DGS-1882-001-Structural Design Basis.pdf

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ABU DHABI GAS INDUSTRIES LTD. (GASCO) STRUCTURAL DESIGN BASIS

DESIGN GENERAL SPECIFICATION

STRUCTURAL STRUCTURAL DESIGN BASIS

5 4 3 2

1

13/03/2007

NAJEEB AL MASKARI PEM/C4

AYMAN A. KHALIK PED/D3

ROMESH KUMAR PED

SAEED Y. AL AMERI PE

UPDATED & REISSUED FOR IMPLEMENTATION

0

15/05/01

A. KHALIK

SHIREEN EL TAKI

-

ABDUL AZIZ AL AMERI

ISSUED FOR IMPLEMENTATION

A

13/11/99

A. KHALIK

SHIREEN EL TAKI

-

MOHAMMED A. SAHOO

ISSUED FOR COMMENTS

Rev.

Date DD/MM/YY

WRITTEN BY

CHECKED BY

ENDORSED BY

APPROVED BY

STATUS

DOCUMENT REVISIONS

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CONTENTS 1.

GENERAL GENERAL................ ............................... ............................... ................................ .............................. .............................. ................................ ................................ .......................... .......... 4 1.1

INTRODUCTION ............................... ............................................. .............................. ................................ ............................... ............................... ............................. ............. 4

1.2

PURPOSE ................................. ............................................... .............................. ................................ .............................. .............................. ................................ ................... ... 4

1.3

DEFINITIONS .............................. .............................................. ................................ ............................... ............................... ................................ .............................. ................ 4

2.

CODES AND STANDA STANDARDS.................... RDS.................................... .............................. .............................. ................................ ................................ .......................... .......... 5

3.

REFERENCE REFERENCE DOCUMENTS DOCUMENTS .............................. .............................................. ................................ ............................... ............................... ............................. ............. 8

4.

DOCUMENT DOCUMENT PRECEDENCE.................. PRECEDENCE.................................. .............................. .............................. ................................ .............................. ........................ .......... 10

5.

SPECIFICA SPECIFICATION TION DEVIATION DEVIATION/CONCE /CONCESSION SSION CONTROL CONTROL .............................. .............................................. ............................. ............. 10

6.

QUALITY QUALITY ASSURAN ASSURANCE/QU CE/QUALIT ALITY Y CONTROL CONTROL ............................... ............................................... ................................ ............................. ............. 11

7.

DESIGN DESIGN REQUIREMENTS........ REQUIREMENTS........................ ............................... ............................... ................................ .............................. .............................. ...................... ...... 11

8.

9.

7.1

REFERENCE CODES AND STANDARDS .............................. .............................................. ................................ .............................. ........................ .......... 11

7.2

MEASUREMENT .............................. ............................................ .............................. ................................ ............................... ............................... ........................... ........... 11

SITE SURVEY SURVEY AND SOILS REPORT............ REPORT............................ ................................ .............................. .............................. ................................ .................. 11 8.1

SITE SURVEY.............................. .............................................. ................................ ............................... ............................... ................................ ............................. ............. 11

8.2

SOILS REPORT ............................... ............................................. .............................. ................................ ............................... ............................... ........................... ........... 11

BASIC BAS IC DESIGN DESIGN AND DRAWING CONCEPTS CONCEPTS .............................. ............................................ .............................. ................................ .................. 12 9.1

DESIGN AND CALCULATIONS .............................. ............................................ .............................. ................................ ............................... ........................ ......... 12

9.2

DRAWINGS AND RELATED DOCUMENTS ............................ ............................................ ................................ .............................. ........................ .......... 13

9.3

STEEL STRUCTURES .............................. .............................................. .............................. .............................. ................................. ............................... .................. .... 17

9.4

REINFORCED CONCRETE STRUCTURES AND FOUNDATIONS ................................ ............................................... ........................ ......... 19

9.5

PROJECT CONSIDERATIONS FOR REINFORCED CONCRETE .............................. .............................................. ........................... ........... 22

9.6

CONCRETE MASONRY STRUCTURES .............................. .............................................. ............................... ............................... ........................... ........... 28

9.7

GROUTING ................................ .............................................. .............................. ................................ .............................. .............................. ................................ .................. 28

9.8

FIREPROOFING ............................... ............................................. .............................. ................................ ............................... ............................... ........................... ........... 28

10.

LOADS. LOADS. ............................ ............................................ ................................ ................................ ............................... ............................... ................................ ............................. ............. 28

11.

LOAD LOAD COMBINAT COMBINATIONS IONS .............................. .............................................. .............................. .............................. ................................. ............................... .................. .... 40

12.

STRUCTURA STRUCTURAL L MATERIA MATERIALS LS .............................. .............................................. ................................ ............................... ............................... ........................... ........... 42 12.1 GENERAL .............................. .............................................. ................................ .............................. ............................... ................................. .............................. .................. .... 42 12.2 STRUCTURAL STEEL .............................. .............................................. .............................. .............................. ................................. ............................... .................. .... 42 12.3 CAST-IN-PLACE CONCRETE .............................. ............................................ .............................. ................................ ............................... ........................ ......... 42 12.4 REINFORCING STEEL ............................. ............................................. .............................. .............................. ................................. ............................... .................. .... 42 12.5 CONCRETE MASONRY.............................. .............................................. ................................ .............................. .............................. ................................ .................. 42

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12.6 ANCHOR BOLTS ............................... ............................................... .............................. .............................. ................................ .............................. ........................ .......... 43 12.7 HANDRAIL ................................. ............................................... .............................. ................................ .............................. .............................. ................................ .................. 43 12.8 W ELDING .............................. .............................................. ................................ .............................. ............................... ................................. .............................. .................. .... 43 12.9 GRATING .............................. .............................................. ................................ .............................. ............................... ................................. .............................. .................. .... 43 12.10 FLOOR PLATE ............................... ............................................. .............................. ................................ ............................... ............................... ........................... ........... 43 12.11 BOLTS ............................ ............................................ ................................ .............................. .............................. ................................ ................................ ........................ ........ 43 12.12 GROUTING ............................... ............................................. .............................. ................................ .............................. .............................. ................................ .................. 43 12.13 EMBEDDED ITEMS............................... .............................................. ............................... ................................ .............................. .............................. ...................... ...... 44 13.

ALLOWA ALLOWABLE BLE STRESSES...... STRESSES...................... ................................ .............................. .............................. ................................ ................................ ........................ ........ 44 13.1 STRUCTURAL STEEL .............................. .............................................. .............................. .............................. ................................. ............................... .................. .... 44 13.2 CAST-IN-PLACE CONCRETE .............................. ............................................ .............................. ................................ ............................... ........................ ......... 44 13.3 MASONRY ................................. ............................................... .............................. ................................ .............................. .............................. ................................ .................. 44 13.4 ANCHOR BOLTS AND BASE PLATE BEARING .............................. ............................................ .............................. ................................ .................. 44 13.5 STRESS INCREASE .............................. ............................................. ............................... ................................ .............................. .............................. ...................... ...... 44

14.

DEFLECTIO DEFLECTION N AND VIBRATION VIBRATION .............................. .............................................. ................................ .............................. .............................. ...................... ...... 44 14.1 ALLOWABLE DEFLECTIONS ............................... ............................................. .............................. ................................ ............................... ........................ ......... 45 14.2 VIBRATION ................................ .............................................. .............................. ................................ .............................. .............................. ................................ .................. 46

15.

MISCELLAN MISCELLANEOUS EOUS DESIGN DESIGN DATA DATA ............................. ........................................... ............................... ................................. .............................. .................. .... 48 15.1 CLEARANCES AND ACCESSIBILITY ................................. ............................................... .............................. ................................ ............................. ............. 48 15.2 COEFFICIENTS OF STATIC FRICTION .............................. .............................................. ............................... ............................... ........................... ........... 49

16.

ENGINEERING ENGINEERING MAIN MAINTENA TENANCE NCE MANU MANUAL AL .............................. .............................................. .............................. .............................. ...................... ...... 49 16.1 DESIGN BASIS ................................ .............................................. .............................. ................................ ............................... ............................... ........................... ........... 49 16.2 INSPECTION .............................. ............................................ .............................. ................................ .............................. .............................. ................................ .................. 50 16.3 MATERIALS ............................... ............................................. .............................. ................................ .............................. .............................. ................................ .................. 50 16.4 MAINTENANCE AND REPAIR PROCEDURES ................................ .............................................. .............................. ................................ .................. 50 16.5 FINISHING MATERIAL MANUAL ................................ .............................................. .............................. ................................. ............................... .................. .... 50

17.

OPERATIONA OPERATIONAL L REQUIREMENT REQUIREMENTS S .............................. ............................................ ............................... ................................. .............................. .................. .... 50 17.1 CONCRETE ASSET MANAGEMENT SYSTEM (CAMS) (CAMS) ............................... ............................................. .............................. ...................... ...... 50 17.2 EXISTING SETTLEMENT CHECK SURVEY PROGRAM ................................ .............................................. .............................. ...................... ...... 50 17.3 CORROSION MONITORING SYSTEM FOR CRITICAL CONCRETE STRUCTURES ................................ .................................. 51

18.

UNITS OF MEASUREM MEASUREMENT............. ENT............................. ................................. ............................... .............................. ................................ ............................. ............. 51

19.

ATTACH ATTACHMENT MENTS S .............................. ............................................ .............................. ................................ .............................. .............................. ................................ .................. 51

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1.

GENERAL

1.1

INTRODUCTION This specification establishes the minimum criteria for structural engineering and design.

1.2

PURPOSE This specification contains the minimum criteria for structural engineering and design for the framework and foundations of all buildings, process structures and pipe racks and for the foundations for vertical vessels, horizontal vessels, heat exchangers, storage tanks and vibrating equipment, grade and elevated slabs and masonry structures. Miscellaneous plant structures such as pits, sumps and retaining walls are also covered by this criteria.

1.3

DEFINITIONS For the purpose of this specification, the f ollowing definitions shall apply: COMPANY

ABU DHABI GAS INDUSTRIES LTD. (GASCO) and its successors in interest and assignees.

CONTRACTOR

The party which carries out all or part of the design engineering, procurement, construction and commissioning or management of the project.

SUBCONTRACTOR

An organization providing specific services to the CONTRACTOR.

DESIGNER

The Engineering Division of the CONTRACTOR or the Consultant which performs the design of the element in question.

CONCESSION REQUEST

A deviation requested by the CONTRACTOR usually after receiving the contract package or purchase order. Often, it refers to an authorization to use, repair, recondition, reclaim or release materials, components or equipment already in progress or completely manufactured but does not meet with COMPANY requirements. A CONCESSION REQUEST is subject to PMT approval.

MANUFACTURER

The service organization which actually manufactures the material/product in question.

PROJECT:

(To be defined)

PROJECT MANAGEMENT

The COMPANY-authorized COMPANY-authorized party responsible for the

TEAM (PMT):

overall day-to-day execution of the Project. PMT is to serve as a liaison between COMPANY and the CONTRACTOR(S) on the Project.

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2.

SHALL:

Indicates a mandatory requirement.

SUPPLIER:

The organization which supplies the material/product to the CONTRACTOR/SUBCONTRACTOR.

CODES AND STANDARDS The following Codes, Standards and Specifications form a part of this specification. When an edition date is not indicated, the latest edition in force at the time of the contract award shall apply. Where there are conflicts between the requirements of different Codes and Standards the most stringent criteria shall apply. Alternate Codes, Standards and Specifications meeting the requirements of the referenced Codes, Standards and Specifications may be used with approval by the COMPANY. Steel grade material S 275 JR to BS EN 10025 and bolts to t o BS 4190 and BS 4395 may be used upon the COMPANY approval. Steel grade 43A to BS 4360 may be used for small access platforms without valves, small pipe supports, handling and ladders, subject to COMPANY approval. AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) ASSE/SAFE A1264.1 Safety Requirements for Floor and Wall Openings, Railings and Toeboards. ANSI A14.3

Safety Requirement for Fixed Ladders.

ASSA A1264 Requirements for Fixed Fixed Industrial Stairs AMERICAN SOCIETY OF CIVIL ENGINEERS (ASCE) ASCE 7

Minimum Design Loads for Buildings and other Structures

AMERICAN INSTITUTE OF STEEL CONSTRUCTION (AISC). AISC

Specification for Structural Steel Buildings

AISC

Manual of Steel Construction, 9th Edition

AISC

Code of Standard Practice for Steel Buildings and Bridges

AISC

Specification for Structural Joints Using ASTM A 325 or A 490 Bolts

AMERICAN CONCRETE INSTITUTE (ACI) ACI 301

Specifications for Structural Concrete for Buildings

ACI 302.1R

Guide for Concrete Floor and Slab Construction

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ACI 318M

Building Code Requirements for Reinforced Concrete Commentary on Building Code Requirements for Reinforced Concrete

ACI 325.3R

Guide for Design of Foundations and Shoulders for Concrete Pavements

ACI 336.2R

Suggested Analysis and Design Procedures for Combined Footings and Mats

ACI 350R

Environmental Engineering Concrete Structures

ACI 530

Building Code Requirements for Concrete Masonry Structures

AMERICAN WELDING SOCIETY (AWS) AWS

D1.1 Structural Welding Code - Steel

AWS

D1.4 Structural Welding Reinforcing Steel

AMERICAN PETROLEUM INSTITUTE (API) API 650

Appendix E, Tenth Edition

AMERICAN SOCIETY FOR NON-DESTRUCTIVE TESTING (ASNT) ASNT-TC-IA

Recommended Practice

PORTLAND CEMENT ASSOCIATION (PCA) PCA IS 003D

Rectangular Concrete Tanks

PCA IS 072D

ircular Concrete Tanks without Prestressing

NATIONAL CONCRETE MASONRY ASSOCIATION (NCMA) NCMA TEK 59

Reinforced Concrete Masonry Construction.

OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) OSHA - CR29, 1926/1910 AMERICAN ASSOCIATION OF STATE HIGHWAYS AND TRANSPORTATION OFFICIAL (AASHTO) Standard Specifications for Highway Bridges AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) ASTM A6

Specification for General Requirements for Rolled Steel Plates, Shapes, Sheet Piling and Bars for Structural Use

ASTM A36

Specification for Structural Steel

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ASTM A53

Specification for Pipe, Steel, Blank and Hot-Dipped Zinc-Coated Welded and Seamless.

ASTM A123

Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products

ASTM A143

Recommended Practice for Safeguarding Against Embrittlement of Hot-Dip Galvanized Structural Steel Products and Procedures for Detecting Embrittlement

ASTM A185

Specification for Steel Welded Wire Fabric, Plain, for Concrete Reinforcement

ASTM A193

Specification for Alloy-Steel Temperature Service

ASTM A307

Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength

ASTM A325

Specification for High Strength Bolts for Structural Steel Joints, (Including Suitable Nuts and Plain Hardened Washers)

ASTM A490

Specification for High-Strength Steel Bolts, Classes 10.9 and 10.9.3 for Structural Steel Joints (Metric)

ASTM A500

Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes

ASTM A1011

Specification for Steel, Carbon (0.15 Maximum, Percent), HotRolled-Sheet and Strip Commercial Quality

ASTM A786

Rev. B Specification for Rolled Steel Floor Plates

ASTM A830

Specification for Plates, Carbon Steel Structural Quality, Furnished to Chemical Composition Requirements

ASTM C90

Specification for Load-Bearing Concrete Masonry Units

ASTM C270

Specification for Mortar for Unit Masonry

ASTM F436

Specification for Hardened Steel Washers

ASTM F959

Specification for Compressible-Washer-Type Direct Tension Indicator for use with Structural Fasteners

Bolting

Material

for

High

UNIFORM BUILDING CODE (UBC) UBC

Latest Edition

BRITISH STANDARDS (BS) BS 4

Structural Steel Sections Part 1 Specification for Hot Rolled Sections

BS 4190

Black hexagon bolts

BS 7668

Weldable structural steels

BS 4395

High Strength Friction Bolts and Associated Nuts and Washers for Structural Engineering

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BS 4449

Carbon Steel Bars for the Reinforcement of Concrete

BS 4483

Steel Fabric for the Reinforcement of Concrete

BS 4592

Grating

BS 5950

Structural Use of Steelwork in Buildings

BS 7419

Holding Down Bolts

BS 8004

Foundations

BS 8007

Design of Concrete Structures for Retaining Aqueous Liquids

BS 8110

Structural Use of Concrete

BS EN 20898

Mechanical Properties of Fasteners Part 2: Bolts, Screws and Studs

BS EN 10025

Hot rolled products of now-alloy structural steels and their technical delivery conditions

BS EN 10210-2

Hot Finished Structural Hollow Sections of Non alloy and Fine Grain Structural Tolerances, Dimensions and Sectional Properties.

All references within Specification to CODES shall be replaced with corresponding revisede numbers listed above. INTERNATIONAL STANDARDS ORGANISATION (ISO) ISO 9001:2000 Quality Management Systems – Requirements BRITISH PUBLICATIONS ♦ U.K. Concrete Society Technical Report No. 34: Concrete Industrial Ground

Floors. ♦ Cement and Concrete Association Technical Report 550: Design of Floors on

Ground. ♦ British Cement Association Interim Note 11: The Design of Ground Supported

Concrete Industrial Ground Floors. ♦ CIRIA Special Publication 31: The CIRIA Guide to Concrete Construction in the

Gulf Region. ♦ CIRIA Report No. 91 Early Age Thermal Crack Control in Concrete. ♦ CIRIA Technical Note 21 Control of Thermal and Shrinkage Cracking.

3.

REFERENCE DOCUMENTS DESIGN BASIS SPECIFICATIONS DGS 1782 001

Civil Design Basis

DGS 2010 001

Architectural Design Basis

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DESIGN GENERAL SPECIFICATIONS DGS 6531 010

Fireproofing

DGS 1486 002

Excavation and Backfill for Underground Installations

DGS 1883 001

Structural Steel Fabrication

DGS 1884 001

Structural Steel Erection

DGS 1783 001

Concrete Supply

DGS 1783 002

Concrete Construction

DGS 1783 003

On-Site Testing Laboratory

DGS 1783 004

Grouting

DGS 2520 001

Field Erected Storage Tanks - Design Basis

DGS 2520 002

Field Erected Storage Tanks - General

DGS 1900 003

Basic Engineering Design Data

DGS 0000 001

Fire Protection Design Basis

DGS 1783 006

Pipeline anchor blocks

DGS 1674-001

Design General Specification for Design, Installation. Commissioning and Monitoring of Cathodic Protection for Plant Facilities.

STANDARD DRAWINGS Following Standard Drawings: STD 1781 001

Design Standard “Concrete Works”

STD 1781 002

Construction Standard “Concrete Works”

STD 1881 001

Construction Standard “Steel Structures”

STD 1881 002

Construction Standard “Steel Structures Walkways” and all attached standards

STD-1781-002-001

Anchor Bolts – Materials – Fabrication Marking (Sheet 1)

STD-1781-002-001

Anchor Bolts – Materials – Fabrication Marking (Sheet 2)

STD-1781-002-002

Anchor Bolts – Type T

STD-1781-002-003

Anchor Bolts – Type R

STD-1781-002-004

Anchor Bolts – Type S

STD-1781-002-005

Anchor Bolts – Type Z

STD-1781-002-005

Membrane Protection to Concrete Foundation and Pedestal

STD-1881-001-001

Ladders

STD-1881-001-002

Ladder Details

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4.

STD-1881-001-003

Ladder Attachment on Cold Vessels (<-20C)

STD-1881-001-004

Stairways

STD-1881-001-005

Tubular Handrail

STD-1881-001-006

Automatic Barrier

STD-1881-002-001

Brackets for Platforms (L>1300)

STD-1881-002-002

Brackets for Platforms (L<=1300)

STD-1881-002-003

Brackets for Platforms on Cold Vessels (<-20C) in Operation (L>1300)

STD-1881-002-004

Brackets for Platforms on Cold Vessels (<-20C) in Operation (L<=1300)

STD-1881-002-005 CL3

Bracket for Platforms on Cold Vessels

STD-1881-002-006 CL3 Operation

Bracket for Platforms on Cold Vessels (<-20C) in

STD-1881-002-007

Walkway Over Pipeway

STD-1881-003-001

Davit with Tackle (PA) with Pulley

DOCUMENT PRECEDENCE It shall be the CONTRACTOR’S responsibility to be, or to become, knowledgeable of the requirements of any referenced Codes and Standards. The CONTRACTOR shall notify the COMPANY of any apparent conflict between this specification, the related data sheets, the Codes and Standards and any other specifications noted herein. Resolution and/or interpretation precedence shall be obtained from the COMPANY in writing before proceeding with the design/manufacture. In case of conflict, the order of precedence shall be:

5.

♦

Purchase Order or Contract.

♦

Design Drawings.

♦

Design General Specifications and Standards.

♦

Industry Codes and Standards.

SPECIFICATION DEVIATION/CONCESSION CONTROL Any technical deviations to the Purchase Order and its attachments including, but not limited to, the Project Specifications shall be sought by the CONTRACTOR only through CONCESSION REQUEST format. CONCESSION REQUESTS require COMPANY’S review/approval, prior to proposed technical changes being implemented. Technical changes implemented prior to COMPANY approval are subject to rejection.

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6.

QUALITY ASSURANCE/QUALITY CONTROL Quality Management Systems shall comply with the applicable requirements of ISO 9001:2000 “Quality Management Systems- Requirements”. The CONTRACTOR shall ensure that the MANUFACTURER/VENDOR shall have in effect at all times, a QA programme, which clearly establishes the authority and responsibilities of those responsible for the quality system. Persons performing quality functions shall have sufficient and well-defined authority to enforce quality requirements that they initiate or identify and to recommend and provide solutions for quality problems and thereafter verify the effectiveness of the corrective action. Quality System and Quality Control requirements shall be identified and included in the CONTRACTOR’s Purchase documentation. Based on these requirements, the MANUFACTURER/VENDOR will develop a QA/QC program, which shall be submitted to the CONTRACTOR for review and concurrence. The MANUFACTURER/VENDOR’s QA/QC program shall extend to SUBVENDORs. COMPANY/CONTRACTOR reserves the right to inspect materials and workmanship standards at all stages of manufacture and to witness any or all tests. The MANUFACTURER/VENDOR, 30 days after award but prior to the pre-inspection meeting, shall provide the CONTRACTOR with a copy of its Manufacturing and Inspection Plan for review and inclusion of any mandatory COMPANY/CONTRACTOR witness or hold points.

7.

DESIGN REQUIREMENTS

7.1

REFERENCE CODES AND STANDARDS All structural engineering design shall be within the parameters of the documents listed in Sections 2.0 and 3.0 above, and these documents shall be considered as a part of this design basis.

7.2

MEASUREMENT All dimensions, quantities, and units of measurement shown on drawings, or used in specifications and calculations, shall be given in metric units, except pipe size which shall be given in inches.

8.

SITE SURVEY AND SOILS REPORT COMPANY accepts no liability for the information contained in the Site Survey and the Soils Report (if any).

8.1

SITE SURVEY All design shall be in accordance with the horizontal and vertical controls contained in the survey report prepared by the survey consultant.

8.2

SOILS REPORT

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All design shall be in accordance with the recommendations contained in the soils report prepared by the geotechnical consultant. 9.

BASIC DESIGN AND DRAWING CONCEPTS

9.1

DESIGN AND CALCULATIONS

9.1.1

Prior to starting detailed design, a basic design shall be made consisting of:

9.1.1.1

♦

Basic sketch

♦

Loading Derivation

♦

Calculation

♦

Stability check

♦

Main Structural members

Basic Sketch The sketch shall show the proposed structure (in perspective and/or a series of cross sections). Structural members may be shown as single lines. The sketch shall include the foundations, and also which part(s) of the structure will be steel and which part(s) concrete. All applied loads shall be shown on the sketch, excluding the weight of the structure proper.

9.1.1.2

Calculations The calculation shall give the design philosophy and shall follow all loads, including the estimated own weights of t he relevant structural components. The calculation shall state the loads in the main structural members (axial loads, bending moments, shear and possibly torsion), and shall include the loads on the foundation (load per unit of area). The calculation shall take into account the soil investigation report. If any computer programs are to be used for the detailed design, these shall be identified during the basic design stage and all required documentation shall be supplied to demonstrate their accuracy and applicability.

9.1.1.3

Stability Check The stability of the structure shall be checked for both factored and non-factored load combinations.

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9.1.1.4

Main Structural Members In the assessment of the sizes and dimensions of the main structural members the most critical load combination shall be considered. Structural details, such as connections of steel beams and columns or details of reinforcing steel over the full length of a reinforced concrete beam, shall be designed and detailed by the DESIGNER. Standard steel connection details may be designed by the SUPPLIER but shall be checked by the DESIGNER.

9.1.2

Detailed Design The detailed design shall be based on the basic design. The calculation shall clearly indicate: 1.

The table of contents

2.

Design philosophy to include engineering assumptions

3.

Applicable codes, formulas, graphs/tables

4.

References to literature, etc., for subjects not covered by applicable codes

5.

Loading tables with loading location diagrams

6.

If computer programs are used, the f ollowing information shall be supplied: a.

Logic and theory used

b.

Analytical model of the structure used for computer analysis

c.

Users manual

d.

A hand calculation to prove the validity of the computer analysis except if validated by QA/QC system.

e.

Loads and load combinations

9.2

DRAWINGS AND RELATED DOCUMENTS

9.2.1

General Drawings shall be of the standard metric sizes, i.e. A0, A1, A2, A3, A4. The preferred computer aided design system is the software produced by the Intergraph Corporation or other software approved by COMPANY. They shall be suitably prepared to facilitate microfilming and incorporate a numbering and indication of revision system. Dimensions on the drawings shall be in the SI system, unless otherwise specified. Levels shall be indicated in metres, all other dimensions in millimeters.

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Lay-out drawings shall show the highest point of grade as El. 100.00 and the reference of this level to the local datum level for Process Units, in offsites the actual level shall be indicated. All headings and notes shall be in English. Each drawing shall bear the following information, in the title block: ♦

order number of the COMPANY

♦

name of plant

♦

name of unit

♦

name of part of the unit

Example: ♦

order number

♦

catalytic cracking unit

♦

compressor building

♦

portal frames

Only drawings marked "Released for Construction" shall be used at the site. This mark "Released for Construction" can be given only by the DESIGNER responsible for design and engineering. Drawings shall be submitted together with the relevant calculations, including those required for submission to local authorities. Revisions to drawings shall be identified with symbols adjacent to the alterations, a brief description in tabular form of each revision shall be given and, if applicable, the authority and date of the revision shall be listed. The term “Latest Revision” shall not be used. Claim to all drawings prepared by the CONTRACTOR under any order placed by the COMPANY shall be vested in the COMPANY, and the latter shall have the right to use these drawings for any purpose without any obligation to the CONTRACTOR. The CONTRACTOR shall not disclose or issue to third parties without written consent of the COMPANY any documents, drawings, etc., placed at his disposal by the COMPANY or any documents prepared by himself in connection with inquiries and orders for purposes other than the preparation of a quotation or carrying out these orders. 9.2.2

Structural concrete

9.2.2.1

Plan drawing

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On this drawing the general information/data shall be shown as General Notes on the right-hand side of the drawing. The general notes shall state that: a.

Levels are expressed in meters, with reference to the highest point of grade

b.

Dimensions are expressed in millimeters

c.

Bar diameters are expressed in millimeters

Furthermore, the general notes shall list:

9.2.2.2

d.

The quality (or qualities) of concrete*

e.

The quality (or qualities) of steel reinforcing bars*

f.

The quality (or qualities) of cement to be used*

g.

Concrete blinding (location, quality and thickness)

h.

Polyethylene sheeting, if applicable (location and quality)

i.

The concrete cover on bars (type of construction, location and thickness)

j.

The list of reference drawings and related documents stating their title and number

k.

The legend of the CONTRACTOR’S reinforcing bar call out

*

Including an indication for which part(s) each quality is to be used.

Detail drawings On each of the detail drawings, the following information/data shall be listed:

9.2.2.3

a.

For general notes, see Drawing No. ......

b.

This detail drawing refers to Drawing No. ......

c.

For bar bending list(s), see No. ......, sheet 1 to .......

d.

For weight list(s), see No. ........, sheet 1 to ........

e.

Quantity of concrete (for each quality of concrete separately)

Bending and weight lists These lists shall always be made by the DESIGNER, unless explicitly stated otherwise. The lists shall be prepared on the detailed drawings or on separate sheets.

9.2.2.4

Scale of drawings Plan drawings shall be made to a scale of 1:50 and detail drawings to a scale of 1:20.

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9.2.3

Structural steel

9.2.3.1

General Part of the information/data supplied by the COMPANY may be in the form of one or more instruction drawings. If instruction drawings are provided, all the dimensions shown on these drawings shall also appear on the CONTRACTOR’S drawings.

9.2.3.2

General arrangement drawings This drawing shall show the complete structure to be supplied. All main dimensions and the section to be used shall be included. All members to be fireproofed shall be marked with an appropriate symbol or FP designation. A fireproofing legend shall clearly identify the symbols and designations with the work to be performed. For the preparation of the general arrangement drawing, the CONTRACTOR may use a reproducible of the instruction drawing(s). For small and simple structures this drawing may be combined with the baseplate drawing.

9.2.3.3

Baseplate drawing This drawing shall show all dimensions and details of the baseplate including anchor bolts, which shall be taken into account in the design of the (concrete) foundation. When the need for a slight adjustment of the anchor bolts during erection is expected, this shall be indicated on the drawing. The scale for details shall be at least 1:10. For small and simple structures this drawing may be combined with the general arrangement drawing.

9.2.3.4

Construction drawings These drawings shall clearly show all constructional details of the structure to be supplied. The location of the various parts in the structure shall be indicated.

9.2.3.5

Scale of drawings Drawings shall be made to an appropriate scale.

9.2.3.6

Bills of material Bills of material shall show the weights of all large members, in view of transportation and erection at site, and also the total weight of the structure.

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9.3

STEEL STRUCTURES

9.3.1

Structural steel design shall be in accordance with the referenced AISC specifications and codes. The plastic design method in the AISC Manual shall not be used in steel design.

9.3.2

Steel structures shall be designed for the loads and load combinations specified in Sections 10.0 and 11.0 of this specification.

9.3.3

Normally, only pinned column bases shall be used in the design of steel structures. Use of fixed base plates for certain type of pipe racks and buildings may be necessary because of deflection considerations.

9.3.4

Where headroom, access, or equipment arrangement will permit, wind and other lateral loads on a steel structure shall preferably be carried to the foundations through vertical X−bracing or K-bracing placed in the transverse and longitudinal column lines of the structure. As a second choice, wind and other lateral loads on a structure should be transmitted to the foundations through moment resistant frames in one direction and vertical X-braced or K-braced frames in the other direction. Structures that resist lateral load with rigid frame systems in two directions should be avoided. The method of bracing selected for a structure should generally be used throughout the structure.

9.3.5

Compression bracing for steel structures shall normally be designed with wide flange and structural tee shapes. For tension bracing, single angle or structural tees may be used. Double angle bracing, because of maintenance difficulties, is not permitted for either compression or tension bracing. When using structural tees in compression, the design shall include bending induced by eccentrically loaded connections.

9.3.6

Braces for structures subject to vibration from equipment shall be designed as compression braces.

9.3.7

Horizontal bracing shall be provided in the plane of a floor, platform, or walkway, when necessary to resist lateral loads or to increase the lateral stiffness of the floor, platform, or walkway. Floor grating shall not be assumed to resist lateral loads in diaphragm action. Floor plate should be investigated before it is considered to resist loads in diaphragm action.

9.3.8

In a floor system, beam compression flanges should be considered to be fully braced when a concrete slab is cast to match the bottom face of the compression flanges on both sides, or when checkered plate is bolted or welded to the compression flanges, or when grating or metal deck is welded to the compression flanges. Grating shall normally be clipped or bolted and therefore shall not be considered as adequate compression flange bracing. In such cases, additional vertical and/or horizontal bracing in the floor system shall be provided.

9.3.9

Bar joist floor and roof systems are generally considered to be too light for heavy industrial plant work. However, when approved by the DESIGNER, bar joist systems may be used on a project.

9.3.10

Steel Structures shall be designed so that the surfaces of all parts will be readily

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accessible for inspection, cleaning and painting. Pockets for depressions which would hold water shall have drain holes or be otherwise protected. 9.3.11

Connections for steel structures shall conform to the following requirements:

9.3.11.1

Shop connections may be bolted or welded. Field connections shall normally be bolted; however, when approved by the DESIGNER, welded field connections may be used.

9.3.11.2

Bolted connections for primary members shall utilize high-strength bolts conforming to ASTM A325 or A490. A minimum of 2 M20 bolts shall be used for all connections. These connections shall be designed as bearing type connections. Those connections subject to vibration or stress reversal shall be bearing type. Loads for bearing type connections shall be based on threads excluded from shear plane. Turn of the nut method or load-indicator washers shall be used for tightening all connections.

9.3.11.3

Bolted connections for secondary members (e.g. purlins, girts. stair framing. etc.) shall be made with A307 bolts with the appropriate finish.

9.3.11.4

Connections will normally be designed by the SUPPLIER and checked by the DESIGNER in accordance with the project construction specifications and loads shown on the drawings. Moment connections and special connections, however, shall be designed by the DESIGNER and shall be shown on the engineering drawings.

9.3.11.5

Moment connections can be bolted or welded type depending on the type of structure and situation. The DESIGNER will determine the type of connection to be used for each structure. All shear connections shall be designed and detailed by the SUPPLIER and checked by the DESIGNER. Reactions shall be shown on the engineering drawings or as per the calculation note provided by DESIGNER.

9.3.11.6

Plant area shall have the primary structural connections continuously seal welded except high strength bolted field connections. Primary structural connections include horizontal and vertical vessel supports, beams and columns on major pipe racks, inaccessible maintenance areas, etc.

9.3.11.7

The forces in truss members and all main bracing shall be shown on the engineering drawings with plus signs indicating tension and minus signs indicating compression or as per the calculation note provided by DESIGNER.

9.3.11.8

The minimum thickness of any structural steel plate or bar shall be 10 mm. Gusset plates shall not be thinner than the members to be connected, and shall have a thickness of at least 10 mm. CONTRACTOR shall note that the minimum thickness of any plate of a rolled section for use as a structural element should not be less than 6mm”.

9.3.11.9

Welded steel grating for platform covering shall be 30 mm x 6 mm bearing bars at 30 mm on center. Cross bars shall be twisted square 6 mm on each side and spaced not

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over 100 mm center to center and shall be hot-dip galvanized in accordance with ASTM A123 and A143 for a corrosive environment. 9.3.11.10

E70xx welding electrodes shall be specified for all shop and field welding of structural steel. All welds shall be continuous.

9.3.11.11

All bracing shall be arranged to minimize torsion and where practicable, be arranged concentrically about the resultant line of force. The connections wherever possible, shall be arranged so that their centroid lies on the resultant of the forces they are intended to resist. When the condition cannot be achieved, the members and connections shall be designed to resist any local bending due to the eccentricity of the force.

9.3.11.12

In practice it is noticed that corroded steel plates and bolts limit the expected movement which may result in additional stresses. The DESIGNER should consider this potential for additional stresses in their design consideration.

9.3.12

Steel structures supporting equipment shall be fireproofed where required by safety analysis. For F.P. criteria, see Section 9.8.

9.4

REINFORCED CONCRETE STRUCTURES AND FOUNDATIONS

9.4.1

Cast-in-place concrete structures shall be designed in accordance with ACI 318 except as specified otherwise in this specification.

9.4.2

Cast-in-place concrete structures shall be designed for the loads and load combinations specified in Sections 10.0 and 11.0 of this specification.

9.4.3

The strength design method shall be used for the structural design of concrete members unless otherwise indicated. Load combinations and load factors for all concrete design shall be in accordance with ACI 318.

9.4.4

The design and details of cast-in-place concrete structures shall consider the monolithic nature of concrete construction.

9.4.5

Construction joints in a concrete structure shall be located so as to least impair the integrity and strength of the structure. Construction joints in beams at column or pedestal faces should be avoided. The DESIGNER/CONTRACTOR Site Management shall approve the location of all construction joints.

9.4.6

Moving concentrated loads on elevated concrete beams and slabs shall be treated in accordance with applicable recommendations of the referenced AASHTO specifications.

9.4.7

Slabs at grade for buildings and process areas shall be designed in accordance with the publications as per Section 9.5.11.

9.4.8

Concrete pavements for heavy storage areas shall be designed in accordance with the publications as per Section 9.5.11.

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9.4.9

Underground structures such as basements, rectangular tanks, sumps, and pits shall be designed in accordance with the latest referenced PCA bulletins and/or BS8007. The design of such structures shall include the effects of ground water pressures and buoyancy. A minimum factor of safety of 1.1 for buoyancy shall be used, ignoring soil cohesion. Concrete process treatment structures shall be designed in accordance with ACI 350 R. For all liquid retaining structures, special precautions should be taken for water tightness. All joints shall be fully detailed by DESIGNER.

9.4.10

A corrosion allowance of 3 mm shall be required for all anchor bolts. Bolts shall be hotdip galvanized in accordance with ASTM A123 and A143.

9.4.11

Foundation design, in addition to the above applicable criteria, shall include the following requirements:

9.4.11.1

Foundations shall be designed in accordance with the project geotechnical (soils) report.

9.4.11.2

Foundations for structures shall be sized and stability determinations shall be made using service loads only. Load factors shall not be included in these design operations.

9.4.11.3

Unless there is a conflict with the project soils report, individual foundations are normally used for major equipment. If combined foundations are appropriate, the centroid of the bearing area should coincide with the resultant of the applied operating load (excluding live load).

9.4.11.4

All foundations shall be placed on seal (blinding) slabs. The seal slabs shall be placed on firm, undisturbed soil. Some seal slabs, however, may be placed on wellcompacted earth fill, if approved by the DESIGNER. In such cases, the engineering drawings shall specify the kind of fill material and the degree of compaction required for the fill material.

9.4.11.5

Spread footings, combined footings, and mats should be designed assuming linear soil pressure distribution. Where the rigidity of the foundation is questionable, however, an analysis considering the interaction between flexibility of the foundation and the subgrade soil reaction should be considered. For mats especially, this method of analysis may be in order. ACI 336.2 R contains suggested design procedures.

9.4.11.6

Foundations shall be proportioned so as to minimize general and differential settlements.

9.4.11.7

In order to reduce the overturning moment on individual footings of buildings and process structures, the transfer of column base shears into the concrete grade slab should be considered. The frictional resistance provided by the grade slab shall equal at least 1.15 times the applied column base shears. For design purposes, a coefficient of friction of 0.2 may be assumed between the concrete slab and the membrane. If this design approach is used, the grade slab thickness and joint details shall be properly designed.

9.4.11.8

Where seasonal changes in soil moisture content are extreme at a site, special details

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may be required to minimize foundation movements. Control of foundation movements is especially critical for masonry structures. The DESIGNER shall determine design parameters to control movement. 9.4.11.9

The stability ratio (SR), based on service loads, for isolated spread footings shall not be less than 1.5 when determined as follows: SR =

D(P) / 2M = D / 2e

Where: D=

Diameter or width of footing

P=

Minimum gravity load at bottom of footing (exclude product and live loads, include buoyancy)

M=

Maximum overturning moment at bottom of footing

e=

Eccentricity = M / P

The uplift factor of safety, based on service loads, shall not be less than 1.25. This factor of safety must be maintained when 70 percent of dead load is combined with no reduction of wind load for uplift. 9.4.11.10

The stability ratio (SR), based on service loads, for buildings, process structures, and other framed structures shall not be less than 1.5 when determined as follows. SR = Resisting Moment / Overturning Moment Where Resisting Moment = Moment due to dead load of foundation and structure (include buoyancy). Overturning Moment = Moment due to lateral loads The overturning and resisting moments shall be computed about the most critical axis of rotation of the foundation block at the soil-concrete interface. There may be more than one axis of rotation.

9.4.11.11

The stability ratio (SR) of retaining walls based on service loads shall not be less than the following: a. For sustained loading: SR

= Resisting Moment / Overturning Moment = 3.5 for cohesive soils = 2.0 for cohesionless material

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SR

= Resisting Moment / Overturning Moment = 2.0 for cohesive soils = 1.5 for cohesionless material

Where: Resisting Moment = Moment due to dead load of wall and soil overburden (include buoyancy) Overturning Moment= Moment due to lateral loads Resisting moment and overturning moment shall be taken about the toe of the retaining wall and bottom of footing. 9.4.11.12

For all service load conditions, the sliding resistance of foundations and retaining walls developed by friction between the footing and membrane shall at least be equal to 1.5 times the applied lateral loads. Stability calculations shall include the weight of the concrete and the soil immediately above the footing. The effects of buoyancy on the concrete and soil weights shall be considered. A) Foundations The sliding resistance of foundations shall be developed by either friction between the footing and membrane or by a combination of friction and passive resistance on foundations. In cases where sliding resistance is developed by a combination of friction and passive resistance then a minimum factor of safety of 2.0 shall be provided. B)

Retaining Walls The sliding resistance of Retaining Walls shall be developed by either friction between the footing and membrane or by a combination of friction between the footing and membrane and passive resistance on keys extending below the bottom of the footing of walls. In cases where sliding resistance is developed by a combination of friction and passive resistance then a minimum factor of safety of 2.0 shall be provided.

9.4.11.13

Foundation bottom level shall be defined taking into consideration geotechnical (soil) report and other factors and shall be clearly identified on the drawings. Keep standard bottom of footing elevations where possible. Consideration shall be given to interferences with underground systems.

9.4.11.14

For additional tank foundation requirements, see Design General Specifications DGS 2520 001and DGS 2520 002.

9.5

PROJECT CONSIDERATIONS FOR REINFORCED CONCRETE

9.5.1

General

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9.5.1.1

The Region has been defined as being in an Ultra Hot Climate, this climate together with the extremely heavy concentration of chlorides in both the ground and atmosphere together with high humidities, have resulted in the rapid degradation of Reinforced Concrete. (R.C.).

9.5.1.2

The degradation of the concrete is principally caused by reinforcement corrosion due to the ingress of chlorides and other aggressive salts, the consequential increased volume of rust product commonly breaks off the cover to the reinforcement. Failure of the R.C. member then becomes imminent. The degradation of concrete arises also from the use of salt contaminated materials.

9.5.1.3

The durability and quality of the concrete itself is of paramount importance. Factors to increase durability shall be incorporated in concrete such as thermal insulation coating measures as recommended in the “CIRIA Guide to Concrete in The Gulf Region”.

9.5.1.3.1

Quality of concrete is achieved by good engineering and detailing, proper materials and proportioning, good construction techniques and concrete curing.

9.5.1.3.2

One of the main characteristics influencing the durability of concrete is its permeability to the ingress of chlorides, water, oxygen, carbon dioxide, wind blown chloride contaminated dust and other deleterious substances.

9.5.1.4

Coatings shall be applied to all buried and exposed concrete surfaces as an added protection against attack from chlorides and other harmful elements and to assist the concrete to develop a refined pore structure and enhanced impermeability. Coatings shall have crack bridging properties on flexural members.

9.5.1.5

Steel plates shall not be embedded in concrete. The CONTRACTOR shall develop a detail that allows attachment of the plates to inserts embedded in the concrete. A detail shall also be developed to ensure an effective seal from exterior moisture is achieved around the perimeter of the plates, at the point of intersection between concrete and plate.

9.5.2

Crack prevention

9.5.2.1

Crack widths shall be controlled by the expeditious use of combinations of reinforcement sizes, reinforcement spacing and cover.

9.5.2.2

Crack widths shall be calculated using the applicable formula in BS 8007.

9.5.2.2.1

The calculation shall be based on the long term, steady state loading. For durability it is not necessary to consider peak loadings, although this may affect coating selection because of the requirement for crack bridging and flexural performance.

9.5.2.2.2

Crack widths apply at the surface of the concrete i.e. the full depth of cover shall be utilized in the calculation.

9.5.2.2.3

Calculation of crack widths shall consider both load (flexural) and restraint (due to thermal and shrinkage effects) induced cracking.

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9.5.2.2.4

In order to reduce flexural cracking to COMPANY acceptance limits, it will be necessary to use reduced allowable stresses in the reinforcement.

9.5.2.2.5

Calculation of crack widths shall not use ‘deemed to satisfy’ options of BS 8007, i.e. do not calculate crack widths on Pcrit and minimum reinforcement ratios.

9.5.2.2.6

The minimum external restraint factor (R) shall be 0.5.

9.5.2.2.7

Methods of calculating crack widths in relation to temperature and moisture effects are given in Appendix A - BS 8007.

9.5.2.2.8

The minimum fall in temperature between hydration peak and ambient (T1) shall not be less than 31° C for walls and 21° C for ground slabs.

9.5.2.2.9

Seasonal temperature fall (T2) shall be considered where continuous construction is used - BS 8007 - Table 5.1 - Option 1. This shall be not less than 30° C.

9.5.2.3

Crack widths shall be limited as follows.

9.5.2.3.1

Crack width shall be ≤ 0.15 mm for all buried, submerged and exposed concrete.

9.5.2.3.2

Crack width shall be ≤ 0.30 mm for all concrete located in an air conditioned and sealed environment.

9.5.2.3.3

Crack widths shall be ≤ 0.10 for all liquid retaining structures.

9.5.3

Reinforcement

9.5.3.1

Use smaller diameter re-bar at closer centers.

9.5.3.2

For sections ≤ 500 mm thick and for the outside 300 mm of large sections reinforcement shall not be less than 0.35% of the applicable gross cross-sectional area of the concrete section.

9.5.3.3

Maximum spacing of reinforcement shall be 150 mm in any direction.

9.5.3.4

Use fabric reinforcement where possible (‘nested’ where necessary) as this gives better crack control.

9.5.3.5

Do not bunch reinforcement or use in vertical or horizontal pairs.

9.5.3.6

Reinforcement shall be adequately detailed to eliminate congested areas, i.e. laps to be staggered.

9.5.3.7

Place reinforcement nearest to the surface where it is the greatest restrained length i.e. this means that horizontal wall reinforcement will be on the outside of the vertical reinforcement.

9.5.3.8

Ensure additional diagonal reinforcement is placed at each re-entrant opening to prevent cracks emanating from corners.

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9.5.3.9

All reinforcement shall be fully detailed including bar bending schedules for fabrication by the DESIGNER.

9.5.3.10

All concrete sections with a thickness of 250 mm or more, reinforcing bars shall be placed on both faces, over the full section. In addition, minimum reinforcement shall be placed in the other two faces.

9.5.4

Concrete Cover.

9.5.4.1

Adequate cover in essential for resistance to corrosion.

9.5.4.2

Cover is to the outside of all reinforcement

APPLICATION Concrete cast against or permanently exposed to earth (all below grade structures) and all marine facilities over or in contact with water Concrete exposed to weather (all above grade structures not enclosed by a temperature and humidity controlled building) Concrete not exposed to weather and located within a temperature and humidity controlled building

MINIMUM CONCRETE COVER (mm) 75

60

50

Where any individual structural element falls within two or more categories then the most stringent criteria shall apply for the entire element. 9.5.4.3

Horizontal re-bar in walls and faces of large elements shall be on the outside of the vertical reinforcement for more effective crack control.

9.5.4.4

All concrete cover shall conform strictly with values given above.

9.5.4.5

Required covers shall not be reduced by provision of protective coatings, membranes or by membrane protective screed.

9.5.4.6

If fire resistance of more than 2 hours is required, then cover shall be as determined in Table 3.5 in BS 8110 Part 1 for the particular element under consideration.

9.5.5

Concrete Grades.

9.5.5.1

Concrete shall have a minimum compressive strength as specified in Specification for Concrete Supply DGS 1783 001.

9.5.6

Externals Features.

9.5.6.1

Features which collect sand and dust which form with rain or dew into a corrosive poultice shall be avoided i.e. decorative patterns with holes and pockets, gutters, ledges and exposed aggregate finishes. Top surfaces shall be designed with falls to

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encourage run-off. 9.5.6.2

Tops of all pedestal heads shall be sloped 1:20 away from the baseplate grout.

9.5.6.3

Top of pedestal shall project a minimum of 100 mm from the edge of the column baseplate grout. Dimensions of the concrete columns or foundations are designed taking into account loads applied to, not by reference to geometric dimensions of base plate.

9.5.6.4

Minimum pedestal heights excluding grout above top of adjacent paving shall be as follows: Structural Steel columns: 150 mm to 200 mm Equipment (general):

100 mm to 300 mm

Equipment (pumps):

100 mm to 300 mm

9.5.6.5

Grout is to be sloped 1:1 away from the bottom outside corner of the column baseplate grout.

9.5.6.6

Shear keys shall not be used on pedestals/plinths.

9.5.7

Stress Raisers.

9.5.7.1

Complicated plan shapes which cause stress raisers shall be avoided.

9.5.7.2

Large and sudden changes of cross-section i.e. wall junctions and counterforts in the middle of bay lengths shall be avoided. Position joints near to these stress raisers or cast in two separate sections.

9.5.7.3

Provide appropriate extra reinforcement where stress raisers are unavoidable.

9.5.7.4

Casting-in pipes, box-outs, notches in the middle of bay lengths shall be avoided, position joints as near to these stress raisers as possible.

9.5.8

Anchor Bolts.

9.5.8.1

For small diameters, Chemical type anchors or cast-in anchors are prefered. Where chemical anchors are used the hole must be properly cleaned according to MANUFACTURER’S instructions.

9.5.8.2

Anchor bolts shall be designed for combined tension and shear as per BS5950.

9.5.8.3

Minimum edge distance, measured to outside of tube shall be 100 mm or 4 times the bolt diameter whichever is greater.

9.5.9

Shear Keys.

9.5.9.1

For standard conventional structures, shear keys shall not be used.

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9.5.9.2

For situations where shear keys are required, back up design calculations and justification shall be provided to the COMPANY for approval.

9.5.10

Pits and Tanks.

9.5.10.1

As a minimum requirement, the recommendations of BS 8007 - Section 5 ‘Design, Detailing and Workmanship of Joints’ shall be adhered to, regardless of whether the structure is liquid retaining or not.

9.5.10.2

All construction joints are to be designed, detailed and shown on the drawings by the DESIGNER or SUBCONTRACTOR for CONSTRUCTION with approval of CONTRACTOR.

9.5.10.3

Where continuous construction is necessary, the method of ‘Temporary Open Sections’ as specified in BS 8007 C1.5.5 shall be used. Such open sections shall not be more than 1.0 m and shall contain the “Lapped’ section of reinforcement.

9.5.10.4

The use of sequential bay wall construction shall not be permitted.

9.5.10.5

Unless roofs are insulated, these sections are subject to extremely high daytime temperatures and lower night temperatures. Consideration shall be given to the use of insulation or reflective coatings (e.g. aluminum).

9.5.10.6

All such structures (other than blast resistant structures) are to have an isolated roof slab on a sliding beating (slip strip or equal approved). Monolithic construction with the supporting wall shall not be considered in the design.

9.5.11

Paving.

9.5.11.1

For ground slab paving construction, the method used for design and construction shall be by the alternate ‘long strip method’ using a combination of transverse contraction joints (induced or formed). Adjacent longitudinal strips shall be cast with longitudinal tied joints between each strip.

9.5.11.2

The recommendations for slab design and construction shall be provided in the following publications:-

9.5.11.2.1

Design of Floors on Ground by Cement and Concrete Assoc. Tech. Report 550.

9.5.11.2.2

Concrete Industrial Ground Floors by U.K. Concrete Society Technical Report #34.

9.5.11.2.3

The Design of Ground Supported Concrete Industrial Ground Floors by British Cement Assoc. Interim Note 11.

9.5.11.2.4

Guide for Concrete Floor and Slab Construction by ACI 302.1R.

9.5.11.3

The location of all joints shall be shown on the drawings with accompanying details of each joint type.

9.5.11.4

Isolation joints are to be provided around all equipment foundations and pedestals.

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9.6

CONCRETE MASONRY STRUCTURES The design of concrete masonry structures shall conform to ACI 530 and the UBC. Concrete masonry structures shall be designed for the loads and load combinations specified in Sections 10.0 and 11.0 of this specification.

9.7

GROUTING All grout materials and application procedures shall be approved by the DESIGNER and the MANUFACTURER. Sand-cement grout shall not be used for this project. All grouting shall be in accordance with Spec.DGS 1783 004.

9.7.1

Epoxy-based non-shrink grout shall be evaluated by CONTRACTOR and the MANUFACTURER for each application for temperature creep and strength and be used in accordance with MANUFACTURER'S specification.

9.7.2

Grout material used below base plates for machinery, pipe racks, pumps, pipe supports, etc. shall not be placed higher than the bottom of plate level and shall be sloped outward at a 1:1 slope away from the bottom of the base plate to prevent water accumulation near the base plate and also to prevent cracking of the grout as a result of corrosion around base plate edge. CONTRACTOR shall develop a detail to ensure an effective seal from exterior moisture is achieved around the perimeter of the baseplates at the point of intersection between grout and baseplates.

9.8

FIREPROOFING See Fire Protection Design Basis Specification DGS 1900 003.

9.8.1

Fireproofing zones.

9.8.1.1

Only specific structures and equipment located within a Fire Proofing Zone (FPZ) shall be fireproofed as described in Specification for Fireproofing DGS 6531 010.

10.

LOADS.

10.1

Buildings, Process Structures, Pipe Racks, Miscellaneous Plant Structures, Vessels, Exchangers and Tanks.

10.1.1

The following loads shall be considered:

10.1.1.1

Dead Load

a.

Soil Load (Include as part of Dead Load)

10.1.1.2

Operating (Product) Load

10.1.1.3

Test Load

10.1.1.4

Live Load

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a.

Sand Load (Include as part of Live Load)

b.

Surge Load (Include as part of Live Load)

10.1.1.5

Truck Load

10.1.1.6

Wind Load

10.1.1.7

Earthquake Load

10.1.1.8

Crane/Impact Load

10.1.1.9

Dynamic Load

10.1.1.10

Thermal Load

10.1.1.11

Erection Dead Load

10.1.1.12

Maintenance Load

10.1.1.13

Miscellaneous/Differential Settlement Load

10.1.1.14

Earth/Hydrostatic Load and Buoyancy

10.1.1.15

Blast Load

10.1.1.16

Future Load

10.1.2

The above loads are defined as follows.

10.1.2.1

Dead Load Dead load is defined as the weight of all permanent construction including walls, foundations, floors, roofs, ceilings, partitions, stairways, and fixed service equipment. For heavy industrial work, this would include equipment, vessels including internals, pipes, valves, and accessories; electrical and lighting conduits, switchgear; instrumentation, fireproofing; insulation; ladders; platforms; and other similar items. Weight of equipment shall be derived from the MANUFACTURER’S data sheets and shall include auxiliary machinery and piping. Equipment and piping should be considered empty of product load when calculating dead load. The gravity weight of soil overburden shall be considered as dead load. a.

Soil Load (Dead Load)

Soil loads shall consist of lateral earth pressures. Active and passive coefficients for lateral pressures shall be obtained from the project soils report. 10.1.2.2

Operating (Product) Load (Live Load) The load shall be defined as the gravity load imposed by liquid, solid, or viscous

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materials in vessels, tanks, equipment, or piping during operation. Unusual loading that occurs during regeneration or upset conditions shall also be considered. 10.1.2.3

Test Load (Live Load) The test load shall be defined as the gravity load imposed by any method necessary to test vessels, tanks, equipment, or piping. When more than one vessel, etc., is supported by one structure, the structure need only be designed on the basis that one vessel will be tested at any one time, and that the others will either be empty or still in operation.

10.1.2.4

Live Load Live load is defined as the weight superimposed by the use and occupancy of the building or other structure, but not permanently attached to it. For industrial design, live load can be defined as the load produced by personnel, moveable equipment, tools, and other items placed on the structure, but not permanently attached to it. Unless specified otherwise, use the minimum live load values given in the table below. Uniform loads and concentrated loads do not occur simultaneously. Types of Structures Walkways (not used as operating)

2.0 (or 3.0 kN point load)

Operating platforms (other than compressor and generator platforms


Trench covers (nonvehicular)

5.0

Roof (min)


Sand on roof (min.)

0.75

Light Storage

6.25

Heavy Storage

12.5

Compressor and generator platforms; Floor framing (Determine from use but never less than) Floor Grating and Slabs *

DGS-1882-001/FH

5.0 10.0*

For floor grating and slabs being subjected to a concentrated load from either the installation or removal of equipment

Office first aid buildings, guards houses, control room, computer room, electrical equipment room, laboratory room locker room

3.0

Canteens, Lunchrooms, Stairs, Halls

4.0

Library

5.0

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Battery rooms Mechanical, electrical, workshop building

10.0 instrument

20.0

Bulk storage

40.0

Stairs and Ramps


Handrailing

**

**

a.

0.75 kN per linear meter applied horizontally at the top of railing, or a horizontal force of 0.9 kN at any one point. Sand Load (Live Load)

Sand load shall be additive to live loads only when the area under consideration is 2 used as a work area. A 0.75 kN/m load shall be used in the design of flat roofs. The effect of sand accumulating behind walls and upstands shall be considered in the design of the walls and roof (treat as similar to snow loading). b.

Surge Load (Live Load)

Surge loads may occur in some vessels or equipment such as fluid cokers, hydroformers, crackers, etc. In such cases, the magnitude and direction of the load will be given in the equipment specification. The project process engineer shall furnish a list of equipment having surge loads and the designer shall make allowance for such loadings in relevant calculations. 10.1.2.5

Truck Load (Live Load) Structures accessible to trucks shall be designed to withstand the gravity, lateral and impact effects of truck loading. Truck loading shall be HS20 or HS20-44 wheel loading as defined by the AASHTO specifications. It shall be checked where applicable, whether maintenance and/or construction equipment loads are governing over HS20 wheel loading. At least one road leading to the main process area(s) shall be designated as a heavy equipment route. Bridges, culverts and other underground facilities shall be designed for the maximum expected loading condition caused by transportation of heavy equipment.

10.1.2.6

Wind Load (Live Load) The design wind loads shall be calculated based on a basic wind speed at a height of 10 m above the ground, for terrain exposure C, and a mean recurrence interval of 50 year. For this exposure and recurrence, the value of the importance factor of (I) =1.1. The DESIGNER shall develop specific wind load, calculation criteria and procedures using ASCE 7 for various types of structures and equipment for the project. For overhead pipe tracks of 4m wide or less, the wind load on the three largest pipes shall be taken into account. For overhead pipe tracks of over 4m wide, the wind load on the four largest pipes shall be taken into account.

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The following tabulated velocity pressures shall be used for calculating design wind forces for the design of all structures, buildings and equipment and their parts, portions and appurtenances for the project. Pressure coefficient, C f = 0.8: Pipe racks 4 m wide or less: W p = 0.8 qh (D1+D2+D3) or pipe racks wider than 4 m: W p = 0.8 qh (D1+D2+D3+D4) Where W p = Unit design wind load on piping qh = Velocity pressure determined at piping elevation, h Dn = Diameter of pipe

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Use the Basic Wind Speeds Specified below to calculate the Design Wind Loads for ABU DHABI GAS INDUSTRIES LTD. (GASCO) Ruwais Basic wind Speed 3-second gust for structural design is 175 km/hour and all other plants e.g. Habshan/Bab, Buhasa& Asab use ASCE 7-98 Height Zone Above Grade (m) Z

Velocity Pressure in Kg/m2 qz

Gust Response Factors Gh and Gz

0-6

107

1.29

6-9

114

1.26

9-12

125

1.25

12-15

134

1.22

15-18

142

1.21

18-24

151

1.18

24-30

164

1.17

30-36

173

1.15

36-45

183

1.14

45-60

198

1.12

60-90

219

1.10

90-120

241

1.08

TABLE for Shape Increase Factors Vessel Diameter (m)

Increase Factor

0.5 – 1.0

1.60

1.0 – 1.5

1.37

1.5 - 2.0

1.28

2.0 - 2.5

1.20

2.5 and up

1.18

Spherical

1.10

(any diam) Increase factors may be used to modify the projected areas of vertical and horizontal vessels (including insulation, if any) to allow for attachments such as manholes, nozzles, piping: ladders and platforms. The following shape increase factors may be used to modify the projected areas of DGS-1882-001/FH

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vertical and horizontal vessels (including insulation, if any) to allow for attachments such as manholes, nozzles, piping, ladders, and platforms. Use Cf = 0.8. Wind loads shall be separately computed for all supported equipment, ladders, and stairs except for vessels where projected area increase factors have already accounted for these items. Gust response factors, G, for main wind resisting systems of flexible buildings, structures, and vertical vessels having a height exceeding five times the least horizontal dimension or a fundamental natural frequency less than 1.0 hertz shall be calculated. Calculations shall be based on a rational analysis that incorporates the dynamic properties of the main wind force resisting system. One such procedure for determining gust response factor is described in ASCE 7-93, Commentary. No reduction shall be made for the shielding effect of vessels or structures adjacent to the structure being designed. NOTES: For main wind-force resisting systems and walls, use Gh evaluated at the height h (top) of the structure. An exception is in the various structural specifications for equipment, the variable gust response factor Gz is used. For components and cladding, use Gz evaluated at centroid height z above ground. 10.1.2.7

Earthquake Load (Live Load) Earthquake load shall be calculated and applied in accordance with Uniform Building Code (UBC-1997) using Zone as specified and an importance factor of 1.0.

10.1.2.8

Crane/Impact Load (Live Load) For structures carrying live loads which induce impact, the live load shall be increased sufficiently. If not otherwise specified, the live load increase shall be following: Category For supports of elevators (dead and live load) Cab operated travelling crane support 3 girders and their connections Pendant operated travelling crane 3 support girders and their connections Monorails, trolley beams, davits Light machinery, shaft or motor driven Reciprocating machinery or power driven units Hangers supporting floors and balconies 1.

DGS-1882-001/FH

Vertical Load 100%

Horizontal Load

25%

20% 2 10%

1

10% 50% 20% 50% 33%

Increase the sum of the weights of the rated capacity of hoist, crane trolley, cab

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and hooks. Apply one-half of the load at the top of each rail, acting in either direction, normal to the runway rails.

10.1.2.9

2.

The longitudinal force shall, if not otherwise specified, be taken as 10% of the maximum wheel loads of the crane applied at the top of the rail.

3.

Live load on crane support girders shall be taken as the maximum wheel loads.

Dynamic Loads (Live Load) Each structure shall be designed to withstand the effects of vibration and impact to which it may be subjected. Each structure and foundation supporting a compressor, turbine, pump or other machinery having significant dynamic unbalance shall be designed to resist the peak loads specified by the manufacturer. Vibration amplitudes of the supporting structure or foundation shall be kept within acceptable limits for dynamic forces that occur during normal machine operation. In the case of a tall and slender structure, there may be a need to investigate the dynamic effects of wind gusts. Centrifugal pump foundations for pumps less than 750 kW do not require a dynamic analysis. However, the foundation to pump assembly weight ratio shall not be less than 3 to 1. Foundations for reciprocating machinery, centrifugal machinery, and centrif ugal pumps over 750 kW require a three dimensional dynamic analysis.

10.1.2.10

Thermal Load (Live Load) ASCE 7 mentions thermal loads; however, the ASCE thermal comments are not geared to heavy industrial work. Thermal loads shall be defined as forces caused by changes in temperature. The primary source of thermal loads in an industrial plant is the expansion or contraction of vessels and piping. Another source of thermal loads in a redundant structure is the expansion or contraction of the entire structure or individual structural components. Provisions shall be made for thermal forces arising from assumed differential settlements of foundations and from restrained dimensional changes due to temperature changes. Thermal loads and displacements caused by operating conditions shall be based on the design temperature of the item of equipment rather than the operating temperature. o

Design atmospheric temperature ranges from a minimum of 5 C to a maximum of o 58 C. Low friction slide plates (Fluorogold, Teflon or an approved equal) shall be used if the vessel operating condition weight is greater than 45 kN at the sliding end. For o preliminary design, the temperature drop of 1.9 C/mm from the bottom of shell to bottom of saddle may be assumed. The following friction coefficients shall be used for calculating frictional restraint due to temperature change or lateral loading on sliding surfaces: DGS-1882-001/FH

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Surface Steel-to-steel (corroded) Steel-to-concrete Teflon-to-teflon

Friction Coefficient 0.35 0.50 0.17 to 0.08

A straight line variation of 0.17 to 0.08 for bearing 2 Stresses from 0.0 N/mm to 0.7 2 N/mm , respectively Bearing stress greater than 0.7 N/mm Graphite-to-graphite

0.08

2

0.15

For computing friction loads due to the effects of pipe expansion in pipe racks, use the following friction coefficients: Number of Lines on Support

Friction Coefficient

1-3

0.3

4-6

0.2

7 or more

0.1

For a given support, if considering only larger lines and ignoring smaller lines results in greater loads, these forces and associated friction coefficients shall be used instead of considering all the lines. A concrete pipe rack beam shall be designed for an arbitrary horizontal pipe anchor force of 15 kN acting at midspan unless design calculations dictate a higher force and more locations. The pipe anchor force shall not be distributed to the foundations. For pipe anchor forces transferred by longitudinal girders to structural anchors (bracing) an arbitrary force of 5% of the total pipe load per layer shall be taken into account, unless design calculations dictate a higher force. These forces shall be distributed to the foundations. Foundations and structures which are subject to temperature effects shall be designed for the various loading conditions and also for any temperature difference which may occur in parts of structural members.

10.1.2.11

a.

Anchor and guide forces shall be obtained from the DESIGNERS Piping Engineering Department.

b.

Structural Steel Pipe Supports shall be designed in accordance with Industry Standard Structural Design Methods.

Erection Dead Load The erection dead load is the weight of the equipment at time of erection plus the weight of the foundation. The foundation weight is the combined weight of the footing,

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pedestal, and overburden soil. All possible loading conditions during erection shall be considered and, for any member of a structure, the most unfavorable shall be taken into account. Heavy equipment lowered onto a supporting structure can introduce extreme point loads on structural members, exceeding any operating or test load. After placing of equipment, the exact positioning (lining out and leveling) can also introduce extreme point loads. The above should be interpreted on the basis of contractor’s practical experience and manufacturer’s information and allowed for in the design calculations. Beams and floor slabs in multistory structures, e.g. fire decks, shall be designed to carry the full construction loads imposed by the props supporting the structure immediately above. A note shall be added on the relevant construction drawings to inform the field engineer of the adopted design philosophy. 10.1.2.12

Maintenance Loads (Live Load) Maintenance loads are temporary forces caused by the dismantling, repair or painting of equipment. The force required to remove the tube bundle from a shell and tube heat exchanger shall be assumed to act along the horizontal centerline of the exchanger and shall have a value of 2 times the weight of the bundle, but not less than 10 kN.

10.1.2.13

Miscellaneous Loads (Live Load) Miscellaneous loads shall be defined as loads that do not fit into the categories listed in this section.

10.1.2.14

Earth/Hydrostatic Load and Buoyancy (Live Load) Earth and hydrostatic water pressures on retaining walls and underground structures shall be determined. Outward pressures on liquid-retaining structures shall also be considered. The buoyancy load is equal to the weight of the volume of displaced water.

10.1.2.15

Blast Load (Live Load) Where applicable earthquake loads shall be taken into account.

10.1.2.15.1

Negligible Blast Buildings located more than 610 m away from the potential explosive sources do not require special provisions with regard to explosion resistance.

10.1.2.15.2

Blast Resilient Buildings within the 200 m to 610 m distance from potential explosive sources shall be designed to the same loading conditions as specified for buildings beyond the 610 m zone and in accordance with the f ollowing design concepts:

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♦

The building structural frame, roof, walls, bracing, and connections, shall be designed in such a manner that large plastic deformations of the major frame members and external wall panels will be allowed to take place, without causing partial or total building collapse.

♦

Blast resilient building shall be designed and detailed in accordance with either ACI 318 M, Chapter 21,” Special Provision for Seismic Design.

OR Design of Blast Resistant Building in Petrochemical Facilities By ASCE Task Committee on Blast Resistant Design Sponsored by American Society of Civil Engineers.

10.1.2.15.3

♦

The building frame shall be reinforced concrete or structural steel.

♦

The building walls shall be constructed as reinforced concrete, reinforced masonry with concrete filled cells or properly designed carbon steel cladding system. Walls for these buildings shall not be used as main frame members or to provide structural stability and/or structural strength.

♦

The building roofs shall be constructed of monolithic reinforced concrete or a properly designed carbon steel roofing system. Loose light-weight concrete roof slabs or asbestos cement sheeting shall not be used. Gravel as a protection of roof finish, or loose tiles for walkways on top of the roof finish, shall not be used.

♦

For steel structures, structural steel bracing in roof and walls shall be provided.

♦

Materials with a brittle behavior, such as masonry, shall not be used in such a way that they have a strength function.

♦

For additional architectural construction requirements, refer to Specification for Architectural Design Basis No. DGS 2010 001.

Blast Resistant Buildings within 200 m distance from the potential explosive sources may be designed to withstand the anticipated blast effect. The blast loads or pressures to be used for the design of various structural elements shall be calculated in accordance with an acceptable method which takes into account the dynamic response. The calculated blast loads shall not be less than the following equivalent static loads acting inward or outward perpendicular to the surface: 2

•

External Walls 100 kN/m , except loads on doors and windows which may be 2 assumed to be 30 kN/m .

•

Blast loads on the roof slab is dependent on the span between supports 2

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ABU DHABI GAS INDUSTRIES LTD. (GASCO) STRUCTURAL DESIGN BASIS 2

45 kN/m for span of 4m 2 40 N/m for span of 5m 2 35 kN/m for span of 6m 2 30 kN/m for span of 7m 2 25 kN/m for span of 8m and over It is to be assumed that the blast loads will act simultaneously on and over one wall and the roof. These loads act with applicable dead loads: ♦

Suction on walls and roof shall be 50% of the above-mentioned static loads, and it is to be assumed that these loads will act simultaneously on one wall and the roof and not in combination with above-mentioned loads.

♦

Structures shall be detailed in accordance to ACI 318, Chapter 21, “Special Provisions for Seismic Design”. Pre-stressed concrete shall not be used. In general, special attention shall be paid to ensure continuity and a minimum of local stress concentration. Adequate lapping of reinforcement is required. The following provisions shall supersede ACI 318, Chapter 21, for Blast Resistant structures:

♦

The concrete walls and slabs shall be reinforced each side in the main direction with a minimum of 0.6% in the case of steel bars with a yield strength of 410 2 N/mm and a minimum elongation of 14%. In the other direction on both sides, a distribution reinforcement of at least 20% of that in the main direction shall be applied. Maximum spacing of bars shall be 150 mm center to center. It is preferable for the wall and roof thicknesses to be between the limits of 250 and 400 mm in order to facilitate the placing of the required reinforcing bars.

Shear reinforcement shall be applied in beams only and shall be a combination of stirrups and horizontal side bars: web reinforcement. When the actual shear stress (V) is less than 1.3 N/mm is required.

2

(Vc1): no web reinforcement 2

When the actual shear stress (V) is more than 1.3 N/mm (Vc1) but less than 4.5 2 2 N/mm (Vc2): web reinforcement shall be required for (V-V c1) N/mm . Where: V = Actual shear stress Vc1 = Concrete shear stress lower limit Vc2 = Concrete shear stress upper limit

10.1.2.16

♦

At least 50% of the bottom main reinforcement shall extend over the face of the support providing a good anchorage between the supports.

♦

Wind or earthquake loads shall not be combined with blast loads.

Future Load (Dead or Live Loads)

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Future loads, due to pipe rack extensions and building expansions shall be considered by CONTRACTOR. Both Pipe Racks and Building sizes as indicated in the ITT documents include a space allowance for future items. The CONTRACTOR is responsible for validating these Building and Pipe Rack sizes and the inclusion of the required percentage extra space allowance for future. The amount of future space required by COMPANY has been defined in the relevant Piping, Electrical and Instrument Specifications. With respect to the buildings, the floor and roof live loads to be applied on the future areas shall be as specified in Clause 10.1.2.4 in Specification DGS-1882-001. For pipe racks the same intensity of live load shall be applied to the future space areas as the CONTRACTOR determines for the design of adjacent areas within the same pipe rack. Regarding piperack future space allowance reference shall be made to Piping’s DGS. 11.

LOAD COMBINATIONS

11.1

Piles, structures and members of structures as well as their support and fixing points shall be designed for the various loading combinations given in the following tables: Load Description Weight of Structure Empty Weight of Vessels and Equipment Operating Load Hydrostatic Test Load Live Load Moving/Truck Load Wind Load Earthquake Load Crane/Impact Load Dynamic Load Thermal Load Erection Load Maintenance Load Differential Settlement Earth/Water Pressure Blast Load

11.2

Abbr. DL DLempty LLop Test LL LLmove WL EQ CR DY TL ER ML DS HY BL

Ref. Section 10.1.2.1 10.1.2.1 10.1.2.2 10.1.2.3 10.1.2.4 10.1.2.5 10.1.2.6 N/A 10.1.2.8 10.1.2.9 10.1.2.10 10.1.2.11 10.1.2.12 10.1.2.13 10.1.2.14 10.1.2.15

Loads shall be combined as specified below. Concrete bund walls shall be designed for accidental load condition when the bund is completely filled with water to the crest. Only the hydrostatic fluid acting in the outward direction and gravity loading need to be considered. The factor of safety shall not be less than 1.3 for this loading condition.

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ABU DHABI GAS INDUSTRIES LTD. (GASCO) STRUCTURAL DESIGN BASIS 6

Load Combinations A through G : Primary Loads

DL DLempty Test LL Crane LLop LLmove WL EQ DY TL ER ML DS HY BL

Operation without wind A x x x x x x

Test

with wind B x 1 x x

Earthquak e

Mainten ance

Blast

D x x

E x x

F X X

G x x

x x

x

X X

1

x

x x

5

x

x

x x x

C x x x x x

Erectio n

3,4

x

x

X

4

x

N/A X X

2

x

x x x

x x

x x

x

X X

x x x x

NOTES: 1.

The most unfavorable load combination shall be taken into account.

2.

Only if the structure supports rotating equipment that will be in operation while a vessel is being tested with water.

3.

Only 50% wind load shall be taken into account.

4.

The effect of wind forces acting on temporary scaffolding erected during construction, or later for maintenance, which will be transferred to the vessel or column shall be considered. When considering these effects, the actual projected area of the scaffold members together with the correct shape factor and drag coefficient should be used. As an initial approximation, the overall width of the scaffolding itself can be taken as 1.5 m on each side of the vessel or column with 50% closed surface and shape factor 1.0.

5.

Blast condition shall be taken into account for the blast resistant design of buildings where applicable.

6.

In the ultimate limit state design, due regard shall be given to the different load factors for the various load combinations and the adverse or beneficial effects of the basic load cases.

Where imposed loads (live loads) have a beneficial effect, they shall be zero. DGS-1882-001/FH

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12.

STRUCTURAL MATERIALS

12.1

GENERAL Pipe racks, process equipment structures & shelters to compressors and other equipment shall be of galvanized structural steel. The use of alternative materials such as pri cast insitu reinforced concrete for such items is not acceptable The general types of material to be used are defined below:

12.2

STRUCTURAL STEEL The furnishing, fabricating, and erecting of structural steel and miscellaneous steel shall be in accordance with Design General Specifications. Structural steel shapes and plates shall conform to ASTM A36 or to BS 4 or BS EN 10210-2 or BS en 10025.

12.3

CAST-IN-PLACE CONCRETE Cast-in-Place Concrete shall have a minimum compressive strength in accordance with Specification for Concrete Supply. DGS 1783 001. Upon the approval of COMPANY, higher strength concrete may be used. Precast concrete shall be possible with approval of COMPANY. In-situ cast or pre-cast concrete shall not be used for pipe racks, equipment support structures and shelters.

12.4

REINFORCING STEEL Requirement to prevent stray current corrosion of steel in concrete (due to implementation of impressed current CP to the nearby underground installation) is to be in accordance with Specification DGS-6300-006 – Material Selection and Corrosion Monitoring Philosophy – Clause 10.13.3. Reinforcing steel shall conform to BS 4449 Grade 460. Epoxy coating shall not be used. Welded wire fabric shall conform to BS 4483. Epoxy coatings shall not be used. For rebar electrical continuity in concrete structures refer to the Project Specification DGS-1674-001.

12.5

CONCRETE MASONRY 2

Mortar shall be Type M mortar (f’c = 17.3 N/mm ) conforming to ASTM C270. When determining allowable mortar stress, assume no inspection. 2

Concrete blocks shall be Grade A, hollow-unit concrete blocks (f’c = 9.3 N/mm ) conforming to ASTM C9O. Reinforcing steel shall conform to BS 4449 Grade 460. DGS-1882-001/FH

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12.6

ANCHOR BOLTS Anchor bolts shall conform to ASTM A36. Minimum size bolts for structural columns and typical equipment shall be 20 mm, 16 mm bolts may be used for small pumps and handrails. Anchor bolts shall be galvanized in accordance with ASTM A123 and ASTM 143. See Standard Drawing. In special cases where A36 anchor bolts are not sufficient, ASTM A193 Grade B-7 shall be used. Paint (only) for these high-strength bolts may be used upon approval of the DESIGNER.

12.7

HANDRAIL All handrail shall conform to ASTM A36. See Standard Drawing.

12.8

WELDING Welding shall conform to the AWS D1.1. All welding electrodes shall meet filler metal requirements given in AWS D1.1. The electrode material shall be E70XX.

12.9

GRATING Grating shall conform to ASTM A1011 or BS 4592. The grating size and method of attachment shall be indicated in the project specifications. Grating and fixing material (clips) shall be hot-dip galvanized in accordance with ASTM A123 and A143.

12.10

FLOOR PLATE Checkered floor plate shall be four-way, raised pattern steel plate with a thickness of 10 mm. Plate material shall conform to ASTM A36.

12.11

BOLTS The following bolts shall be used for all connections unless higher strength bolts are required and are noted on the drawings: Bolts 20 mm and larger shall be high strength ASTM A325M or A490M; Bolts 16 mm and smaller shall be in accordance with ASTM A307. Anchorage of low temperature equipment (-50C) on steel structures shall use ASTM A320.L7 bolts. Unless noted otherwise on the drawing, bolt size shall be as follows: For main members: 20 mm (min) For railings and ladders: 16 mm (refer to applicable STANDARDS) For ladder cages: 12 mm (refer to applicable STANDARDS) For stair treads: 8 mm (refer to applicable STANDARDS) High strength bolts shall be installed in accordance with AISC.

12.12

GROUTING

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All grout materials and application procedures shall be used in accordance with Specification for Grouting DGS 1783 004. 12.13

EMBEDDED ITEMS All embedded items shall be ASTM A36 material and shall be hot-dip galvanized. CONTRACTOR is to develop a detail, which effectively seals the junction of embedded items and concrete, for COMPANY approval.

13.

ALLOWABLE STRESSES

13.1

STRUCTURAL STEEL Allowable stresses specified in AISC specifications shall be used for the design of structural steel.

13.2

CAST-IN-PLACE CONCRETE The allowable stresses specified in ACI 318M shall be used in the design of concrete.

13.3

MASONRY The allowable stresses specified in ACI 530 and UBC shall be used for masonry design.

13.4

ANCHOR BOLTS AND BASE PLATE BEARING 1.

The allowable stress for anchor bolt shall conform to AISC and ACI Specifications. Neither probability factors nor allowable stress increases shall be used for anchor bolt design.

The calculated bolt diameter required to resist specified design loads shall be increased 3 mm to provide an allowance for corrosion. 2. 13.5

Permissible bearing stress under base plates shall be as given in ACI 318 Code.

STRESS INCREASE The allowable stresses specified in the applicable codes given above for structural steel, concrete, and masonry shall apply f or all design with the following exceptions: The increase in allowable stresses for all structural elements and their connections: 20% - Test without Wind Load 33% - Including Wind 1.2 -

14.

Test Load Factor for Concrete Design

DEFLECTION AND VIBRATION

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14.1

ALLOWABLE DEFLECTIONS The functional requirements of the structure may impose stricter limits. Systems should be reviewed for possible incompatible deflection behavior in piping, equipment or building components and support deflections.

14.1.1

Beam Deflections (Based on Live Loads Only).

14.1.1.1

Maximum allowable deflection for beams supporting floor systems and equipment shall be as follows: Max deflection =

14.1.1.2

L = Overhang Length

L / 300

L = Span

L / 300

L = Span

L / 600

L = Span

L / 400

L = Span

Monorails Max deflection =

14.1.3

L / 400

Overhead Traveling Max deflection =

14.1.2.2

L = Span

Crane Runways Max deflection =

14.1.2.1

L / 400

Maximum allowable deflection for beams supporting steel platforms, staircases, pipe racks, etc. Max deflection =

14.1.2

L = Span

Maximum allowable deflection for cantilever beams shall be as follows: Max deflection =

14.1.1.5

L / 360

Maximum allowable deflection for purlins supporting roof system shall be as follows Max deflection =

14.1.1.4

L = Span

Maximum allowable deflection for beams supporting brittle finishes, such as plaster ceilings shall be as follows: Max deflection =

14.1.1.3

L / 500

Lateral Sway Maximum allowable sway of buildings or structures shall be as follows: Max deflection = H / 300

H = Height - if equipment supported

H / 200 H = Height - If equipment not supported DGS-1882-001/FH

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Maximum allowable sway for pipe racks shall be as follows: Max deflection = H / 200

H = Height

Maximum allowable deflection for wall stanchions shall be as follows: Max deflection = H / 300

H = Height

h = height of story or height of structure These limits apply to sway between stories and to the structure as a whole. Grating =

L / 250 (Maximum span 1.6 meter)

14.2

VIBRATION

14.2.1

Superstructure Vibration

14.2.1.1

The primary source of vibration in superstructures is harmonic unbalanced forces generated by rotating or reciprocating equipment. The final design should be such that vibrations will be neither intolerable nor troublesome to personnel, and will not cause damage to the machine or structure or adjacent foundations, structures or services.

14.2.1.2

As a general rule, none of the natural frequencies of the structure should be within a band of the operating frequency of the supported machinery. The band recommended to be avoided is 1.414 above operating frequency and 0.707 below operating frequency. To find structural natural frequencies, a computer analysis shall be required. All natural frequencies below 2 times the operating frequency for reciprocating equipment and below 1.5 times the operating frequency for rotating equipment shall be calculated.

14.2.1.3

It shall be demonstrated that the amplitudes at the natural frequencies between 0.35 and 1.5 times the operating frequency are within the allowable values even assuming that - due to differences between the actual structure and the assumed model resonance does occur. In this case a reasonable amount of damping should be estimated.

14.2.1.4

Resonant condition requires a detailed three-dimensional dynamic analysis. Once a model analysis has been performed, a harmonic response analysis shall be performed. The response analysis will indicate anticipated amplitudes of vibration, velocity, and acceleration, as well as magnitudes of forces in structural members. From the above information, the adequacy of the design can be evaluated, and, if necessary, modifications can be made.

14.2.1.5

The maximum vibration amplitude of the equipment shall not exceed the lower of the following values:

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a.

The maximum allowable values stated by the manufacturer of the equipment.

b.

The amplitude (single amplitude) which causes the effective velocity of vibration to exceed:

2 mm/s at the location of the machine-bearing housings 2.5 mm/s at any location of the structure c.

The dynamic amplitude of any part of the foundation including any reciprocating -3 compressor shall be less than 80 µm single amplitude (80 x 10 mm).

NOTE: The effective velocity is defined as the square root of the average of the square of the velocity, velocity being a function of time. In the case of a pure sinusoidal function the effective velocity is 0.71 times the peak value of the velocity. 14.2.1.6

The depth of a steel beam supporting large open floor areas free of partitions or other sources of damping should not be less than 1/20 of the span to minimize perceptible transient vibration due to pedestrian traffic.

14.2.2

Foundation Vibration.

14.2.2.1

The DESIGNER shall determine which vibrating equipment is to be analyzed by dynamic analysis.

14.2.2.2

Dynamic Analysis For foundations for reciprocating machinery, centrifugal machinery and centrifugal pumps 750 kW or over, a three dimensional dynamic analysis must be performed. Foundation vibration generally involves a grade foundation designed to support one or more reciprocating or rotating machines. Generally the same considerations for superstructure vibration also apply to foundation vibration. The primary differences are that these foundations are often rigid blocks and that soil behavior must be considered. Rigid foundations supporting only one major machine can readily be analyzed using hand calculations and the concept of elastic half-space theory. For flexible foundations or foundations with many machines, a computer analysis should be utilized along with the concept of elastic half-space theory. The DESIGNER shall prepare an instruction for foundation vibration analysis which contains current state-of-the-art approaches, soil information, machine information, dynamic analysis aids, published response criteria, example solutions, and a comprehensive list of references. The dynamic amplitudes of any part of the foundation including any reciprocating -3 compressor shall be less than 80 µm (80 x 10 mm) single amplitude. For the dynamic analysis, the exciting forces shall be taken as the maximum values that, according to the MANUFACTURER of the equipment, will occur during the lifetime of the equipment. When the exciting force is not given by the MANUFACTURER, it shall be determined from Q(kN) = [Rotor Speed (rpm)/6000] x Rotor Weight (kN)

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The dynamic calculations shall be based on a mechanical model wherein the weights and elasticity of both structure and foundation and the weight of the equipment are represented in an appropriate way. All natural frequencies below 2 times the operating frequency for reciprocating equipment and below 1.5 times the operating frequency for rotating equipment shall be calculated. It shall be demonstrated that the amplitude of the natural frequencies between 0.35 and 1.5 times the operating frequency are within the allowable values even assuming that - due to differences between the actual structure and the assumed model resonance does occur. In this case, a reasonable amount of damping should be estimated. The natural frequency of the supporting structure shall not coincide with any resonant frequency of the equipment. The static deformation for rotating equipment foundations shall be calculated and shown to be within the limits stated by the MANUFACTURER of the equipment. The calculations shall include, but not be limited to, the following causes of def ormation.

14.2.2.3

♦

Shrinkage and creep of concrete.

♦

Temperature effects caused by radiation and convection of heat or cold generated by machinery, piping, and ducting.

♦

Elastic deformation caused by changing vapor pressure in condensers.

♦

Elastic deformation caused by soil settlement.

Non-Dynamic Analysis For installations that do not warrant a dynamic analysis, (equipment weight less than 50 kN), the mass ratio concept is commonly used. In the design of equipment foundations subject to vibratory loading where dynamic analysis is not performed, foundations shall be proportioned as indicated below: Rotating equipment mass ratio = weight of concrete / weight of machine > 3 Reciprocating equipment mass ratio = weight of concrete / weight of machine > 6

14.2.2.4

Foundations for heavy machinery subjected to unbalanced dynamic forces shall be kept independent of building floors and other equipment foundations.

15.

MISCELLANEOUS DESIGN DATA

15.1

CLEARANCES AND ACCESSIBILITY

15.1.1

Minimum clearances for Equipment, Structures, Platforms and Supports shall be in a accordance with the table in Specification for Design, Layout and Drawing DGS 1300 040.

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15.2

COEFFICIENTS OF STATIC FRICTION Coefficients of static friction for various material combinations are listed as follows:

15.2.1

Steel to steel Smooth, dry surfaced

0.3

Oxidizing steel

0.5

15.2.2

Steel to concrete or grout

0.5

15.2.3

Fluorogold, Teflon, and other similar materials MANUFACTURER'S recommendations

15.2.4

Concrete to foundation materials Clean sound rock

7

Clean gravel, gravel-sand mixtures, coarse sand

0.55

Clean fine to medium sand, silty medium to coarse sand, silty or clay gravel

0.45

Clean fine sand, silty or clayey, fine to medium sand

0.35

Fine sandy silt, nonplastic silt

0.30

Very stiff and hard residual or preconsolidated clay

0.40

Medium stiff and stiff clay

16.

and silty clay

0.30

Membrane sheet

0.20

ENGINEERING MAINTENANCE MANUAL The DESIGNER shall prepare a detailed maintenance manual for use by the operators. The manual shall contain the f ollowing information:

16.1

DESIGN BASIS A brief description of the basis of design of all foundations, structures and buildings, including reference to the detailed calculations for each to enable them to be retrieved

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if necessary. 16.2

INSPECTION Recommendations for the routine inspection of works to enable the early detection of potentially dangerous deterioration, including guidelines regarding the symptoms to be looked for, such as locations and types of cracking which could be found in reinforced concrete structures, etc. Routine forms for inspection are to be established.

16.3

MATERIALS A detailed listing of all materials used (both generic types, and MANUFACTURERS' details) in the works, including concrete mix constituents, concrete surface coatings, steel grades, painting details, etc., to enable the COMPANY to obtain compatible materials for future maintenance.

16.4

MAINTENANCE AND REPAIR PROCEDURES Details of recommended repair procedures for common types of failure, such as breakdown or mechanical damage to concrete surface coatings, cracking of small foundations plinths due to reinforcement corrosion, etc.

16.5

FINISHING MATERIAL MANUAL Additional list of all finishing materials used in the project buildings including material catalogs and sources to enable the COMPANY to obtain such material or equal for future maintenance.

17.

OPERATIONAL REQUIREMENTS

17.1

CONCRETE ASSET MANAGEMENT SYSTEM (CAMS) In view of the continuous deterioration of reinforced concrete structures in plants, a computerized database system has been developed by the COMPANY to carry out periodical inspections and monitor the evaluation of disorder, if any. Data related to new structures/foundations is required to be entered by the CONTRACTOR in the system in accordance with the existing procedure.

17.2

EXISTING SETTLEMENT CHECK SURVEY PROGRAM An existing computerized monitoring system for tanks and critical foundations carrying large loads, rotating equipment foundations, etc, has been developed by the COMPANY. As a result of this ongoing program, new tanks and critical foundations are required to be monitored for future maintenance. The CONTRACTOR is required to provide the following:

DGS-1882-001/FH

DGS-1882-001-Structural Design Basis.pdf

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