or z-axis if the section has been flipped) side of the member. The top flange of a member can be easily determined by displaying the member local axes graphically and observing the direction of the local y-axis (or z-axis if flipped). 3. The top flange of a group as a whole is defined such that it is the same as the top flange of the first member in the group. 4. The critical flange at any point within a segment is assumed to be the compression flange unless either end of the segment is laterally unrestrained in which case it is assumed to be the tension flange. SPACE GASS is not able to determine whether a loading condition is predominantly due to gravity or wind and you should therefore check that the above rule is valid for your situation. 5. All section and member capacities are calculated assuming that stiffeners do not exist. 6. The AS4100, AISC-LRFD, BS5950, EUROCODE 3, HK CP2011 and NZS3404 modules assume that second order effects have been taken into account by a second order elastic analysis. Moment magnification is not considered. 7. The AS4100, AISC-LRFD, BS5950, EUROCODE 3, HK CP2011 and NZS3404 modules assume that the design load cases are factored (ultimate). 8. For single angle sections, the effective lengths and flange restraints must be input relative to the non-principal axes. For all other sections, they must be input relative to the principal axes. 9. The compression effective lengths Lmx and Lmy, used by AS4100 and NZS3404 in clause 8.4.2.2 for the calculation of Nc when ke=1.0, are assumed to be equal to the lesser of the total design group length and the normal compression effective lengths for the segment under consideration. Lmx = MIN(Ltot,Lcmajor) and Lmy = MIN(Ltot,Lcminor), where Ltot is the total design group length and Lcmajor and Lcminor are the normal compression effective lengths. 10. The torsion effective length used by AS4100 and NZS3404 is assumed to be equal to the distance between adjacent full or partial restraints. 11. A C (continuous) flange restraint is assumed to be equivalent to a series of L (lateral) flange restraints spaced at increments of 1mm for the length of the continuous

595

SPACE GASS 12 User Manual restraint. 12. If C (continuous) or I (ignore) flange restraints are repeated without R, S, F, P or L restraints inbetween (eg. CCC, III or CI) then the last C or I restraint is used and the previous repeated ones are discarded. 13. If an intermediate flange restraint is positioned at the beginning or end of a design group then it is ignored in favour of the appropriate end flange restraint. 14. Member offsets are automatically ignored (skipped over) during a steel member design/check provided that they occur at the ends of a design group. They are treated the same as I (ignore) flange restraints. 15. The extra restraint condition in AS1250, SABS0162, BS5950, HK CP2011 and AS3990 that provides partial restraint against lateral rotation (about the cross section minor axis) of the critical flange is not supported. 16. Because it is difficult for SPACE GASS to determine whether a member is a true cantilever or not, AS1250 clause 5.9.4, SABS0162 clause 7.2.3(b), BS5950 clause 4.3.5.4/4.3.5.5, HK CP2011 clause 8.3.4.3 and AS3990 clause 5.9.4 have not been considered. This may cause the bending effective length for cantilevers to be underestimated and you should therefore check the bending effective length for cantilevers calculated by the AS1250, SABS0162, BS5950, HK CP2011 and AS3990 modules. 17. When calculating kt for AS4100 or NZS3404, if the critical flange switches from top to bottom within the segment, the critical flange thickness is assumed to be the thickness of the flange at the end of the segment. 18. When calculating kl, SPACE GASS assumes conservatively that top flange loads always occur within the segment rather than at the segment end(s). 19. kl is calculated for "downwards" loads regardless of the member orientation and flange positions. A "downwards" load is assumed to act in the direction from the top flange to the bottom flange. If you want kl=1.0 for columns, sloping beams or beams on their side then you should set the load height position to "Shear centre" regardless of the loaded flange or the load direction. 20. The direction of the transverse load acting on a segment is determined by the sign of the difference in shear force between the two segment ends. 21. AS1250, SABS0162, BS5950, HK CP2011 and AS3990 do not give specific rules for calculating kr for all combinations of flange restraints at the ends of the segment. In such cases interpolation has been used to calculate some of the values of kr. 22. Eccentric end connection effects (if not suppressed) are taken into account in different ways depending on the design code being used. In most cases, the eccentric end moments are simply added to the normal design moments for the entire design group. Exceptions are BS5950 which optionally uses the provisions of clauses 4.6.3 (tension) or 4.7.10 (compression) and AS4100 and NZS3404 which use a Kt factor for tension members (if activated). 23. Where applicable (see previous item), moments due to eccentric end connection effects for angles, channels and Tee sections subjected to axial loads are added to the normal design moments only if they don’t cause a net reduction in the final design 596

Steel Member Design moment. 24. Eccentric end moments are calculated by multiplying the axial force by the distance from the centroid of the connected plate to the centroid of the cross section. 25. The major axis of a single or double angle section is assumed to be parallel to the short leg(s) of the section. 26. Double angle sections are assumed to have no space between the individual angle sections. 27. The AS1250, SABS0162 and AS3990 modules assume that double angles are connected together at intermediate points sufficient to ensure that half of the design axial compressive force for the combined section does not exceed the compressive capacity of each angle section considered individually using an effective length (for buckling of the sections away from each other) equal to the distance between connection points. 28. The AS1250, SABS0162 and AS3990 modules consider only axial forces and shears for single or double angle sections. Bending moments are not considered. Eccentric end moments are considered where applicable. The AS4100, BS5950, HK CP2011, EUROCODE 3 and NZS3404 modules consider axial forces, shears (along minor axis) and bending moments (about both axes) for single or double angle sections. 29. The AS4100, NZS3404, AISC-ASD, AISC-LRFD, EUROCODE 3, BS5950 and HK CP2011 modules convert double angle sections into the equivalent Tee section and then treat them as a solid Tee shape. The AS4100, NZS3404 and HK CP2011 modules do not support double starred angles. 30. Beam Tees have the major axis parallel to the flange and are therefore assumed to have their web vertical (assuming a zero direction angle and no flipping). 31. Column Tees have the major axis parallel to the web and are assumed to be lying on their side with their flange vertical (assuming a zero direction angle and no flipping). 32. The AS1250, SABS0162 and AS3990 modules do not support column Tee sections. 33. The AS4100 and NZS3404 modules do not support welded Tee sections unless they are beam Tees with d/t<15 (lightly welded longitudinally) or d/t<14 (heavily welded longitudinally). 34. The AS4100 and NZS3404 modules assume that heavily welded (longitudinally) I and H sections with equal flanges are flame cut. Lightly welded (longitudinally) or unequal flanged I and H sections and all plate web girders are assumed to be welded "as rolled". 35. The AS1250, SABS0162 and AS3990 modules do not support welded box sections. 36. The AS4100 and NZS3404 modules do not support welded circular hollow sections, channels or angles. 37. The AS4100, BS5950, HK CP2011 and NZS3404 modules assume that channel sections have equal flanges.

597

SPACE GASS 12 User Manual 38. The AS4100, BS5950, HK CP2011 and NZS3404 modules assume that angle sections have uniform plate thicknesses throughout the section. 39. The AS4100 and NZS3404 modules do not support solid sections. 40. The BS5950 and HK CP2011 modules assume that solid sections are class 1. 41. When calculating the area removed from the section due to a bolted end connection, SPACE GASS assumes that the bolts are through the web(s) unless the end connection type is specified as "F", in which case the bolts are assumed to be through the flange(s). 42. The area removed from the section due to a bolted end connection is assumed to apply for a distance of 250mm from each end of the design group. 43. The BS5950 module assumes conservatively that single angle sections are connected with a single fastener for clause 4.7.10. 44. The AS4100 and NZS3404 modules perform a web capacity check in accordance with appendix I. If the check fails, SPACE GASS treats it as a warning rather than a failure condition. 45. Serviceability requirements are not considered automatically. They must be checked manually by direct inspection of displacement diagrams. 46. Torsional effects are not considered. 47. Member end bearing capacity is not considered. 48. For the AS4100 and NZS3404 modules, m is calculated using the formula in clause 5.6.1.1(a)(iii) when the segment is restrained at both ends. If the segment is unrestrained at one end, AS4100 and NZS3404 require the bending moment diagram to be matched to one of the three diagrams shown in table 5.6.2. This is very difficult when the bending moment diagram could be any conceivable shape. Therefore, SPACE GASS uses m = 0.25 if there is a non-zero moment at the unrestrained end, m = 2.25 if the mid-segment moment is less than 25% of the restrained end moment, m = 1.25 if the mid-segment moment is less than 50% of the restrained end moment or otherwise m = 1.0. This is less conservative than the approach adopted in v12.25.334 and earlier versions.. 49. The AS4100, BS5950 and NZS3404 modules do not consider shear force in the major axis direction. 50. If any term in the steel member design failure equation becomes negative, it is assumed that the section has failed and a value of 9.99 is used in place of the negative value. 51. The brace, purlin, girt or other member that provides full, partial or lateral restraint to the critical flange of a member must be capable of resisting the force required to provide such restraint. This is not automatically allowed for in the analysis or design. If you wish to take this into account then you should add the restraint forces to your applied loads. The restraint forces are code specific and you should refer to the appropriate clauses for the design code you are using.

598

Steel Member Design This effect is particularly important for deep beams where the forces required to restrain the critical flange can be quite high. You should check that your model is capable of withstanding these forces.

599


BS5950-1:2000 code specific items Sections considered Incorporates Corrigendum No 1 3 Properties of materials and section properties 3.1 Structural steel 3.1.1 Design Strength 3.1.3 Other properties 3.4 Section properties 3.4.1 Gross cross-section 3.4.2 Net Area 3.4.3 Effective net area 3.4.4 Deductions for bolt holes 3.5 Classification of cross sections 3.5.1 General 3.5.2 Classification 3.5.5 Stress ratios for classification 3.5.6 Effective plastic modulus 3.5.6.1 General 3.5.6.2 I or H sections with equal flanges 3.5.6.3 Rectangular Hollow Sections 3.5.6.4 Circular Hollow Sections 3.6 Slender cross-sections 3.6.1 Effective section properties 3.6.2 Doubly symmetric cross-sections 3.6.2.1 General 3.6.2.2 Effective area 3.6.2.3 Effective modulus when web is fully effective 3.6.2.4 Effective modulus when web is slender 3.6.3 Singly symmetric and unsymmetrical cross-sections 3.6.6 Circular hollow sections 4 Design of structural members 4.1 General 4.1.1 Application 4.1.2 Class of cross section 4.2 Members subject to bending 4.2.1 General 4.2.1.1 General conditions a, c, d, e 4.2.3 Shear Capacity 4.2.5 Moment Capacity 4.2.5.1 General 4.2.5.2 Low Shear 4.2.5.3 High Shear 4.2.5.5 Bolt holes 4.3 Lateral-torsional buckling 4.3.1 General 4.3.4 Destabilizing load 4.3.6 Resistance to lateral-torsional buckling 4.3.6.1 General 4.3.6.2 I, H, channel and Box sections with equal flanges 4.3.6.3 I-sections and box sections with unequal flanges 600

Steel Member Design 4.3.6.4 Buckling resistance moment b,c 4.3.6.5 Bending strength pb 4.3.6.6 Equivalent uniform moment factor mLT 4.3.6.7 Equivalent slenderness LT 4.3.6.8 Buckling parameter and torsional index 4.3.6.9 Ratio W 4.3.8 Buckling resistance moment for single angles 4.3.8.1 General 4.3.8.2 Basic method 4.4 Plate Girders 4.4.1 General 4.4.2 Design Strength 4.4.3 Dimensions of webs and flanges 4.4.3.1 General 4.4.3.2 Minimum web thickness for serviceability a 4.4.3.3 Minimum web thickness to avoid compression flange buckling a 4.4.4 Moment Capacity 4.4.4.1 Web not susceptible to shear buckling 4.4.4.2 Web susceptible to shear buckling 4.4.5 Shear buckling resistance 4.4.5.1 General 4.4.5.2 Simplified method 4.6 Tension members 4.6.1 Tension capacity 4.6.2 Members with eccentric connections 4.6.3 Simple tension members 4.6.3.1 Single angle, channel or T-section members 4.7 Compression members 4.7.2 Slenderness 4.7.4 Compression resistance 4.7.5 Compressive strength 4.7.6 Eccentric connections c 4.7.10 Angle, channel or T-section struts 4.7.10.1 General 4.7.10.2 Single angles a (welded connection) c 4.7.10.4 Single channels b 4.7.10.5 Single T-sections b 4.8 Members with combined moment and axial force 4.8.1 General 4.8.2 Tension members with moments 4.8.2.1 General 4.8.2.2 Simplified method 4.8.2.3 More exact method 4.8.3 Compression members with moments 4.8.3.1 General 4.8.3.2 Cross section capacity 601

SPACE GASS 12 User Manual 4.8.3.3 Member buckling resistance 4.8.3.3.1 Simplified method 4.8.3.3.2 More exact method for I or H sections with equal flanges 4.8.3.3.3 More exact method for CHS, RHS, or box sections with equal flanges 4.8.3.3.4 Equivalent uniform moment factors 4.9 Members with biaxial moments 6 Connections 6.2 Connections using bolts 6.2.3 Effect of bolt holes on the shear capacity B Lateral-torsional buckling of members subject to bending B.1 Basic case B.2 Buckling resistance B.2.1 Bending strength B.2.2 Perry factor and Robertson constant B.2.3 Uniform I,H and channel sections with equal flanges B.2.4 Uniform I and H sections with unequal flanges B.2.4.1 Equivalent slenderness B.2.4.2 Double curvature bending B.2.6 Box sections (including RHS) B.2.6.1 Equivalent slenderness B.2.6.2 Torsion constant for a box section B.2.6.3 Torsion constant for an RHS B.2.7 Plates and flats B.2.8 T-sections B.2.8.1 Axes B.2.8.2 Equivalent slenderness B.2.8.3 Warping constant B.2.9 Angle sections B.2.9.1 Axes B.2.9.2 Equal angles B.2.9.3 Unequal angles C Compressive strength C.1 Strut formula C.2 Perry factor and Robertson constant H Web buckling resistance H.1 Shear buckling strength H.3 Resistance of a web to combined effects H.3.1 General H.3.2 Reduction factor for shear buckling H.3.3 Sections other than RHS H.3.3.1 Combined shear, moment and axial compression H.3.3.2 Combined shear, moment and axial tension H.3.4 RHS sections H.3.4.1 Combined shear, moment and axial compression H.3.4.2 Combined shear, moment and axial tension I Combined axial compression and bending I.1 Stocky members I.2 Reduced plastic moment capacity 602

Steel Member Design I.2.1 I or H section with equal flanges I.4 Single angle members I.4.1 General I.4.2 Basic method Assumptions 3.1.1 Design strength py obtained from fy in SPACE GASS library. A warning, not a failure is given if py exceeds Us/1.2. py is not adjusted. 3.4.3 The determination of steel grade for calculating the Ke value is based on the SPACE GASS library fy value, falling between the ranges specified in Table 9. 3.4.4 The bolt hole area is based on the values specified in the SPACE GASS Steel Member Design data. 3.5 Solid square and solid circle sections are assumed to be a Class 1. Solid rectangle is assumed to be an I beam with no flange outstands. I and Box shapes use the "Generally" limits in Tables 11 and 12. 3.5.5 Unequal flanges for box sections use r1 eq 3.5.5b divided by 2.0 to allow for the 2 webs. Outstands of box girders are not taken into account for the calculation of r1. 3.6.2.4 When used for webs for channels, webs are assumed to be 40t instead of 120t in accordance with Table 11 and the use of 3.6.3. 4.2.3 Only vertical projection of inclined box girder web considered in shear capacity. 4.2.5.1 A warning, not a failure is given if the 1.2pyZ limit is reached. 4.2.5.2 Alternative for Class 3 sections used. 4.2.5.3 Alternative for Class 3 sections used. Alternative with regards to reference H.3 for Class 3 and 4 sections not considered. 4.2.5.5 Bolt holes assumed to be distributed equally between top and bottom flange for flanges and for webs equally distributed between the tension and compression zone in bending. 4.3.6.7b Channels are loaded through their shear centre. 4.4.4.2c When using H3 and the section has two webs, the web forces are equally shared between the webs - class 4 flanges - only the effective parts of the flanges are used for calculation of flange capacity. 4.4.5 Simplified method used with stiffener spacing equal to infinity. 4.4.5.2 When using H1 to determine qw, sections other than I beams are assumed to be applied in the same way where there are two webs (boxes), the web capacity is for each web. 4.6 Full section properties used except where explicitly specified Zxeff and Sxeff. 4.6.2 If no eccentric moments are added and the section's connected elements cause eccentricity then 4.6.3 used. 4.7.2 The 20% increase in slenderness for alternating restraints has not been allowed for. 4.7.5 Reduced py is used for all welded sections. Table 23 welded angles, channels and Tees are assumed to be rolled but py is reduced as per 4.7.5. Notes 2 and 3 not allowed for. 4.7.6c If no eccentric moments are added and the section's connected elements cause eccentricity then 4.7.10 used. 4.7.10.1 The 20% increase in slenderness for alternating restraints has not been allowed for. 4.7.10.2 If there is a bolt area in one flange only then a single bolt hole is assumed, 80% reduction allowed for. 4.7.10.4 If there is a bolt hole in the web then a single row is assumed. 4.7.10.5 If there is a bolt hole in the flange then a single row is assumed. 4.8.2.3 Only equal flanged I shapes, box shapes and CHS class 1 or 2 use this clause. Other sections use 4.8.2.2. 4.8.2.2 App I.3 not used for asymmetric sections. 603

SPACE GASS 12 User Manual 4.8.3.2 App I.3 not used for asymmetric sections. 4.8.3.3 App I.1 is used for stocky members. 4.8.3.3.4 mLT is based on the segment length, mx is based on the Group length, my is based on the segment length, myx is based on the group length B.2.4 Channels with unequal flanges treated the same as unequal I beams refer 4.3.6.7b. B.2.9.2 Star angles treated same as single angle but combined properties used. H.3.1 Strut action and moment amplification not allowed for.

604

Steel Member Design

Hong Kong CP2011 code specific items Sections considered 3 Materials 3.1 Structural Steel 3.1.2 Design strength for normal strength steels 3.1.6 Other properties 6 Design Methods and Analysis 6.8 Second-Order P- Elastic Analysis 6.8.2 Method of Analysis items (1) and (2) only 6.8.3 Applications and Limitations 7 Section Classification 7.1 General 7.2 Classification 7.3 Stress Ratios for Classification 7.5 Effective Plastic Modulus 7.5.1 General 7.5.2 I or H Sections with equal flanges 7.5.3 Rectangular hollow sections 7.5.4 Circular hollow sections 7.6 Effective Width method for slender cross sections 7.8 Shift of the centroid of the effective cross section 8 Design of Structural Members 8.1 General 8.2 Restrained Beams 8.2.1 Shear capacity 8.2.2 Moment capacity 8.2.2.1 Low Shear condition 8.2.2.2 High Shear condition 8.3 Lateral-Torsional buckling of Beams 8.3.3 Normal and destabilising loads 8.3.5 Moment resistance to Lateral-torsional buckling 8.3.5.1 Limiting slenderness 8.3.5.2 Buckling resistance moment 8.3.5.3 Equivalent dlenderness for flexural-torsional buckling 8.4 Plate Girders 8.4.1 Design strength 8.4.2 Minimum web thickness for servicability 8.4.3a Minimum web thickness to avoid compression flange buckling 8.4.4 Moment Capacity of restrained girders 8.4.4.1 Web suspectible to shear buckling 8.4.4.2 Web susceptible to shear buckling 8.4.5 Effects of Axial force 8.4.6 Shear buckling resistance 8.5 Buckling resistance moment for a single angle member 8.6 Tension members 8.6.1 Tension Capacity 8.6.2 Members with eccentric connections 8.6.3 Single and double angle, channel and T sections 8.7 Compression Members

605

SPACE GASS 12 User Manual 8.7.4 Slenderness 8.7.5 Compression resistance 8.7.6 Compressive strength 8.7.7 Eccentric connections 8.8 Tension members under combined axial force and moments 8.9 Compression Members under combined axial force and moments 8.9.1 Cross section capacity 8.9.2 Member buckling resistance 9 Connections 9.3.4.4 Effective area for tension 9.3.4.5 Effective area for shear Appendix 8.1 Appendix 8.2 Appendix 8.3 Assumptions 3.1.2 Class 1 and 1H steels assumed. 6.8.2(3) Frame and member imperfections are not automatically considered in the analysis, however if clause 8.9.2 is used instead of clause 6.8.3 then there is no requirement for member imperfections in the analysis. 1. Mcx and Mcy = Zpy. 7.5.1 I or H sections with unequal flanges Seff = Z as per other sections. 7.6 Same method as BS5950-2000 is adopted to calculate effective section and change in centroid and properties for slender sections but with HK element limits. 8.2 Beam checked whether fully restrained or not. 8.3.5.2 Mb = Mcx from 8.2.2 if Lateral Torsional Buckling need not be checked. 8.3.5.3 Box sections use this code section. 8.3.5.3 Channels assume that loads pass through shear centre - warning given. 8.4 Webs without intermediate or transverse stiffeners assumed (a = infinity). 8.4.2 Warning given if eq 8.30 not met. 8.4.3 Warning given if eq 8.33 not met. 8.7 No check is done for compressive resistance if clause 6.8.3 is used instead of clause 8.9.2. 8.8 Only eq 8.77 is applied. 8.9.2 If clause 8.9.2 is used instead of clause 6.8.3 then second-order moments are used in equation 8.79, making it slightly conservative. MLT is max moment in segment, Mx is max moment in group and My is max moment in segment.

606

Steel Member Design

AISC 360-10 code specific items Sections considered B. DESIGN REQUIREMENTS B3. Design Basis 1. Required Strength 2. Limit States 3. Design for Strength Using Load and Resistance Factor Design (LRFD) 4. Design for Strength Using Allowable Strength Design (ASD) 5. Design for Stability B4. Member Properties 1. Classification of Sections for Local Buckling 1a. Unstiffened Elements 1b. Stiffened Elements 2. Design Wall Thickness for HSS 3. Gross and Net Area Determination 3a. Gross Area 3b. Net Area D. DESIGN OF MEMBERS FOR TENSION D2. Tensile Strength D3. Effective Net Area E. DESIGN OF MEMBERS FOR COMPRESSION E1. General Provisions E2. Effective Length E3. Flexural Buckling of Members without Slender Elements E4. Torsional and Flexural-Torsional Buckling of Members Without Slender Elements E5. Single Angle Compression Members E7. Members with Slender Elements 1. Slender Unstiffened Elements, Qs 2. Slender Stiffened Elements, Qa F. DESIGN OF MEMBERS FOR FLEXURE F1. General Provisions F2. Doubly Symmetric Compact I-Shaped Members and Channels Bent About Their Major Axis 1. Yielding 2. Lateral-Torsional Buckling F3. Doubly Symmetric I-Shaped Members With Compact Webs and Noncompact or Slender Flanges Bent About Their Major Axis 1. Lateral-Torsional Buckling 2. Compression Flange Local Buckling F4. Other I-Shaped Members With Compact or Noncompact Webs Bent About Their Major Axis 1. Compression Flange Yielding 2. Lateral-Torsional Buckling 3. Compression Flange Local Buckling 4. Tension Flange Yielding F5. Doubly Symmetric and Singly Symmetric I-Shaped Members With Slender Webs Bent About Their Major Axis 1. Compression Flange Yielding 2. Lateral-Torsional Buckling 3. Compression Flange Local Buckling 4. Tension Flange Yielding F6. I-Shaped Members and Channels Bent About Their Minor Axis 1. Yielding 607

SPACE GASS 12 User Manual 2. Flange Local Buckling F7. Square and Rectangular HSS and Box-Shaped Members 1. Yielding 2. Flange Local Buckling 3. Web Local Buckling F8. Round HSS 1. Yielding 2. Local Buckling F9. Tees and Double Angles Loaded in the Plane of Symmetry 1. Yielding 2. Lateral-Torsional Buckling 3. Flange Local Buckling of Tees 4. Local Buckling of Tee Stems in Flexural Compression F10. Single Angles 1. Yielding 2. Lateral-Torsional Buckling 3. Leg Local Buckling F11. Rectangular Bars and Rounds 1. Yielding 2. Lateral-Torsional Buckling F12. Unsymmetrical Shapes 1. Yielding 2. Lateral-Torsional Buckling 3. Local Buckling F13. Proportions of Beams and Girders 1. Strength Reductions for Members With Holes in the Tension Flange 2. Proportioning Limits for I-Shaped Members G. DESIGN OF MEMBERS FOR SHEAR G1. General Provisions G2. Members With Unstiffened or Stiffened Webs 1. Shear Strength 2. Transverse Stiffeners G3. Tension Field Action 1. Limits on the Use of Tension Field Action 2. Shear Strength With Tension Field Action 3. Transverse Stiffeners G4. Single Angles G5. Rectangular HSS and Box-Shaped Members G6. Round HSS G7. Weak Axis Shear in Doubly Symmetric and Singly Symmetric Shapes H. DESIGN OF MEMBERS FOR COMBINED FORCES AND TORSION H1. Doubly and Singly Symmetric Members Subject to Flexure and Axial Force 1. Doubly and Singly Symmetric Members Subject to Flexure and Compression 2. Doubly and Singly Symmetric Members Subject to Flexure and Tension 3. Doubly Symmetric Rolled Compact Members Subject to Single Axis Flexure and Compression H2. Unsymmetric and Other Members Subject to Flexure and Axial Force H3. Members Subject to Torsion and Combined Torsion, Flexure, Shear and/or Axial force 1. Round and Rectangular HSS Subject to Torsion 2. HSS Subject to Combined Torsion, Shear, Flexure and Axial Force 3. Non-HSS Members Subject to Torsion and Combined Stress H4. Rupture of Flanges With Holes Subject to Tension Limit state equations used D. DESIGN OF MEMBERS FOR TENSION 608

Steel Member Design D2-1 Pg 16.1-26 - section,member D2-2 Pg 16.1-26 - section,member E. DESIGN OF MEMBERS FOR COMPRESSION E3-1 Pg 16.1-33 - member E4-1 Pg 16.1-34 - member E7-1 Pg 16.1-40 - member F, DESIGN OF MEMBERS FOR FLEXURE F2-1 Pg 16.1-47 - section, member F2-2 Pg 16.1-47 - member F2-3 Pg 16.1-47 - member F3-1 Pg 16.1-49 - section, member F3-2 Pg 16.1-49 - section, member F4-1 Pg 16.1-50 - section, member F4-2 Pg 16.1-50 - member F4-3 Pg 16.1-50 - member F4-13 Pg 16.1-52 - section, member F4-14 Pg 16.1-52 - section, member F4-15 Pg 16.1-53 - section, member F5-1 Pg 16.1-54 - section, member F5-2 Pg 16.1-54 - member F5-7 Pg 16.1-55 - section, member F5-10 Pg 16.1-55 - section, member F6-1 Pg 16.1-55 - section, member F6-2 Pg 16.1-56 - section, member F6-4 Pg 16.1-56 - section, member F7-1 Pg 16.1-56 - section, member F7-2 Pg 16.1-57 - section, member F7-3 Pg 16.1-57 - section, member F7-5 Pg 16.1-57 - section, member F8-1 Pg 16.1-57 - section, member F8-2 Pg 16.1-57 - section, member F8-3 Pg 16.1-57 - section, member F9-1 Pg 16.1-58 - section, member F9-4 Pg 16.1-58 - member F9-6 Pg 16.1-59 - section, member F9-7 Pg 16.1-59 - section, member F9-8 Pg 16.1-59 - section, member F10-1 Pg 16.1-60 - section, member F10-2 Pg 16.1-60 - member F10-3 Pg 16.1-61 - member F10-7 Pg 16.1-62 - section, member F10-8 Pg 16.1-62 - section, member F11-1 Pg 16.1-63 - section, member F11-2 Pg 16.1-63 - member F11-3 Pg 16.1-63 - member F12-1 Pg 16.1-63 - section, member F13-1 Pg 16.1-64 - section, member G. DESIGN OF MEMBERS FOR SHEAR G2-1 Pg 16.1-67 - section, member, shear G6-1 Pg 16.1-72 - section, member, shear H. DESIGN OF MEMBERS FOR COMBINED FORCES AND TORSION H1-1a Pg 16.1-73 - member H1-1b Pg 16.1-73 - member H1-2 Pg 16.1-75 - member H2-1 Pg 16.1-76 - section, member 609

SPACE GASS 12 User Manual H3-1 H3-6 H3-8 H4-1

Pg 16.1-77 - section, member Pg 16.1-78 - section, member Pg 16.1-79 - section, member Pg 16.1-79 - section

Assumptions GENERAL The root radius for square and rectangular tubes is taken as the inside radius. Flange bolt holes equally divided between flanges. Web bolt holes equally divided between webs where applicable. If the design calculates a high Ultimate Load Factor then a default failure equation (Yield about xx axis) will be returned. Warning - If a value has exceeded a limit related to a warning, the value is NOT adjusted to be within that limit, its actual value is used in the calculation. Section B4.2 Design Wall Thickness for HSS This issue comes about due to the practice of some steel manufacturers producing HSS sections with a wall thickness at the very low end of what the specifications allow. To account for this, the US section libraries supplied with SPACE GASS 12.27 and later include adjustments to the HSS section properties (depending on the type of HSS section) and no extra adjustments are made to their properties during an AISC 360-10 design or check. In SPACE GASS 12.26 and earlier, the US section libraries contained non-adjusted properties for HSS sections and so to allow for this their wall thickness was multiplied by 0.93 during an AISC 360-10 design or check. It is therefore important that you match the version of the US library with the same version of SPACE GASS, otherwise unsafe designs of HSS sections could result. It is also important that you don't use HSS sections from SPACE GASS 12.26 and earlier with other non-US design codes. Section B4.3b. Net Area 1/16" or 2 mm allowance for hole diameter already assumed to be allowed for in the design data input. No allowance for chain holes made. Chapter D Design of Members for Tension Pin connected members not checked. Block shear strength not checked. Eyebars not checked. Section D3. Effective Net Area A number of factors are unknown ie the length of the connection, number of bolts in line and the type of the weld used. The user has the choice to leave U as 1.0 via the U flag or turn it on and use the conservative approach as detailed in the Commentary Page 16.1-250 where the net area of the connected elements are used as Ae. A U value is returned to indicate the reduction from the net area ie U = Ae/An. Circular, square or rectangular solid sections plus circular tubes use a worst case assumption of U = 0.75. Section E5 Single Angle Compression members Section E5.(a) used - group length used as they are individual members or web members. Section F Outstands on box girders treated as tee flanges. Non double symmetric box girders are not supported by F7, each flange and web is still checked individually. No allowance made for loads placed above or below the centroid. No allowance for cantilevers in calculation of Cb. Section F10. Single Angles Bending about principal axis only. Section F11.1

610

Steel Member Design Yielding of solid bars, warning issued if slenderness limit exceeded, capacities still calculated. Section F13.2 Proportions limits for I shaped members Warning given if limits exceeded, calculations still done even though limits have been exceeded. Section G No reduction in shear areas for bolt holes. No web transverse stiffeners assumed. No shear tension field action is considered (Sect G3). Solid circle shear done same as CHS with wall thickness equal to radius. Section G4 Single Angles Star shapes have double shear capacity of equivalent single angle. Section G5 Rectangular HSS and Box shaped members Box sections with different thickness flanges and possibly outstands, the element that produces the worst Cv value is used as the controlling cv and the sum of all of the contributing shear elements is used for Aw. If there is a flange outstand on the box girder these are treated like a T stem kv = 1.2. Section G7 weak axis shear If any torsion then equation H3-8 used. Section H1.3 Applied if section is rolled compact in flexure about major axis (axial class ignored).

611


Eurocode EN 1993-1-1:2005 code specific items Sections considered 1. General 1.1.2(1) Scope of Part 1.1 of Eurocode 3 1.7 Conventions for member axes 3. Materials 3.2.2(1) Ductility requirements fu/fy 3.2.6(1) Design values of material coefficients 5. Structural analysis 5.5 Classification of cross sections 5.5.1 Basis 5.5.2 Classification (1),(2),(3),(4),(5),(6),(7),(8),(10) 6. Ultimate limit states 6.1 General (1),(3),(4) 6.2.2 Section properties 6.2.2.1 Gross cross-section 6.2.2.2 Net area (1),(2),(3) 6.2.2.5 Effective cross-section properties for Class 4 cross-sections (1),(2),(3),(4) 6.2.3 Tension (1),(2),(3),(5) 6.2.4 Compression (1),(2),(3),(4) 6.2.5 Bending moment (1),(2),(3),(4),(5),(6) 6.2.6 Shear (1),(2),(3),(4),(5),(6),(7) 6.2.8 Bending and shear (1),(2),(3),(5) 6.2.9 Bending and axial force 6.2.9.1 Class 1 and 2 cross-sections (1),(2),(3),(4),(5),(6) 6.2.9.2 Class 3 cross-sections 6.2.9.3 Class 4 cross-sections (2) 6.2.10 Bending, shear and axial force (1),(2),(3) 6.3 Buckling resistance of members 6.3.1 Uniform members in compression 6.3.1.1 Buckling resistance (1),(2),(3),(4) 6.3.1.2 Buckling curves (1),(2),(4) 6.3.1.3 Slenderness for flexural buckling (1),(2) 6.3.1.4 Slenderness for torsional and torsional-flexural buckling (1),(2),(3) 6.3.2 Uniform members in bending 6.3.2.1 Buckling resistance (1),(2),(4) 612

Steel Member Design 6.3.2.2 Lateral torsional buckling curves – General case (1),(2),(4) 6.3.2.3 Lateral torsional buckling for rolled sections or equivalent welded sections (1),(2) 6.3.2.4 Simplified assessment methods for beams with restraints in buildings (1),(2),(3) 6.3.3 Uniform members in bending and axial compression (2),(3),(4),(5) Annex A – Method 1: interaction factors kij for interaction formula in 6.3.3(4) Annex B – Method 2: interaction factors kij for interaction formula in 6.3.3(4) UK National Annex to Eurocode EN 1993-1-1:2005 NA.2.15 Partial safety factors for buildings NA.2.16 Imperfection factors for lateral torsional buckling NA.2.17 Lateral torsional buckling for rolled sections or equivalent welded sections NA.2.18 Modification factor, f NA.2.19 The slenderness limit lambdac0 NA.2.20 Modification factor, kfl NA.2.21 Interactions factor kyy,kyz,kzy and kzz NA3.1 BS EN 1993-1-1:2005, Annex A NA3.2 BS EN 1993-1-1:2005, Annex B Eurocode EN 1993-1-1:1992 Annex F: Lateral torsional buckling Eurocode EN 1993-1-5:2006 Plated structural elements 4 Plate buckling effects due to direct stresses at the ultimate limit state 4.1 General 4.2 Resistance to direct stresses 4.3 Effective cross section (3),(4) 4.4 Plate elements without longitudinal stiffeners (1),(2) 5 Resistance to shear 5.1 Basis (1),(2) 5.2 Design resistance (1) 5.3 Contribution from the web (1),(3)a 5.5 Verification 7 Interaction 7.1 Interaction between shear force, bending moment and axial force (1),(2),(4) UK National Annex to Eurocode EN 1993-1-5:2005 NA.2.4 Basis Eurocode EN 1993-1-8:2005 Design of joints 3.10.3 Angles connected by one leg and other unsymmetrically connected members in tension (1),(2) 4.13 Angles connected by one leg (1),(2),(3) 613


Limit state equations used 6.2.3 Tension (6.5) page 49 – section 6.2.4 Compression (6.9) page 49 – section 6.2.5 Bending moment (6.12) page 50 – section 6.2.6 Shear (6.17) page 50 – section, shear (6.19) page 51 – section, shear 6.2.9 Bending and axial force (6.31) page 54 – section (6.41) page 55 – section (6.44) page 56 – section 6.3.1.1 Compression buckling resistance (6.46) page 56 - member 6.3.2.1 Bending buckling resistance (6.54) page 60 - member 6.3.3 Uniform members in bending and axial compression (6.61) page 65 – member (6.62) page 65 – member EN 1993-1-5:2006 5 Resistance to shear (5.10) page 25 – section, shear EN 1993-1-5:2006 7.1 Interaction between shear force, bending moment and axial force (7.1) page 28 – section, shear Assumptions Torsion is not considered. No block or shear lag effects considered. Hybrid girders not considered. Webs are unstiffened. Flange bolt holes equally divided between flanges. Web bolt holes equally divided between webs where applicable. If the design calculates a high Ultimate Load Factor then a default failure equation (Yield about xx axis) will be returned. 3.2.6 G = 80769.231. 6.2.3(5) Tension – Channels connected only through the web and tees connected only through the flange, the effective area is taken as the effective area of the connected element plus half the area of the outstanding elements. 6.2.6(2) check is done even if there is torsion (torsion is not considered). 6.2.6(5) smallest flange area used. 6.2.9.1(4) I, channel and box shapes considered. 6.2.9.2(1) equation (6.44) used. 6.3.2.2(2) Mcr is calculated using EN 1993-1-1:1992 Annex F, including channel and unequal angles. Table A.2 Cmi0 based on member group. Table B3 the highest Cm value calculated for uniform or concentrated load is used. Table B.3 Cmy based on member group. Table B.3 Cmz based on member segment. Table B.3 CmLT based on member segment. EN 1993-1-5:2006 5.2 Design resistance to shear – No contribution from flanges allowed. EN 1993-1-8:2005 3.10.3 – 1 bolt, 1 row assumed.

614

Steel Member Design

AS/NZS 4600:2005 code specific items Sections considered AS/NZS 4600:2005 Cold-formed steel structures (incorporating amendment 1) SECTION 1 SCOPE AND GENERAL 1.1 SCOPE (thickness) 1.3 DEFINITIONS 1.3.5 Bend 1.5 MATERIALS 1.5.1.4 Ductility (fu/fy ratio) 1.6 DESIGN REQUIREMENTS 1.6.3(a) Design capacity Table 1.6 (b),(c),(d),(e),(f) SECTION 2 ELEMENTS 2.1 SECTION PROPERTIES 2.1.1 General 2.1.2 Design procedures 2.1.2.1 Full section properties 2.1.2.2 Effective section properties (b) local instabilities 2.1.3 Dimensional limits 2.1.3.1 Maximum flat-width-to-thickness ratios (a)(i),(b),(c) 2.1.3.4 Maximum web depth-to-thickness ratio (a) unreinforced webs 2.2 EFFECTIVE WIDTHS OF STIFFENED ELEMENTS 2.2.1 Uniformly compressed stiffened elements 2.2.1.1 General 2.2.1.2 Effective width for capacity calculations (a),(c),(i),(ii) 2.2.1.3 Effective width for deflection calculations (a) Procedure I 2.2.3 Stiffened elements with stress gradient 2.2.3.1 General 2.2.3.2 Effective width for capacity calculations 2.2.3.3 Effective width for deflection calculations 2.3 EFFECTIVE WIDTHS OF UNSTIFFENED ELEMENTS 2.3.1 Uniformly compressed unstiffened elements 2.3.1.1 General 2.3.1.2 Effective width for capacity calculations 2.3.1.3 Effective width for deflection calculations 2.3.2 Unstiffened elements and edge stiffeners with stress gradient 2.3.2.1 General 2.3.2.2 Effective width for capacity calculations 2.3.2.3 Effective width for deflection calculations 2.4 EFFECTIVE WIDTH OF UNIFORMLY COMPRESSED ELEMENTS WITH AN EDGE STIFFENER 2.4.1 General 2.4.2 Effective width for capacity calculations 2.4.3 Effective width for deflection calculations

615

SPACE GASS 12 User Manual SECTION 3 MEMBERS 3.1 GENERAL 3.2 MEMBERS SUBJECT TO AXIAL TENSION 3.2.1 Design for axial tension 3.2.2 Nominal section capacity 3.2.3 Distribution of forces 3.2.3.1 End connections providing uniform force distribution 3.2.3.2 End connections providing non-uniform force distribution 3.3 MEMBERS SUBJECT TO BENDING 3.3.1 Bending moment 3.3.2 Nominal section moment capacity 3.3.2.1 General 3.3.2.2 Based on initiation of yielding 3.3.3 Nominal member moment capacity 3.3.3.1 General 3.3.3.2 Members subject to lateral buckling 3.3.3.2.1 Open section members 3.3.3.2.2 Closed box members 3.3.3.3 Members subject to distortional buckling 3.3.3.4 Beams having one flange through-fastened to sheeting 3.3.4 Shear 3.3.4.1 Shear capacity of webs without holes 3.4 CONCENTRICALLY LOADED COMPRESSION MEMBERS 3.4.1 General 3.4.2 Sections not subject to torsional or flexural-torsional buckling equation 3.4.2(1) only 3.4.3 Doubly- or singly-symmetric sections subject to torsional or flexural-torsional buckling 3.4.4 Point-symmetric sections 3.4.5 Non-symmetric sections 3.4.6 Singly-symetric sections subject to distortional buckling 3.4.7 Columns with one flange through-fastened to sheeting 3.6 CYLINDRICAL TUBULAR MEMBERS 3.6.1 General 3.6.2 Bending 3.6.3 Compression 3.6.4 Combined bending and compression APPENDIX D DISTORTIONAL BUCKLING STRESSES OF GENERAL CHANNELS, LIPPED CHANNELS AND Z-SECTIONS IN COMPRESSION AND BENDING D2 SIMPLE LIPPED CHANNELS IN COMPRESSION D3 SIMPLE LIPPED CHANNELS OR Z-SECTIONS IN BENDING ABOUT THE AXIS PERPENDICULAR TO THE WEB Assumptions fy and fu are read directly from section properties. No reductions or increases in fy from Clause 1.5.1.2 - Strength increase resulting from cold forming, or Clause 1.5.1.4(b) Ductility. Shapes with intermediate stiffeners and stiffened lips are not supported. If they are used then the resulting design or check will be conservative because the effect of the stiffeners will not have been taken into account. Unlipped (plain) Cee flanges are assumed to be an unstiffened element and the web a stiffened element.

616

Steel Member Design Webs of top hats that have edge stiffened bottom flanges are assumed to be a stiffened element (ie. flanges are assumed to provide sufficient edge support to the web to have the web classified as stiffened). A ratio of effective section I to gross section I is included in the design report to provide a deflection factor approximating the increase in gross section deflections at the reported design load forces and moments. The SPACE GASS analysis deflections are based on gross sections. Clause 1.3.39 - a single lateral restraint 'L' not combined with any other flange restraint is not recognised as an effective restraint for a segment as they do not meet the requirements of a partially retrained cross section for a segment. Clause 1.3.39 - a continuous lateral restraint 'C' is recognised as a restraint and assumed to meet the requirements of a partially restrained cross section for a segment. Clause 2.1.1 - full section properties and yield strengths read directly from section properties. Clause 2.1.2.1 - actual shape including bends is used to calculate effective section properties. Clause 2.1.3.1 - failure if elements exceed prescribed ratios, warning given if elements exceed clause note's ratios. Clause 2.1.3.3 - shear lag effects not considered. A warning given if group length < 30 * flange width. Clause 2.2.1.3 - procedure I used, Procedure II not used. Clause 3.2.3.1 - it is assumed (a) and (b) are satisfied for concentric end connections. Clause 3.2.3.2 - for channels connected by flanges only, it is assumed b(i) and b(ii) are satisfied. Clause 3.3.3.2.1(b) - Iyc for zeds taken as geometric axis Iy/2. Clause 3.3.2.3 - section moment capacity based on inelastic reserve capacity NOT considered. Clause 3.3.3 - unequal angles, equation 3.3.3.2(13) used for bending in x and y axis. Clause 3.3.3 - Mo is NOT calculated using a rational flexural-torsional buckling analysis. Clause 3.3.3.3 - only lipped cee, lipped cee back to back and zed sections considered for distortional buckling . Clause 3.3.3.2.1(a) - alternative for Z-sections restrained by sheeting against lateral movement NOT considered. Clause 3.3.3.4 - only (i),(ii),(iii),(iv),(v),(vii)(vii based on group length) requirements are checked, assumed other requirements checked by user. Clause 3.3.4.1 - no shear buckling check on CHS sections. Clause 3.3.4 - for top hat sections, shear in x axis carried by top flange and horizontal component of web, shear in y axis carried by vertical component of the web. Clause 3.4.1 - holes have not been allowed for in the calculation of Ae for Nc. Clause 3.4.2 - grade 550 shapes less than 0.9mm thickness not supported. Clause 3.4.2 - clause notes not applied. User to specify effective lengths in steel member design group properties. Clause 3.4.3 - alternative equation 3.4.3(2) not considered. Clause 3.4.3 - equal angles, if no area reduction due to fy, foc based on maximum compressive length and smallest radius of gyration in either axis. Clause 3.4.6 - only lipped single or back to back cee considered for axial compression distortional buckling. Clause 3.4.6 - Fod calculated using Appendix D2. Clause 3.4.7 - s = 0.5 (fastener in centre of flange), smallest flange width used for zed sections. Clause 3.4.7 - only (i),(ii),(iii),(iv),(v),(vi),(ix),(x based on group length) requirements are checked, assumed other requirements checked by user. Clause 3.5 - equations 3.5.1(2) and 3.5.2(2) are included in section checks. Msx and Msy are used in equation 3.5.1(2)for the section check. Clause 3.5.1 - equations 3.5.1(1) and 3.5.1(2) are included in member checks, equation 3.5.1(3) is used if N*/phicNc <= 0.15. Clause 3.5.1 - actual group length used for L in the L/1000 centroid shift for angles. Clause 3.5.2 - equation 3.5.2(1) is included in member checks only.

617

SPACE GASS 12 User Manual Clause 3.5.2 - equation 3.5.2(1) the axial tension term is conservatively ignored (N* is always zero) if axial tension exists. Clause 3.6.3 - axial compression section capacity for CHS is based on gross area. Appendix D - for zeds, the widest flange is used determining flange and lip properties. Appendix D - flange and lip properties represented as square corners and centrelines. Appendix D3 - no reduction in lambda for any bracing interval.

618

Steel Member Design

IS800 code specific items Sections considered IS800 : 2007 - General Construction in Steel - Code of Practice (Third Revision) SECTION 2 MATERIALS 2.1 General 2.2 Structural Steel 2.2.4 Properties SECTION 5 LIMIT STATE DESIGN 5.4 Strength 5.4.1 Design strength 5.5 Factors Governing the Ultimate Strength 5.6 Limit State of Serviceability SECTION 6 DESIGN OF TENSION MEMBERS 6.1 Tension Members 6.2 Design Strength Due to Yielding of Gross Section 6.3 Design Strength Due to Rupture of Critical Section SECTION 7 DESIGN OF COMPRESSION MEMBERS 7.1 Design Strength 7.3 Design Details 7.3.1 Thickness of Plate Elements 7.3.2 Effective Sectional Area (Ae) SECTION 8 DESIGN OF MEMBERS SUBJECTED TO BENDING 8.2 Design Strength in Bending (Flexure) 8.4 Shear 8.6 Design of Beams and Plate Girders with Solid Webs 8.6.1.1a and 8.6.1.2a Minimum web thickness when transverse stiffeners are not provided 8.6.2 Sectional Properties 8.10 Bending in a Non-Principal Plane 8.10.2 Member loaded in a non-principal plane SECTION 9 MEMBER SUBJECTED TO COMBINED FORCES 9.1 General 9.2 Combined Shear and Bending 9.3 Combined Axial Force and Bending Moment SECTION 12 DESIGN AND DETAILING FOR EARTHQUAKE LOADS 12.1 General 12.2 Load and Load Combinations 12.5 Columns 12.7 Ordinary Concentrically Braced Frames (OCBF) 12.8 Special Concentrically Braced Frames (SCBF) 12.9 Eccentrically Braced Frames (EBF) 12.10 Ordinary Moment Frames (OMF) 12.11 Special Moment Frames (SMF) ANNEX E ELASTIC LATERAL TORSIONAL BUCKLING E-1 Elastic Critical Moment

619


Steel member design/check errors SPACE GASS performs numerous checks for illegal and inconsistent data. Many of these checks are done in the steel member design data input modules and any errors detected there must be corrected immediately. However, some errors such as faulty member groupings cannot be detected until the design/check phase. All of the errors in the following list cause SPACE GASS to abort the design or check of the current design group and move on to the next group. If an error occurs during a design or an uninterrupted check, the program continues without alerting you and puts the error message in the output report. Alternatively, if an error occurs during an interrupted check, the program pauses to display the message and, if it is a section related error, gives you the opportunity to manually select other sections to be checked. Warnings also appear in the output report but they do not cause SPACE GASS to abort the design or check of the current design group. This group contains a non-existent or repeated member One of the analysis members nominated in the design group does not exist or has been repeated. Members in this group are not of the same section type All analysis members in the design group must have the same section property number. This group does not have a contiguous run of members All of the analysis members nominated in the design group must be connected together endto-end in the frame analysis model. They must also be listed in the design group in the order that they are connected (from either end). A tens/comp-only member in this group is disabled One of the analysis members in the design group is a tension-only or compression-only member which has been disabled during the analysis, thus leaving a gap in the group. A member in this group has buckled One of the analysis members in the design group has buckled during the analysis, thus leaving a gap in the group. Stations per member limit has been exceeded The stations per analysis member limit has been exceeded or the stations per design group limit has been exceeded. There is a limit of 500 stations per analysis member which must be enough for the number of intermediate member stations that you specify, plus the extra stations at the ends, at concentrated member loads and at flange restraint points. The solution is to either add a node at midspan of the analysis member which has too many stations or decrease the number of stations that you specify at the start of the member design/check phase. A flange restraint is off the end of the member group One or more flange restraints have been specified beyond the end of the design group. Inappropriate group code or shape not supported The section data from the library has an invalid group code or shape code (see also Section libraries).

620

Steel Member Design Starred angles cannot be made up from unequal angles Starred angles can only be made from equal angle sections. Starred angles are not supported for this design code This is a restriction in the AS4100, BS5950 and NZS3404 modules. This section shape not supported for this design code The selected steel member design module does not support the shape of the section currently being designed or checked. Inappropriate end connection code for this section An end connection code which is inappropriate for the section being considered has been input. For example, an I or H section can have end codes of "Flange(s)", "Web" or "Centroid", or a single angle section can have end codes of "Short" or "Long". Note that single angle sections cannot have end connection codes of "Centroid". If eccentric effects for angles are to be ignored, they must be disabled at the start of the member design/check phase. Invalid fabrication code for this section The section data from the library has an invalid fabrication code (see also Section libraries) or a rolled section has a fabrication code which shows it to be welded. Inappropriate section dimensions for this design code A code specific constraint on section dimensions has not been met. For example, the BS5950 module requires channels to have equal flanges. For dimension constraints, see also Steel member design/check assumptions. No suitable section found The steel member design module has found that all sections from the library which comply with the library scan code are inadequate. WARNING: You have suppressed eccentric end connection effects If eccentric end effects for members which are not connected concentrically have been disabled at the start of the design/check phase then this warning appears in the output report. WARNING: Not all load cases considered have been analysed non-linearly For AS4100 and NZS3404, a warning appears in the output report if any member design/check load cases have only been analysed linearly. WARNING: Web is inadequate for combined actions (App I) (Lf=#.##) For AS4100 and NZS3404, a warning appears in the output report if the web is inadequate. It suggests that web stiffeners may be required. The web failure load factor is also given. WARNING: Angle calculations do not consider bending moments. Do a manual check For AS1250, SABS0162 and AS3990, the calculations for angle sections do not consider bending moments (apart from eccentric end moments). They should be checked manually.

621

Steel Connection Design Steel connection design The SPACE GASS steel connection design module lets you design or check any of the connections in a structural model.

Some key features of the module are as follows:         

Fully integrated into SPACE GASS. Design actions obtained directly from the analysis results. Multiple load cases considered simultaneously. Design and checking modes available. Fully rendered 3D images of each connection generated. Annotated elevations detailing all the connection components. Connections able to be exported to other programs. Fully compliant with the 2007 - 2014 ASI Steel Connection Design Guides. All bolts, welds, plates, cleats, stiffeners and doubler plates designed/checked.

A video showing the steel connection design module in action can be viewed at www.spacegass.com/connect.

623

SPACE GASS 12 User Manual Note that if you haven't purchased the steel connection design module, you can still run it in a free trial mode that limits you to using minimum design actions, and prevents you from exporting or saving the job. All other features are fully activated. The connection design module is currently limited to open sections, however connections for closed (tubular) sections are currently under development and are expected to become available in the second half of 2014. Refer to "Creating and editing connections", "The connection manager", "Design considerations", "Connection reports" and "Connection preferences" for full details of the connection design module.

624

Steel Connection Design

Creating and editing connections In order to define a steel connection, it is simply a matter of selecting the members to be connected, clicking the right mouse button and then selecting "Input/Edit Steel Connection" from the menu that appears or by clicking the button in the top toolbar and then selecting "Input/Edit Steel Connection". Note that most connections require two members to be selected, however for base plates, single member stiff seats and some of the tubular connections, only one member needs to be selected.

You must then select the type of connection you want from the following table. Connections that are invalid for the number of members you selected will be disabled in the table.

625


Alternatively, if you wish to make it the same as a connection that has already been created, you can click the "Copy from Existing Connection" button and then select from a list of the existing connections.

626


Note that if your model already contains connections, you can see which ones are attached to a particular member by selecting that member, clicking the right mouse button, choosing "Steel Connection Design" from the menu and, if the selected member already has connections they will be displayed in the following table. You can then click "Add New Connection" to create a new connection for that member or edit one of its existing ones.

Regardless of which of the above methods you used, the connection is then designed (or checked if you have copied from an existing connection) and the results are presented in the connection editor shown below.

627


From there, you can examine the connection, click the Ok button to save and exit if you happy with it, or make changes to customize it to your exact requirements. Connection viewer The connection viewer in the right-hand side of the editor gives you a realistic 3D rendered view of the connection. You can zoom, pan and rotate the image using the mouse in the normal way.

Or you can click the buttons at the top of the connection viewer to do a "Zoom fit", display annotated 2D elevations or switch back to the 3D rendered image.

628


629


Input/edit fields In order to edit the connection, you can change any of the data fields in the left-hand side panel. Some of the key input fields are as follows:

Connection number This is the unique identification number of each connection. By default it is set to the node number at the connection, however if that number is already taken by another connection then it uses the next available number. You can manually set it to comply with whatever numbering scheme you prefer. Design code Currently only AS4100 is available. Title You can specify an optional title that helps you to identify each connection. If you leave it blank then the connection is referred to by its number and connection type. Supporting and supported member These are the members that are connected to each other. When you first create the connection, SPACE GASS automatically determines which member is the supporting member and which one is supported, however if you wish to swap them you can do so in this form. You can also set the strength for each of the members. Connection type If you wish to change the connection type to one of a similar category then you can do so with this field. For example, you could change a bolted end plate to a welded moment connection or a web side plate to a flexible end plate, however you couldn't change a bolted end plate to a web side plate because they are in different categories. If you wish to change to a connection of a different category then you must click the "Change Connection Type" button on the right side of the editor and then re-select from the table of connection types. Stiffen web/flange if necessary Ticking these options means that web or flange stiffeners will be included in a design only if required. If you untick these options and stiffeners are required then the connection will fail. Stiffen end plate If you tick this option then the end plate will always be stiffened and this may result in a thinner end plate than would otherwise be required.

630

Steel Connection Design Load cases If you want to consider all load cases then this field should be left blank, otherwise you should type in your desired list of load cases (separated by commas or dashes). Alternatively, you can click the "..." button to the right of the input field and then select the load cases you want from the list that appears as shown below.

Minimum design actions In order to ensure that each connection is well proportioned and robust, especially when the analysis design actions are quite low, the code nominates minimum design actions that should be complied with. Normally you would leave this option ticked, however you can turn it off if required. Note that if you haven't purchased the steel connection design module, you can still run it in a free trial mode that limits you to using minimum design actions. When running in this mode, any load cases you type into the "Load cases" field are ignored and you can't turn off the "Minimum design actions" option. Haunches, plates, welds, bolts, stiffeners and cleats The remainder of the input fields involving haunches, plates, bolts, stiffeners and cleats are connection dependent. You can change any of them to configure a connection to exactly what you want. Any fields with a library button give you access to the relevant library for the type of data being input. Designing and checking When you first create a connection, it is automatically designed and the results are presented in the connection editor. You can either accept it in that state or you can proceed to make changes and then have it checked.

If you change one of the input fields that could be overwritten by a design, the connection becomes locked. This is a safety feature that guards against you inadvertently clicking the "Design" button and losing your changes. If you really want to design the connection after making changes that lock it then you must first click the padlock button to unlock it.

631


Note that some input fields do not cause the connection to be locked, as they are input fields only and are not overwritten when you perform a design. Examples of these are bolt strength, bolting procedure, weld strength, etc. Locking a connection If you wish to prevent any further changes to a connection that isn't already locked, you can lock it by clicking the padlock button. This will stop any of the components of the connection from being changed if a batch design is performed via the connection manager.

Auto check If the "Auto check" option is ticked then a check is automatically done as soon as you make a change to any component of your connection. If it is unticked then no checking is done until you click the "Check" button. Status bar The status bar at the bottom of the editor indicates whether the connection has passed, failed or passed with a warning. It includes the critical load case, the utilization ratio and a brief explanation of the failure mode or warning message. A green line indicates it has passed, red indicates failure and yellow is for a pass with a warning message. All of these colors can be changed via the "Preferences" button.

Key diagrams The symbols used in the connection input fields match the ASI design guides, however some of the commonly used ones are also shown in key diagrams that you can view by clicking the "Key Diagram" button.

632


Hiding components If you wish to examine components of the connection that may be difficult to see or partially obscured, you can turn on or off the members, plates, bolts or welds using the buttons shown below. They are all on by default.

633


Reset If you wish to undo all the changes made to a connection (except for its connection number and title), you can click the "Reset" button. This will put it back to its default state, the same as if you deleted the connection and then re-created it. Reports A single report (including a graphical representation of the connection) for the connection currently in the editor can be obtained by clicking the "Report" button. Alternatively, you can generate text reports for multiple connections via the report panel of the connection manager or via the normal SPACE GASS report generator in the non-renderer window. Refer to "Connection reports" for more information. Exporting You can export the current connection to a CAD system via the "DXF" or "DWG" buttons. It can then be imported into AutoCAD or any other program that supports those formats. Preferences The "Preferences" button lets you change various connection parameters and colors. For more information refer to "Connection preferences".

634

Steel Connection Design Infotips Once you have created some connections, you can hover over a node or member in your model to see which connections are attached to it.

635


The connection manager The connection manager is at the heart of the steel connection design module. It presents all of your connections in a table and lets you scroll through them, viewing each one as you go. You can also delete connections, edit them, generate reports or perform a batch design/check on multiple connections. You can get to the connection manager by clicking the renderer or via its Design menu.

button in the top toolbar of the

Connection table You can click on any connection in the table to see it in the connection manager viewer or you can scroll through them by using the up and down arrow keys on your keyboard. You can double-click any connection in the table to open it in the connection editor or alternatively you could use the "Edit Connection" button at the bottom of the table. The colored blocks in the first column signify whether the connection has passed (green), failed (red), passed with a warning (yellow) or has not yet been designed or checked (white). If the colored block contains a small padlock then it means that the connection is locked and cannot be designed unless you unlock it first or tick the "Include locked connections" option below when designing in batch mode. By hovering over the colored block for a particular connection you can obtain its critical load case, utilization ratio, failure mode (if failed) or warning message (if there is one). Note that any of the colors can be changed via the "Preferences" button.

636

Steel Connection Design The second column indicates whether the connection has been design ("D") or checked ("C"). The remaining columns list the members involved in each connection, the connection type and its title. Connections can be added or deleted by using the "Add Connection" or "Delete Connection" buttons at the bottom. It is recommended that new connections are added by using the procedure explained in "Creating and editing connections" rather than via the "Add Connection" button here.

Batch design/check You can use this section of the manager to design or check all of your connections or just some of them. This will be required from time to time if your model has been changed and/or re-analysed.

Connections If you want to design/check all connections then this field should be left blank, otherwise you should type in your desired list of connections (separated by commas or dashes).

637

SPACE GASS 12 User Manual Alternatively, you can click the "..." button to the right of the input field and then select the connections you want from the list that appears as shown below.

Load cases If you want to consider all load cases then this field should be left blank, otherwise you should type in your desired list of load cases (separated by commas or dashes). Alternatively, you can click the "..." button to the right of the input field and then select the load cases you want from the list that appears as shown below.

Check Tick this option if you want the locked connections (marked with in the first column) to be checked. These are the connections that have been locked manually via the padlock button or locked automatically due to changes made to them in the connection editor. They will simply be checked for adequacy and none of their components or design parameters will be changed during the check. Note that if the "Design" option is unticked then the locked and unlocked connections will be checked.

638

Steel Connection Design Design Tick this option if you want the unlocked connections (not marked with in the first column) to be designed. During the design some of their components may be changed if the model or the design actions have changed since the last design. Include locked connections If you want to override any locked connections and design them anyway then you should tick this option. During the batch design/check, all the connections encountered that are locked will be designed instead of being checked, however at the end they will be re-locked. Note that any changes you have made to the connection components will be lost during this process. Skip connections already designed or checked If you have a large number of connections in your model, you may be able to save some design/check time by ticking this option to skip the ones that have already been designed or checked. For most jobs this time saving will be minimal and so you should generally leave it unticked. Reports Text reports for multiple connections can be generated by filling out the following form and then clicking the "Generate Report" button. Alternatively, you can click the "Report" button in the connection editor to obtain a report (including a graphical representation of the connection) for the connection currently in the editor. You can also obtain text reports via the normal SPACE GASS report generator in the non-renderer window. Refer to "Connection reports" for more information.

Exporting and importing connections Connection data can be exported to various file formats including MS-Excel and MS-Access. You can also import from MS-Excel and MS-Access. To export from the connection table you should select all of the connections to be exported, click the right mouse button, select "Export" and then choose the desired export format. To import, just click the right mouse button and choose "Import". Note that the data being exported/imported is limited to the connection number, the associated member numbers, the connection type and its title. None of the detailed connection data is included. This means that any changes you have made to a connection will not be included in the exported file and will be lost if you then re-import the file. For designed connections however, once you import the data and re-design the connections, all of the detailed connection data will be reinstated.

639


Preferences The "Preferences" button lets you change various connection parameters and colors. For more information refer to "Connection preferences".

640


Design considerations Design procedure The design procedure varies for each connection type, however the general procedure is as follows: 1. An initial plate size is chosen from the plate library, starting with the smallest size. 2. An initial bolt size and bolt count is chosen from the bolt library, starting with the smallest size. The bolt count depends on the bolt size, the plate size and the connection type. 3. An initial weld is chosen from the weld library, starting with the smallest size. 4. A number of checks are performed to determine the adequacy of each component and the overall adequacy of the connection. If everything passes then the design stops. If not, it continues as follows. 5. If any weld checks fail, the weld size is incremented (or is changed from a fillet to a butt weld) and the procedure returns to step 4. If the maximum weld size has been reached without a solution, the procedure continues as follows. 6. If any bolt checks fail, the bolt size is incremented and the procedure returns to step 3. If the maximum bolt size has been reached without a solution, the procedure continues as follows. 7. If any plate checks fail, the plate size is incremented and the procedure returns to step 2. If the maximum plate size has been reached without a solution then the connection fails. Note that the actual procedure is somewhat more complicated than described above due to the differing nature of the interaction between the plates, bolts and welds for each connection type. Design actions Some of the design actions that occur at a connection are not relevant for every connection type. The design actions considered for each connection type are listed in the following table. Fx (Axial force) Open Connections Bolted end plate Welded moment Bolted apex Fully bolted splice Fully welded splice Bolted / welded splice Web side plate Flexible end plate Bolted angle cleat Bolted angle seat Welded angle seat Bearing pad Stiff seat Pinned baseplate

     



Fy (Major axis shear)              

Fz (Minor axis shear)

Mx (Torsion)



641

M

SPACE GASS 12 User Manual Moment baseplate Tubular Connections Slotted end plate Welded tee end plate Flattened end Bolted end plate splice Bolted moment end plate KN gap KN overlap KT gap KT overlap Mitred knee







         

         

         

Note that tubular connections containing a gusset plate and involving multiple members consider the shear forces and moments generated by the eccentricity of the connected members. Zero member strength During a connection design/check, the module also checks that the member has sufficient section capacity to transfer the design actions to the connection. If you get an error message stating that "The supporting or supported member has zero strength...", it means that the member's Fy or Fyw value is zero. To fix this, you should open the shape builder for the member in question, click the "Design Properties" button and then ensure that the Fy and Fyw values are non-zero. Note that if the Fy and Fyw are already non-zero, it means that the shape builder has obtained them and put them into the fields for you. You should save the new properties, re-analyse the model and then try the connection design again.

642


Connection reports Text reports can be generated via the following form in the connection manager, via the normal SPACE GASS report generator in the non-renderer window or via the "Report" button in the connection editor. After specifying which connections are to be included in the report and ticking the other desired options in the above form, you should click the "Generate Report" button.

The following report is for a single connection that was generated from within the connection editor.

643


644


Connection preferences You can change the defaults for various connection parameters such as dimensions, size ranges, strength grades, colors and other options. Note that not all parameters are used in all connections. For example, the default bolt gauge is overridden by other requirements in the bolted end plate connection and others. The bolt size, weld size and plate thickness ranges limit the size of the bolts, welds and plates in a design and allow you to exclude sizes that are unavailable or not desired. Most colors can also be changed and you can see the immediate effect of your changes in the sample image on the right and in the sample pass/warning/fail status bars at the bottom.

645

Concrete Beam Design Concrete beam design The SPACE GASS reinforced concrete beam design module lets you design or check any reinforced concrete beams in a structural model.

Some key features of the module are as follows:              

Fully integrated into SPACE GASS. Design actions obtained directly from the analysis results. Multiple load cases considered simultaneously. Design and checking modes available. Fully rendered 3D images and 2D cross sections of each beam designed or checked. Flexural and shear reinforcement designed or checked. Rectangular, "T" and "L" cross sections are supported. Development lengths calculated. Straight, hooked or cogged bar ends. Moment, shear, torsion, deflection, seismic and fire considerations taken into account. Priority settings available for "minimum steel", "minimum layers" or "minimum bars". Moment redistribution available. Reinforcing bar libraries. Fully compliant with AS3600 and IS456.

A video showing the reinforced concrete beam design module in action can be viewed at www.spacegass.com/rcbeam. Note that if you haven't purchased the concrete beam module, you can still run it in a free trial mode that limits you to using predefined cross section dimensions, and prevents you from exporting or saving the job. All other features are fully activated. Refer to "Creating and editing concrete beams", "The concrete manager" and "Concrete beam preferences" for full details of the concrete beam design module. 647


648

Concrete Beam Design

Creating and editing concrete beams In order to define a concrete beam, it is simply a matter of selecting the members that make up the beam, clicking the right mouse button and then selecting "Input/Edit Concrete Beam" from the menu that appears or by clicking the "Input/Edit Concrete Beam".

button in the top toolbar and then selecting

Note that the reinforced concrete beam module does not let you input the cross section shape or dimensions. The cross section geometry is taken from the beam's section properties and must have been defined earlier by you using the shape builder.

The beam is then designed and the results are presented in the concrete beam editor shown below.

649


From there, you can examine the beam, click the Ok button to save and exit if you happy with it, or make changes to customize it to your exact requirements. Before accepting the design results, you must ensure that the beam's supports have been correctly detected! See "Supports" below for further information. The status bar The status bar at the bottom of the editor indicates whether the beam has passed, failed or passed with a warning. It includes the critical load case, the critical zone, the utilization ratio and a brief explanation of the failure mode or warning message. A green line indicates it has passed, red indicates failure and yellow is for a pass with a warning message. All of these colors can be changed via the "Preferences" button.

Blue may also be used in some circumstances to display other types of messages.

650

Concrete Beam Design Data panel The data panel on the left of the beam editor lets you make changes to the design data which are then reflected in the diagrams and tables in the concrete beam editor. More information about specific items in the data panel is presented in the following sections below.

651


652


Checking and Designing When you first create a beam and open it in the beam editor it does an initial design and then displays "Design" at the end of the status bar. If you make changes that initiate a check or if you click the "Check" button then "Check" is displayed at the end of the status bar instead.

Many of the input parameters affect both checks and designs (eg. ultimate load case list, minimum design actions, cover, etc), whereas other parameters are design-specific (eg. design priorities, bar size ranges, etc) or check-specific (eg. bar sizes, layers, etc). If you change a parameter that affects both checks and designs then the previous action (ie. check or design) will be repeated, whereas if you change a check-specific or design-specific parameter then it will perform the action appropriate for that change. Each time you make a change that triggers an automatic re-design or re-check there is a small pause while the action is performed. If you don't want this to happen or if it becomes annoying you should untick the "Auto" option at the bottom and then just click the Design or Check buttons whenever you're ready.

If you have made changes to the reinforcement or layers then the beam will become locked to guard against you accidently performing a design and losing your changes. If you really want to do a design then you must click the red locked button first to unlock it.

General data In this panel you can specify the beam number, design code, descriptive title, analysis member list, load case lists and torsion switch. The beam number and analysis member list are normally predefined based on which members you selected when you created the concrete beam, however you can change them here if required. It is important that you correctly specify the load case lists and don't just leave them blank. The ultimate load cases are the ones that the strength design is based on and they are usually the combination load cases that have been factored up to ultimate. The serviceability load cases are used to calculate the short term deflections based on the cracked moments of inertia. They are usually the short term primary live load and wind load cases. Finally, the sustained load cases are used to calculate the long term deflections based on creep and usually consist of just the long term dead loads. Neither the serviceability or sustained load cases are used in the design calculations. If you leave the ultimate load case list blank then all analysed load cases will be considered, whereas if you leave the serviceability or sustained load case lists blank then they will not be considered, effectively rendering them inactive. If you wish to consider torsion then you should tick the "Torsion" checkbox. Enabling torsion requires extra longitudinal reinforcement to resist the torsion moment. For AS3600 you can specify "Indirect" torsion if torsional strength is not required for the equilibrium of the 653

SPACE GASS 12 User Manual structure and the torsion in the beam is induced solely by the angular rotation of adjoining members. For further information refer to AS3600 clause 8.3.2.

When specifying load case lists, you can either list them directly, or you can click the "..." button to display and select from a list of the load cases currently in the job as shown below.

Minimum design actions In order to guarantee a robust design, most concrete design codes impose lower limits on the design actions. You can comply with these limits for positive and/or negative moments.

Design priorities When performing a design, the module evaluates many solutions (sometimes hundreds), discards the impractical ones and then sorts the rest according to the "Design Priority" setting that you have selected. For example, if you have selected "Minimum bars" then it will put the solution that has the minimum number of bars first and present that as the optimal solution. "Minimum steel" gives the most efficient design in terms of total area of steel, however it usually results in many different bar sizes throughout the beam and so is often impractical. "Minimum layers" or "Minimum bars" give the best results in most circumstances.

654


Beam data panel The information in this panel applies to the whole beam. By default there are five "Zones per span", consisting of a zone at the supports at each end of the span plus three zones in the span. You can change the number of zones per span or, if you want different numbers of zones in some spans, you should click the "..." button and specify the number of zones in each span individually. If you tick the "Same bar size in all zones" option then a bar that continues through multiple zones will maintain a constant size. For "T" or "L" beams, if the top bars don't fit inside the stirrups and "Keep inside stirrups" is not ticked then the excess bars will be placed in the slab or flange. During the shear design, the stirrups are kept at the size you specify and only their spacing is changed. The stirrup size is always constant for the entire beam. The "Top and bottom bar size ranges" simply limit the size of bars that will be used in a design. The "Layer spacing" is the centerline distance between bars in adjacent layers. For AS3600, the "Crack control" requirements are more stringent if the beam is in an exterior environment. For further information refer to AS3600 clause 8.6.1. For IS456, the "Effective width" of a "T" or "L" beam depends on whether the beam is integrated with a slab or is an isolated beam. For further information refer to IS456 clause 23.1.2.

Zones By default there are five zones per span, consisting of a zone at the supports at each end of the span plus three zones in the span. The number of zones per span can be changed in the beam data panel described above. In the zones panel you can change the current zone by selecting it in the "Zone" field at the top or you can cycle through them by clicking the "Prev" or "Next" buttons. The current zone

655

SPACE GASS 12 User Manual is highlighted in the beam view panel at the top, in the bending moment, shear force or deflection diagram in the middle, and in the cross section panel. For each zone you can specify the number of layers, the bars per layer and the bar sizes. You can also specify the stirrup details and, for AS3600, the Vuc criterion for crack control in accordance with clause 8.2.7.4. Whenever you make changes to the reinforcement or layers, the changes are locked to guard against you doing an accidental design and losing your changes. If you really want to perform a design you must first unlock the beam before you can click the "Design" button as described in "Checking and Designing" above. The "Minimum top/bot steel (% of max)" parameters place a lower limit on the area of steel in the current zone based on a percentage of the maximum area of steel used elsewhere in the beam. For example, if the maximum top area of steel in the beam is 2575mm^2 and you have specified a "Min top steel (% of max)" of 33% then the top area of steel for that zone will be limited to no less than 850mm^2. The "Copy to all zones" buttons allow you to copy the data from the current zone to all other zones in the beam.

Development lengths Development lengths are calculated automatically based on the bar size, bar type, end anchorage, concrete properties and bar stress. They are included in the reports and are displayed in the beam view panel. To see them more clearly you can turn them on or off in the beam view panel by clicking the "View development lengths" button.

Bar anchorage Bars can be left straight at the ends of the beam or they can be hooked or cogged.

656


Cover The cover is specified as the clear distance from the edge of the bars and stirrups to the edge of the concrete.

Moment redistribution Moment redistribution allows you to reduce the bending moments at the supports with a resulting increase in the span moments. It is generally only applied to the internal supports of statically indeterminate beams, but you can also choose to redistribute the moments at the beam's end supports if appropriate. When moment redistribution is activated you must choose the amount of redistribution and specify whether that amount applies at the support centerlines or at the faces of the supports. During moment redistribution the shear forces are also adjusted to maintain static equilibrium. Moment redistribution should be used with utmost care and if used inappropriately could result in unsafe designs. You should ensure that there is adequate rotation capacity in critical moment regions to allow the assumed redistribution of bending moments to be achieved.

Supports The beam's supports are automatically detected based on node restraints and steps in the shear force diagram, however it is possible that for some beams, supports may be missed or nonexistent supports may be detected. The supports are shown in the bending moment, shear force and deflection diagrams as small black triangles and so it is easy for you to visually see if they are correct or not. Because the beam design or check relies on knowing where the supports are, it is imperative that the supports are correct before you accept any results.

657


If a support occurs at a node that doesn't have a vertical node restraint, such as if the beam is supported on columns or other beams, it is detected by measuring the upwards step in the shear force diagram and if the shear step exceeds the "Shear step threshold" percentage then a support is assumed to exist at that location. The shear step threshold is determined by calculating the maximum shear force anywhere in the beam from all analysed load cases and then multiplying it by the threshold percentage that you specify. 5% has been found to produce good results, but if supports are being missed or non-existent supports are being detected then you should adjust the threshold until all the supports are found correctly.

Beam view panel The panel at the top of the beam editor shows a 3D side view of the entire beam. By clicking on any part of the beam you can select a zone so that its reinforcement and other details are shown in the data panel on the left, and its dimensions and reinforcement are displayed in the cross section panel at the bottom of the editor.

You can also zoom, pan and rotate the beam to show the dimensions, cross section and reinforcement in more detail.

658


You can also click the "2D View" tab to display a 2D drawing of the beam.

The buttons at the top of the panel let you do a "zoom fit" or quickly switch to a side view or "30,10" view. You can also turn on/off the stirrups, main bars, development lengths or dimensions for a clearer view.

Moment, shear and deflection diagrams The diagram in the middle panel by default shows the bending moment envelope for the ultimate load cases. By clicking the radio buttons at the top you can change it to show the envelopes for the serviceability or sustained load cases instead. You can also switch it to show shears or deflections by clicking the tabs at the top. After a design, the critical zone is selected and is shown shaded in the moment, shear and deflection diagrams. You can also click on any zone in the diagram to select that zone so that its reinforcement and other details are shown in the data panel on the left, and its dimensions and reinforcement are displayed in the cross section panel at the bottom of the editor. The green lines above and below the bending moment envelope represent the bending capacity of the beam and give a very good indication of how efficient your beam design is. The closer they track the bending moment envelope the more efficient your beam design is. Note however that if torsion is included then the capacity lines may overstate the bending

659

SPACE GASS 12 User Manual capacity because some of the steel will be required to resist torsion and will not be available for bending. In this case there will be a gap between the bending moment envelope and the capacity lines, with the gap representing the reduction in bending capacity due to the torsion requirement. If minimum design actions govern then there may also be a significant gap between the capacity lines and the moment envelope.

You can hover the mouse cursor over any part of the diagram to show the underlying values at the cursor's location.

You can also zoom the diagram by placing the mouse cursor at the desired location and then using the mouse scrollwheel. If the zoom feature doesn't work then it is because the diagram doesn't have focus, in which case you should click on it and then try again.

The shear tab displays the shear force envelope for the ultimate load cases.

660


The deflections tab displays the elastic, short term, long term and total deflections based on the "Serviceability" and "Sustained" load cases specified above the diagrams. The elastic deflections match the deflections from the SPACE GASS analysis and are based on the serviceability load cases using the gross moment of inertia (Ig). The short term deflections are also based on the serviceability load cases but using the cracked moment of inertia (Iefs), whereas the long term deflections are based on the sustained load cases using the moment of inertia adjusted for creep (Iefl). You can see graphs of Ig, Iefs and Iefl by clicking the "Ig, Ief" radio button. The total deflections are the sum of the short term and long term deflections. Note that all deflections displayed in the diagram include the free body movement of the beam based on the elastic deflections of the supports and so if you are manually checking the total deflections by simply summing the short and long term deflections you must also subtract the deflections at the supports so that they are not doubled up. If your supports have short term or long term deflections that are significantly different to their elastic deflections, such as if the beam is supported on other beams for example, then you may need to adjust the short and long term deflections along the beam to allow for those support deflections.

The lines below the deflection curves are based on the L/d limits you can specify in the data panel to provide an indication of whether the deflections are excessive or not. Note that the L/d limits are purely for your visual checking and are not used in the design calculations.

661


Cross section panel The cross section panel shows the shape, dimensions and reinforcement for the currently selected zone. You can select a different zone by clicking it in the beam view panel at the top or by selecting it in the data panel on the left.

You can also click the "DXF/DWG" or "Save Image" buttons on the right side of the editor to export the cross section to a DWG or DXF file, or save the cross section image to a metafile (EMF) file. An EMF file can be used to generate a high quality image with no pixilation regardless of how much it is enlarged.

Reinforcement and output panel The panel at the bottom-right shows a summary of the reinforcement for the entire beam.

You can also click the Output tab to show a list of the main checks and variables used in the design/check.

662


Preferences You can click the "Preferences" button to open the concrete beam preferences form and then change the defaults for various concrete parameters such as the default bar library, dimensions, clearances, zones, cover, size ranges, design priorities, code specific parameters, colors and other options.

Reports The reports button lets you generate various types of reports for the concrete beam.

To see a video that shows the reinforced concrete beam module in action, visit www.spacegass.com/rcbeam.

663


The concrete manager The concrete manager is at the heart of the reinforced concrete beam, column and footing modules. It presents all of your beams, columns and footings in a table and lets you scroll through them, viewing each one as you go. You can also delete beams, columns and footings, edit them, generate reports or perform a batch design/check on multiple beams, columns and footings. You can get to the concrete manager by clicking the renderer or via its Design menu.


Beams/columns/footings table You can click on any beam, column or footing in the table to see it in the concrete manager viewer or you can scroll through them by using the up and down arrow keys on your keyboard. You can double-click any item in the table to open it in the editor or alternatively you could use the "Edit..." button at the bottom of the table. The colored blocks in the first column signify whether the beam, column or footing has passed (green), failed (red), passed with a warning (yellow) or has not yet been designed or checked (white). If the colored block contains a small padlock then it means that the item is locked and cannot be designed unless you unlock it first or tick the "Include locked beams/columns/footings" option below when designing in batch mode. By hovering over the colored block for a particular item you can obtain its critical load case, critical zone, utilization ratio, failure mode (if failed) or warning message (if there is one). Note that any of the colors can be changed via the "Preferences" button. The second column indicates whether the beam, column or footing has been design ("D") or checked ("C"). The remaining columns list the item number, the members involved and the title.

664

Concrete Beam Design Beams, columns and footings can be added or deleted by using the "Add..." or "Delete..." buttons at the bottom. It is recommended that new beams are added by using the procedure explained in "Creating and editing concrete beams" rather than via the "Add..." button here.

Batch design/check You can use this section of the manager to design or check all of your beams, columns and footings or just some of them. This will be required from time to time if your model has been changed and/or re-analysed.

Beams/columns/footings If you want to design/check all items these fields should be left blank, otherwise you should type in your desired list of beams, columns or footings (separated by commas or dashes). Alternatively, you can click the "..." button to the right of the input fields and then select the items you want from the list that appears as shown below.

665



The following options let you decide which beams, columns and footings should be checked or designed.

Check Tick this option if you want the locked items (marked with in the first column) to be checked. These are the items that have been locked manually via the padlock button or locked automatically due to changes made to their reinforcement or layers in the editor. They will 666

Concrete Beam Design simply be checked for adequacy and none of their input parameters will be changed. Note that if the "Design" option is unticked then both the locked and unlocked items will be checked. Design Tick this option if you want the unlocked items (not marked with in the first column) to be designed. During the design their reinforcement may be changed if the model or the design actions have changed since the last design. Include locked beams/columns/footings If you want to override any locked beams, columns or footings and design them anyway then you should tick this option. During the batch design/check, all the items encountered that are locked will be designed instead of being checked, however at the end they will be re-locked. Note that any changes you have made to reinforcement or layers will be lost during this process. Skip beams/columns/footings already designed or checked If you have a large number of beams, columns or footings in your model, you may be able to save some design/check time by ticking the "Skip..." option shown below to skip the ones that have already been designed or checked.

Reports Text reports for multiple beams, columns and footings can be generated by filling out the following form and then clicking the "Generate Report" button. Alternatively, you can click the "Report" button in the editor to obtain a report (including a graphical representation of the beam, column or footing) for the item currently in the editor. You can also obtain text reports via the normal SPACE GASS report generator in the non-renderer window.

Exporting and importing Beam, column and footing data can be exported to various file formats including MS-Excel and MS-Access. You can also import from MS-Excel and MS-Access. To export from the table you should select all of the items to be exported, click the right mouse button, select "Export" and then choose the desired export format. To import, just click the right mouse button and choose "Import".

667

SPACE GASS 12 User Manual Note that the data being exported/imported is limited to the beam/column/footing number, the associated member numbers and the title. None of the detailed data is included. This means that any changes you have made to a beam, column or footing will not be included in the exported file and will be lost if you then re-import the file. For designed beams, columns and footings however, once you import the data and re-design the items, all of the detailed data will be reinstated.

Preferences The "Preferences" button lets you change various beam, column and footing parameters and colors. For more information refer to "Concrete beam preferences".

668


Concrete beam preferences You can change the defaults for various concrete parameters such as the default bar library, dimensions, clearances, zones, cover, size ranges, design priorities, code specific parameters, colors and other options. The bar size ranges limit the size of the reinforcing bars in a design and allow you to exclude sizes that are unavailable or not desired. Most colors can also be changed and you can see the immediate effect of your changes in the sample image on the right and in the sample pass/warning/fail status bars at the bottom.

669


670


AS3600 2009 code specific items for beams Sections considered AS3600-2009 Concrete Structures Code (incorporating amendments 1 and 2) SECTION 1 SCOPE AND GENERAL 1.1 SCOPE AND APPLICATION 1.1.2 Application (a)(i) SECTION 2 DESIGN PROCEDURES, ACTIONS AND LOADS 2.2 DESIGN FOR STRENGTH 2.2. Strength check procedure for use with linear elastic methods of analysis (ii) Table 2.2.2 2.3 DESIGN FOR SERVICEABILITY (Informative only) SECTION 3 DESIGN PROPERTIES OF MATERIALS 3.1 PROPERTIES OF CONCRETE 3.1.1 Strength 3.1.1.1 Characteristic compressive strength (a) 3.1.1.3 Tensile strength 3.1.2 Modulus of elasticity (c) Table 3.1.2 3.1.4 Stress-strain curve (a) 3.1.7 Shrinkage (Informative only) 3.1.7.1 Calculation of design shrinkage strain (c) 3.1.7.2 Design shrinkage strain 3.2 PROPERTIES OF REINFORCEMENT 3.2.2 Modulus of elasticity (a) SECTION 5 DESIGN FOR FIRE RESISTANCE (Informative only) 5.2 DEFINITIONS 5.2.1 Average axis distance 5.2.2 Axis distance 5.4 FIRE RESISTANCE PERIODS (FRPs) FOR BEAMS 5.4.1 Structural adequacy for beams incorporated in roof or floor systems (a),(b) SECTION 6 METHODS OF STRUCTURAL ANALYSIS 6.2 LINEAR ELASTIC ANALYSIS 6.2.3 Critical sections for negative moments (optional) 6.2.7 Moment redistribution in reinforced and prestressed members for strength design 6.2.7.2 Deemed-to-comply approach for reinforced and prestressed members SECTION 8 DESIGN OF BEAMS FOR STRENGTH AND SERVICEABILITY 8.1 STRENGTH OF BEAMS ON BENDING 8.1.1 General 8.1.2 Basis of strength calculations 8.1.3 Rectangular stress block 8.1.5 Design strength in bending 671

SPACE GASS 12 User Manual (b) 8.1.6 Minimum strength requirements 8.1.6.1 General 8.1.9 Spacing of reinforcement and tendons 8.2 STRENGTH OF BEAMS IN SHEAR 8.2.1 General 8.2.2 Design shear strength of a beam (a),(c) 8.2.4 Maximum transverse shear at support 8.2.5 Requirements for shear reinforcement (a),(b) 8.2.6 Shear strength limit by web crushing 8.2.7 Shear strength of a beam excluding shear reinforcement 8.2.7.1 Reinforced beams 8.2.8 Minimum shear reinforcement 8.2.9 Shear strength of a beam with minimum reinforcement 8.2.10 Contribution to shear strength by the shear reinforcement (a),(b) 8.2.12 Detailing of shear reinforcement 8.2.12.1 Types (a) 8.2.12.2 Spacing 8.3 STRENGTH OF BEAMS IN TORSION 8.3.1 General 8.3.2 Secondary torsion 8.3.3 Torsional strength limited by web crushing 8.3.4 Requirements for torsional reinforcement (a),(b) 8.3.5 Torsional strength of a beam (a),(b) 8.3.6 Longitudinal torsional reinforcement (a),(b) 8.3.7 Minimum torsional reinforcement (a),(b),(i),(ii) 8.3.8 Detailing of torsional reinforcement (a),(b),(c) 8.5 DEFLECTION OF BEAMS (Informative only) 8.5.1 General 8.5.3 Beam deflection by simplified calculations 8.5.3.1 Short-term deflection (a),(b),(c) 8.5.3.2 Long-term deflection 8.6 CRACK CONTROL OF BEAMS (Informative only) 8.6.1 Crack control for tension and flexure in reinforced beams (a),(b),(d),(i),(ii) 8.6.3 Crack control in the side face of beams 8.8 T-BEAMS AND L-BEAMS 8.8.2 Effective width of flange for strength and serviceability (a),(b) SECTION 13 STRESS DEVELOPMENT OF REINFORCEMENT AND TENDONS (Informative only) 13.1 STRESS DEVELOPMENT IN REINFORCEMENT 13.1.1 General 13.1.2 Development length for a deformed bar in tension 672

Concrete Beam Design 13.1.2.1 Development length to develop yield strength 13.1.2.2 Basic development length 13.1.5 Development length of deformed bars in compression 13.1.5.1 Development length to develop yield strength 13.1.5.2 Basic development length APPENDIX C REQUIREMENTS FOR STRUCTURES SUBJECT TO EARTHQUAKE ACTIONS C4.2 Beams C4.2.1 Longitudinal reinforcement (a),(b),(i),(ii) C4.2.2 Shear reinforcement (a),(b) Assumptions Serviceability and deflection results are informative only. No serviceability or deflection limit checks control the results. Clause 3.1.1.3 - f'ct.f is taken as 0.6(f'c)^0.5. Clause 3.1.2 - Ec is taken from Table 3.1.2 for standard f'c values, where f'c is taken from the material properties of the member in the SPACE GASS model. For non-standard f'c values, Ec is taken from the material properties of the member in the SPACE GASS model. fsy and reinforcement ductility is taken from the SPACE GASS reinforcing bar library. If the section contains a mixture of bars with different fsy and ductility values, the fsy and ductility of the first bar on the bottom layer is used. Fire resistance results are informative only. No fire resistance limit checks control the results. Clause 6.2.3 - Optional preference to reduce maximum negative bending moment at support. Clause 8.1.6 - Optional setting to comply with minimum design actions for positive and/or negative moments. Clause 8.1.9 - User specified preference for minimum clear bar distance. Clause 8.1.10.3 - Not checked, but a zone setting is available for design mode where the user can specify minimum steel top and bottom based on a percentage of the steel required for the respective maximum moment along the entire beam. Clause 8.2.4 - Optional preference to specify location or not. No checks done for 8.2.4(b)(i),(ii), or (iv). Clause 8.2.5(a) - In design mode, shear reinforcement at 300 centres is always provided. Clause 8.2.7.4 - A zone setting is provided to set Vuc to be equal to zero, else Vuc will be calculated as per normal code requirements. Clause 8.2.12.2 - Transverse spacing only checked for single fitments, transverse spacing not checked for double fitments. Clause 8.3.2 - A beam setting is provided to specify if the torsion being applied is an indirect (secondary) torsion or direct torsion. If indirect is chosen, the torsion capacity is still calculated for informative purposes only. 673


Clause 8.3.8(b) - Closed fitments are assumed if torsion is to be considered. Only spacing check is considered. Clause 8.5.3.1 - The gross I can be optionally based on the steel transformed to an equivalent concrete area or just on a homogeneous section. The alternative equation for Ief is not used. Clause 8.5.3.2 - The alternative kcs method is used to calculate additional long term deflection. The Asc/Ast is based on each specific zone reinforcement. Clause 8.6.1 - Crack control is informative only. No crack control limit checks control the results. Clause 8.8 - No checks are done for flange-web connection capacities of T and L beams. Clause 13.1 - Development length calculations are informative only.

674


IS456 2000 code specific items for beams Sections considered IS456:2000 Plain and Reinforced Concrete Code of Practice (Fourth Revision) SECTION 2 MATERIALS, WORKMANSHIP, INSPECTION AND TESTING 5 MATERIALS 5.3 Aggregates 5.3.3 Size of Aggregate 6 CONCRETE 6.2 Properties of Concrete 6.2.2 Tensile Strength of Concrete 6.2.3 Elastic Deformation 6.2.4 Shrinkage 6.2.5 Creep of Concrete 6.2.5.1 (Creep Coefficient) 21 FIRE RESISTANCE 21.2 Minimum Requirement of Concrete Cover 22 ANALYSIS 22.1 General 22.2 Effective Span 26 REQUIREMENTS GOVERNING REINFORCEMENT AND DETAILING 26.2 Development of Stress in Reinforcement 26.2.1 Development Length of Bars 26.3 Spacing of Reinforcement 26.3.2 Minimum Distance Between Individual bars 26.3.3 Maximum Distance Between Bars in Tension (a) Beams 26.4 Nominal Cover to Reinforcement 26.4.3 Nominal Cover to Meet Specified Period of Fire Resistance 26.5 Requirements of Reinforcement for Structural Members 26.5.1 Beams 26.5.1.1 Tension Reinforcement 26.5.1.2 Compression Reinforcement 26.5.1.5 Maximum Spacing of Shear Reinforcement 26.5.1.6 Minimum Shear Reinforcement 26.5.1.7 Distribution of Torsion Reinforcement SECTION 5 STRUCTURAL DESIGN (LIMIT STATE METHOD) 37 ANALYSIS 37.1 Analysis of Structure 37.1.1 Redistribution of Moments in Continuous Beams and Frames 38 LIMIT STATE OF COLLAPSE: FLEXURE 38.1 Assumptions 40 LIMIT STATE OF COLLAPSE: SHEAR 40.2 Design Shear Strength of Concrete 40.2.1 Beams 40.3 Minimum Shear Reinforcement 40.5 Enhanced Shear Strength of Sections Close to Supports 41 TORSION 41.1 General 41.2 Critical Section 41.3 Shear and Torsion 41.4 Reinforcement in Members Subjected to Torsion 675

SPACE GASS 12 User Manual 43 LIMIT STATE OF SERVICEABILITY: CRACKING 43.1 Flexural Members ANNEX C: CALCULATION OF DEFLECTION C-1 TOTAL DEFLECTION C-2 SHORT-TERM DEFLECTION C-3 DEFLECTION DUE TO SHRINKAGE C-4 DEFLECTION DUE TO CREEP Assumptions Serviceability and deflection results are informative only. No serviceability or deflection limit checks control the results. If there are bars with different fy values, the fy design is the fy of the first bar at the bottom layer and the design/check process assumes all bars have the same fy. Clause 5.3.3 - Size of aggregate: The default aggregate size is 20 mm, but the user can change the value (General Preferences). Clause 6.2.5.1 - Creep coefficient: The user has options for creep coefficients. Clause 22.2 - Effective span is assumed to be centre-to-centre between supports. Clause 22.6 - Critical sections for moment and shear: The user has the option to take the moment and shear at the face of the support or at a user-defined distance from the face of the support. Clause 26.2 - Development lengths are calculated so that at any point within the considered zone the bond capacity between concrete and steel is sufficient to carry the maximum tensile or compressive stress in the zone. Clause 26.3.2c - The requirement for vertical spacing between layers of reinforcement is not checked. Clause 26.5.1.3 - The side face reinforcement for crack control is not checked. Clause 38.1c - A rectangular stress block is assumed: The uniform stress level = 0.4 * fck (Ref: P.C. Varghese, "Limit State Design of Reinforced Concrete", Second Edition, Chapter 5). The depth of the stress block is to the neutral axis. The uniform stress level already includes the partial safety factor 1.5 for concrete. The design compressive strength of concrete = 0.66 of the characteristic strength of concrete. Clause 41 - Torsion: Closed fitments are assumed if torsion is to be considered. If there is torsion, the actions (V* and M*) have been increased based on the code requirements to take into account the torsion effects.

676

Concrete Column Design Concrete column design The SPACE GASS reinforced concrete column design module lets you design or check any reinforced concrete columns in a structural model.

Some key features of the module are as follows: 677


           

Fully integrated into SPACE GASS. Design actions obtained directly from the analysis results. Multiple load cases considered simultaneously. Design and checking modes available. Fully rendered 3D images and 2D cross sections of each column designed or checked. Flexural and shear reinforcement designed or checked. Circular, rectangular, tee, trapezoidal, cruciform and flat oval cross sections are supported. Multiple voids of any shape or size. Moment (uniaxial and biaxial) and shear considerations taken into account. Calculation and display of interaction curves. Reinforcing bar libraries. Fully compliant with AS3600 and IS456.

A video showing the reinforced concrete column design module in action can be viewed at www.spacegass.com/rccolumn. Note that if you haven't purchased the concrete column module, you can still run it in a free trial mode that limits you to using predefined cross section dimensions, and prevents you from exporting or saving the job. All other features are fully activated. Refer to "Creating and editing concrete columns", "The concrete manager" and "Concrete column preferences" for full details of the concrete column design module.

678

Concrete Column Design

Creating and editing concrete columns In order to define a concrete column, it is simply a matter of selecting the members that make up the column, clicking the right mouse button and then selecting "Input/Edit Concrete Column" from the menu that appears or by clicking the selecting "Input/Edit Concrete Column".

button in the top toolbar and then

Note that the reinforced concrete column module does not let you input the cross section shape or dimensions. The cross section geometry is taken from the column's section properties and must have been defined earlier by you using the shape builder.

The column is then designed and the results are presented in the concrete column editor shown below.

679


From there, you can examine the column, click the Ok button to save and exit if you happy with it, or make changes to customize it to your exact requirements.

The status bar The status bar at the bottom of the editor indicates whether the column has passed, failed or passed with a warning. It includes the critical load case, the utilization ratio and a brief explanation of the failure mode or warning message. A green line indicates it has passed, red indicates failure and yellow is for a pass with a warning message. All of these colors can be changed via the "Preferences" button.

Blue may also be used in some circumstances to display other types of messages.

Data panel The data panel on the left of the column editor lets you make changes to the design data which are then reflected in the diagrams and tables in the concrete column editor. More information about specific items in the data panel is presented in the following sections below.

680


Checking and Designing When you first create a column and open it in the column editor it does an initial design and then displays "Design" at the end of the status bar. If you make changes that initiate a check or if you click the "Check" button then "Check" is displayed at the end of the status bar instead.

Many of the input parameters affect both checks and designs (eg. ultimate load case list, minimum design actions, cover, etc), whereas other parameters are design-specific (eg. design priorities, bar size ranges, etc) or check-specific (eg. bar sizes, bar counts, etc). If you change a parameter that affects both checks and designs then the previous action (ie. check or design) 681

SPACE GASS 12 User Manual will be repeated, whereas if you change a check-specific or design-specific parameter then it will perform the action appropriate for that change. Each time you make a change that triggers an automatic re-design or re-check there is a small pause while the action is performed. If you don't want this to happen or if it becomes annoying you should untick the "Auto" option at the bottom and then just click the Design or Check buttons whenever you're ready.

If you have made changes to the reinforcement then the column will become locked to guard against you accidently performing a design and losing your changes. If you really want to do a design then you must click the red locked button first to unlock it.

General data In this panel you can specify the column number, design code, descriptive title, analysis member list, load case list, and the biaxial bending and shear check switches. The column number and analysis member list are normally predefined based on which members you selected when you created the concrete column, however you can change them here if required. The ultimate load cases are the ones that the strength design is based on and they are usually the combination load cases that have been factored up to ultimate. If you leave this list blank then all analysed load cases will be considered. Biaxial bending checks are important and so you should always tick the "Biaxial bending check" option unless you specifically want to check uniaxial moments only. For circular columns, the normal procedure for handling biaxial moments is to combine them into a single moment at an angle to the cross section axes and then just treat it as a uniaxial moment problem. You can do this by ticking the "Combine Mx and My moments" option. For circular columns with "Combine Mx and My" unticked or non-circular columns, the biaxial checks are done using the equations in AS3600 clause 10.6.4 or IS456 clause 39.6. Note that because AS3600 clause 10.6.4 applies to rectangular sections only, you should perform your own independent checks if you have biaxial moments in non-circular columns or non-combined moments in circular columns. Shear in columns rarely governs, however if you wish to consider shear then you should tick the "Shear check" check box. If shear is being checked then you must also specify a shear area ratio (see below).

682


When specifying load case lists, you can either list them directly, or you can click the "..." button to display and select from a list of the load cases currently in the job as shown below.

Minimum design actions In order to guarantee a robust design, most concrete design codes impose lower limits on the design actions. The minimum design actions can be calculated automatically based on code specific requirements or you can click the "Custom" option and then specify them manually. AS3600

IS456

Moment magnifiers Moment magnifiers (AS3600) or additional moments (IS456) are calculated automatically if the "Calculate" options are ticked, otherwise you can specify them manually. For AS3600, the moment magnifiers are affected by whether the column is braced or unbraced as defined in the "Column effective lengths" panel below and by whether the design actions are from a linear or non-linear analysis. If braced or non-linear analysis, the moment magnifier is calculated in accordance with equation 10.4.2, using the value of d that you specify. For an unbraced column with a linear analysis, the moment magnifier is also based

683

SPACE GASS 12 User Manual on uc in equation 10.4.3(2). uc should be set by you based on the results of a buckling analysis using reduced section properties of 0.4Ec.If for flexural members and 0.8Ec.Ic for columns. A handy way of applying the reduced section properties is to give the flexural members and the columns separate concrete materials in your SPACE GASS model and then manually reducing the Ec for each material to 0.4Ec and 0.8Ec respectively before performing the buckling analysis. Note that for a non-linear analysis, uc is not used. AS3600

IS456

Column effective lengths Column effective lengths are not calculated automatically! They are based on the column's overall length multiplied by the kx and ky factors that you specify in this panel. The "Braced" options (AS3600 only) affect how the moment magnifiers are calculated (see above) and whether or not the column is deemed to be "short" or "slender" based on clause 10.3.1. They do not affect the column effective length calculations.

Shear area ratio If shear is being checked then the effective area of the cross section resisting shear must be known. This is calculated by multiplying the shear area ratio (Av/Ag) by the gross cross sectional area (Ag). You should check that the ratio is correct for the cross section shape and the governing shear direction.

Reinforcement When performing a concrete column design, SPACE GASS calculates the optimal reinforcement (subject to the steel range % and bar size range limits that you specify at the top of the reinforcement panel) and presents it in the lower part of the panel. If you have the "Auto" option at the bottom of the form ticked and the column is not locked (ie. the padlock button at the bottom is green) then whenever you make a change to any of the design parameters, the reinforcement could change. If you manually change any of the bar counts or sizes in this panel then the column will become locked (ie. the padlock button at the bottom will become red) and any further changes you make to the design parameters will simply cause the reinforcement to be checked rather than be changed. Alternatively, if you wish to lock the bar counts, but still allow the bar sizes

684

Concrete Column Design to change then you could tick the "Lock bar count" option. In this case a re-design could cause the bar sizes to change but the number of bars would remain as they were.

If you wish to change the size of all your bars, you can click the library button (circled below) in the "Total bars" row and then select a new size from the reinforcing bar library. Sometimes this row will also contain the word "Variable" if you have a mixture of different bar sizes in your column.

If you wish to change the position or size of individual bars then you can click the "Bar Table" button and then make your changes in the table below. The bar table also lets you add, delete or generate bars, or unify the bar sizes.

685


Design priorities When performing a design, the module evaluates many solutions (sometimes hundreds), discards the impractical ones and then sorts the rest according to the "Design Priority" setting that you have selected. For example, if you have selected "Minimum bars" then it will put the solution that has the minimum number of bars first and present that as the optimal solution. "Minimum steel" gives the most efficient design in terms of total area of steel, however it usually results in quite small bar sizes and so is often impractical. "Minimum bars" gives the best result in most circumstances.

Column view panel The panel at the top of the column editor shows a 3D or 2D view of the entire column.

686


687


You can also zoom, pan and rotate the column to show the dimensions, cross section and reinforcement in more detail.

The buttons at the top of the panel let you do a "zoom fit" or quickly switch to a side view or "30,10" view. You can also turn on/off the stirrups, main bars or dimensions for a clearer view.

Interaction diagram The interaction diagram represents the capacity of the column in terms of its axial load versus moment envelope. Interaction curves are included for the actual reinforcement (shown in red) together with the 1%, 2%, 3% and 4% reinforcement percentages. Note that you can vary the 1%, 2%, 3% and 4% values via the concrete column preferences form if you wish to change the steel percentages for the extra curves. Each load case is shown as a green dot in the diagram and should fall within the red curve. If a load dot falls outside the red curve then failure has occurred. Note that the interaction diagram applies to uniaxial moments only and so you could get a biaxial failure even if all the load dots fall within the curve. The special points labelled as "Ecc", "Dec" and "Bal" are defined as follows:

688

Concrete Column Design Ecc: The minimum eccentricity point that coincides with M=e.N, where e is the minimum eccentricity, M is the moment and N is the axial compression. e = 0.05D for AS3600 (clause 10.1.2) and e = max(L/500 + D/30, 20mm) for IS456 (clause 25.4). If minimum moments are complied with then all the load points should be located on the high moment side of the line connecting the origin with the Ecc point. Dec: The decompression point that coincides with the extreme tension fibre being zero. This is the point at which it switches from being partially in tension to fully in compression. Bal: The balanced point at which the tensile steel reaches yield. This is the point at which it switches from a compression failure to a tension failure.

You can hover the mouse cursor over any part of the diagram to show the underlying values at the cursor's location.

You can also zoom the diagram by placing the mouse cursor at the desired location and then using the mouse scrollwheel. If the zoom feature doesn't work then it is because the diagram doesn't have focus, in which case you should click on it and then try again.

689


Panels to the right of the interaction diagram let you combine the curves for positive and negative moments or turn on/off various display options.

690

Concrete Column Design Confinement region (AS3600 only) The confinement region is defined by AS3600 as the "Region where the design action effects of combined axial force and bending on a section require confinement to the core". If a load falls within the confinement region and f'c does not exceed 50MPa then SPACE GASS provides confinement to the core in the form of fitments that comply with clause 10.7.4. If a load falls within the confinement region and f'c exceeds 50MPa then SPACE GASS treats this as a failure.

Cross section panel The cross section panel shows the shape, dimensions and reinforcement for the currently selected zone. You can select a different zone by clicking it in the beam view panel at the top or by selecting it in the data panel on the left.

You can also click the "DXF/DWG" or "Save Image" buttons on the right side of the editor to export the cross section to a DWG or DXF file, or save the cross section image to a metafile (EMF) file. An EMF file can be used to generate a high quality image with no pixilation regardless of how much it is enlarged.

Voids Multiple voids of any shape or size can be included in the cross section and taken into consideration in the column calculations. You simply add them as negative shapes in the shape builder when you are creating your cross section for the analysis model. 691


Preferences You can click the "Preferences" button to open the concrete column preferences form and then change the defaults for various concrete parameters such as the default bar library, spacings, cover, size ranges, colors and other options.

Reports The reports button lets you generate a concise or a full report for the concrete column.

To see a video that shows the reinforced concrete beam module in action, visit www.spacegass.com/rccolumn.

692


The concrete manager The concrete manager is at the heart of the reinforced concrete beam, column and footing modules. It presents all of your beams, columns and footings in a table and lets you scroll through them, viewing each one as you go. You can also delete beams, columns and footings, edit them, generate reports or perform a batch design/check on multiple beams, columns and footings. You can get to the concrete manager by clicking the renderer or via its Design menu.


Beams/columns/footings table You can click on any beam, column or footing in the table to see it in the concrete manager viewer or you can scroll through them by using the up and down arrow keys on your keyboard. You can double-click any item in the table to open it in the editor or alternatively you could use the "Edit..." button at the bottom of the table. The colored blocks in the first column signify whether the beam, column or footing has passed (green), failed (red), passed with a warning (yellow) or has not yet been designed or checked (white). If the colored block contains a small padlock then it means that the item is locked and cannot be designed unless you unlock it first or tick the "Include locked beams/columns/footings" option below when designing in batch mode. By hovering over the colored block for a particular item you can obtain its critical load case, utilization ratio, failure mode (if failed) or warning message (if there is one). Note that any of the colors can be changed via the "Preferences" button. The second column indicates whether the beam, column or footing has been design ("D") or checked ("C"). The remaining columns list the item number, the members involved and the title.

693

SPACE GASS 12 User Manual Beams, columns and footings can be added or deleted by using the "Add..." or "Delete..." buttons at the bottom. It is recommended that new columns are added by using the procedure explained in "Creating and editing concrete columns" rather than via the "Add..." button here.

Batch design/check You can use this section of the manager to design or check all of your beams, columns and footings or just some of them. This will be required from time to time if your model has been changed and/or re-analysed.

Beams/columns/footings If you want to design/check all items these fields should be left blank, otherwise you should type in your desired list of beams, columns or footings (separated by commas or dashes). Alternatively, you can click the "..." button to the right of the input fields and then select the items you want from the list that appears as shown below.

694



The following options let you decide which beams, columns and footings should be checked or designed.

Check Tick this option if you want the locked items (marked with in the first column) to be checked. These are the items that have been locked manually via the padlock button or locked automatically due to changes made to their reinforcement or layers in the editor. They will 695

SPACE GASS 12 User Manual simply be checked for adequacy and none of their input parameters will be changed. Note that if the "Design" option is unticked then both the locked and unlocked items will be checked. Design Tick this option if you want the unlocked items (not marked with in the first column) to be designed. During the design their reinforcement may be changed if the model or the design actions have changed since the last design. Include locked beams/columns/footings If you want to override any locked beams, columns or footings and design them anyway then you should tick this option. During the batch design/check, all the items encountered that are locked will be designed instead of being checked, however at the end they will be re-locked. Note that any changes you have made to reinforcement or layers will be lost during this process. Skip beams/columns/footings already designed or checked If you have a large number of beams, columns or footings in your model, you may be able to save some design/check time by ticking the "Skip..." option shown below to skip the ones that have already been designed or checked.

Reports Text reports for multiple beams, columns and footings can be generated by filling out the following form and then clicking the "Generate Report" button. Alternatively, you can click the "Report" button in the editor to obtain a report (including a graphical representation of the beam, column or footing) for the item currently in the editor. You can also obtain text reports via the normal SPACE GASS report generator in the non-renderer window.

Exporting and importing Beam, column and footing data can be exported to various file formats including MS-Excel and MS-Access. You can also import from MS-Excel and MS-Access. To export from the table you should select all of the items to be exported, click the right mouse button, select "Export" and then choose the desired export format. To import, just click the right mouse button and choose "Import".

696

Concrete Column Design Note that the data being exported/imported is limited to the beam/column/footing number, the associated member numbers and the title. None of the detailed data is included. This means that any changes you have made to a beam, column or footing will not be included in the exported file and will be lost if you then re-import the file. For designed beams, columns and footings however, once you import the data and re-design the items, all of the detailed data will be reinstated.

Preferences The "Preferences" button lets you change various beam, column and footing parameters and colors. For more information refer to "Concrete column preferences".

697


Concrete column preferences You can change the defaults for various concrete parameters such as the default bar library, spacings, cover, size ranges, colors and other options. The bar size ranges limit the size of the reinforcing bars in a design and allow you to exclude sizes that are unavailable or not desired. Most colors can also be changed and you can see the immediate effect of your changes in the sample image on the right and in the sample pass/warning/fail status bars at the bottom.

698


AS3600 2009 code specific items for columns Sections considered AS3600-2009 Concrete Structures Code (incorporating amendments 1 and 2) SECTION 1 SCOPE AND GENERAL 1.1 SCOPE AND APPLICATION 1.1.2 Application (a)(i) SECTION 2 DESIGN PROCEDURES, ACTIONS AND LOADS 2.2 DESIGN FOR STRENGTH 2.2. Strength check procedure for use with linear elastic methods of analysis (ii) Table 2.2.2 2.3 DESIGN FOR SERVICEABILITY (Informative only) SECTION 3 DESIGN PROPERTIES OF MATERIALS 3.1 PROPERTIES OF CONCRETE 3.1.1 Strength 3.1.1.1 Characteristic compressive strength (a) 3.1.1.3 Tensile strength 3.1.2 Modulus of elasticity (c) Table 3.1.2 3.1.4 Stress-strain curve (a) 3.1.7 Shrinkage (Informative only) 3.1.7.1 Calculation of design shrinkage strain (c) 3.1.7.2 Design shrinkage strain 3.2 PROPERTIES OF REINFORCEMENT 3.2.2 Modulus of elasticity (a) SECTION 8.2 STRENGTH OF BEAMS IN SHEAR Shear strength in columns is calculated based on the procedure set out in Section 8.2 SECTION 10 DESIGN OF COLUMNS FOR STRENGTH AND SERVICEABILITY 10.1 GENERAL 10.1.1 Design Strength 10.1.2 Minimum bending moment 10.1.3 Definition 10.1.3.1 Braced column 10.1.3.2 Short column 10.1.3.3 Slender column 10.2 DESIGN PROCEDURES 10.2.1 Design procedure using linear elastic analysis 10.2.2 Design procedure incorporating secondary bending moements 10.3 DESIGN OF SHORT COLUMNS 10.3.1 General 10.4 DESIGN OF SLENDER COLUMNS 10.4.1 General 10.4.2 Moment magnifier for a braced column 10.4.3 Moment magnifier for an unbraced column 699

SPACE GASS 12 User Manual 10.4.4 Buckling load 10.5 SLENDERNESS 10.5.1. General 10.6 STRENGTH OF COLUMNS IN COMBINED BENDING AND COMPRESSION 10.6.2 Strength of cross-sections calculated using the rectangular stress block 10.6.2.2 Squash load 10.6.2.3 Decompression point 10.6.2.4 Transition from decompression point to squash load 10.6.2.5 Transition from decompression point to bending strength 10.6.3 Design for biaxial bending and compression 10.7 REINFORCEMENT REQUIREMENTS FOR COLUMNS 10.7.1 Limitations on longitudinal steel 10.7.2 Functions of fitments (NOTE: shear check included, torsion check NOT included) 10.7.3 Confinement to the core 10.7.3.1 (a) General requirements 10.7.4 Restraint of longitudinal reinforcement 10.7.4.1 (a) General requirements 10.7.4.3 Diameter and spacing of fitments and helices Assumptions Clause 3.1.1.3 - f'ct.f is taken as 0.6(f'c)^0.5. Clause 3.1.2 - Ec is taken from Table 3.1.2 for standard f'c values, where f'c is taken from the material properties of the member in the SPACE GASS model. For non-standard f'c values, Ec is taken from the material properties of the member in the SPACE GASS model. fsy and reinforcement ductility is taken from the SPACE GASS reinforcing bar library. If the section contains a mixture of bars with different fsy and ductility values, the fsy and ductility of the first bar on the bottom layer is used. Clause 8.1.6.1 - If the user has elected to comply with minimum design actions, Equation 8.1.6.1(1) is used even if Ast is sufficient to satisfy Equation 8.1.6.1(2). Clause 10.5.3 - The effective lengths of columns are not automatically calculated by the reinforced concrete module. Instead, the user must provide the effective length factors kx and ky. Clause 10.6.4 - Equation 10.6.4 is used for biaxial bending checks with rectangular, Tee, cruciform, trapezoidal and flat oval cross sections even though it is intended for rectangular cross sections only. It is expected that a future version will offer a method that combines the biaxial moments and calculates an interaction diagram about axes that are aligned with the combined moment. Clause 10.7.2 - Shear checks are automatically performed, however torsion checks are not. The user must manually check if columns are adequate for torsion. Clause 10.7.3.1(b) - If a load falls within the confinement region of a column with f'c > 50MPa it is treated as a failure. In such cases the column strength may pass the AS3600 code checks but the user must ensure that sufficient confinement to the core is provided based on AS3600 10.7.3. Clause 10.7.4.3 - Bundled bars are not considered. Shear checks are based on single stirrups (ie. two legs) even if additional stirrups have been provided to restrain the longitudinal bars. 700


No checks are done to detect bars positioned inside or too close to a void. No checks are done to detect voids positioned too close to the edge of the column.

701


IS456 2000 code specific items for columns Sections considered IS456:2000 Plain and Reinforced Concrete Code of Practice (Fourth Revision) SECTION 2 MATERIALS, WORKMANSHIP, INSPECTION AND TESTING 5 MATERIALS 5.3 Aggregates 5.3.3 Size of Aggregate 6 CONCRETE 6.2 Properties of Concrete 6.2.2 Tensile Strength of Concrete 6.2.3 Elastic Deformation 21 FIRE RESISTANCE 21.2 Minimum Requirement of Concrete Cover 22 ANALYSIS 22.1 General 22.2 Effective Span 26 REQUIREMENTS GOVERNING REINFORCEMENT AND DETAILING 26.4 Nominal Cover to Reinforcement 26.4.2.1 Column Durability 26.5 Requirements of Reinforcement for Structural Members 26.5.3 Columns 26.5.3.1 Longitudinal Reinforcement 26.5.3.2 Transverse Reinforcement SECTION 5 STRUCTURAL DESIGN (LIMIT STATE METHOD) 38 LIMIT STATE OF COLLAPSE: FLEXURE 38.1 Assumptions 39 LIMIT STATE OF COLLAPSE: COMPRESSION 39.1 Assumptions 39.2 Minimum Eccentricity 39.3 Short Axially Loaded Members in Compression 39.5 Members Subjected to Combined Axial Load And Uniaxial Bending 39.6 Members Subjected to Combined Axial Load and Biaxial Bending 39.7 Slender Compression Members 39.7.1 Addition Moments 40 LIMIT STATE of COLLAPSE: SHEAR 40.1 Nominal Shear Stress 40.2 Design Shear Strength of Concrete 40.2.1 Shear Strength of Concrete Without Shear Reinforcement 40.2.2 Shear Strength of Members Under Axial Compression 40.2.3 With Shear Reinforcement 40.3 Minimum Shear Reinforcement Assumptions Clause 38.1c - A rectangular stress block is assumed: The uniform stress level = 0.4 * fck (Ref: P.C. Varghese, "Limit State Design of Reinforced Concrete", Second Edition, Chapter 5). The depth of the stress block is to the neutral axis. The uniform stress level already includes the partial safety factor 1.5 for concrete. The design compressive strength of concrete = 0.66 of the characteristic strength of concrete.

702

Concrete Column Design Clause 41 - Torsion: No torsion checks are performed. Shear checks are based on single stirrups (ie. two legs) even if additional stirrups have been provided to restrain the longitudinal bars. No checks are done to detect bars positioned inside or too close to a void. No checks are done to detect voids positioned too close to the edge of the column.

703

Output Output Text and graphics reports can be viewed or printed. Print previews can be obtained and the page setup form gives you full control over the printer selection, paper size, orientation, margins, layout, scales and output format. You can initiate a report by clicking the toolbar button or selecting the Output menu. You can then choose between viewing a text report, printing a text report or printing graphics. For text reports, the output can be limited to just input data or just output data and even to specific nodes, members, section properties and load cases if required. You can also limit the output to the data specified in any of the graphical filters.

Prior to generating a report, you must choose the items that you want to include in the report by selecting the appropriate check boxes in the above form. You can turn a whole column of check boxes on or off by clicking the "All on" or "All off" buttons at the bottom of the form. After completing your selections, you can proceed to the following form.

705


Filters You can select from any of the graphical filters to limit the output report to the data defined in a filter. Alternatively, you can select "Use Filter Selected in Main Toolbar" so that the data included in the output report always matches what is shown in the graphics display area. You can also further limit the output data by specifying lists of nodes, members, section properties, load cases, etc. If you want to include all items for a particular list then the list field should be left blank, otherwise type in a list of items (separated by commas or dashes) that you want to include in the report. Format Output can be printed in fixed point format (eg. 12.45) or exponential format (eg. 1.245E+01). Fixed point is generally preferred as it is easier to read and allows numbers with different orders of magnitude to be readily identified. It cannot, however be used with very large or very small values. In such cases, exponential format must be used. As well as specifying the format, you can select the number of decimal places to be included. This cannot be greater than 3 for exponential formatting and cannot be greater than 8 for fixed 706

Output point formatting. These limits are imposed because of a maximum 10 digit field width. Care must be taken when specifying the number of decimal places with fixed point format. You must ensure that for the range of values likely to be encountered, you don't exceed the 10 digit field width. For example five decimal place fixed point format could only handle values from -999.99999 to 9999.99999. Values outside of this range would simply be printed as "**********". Section and material properties are always presented in exponential format regardless of the format you specify (due to the extreme range of values usually encountered). Enveloping The analysis results data for each load case can be printed separately or can be combined into a load case envelope. If a load case envelope is specified, the program selects and prints the maximum and minimum values from the list of specified output load cases. The report also includes the load case numbers and the matching coincident values that occur at the same location and load case as each maximum and minimum. At the end of an envelope report is a summary envelope showing the maximums and minimums for a group of nodes and/or members. The summary report also shows the load case numbers and the matching coincident values. Envelope summary only By default, envelope reports include an envelope summary at the end, however you can limit your report to just the summary by activating this option in the report generation form. Member end A or end B For member end forces and moments, if you wish to limit your envelope to the maximums and minimums that occur at just one particular member end (rather than from either end), you should tick "Member End A" and/or "Member End B". If you tick "Either Member End" (the default setting) then the maximums and minimums will be taken from either end. The enveloping tool is a fast and convenient way of determining the critical load cases, nodes, members and plates, regardless of the size of the job. Report member forces and moments in principal axes Member forces and moments are by default reported in the local axis system of the member, however for members with a non-zero principal angle you can get their principal forces and moments by ticking this option. Include warnings This check box allows you to suppress warning messages relating to the analysis results which sometimes appear in output reports. For example, if a non-linear analysis does not reach the requested convergence in some load cases, then warning messages are posted in the output report for those load cases. Intermediate stations SPACE GASS can print the displacements, forces and moments at any intermediate points along a member (not just at the end nodes). Before intermediate member displacements, forces and moments can be printed, you must specify how many equally spaced intermediate member stations are to be considered. The program automatically adds an extra station at each end of the member and at each point of application of a concentrated member load.

707

SPACE GASS 12 User Manual Sorting options Analysis results output can be sorted in one or both of two ways. 1. If sorted in order of load case, the report lists the data for every node (or member) under a main load case heading. This is repeated for each load case.

2. If sorted in order of node/member, the report lists the data for every load case under a main node (or member) heading. This is repeated for each node (or member). Member symbols notation Steel member design reports allow you to optionally include a summary sheet of the symbols used in the report together with a brief description of each. Member section properties This allows you to specify whether or not full section properties for the designed or checked members are included in the output. This option is usually suppressed because it enlarges the size of the report. Non-critical load cases The majority of the report for a steel member design gives information about the governing failure mode and the critical load case. A summary showing the performance of all of the other load cases can also be included if required. The non-critical load cases summary includes the load factor and the failure mode for each load case.

A description of the failure mode for each load case does not necessarily indicate that failure has occurred. It simply indicates the failure mode if the loads were increased enough to cause failure. Connection symbols notation Steel connection design reports allow you to optionally include a summary sheet of the symbols used in the report together with a brief description of each. Connection specifications This allows you to include or suppress the list of detailed specifications for the bolts, plates, welds, stiffeners and cleats from the detailed output reports. Connection calculations This setting allows you to include or suppress the loads, stresses, capacities, factors and other calculated values from the detailed output reports. Warnings and notes This check box allows you to suppress warning messages and notes relating to the design results which sometimes appear in output reports. Pass/fail criteria For output of steel member and connection design results you can set the "Pass/fail criteria" value to include only the members/connections which have passed, only the ones which have failed, or all members/connections. After completing the fields in the above form, you can click the Ok (if viewing), Print, Print preview or Page setup buttons.

708

Output

Page setup You can access the page setup form by selecting "Page Setup" from the File menu or clicking the "Page Setup" button on the "Print Text Report" or "Print Graphics" forms. The page setup form gives you full control over the printer selection, paper size, orientation, margins, layout, scales and output format for both text and graphics. There are separate tabs for text and graphics settings, however if the "Keep text and graphics common items the same" check box is selected then items that are common to both text and graphics only need to be changed in one tab rather than both.

If you want the text and graphics settings to be different then you must de-select the "Keep text and graphics common items the same" check box before making the changes. If you want to include your own logo in printed output, you should create a logo image file in JPG format, install it with the SPACE GASS utility tool, and then select either of the "Logo on first page only" or "Logo all pages" check boxes in the page setup form below. For best results, make the image file large enough so that it contains enough pixels for a printer resolution of 300 dpi or more. For example, if your printer operates at 600 dpi and you want the printed logo height to be 20mm, your logo image file will need to be at least 472 pixels in height (ie. 600/25.4x20). Regardless of the size of your logo image file, it will be scaled to print at the exact height you specify in the page setup form.

709


710

Output

711


View text report You can view a text report by clicking the toolbar button and then selecting "View Text Report" from the floating menu, or selecting "View Text Report" from the Output menu. You must first select the data that you want to view, after which the report viewer is displayed as follows.

The report viewer allows you to view any of the input or output data in an easy-to-read format. The side menu lets you go directly to any part of the report or hide any sections of the report before printing via the button located just above the side menu.

712

Output

Print preview You can generate a print preview by clicking the "Print Preview" button in the "View Text Report", "Print Text Report" or "Print Graphics" forms. The print preview allows you to see exactly how the output will appear on your printer. For text reports, the side menu lets you go directly to any part of the report or hide any sections of the report before printing. You can output direct to the printer or you can output to a text, PDF, HTML or picture file.

713


714

Output

Print text report You can print a text report by clicking the toolbar button and then selecting "Print Text Report" from the floating menu, or selecting "Print Text Report" from the Output menu. You must first select the data that you want to print, after which the print is produced.

715


Print graphics You can print graphics by clicking the toolbar button and then selecting "Print Graphics" from the floating menu, or selecting "Print Graphics" from the Output menu.

Scale Specify the desired hardcopy scale or leave it at zero for automatic scale to fit. For example, type in a value of 100 for a 1:100 scale. Title This is simply a description which you can use to describe the particular view that is being printed. It is placed near the bottom-left corner of the hardcopy and can be left blank if it is not required.

After completing the fields in the above form, you can click the Print, Print preview or Page setup buttons.

716

Output

The status report A status report showing the actual problem size and the problem size limits can be included at the start of each output report. It shows the number of nodes, members, restraints, sections, materials, constraints, loads, load cases and members with design data. It also shows the static and dynamic analysis status, ill-conditioning status, non-linear convergence, frontwidth, total degrees of freedom, whether there has been a steel or concrete design or check and the design code used. The status report can be suppressed if it is not required.

717

Standard Libraries Standard libraries SPACE GASS is supplied with libraries of standard sections, materials, bolts, plates, welds, spectral curves, reinforcing bars and moving load vehicles. The libraries can be accessed by SPACE GASS for rapid and convenient input of standard properties. They are also scanned frequently during analysis and design operations. You can get access to the libraries and retrieve data via the built-in library editor by clicking the button at various locations throughout SPACE GASS. You can also access the library editor by choosing "Edit Libraries" from the File menu. The library editor is shown below.

You cannot modify any of the standard libraries supplied with SPACE GASS, however you can create your own custom libraries and edit them without restriction. You can also copy

719

SPACE GASS 12 User Manual data from the standard libraries into your custom libraries. For more information, refer to The library editor.

720

Standard Libraries

The library editor You can open the library editor from the File menu or by clicking the button from various places within SPACE GASS. If opened from the File menu, the library editor gives you access to all types of library data (eg. sections, materials, bolts, plates, welds, reinforcing bars, spectral curves and moving load vehicles). If opened via the button from an area of SPACE GASS that is working with a specific type of data (eg. section property data), the library editor gives you access only to the applicable library types (eg. section property libraries).

Custom libraries You cannot edit or delete standard libraries (shown black in the library tree), however you can create and edit your own custom libraries (shown blue in the library tree). To create a custom library, click the appropriate library type in the library tree (eg. Section Libraries) and then click the "Add Library" button at the bottom of the library editor. Alternatively, you can rightclick on "Section Libraries" in the tree and then select "New Library".

721


Similarly, for section libraries you can add groups (sub-categories) by clicking the "Add Group" button at the bottom or by right-clicking on the custom library name and then selecting "New Group".

Once a custom library has been created, you can add data by clicking the appropriate "Add" button at the bottom or by right-clicking on the custom library, selecting the appropriate "New" item and then entering the required data. For section libraries, new sections can be added via the shape builder which automatically opens when you click the "Add Section" button. Sections can also be edited by clicking the shape builder button corner of the library editor.

near the top-right

You can also drag library items from a standard or custom library into a custom library. For section libraries, you can even drag a whole group into a custom library. If you hold down the Ctrl key while dragging then the items will be copied rather than being moved.

For information on how to import or export library data in other formats, refer to Importing and exporting. For information on how to import SPACE GASS 10 or older libraries, refer to Importing old libraries.

722

Standard Libraries

Importing and exporting Data can be imported into custom libraries or exported from standard or custom libraries by opening the library editor, right-clicking on the desired library in the library editor tree and then selecting the appropriate Import or Export option. If you wish to create a custom library by importing data from another source, it must be in a text or MS-Excel file formatted correctly for SPACE GASS. If you are not sure what the correct format is, you should export one of the standard SPACE GASS libraries to a file and then open the file to see how it is formatted and then use that as a pattern for the file you wish to import. For information on how to import SPACE GASS 10 or older libraries, refer to Importing old libraries.

723


Importing old libraries If you have custom libraries in SPACE GASS 10 or earlier formats, you can import them into the current version of SPACE GASS by opening the library editor, right-clicking on the desired library type in the library editor tree, selecting Import -> From Library and then locating and selecting the library to be imported. Note that SPACE GASS 10 custom libraries are always called SGCustomLib.MDB (or SGMoveC.dat for moving load vehicles) and are usually located in the SPACE GASS 10 program folder (c:\Program files (x86)\SPACE GASS\Exe or c:\Program files\SPACE GASS\Exe).

724

Standard Libraries

Section libraries Section libraries contain the geometric and strength information for the sections they contain. This includes the section name, shape type, section properties, dimensions, fabrication type and material strengths. Section libraries are now capable of holding non-standard sections and sections built from up to 10 shapes. When importing section data from another source into a SPACE GASS section library, if you are not sure what the correct format is, you should export one of the standard SPACE GASS libraries to a file and then open the file to see how it is formatted and then use that as a pattern for the file you wish to import. Note the following requirements for section property data. 1. For sections that have webs or flanges, the y-axis is parallel to the web(s) and the zaxis is parallel to the flange(s). For other sections the y-axis is the vertical axis and the z-axis is the horizontal axis. The y and z axes generally correspond to the minor and major axes respectively, however this is not always the case. 2. Moments of inertia and plastic section modulii are for the principal axes. 3. The principal angle is positive when the principal axes are rotated anti-clockwise with respect to the non-principal axes when looking at the cross section from a member's node A end towards its node B end. Note that the sign of the principal angle is shown reversed in the shape builder. 4. The centroid dimensions are the distances from the shape's reference point to the centroid along the y and z axes. Reference points are shown as a red dot in the image for each shape type in the Shape builder. 5. For column Tee sections, the dimensions are orientated the same as for beam Tee sections (ie. the depth is parallel to the web) even though column Tees are rotated through 90 degrees compared to beam Tees when used in a SPACE GASS model. 6. The "Section type" field must conform to one of the following: Circular Bar Square Bar Rectangular Bar Circular Tube Square Tube Rectangular Tube I or H Section Plate Web Girder Channel Beam Tee Column Tee Equal Angle Unequal Angle Cruciform Box Girder Wedge Slice Fillet Points Shape 725

SPACE GASS 12 User Manual LiteSteel Beam LSB Back-to-Back Lines Shape Triangle Cee Shape Zed Shape Top Hat Double Angled Short Double Angled Long Double Angled Starred Polygon Polygon Tube Equilateral Triangle Schifflerized Angle

726

Standard Libraries

Material libraries Each material in a standard material library contains the following information. 1. Young’s modulus 2. Poisson’s ratio 3. Mass density 4. Thermal coefficient 5. Concrete strength

727


Bolt libraries Each bolt in a standard bolt library contains the following information. 1. Diameter 2. Tensile strength (normal strength) 3. Tensile strength (high strength) 4. Tensile stress area - Cross-sectional area for calculating tensile stress 5. Shank area - Plain shank cross-sectional area 6. Core area - Core cross-sectional area 7. Minimum tension - Minimum bolt tension at installation

728

Standard Libraries

Plate libraries Each plate in a standard plate library contains the following information. 1. Width 2. Thickness 3. Yield stress (normal strength) 4. Tensile strength (normal strength) 5. Yield stress (high strength) 6. Tensile strength (high strength)

729


Weld libraries Each weld in a standard weld library contains the following information. 1. Size 2. Tensile strength (normal strength) 3. Tensile strength (high strength)

730

Standard Libraries

Reinforcing bar libraries Each bar in a standard reinforcing bar library contains the following information. 1. Diameter 2. Yield strength 3. Area

731


Spectral curve libraries Each curve in a standard spectral curve library contains the following information. 1. Damping factor (%) 2. Period, acceleration point pairs

732

Standard Libraries

Vehicle libraries Each vehicle in a standard vehicle library contains the following information. 1. Vehicle name 2. X, Y and load data for each wheel, where X is the distance back from the front of the vehicle to the wheel, and Y is the distance sideways from the centerline of the vehicle to the wheel.

733

Portal Frame Analysis Portal frame analysis This worked example considers the analysis of a typical 25m span haunched portal frame. Linear (1st order), non-linear (2nd order), dynamic (frequency and response) and buckling analyses have been performed and the results are presented in the computer printout at the end of this appendix. This appendix considers only the analysis of the portal frame. The portal frame member and connection design is covered in Portal frame member design and Portal frame connection design. This example is loosely based on the design example used in the AISC publication by Woolcock, Kitipornchai and Bradford (9). There are, however a number of significant differences between this example and the AISC example which can be summarized as follows. 



  

Because SPACE GASS has facilities for projected length member loads, the live load has been input over the plan rafter length rather than its inclined length. This was a situation that the software used in the AISC example could not model. Because SPACE GASS has facilities for automatically calculating haunch section properties based on the rafter size and the size of the member from which the haunch was cut, the haunch section properties are different. The AISC example simply approximates the haunch to a 530UB82 for half of its length and a 410UB60 for the other half. SPACE GASS uses a value for gravitational acceleration of 9.8066, the AISC example uses 9.82. SPACE GASS uses grade 300 steel, whereas the AISC example uses grade 250 steel. The purlins used in the AISC design example are assumed to be spaced at a maximum of 1500mm, while the structural drawings elsewhere in the publication show them to be spaced at 1200mm maximum. This SPACE GASS example uses purlin spacings of 1200mm as they are shown in the drawings.

Because the members in the AISC example have been designed by hand, they have not been able to take full advantage of some of the more calculation intensive and slightly more efficient higher tiers offered by the SPACE GASS steel member design module.

The differences between this example and the AISC example prohibit the direct comparison of results. However, if you wish to do so, you should first modify the SPACE GASS example in accordance with the differences listed above. If you do the modifications, you will find that the results of the two examples agree almost exactly.

735


Geometry and loads The portal frame considered in this example has the following basic properties. Building length: Portal span: Portal spacing: Eave height: Apex height: Columns: Rafters: Haunches: Roof and walls: Static load data Dead load (DL):

72m 25m 9m 7.5m 8.155m (3 roof pitch) 530 UB 92.4 360 UB 50.7 360 UB 50.7 (3m long) Trimdek 0.47 sheeting

Sheeting and purlins 0.90kN/m (slope) Self weight (calculated by SPACE GASS)

Live load (LL):

2.25kN/m (plan) 4.5kN concentrated at apex

Cross wind (CW): (external)

6.30kN/m on windward columns 4.50kN/m on leeward columns 6.48kN/m uplift on windward 8m of rafter 3.60kN/m uplift on central 8m of rafter 2.16kN/m uplift on leeward remainder of rafter

Longit. wind (LW1): (1st internal frame)

4.14kN/m outward on columns 5.04kN/m uplift on rafters

Longit. wind (LW2): (external suction)


Cross wind (IPCW): (Internal pressure)


Longit. wind (IPLW): (Internal pressure)


Load combination 1: Load combination 2: Load combination 3: Load combination 4: Load combination 5:

1.25DL + 1.50LL 0.80DL + CW + IPCW 1.25DL + CW - 0.96IPCW (ISCW) 0.80DL + LW1 + IPLW 1.25DL + LW2 - 6.50IPLW (ISLW)

The distributed live load is based on a roof area of 9m x 25m = 225sqm which requires a distributed live load of 0.25kPa. The wind loads are based on terrain category 3 (industrial area) for region B with Vu = 60m/s and Vs = 38m/s. Taking into account the height of the rafters and purlins (200mm), the eaves height is assumed to be 8m and the apex height is assumed to be 8.7m.

736

Portal Frame Analysis

Dynamic frequency mass data Dead load (DL): Self mass (calculated by SPACE GASS) Sheeting and purlins 91.77kg/m (slope) Live load (LL):

229.43kg/m (plan) 458.86kg concentrated at apex

Total distributed mass: 91.77 + 229.43 = 321.20kg/m Mass at nodes 3 and 11: 1.63/2.0*321.20 = 0.26 tonne Mass at nodes 4 and 10: 1.63*321.20 = 0.52 tonne Mass at nodes 5 and 9: (1.63/2.0+2.99/2.0)*321.20 = 0.74 tonne Mass at nodes 6 and 8: (2.99/2.0+6.26/2.0)*321.20 = 1.49 tonne Mass at node 7: 6.26*321.20+458.86 = 2.47 tonne Dynamic response data Spectral curve: Damping: Dynamic modes: Direction vector: Loading code: Vertical direction: Sign of the results: Base shear: Site factor: Acceleration factor: Importance factor: Structural response factor: Spectral curve multiplier: Mode combination method:

1989 Newcastle earthquake, magnitude 6.5 5% 1,2 and 3 Dx=1.0, Dy=0.0, Dz=0.0 General Y-axis Signed to match first dynamic mode Not less than 80% of total static force 2.0 0.08 1.0 4.5 0.017778 SRSS

Load combinations The static load combinations are in accordance with typical strength limit state stipulations (excluding earthquake loading) as follows. 1. 2. 3. 4.

1.25G + 1.5Q 1.25G + Wu 0.80G + 1.5Q 0.80G + Wu

While these load combinations are no longer in line with AS1170, they have been retained for compatibility with the AISC publication on which this example is based.

In this worked example it has been assumed that the distributed live load in load case 2 need not be considered to act simultaneously with any wind load. The structure will be designed to support either the distributed live load or the wind load, whichever produces the most critical effect. Notes on the structure Extra nodes have been positioned at mid-height of the columns and at midspan of the rafters. This is not absolutely necessary but it means that graphical displays will automatically show

737

SPACE GASS 12 User Manual the values of forces and moments at these points. Of course you can obtain the deflections, forces and moments at these points without having to have nodes there by simply scaling them off the diagrams or by obtaining an intermediate displacements, forces and moments report, however these methods may sometimes be less convenient than having the values displayed graphically. Nodes have also been positioned at the mid-points and end-points of the haunches. These are necessary so that the section properties can be varied along the haunch. In the above example, the haunch has been modelled as a tapered 360 UB 50. Only two prismatic members were used to approximate the tapered haunch because tests have shown that this gives results very close to the exact solution. If you wish to experiment with this, try inputting some frames with varying numbers of haunch segments, and compare the results of the deflections and bending moments. In fact, haunches do not have much effect at all on the bending moments in other parts of the frame, however they do eliminate the need to design the rafters for the high bending moments which usually occur at the knee. Haunches can also offer significant reductions in deflection of the frame. The frame, as modelled in SPACE GASS, is shown in the following diagrams.

Basic arrangement of nodes and members

738


Frame elevation

739


Method of input The portal frame in this example was initially input as a single bay portal frame using the structure wizard. This allowed quick and easy generation of the basic structural geometry, restraints, section properties (including the haunch section properties) and material properties. If the extra column and rafter nodes were not required, it would then have been a simple matter to add the loads (graphically or using datasheet input) and then perform the analysis. Node, member and plate numbering In this example we wanted to match the node, member and plate numbering with the numbering used in the AISC example. Therefore, it was necessary to modify the geometry slightly so that the extra nodes were added and the nodes and members were re-numbered. This was done graphically by simply subdividing the members and then renumbering the structure with the extra nodes included. The rafter and haunch section properties were assigned to members 3 - 10 by graphically changing the section property numbers of members 5, 6, 7 and 8 to section 2, members 3 and 10 to section 3, and members 4 and 9 to section 4. Node restraints When the structural geometry was established, node restraints of FFFRFR were applied to support nodes 1 and 13, and restraints of RRFRRR were applied to rafter nodes 3, 6, 7, 8 and 11. The restraints on nodes 1 and 13 specified that the structure was pin-based, allowing rotation about both the X and Z axes. The standard 2D frame pin restraint of FFFFFR was not used in this case because it would have prevented rotation about the X-axis. The rafter node restraints were applied to simulate the effect of wall and roof bracing that would prevent any out-of-plane (Z-axis) movements at those nodes. A general restraint of RRFRRR was not used in this case because it would have prevented the out-of-plane movements of nodes 2, 4, 5, 9, 10 and 12 which, in real life, would be free to move in that direction. Although no out-of-plane movements would occur in a static analysis (due to no loads in that direction), they could occur in a buckling analysis and, if restrained, could result in incorrect buckling load factors and effective lengths. If no intermediate nodes were present that could move in the out-of-plane directions then a general restraint could have been used.

Under normal circumstances it would not have been necessary to match the node and member numbering with the AISC example. This would have removed the necessity to subdivide the members, or change the member properties and node restraints as described above. Loads The node and member loads were applied graphically. Although there are many member loads, the graphical input facility made it very easy to input them en-masse. For most load cases, it was simply a matter of placing a window around the members and then specifying the load applied to them. Self weight, combination load cases and load case titles were input using datasheets. Input check As a final check before the analysis was initiated, loading diagrams for each load case were viewed followed by an output report of the complete structural data. Any errors in the data were corrected and the model was then ready for analysis.

740


Analysis procedure Linear analysis The first analysis to be performed was a linear analysis for the primary load cases 1 - 7. The results of this analysis were used to check frame deflections. Non-linear analysis Load cases 10 - 14 were analysed in a second run because the steel member design example is based on factored combination load cases analysed non-linearly. Both P- and P- effects were activated, while axial shortening wasn’t. The linear analysis results for the primary load cases were retained and the stiffness matrix was written to the disk.

A general optimization method was used, however this had little impact on the analysis time due to the small size of the model. Dynamic frequency analysis The self mass of the portal frame was considered in association with mass load case 8 (which incorporated the lumped masses due to both dead and live loading conditions). Six mode shapes were requested. Dynamic spectral response analysis The dynamic spectral response analysis was performed for spectral load case 9. The sign of the results was determined automatically and all results were retained for those load cases analysed linearly or non-linearly. Buckling analysis The default options were selected for the buckling analysis (ie. only one mode shape was calculated).

741


Analysis results The following summary was developed based upon the results: Maximum sway deflection: Maximum vertical deflection: Maximum moment (column - knee): Maximum moment (rafter - haunch): Maximum moment (apex): Minimum frame buckling load factor: Natural frequencies (first 6 frequencies):

99mm (load case 3) 119mm (load case 4) 527kNm (load case 11) 211kNm (load case 11) 127kNm (load case 11) 8.23 (load case 14) 0.86, 1.82, 4.88, 6.27, 6.28, 6.76 Hz

The dynamic response spectrum analysis resulted in small displacements, forces and moments that were insignificant in comparison with the static load cases. The results of the non-linear analysis were then used to perform a steel member check and a steel connection design. As an interesting exercise, the results of the non-linear analysis were then compared with the results of a linear analysis of the combination load cases. Load case 11 was still found to be critical with the new moments being 542kNm at the knee, 223kNm at the end of the haunch and 132kNm at the apex. You can see that the linear moments are actually greater than the non-linear moments. This is also shown in the AISC example.

742


Graphical output The following diagrams are examples of the graphical output that can be obtained from SPACE GASS on the screen or printer.

Basic arrangement of nodes and members

Loading diagram (load case 3)

Deflection diagram (load cases 2, 3 and 4)

743


Bending moment diagram (load case 10)



744




Bending moment diagram envelope (load cases 10-14)

745


Dynamic mode shape (load case 8)

Buckling mode shape (load case 12) – Note the out-of-plane buckling mode

746


Analysis input report This report extract shows all of the frame analysis input data, including lumped masses and spectral load cases. ANALYSIS STATUS REPORT ---------------------Job name ...... Portal Frame Worked Example Location ...... C:\Trunk\Shipping\Samples\Mixed This is a 2D portal frame analysed and designed example appendices. Length units ......................... m Section property units ............... mm Material strength units .............. MPa Mass density units ................... kg/m^3 Temperature units .................... Celsius Force units .......................... kN Moment units ......................... kNm Mass units ........................... kg Acceleration units ................... g's Translation units .................... mm Stress units ......................... MPa Nodes ................................ 13 Members .............................. 12 Plates ............................... 0 Restrained nodes ..................... 7 Nodes with spring restraints ......... 0 Section properties ................... 4 Material properties .................. 1 Constrained nodes .................... 0 Member offsets ....................... 4 Node loads ........................... 1 Prescribed node displacements ........ 0 Member concentrated loads ............ 0 Member distributed forces ............ 78 Member distributed torsions .......... 0 Thermal loads ........................ 0 Member prestress loads ............... 0 Plate pressure loads ................. 0 Self weight load cases ............... 2 Combination load cases ............... 5 Load cases with titles ............... 14 Lumped masses ........................ 18 Spectral load cases .................. 1 Static analysis ...................... Y Dynamic analysis ..................... N Response analysis .................... N Buckling analysis .................... Y Ill-conditioned ...................... N Non-linear convergence ............... Y Frontwidth ........................... 12 Total degrees of freedom ............. 65 Static load cases .................... 8 Mass load cases ...................... 2

for the SPACE GASS worked

( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( (

32765) 32765) 32765) 32765) 32765) 5000) 999) 32765) 32765) 250000) 250000) 250000) 250000) 250000) 250000) 250000) 250000) 10000) 10000) 10000) 250000) 10000)

( (

10000) 10000)

747

SPACE GASS 12 User Manual STEEL DESIGN STATUS REPORT -------------------------Members with design data ............. Member design or check ............... Connections with design data ......... Connection design .................... NODE COORDINATES (m) ---------------X Node Coord 1 0.000 2 0.000 3 0.000 4 1.630 5 3.260 6 6.250 7 12.500 8 18.750 9 21.740 10 23.370 11 25.000 12 25.000 13 25.000

Y Coord 0.000 3.750 7.500 7.585 7.671 7.828 8.155 7.828 7.671 7.585 7.500 3.750 0.000

4 C 5 Y

( 32765) AS4100 ( 32765) AS4100

Z Coord 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

MEMBER DATA (deg,kNm/rad,m) ----------- (F=Fixed, R=Released) (*=Cable length) Dir Dir Dir Memb Memb Angle Node Axis Type Node A Node B Sect Mat 1 0.00 Norm 1 2 1 1 2 0.00 Norm 2 3 1 1 3 0.00 Norm 3 4 3 1 4 0.00 Norm 4 5 4 1 5 0.00 Norm 5 6 2 1 6 0.00 Norm 6 7 2 1 7 0.00 Norm 7 8 2 1 8 0.00 Norm 8 9 2 1 9 0.00 Norm 9 10 4 1 10 0.00 Norm 10 11 3 1 11 0.00 Norm 11 12 1 1 12 0.00 Norm 12 13 1 1

Node A Fixity FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF

Node B Fixity FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF

Length 3.750 3.750 1.632 1.632 2.994 6.259 6.259 2.994 1.632 1.632 3.750 3.750

NODE RESTRAINTS (kN/m,kNm/rad) --------------- (F=Fixed, R=Released, S=Spring, *=General) Rest X Axial Y Axial Z Axial X Rotation Y Rotation Z Rotati Node Code Stiffness Stiffness Stiffness Stiffness Stiffness Stiffne 1 FFFRFR 3 RRFRRR 6 RRFRRR 7 RRFRRR 8 RRFRRR 11 RRFRRR

748

Portal Frame Analysis 13 FFFRFR SECTION PROPERTIES (mm,mm^2,mm^4,deg) -----------------Sect Name 1 530 UB 92.4 2 360 UB 50.7 3 360 UB 50.7-A 4 360 UB 50.7-B

Y-Axis Mom of In 2.3800E+07 9.6000E+06 1.4404E+07 1.4399E+07

Shape Source I shape Aust300 I shape Aust300 Multiple shapes User Multiple shapes User

Sect 1 2 3 4

Area of Section 1.1800E+04 6.4700E+03 1.0845E+04 9.7132E+03

Sect 1

Shape I shape

Trans Mir Rotate No No 0.00

D 533.00

2

I shape

No

No

0.00

356.00

3

I shape

No

No

0.00

356.00

Beam Tee

No

No

180.00

333.10

I shape

No

No

0.00

356.00

Beam Tee

No

No

4

Torsion Constant 7.7500E+05 2.4100E+05 3.4719E+05 3.2708E+05

Mark C1 R1 S3 S4

Z-Axis Mom of In 5.5400E+08 1.4200E+08 6.4354E+08 3.6751E+08

180.00 178.002

Y-Axis Shr Area Infinite Infinite Infinite Infinite

Bt/Bb Btw/Bbw 209.00 0.00 209.00 0.00 171.00 0.00 171.00 0.00 171.00 0.00 171.00 0.00 171.00 0.00 0.00 0.00 171.00 0.00 171.00 0.00 171.00 0.00 0.00 0.00

MATERIAL PROPERTIES (MPa,kg/m^3,strain/degC) ------------------Young's Poisson's Mass Matl Material Name Modulus Ratio Density 1 STEEL 2.0000E+05 0.25 7.8500E+03 MEMBER OFFSETS (m) -------------Memb Axes Dxa 3 L 0.000 4 L 0.000 9 L 0.000 10 L 0.000 NODE LOADS (kN,kNm) ---------Load X-Axis Case Node Force 2 7 0.000

Dya -0.168 -0.106 -0.106 -0.168

Y-Axis Force -4.500

Z-Axis Shr Area Infinite Infinite Infinite Infinite

Dza 0.000 0.000 0.000 0.000

Dxb 0.000 0.000 0.000 0.000

Z-Axis Force 0.000

X-Axis Moment 0.000

Tt/Tb 15.60 15.60 11.50 11.50 11.50 11.50 11.50 0.00 11.50 11.50 11.50 0.00

Pri Ang 0. 0. 0. 0.

Tw/ 10. 14. 7. 11. 7. 11. 7. 11. 7. 11. 7. 11.

Coeff of Expansion 1.170E-05

Concrete Strength

Dyb -0.168 -0.106 -0.106 -0.168

Dzb 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000

749

Z-Axis Moment 0.000


MEMBER DISTRIBUTED FORCES (m,kN/m) ------------------------Load Sub Axes Start Case Memb Load Sys Position 1 3 1 GI 0.000%

2

3

750

Finish Position 100.000%

4

1

GI

0.000%

100.000%

5

1

GI

0.000%

100.000%

6

1

GI

0.000%

100.000%

7

1

GI

0.000%

100.000%

8

1

GI

0.000%

100.000%

9

1

GI

0.000%

100.000%

10

1

GI

0.000%

100.000%

3

1

GP

0.000%

100.000%

4

1

GP

0.000%

100.000%

5

1

GP

0.000%

100.000%

6

1

GP

0.000%

100.000%

7

1

GP

0.000%

100.000%

8

1

GP

0.000%

100.000%

9

1

GP

0.000%

100.000%

10

1

GP

0.000%

100.000%

1

1

GP

0.000%

100.000%

2

1

GP

0.000%

100.000%

3

1

L

0.000%

100.000%

4

1

L

0.000%

100.000%

5

1

L

0.000%

100.000%

6

1

L

0.000

1.741

6

2

L

1.741

6.259

7

1

L

0.000

3.482

7

2

L

3.482

6.259

X Start/ Finish 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 6.300 6.300 6.300 6.300 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y Start/ Finish -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -0.900 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 -2.250 0.000 0.000 0.000 0.000 6.480 6.480 6.480 6.480 6.480 6.480 6.480 6.480 3.600 3.600 3.600 3.600 2.160 2.160

Z Star Fini 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0


4

5

8

1

L

0.000%

100.000%

9

1

L

0.000%

100.000%

10

1

L

0.000%

100.000%

11

1

GP

0.000%

100.000%

12

1

GP

0.000%

100.000%

1

1

L

0.000%

100.000%

2

1

L

0.000%

100.000%

3

1

L

0.000%

100.000%

4

1

L

0.000%

100.000%

5

1

L

0.000%

100.000%

6

1

L

0.000%

100.000%

7

1

L

0.000%

100.000%

8

1

L

0.000%

100.000%

9

1

L

0.000%

100.000%

10

1

L

0.000%

100.000%

11

1

L

0.000%

100.000%

12

1

L

0.000%

100.000%

1

1

L

0.000%

100.000%

2

1

L

0.000%

100.000%

3

1

L

0.000%

100.000%

4

1

L

0.000%

100.000%

5

1

L

0.000%

100.000%

6

1

L

0.000%

100.000%

7

1

L

0.000%

100.000%

8

1

L

0.000%

100.000%

9

1

L

0.000%

100.000%

10

1

L

0.000%

100.000%

11

1

L

0.000%

100.000%

0.000 0.000 0.000 0.000 0.000 0.000 4.500 4.500 4.500 4.500 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

2.160 2.160 2.160 2.160 2.160 2.160 0.000 0.000 0.000 0.000 4.140 4.140 4.140 4.140 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 5.040 4.140 4.140 4.140 4.140 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440 1.440

751

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0


6

7

12

1

L

0.000%

100.000%

1

1

L

0.000%

100.000%

2

1

L

0.000%

100.000%

3

1

L

0.000%

100.000%

4

1

L

0.000%

100.000%

5

1

L

0.000%

100.000%

6

1

L

0.000%

100.000%

7

1

L

0.000%

100.000%

8

1

L

0.000%

100.000%

9

1

L

0.000%

100.000%

10

1

L

0.000%

100.000%

11

1

L

0.000%

100.000%

12

1

L

0.000%

100.000%

1

1

L

0.000%

100.000%

2

1

L

0.000%

100.000%

3

1

L

0.000%

100.000%

4

1

L

0.000%

100.000%

5

1

L

0.000%

100.000%

6

1

L

0.000%

100.000%

7

1

L

0.000%

100.000%

8

1

L

0.000%

100.000%

9

1

L

0.000%

100.000%

10

1

L

0.000%

100.000%

11

1

L

0.000%

100.000%

12

1

L

0.000%

100.000%

SELF WEIGHT (g's) ----------Load X-Axis

752

Y-Axis

Z-Axis

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.440 1.440 1.440 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 4.680 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900 0.900

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Portal Frame Analysis Case 1 8

Accel'n 0.000 0.000

Accel'n -1.000 -1.000

Accel'n 0.000 0.000

COMBINATION LOAD CASES ---------------------Load case 10: 1.25DL+1.5LL 1.250 * Load case 1: Dead load (DL) 1.500 * Load case 2: Live load including 4.5kN at ridge (LL) Load case 11: 0.8DL+CW+IPCW 0.800 * Load case 1: Dead load (DL) 1.000 * Load case 3: Cross wind (CW) 1.000 * Load case 6: Cross wind internal pressure (IPCW) Load case 12: 1.25DL+CW+ISCW 1.250 * Load case 1: Dead load (DL) 1.000 * Load case 3: Cross wind (CW) -0.960 * Load case 6: Cross wind internal pressure (IPCW) Load case 13: 0.8DL+LW1+IPLW 0.800 * Load case 1: Dead load (DL) 1.000 * Load case 4: Longitudinal wind at first internal frame (LW1) 1.000 * Load case 7: Longitudinal wind internal pressure (IPLW) Load case 14: 1.25DL+LW2+ISLW 1.250 * Load case 1: Dead load (DL) 1.000 * Load case 5: Longitudinal wind with 0.2 external suction (LW2) -6.500 * Load case 7: Longitudinal wind internal pressure (IPLW) LOAD CASE TITLES ---------------Load Case Title 1 Dead load (DL) 2 Live load including 4.5kN at ridge (LL) 3 Cross wind (CW) 4 Longitudinal wind at first internal frame (LW1) 5 Longitudinal wind with 0.2 external suction (LW2) 6 Cross wind internal pressure (IPCW) 7 Longitudinal wind internal pressure (IPLW) 8 Lumped masses (DL+LL) 9 Spectral load case 10 1.25DL+1.5LL 11 0.8DL+CW+IPCW 12 1.25DL+CW+ISCW 13 0.8DL+LW1+IPLW 14 1.25DL+LW2+ISLW LUMPED MASSES (kg,kgm^2) ------------Load X-Axis

Y-Axis

Z-Axis

X-Axis

Y-Axis

753

Z-Axis

SPACE GASS 12 User Manual Case 8

Node 3 4 5 6 7 8 9 10 11

Mass 260.000 520.000 740.000 1490.000 2470.000 1490.000 740.000 520.000 260.000

Mass 260.000 520.000 740.000 1490.000 2470.000 1490.000 740.000 520.000 260.000

Mass 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Mass 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Mass 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

SPECTRAL LOAD DATA -----------------Load Mode Damping Mass Direction Vector Case Shape Spectral Curve Factor Case Dx Dy Dz 9 1 NEWCASTLE 5% 5.0% 8 1.000 0.000 0.000 2 NEWCASTLE 5% 5.0% 8 1.000 0.000 0.000 3 NEWCASTLE 5% 5.0% 8 1.000 0.000 0.000 Damping Spectral Curve Factor Description NEWCASTLE 5% 5.0% Newcastle 1989, Dir=N-S, Mag=6.5

754

Mass 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000


Static analysis report (itemised) This report extract shows the node displacements for primary load cases (1-9), the member forces and moments for combination load cases (10-14), and the node reactions for all load cases. Note that SPACE GASS lets you choose any desired load cases for each part of the report. Although load case 9 is a spectral load case rather than a static load case, it is also included in this part of the report because its results are in the same form as those of a static analysis. NODE DISPLACEMENTS (mm,rad) -----------------Load case 1 (Linear): Dead load (DL)

Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 -3.443 -1.988 -1.704 -1.392 -0.795 0.000 0.795 1.392 1.704 1.988 3.443 0.000

Y-Axis Transl'n 0.000 -0.037 -0.069 -3.152 -7.573 -19.423 -35.597 -19.423 -7.573 -3.152 -0.069 -0.037 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation 0.001 0.000 -0.001 -0.002 -0.003 -0.004 0.000 0.004 0.003 0.002 0.001 0.000 -0.001

Load case 2 (Linear): Live load including 4.5kN at ridge (LL)

Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 -6.194 -3.698 -3.193 -2.629 -1.532 0.000 1.532 2.629 3.193 3.698 6.194 0.000

Y-Axis Transl'n 0.000 -0.048 -0.097 -5.540 -13.435 -35.183 -66.190 -35.183 -13.435 -5.540 -0.097 -0.048 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation 0.002 0.001 -0.003 -0.004 -0.006 -0.008 0.000 0.008 0.006 0.004 0.003 -0.001 -0.002

Load case 3 (Linear): Cross wind (CW)

755


Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 63.213 99.246 98.835 98.245 96.822 93.373 92.581 90.748 89.618 88.460 43.844 0.000

Y-Axis Transl'n 0.000 0.117 0.234 -3.476 -0.524 27.786 96.251 78.638 42.540 21.016 0.084 0.042 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation -0.018 -0.014 -0.004 -0.001 0.004 0.013 0.005 -0.010 -0.013 -0.013 -0.013 -0.012 -0.012

Load case 4 (Linear): Longitudinal wind at first internal frame (LW1)

Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 10.251 6.504 5.584 4.560 2.597 0.000 -2.597 -4.560 -5.584 -6.504 -10.251 0.000

Y-Axis Transl'n 0.000 0.100 0.200 9.951 24.370 64.155 118.858 64.155 24.370 9.951 0.200 0.100 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation -0.003 -0.002 0.005 0.007 0.010 0.015 0.000 -0.015 -0.010 -0.007 -0.005 0.002 0.003

Load case 5 (Linear): Longitudinal wind with 0.2 external suction (LW2) Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 2.808 1.823 1.565 1.278 0.728 0.000 -0.728 -1.278 -1.565 -1.823 -2.808 0.000

Y-Axis Transl'n 0.000 0.029 0.057 2.772 6.813 18.027 33.464 18.027 6.813 2.772 0.057 0.029 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Load case 6 (Linear): Cross wind internal pressure (IPCW)

756

Z-Axis Rotation -0.001 0.000 0.001 0.002 0.003 0.004 0.000 -0.004 -0.003 -0.002 -0.001 0.000 0.001


Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 9.127 5.925 5.087 4.154 2.365 0.000 -2.365 -4.154 -5.087 -5.925 -9.127 0.000

Y-Axis Transl'n 0.000 0.093 0.186 9.010 22.143 58.586 108.759 58.586 22.143 9.010 0.186 0.093 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation -0.003 -0.001 0.004 0.007 0.009 0.013 0.000 -0.013 -0.009 -0.007 -0.004 0.001 0.003

Load case 7 (Linear): Longitudinal wind internal pressure (IPLW)

Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 1.755 1.139 0.978 0.799 0.455 0.000 -0.455 -0.799 -0.978 -1.139 -1.755 0.000

Y-Axis Transl'n 0.000 0.018 0.036 1.733 4.258 11.267 20.915 11.267 4.258 1.733 0.036 0.018 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation -0.001 0.000 0.001 0.001 0.002 0.003 0.000 -0.003 -0.002 -0.001 -0.001 0.000 0.001

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation 0.000 0.000 -0.001 -0.001 -0.001 -0.002 0.000 0.002 0.001 0.001 0.001 0.000 0.000

Load case 8 (Linear): Lumped masses (DL+LL)

Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 -1.257 -0.716 -0.613 -0.500 -0.285 0.000 0.285 0.500 0.613 0.716 1.257 0.000

Y-Axis Transl'n 0.000 -0.020 -0.034 -1.166 -2.777 -7.050 -12.848 -7.050 -2.777 -1.166 -0.034 -0.020 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

757


Load case 9 (Spectral) Spectral load case

Node 1 2 3 4 5 6 7 8 9 10 11 12 13

X-Axis Transl'n 0.000 0.142 0.255 0.257 0.258 0.258 0.254 0.258 0.258 0.257 0.255 0.142 0.000

Y-Axis Transl'n 0.000 0.000 0.001 -0.052 -0.105 -0.168 0.000 0.168 0.105 0.052 0.001 0.000 0.000

Z-Axis Transl'n 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Rotation 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

MEMBER FORCES AND MOMENTS (kN,kNm) ------------------------Load case 10 (Non-linear): 1.25DL+1.5LL Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.988% Cnv (Res gov) Memb 1 2 3 4 5 6 7 8 9 10 11 12

Node 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13

Axial Force 77.150 72.892 72.892 68.634 44.163 43.693 43.728 43.261 43.249 42.445 42.439 40.765 40.765 42.439 42.445 43.249 43.261 43.728 43.693 44.163 68.634 72.892 72.892 77.150

Y-Axis Shear -40.644 -40.644 -40.644 -40.644 66.421 57.393 57.365 48.514 48.523 33.220 33.230 1.242 -1.242 -33.230 -33.220 -48.523 -48.514 -57.365 -57.393 -66.421 40.644 40.644 40.644 40.644

Z-Axis Shear 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Load case 11 (Non-linear): 0.8DL+CW+IPCW

758

X-Axis Torsion 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 -153.483 -153.483 -305.488 -298.089 -196.504 -199.207 -112.024 -116.590 7.872 7.868 118.633 118.633 7.868 7.872 -116.590 -112.024 -199.207 -196.504 -298.089 -305.488 -153.483 -153.483 0.000

Portal Frame Analysis Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.987% Cnv (Res gov) Memb 1 2 3 4 5 6 7 8 9 10 11 12

Node 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13

Axial Force -111.210 -113.935 -113.935 -116.660 -71.579 -71.697 -71.756 -71.869 -71.849 -72.025 -72.015 -72.381 -71.867 -71.501 -71.507 -71.332 -71.344 -71.231 -71.195 -71.077 -70.823 -68.098 -68.098 -65.373

Y-Axis Shear 77.731 71.656 71.662 65.587 -113.084 -97.131 -97.084 -81.016 -81.028 -50.958 -50.973 -1.128 -8.690 32.142 32.122 49.258 49.241 58.257 58.302 67.204 -67.473 -33.048 -33.050 1.375

Z-Axis Shear 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Torsion 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment -0.001 272.886 272.885 526.758 514.769 343.477 347.913 203.508 211.094 17.416 17.423 -127.088 -127.088 -50.702 -50.708 66.786 59.254 144.881 140.473 241.074 252.982 61.589 61.588 0.000

Load case 12 (Non-linear): 1.25DL+CW+ISCW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.995% Cnv (Res gov) Memb 1 2 3 4 5 6 7 8 9 10 11

Node 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11

Axial Force 13.908 9.650 9.650 5.392 38.036 37.852 37.854 37.677 37.676 37.402 37.401 36.829 37.439 38.010 38.015 38.289 38.299 38.476 38.449 38.633 53.057

Y-Axis Shear 43.143 2.670 2.669 -37.804 3.417 3.126 3.103 2.989 2.998 3.723 3.728 -7.768 -3.883 -24.391 -24.384 -36.594 -36.583 -43.748 -43.771 -51.114 35.916

Z-Axis Shear 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Torsion 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

759

Z-Axis Moment 0.000 86.625 86.625 21.162 27.534 33.511 31.166 36.738 32.760 43.657 43.658 42.300 42.299 -41.230 -41.230 -133.038 -128.995 -194.408 -192.028 -269.109 -275.580


12

12 12 13

57.315 57.315 61.573

35.943 35.941 35.968

0.000 0.000 0.000

0.000 0.000 0.000

0.000 0.000 0.000

-138.467 -138.467 0.000

Load case 13 (Non-linear): 0.8DL+LW1+IPLW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.988% Cnv (Res gov) Memb 1 2 3 4 5 6 7 8 9 10 11 12

Node 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13

Axial Force -54.034 -56.759 -56.759 -59.484 -55.536 -55.654 -55.684 -55.797 -55.787 -55.962 -55.957 -56.323 -56.323 -55.957 -55.962 -55.787 -55.797 -55.684 -55.654 -55.536 -59.484 -56.759 -56.759 -54.034

Y-Axis Shear 14.709 33.609 33.609 52.509 -56.667 -49.234 -49.198 -41.651 -41.664 -27.223 -27.235 2.950 -2.950 27.235 27.223 41.664 41.651 49.198 49.234 56.667 -52.509 -33.609 -33.609 -14.709

Z-Axis Shear 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Torsion 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 90.108 90.108 251.759 242.455 156.521 159.966 86.556 92.446 -8.640 -8.637 -81.824 -81.824 -8.637 -8.640 92.446 86.556 159.966 156.521 242.455 251.759 90.108 90.108 0.000

Load case 14 (Non-linear): 1.25DL+LW2+ISLW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.983% Cnv (Res gov) Memb 1 2 3 4 5 6 7 8

760

Node 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9

Axial Force 86.713 82.455 82.455 78.197 65.332 65.148 65.187 65.010 64.996 64.722 64.715 64.144 64.144 64.715 64.722 64.996

Y-Axis Shear -28.268 -44.806 -44.806 -61.343 74.891 64.158 64.116 53.560 53.573 35.144 35.159 -3.363 3.363 -35.159 -35.144 -53.573

Z-Axis Shear 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Torsion 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 -138.160 -138.160 -336.781 -325.836 -211.544 -215.576 -118.343 -125.205 10.888 10.882 114.887 114.887 10.882 10.888 -125.205

Portal Frame Analysis 9 10 11 12

9 10 10 11 11 12 12 13

65.010 65.187 65.148 65.332 78.197 82.455 82.455 86.713

-53.560 -64.116 -64.158 -74.891 61.343 44.806 44.806 28.268

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

-118.343 -215.576 -211.544 -325.836 -336.781 -138.160 -138.160 0.000

NODE REACTIONS (kN,kNm) -------------Load case 1 (Linear): Dead load (DL)

Node 1 13

X-Axis Force 10.293 -10.293

Y-Axis Force 25.270 25.270

Z-Axis Force 0.000 0.000

X-Axis Moment 0.000 0.000

Y-Axis Moment 0.000 0.000

Z-Axis Moment 0.000 0.000

Load Reac

0.000 0.000

-50.540 50.540

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil Resid

4.477E-13 4.547E-13

0.000E+00 4.405E-13

0.000E+00 0.000E+00

0.000E+00

0.000E+00

4.334E-13

Load case 2 (Linear): Live load including 4.5kN at ridge (LL)

Node 1 13

X-Axis Force 18.261 -18.261

Y-Axis Force 30.375 30.375





Load Reac

0.000 0.000

-60.750 60.750

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil Resid

8.528E-13 1.116E-12

0.000E+00 3.411E-13

0.000E+00 0.000E+00

0.000E+00

0.000E+00

1.052E-12

Load case 3 (Linear): Cross wind (CW)

Node 1 13

X-Axis Force -70.889 -8.224

Y-Axis Force -73.554 -26.461





Load Reac

79.112 -79.112

100.014 -100.014

0.000 0.000

0.000 0.000

0.000 0.000

3.992 0.000

Equil Resid

0.000E+00 4.405E-11

0.000E+00 2.018E-12

0.000E+00 0.000E+00

0.000E+00

0.000E+00

3.865E-12

761

SPACE GASS 12 User Manual Load case 4 (Linear): Longitudinal wind at first internal frame (LW1) X-Axis Force -20.355 20.355 0.000 0.000

Y-Axis Force -63.000 -63.000 126.000 -126.000

Z-Axis Force 0.000 0.000 0.000 0.000

X-Axis Moment 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 0.000 0.000 0.000

Equil -1.478E-12 Resid 1.364E-12

0.000E+00 2.345E-13

0.000E+00 0.000E+00

0.000E+00

0.000E+00

9.948E-13

Node 1 13 Load Reac

Load case 5 (Linear): Longitudinal wind with 0.2 external suction (LW2) Node 1 13

X-Axis Force -4.820 4.820

Y-Axis Force -18.000 -18.000





Load Reac

0.000 0.000

36.000 -36.000

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil -4.370E-13 Resid 3.837E-13

0.000E+00 2.274E-13

0.000E+00 0.000E+00

0.000E+00

0.000E+00

3.695E-13

Load case 6 (Linear): Cross wind internal pressure (IPCW)

Node 1 13

X-Axis Force -15.667 15.667

Y-Axis Force -58.500 -58.500





Load Reac

0.000 0.000

117.000 -117.000

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil -1.393E-12 Resid 3.297E-12

0.000E+00 1.535E-12

0.000E+00 0.000E+00

0.000E+00

0.000E+00

1.080E-12

Load case 7 (Linear): Longitudinal wind internal pressure (IPLW)

Node 1 13

X-Axis Force -3.013 3.013

Y-Axis Force -11.250 -11.250





Load Reac

0.000 0.000

22.500 -22.500

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil -2.647E-13 Resid 3.944E-13

0.000E+00 2.132E-13

0.000E+00 0.000E+00

0.000E+00

0.000E+00

2.025E-13

Load case 8 (Linear): Lumped masses (DL+LL)

762


Node 1 13

X-Axis Force 3.777 -3.777

Y-Axis Force 14.005 14.005





Load Reac

0.000 0.000

-28.009 28.009

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil Resid

1.635E-13 3.340E-13

0.000E+00 7.816E-14

0.000E+00 0.000E+00

0.000E+00

0.000E+00

9.415E-14

Load case 9 (Spectral) Spectral load case

Node 1 13

X-Axis Force -0.118 -0.118

Y-Axis Force -0.239 0.239





Reac

0.236

0.000

0.000

0.000

0.000

0.000

Load case 10 (Non-linear): 1.25DL+1.5LL Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.988% Cnv (Res gov) Node 1 3 6 7 8 11 13

X-Axis Force 40.644 0.000 0.000 0.000 0.000 0.000 -40.644

Y-Axis Force 77.150 -0.003 0.002 0.009 0.002 -0.003 77.150

Z-Axis Force 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 0.000 0.004 0.000 -0.004 0.000 0.000

Load Reac

0.000 0.000

-154.300 154.300

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil Resid

7.114E-11 1.508E-04

0.000E+00 8.702E-03

0.000E+00 0.000E+00

0.000E+00

0.000E+00

3.605E-03

Load case 11 (Non-linear): 0.8DL+CW+IPCW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.987% Cnv (Res gov) Node 1 3 6 7 8 11

X-Axis Force -77.731 -0.005 0.000 0.000 0.000 0.008

Y-Axis Force -111.210 0.001 -0.001 -0.015 -0.006 0.009

Z-Axis Force 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.001 -0.002 -0.006 -0.001 0.006 -0.001

763

SPACE GASS 12 User Manual 13

-1.375

-65.373

0.000

0.000

0.000

0.000

Load Reac

79.112 -79.107

176.582 -176.582

0.000 0.000

0.000 0.000

0.000 0.000

3.990 0.000

Equil Resid

5.348E-03 7.552E-03

0.000E+00 1.502E-02

0.000E+00 0.000E+00

0.000E+00

0.000E+00

6.465E-03

Load case 12 (Non-linear): 1.25DL+CW+ISCW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.995% Cnv (Res gov) Node 1 3 6 7 8 11 13

X-Axis Force -43.143 0.003 0.000 0.000 0.000 -0.003 -35.968

Y-Axis Force 13.908 0.002 -0.001 -0.001 0.001 -0.001 61.573

Z-Axis Force 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 0.000 -0.001 0.001 0.000 -0.001 0.000

Load Reac

79.112 -79.112

-75.481 75.481

0.000 0.000

0.000 0.000

0.000 0.000

3.994 0.000

Equil Resid

5.341E-04 3.230E-03

0.000E+00 1.762E-03

0.000E+00 0.000E+00

0.000E+00

0.000E+00

8.404E-04

Load case 13 (Non-linear): 0.8DL+LW1+IPLW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.988% Cnv (Res gov) Node 1 3 6 7 8 11 13

X-Axis Force -14.709 0.000 0.000 0.000 0.000 0.000 14.709

Y-Axis Force -54.034 0.002 -0.002 -0.007 -0.002 0.002 -54.034

Z-Axis Force 0.000 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 0.000 -0.003 0.000 0.003 0.000 0.000

Load Reac

0.000 0.000

108.068 -108.068

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil Resid

3.368E-11 1.201E-04

0.000E+00 6.997E-03

0.000E+00 0.000E+00

0.000E+00

0.000E+00

3.039E-03

Load case 14 (Non-linear): 1.25DL+LW2+ISLW Non-linear (Small, Sec, Resid): P- P- 4 Itns, 99.983% Cnv (Res gov) Node 1

764

X-Axis Force 28.268

Y-Axis Force 86.713

Z-Axis Force 0.000

X-Axis Moment 0.000

Y-Axis Moment 0.000

Z-Axis Moment 0.000

Portal Frame Analysis 3 6 7 8 11 13

0.000 0.000 0.000 0.000 0.000 -28.268

-0.005 0.004 0.015 0.004 -0.005 86.713

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.006 0.000 -0.006 0.000 0.000

Load Reac

0.000 0.000

-173.425 173.425

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Equil Resid

8.475E-11 2.542E-04

0.000E+00 1.466E-02

0.000E+00 0.000E+00

0.000E+00

0.000E+00

6.321E-03

765


Static analysis report (enveloped) This report extract covers the same information as the previous section except that the results are enveloped. It allows you to quickly locate the maximum and minimum values together with their coincident values. Note the summary envelopes at the end of each section which show the overall maximums and minimums for all selected nodes and members. NODE DISPLACEMENTS (mm,rad) ------------------ (*=Maximum, #=Minimum) Envelope = Load Cases 1-9 and All Nodes Node 1

766

Load Case 2 3

X-Axis Transl'n 0.000 0.000

Y-Axis Transl'n 0.000 0.000

Z-Axis Transl'n 0.000 0.000

X-Axis Rotation 0.000 0.000

Y-Axis Rotation 0.000 0.000

Z-Axis Rotation 0.002 -0.018

2

3 2 3 2 2 3

63.213* -6.194# 63.213 -6.194 -6.194 63.213

0.117 -0.048 0.117* -0.048# -0.048 0.117

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.014 0.001 -0.014 0.001 0.001 -0.014

3

3 2 3 2 4 3

99.246* -3.698# 99.246 -3.698 6.504 99.246

0.234 -0.097 0.234* -0.097# 0.200 0.234

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.004 -0.003 -0.004 -0.003 0.005 -0.004

4

3 2 4 2 4 2

98.835* -3.193# 5.584 -3.193 5.584 -3.193

-3.476 -5.540 9.951* -5.540# 9.951 -5.540

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.001 -0.004 0.007 -0.004 0.007 -0.004

5

3 2 4 2 4 2

98.245* -2.629# 4.560 -2.629 4.560 -2.629

-0.524 -13.435 24.370* -13.435# 24.370 -13.435

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.004 -0.006 0.010 -0.006 0.010 -0.006

6

3 2 4 2 4 2

96.822* -1.532# 2.597 -1.532 2.597 -1.532

27.786 -35.183 64.155* -35.183# 64.155 -35.183

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.013 -0.008 0.015 -0.008 0.015 -0.008


7

3 4 4 2 3 2

93.373* 0.000# 0.000 0.000 93.373 0.000

96.251 118.858 118.858* -66.190# 96.251 -66.190

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.005 0.000 0.000 0.000 0.005 0.000

8

3 4 3 2 2 4

92.581* -2.597# 92.581 1.532 1.532 -2.597

78.638 64.155 78.638* -35.183# -35.183 64.155

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.010 -0.015 -0.010 0.008 0.008 -0.015

9

3 4 3 2 2 3

90.748* -4.560# 90.748 2.629 2.629 90.748

42.540 24.370 42.540* -13.435# -13.435 42.540

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.013 -0.010 -0.013 0.006 0.006 -0.013

10

3 4 3 2 2 3

89.618* -5.584# 89.618 3.193 3.193 89.618

21.016 9.951 21.016* -5.540# -5.540 21.016

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.013 -0.007 -0.013 0.004 0.004 -0.013

11

3 4 4 2 2 3

88.460* -6.504# -6.504 3.698 3.698 88.460

0.084 0.200 0.200* -0.097# -0.097 0.084

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.013 -0.005 -0.005 0.003 0.003 -0.013

12

3 4 4 2 4 3

43.844* -10.251# -10.251 6.194 -10.251 43.844

0.042 0.100 0.100* -0.048# 0.100 0.042

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.012 0.002 0.002 -0.001 0.002 -0.012

13

4 3

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

0.003 -0.012

3 12 7 7 6 1

3 4 4 2 4 3

0.234 0.100 118.858* -66.190# 64.155 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.004 0.002 0.000 0.000 0.015 -0.018

0.000 0.000 99.246* -10.251# 0.000 0.000 2.597 0.000

MEMBER FORCES AND MOMENTS (kN,kNm)

767

SPACE GASS 12 User Manual ------------------------- (*=Maximum, #=Minimum) Envelope = Load Cases 10-14 and All Members and All Sections The following maximums and minimums are taken from either end of the member Memb

768

Load Case

Axial Force

Y-Axis Shear

Z-Axis Shear

X-Axis Torsion

Y-Axis Moment

Z-Axis Moment

1

14 11 11 14 11 10

86.713* -113.935# -111.210 82.455 -113.935 72.892

-28.268 71.656 77.731* -44.806# 71.656 -40.644

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 272.886 -0.001 -138.160 272.886 -153.483

2

14 11 11 14 11 14

82.455* -116.660# -113.935 78.197 -116.660 78.197

-44.806 65.587 71.662* -61.343# 65.587 -61.343

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-138.160 526.758 272.885 -336.781 526.758 -336.781

3

14 11 14 11 11 14

65.332* -71.697# 65.332 -71.579 -71.579 65.332

74.891 -97.131 74.891* -113.084# -113.084 74.891

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-325.836 343.477 -325.836 514.769 514.769 -325.836

4

14 11 14 11 11 14

65.187* -71.869# 65.187 -71.756 -71.756 65.187

64.116 -81.016 64.116* -97.084# -97.084 64.116

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-215.576 203.508 -215.576 347.913 347.913 -215.576

5

14 11 14 11 11 14

64.996* -72.025# 64.996 -71.849 -71.849 64.996

53.573 -50.958 53.573* -81.028# -81.028 53.573

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-125.205 17.416 -125.205 211.094 211.094 -125.205

6

14 11 14 11 10 11

64.715* -72.381# 64.715 -72.015 40.765 -72.381

35.159 -1.128 35.159* -50.973# 1.242 -1.128

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

10.882 -127.088 10.882 17.423 118.633 -127.088

7

14 11

64.715* -71.867#

-35.159 -8.690

0.000 0.000

0.000 0.000

0.000 0.000

10.882 -127.088

Portal Frame Analysis 11 14 10 11

-71.501 64.715 40.765 -71.867

32.142* -35.159# -1.242 -8.690

0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000

-50.702 10.882 118.633 -127.088

8

14 11 11 14 13 12

64.996* -71.507# -71.332 64.996 -55.787 38.289

-53.573 32.122 49.258* -53.573# 41.664 -36.594

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-125.205 -50.708 66.786 -125.205 92.446 -133.038

9

14 11 11 14 13 14

65.187* -71.344# -71.231 65.187 -55.684 65.187

-64.116 49.241 58.257* -64.116# 49.198 -64.116

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-215.576 59.254 144.881 -215.576 159.966 -215.576

10

14 11 11 14 13 14

65.332* -71.195# -71.077 65.332 -55.536 65.332

-74.891 58.302 67.204* -74.891# 56.667 -74.891

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-325.836 140.473 241.074 -325.836 242.455 -325.836

11

14 11 14 11 11 14

82.455* -70.823# 78.197 -70.823 -70.823 78.197

44.806 -67.473 61.343* -67.473# -67.473 61.343

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-138.160 252.982 -336.781 252.982 252.982 -336.781

12

14 11 14 13 13 10

86.713* -68.098# 82.455 -56.759 -56.759 72.892

28.268 -33.050 44.806* -33.609# -33.609 40.644

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 61.588 -138.160 90.108 90.108 -153.483

1 2 1 3 2 2

14 11 11 11 11 14

86.713* -116.660# -111.210 -71.579 -116.660 78.197

-28.268 65.587 77.731* -113.084# 65.587 -61.343

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 526.758 -0.001 514.769 526.758 -336.781

Z-Axis

X-Axis

Y-Axis

Z-Axis

NODE REACTIONS (kN,kNm) -------------- (*=Maximum, #=Minimum) Envelope = Load Cases 1-9 and All Nodes Load

X-Axis

Y-Axis

769

SPACE GASS 12 User Manual Node 1

Case 2 3 2 3 3 4

Force 18.261* -70.889# 18.261 -70.889 -70.889 -20.355

Force 30.375 -73.554 30.375* -73.554# -73.554 -63.000

Force 0.000 0.000 0.000 0.000 0.000 0.000

Moment 0.000 0.000 0.000 0.000 0.000 0.000

Moment 0.000 0.000 0.000 0.000 0.000 0.000

Moment 0.000 0.000 0.000 0.000 0.000 0.000

3

5 3 6 3 2 3

0.000* 0.000# 0.000 0.000 0.000 0.000

0.000 0.000 0.000* 0.000# 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

6

2 3 3 4 1 6

0.000* 0.000# 0.000 0.000 0.000 0.000

0.000 0.000 0.000* 0.000# 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

7

3 4 2 3 6 3

0.000* 0.000# 0.000 0.000 0.000 0.000

0.000 0.000 0.000* 0.000# 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

8

2 3 4 2 2 4

0.000* 0.000# 0.000 0.000 0.000 0.000

0.000 0.000 0.000* 0.000# 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

11

2 3 6 4 4 3

0.000* 0.000# 0.000 0.000 0.000 0.000

0.000 0.000 0.000* 0.000# 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

13

4 2 2 4 4 3

20.355* -18.261# -18.261 20.355 20.355 -8.224

-63.000 30.375 30.375* -63.000# -63.000 -26.461

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

13 1 1 1 11

4 3 2 3 4

20.355* -70.889# 18.261 -70.889 0.000

-63.000 -73.554 30.375* -73.554# 0.000

0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000

770

Portal Frame Analysis 3

3

0.000

0.000

0.000

0.000

0.000

0.000

NODE REACTIONS (kN,kNm) -------------- (*=Maximum, #=Minimum) Envelope = Load Cases 10-14 and All Nodes Load Case 10 11 14 11 11 12

X-Axis Force 40.644* -77.731# 28.268 -77.731 -77.731 -43.143

Y-Axis Force 77.150 -111.210 86.713* -111.210# -111.210 13.908

Z-Axis Force 0.000 0.000 0.000 0.000 0.000 0.000

X-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000

Y-Axis Moment 0.000 0.000 0.000 0.000 0.000 0.000

Z-Axis Moment 0.000 0.001 0.000 0.001 0.001 0.000

3

12 11 13 14 12 11

0.003* -0.005# 0.000 0.000 0.003 -0.005

0.002 0.001 0.002* -0.005# 0.002 0.001

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 -0.002 0.000 0.000 0.000 -0.002

6

13 14 14 13 14 11

0.000* 0.000# 0.000 0.000 0.000 0.000

-0.002 0.004 0.004* -0.002# 0.004 -0.001

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.003 0.006 0.006 -0.003 0.006 -0.006

7

11 12 14 11 12 11

0.000* 0.000# 0.000 0.000 0.000 0.000

-0.015 -0.001 0.015* -0.015# -0.001 -0.015

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.001 0.001 0.000 -0.001 0.001 -0.001

8

14 11 14 11 11 14

0.000* 0.000# 0.000 0.000 0.000 0.000

0.004 -0.006 0.004* -0.006# -0.006 0.004

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.006 0.006 -0.006 0.006 0.006 -0.006

11

11 12 11 14 14 11

0.008* -0.003# 0.008 0.000 0.000 0.008

0.009 -0.001 0.009* -0.005# -0.005 0.009

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

-0.001 -0.001 -0.001 0.000 0.000 -0.001

13

13 10

14.709* -40.644#

0.000 0.000

0.000 0.000

0.000 0.000

0.000 0.000

Node 1

-54.034 77.150

771


1 1 1 1 8 8

772

14 11 12 13

-28.268 -1.375 -35.968 14.709

86.713* -65.373# 61.573 -54.034

0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000

10 11 14 11 11 14

40.644* -77.731# 28.268 -77.731 0.000 0.000

77.150 -111.210 86.713* -111.210# -0.006 0.004

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.001 0.000 0.001 0.006 -0.006


Bill of materials report This report extract shows the bill of materials listing that can be produced by SPACE GASS. BILL OF MATERIALS (m,m^2,kg) ----------------Memb 1 2 3 4 5

Sect 1 3 4 2 2

Qty 4 2 2 2 2

Section Name 530 UB 92.4 360 UB 50.7-A 360 UB 50.7-B 360 UB 50.7 360 UB 50.7

Unit Length 3.750 1.632 1.632 2.994 6.259

Total Length 15.000 3.264 3.265 5.988 12.517

Unit Mass 347.362 138.961 124.458 152.070 317.869

Total mass = 2856.165 Centre of gravity = 12.500,5.802,0.000

773

Tota Mas 1389.45 277.92 248.91 304.14 635.73


Dynamic frequency analysis report This report extract shows the natural frequencies and periods for each of the dynamic modes within each mass load case. In this case there was only one mass load case which we analysed for three dynamic modes. DYNAMIC NATURAL FREQUENCIES (Hz,Sec) --------------------------Mass Case 8

774

Mode 1 2 3 4 5 6

Natural Frequency 0.862 1.823 4.879 6.275 6.277 6.757

Natural Period 1.160 0.548 0.205 0.159 0.159 0.148

Frequency Tolerance Iterations 0.000977 11 0.000842 13 0.000890 14 0.000596 14 0.000192 16 0.000766 14


Dynamic spectral response analysis report This report extract shows the general results of a dynamic response spectrum analysis for spectral load case 9. A dynamic spectral response analysis also calculates displacements, forces, moments and reactions just like a static analysis and, for comparison purposes, they are included with the static analysis results in this report. DYNAMIC RESPONSE SPECTRUM (kN,kg,sec,Hz) ------------------------Spectral case 9: Spectral load case Mass load case: Direction vector: Loading code: Auto scaling of base shear: Sign of the results: Probability factor: Hazard factor: Structural ductility factor: Structural perf. factor Spectral curve multiplier: Mode combination method:

Direction X-Axis Y-Axis Z-Axis

Dominant Mode 1 2 1

Mode Direction Shape Vector 1 Vector 2 Vector 3

8 Dx = 1.000, Dy = 0.000, Dz = 0.000 AS1170.4-2007 Off Mode shape 1 (Calculated) 1.000 0.080 2.000 0.770 0.0308 SRSS (Square Root of the Sum of Squares)

Total Static Total Force Mass 0.0864 10998.8020 0.5035 10998.8020 0.0097 1234.6723

MPF for Dominant Mode 92.652% 59.179% 0.000%

Total Mass Part Factor 98.894% 59.179% 0.000%

Base Shear 0.218% 0.000% 0.000%

Damping Factor 5.0% 5.0% 5.0%

Natural Period 1.1603 0.5484 0.2049

Natural Frequency 0.862 1.823 4.879 Total

Mass Part Factor 92.652% 0.000% 6.241% 98.894%

Spectral Curve NEWCASTLE 5% NEWCASTLE 5% NEWCASTLE 5%

775


Buckling analysis report This report extract shows the buckling load factors and the member effective lengths for each combination load case. The primary load cases were not included in the buckling analysis because in real life they could not occur in isolation. Note that member effective lengths are not calculated for load cases 11 and 13 because their buckling load factors are greater than 1000 (beyond the upper limit specified at the start of the analysis). BUCKLING LOAD FACTORS --------------------Load at Case Rotn 10 (X) 11 12 (Y) 13 14 (Y)

Load

Node at

Mode

Factor

Tolerance Iterations Max Trans

1

11.137

0.007812

15

12 (Z)

13

1 1

>1000.0 13.848

0.007812

15

9 (Z)

7

1 1

>1000.0 8.199

0.007812

15

9 (Z)

7

BUCKLING EFFECTIVE LENGTHS (kN,m) -------------------------Load case 10 (Linear): 1.25DL+1.5LL Mode 1

Memb 1 2 3 4 5 6 7 8 9 10 11 12

Pcr 859.200 811.779 487.541 482.688 477.352 468.334 468.334 477.352 482.688 487.541 811.779 859.200

Length 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Ly 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Lz 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Ly 0.000 0.000 0.000 0.000 0.000 0.000

Lz 0.000 0.000 0.000 0.000 0.000 0.000

Load case 12 (Linear): 1.25DL+CW+ISCW Mode 1

776

Memb 1 2 3 4 5 6

Pcr 196.552 137.588 529.091 526.567 524.103 520.293

Length 0.000 0.000 0.000 0.000 0.000 0.000

Node Max

Portal Frame Analysis 7 8 9 10 11 12

528.319 532.181 534.761 536.945 789.717 848.681

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000

Ly 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Lz 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Load case 14 (Linear): 1.25DL+LW2+ISLW Mode 1

Memb 1 2 3 4 5 6 7 8 9 10 11 12

Pcr 710.976 676.063 530.441 529.252 527.689 525.385 525.385 527.689 529.252 530.441 676.063 710.976

Length 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

777

Portal Frame Member Design Portal frame member design This worked example considers the AS4100 member design of the 25m span haunched portal frame which was analysed in the previous appendix. The design is based on the non-linear analysis results of the combination load cases 10 - 14. This appendix considers only the design of the portal frame members. The portal frame analysis and connection design is covered in Portal frame analysis and Portal frame connection design. This example bases the member design directly on the forces and moments obtained from the non-linear analysis. The non-linear analysis results for combination load cases 10 - 14 are included in the static analysis report (itemised) of the portal frame analysis worked example. The portal frame has wall girts spaced at 1200mm and 1700mm, and roof purlins spaced at 1000mm, 1200mm and 800mm as shown in the following drawing. The frame is fully symmetrical about its centre.

779


In order to check deflections, the following maximum limits will be used. Eaves sway limit for serviceability: h/150 Apex sag limit for dead load: L/360 Apex sag limit for live load: L/240 Apex deflection limit for: L/150 serviceability: Eaves sway due to cross wind: 99*(38/60)**2= 40mm = h/188 (Ok). (Vu = 60m/s, Vs = 38m/s) Apex sag due to dead load: 36mm = L/694 (Ok). Apex sag due to live load: 66mm = L/379 (Ok). Apex uplift due to cross wind (96+109)*(38/60)**2 = 82mm = L/305 (Ok). and internal pressure: In order to define the steel member design data for the frame, the following design groups were specified. 780

Portal Frame Member Design

Group 1: Left column Members 1 and 2 Group 2: Left rafter Members 3, 4, 5 and 6 Group 3: Right rafter Members 7, 8, 9 and 10 Group 4: Right column Members 11 and 12 (Haunches have to be checked by hand) Groups 3 and 4 were specified as members 10,9,8,7 and 12,11 (rather than 7,8,9,10 and 11,12) so that the positions and types of flange restraints could be referenced from the column base and the narrow end of the haunch in similar fashion to groups 1 and 2. This was not absolutely necessary, however it made the input of the restraint data for groups 3 and 4 identical to the data for groups 1 and 2.

In the diagram above, the thick grey lines show the four design groups. They are drawn short of their ends so that you can easily see where they start and finish. Even though the haunches can’t be design or checked (because of their varying properties and non-standard shape), they have been included in the rafter groups 2 and 3. They have, however, been excluded from the portion of the rafter being designed or checked by using an I (ignore) zone in the flange restraint data. If the haunch members had simply been omitted from the rafter groups then the group lengths would have been shorter and the compression and bending effective lengths could have been underestimated. All compression effective lengths were calculated by the buckling analysis and automatically transferred into the member design. The advantage of doing it this way is that different effective lengths can be used for each design load case. The alternative is to manually input the effective lengths, however they are then used for every design load case and the design is usually not as efficient. The minor axis (out-of-plane) compression effective lengths were also specified as being braced at each end due to wall and roof bracing that prevents any out-of-plane buckling at the rafter ends. This has the effect of limiting the minor axis compression effective lengths to no longer than the rafter group length. Flange restraints for the columns were placed on the outside (top) flange at each end and at each girt location. Inside (bottom) flange restraints were placed at the column ends. There are no column fly braces and therefore no intermediate inside flange restraints were applied. For each column, the column base plate was assumed to provide full restraint to both column flanges and hence restraint codes of F (full) were specified for both column flanges at the base.

781

SPACE GASS 12 User Manual Because wall bracing and an eaves strut effectively prevented lateral deflection of both flanges at the top of the column and because the rafter provided partial (or full) twist restraint, the restraints applied to the top of the column were assumed to be F (full). In addition, the stiffness of the haunch meant that the restraining effect of the rafter could be considered to be applied at the bottom of the haunch, hence additional flange restraints identical to those at the top of the column were applied to both column flanges at the base of the haunch. An I (ignore) continuous restraint was also applied to the segment from the bottom of the haunch to the top of the column so that it would be ignored during the design. Top flange restraints of L (lateral) were positioned at each purlin location in the rafter design groups, except that the purlins close to the end of the haunch and near the apex were conservatively assumed to be at the ends of the haunch and at the apex. Bottom flange restraints were also positioned at the ends of the haunch and at midspan of the rafter design groups to coincide with fly braces at those locations. Restraint codes of I (ignore) were positioned between the first two rafter flange restraints so that the haunches could be excluded from the calculations. Fly braces were located at the face of the columns and at the apex, and hence the top and bottom flange restraints at the ends of the rafter design groups were assumed to be at least F (full).

The above diagram shows the location and type of all the flange restraints. Note that the effect of the fly brace at midspan could also have been taken into account by specifying a full restraint at the fly brace location on the top flange and not specifying anything on the bottom flange. A full or partial restraint on one flange causes SPACE GASS to automatically place a partial restraint (at least) on the other flange (see also Effective flange restraints). This method would, however increase the kt factor marginally. All of the member design data was input graphically, however it could have been input just as successfully via a datasheet or by importing it from a text data file. For information about the graphical input procedure for steel member design data, see also Steel member input methods. For detailed information about the actual member design data values and settings, see also Steel member design data.

782

Portal Frame Member Design

Member design results The AS4100 member design module running in checking mode was then initiated and the results are shown in the following computer printout. The rafters are satisfactory with load factors of 1.15 and 1.05. The 530 UB 92.4 columns have also passed with load factors of 1.28 on both sides.

The results of a steel member design or check can be shown graphically as in the above diagram. The member colors matched to the legend show that the columns and left rafter have passed with load factors greater than 1.10, while the right rafter has passed with a load factor greater than 1.00. In this example, because the approximate sizes of the columns and rafters were known in advance, it was appropriate to simply run a steel member check rather than a design. If the steel module had been run in design mode instead, the column members may have been selected as slightly less than 530 UB 92.4 because of their load factors being 1.28 and quite a bit greater than 1.00. Thus, if you know that your initial analysis member sizes are close to the final design sizes, the recommended procedure is to run a steel member check first rather than a design. If the check results show that the analysis member sizes are almost correct then it is a simple matter to manually change some of the analysis member sizes and then do a final check to verify that they are correct. Alternatively, if your analysis member sizes have not been chosen carefully, you should run a steel member design and then choose "Update analysis member sizes" from the Steel menu (see also Updating analysis member sizes) to update the analysis data and bring it in line with the design data. You should then iterate the analysis-design procedure until the design member sizes agree with the analysis member sizes.

783


Steel member design report AS4100 1998 STEEL MEMBER SYMBOLS NOTATION ----------------------------------------This report extract shows all of the steel member design input and output data. Group

= An actual member in the real structure which consists of one or more analysis members joined together end-to-end. Segment = A part of the total member length under consideration (usually equals the portion between lateral restraints). Load factor = The ratio of the minimum loads which cause failure to the actual design loads. Grade = Grade of steel. Fy = Yield stress of overall section. Fyw = Yield stress of web. Fu = Ultimate tensile strength. Ltot = Total group length. Lseg = Length of the critical segment in the group. kt (5.6.3) = Twist restraint effective length factor. kl (5.6.3) = Load height effective length factor. kr (5.6.3) = Lateral rotation effective length factor. Le (5.6.3) = Bending effective length for major axis bending. Lx (6.3.2) = Compression effective length for major axis buckling. Ly (6.3.2) = Compression effective length for minor axis buckling. Lz = Torsion effective length. L/r = Slenderness ratio for compression or bending. Arf = Area of bolt holes removed from flanges. Arw = Area of bolt holes removed from web. An = Net area of section. (Gross area less Arf and Arw). Ae (6.2.2) = Effective area of section. Kf (6.2.2) = Form factor for compression members. Kt (7.3) = Correction factor for eccentric effects in tension members. m (5.6.1.1) = Moment modification factor for bending. s (5.6.1.1) = Bending member slenderness reduction factor. cx (6.3.3) = Compression member slenderness reduction factor (major). cy (6.3.3) = Compression member slenderness reduction factor (minor). b (6.3.3) = Compression member section constant. me (8.4.4.1) = Ratio of major axis moments at ends of segment. mx (8.4.2.2) = Ratio of major axis moments at ends of member. my (8.4.2.2) = Ratio of minor axis moments at ends of segment.  (8.3.4) = Index.  (3.4) = Capacity factor. N* = Design axial force (+ve=compression). Vx* = Design major axis shear force (not considered). Vy* = Design minor axis shear force. Mx* = Design major axis bending moment. My* = Design minor axis bending moment. Nt (7.2) = Section capacity in tension. Ns (6.2) = Section capacity in compression. Ncx (6.3.3) = Major axis member capacity in compression. Ncy (6.3.3) = Minor axis member capacity in compression. Vv (5.11) = Shear capacity of web. Mf (5.12.2) = Moment capacity of flanges. Msx (5.2) = Section major axis moment capacity. Msy (5.2) = Section minor axis moment capacity. Mbx (5.6) = Member major axis moment capacity. Mox (8.4.4) = Member out-of-plane major axis moment capacity. Mrx (8.3.2) = Section major axis moment capacity reduced by axial force. Mry (8.3.3) = Section minor axis moment capacity reduced by axial force. Mix (8.4.2.2) = Member in-plane major axis moment capacity. Miy (8.4.2.2) = Member in-plane minor axis moment capacity. Mtx (8.4.5.2) = Lesser of Mrx and Mox. Mcx (8.4.5.1) = Lesser of Mix and Mox.

STEEL MEMBER DESIGN DATA (m) -----------------------Restraint codes are: F => Fixed restraint P => Partial restraint R => Fixed and rotational restraint S => Partial and rotational restraint L => Lateral restraint U => Unrestrained C => Continuous lateral restraint 784 I => Ignore segment Group: 1 Left column Member list: 1,2 Compr'n eff lengths: Major axis => Calculate,

Minor axis

=> Calculate

N* Vx* Mx*

= -71.87 kN = 0.00 kN (not considered) = -133.15 kNm (Compact)

Vy* My*

= =

21.23 kN 0.00 kNm (Compact)

Portal Frame 0.00 kN (6.2) 0.00 kN (6.3.3)

Nt = 1746.90 kN Ncx = 0.00 kN

(7.2) (6.3.3)

Ns = Ncy =

Noz =

(8.4.4.1)

Mo

=

199.02 kNm (5.6.1)

(5.11)

Mf

=

182.91 kNm (5.12.2)

Vv

0.00 kN

=

449.07 kN

Msx = Mbx =

242.19 kNm (5.2) 133.79 kNm (5.6)

Msy = Mox =

45.47 kNm (5.2) 139.30 kNm (8.4.4)

Mrx =

242.19 kNm (8.3.2)

Mry =

45.47 kNm (8.3.3)

Mix =

0.00 kNm (8.4.2.2)

Miy =

0.00 kNm (8.4.2.2)

Mtx =

139.30 kNm (8.4.5.2)

Mcx =

0.00 kNm (8.4.5.1)

Mx* ---- = 0.96 < 1.00 Mox

Member Design

(Pass) Member out-of-plane bending (8.4.4.2)

AS4100 1998 CALCULATIONS FOR GROUP 4 (*=Failure) -----------------------------------Critical load case is Section:

10, out of 10-14

530 UB 92.4 (I or H section, Rolled/SR)

Failure Crit Mode Case

Start Finish Pos'n Pos'n

Section Member Shear

7.000 0.000 7.000

14 10 11

Load Load Case Factor 10 11 12 13 14

1.28 2.91 1.44 2.83 1.33

Grade= Fyw = Ltot = kt = kr = Lx = Lz = Lx/rx=

7.000

Axial Force

Major Shear

Minor Shear

Major Moment

78.76 77.15 -70.46

0.00

59.14

0.00

-62.88

-306.87 -285.35 220.00

Member Member Member Member Member

300 320.0 7.500 1.03 1.00 35.676 7.000 164.6

-

2.08 1.28 14.89 (1.00)

Member out-of-plane bending (8.4.4.1) Section bending about X-axis (8.3.2) Member out-of-plane bending (8.4.4.1) Section bending about X-axis (8.3.2) Member out-of-plane bending (8.4.4.1)

MPa m (5.6.3) (5.6.3) m (Compression) m (Torsion) (Compression)

Fy Fu Lseg kl Le Ly

= = = = = =

Le/ry=

300.0 440.0 7.000 1.00 7.224 7.000

MPa MPa m (FP Top-Bot) (5.6.3) m (Bending) (5.6.3) m (Compression)

160.9 (Bending)

= 0.0 mm^2 = 11800.0 mm^2 = 0.93 (6.2.2)

Arw Ae Kt

= 0.0 mm^2 = 10955.5 mm^2 (6.2.2) = 1.00 (7.3)

m

=

1.80 (5.6.1.1)

s

=

cx

=

0.23 (6.3.3)

cy

=

0.25 (6.3.3)

b

=

0.00 (6.3.3)

me

=

0.00 (8.4.4.1)

0.37 (5.6.1.1)

mx

=

0.00 (8.4.2.2)

my

=

0.00 (8.4.2.2)



=

0.00 (8.3.4)



=

0.90 (3.4)

N* Vx* Mx*

= 77.15 kN (Slender) = 0.00 kN (not considered) = -285.35 kNm (Compact)

Nt

=

0.00 kN

Ncx =

671.54 kN

Noz =

0.00 kN

=

0.00 0.00 0.00

Failure Mode

Arf An Kf

Vv

Minor Load Moment Factor

936.53 kN

Vy* My*

= =

40.64 kN 0.00 kNm (Compact)

(7.2)

Ns

(6.3.3)

Ncy =

739.85 kN

(8.4.4.1)

Mo

=

298.41 kNm (5.6.1)

(5.11)

Mf

=

455.47 kNm (5.12.2)

= 2957.99 kN

(6.2) (6.3.3)

Msx =

639.90 kNm (5.2)

Msy =

92.24 kNm (5.2)

Mbx =

422.74 kNm (5.6)

Mox =

378.66 kNm (8.4.4)

Mrx =

639.90 kNm (8.3.2)

Mry =

92.24 kNm (8.3.3)

Mix =

621.73 kNm (8.4.2.2)

Miy =

82.62 kNm (8.4.2.2)

Mtx =

0.00 kNm (8.4.5.2)

Mcx =

378.66 kNm (8.4.5.1)

Mx* ---- = 0.75 < 1.00 Mox

(Pass) Member out-of-plane bending (8.4.4.1)

785

Portal Frame Connection Design Portal frame connection design This worked example considers the AS4100 connection design of the 25m span haunched portal frame which was analysed in a previous appendix. The design is based on the nonlinear analysis results of the combination load cases 10 - 14. This appendix considers only the design of the portal frame connections. The portal frame analysis and member design is covered in Portal frame analysis and Portal frame member design. This example bases the member design directly on the forces and moments obtained from the non-linear analysis. The non-linear analysis results for combination load cases 10 - 14 are included in the static analysis report (itemised) of the portal frame analysis worked example. The portal frame has wall girts spaced at 1200mm and 1700mm, and roof purlins spaced at 1000mm, 1200mm and 800mm as shown in the following drawing. The frame is fully symmetrical about its centre.

787


788

Portal Frame Connection Design

Connection design results The summary results of the steel connections design are as follows. More detailed reports can also be produced.

Left Baseplate

Left Knee

789


Ridge

Right Knee

790


Right Baseplate STEEL CONNECTION DESIGN DATA ---------------------------CONNECTION 1 - LEFT BASEPLATE ----------------------------Member:

1

Strength Grade:

Normal

Dimensions (LxWxT): 575x250x20 mm Plate Strength Grade: Normal Full Contact: YES

Fy:

350 MPa

Welds: Weld Strength Grade:

6 mm Normal

Weld Category: Weld Inside Flange:

SP NO

Bolts: Bolt Threads: Bolts: Pitch: Prying Factor:

M24 Include 4 360 mm 0.71

Bolt Procedure: Bolt Strength Grade: Embedded Length: Gauge:

Snug Normal 195 mm 140 mm

Concrete: Concrete: Dimensions (LxWxD):

CONCRETE-20 775x450x395 mm

Type:

Rectangular

Grout: Thickness:

20 mm

Fc:

25 MPa

Strength Grade: Strength Grade:

Normal Normal

CONNECTION 3 - LEFT KNEE -----------------------Connection Type:

Bolted End Plate

Supporting Member: Supported Member:

2 3

Haunch (D/Bb/Tb/Tw): Haunch Length:

333.1/171/11.5/7.3 mm 3000 mm Use Stitch Bolt:

NO

791

SPACE GASS 12 User Manual Stiffen web if necessary Stiffen flange if necessary Dimensions (LxWxT): 885x195x25 mm Plate Strength Grade: Normal

Fy:

250 MPa

Bolt Procedure: Bolt Strength Grade: Bot Bolts (out/in): Pitch inside: Vert Edge Dist: Dist to Flange in:

Bearing High 2/4 80 mm 30 mm 65 mm

Length: Fy:

0 mm 260 MPa

Weld Category:

GP

Length:

0 mm

Length: Fy:

0 mm 260 MPa

Weld Category:

GP

Length:

0 mm

Fy:

250 MPa

8 mm Normal

Weld Category:

GP

6 7


Normal Normal

Fy:

250 MPa

Web Welds: Weld Strength Grade:

6 mm Normal



Flange Weld Type:

Butt

Web Weld Type:

Butt

End Plate Stiffened:

NO

Bolts: Bolt Threads: Top Bolts (out/in): Pitch outside: Gauge: Dist to Flange out: Bolt Head Side:

M20 Include 2/4 0 mm 120 mm 65 mm Default

Top Web Stiffener: Dimensions (WxT): 84x12 mm Plate Length: Full Plate Strength Grade: Normal Welds: Weld Strength Grade: Weld Length:

8 mm Normal Full

Bottom Web Stiffener: Dimensions (WxT): 84x12 mm Plate Length: Full Plate Strength Grade: Normal Welds: Weld Strength Grade: Weld Length:

8 mm Normal Full

Flange Doubler: Position: Both Dimensions (LxWxT): 361.52x70x16 mm Plate Strength Grade: Normal Welds: Weld Strength Grade: CONNECTION 7 - RIDGE -------------------Supported Member 1: Supported Member 2:

Dimensions (LxWxT): 550x200x25 mm Plate Strength Grade: Normal Flange Weld Type:

Butt

Web Weld Type: Weld Category:

Fillet SP


NO



792


CONNECTION 11 - RIGHT KNEE -------------------------Connection Type:

Bolted End Plate

Supporting Member: Supported Member:

11 10

Haunch (D/Bb/Tb/Tw): Haunch Length:

333.1/171/11.5/7.3 mm 3000 mm Use Stitch Bolt:


Normal Normal

NO

Stiffen web if necessary Stiffen flange if necessary Dimensions (LxWxT): 885x195x25 mm Plate Strength Grade: Normal Flange Weld Type:

Butt

Web Weld Type: Weld Category:

Fillet SP


NO



Top Web Stiffener: Dimensions (WxT): 86x6 mm Plate Length: Full Plate Strength Grade: Normal Welds: Weld Strength Grade: Weld Length:

6 mm Normal Full

Bottom Web Stiffener: Dimensions (WxT): 86x6 mm Plate Length: Full Plate Strength Grade: Normal Welds: Weld Strength Grade: Weld Length:

6 mm Normal Full

Flange Doubler: Position: Both Dimensions (LxWxT): 275x72x12 mm Plate Strength Grade: Normal Welds: Weld Strength Grade:

6 mm Normal

Fy:

250 MPa

Web Welds: Weld Strength Grade:

6 mm Normal



Length: Fy:

0 mm 280 MPa

Weld Category:

GP

Length:

0 mm

Length: Fy:

0 mm 280 MPa

Weld Category:

GP

Length:

0 mm

Fy:

260 MPa

Weld Category:

GP

Strength Grade:

Normal

Fy:

350 MPa

CONNECTION 13 - RIGHT BASEPLATE ------------------------------Member:

12

Dimensions (LxWxT): 575x250x20 mm Plate Strength Grade: Normal Full Contact: YES

793

SPACE GASS 12 User Manual Welds: Weld Strength Grade:

6 mm Normal

Weld Category: Weld Inside Flange:

SP NO

Bolts: Bolt Threads: Bolts: Pitch: Prying Factor:

M20 Include 4 360 mm 0.71

Bolt Procedure: Bolt Strength Grade: Embedded Length: Gauge:

Snug Normal 195 mm 120 mm

Concrete: Concrete: Dimensions (LxWxD):

CONCRETE-20 775x450x395 mm

Type:

Rectangular

Grout: Thickness:

20 mm

Fc:

25 MPa

AS4100 STEEL CONNECTION DESIGN SUMMARY (*=Failure, #=Warning) -------------------------------------- ($=Min design action non-compliance) (D=Design, C=Check) Plate or Seat/Cleat

Bolts

Welds

Base Plate 575x250x20 mm

4M24 4.6N/S

6 mm CFW SP

3 D# Left knee

Plate 885x195x25 mm Stiffener Top 84x12 mm Stiffener Bot 84x12 mm Flange Doublers 70x16 mm

7 D

Ridge

11 D

13 D

Conn 1 D

Title/Type Left baseplate

11

0.76

12M20 Web welds 8.8N/TB FSBW SP Flange welds FSBW SP

11

0.92

550x200x25 mm

8M20 Web weld 8.8N/TB 6 mm CFW SP Flange weld FSBW SP

10

0.88

Right knee

Plate 885x195x25 mm Stiffener Top 86x6 mm Stiffener Bot 86x6 mm Flange Doublers 72x12 mm

8M20 Web welds 8.8N/TB 6 mm CFW SP Flange welds FSBW SP

14

0.96

Right baseplate

Base Plate 575x250x20 mm

4M20 4.6N/S

10

0.57

6 mm CFW SP

AS4100 CALCULATIONS FOR CONNECTION 1 - LEFT BASEPLATE ----------------------------------------------------Design/Check: Design Critical load case: 11 out of 10-14 Utilization ratio: 0.76 Supported d bf tf tw r fyf fyw

= = = = = = = =

Base plate

= 575x250x20 mm (Fy = 250 MPa, Fu = 410 MPa)

794

Crit Stress Case Ratio

530 UB 92.4 533 mm 209 mm 15.6 mm 10.2 mm 14 mm 300 MPa 320 MPa

Pass


Weld:

= 6 mm CFW SP (Fu = 410 MPa)

Bolt:

= 4M24 4.6N/S sp = 360 mm lec = 195 mm

sg = 140 mm

Concrete:

CONCRETE-20 (Length = 775 mm, Width = 450 mm, Depth = 395 mm)

Grout:

Strength = 25 MPa, Thickness = 20 mm

Design actions: N* Vy* Vz* My* Mz* Check 8:

= = = = =

111.21 kN Tension (Not used) 77.73 kN 0 kN 0 kNm (Not used) 0 kNm (Not used)

Base plate tension yielding Yield line factor alpha = 8.86 mm fNtp = 797.77 kN fNtp > 111.21 kN

Check 9:

Pass

Capacity of weld at column base fVw = 0.83 kN/mm Resultant stress = 0.14 kN/mm fVw > Resultant Stress

Check 10:

Pass

Capacity of anchor bolts in tension fNtb = 320.81 kN Nt = 111.21 kN fNtb > Nt

Pass

fNct = 258.05 kN fNtf = 112.96 kN fNct > fNtf Check 7:

Pass

Shear transfered by anchor bolts nbv = 2 nbt = 4 fVfb = 51.43 kN fVcex = 29.16 kN fVcey = 60.8 kN fVcp = 580.33 kN Vres = 77.73 kN

Check 11:

fVfb > Vres / nbv

Pass

fVcex > Vx / nbt

Pass

fVcey > Vy / nbt

Pass

fVcpx > Vx / nbt

Pass

fVcpy > Vy / nbt

Pass

Anchor bolts for horizontal shear and tension Check 10 must be satisfied: Check 7 must be satisfied: (A)^2 + (B)^2 < 1 A = Vres / (nbv x fVfb) B = Nt / (fNtb)

AS4100 CALCULATIONS FOR CONNECTION 3 - LEFT KNEE -----------------------------------------------Design/Check: Design Critical load case: 11 out of 10-14 Utilization ratio: 0.92

Pass Pass Pass

Pass

795

SPACE GASS 12 User Manual Supported d bf tf tw r fyf fyw

= = = = = = = =

360 UB 50.7-A 689.1 mm 171 mm 11.5 mm 7.3 mm 11.4 mm 300 MPa 320 MPa

Supporting d bf tf tw r fyf fyw

= = = = = = = =


Angle

= 2.99°

End plate

= 885x195x25 mm (Fy = 250 MPa, Fu = 410 MPa)

Transverse stiffeners Top = 84x12 mm Bottom = 84x12 mm Web welds Flange welds Top stfr. welds Bot stfr. welds

= = = =

FSBW FSBW 8 mm 8 mm

SP (Fu SP (Fu CFW GP CFW GP

= 410 = 410 (Fu = (Fu =

MPa) MPa) 410 MPa) 410 MPa)

Bolts

= 12M20 8.8N/TB (Fu = 830 MPa)

sg sp2 spo ae

= = = =

120 mm 141.52 mm 65 mm 30 mm

sp1 sp3 spi

= 0 mm = 80 mm = 65 mm

Column flange doubler plate Size = 70x16 mm Design actions: N* Vy* Vz* My* Mz*

= = = = =

71.58 kN Tension -116.66 kN (Actual = -116.66 kN, Minimum = 40 kN) 0 kN (Not used) 0 kNm (Not used) -514.77 kNm (Actual = -514.77 kNm, Minimum = 268.2 kNm)

Design moment > Member section capacity Check 1: Detailing requirement Plate depth End plate width bi >= bfb + 20 mm bi <= bfc + 20 mm Bolt gauge sg <= bfb sg <= bfc - 2.5 * df sg >= 120 mm Bolt pitches sp1, sp2, sp3 >= 70 mm Edge distance aev >= 1.5 * df aev <= 2.5 * df aeh >= 1.25 * df Check limits Table 3 - ASI Connection Design Guide 12

Warning

Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass

Check 2: Flange welds to beam Full penetration butt weld - No design check neccessary Check 3: Web welds to beam Full penetration butt weld - No design check neccessary Check 4: Bolts at tension flange Design requirement: ratio fMbt > M* + Maxial* 0.88 Tension bolt moment capacity, fMbt = 613.24 kNm End plate design moment, M* = -514.77 kNm Maxial* = 22.22 kNm Single bolt tension capacity = 162.68 kN Sum of bolt lever arms = 1884.8 mm

796

Pass


Check 5: Bolts in shear Design requirement: ratio fVfb = 555.77 kN > Vv = -116.66 kN 0.21 Total shear resisted by bolts, Vv* = -116.66 kN Single bolt shear capacity, fVdf = 92.63 kN End plate bearing capacity, fVbi = 276.75 kN No. bolts effective in shear = 6 Check 6: End plate at tension flange Design requirement: ratio fMpt > 1.11 * Min [fMbt and fMs] 0.82 End plate yield capacity, fMpt = 679.84 kNm Bolt moment capacity, fMbt = 613.24 kNm Section moment capacity, fMs = 502.87 kNm Check 7: End plate in shear Design requirement: ratio fVpe > Nft / nbp 0.48 fVpu > Nft / nbp 0.32 Horizontal shear yielding capacity, fVpe = 548.44 kN Horizontal shear rupture capacity, fVpu = 835.79 kN Total design tension force, Nft = 791.46 kN Total of bolt rows resisting tension force, nbp = 3

Pass

Pass

Pass Pass

Check 8: Stiffener for end plate N/A - No end plate stiffener Check 9: Design capacity of stiffener welds to end plate N/A - No end plate stiffener Check 10: Local bending of column flange at beam tension flange Design requirement: ratio fMct > 1.11 * Min [fMbt and fMs] 1.54 Stiffener Column flange capacity, fMct = 362.3 kNm Section moment capacity, fMs = 502.87 kNm Bolt group moment capacity, fMbt = 613.24 kNm Yield line parameter, Yc = 5513.85 mm Check 11: Local yielding of column flange at beam tension flange Design requirement: ratio fRwt > Nft 2.15 Stiffener Unstiffened column web yield capacity, fRwt = 368.08 kN Total design tension force, N*ft = 791.46 kN Top flange to end of column = 97.95 mm Check 12: Local yielding of column flange at beam compression flange Design requirement: ratio fRwy > N*fc 1.75 Stiffener Unstiffened column web yield capacity, fRwy = 414.94 kN Total design compression force, N*fc = 725.87 kN Check 13: Column web cripping at beam compression flange Design requirement: ratio fRwc > N*fc 2.35 Unstiffened column web crippling capacity, fRwc = 309.22 kN Total design compression force, N*fc = 725.87 kN

Stiffener

Check 14: Column web compression buckling Design requirement: ratio fRwb > N*fc 1.03 Stiffener Unstiffened column web compression buckling capacity, fRwb = 705.48 kN Total design compression force, N*fc = 725.87 kN Check 15: Unstiffened column web panel in shear Design requirement: ratio fVc > Vc* 0.77 Design capacity of column web in shear, fVc = 939.44 kN Column web pannel shear force, Vc* = 725.87 kN Column axial capacity, fNs = 3398.4 kN

Pass

Check 16: Local bending of column flange with

797

SPACE GASS 12 User Manual flange doubler plates at beam tension flange Design requirement: ratio fMctd > 1.11 * Min [fMbt and fMs] 0.82 Column (flange+doubler) capacity, fMctd = 679.9 kNm Bolt group design capacity, fMbt = 613.24 kNm Section moment capacity, fMs = 502.87 kNm Yield line parameter, Yc = 5513.85 mm Flange doubler plate requirements: bsd > [bfb - (twc + 2 * rc)] / 2 bsd < [bfc - (twc + 2 * rc) - 2 * fillet rad.] / 2 dsd > tfb + 5.0 * (ti + tfc + td)

Pass

Pass Pass Pass

Check 17: Local yielding of column web with plates at beam tension flange N/A - no web with doubler plate at beam tension flange Check 18: Local yielding of column web with plates at beam compression flange N/A - no web with doubler plate at beam compression flange Check 19: Crippling of column web with doubler plate at beam compression flange N/A - no web with doubler plate at beam compression flange Check 20: Compression buckling of column web with doubler plates N/A - no web with doubler plate Check 21: Column web panel with doubler plates in shear N/A - no web with doubler plate Check 22: Column with transverse stiffeners Design requirement: fMcts > 1.11 * Min [fMbt and fMs] fRfts > N*ts fRftw > N*ts Geometry check for trans. stiffeners: bs >= (bfb-twb) / 2 bs >= (bfb / 3 - twc / 2) bs <= (bfc-twc) / 2 ds >= 1.8 * bs ts >= 0.5 * tfb fMcts = 908.99 kNm fMbt = 613.24 kNm, fMs = 502.87 kNm Nts = 423.38 kN fRfts = 471.74 kN, fRftw = 460.89 kN Yield line parameter, Ycs = 7371.78 mm

at tension flange ratio 0.61 0.9 0.92

Check 23: Column with transverse stiffeners Design requirement: Stiffener: fRfcy > N*cs fRfcb > N*cs Welds to stiffeners: fRfcw > N*cs - fRwy Geometry check for trans. stiffeners: bs >= (bfb-twb) / 2 bs >= (bfb / 3 - twc / 2) bs <= (bfc-twc) / 2 ds >= 1.8 * bs ts >= 0.5 * tfb fRfcy = 894.54 kN, fRfcb = 1223.95 kN Ncs = 725.87 kN fRfcw = 1575.72 kN, fRwy = 414.94 kN

at compression flange ratio

Pass Pass Pass Pass Pass Pass Pass Pass

0.81 0.59

Pass Pass

0.2

Pass Pass Pass Pass Pass Pass

Check 24: Column with transverse diagonal shear stiffeners N/A - no web with transverse plate

AS4100 CALCULATIONS FOR CONNECTION 7 - RIDGE -------------------------------------------Design/Check: Design Critical load case: 10 out of 10-14 Utilization ratio: 0.88

798

Pass


Supported d bf tf tw r fyf fyw

= = = = = = = =

360 UB 50.7 356 mm 171 mm 11.5 mm 7.3 mm 11.4 mm 300 MPa 320 MPa

Angle

= 5.99°

End plate

= 550x200x25 mm (Fy = 250 MPa, Fu = 410 MPa)

Flange welds

= FSBW SP (Fu = 410 MPa)

Web welds


Bolts

= 8M20 8.8N/TB (Fu = 830 MPa)

sg sp2 spo ae

= = = =

120 mm 141.52 mm 65 mm 30 mm

Design actions: N* Vy* Vz* My* Mz* Check 1: End plate: Bolt gauge: Edge dist.:

= = = = =

sp1 sp3 spi

-40.77 kN Compression 67.36 kN (Actual = -1.24 kN, Minimum = 67.36 kN) 0 kN (Not used) 0 kNm (Not used) -118.63 kNm (Actual = -118.63 kNm, Minimum = 114.88 kNm)

Detailing limitations bi >= bf + 20 sg <= bf sg >= 120 mm sp2 >= 70 mm ae >= 30 mm ae <= 2.5 bolt diameter 40 mm <= spo <= 75 mm Spacing for bolt at haunch is not sufficient Plate depth

Check 2:

Capacity of welds to beam flanges Check not required for butt weld

Check 3:

Capacity of welds to beam web Web axial force, Nw = -15.98 kN Web bending moment, Mw = -18.77 kNm Web shear force, Vy = 0.11 kN/mm Web shear force, Vz = -0.61 kN/mm Web resultant shear force = 0.62 kN/mm Weld capacity = 0.83 kN/mm Weld capacity > Resultant shear force

Check 4:

= 0 mm = 0 mm = 65 mm

Pass Pass Pass Pass Pass Pass Pass Pass Pass

Pass

Capacity of bolts at tension flange Single bolt tension capacity = 162.68 kN Number of tension bolts = 4 Sum of bolt lever arms = 689.94 mm fMbt = 224.48 kNm Mdesign = -118.63 kNm Maxial = -6.77 kNm fMbt > |MDesign| + Maxial

Check 5:

Pass

Capacity of bolts in shear Total shear resisted (V*) = 67.36 kN Bolts resisting shear = 4 Bolt capacity (fVdf) = 92.63 kN Bolt group capacity (fVfb) = 370.51 kN fVfb > V*

Pass

799

SPACE GASS 12 User Manual Check 6:

Capacity of end plate at tension flange fMpt = 283.57 kNm fMbt = 224.48 kNm fMs = 229.75 kNm fMpt > 1.11 x Min[fMbt, fMs]

Pass

Check 7:

Capacity of end plate in shear Horiz. shear (Vh*) = 160.89 kN Horiz. shear yield capacity (fVpe) = 562.5 kN Horiz. shear rupture capacity (fVpu) = 863.46 kN Min of [fVpu, fVpe] > Vh* Pass

Check 8:

Requirement for stiffener to end plate No stiffener - check not required

Check 9:

Capacity of stiffener welds to end plate No stiffener - check not required

AS4100 CALCULATIONS FOR CONNECTION 11 - RIGHT KNEE -------------------------------------------------Design/Check: Design Critical load case: 14 out of 10-14 Utilization ratio: 0.96 Supported d bf tf tw r fyf fyw

= = = = = = = =

360 UB 50.7-A 689.1 mm 171 mm 11.5 mm 7.3 mm 11.4 mm 300 MPa 320 MPa

Supporting d bf tf tw r fyf fyw

= = = = = = = =

Angle

= 2.99°

End plate

= 885x195x25 mm (Fy = 250 MPa, Fu = 410 MPa)

Pass


Transverse stiffeners Top = 86x6 mm Bottom = 86x6 mm Web welds Flange welds Top stfr. welds Bot stfr. welds

= = = =

6 mm FSBW 6 mm 6 mm

CFW SP SP (Fu CFW GP CFW GP

(Fu = = 410 (Fu = (Fu =

Bolts

= 8M20 8.8N/TB (Fu = 830 MPa)

sg sp2 spo ae

= = = =

120 mm 141.52 mm 65 mm 30 mm

410 MPa) MPa) 410 MPa) 410 MPa)

sp1 sp3 spi

= 0 mm = 0 mm = 65 mm

Column flange doubler plate Size = 72x12 mm Design actions: N* Vy* Vz* My* Mz*

= = = = =

-65.33 kN Compression 78.19 kN (Actual = 78.19 kN, Minimum = 40 kN) 0 kN (Not used) 0 kNm (Not used) 325.84 kNm (Actual = 325.84 kNm, Minimum = 268.2 kNm)

Check 1: Detailing requirement Plate depth End plate width bi >= bfb + 20 mm bi <= bfc + 20 mm Bolt gauge

800

Pass Pass Pass

Portal Frame Connection Design sg <= bfb sg <= bfc - 2.5 * df sg >= 120 mm

Pass Pass Pass

sp1, sp2, sp3 >= 70 mm

Pass

Bolt pitches Edge distance aev >= aev <= aeh >= Check limits Table 3 -

1.5 * df 2.5 * df 1.25 * df ASI Connection Design Guide 12

Pass Pass Pass Pass

Check 2: Flange welds to beam Full penetration butt weld - No design check neccessary Check 3: Web welds to beam Design requirement: SQRT(vz^2+vy^2) <= fVw Web shear force, Vv = 78.19 kN/mm vz = 0.8 kN/mm, vy = 0.06 kN/mm fVw = 0.83 kN/mm

ratio 0.96

Check 4: Bolts at tension flange Design requirement: ratio fMbt > M* + Maxial* 0.74 Tension bolt moment capacity, fMbt = 441.53 kNm End plate design moment, M* = 325.84 kNm Maxial* = 0 kNm Single bolt tension capacity = 162.68 kN Sum of bolt lever arms = 1357.04 mm Check 5: Bolts in shear Design requirement: ratio fVfb = 370.51 kN > Vv = 78.19 kN 0.21 Total shear resisted by bolts, Vv* = 78.19 kN Single bolt shear capacity, fVdf = 92.63 kN End plate bearing capacity, fVbi = 276.75 kN No. bolts effective in shear = 4 Check 6: End plate at tension flange Design requirement: ratio fMpt > 1.11 * Min [fMbt and fMs] 0.83 End plate yield capacity, fMpt = 589.88 kNm Bolt moment capacity, fMbt = 441.53 kNm Section moment capacity, fMs = 502.87 kNm Check 7: End plate in shear Design requirement: ratio fVpe > Nft / nbp 0.41 fVpu > Nft / nbp 0.27 Horizontal shear yielding capacity, fVpe = 548.44 kN Horizontal shear rupture capacity, fVpu = 835.79 kN Total design tension force, Nft = 449.54 kN Total of bolt rows resisting tension force, nbp = 2

Pass

Pass

Pass

Pass

Pass Pass

Check 8: Stiffener for end plate N/A - No end plate stiffener Check 9: Design capacity of stiffener welds to end plate N/A - No end plate stiffener Check 10: Local bending of column flange at beam tension flange Design requirement: ratio fMct > 1.11 * Min [fMbt and fMs] 1.4 Stiffener Column flange capacity, fMct = 349.93 kNm Section moment capacity, fMs = 502.87 kNm Bolt group moment capacity, fMbt = 441.53 kNm Yield line parameter, Yc = 5325.63 mm Check 11: Local yielding of column flange at beam tension flange Design requirement: ratio fRwt > Nft 1.22 Stiffener Unstiffened column web yield capacity, fRwt = 368.08 kN

801

SPACE GASS 12 User Manual Total design tension force, N*ft = 449.54 kN Top flange to end of column = 97.95 mm Check 12: Local yielding of column flange at beam compression flange Design requirement: ratio fRwy > N*fc 0.65 Pass Unstiffened column web yield capacity, fRwy = 787.64 kN Total design compression force, N*fc = 510.89 kN Check 13: Column web cripping at beam compression flange Design requirement: ratio fRwc > N*fc 0.8 Unstiffened column web crippling capacity, fRwc = 638.73 kN Total design compression force, N*fc = 510.89 kN

Pass

Check 14: Column web compression buckling Design requirement: ratio fRwb > N*fc 0.72 Pass Unstiffened column web compression buckling capacity, fRwb = 705.48 kN Total design compression force, N*fc = 510.89 kN Check 15: Unstiffened column web panel in shear Design requirement: ratio fVc > Vc* 0.54 Design capacity of column web in shear, fVc = 939.44 kN Column web pannel shear force, Vc* = 510.89 kN Column axial capacity, fNs = 3398.4 kN Check 16: Local bending of column flange with flange doubler plates at beam tension flange Design requirement: ratio fMctd > 1.11 * Min [fMbt and fMs] 0.93 Column (flange+doubler) capacity, fMctd = 529.39 kNm Bolt group design capacity, fMbt = 441.53 kNm Section moment capacity, fMs = 502.87 kNm Yield line parameter, Yc = 5325.63 mm Flange doubler plate requirements: bsd > [bfb - (twc + 2 * rc)] / 2 bsd < [bfc - (twc + 2 * rc) - 2 * fillet rad.] / 2 dsd > tfb + 5.0 * (ti + tfc + td)

Pass

Pass

Pass Pass Pass

Check 17: Local yielding of column web with plates at beam tension flange N/A - no web with doubler plate at beam tension flange Check 18: Local yielding of column web with plates at beam compression flange N/A - no web with doubler plate at beam compression flange Check 19: Crippling of column web with doubler plate at beam compression flange N/A - no web with doubler plate at beam compression flange Check 20: Compression buckling of column web with doubler plates N/A - no web with doubler plate Check 21: Column web panel with doubler plates in shear N/A - no web with doubler plate Check 22: Column with transverse stiffeners Design requirement: fMcts > 1.11 * Min [fMbt and fMs] fRfts > N*ts fRftw > N*ts Geometry check for trans. stiffeners: bs >= (bfb-twb) / 2 bs >= (bfb / 3 - twc / 2) bs <= (bfc-twc) / 2 ds >= 1.8 * bs ts >= 0.5 * tfb fMcts = 669.9 kNm fMbt = 441.53 kNm, fMs = 502.87 kNm

802

at tension flange ratio 0.73 0.31 0.23

Pass Pass Pass Pass Pass Pass Pass Pass

Portal Frame Connection Design Nts = 81.46 kN fRfts = 260.06 kN, fRftw = 355.69 kN Yield line parameter, Ycs = 6739.25 mm Check 23: Column with transverse stiffeners Design requirement: Stiffener: fRfcy > N*cs fRfcb > N*cs Welds to stiffeners: fRfcw > N*cs - fRwy Geometry check for trans. stiffeners: bs >= (bfb-twb) / 2 bs >= (bfb / 3 - twc / 2) bs <= (bfc-twc) / 2 ds >= 1.8 * bs ts >= 0.5 * tfb fRfcy = 1044.81 kN, fRfcb = 1030.39 kN Ncs = 510.89 kN fRfcw = 1181.79 kN, fRwy = 787.64 kN

at compression flange ratio 0.49 0.5

Pass Pass

-0.23

Pass Pass Pass Pass Pass Pass

Check 24: Column with transverse diagonal shear stiffeners N/A - no web with transverse plate

AS4100 CALCULATIONS FOR CONNECTION 13 - RIGHT BASEPLATE ------------------------------------------------------Design/Check: Design Critical load case: 10 out of 10-14 Utilization ratio: 0.57 Supported d bf tf tw r fyf fyw

= = = = = = = =

Base plate

= 575x250x20 mm (Fy = 250 MPa, Fu = 410 MPa)

Weld:


Bolt:

= 4M20 4.6N/S sp = 360 mm lec = 195 mm

Pass


sg = 120 mm

Concrete:

CONCRETE-20 (Length = 775 mm, Width = 450 mm, Depth = 395 mm)

Grout:

Strength = 25 MPa, Thickness = 20 mm

Design actions: N* Vy* Vz* My* Mz* Check 1:

= = = = =

-77.15 kN Compression (Not used) 40.64 kN 0 kN 0 kNm (Not used) 0 kNm (Not used)

Capacity for bearing on concrete support Base plate area = 143750 mm^2 Geometrically similar area A2 = 261141.3 mm^2 fNc = 2092.5 kN >= Nc* = 77.15 kN

Check 2:

Pass

Capacity of steel base plate fNs = 3774.15 kN >= Nc* = 77.15 kN a1 = 34.33 mm a2 = 41.4 mm a4 = 83.44 mm a5 = 742 mm kx = 2.271942 X = 0.03850627 lambda = 0.2250999 ao = 41.4 mm

Pass

803


Check 3: Weld length: Weld stress:

Capacity of weld at column base Lx = 418 mm Ly = 947.6 mm Vx = 0 kN/mm Vy = 0.04 kN/mm Plate fully contacts with column SQRT(Vx^2 + Vy^2) = 0.04 kN/mm

Weld strength: fVw = 0.83 kN/mm SQRT(Vx^2 + Vy^2) < fVw Check 4:

Pass

Horizontal shear transfered by fiction Slip factor = 0.4 Compression force = 77.15 kN fVcf = 21.6 kN Vres = 40.64 kN fVcf > Vres is not satisfied - Anchor bolts check is required

Check 7:

Shear transfered by anchor bolts nbv = 2 nbt = 4 fVfb = 35.71 kN fVcex = 27.1 kN fVcey = 55.5 kN fVcp = 548.54 kN Vres = 40.64 kN

804

fVfb > Vres / nbv

Pass

fVcex > Vx / nbt

Pass

fVcey > Vy / nbt

Pass

fVcpx > Vx / nbt

Pass

fVcpy > Vy / nbt

Pass

Cable Analysis Cable analysis This worked example demonstrates the input and analysis of a 30m tall, guyed mast. The catenary cable equations are used to calculate the axial force in a nominal guy member, which is then compared to the result obtained from SPACE GASS.

A non-linear analysis is the only type of analysis that can be performed on a structure containing cable members due to their highly non-linear behaviour. The guyed mast considered in this example has the following basic properties. Height: Number of guys: Radial guy spacing: Guy connections at: Distance from base: Guys: Mast:

30m 3 sets of 3 120 15m, 22.5m and 30m 12m 10mm steel cable 406x9.5CHS

Dead load (DL):

Self weight (calculated by SPACE GASS)

The uniformly distributed dead load is not the only load that the structure would be subject to in real life, however it is the only one considered here. The load cases are limited in order to simplify the example. In this example, the only type of load applied is an UDL. You can apply point loads to cable members, however they must be applied as node loads rather than member concentrated loads.

Elevation of guyed mast

805


Method of input It was not possible to input the guyed mast using the structure wizard due to its unusual geometric configuration. All of the data input was performed using either graphical tools or datasheets. Node restraints and member fixities After the structural geometry was generated, node restraints of FFFFFF were applied to nodes 1, 5, 6 and 7 using the graphical restraint input facility. Even though the guyed members are to be pin connected to the mast and to their base, a member end fixity of FFFFFF was specified. This is because a member end fixity code of FFFRRR would yield the same result as a code of FFFFFF for cable members (ie. cables have no moment capacity). Loads Loading due to the self weight of the structure was input using a datasheet.

Cables have no moment capacity. Hence, intermediate nodes on cables must have all their rotational degrees of freedom restrained (ie. use RRRFFF). Input check As a final check before the analysis was initiated, an output report containing the complete structural data was viewed. Any errors in the data were corrected and the model was then ready for analysis.

806

Cable Analysis

Analysis procedure A non-linear (2nd order) analysis was performed in which both P- and P- effects were activated, while axial shortening was not.

807


Analysis results In the absence of any lateral loads, the guys simply deflect vertically under self weight as shown in the following deformed shape diagram.

SPACE GASS model

808

Cable Analysis

Deformed shape

This report extract shows all of the input data for the model, together with the intermediate displacements, forces and moments for guy member 12. Following the report, we compare the SPACE GASS results for member 12 with a theoretical formular. ANALYSIS STATUS REPORT ---------------------Job name ...... Guyed Mast Location ...... C:\Samples\Mixed This is a guyed mast analysed for the SPACE GASS worked example appendices. Length units ......................... Section property units ............... Material strength units .............. Mass density units ................... Temperature units .................... Force units .......................... Moment units ......................... Mass units ........................... Acceleration units ................... Translation units .................... Stress units .........................

m mm MPa kg/m^3 Celsius kN kNm kg g's mm MPa

809


Nodes ................................ Members .............................. Plates ............................... Restrained nodes ..................... Nodes with spring restraints ......... Section properties ................... Material properties .................. Constrained nodes .................... Member offsets .......................

7 12 0 4 0 2 1 0 0

( ( ( ( ( ( ( ( (

32765) 32765) 32765) 32765) 32765) 5000) 999) 32765) 32765)

Node loads ........................... Prescribed node displacements ........ Member concentrated loads ............ Member distributed forces ............ Member distributed torsions .......... Thermal loads ........................ Member prestress loads ............... Plate pressure loads ................. Self weight load cases ............... Combination load cases ............... Load cases with titles ............... Lumped masses ........................ Spectral load cases ..................

0 0 0 0 0 0 0 0 1 0 0 0 0

( ( ( ( ( ( ( ( ( ( ( ( (

250000) 250000) 250000) 250000) 250000) 250000) 250000) 250000) 10000) 10000) 10000) 250000) 10000)

Static analysis ...................... Dynamic analysis ..................... Response analysis .................... Buckling analysis .................... Ill-conditioned ...................... Non-linear convergence ............... Frontwidth ........................... Total degrees of freedom ............. Static load cases .................... Mass load cases ......................

Y N N N N Y 12 18 1 1

( (

10000) 10000)

NODE COORDINATES (m) ---------------Node

X Coord

Y Coord

Z Coord

1 2 3 4 5 6 7

0.000 0.000 0.000 0.000 -12.000 6.000 6.000

0.000 15.000 22.500 30.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 10.392 -10.392

MEMBER DATA (deg,kNm/rad,m) ----------- (F=Fixed, R=Released) (*=Cable length)

810

Cable Analysis

Memb

Dir Angle

1 2 3 4 5 6 7 8 9 10 11 12

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Dir Dir Memb Node Axis Type Node A Node B Norm Norm Norm Cabl Cabl Cabl Cabl Cabl Cabl Cabl Cabl Cabl

1 2 3 2 3 4 2 3 4 2 3 4

Node A Node B Sect Mat Fixity Fixity

2 3 4 5 5 5 6 6 6 7 7 7

1 1 1 2 2 2 2 2 2 2 2 2

1 1 1 1 1 1 1 1 1 1 1 1

FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF

FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF FFFFFF

Length

15.000 7.500 7.500 19.209 25.500 32.311 19.209 25.500 32.311 19.209 25.500 32.311

NODE RESTRAINTS (kN/m,kNm/rad) --------------- (F=Fixed, R=Released, S=Spring, *=General) Node

Rest Code

1 5 6 7

FFFFFF FFFFFF FFFFFF FFFFFF

X Axial Stiffness

Y Axial Stiffness

Z Axial X Rotation Y Rotation Z Rotati Stiffness Stiffness Stiffness Stiffne

SECTION PROPERTIES (mm,mm^2,mm^4,deg) -----------------Sect 1 2

Name

Mark

Shape

Source

406.4x9.5 CHS Guy

S1 S2

Circular tube Solid circle

Aust300 User

Z-Axis Mom of In

Y-Axis Shr Area

Z-Axis Shr Area

Pri Ang

1 1.1800E+04 4.6700E+08 2.3300E+08 2.3300E+08 2 7.8540E+01 9.8175E+02 4.9087E+02 4.9087E+02

Infinite Infinite

Infinite Infinite

0. 0.

Tt/Tb

Tw/

0.00 0.00 0.00 0.00

9. 0. 0. 0.

Sect

Sect

Area of Section

Torsion Constant

Y-Axis Mom of In

Shape

Trans Mir Rotate

D

1

Circular tube

No

No

0.00

406.00

2

Solid circle

No

No

0.00

10.00

MATERIAL PROPERTIES (MPa,kg/m^3,strain/degC) ------------------Young's Poisson's Matl Material Name Modulus Ratio

Bt/Bb Btw/Bbw 0.00 0.00 0.00 0.00

Mass Density

0.00 0.00 0.00 0.00

Coeff of Expansion

811

Concrete Strength


1

STEEL

2.0000E+05

0.25 7.8500E+03

1.170E-05

SELF WEIGHT (g's) ----------Load Case

X-Axis Accel'n

Y-Axis Accel'n

Z-Axis Accel'n

1

0.000

-1.000

0.000

INTERMEDIATE DISPLACEMENTS (m,mm) -------------------------- (*=Maximum, #=Minimum) Memb 12, Case 1 (Non-linear): Non-linear (Small, Sec, Resid): P-, P-, 2 Itns, 99.963% Cnv (Def gov) Station Location 0.000 3.231 6.462 9.693 12.924 16.155 19.387 22.618 25.849 29.080 32.311

Global X Transl'n 0.000 -32.365 -57.964 -76.646 -88.253 -92.627# -89.600 -79.003 -60.659 -34.387 0.000*

Global Y Transl'n -0.291 -25.718 -46.029 -61.036 -70.545 -74.352# -72.247 -63.998 -49.374 -28.130 0.000*

Global Z Transl'n 0.000 56.059 100.397 132.754 152.860 160.435* 155.192 136.838 105.066 59.561 0.000#

Local X Transl'n 0.270 -0.162 -0.318# -0.260 -0.053 0.233 0.526 0.738 0.786* 0.576 0.000

Local Y Transl'n

Local Z Transl'n

-0.108 -69.653 -124.732 -164.996 -190.083 -199.618# -193.215 -170.474 -130.980 -74.303 0.000*

0.000 0.000 0.000 0.000 0.000 0.000 0.000# 0.000 0.000 0.000* 0.000

INTERMEDIATE FORCES AND MOMENTS (m,kN,kNm) ------------------------------- (*=Maximum, #=Minimum) Memb 12, Case 1 (Non-linear): Non-linear (Small, Sec, Resid): P-, P-, 2 Itns, 99.963% Cnv (Def gov) Station Location 0.000 3.231 6.462 9.693 12.924 16.155 19.387 22.618 25.849 29.080 32.311

812

Axial Force

Y-Axis Shear

Z-Axis Shear

X-Axis Torsion

Y-Axis Moment

Z-Axis Moment

-1.560# -1.542 -1.524 -1.506 -1.487 -1.469 -1.451 -1.433 -1.415 -1.397 -1.379*

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Cable Analysis

The following catenary cable equation from Hibbeler (15) for a single catenary element can be used to verify the results for member 12 shown above. As you can see, it was necessary to resolve the UDL to the local axis of the member (multiplying it by the cosine of the angle between the vertical). From this point the solution is straightforward, the result varying by only 0.3% (ie. 1.469kN vs. 1.465kN).

See also Members. See also Cable members.

813

Converting Old Jobs Converting old jobs SPACE GASS automatically converts all version 4.0 and newer jobs into the correct format at the time they are opened. They are then saved with the usual .SG naming convention. However, pre-version 4.0 jobs use multiple data files for each job, each of which has a filename extension of "DAT". In order to open the pre-version 4.0 files with the current version of SPACE GASS they must first be renamed to the new convention. This can be done automatically with a batch program called SGName.BAT that is supplied with SPACE GASS. In order to rename the old data files, you should first open a command (or DOS) prompt window, go to the folder containing the old data files and then run SGName from your SPACE GASS program folder. Assuming that the old files are in a folder called C:\OldData and the SPACE GASS program files are in a folder called C:\Program Files\SPACE GASS\EXE, the commands necessary to rename them are: C: CD\OldData C:\”Program Files"\”SPACE GASS"\EXE\SGName Once the files have been renamed, you can access them from the current version of SPACE GASS as normal. Naturally, they still have to be converted to the latest format, however this is done automatically as each job is opened by SPACE GASS.

815

Bibliography Bibliography 1. Harrison H.B. "Computer Methods in Structural Analysis", pp 248-251, Prentice Hall, 1973.

2. Ghali A. and Neville A.M. "Structural Analysis A Unified Classical and Matrix Approach", 2nd edition, pp 364-374, Chapman and Hall, London, 1978.

3. AS1250 - 1981 "SAA Steel Structures Code", Standards Australia, 1 The Crescent, Homebush, NSW, 2140, Australia.

4. AS4100 - 1998 "Steel Structures", Standards Australia, 1 The Crescent, Homebush, NSW, 2140, Australia.

5. SABS0162 - 1984 "Code of Practice for The Structural Use of Steel", The Council of the South African Bureau of Standards, Private Bag X191, Pretoria, Republic of South Africa.

6. BS5950 : Part 1 : 2000 "Structural Use of Steelwork in Building", British Standards Institution, 389 Chiswick High Road, London, W4 4AL.

7. NZS3404 - 1997 "Steel Structures Standard", Standards New Zealand, Wellington Trade Centre, Victoria Street, Wellington 1, New Zealand.

8. Clarke A.B. and Coverman S.H. "Structural Steelwork: Limit state design", p 49, Chapman and Hall, London, 1987.

9. Woolcock S.T., Kitipornchai S. and Bradford M.A. "Limit State Design of Portal Frame Buildings", 1st edition, AISC, 1991.

10. Clough R.W. and Penzien J. "Dynamics of Structures", McGraw-Hill Book Company, 1975.

11. AS3990 - 1993 "Mechanical equipment - Steelwork", Standards Australia, 1 The Crescent, Homebush, NSW, 2140, Australia.

12. Wittrick W.H. and Williams F.W. "Natural Frequencies of Elastic Structures", Quarterly Journal of Mechanics and Applied Mathematics, Vol. XXIV, Pt. 3, 1971.

817


13. AS/NZS4600 - 2005 "Cold-Formed Steel Structures", Standards Australia, 1 The Crescent, Homebush, NSW, 2140, Australia.

14. AS3600 - 2009 "Concrete Structures", Standards Australia, 1 The Crescent, Homebush, NSW, 2140, Australia.

15. Hibbeler R.C. "Engineering Mechanics", 6th edition, Macmillan Publishing Company, 1992.

16. AISC-ASD "Specification for Structural Steel Buildings, Allowable Stress Design", American Institute of Steel Construction (AISC), June 1, 1989.

17. AISC-LRFD "Load and Resistance Factor Design Specification for Structural Steel Buildings", American Institute of Steel Construction (AISC), Dec 1, 1993.

18. Eurocode 3 "Design of Steel Structures", European Committee for Standardization (CEN), DD ENV 1993-1-1 : 2005.

19. Tessler, A. and Hughes, T.J.R., "A three-node Mindlin plate element with improved transverse shear", Computer Methods In Applied Mechanics And Engineering 50 (1985) pp 71-101

20. Tessler, A. and Hughes, T.J.R., "An improved treatment of transverse shear in the Mindlin-type four-node quadrilateral element", Computer Methods In Applied Mechanics And Engineering 39 (1983) pp 311-335

21. Liu,, J, Riggs, H.R. and Tessler, A. , "A four-node, shear-deformable shell element developed via explicit Kirchoff constraints", International Journal For Numerical Methods In Engineering, Vol. 2000, 49, pp 1065-1086

22. Batoz, J., "An explicit formulation for an efficient triangular plate-bending element", International Journal For Numerical Methods In Engineering, Vol. 18 (1982), pp 1077-1089

23. Batoz, J. and Tahar, M.B., "Evaluation of a new quadrilateral thin plate", International Journal For Numerical Methods In Engineering, Vol. 18 (1982), pp 1655-1677

24. Hancock Gregory J., "Elastic method of analysis of rigid jointed frames including second order effects", Steel Construction, Vol. 28, No. 3, September 19947

818

Bibliography 25. Hong Kong Building Department, "Code of Practice for the Structural Use of Steel 2011", Buildings Department 12/F-18/F Pioneer Centre, 750 Nathan Road, Mongkok, Kowloon, Hong Kong

26. AISC 360-10, "Specification for Structural Steel Buildings", American Institute of Steel Construction (AISC), June 22, 2010

819

Index 2 2nd order analysis ................................. 484 See non-linear analysis ..................... 484 3 3D renderer ................................... 246, 458 A A quick frontwidth calculation method 492 Absolute coordinates .................... 295, 323 Acceleration.......................................... 168 Align members ..................................... 276 Aligning plate axes ............................... 278 Alignment ..................................... 148, 285 Amplitude ............................................. 444 Analysis ................................................ 475 Buckling analysis ............. 502, 506, 508 Dynamic frequency analysis .... 514, 516 Dynamic response analysis ...... 522, 524 Static analysis ........................... 476, 494 Warnings and errors ......................... 531 Angle sections ...................... 132, 145, 547 Animation ............................................. 445 Annotation .................................... 448, 625 Aperture circle ........................ 29, 269, 283 Arc generation ...................................... 279 Area loads ..................................... 179, 280 Area of section...................................... 132 Attach ........................... 246, 269, 283, 285 Attachments .......................................... 116 Auto scaling of base shear .................... 524 AutoCAD.............................. 77, 79, 81, 94 Axes ...................................................... 102 Global axes ....................... 102, 107, 447 Local axes ......................... 102, 107, 453 Local axes for moments and shears ... 29, 312 Axial force distribution......................... 508 Axial forces .......................................... 478 Described.......................................... 478 Diagrams .......................................... 444 Sign convention ................................ 107 Axis limits ............................................ 312 B Bar anchorage ....................................... 656 Base shear factor................................... 524 Bending effective lengths ..................... 547 Bending moments ................................. 478 Described.......................................... 478

Diagrams.....................................29, 444 Sign convention ............................... 107 Bends ................................................... 289 Bentley Structural .......................77, 79, 81 Bibliography ........................................ 817 Bill of materials ............................501, 773 BIM ...................................................77, 79 Bolts ......................623, 625, 636, 719, 728 Boundary conditions ............................ 129 See node restraints ........................... 129 Bracing..........................................223, 226 BS5950-1 2000 code specific items .... 600 Buckling analysis ................................. 475 Analysis ....................475, 485, 502, 508 Axial force distribution.................... 508 Cables .............................................. 506 Effective lengths .............................. 504 Load cases ....................................... 508 Load factor........................502, 506, 508 Messages.......................................... 494 Mode shapes .....................443, 502, 508 Node restraints ................................. 506 Results ......................................512, 776 Special considerations ..................... 506 C Cables .................................................. 475 Analysis ............................475, 482, 484 Buckling analysis............................. 506 Chord length .................................... 119 Convergence .................................... 482 Converted to tension-only ............... 119 Damping ...................................482, 494 Fixity.........................................119, 482 Length .............................................. 119 Load stepping ...........................482, 494 Loading .....................160, 164, 168, 482 Members ...................................119, 482 Worked example .............................. 805 CAD ..................................................77, 79 CAD interface module ........................... 94 Calculator............................................... 26 Cartesian coordinates ....................295, 323 Catenary cables .................................... 482 See cables ........................................ 482 Centre of gravity ...........................501, 773 Changing the appearance of SPACE GASS ............................................33, 34 Characteristic concrete strength ........... 146 Check boxes ........................................... 60 Chord length ........................................ 119 821

SPACE GASS 12 User Manual CIMSteel/2 file ........................... 77, 79, 81 CIS/2 file ................................................ 81 See CIMSteel/2 file ................ 77, 79, 81 Clean-up job ........................................... 68 Cleats .................................... 623, 625, 636 Click ....................................................... 57 Code check ........................................... 569 Codes .................................................... 562 Flange restraint ......................... 547, 562 Master-slave constraint..................... 148 Member fixity ................................... 119 Node restraint ................................... 129 Coefficient of thermal expansion ......... 146 Colors ............................................... 33, 34 Column and beam Tees ................ 144, 568 Combination load cases ........................ 169 Described.......................................... 169 Graphics ........................................... 290 Managing load cases ........................ 328 Text................................................... 206 Combined stress ratio ........................... 569 Limit ................................................. 569 Steel member design ........................ 569 Combo boxes .......................................... 60 Command buttons................................... 60 Command line options............................ 51 Compression effective lengths ..... 504, 547 Compression-only members 119, 481, 494, 516 Concrete beam design........................... 647 Described.......................................... 647 Designing and checking ........... 653, 664 Drawings .......................................... 662 Exporting .......................................... 664 Importing .......................................... 664 Input ................................................. 649 Load cases ................................ 649, 664 Minimum design actions .................. 654 Moment redistribution ...................... 657 Preferences ....................................... 669 Reports ..................................... 649, 664 Concrete column design ....................... 677 Biaxial bending ................................ 682 Confinement region .......................... 691 Described.......................................... 677 Designing and checking ........... 681, 693 Effective lengths ............................... 684 Exporting .......................................... 693 Importing .......................................... 693 Input ................................................. 679 Interaction diagrams ......................... 688 Load cases ................................ 679, 693 Minimum design actions .................. 683 Moment magnifiers .......................... 683 Preferences ....................................... 698 822

Reinforcement ................................. 684 Reports......................................679, 693 Voids................................................ 691 Configuring SPACE GASS ..............25, 36 Configuring the renderer........................ 36 Connect ................................................ 293 Connection design ............................... 623 Connectivity check .............................. 294 Constraint code .................................... 148 Context sensitive cursors ..................... 269 Continuous lateral restraint .................. 562 Contours............................................... 458 Control Panel ......................................... 34 Convergence 481, 482, 484, 494, 516, 569, 575, 717 Converting old jobs.............................. 815 Coordinate systems .............................. 102 Coordinates .......................................... 295 Absolute....................................295, 323 Cartesian ...................................295, 323 Polar..........................................295, 323 Relative .....................................295, 323 Copying ............................................... 328 Load cases ....................................... 328 Member loads .................................. 299 Member properties........................... 300 Node loads ....................................... 301 Node properties ............................... 302 Nodes, members or plates................ 296 Plate loads........................................ 303 Plate properties ................................ 304 Steel member properties .................. 546 Correction factors .................................. 32 CQC ..................................................... 524 Creating a new job ................................. 62 Critical flange ...................................... 582 Crosshair cursor ......................29, 380, 423 Crossing window ................................. 269 CSV file ............................................77, 79 Currents ........................................181, 411 Curved line resolution............................ 29 Custom libraries ................................... 721 Customizing Property panels .................................. 45 Toolbars ............................................. 42 D Damping .............................................. 174 Spectral curves................................. 174 Static analysis ...........................482, 494 Dashed lines ........................................... 29 Data entry .............................................. 60 Datasheet input .................................... 237 Dead loads ........................................... 230

Index Deleting .................................................. 67 Jobs ..................................................... 67 Load cases ........................................ 328 Parts of the structure ................. 269, 305 Design ................................................... 535 Combined stress ratio Steel member design............. 535, 592 Convergence ..................................... 535 Design groups and intermediate stations ...................................................... 578 Design segment535, 579, 580, 585, 586, 587, 592, 595 Lateral rotation factor ....................... 587 Load cases ................................ 535, 592 Load factor Steel member design............. 535, 592 Load height factor ............................ 586 Member segment ..... 535, 579, 580, 585, 586, 587, 592, 595 Moment magnification ..................... 535 Section check.................................... 580 Segment ... 535, 579, 580, 585, 586, 587, 592, 595 Steel connection design Design actions .............................. 641 Design procedure .......................... 641 Minimum design actions ...... 625, 636 Steel member design Assumptions ................................. 595 Check mode .................................. 595 Combined stress ratio ........... 535, 592 Described ...................................... 535 Design mode ................................. 595 Load factor............................ 535, 592 Section check ................................ 580 Segment535, 579, 580, 585, 586, 587, 592, 595 Stress ratio ................................ 535, 592 Torsional effects ............................... 535 Twist factor ...................................... 585 Development lengths ............................ 656 Diagram shading..................................... 29 Diagrams ...................................... 444, 458 Dialogue boxes ....................................... 58 Closing ............................................... 58 Moving ............................................... 58 Using the keyboard............................. 58 Dimensions ........................................... 332 Direction ............................................... 119 Angle ................................................ 119 Axis .................................................. 119 Node ................................................. 119 Vector ............................................... 174 Displacements ...................................... 478 Described.......................................... 478

Diagrams.......................................... 444 Sign convention ............................... 107 DOC file ................................................ 79 See MS-Word .................................... 79 Dongle ................................................... 11 See Hardware lock ........................11, 23 Doppler effect ...................................... 411 Double-click .......................................... 57 Drag ....................................................... 57 Draw .................................................... 306 DXF file ................................................. 94 Files ............................77, 79, 94, 95, 96 Layer names....................................... 29 Dynamic frequency analysis 172, 475, 514, 516 Frequency shift ................................ 516 Iterations .......................................... 516 Load cases ....................................... 516 Mode shapes ....174, 445, 514, 515, 516, 524 Natural frequencies .......................... 516 Results ......................................521, 774 Self mass.......................................... 516 Stiffness matrix ................................ 494 Worked example .............................. 735 Dynamic spectral response analysis ... 475, 522 Auto scaling of base shear ............... 524 Base shear factor.............................. 524 Load cases ....................................... 524 Mode combination method .............. 524 Results ..............................528, 529, 775 Sign of the results ............................ 524 Site factor......................................... 524 Site subsoil category ........................ 524 Spectral curve multiplier ................. 524 Vertical direction ............................. 524 Worked example .............................. 735 E Eccentric effects............................547, 569 Compression members .................... 590 Tension members............................. 591 Edit mode ......................................343, 374 Effective lengths Bending effective lengths ................ 550 Buckling analysis............................. 504 Compression effective lengths..504, 549 Concrete column effective length .... 684 Steel member effective lengths504, 549, 550 Eigenvalue ....................................502, 514 Eigenvector ...................................502, 514 Elastic critical buckling analysis ......... 502

823

SPACE GASS 12 User Manual See buckling analysis ....................... 502 Elastic critical load analysis ................. 502 See buckling analysis ....................... 502 Elastic restraints.................................... 129 See node restraints ............................ 129 Elastic suppprts..................................... 129 See node restraints ............................ 129 End fixity .............................................. 482 See member fixity .................... 119, 482 End moment ratios and other factors .... 589 Enveloping............................................ 446 Graphics ........................................... 446 Reports ............................................. 705 Errors .................................................... 531 Analysis ............................................ 531 Steel member design ........................ 620 Text file ............................................ 213 ETABS ................................................... 79 Euler buckling capacity 485, 494, 502, 504 Examples .............................................. 805 Cable analysis ................................... 805 Portal frame analysis ........................ 735 Portal frame connection design ........ 787 Portal frame member design............. 779 Exporting CIMSteel/2 file ............................. 79, 81 CIS/2 file ...................................... 79, 81 CSV file ................................ 79, 81, 636 DWG file .......................................... 636 DXF file................................ 94, 96, 636 IFC file ......................................... 79, 81 MS-Access file ........................... 79, 636 MS-Excel file ............................. 79, 636 MS-Word file ............................. 79, 636 SDNF file ........................................... 79 Step file ........................................ 79, 81 Text file .............................. 79, 185, 636 ZIP file................................................ 79 Extend members ................................... 309 Extrude members .................................. 310 F Filters .............................................. 74, 312 Find....................................................... 314 Fixity .................................................... 119 See members .................................... 119 Flange restraints.................... 547, 562, 583 Flexural-torsional buckling .................. 502 Flipping a section ......................... 132, 143 Floor loading ........................................ 280 See area loading ............................... 280 Floor slab .............................................. 148 Folders .................................................... 26 Fonts ..................................................... 705

824

See output ........................................ 705 Forces................................................... 478 Described ......................................... 478 Diagrams.......................................... 444 Sign convention ............................... 107 Frame data ........................................... 113 Frame imperfections ............................ 569 See Imperfections ............................ 569 Frameworks Plus ..................77, 79, 81, 94 Frequency ............................................ 444 Frequency shift .................................... 516 Frontwidth ............................486, 491, 492 Full restraint ......................................... 562 G Gauge ................................................... 625 General colours ...................................... 34 General configuration ............................ 29 General restraint................................... 129 Generate arc ......................................... 279 Geometry and loads ............................. 736 Girts ..................................................... 223 Global axes ...........................102, 107, 447 Graphical input Colors ................................................ 33 Cursor .............................................. 269 Dimensions ........................................ 32 Display area ....................................... 53 Editing ......................................246, 269 Input ..........................................246, 269 Output .......................................705, 716 Overview ......................................... 269 Text format ........................................ 28 Gravity ................................................. 168 Grid ...............................................246, 317 Gridlines .............................................. 319 Group code ...................................547, 725 H Hardware lock...................................11, 24 Haunches ......................431, 623, 625, 636 Headings .............................................. 116 Heartbeat ................................................ 24 Hong Kong CP2011 code specific items ......................................................... 605 Horizontal angle................................... 468 HTML file............................................ 709 Page setup ........................................ 709 Print preview ................................... 713 I IFC file........................................77, 79, 81 Ill-conditioning and instabilities .......... 111

Index Imperfections ........................................ 569 Importing ................................................ 79 ARC file ............................................. 79 CIMSteel/2 file ............................. 79, 81 CIS/2 file ...................................... 79, 81 CSV file ........................................ 79, 81 DXF file........................................ 94, 96 IFC file ......................................... 79, 81 Microstran file .................................... 79 MS-Access file ........................... 79, 636 MS-Excel file ............................. 79, 636 SDNF file ........................................... 79 Spectral curve text file ...................... 178 Step file ........................................ 79, 81 Text file ...................................... 79, 185 ZIP file................................................ 79 Incremental displacements ................... 494 Infotips.................................................. 321 Initiator ................................................. 187 Input methods ......................................... 77 Instabilities ................................... 111, 502 Installing SPACE GASS ........................ 24 Intermediate member stations....... 569, 578 Intermediate nodes................ 351, 400, 401 Moving intermediate nodes .............. 351 Removing crossed member nodes .... 400 Removing intermediate nodes .......... 401 Intersect ........................................ 293, 322 Iterating the analysis-design process .... 575 J Jobs ......................................................... 68 Attachments ...................................... 116 Clean-up ............................................. 68 Delete ................................................. 67 Merge ................................................. 65 New .................................................... 63 Open ................................................... 64 Save .................................................... 66 Status .................................... 55, 73, 717 K Keyboard .............................................. 295 Input ......................................... 295, 323 Shortcuts ............................................. 74 Kt factor ................................................ 569 L Labelling and annotation ...................... 448 Lateral restraint..................................... 562 See flange restraints.......................... 562 Legal notice .............................................. 6 Libraries.................................................. 81

Converting section names when importing or exporting................... 81 Creating custom libraries ................. 721 Standard libraries ............................. 719 The library editor ............................. 721 Library scan code..........................547, 725 Licence Agreement .................................. 6 Lift off.................................................. 119 Line width .............................................. 32 Linear analysis ..............101, 475, 476, 494 Linking to other programs ..................... 79 List boxes ............................................... 60 Lists ....................................................... 60 Live loads ............................................ 230 Load cases...... 74, 101, 174, 237, 476, 484, 494, 508, 514, 516, 524, 569, 578, 625, 636 Combining ........................169, 206, 290 Copying ........................................... 328 Deleting ........................................... 328 Load case titles viewer .................... 451 Manage ............................................ 328 Renumbering ................................... 328 Scrolling ............................................ 74 Titles ................................................ 171 Titles text ......................................... 207 Load factor ........................................... 502 Buckling analysis..............502, 506, 508 Limit .........................................508, 569 Steel member design.................569, 593 Load height factor ................................ 586 Load height position .............547, 557, 586 Load stepping ...............................482, 494 Loading diagrams ................................ 444 Loads ................................................... 299 Copying member loads .................... 299 Copying node loads ......................... 301 Copying plate loads ......................... 303 Filtering loads .................................. 312 See area loads .................................. 179 See combination load cases ............. 169 See load case titles ........................... 171 See lumped masses .......................... 172 See member concentrated loads ...... 158 See member distributed forces ........ 160 See member distributed torsions...... 162 See moving loads ............................. 352 See node loads ................................. 156 See plate pressure loads ................... 167 See prescribed node displacements . 157 See prestress loads ........................... 164 See sea loads .............................181, 411 See self weight ................................. 168 See spectral loads ............................ 174 See thermal loads ............................. 164 825

SPACE GASS 12 User Manual Local axes ............................. 102, 107, 453 Local axes for moments and shears 29, 312 Logo................................................ 47, 709 Lumped masses .................................... 172 Converting static loads to masses ..... 426 Described.......................................... 172 Dynamic frequency analysis ............ 516 Graphics ................................... 326, 444 Text................................................... 208 M Macros .................................................... 69 Margins................................................. 709 See page setup .................................. 709 Mass density ......................................... 146 Masses .................................................. 172 See lumped masses ........................... 172 Master node .......................................... 148 Master-slave constraints ....................... 148 Described.......................................... 148 Graphics ........................................... 330 Text................................................... 195 Material properties................................ 146 Described.......................................... 146 Graphics ........................................... 331 Library ...................................... 719, 727 Text................................................... 194 MDB file................................................. 77 See MS-Access ............................. 77, 79 Measure ................................................ 332 Member alignment........................ 148, 154 Member check .............................. 581, 593 Member concentrated loads .................. 158 Described.......................................... 158 Graphics ................................... 334, 444 Text................................................... 199 Member distributed forces .................... 160 Described.......................................... 160 Graphics ................................... 336, 444 Text................................................... 200 Member distributed torsions ................. 162 Described.......................................... 162 Graphics ................................... 338, 444 Text................................................... 201 Member groups..................................... 558 Member imperfections.......................... 569 See Imperfections ............................. 569 Member numbering .............. 402, 491, 493 Member offsets ..................................... 154 Described.......................................... 154 Graphics ........................................... 340 Text................................................... 196 Member origins .................................... 455 Member prestress loads ........................ 341

826

Described ......................................... 165 Graphics....................................341, 444 Text .................................................. 203 Member schedule ................................... 94 Members .............................................. 119 Described ..........................101, 107, 119 Graphics........................................... 343 Text .................................................. 190 Menu system .......................................... 53 Merging jobs .......................................... 65 Meshing ............................................... 346 Microsoft ............................................... 77 Access ...........................................77, 79 Excel .............................................77, 79 Windows ............................................ 62 Word .................................................. 79 Microstation ..........................77, 79, 81, 94 Microstran .........................................77, 79 Minimum design actions......631, 636, 654, 683 Mirror................................................... 348 Mode combination method .................. 524 Mode shapes ........................................ 502 Buckling analysis......443, 502, 506, 508 Dynamic frequency analysis ... 445, 514, 515, 516 Dynamic response analysis ..... 174, 522, 524 Viewing mode shapes ...............443, 445 Modelling considerations..................... 515 Modulus of subgrade reaction ............. 129 Moment of inertia ................................ 132 Moment redistribution ......................... 657 Moments .............................................. 478 Described ......................................... 478 Diagrams.......................................... 444 Sign convention ............................... 107 Mouse .................................................... 74 The mousewheel ................................ 74 Using the mouse ................................ 57 Move .................................................... 349 Moving intermediate nodes ................. 351 Moving loads ........................182, 352, 733 MS-Access ......................79, 238, 312, 721 MS-Excel ..................77, 79, 238, 312, 721 MS-Word ........................79, 238, 312, 721 Multiple viewports ............................... 370 Multiplying factor ................................ 169 Multi-row editing ................................. 238 N Natural frequencies ...............172, 514, 516 New features .......................................... 12 Node loads ........................................... 156

Index Described.......................................... 156 Graphics ........................................... 372 Text................................................... 197 Node numbering ................... 402, 491, 493 Node restraints ...................... 101, 129, 377 Buckling analysis ............................. 506 Described.......................................... 129 Elastic restraint ................................. 129 Frame data ........................................ 129 General restraint ............................... 129 Graphics ........................................... 377 Restraint code ................................... 129 Text................................................... 192 Nodes .................................................... 101 Described.................................. 101, 118 Graphics ........................................... 374 Text................................................... 189 Non-linear analysis ...... 101, 475, 476, 479, 480, 482, 484, 494 Normal members .................................. 119 Normal window .................................... 269 Normalize mode shapes ........................ 516 Notes..................................................... 378 O Ocean currents .............................. 181, 411 Offsets .................................................. 154 See member offsets .......................... 154 See plates .......................................... 124 Opening a job ......................................... 62 Operating plane .................................... 382 Optimization . 475, 486, 491, 492, 493, 494 Ortho............................................. 285, 380 Output ................................................... 512 Buckling analysis ............................. 512 Described.......................................... 705 Dynamic frequency analysis ............ 521 Dynamic response analysis .............. 529 Fonts ................................................... 28 Page setup......................................... 709 Print graphics.................................... 716 Print preview .................................... 713 Print text report................................. 715 Printing this manual ............................. 5 Printing to a file ........................ 709, 713 Scale ......................................... 709, 716 Static analysis ................................... 501 Status report...................................... 717 Steel connection design .................... 643 Steel member design ........................ 593 Text format ......................................... 28 Worked examples ............. 735, 779, 805

P Page setup ............................................ 709 Pan ....................................................... 381 Paradise solver ......................494, 508, 516 Partial restraint ..................................... 562 P-delta effects ...............479, 480, 484, 494 PDF file.........................................709, 713 PDF manual ............................................. 5 Pick .................................................57, 269 Picture file............................................ 709 Page setup ........................................ 709 Print preview ................................... 713 Pitch ..................................................... 625 Plane .............................................246, 382 Plate pressure loads.............................. 167 Described ......................................... 167 Graphics............................384, 439, 444 Text .................................................. 204 Plates.................................................... 278 Align plate axes ............................... 278 Contours .......................................... 458 Datasheet ......................................... 238 Described ..........................101, 107, 124 Drawing ........................................... 306 Graphics....................................386, 458 Library ......................................719, 729 Meshing ........................................... 346 Moments for reinforced concrete slabs ..................................................... 107 Pressure loads ...................167, 384, 439 Reverse plate direction .................... 406 Steel connection design ...623, 625, 636, 719, 729 Stress................................................ 458 Text .................................................. 191 Wood-Armer method....................... 107 Point ....................................................... 57 Pointer.................................................... 57 Poisson's ratio ...................................... 146 Polar coordinates ..........................295, 323 Portal frame builder ............................. 221 Prescribed node displacements ............ 157 Described ......................................... 157 Graphics....................................389, 444 Text .................................................. 198 Pressure................................................ 167 See area loads .................................. 280 See plate pressure .............167, 384, 439 Prestress ............................................... 165 See member prestress loads ............. 165 Pre-tension ........................................... 164 Principal angle ..................................... 132 Print preview........................................ 713 See output ........................................ 705

827

SPACE GASS 12 User Manual Printing ................................................. 705 See output ......................................... 705 Problem size limits ................................. 35 Program Manager ................................... 24 Property panels ..................................... 391 ProSteel ...................................... 77, 79, 81 Purlins................................................... 223

Rigid offset .......................................... 154 Risa-3D .................................................. 79 ROBOT .................................................. 79 Rotate ................................................... 407 Rotational inertia ................................. 172 Rotational restraint............................... 562 S

Q Query Analysis results ................................ 395 Member properties ........................... 343 Node properties ................................ 374 R Radio buttons .......................................... 60 Rational buckling analysis .................... 502 See buckling analysis ....................... 502 Reactions .............................................. 478 Described.......................................... 478 Diagrams .......................................... 444 Sign convention ................................ 107 Real-time .............................................. 468 Redraw.................................................. 399 Region .................................................. 230 Registering SPACE GASS ............... 24, 47 Reinforcement ...... 107, 647, 677, 719, 731 Relative coordinates ..................... 295, 323 Removing crossed member nodes ........ 400 Removing intermediate nodes .............. 401 Renderer ........... 36, 42, 246, 285, 391, 458 Renumbering ........................................ 328 Load cases ........................................ 328 Members ........................................... 402 Nodes................................................ 402 Repeat last command ............................ 404 Reports.................................................. 705 See output ......................................... 705 Residual loading ................................... 494 Restraints .............................................. 129 See node restraints ............................ 129 Results .................................................. 512 Buckling analysis ............................. 512 Dynamic frequency analysis ............ 521 Dynamic response analysis .............. 529 Static analysis ................................... 501 Steel connection design .................... 643 Steel member design ........................ 593 Reverse member direction .................... 405 Reverse plate direction ......................... 406 Revit Structure ...................... 77, 79, 81, 91 Right hand orthogonal .......................... 102 Right hand screw rule ........................... 107 Rigid diaphram ..................................... 148 828

SAP2000 ................................................ 79 Saving a job ........................................... 62 Scale..................................................... 408 Scales ................................................... 409 Scissor lift ............................................ 148 Scripts .................................................... 70 Scroll bars .............................................. 60 Scrolling................................................. 74 SDNF file ..........................................77, 79 Sea loads .......................................181, 411 Seats ......................................623, 625, 636 Secant matrix ....................................... 494 Section check ....................................... 593 Section properties .................101, 119, 418 Angle sections ..........................132, 145 Area of section ................................. 132 Described ......................................... 132 Flipping a section .....................132, 143 Graphics........................................... 418 Library ......................................719, 725 Map file ............................................. 81 Moment of inertia ............................ 132 Principal angle ................................. 132 Section mark .................................... 132 Shape builder ................................... 136 Shear area ........................................ 132 Source .............................................. 132 Tee sections ..................................... 144 Text .................................................. 193 Torsion constant .............................. 132 Security .................................................. 11 See Hardware lock ........................11, 23 Seismic Dynamic spectral response analysis 522 Indian seismic checks ...................... 547 New Zealand seismic checks ........... 547 Selecting nodes and members .............. 269 Selection window................................. 269 Self mass .......................................172, 516 Self weight ........................................... 168 Described ......................................... 168 Graphics....................................422, 444 Text .................................................. 205 Sentinel protection installer ................... 24 Serviceability check ............................. 576 SG file .................................................... 62

Index SG.INI .................................................... 25 Shading ................................................... 29 Shape builder ........................ 132, 136, 343 Shear area ............................................. 132 Shear check........................................... 593 Shear forces .......................................... 478 Described.......................................... 478 Diagrams .......................................... 444 Sign convention ................................ 107 Shear wall ............................................. 148 Shielding............................................... 230 Shortcuts ................................................. 74 Sidesway............................................... 547 Sign conventions .................................. 107 Analysis ............................................ 107 Bending moment diagrams ................. 29 Steel member design ........................ 557 Sign of the results ................................. 524 Site factor ............................................. 524 Site subsoil category ............................. 524 Skew angle ........................................... 119 See direction angle ................... 119, 124 Slave node ............................................ 148 Slenderness ratio................................... 569 SmartPlant4D ......................................... 79 Snap .............................................. 246, 423 Solvers Paradise ............................ 494, 508, 516 Watcom ............................ 494, 508, 516 Wavefront ......................... 494, 508, 516 Sound ...................................................... 29 Spectral loads ....................................... 174 Described.......................................... 174 Editor ................................................ 177 Library ...................................... 719, 732 Spectral curve multiplier .................. 524 Text................................................... 209 Spring stiffness ..................................... 129 SRSS..................................................... 524 STAAD................................................... 79 Stability analysis................................... 502 See buckling analysis ....................... 502 Stabilizing nodes .......................... 111, 494 Standard shapes .................................... 343 Starting SPACE GASS ........................... 50 Static analysis ....................... 475, 476, 494 Analysis type .................................... 494 Buckling ........................................... 485 Buckling messages ........................... 494 Compression-only members ............. 494 Damping ................................... 482, 494 Errors ................................................ 531 Iterations per load step ..................... 494 Load cases ........................................ 494 Load stepping ........................... 482, 494

Non-linear effects ............................ 494 Optimization .................................... 494 Results ..............................501, 755, 766 Tension-only members .................... 494 Worked example .............................. 735 Static load to mass conversion ............. 426 Status line .............................................. 55 Status report ....................................73, 717 Steel connection design ....................... 623 Described ......................................... 623 Designing and checking................... 636 Drawings...................................625, 636 Exporting ..................................625, 636 Importing ......................................... 636 Input ................................................. 625 Load cases ................................625, 636 Minimum design actions ..........625, 636 Preferences ...................................... 645 Reports............................................. 643 Steel member design ............................ 577 Check mode ..................................... 577 Combined stress ratio ...................... 569 Described ..................................543, 547 Design mode .............................569, 577 Effective lengths .......................504, 547 Errors ............................................... 620 Flange restraints............................... 562 Grouping ...........................547, 558, 578 Input ..................537, 538, 543, 545, 546 Load cases ....................................... 569 Load factor....................................... 569 Member check ................................. 593 Results ......................................593, 784 Section check ................................... 593 Shear check...................................... 593 Sign convention ............................... 557 Tee sections ..................................... 568 Text .................................................. 210 Worked example .............................. 779 Step file .......................................77, 79, 81 CIMSteel/2 file .......................77, 79, 81 IFC file....................................77, 79, 81 Stiffeners ...............................623, 625, 636 Stiffness matrix ....101, 111, 491, 493, 494, 516 Strength grade ...................................... 547 Stress ratio ........................................... 569 Stresses .........................................444, 458 Members .......................................... 444 Plates................................................ 458 Stretch .................................................. 427 StruCAD .....................................77, 79, 81 Structure wizard ................................... 219 Sub load number ...................158, 160, 162 Subdivide ............................................. 428 829

SPACE GASS 12 User Manual Subsets .................................................. 312 See filters .......................................... 312 Supports ................................................ 129 See node restraints ............................ 129 T Tangent matrix ..................................... 494 Tapered members ................................. 431 Tapered plates....................................... 429 Tee sections .......................... 144, 568, 725 Tekla Structures .......................... 77, 79, 81 Temperature change ............................. 164 Tension-only and compression-only effects ............................................... 481 Tension-only members 119, 481, 482, 494, 516 Terminator ............................................ 212 Terrain category.................................... 230 Text boxes .............................................. 60 Text display area..................................... 53 Text editor ............................................ 185 Text file ................................................ 213 Errors ................................................ 213 Exporting .......................................... 185 Format ........................................ 28, 186 Importing .......................................... 185 Worked example .............................. 216 Text reports........................................... 705 See output ......................................... 705 Textures ................................................ 433 Thermal loads ....................................... 164 Described.......................................... 164 Graphics ................................... 435, 444 Text................................................... 202 Title bar .................................................. 53 Toolbars .................................................. 53 Customizing ....................................... 42 Top flange............................................. 543 Topography .......................................... 230 Torsion constant ................................... 132 Torsions ................................................ 478 Described.......................................... 478 Diagrams .......................................... 444 Sign convention ................................ 107 Translational inertia .............................. 172 Transparency ........................................ 437 Trapezoidal loads.................................. 160 Triangular loads .................................... 160 U Units ............................... 29, 114, 187, 725 Unstable equilibrium ............................ 485 Updating frame member sizes .............. 575 Using the keyboard to position points .. 323 830

Using the mouse .................................... 57 Utilization ratio .................................... 625 V Varying plate pressure loads ................ 439 Vehicle library ..............................352, 733 Vertical angle ....................................... 468 Vertical axis ..............................29, 41, 468 Vertical direction ................................. 524 View..................................................... 444 Diagrams.......................................... 444 Member properties........................... 456 Members .......................................... 457 Node properties ............................... 456 Nodes ............................................... 457 Plate contours .................................. 458 Steel connection drawings ............... 625 View manager ...................................... 454 View results ......................................... 705 See output ........................................ 705 View results in XY or XZ plane .......... 460 View selector ....................................... 468 Viewpoint ............................................ 468 Viewports............................................. 370 Views ..............................................74, 471 Voids.................................................... 691 Von Mises Stress ................................. 107 W WALF .................................................. 594 Watcom solver ......................494, 508, 516 Wave loads ...................................181, 411 Wavefront optimizer .............475, 486, 494 Analysis method .............................. 491 Analysis method in more detail ....... 493 Calculating the frontwidth ............... 492 Wavefront solver ..................494, 508, 516 Weighted average load factor .............. 594 Welcome to SPACE GASS ..................... 1 Welds ....................623, 625, 636, 719, 730 Wind loads ........................................... 230 Windows ................................................ 62 Wood-Armer Method .......................... 107 Worked examples ................................ 773 Bill of materials ............................... 773 Buckling analysis............................. 776 Cable analysis ...........................805, 808 Centre of gravity .............................. 773 Dynamic frequency analysis ............ 774 Dynamic response analysis .............. 775 Frame analysis graphics................... 743 Frame analysis input ........................ 747 Frame analysis output ...............755, 766 Portal frame analysis ....................... 735

Index Portal frame connection design ........ 787 Portal frame member design............. 779 Steel connection design .................... 623 Steel connection drawings ................ 625 Steel member design ........................ 784 Working plane .............................. 246, 382

XSteel .........................................77, 79, 81

X

ZIP file ................................................... 79 Zones ................................................... 655 Zoom.................................................... 473

XLS file .................................................. 77 See MS-Excel ............................... 77, 79

Y Young's modulus ................................. 146 Z

831

SPACE GASS 12.5 HELP MANUAL

Recommend Documents