Tutorial - Soil Overburden and Seismic Wave Propagation in AutoPIPE v9_5

Description: Soil Overburden and Seismic Wave Propagation Product: AutoPIPE Version Number: V8i (v9.5) Submitted By: JT Revision: 0.0 Table of Contents TABLE OF CONTENTS ........................................................................................................................................................ 1 ASSIGNING SOIL PROPERTIES TO BURIED PIPING .............................................................................................................. 3 INTRODUCTION............................................................................................................................................................................ 3 FURTHER INFORMATION ................................................................................................................................................................ 3 WORK FLOW – ASSIGNING SOIL PROPERTIES .................................................................................................................................... 4 NEW INPUTS IN AUTOPIPE V9.5 .................................................................................................................................................... 4 SOIL OVERBURDEN LOADS ............................................................................................................................................... 5 WORK FLOW – SOIL OVERBURDEN LOADS ........................................................................................................................................ 5 OPEN AUTOPIPE MODEL.............................................................................................................................................................. 6 ADDING GAPS/FRICTION/SOIL ....................................................................................................................................................... 7 SELECT A RANGE .......................................................................................................................................................................... 8 SOIL PROPERTIES DIALOG .............................................................................................................................................................. 9 EDIT SOIL PROPERTIES DIALOG ..................................................................................................................................................... 10 SOIL OVERBURDEN LOADS DIALOG ................................................................................................................................................ 11 BURIED PIPE RESULT OPTIONS DIALOG ........................................................................................................................................... 13 GENERATE BATCH REPORT........................................................................................................................................................... 14 SEISMIC + THERMAL LOAD CASE ..................................................................................................................................... 16 WORK FLOW – SEISMIC THERMAL LOAD CASE ................................................................................................................................ 16 OPEN AUTOPIPE MODEL............................................................................................................................................................ 17 ADDING GAPS/FRICTION/SOIL ..................................................................................................................................................... 18 SELECT A RANGE ........................................................................................................................................................................ 19 SOIL PROPERTIES DIALOG ............................................................................................................................................................ 20 EDIT SOIL PROPERTIES DIALOG...................................................................................................................................................... 21 SEISMIC WAVE DATA DIALOG ....................................................................................................................................................... 22 SEISMIC THERMAL LOAD ............................................................................................................................................................. 24 ADDING A SAM CASE ................................................................................................................................................................. 25 BURIED PIPE RESULT OPTIONS DIALOG ........................................................................................................................................... 27 CODE COMBINATIONS ................................................................................................................................................................ 28 GENERATE BATCH REPORT........................................................................................................................................................... 29 BUILDING SETTLEMENT .................................................................................................................................................. 31

Page 1

WORK FLOW – BUILDING SETTLEMENT .......................................................................................................................................... 31 OPEN AUTOPIPE MODEL............................................................................................................................................................ 32 ADDING GAPS/FRICTION/SOIL ..................................................................................................................................................... 33 INSERT IMPOSED DISPLACEMENT .................................................................................................................................................. 33 DEFINE LOADS AND RUN ANALYSIS................................................................................................................................................ 35 BURIED PIPE RESULT OPTIONS DIALOG ........................................................................................................................................... 36 CODE COMBINATIONS ................................................................................................................................................................ 37 GENERATE BATCH REPORT........................................................................................................................................................... 38 ASME NC/ND – ADAMS ET. AL. STRESS SUMMARY ......................................................................................................... 39 WORK FLOW – ASME NC/ND ADAMS ET. AL. SUMMARY ................................................................................................................ 39 OPEN AUTOPIPE MODEL............................................................................................................................................................ 40 ADDING GAPS/FRICTION/SOIL ..................................................................................................................................................... 41 SELECT A RANGE ........................................................................................................................................................................ 42 APPLY SOIL LOADS ..................................................................................................................................................................... 43 ADDING A THERMAL LOAD CASE ................................................................................................................................................... 46 BURIED PIPE RESULT OPTIONS DIALOG .......................................................................................................................................... 47 COMBINATIONS DIALOG .............................................................................................................................................................. 48 CREATE ADAMS ET. AL. STRESS SUMMARY ...................................................................................................................................... 49 GENERATE BATCH REPORT........................................................................................................................................................... 50 MISCELLANEOUS INFORMATION .................................................................................................................................... 51 VIEW SOIL PROPERTIES ............................................................................................................................................................... 51 LOAD COMBINATION DIALOG ....................................................................................................................................................... 52 BURIED PIPE RESULT OPTIONS DIALOG ........................................................................................................................................... 53 SOIL OVERBURDEN CATEGORIES ................................................................................................................................................... 53 SEISMIC + THERMAL CATEGORY .................................................................................................................................................... 53 BUILDING SETTLEMENT CATEGORY ................................................................................................................................................ 54 SOIL OVERBURDEN STRESSES APPLICATION ON AUTOPIPE PIPING POINTS............................................................................................ 54 BUOYANCY FORCE EXERTED ON BURIED PIPING ............................................................................................................................... 55

Page 2

Assigning Soil Properties to Buried Piping Introduction The analysis of a buried piping system requires special modeling consideration. This is because the restraint (support) provided by soil surrounding a buried pipe is continuous. As AutoPIPE analysis is based on discretely defined points, so an accurate model of the soil's restraint capabilities would require the definition of a number of closely spaced piping points. Each soil point would then require a set of support springs which model the stiffness(es) provided by the soil at that point. In AutoPIPE, user can select a range of pipeline and assign soil stiffness properties in four directions and soil spring spacing for that range. Three sets of soil stiffness values can be assigned per soil identifier, which enables the user to define a low bound, average, and high bound stiffness values. In addition, AutoPIPE also has built in soil stiffness calculator, which automatically calculates soil stiffness values based on soil properties entered by the user. Two methods for calculating the soil properties i.e. AutoPIPE, and ASCE 2001 w/2005 addenda are provided. Moreover, A simplified tool for calculating virtual anchor length has also been provided. In AutoPIPE version 9.5, additional capabilities for calculating stresses in a buried piping due to the soil load on top of pipe, soil overburden loads like traffic loads, ring buckling, effect of seismic wave propagation, and building settlement effects. The workflows and additional information for calculating these stresses has been detailed in this tutorial.

Further Information For further information on how to insert soil properties to a pipe sections, refer to online help "Help > Reference Information > PipeSOIL" and "Modeling Approaches > Example Systems > PIPE-SOIL Interaction: Transition Example”. You can always press the Help button on each dialog for specific information.

Page 3

Work Flow – Assigning Soil Properties Create a new model or open Existing AutoPIPE Model

Select pipe range for inserting Soil Properties

Open Soil Properties dialog (Insert > Soil Properties) and click on Enter Soil Properties

Modify Soil input Parameters on the Edit Soil Properties dialog, and generate soil stiffness values

New Inputs in AutoPIPE v9.5 In AutoPIPE version 9.5, a couple of new input parameters are added to the Soil Parameters input grid. These are marked with an asterisk (*) to highlight that these inputs are required for calculation of additional stresses only. Height of water on top of pipe is used for calculation of submerged soil weight and buoyancy force exerted on pipe. Soil Adhesion is used in calculation of equivalent temperature dT due to seismic wave propagation. Other additional inputs added in AutoPIPE version 9.5 will be discussed in the sections below.

Page 4

Soil Overburden Loads Work Flow – Soil Overburden Loads Open Existing AutoPIPE Model

Add Non-Linear Option in the Static Analysis dialog

Select pipe range for Soil Properties

Open Soil Dialog (Insert > Soil Properties) and generate soil stiffness values

Open Edit Soil Properties dialog and click on Soil Overburden Loads

Analyze the model and open the Buried Pipe Result Options (Tools > Model Options > Buried Pipe Results..." dialog to select options related to Soil Overburden Categories

Generate batch output report and review results

Page 5

Open AutoPIPE Model Open Model “SOILOVERBURDEN_1.DAT”

Page 6

Adding Gaps/Friction/Soil In order to avoid any inconsistencies in the model, add Gaps/Friction/Soil by opening the Analysis Set dialog (Load > Static Analysis) and modifying the first Analysis Set No.

Click OK on both windows, and when it asks if the analysis should be run, click No. Note: Important to generate the seismic wave propagation thermal case before running the static analysis

Page 7

Select a Range Select the range A04 N+ to A07. This will be used to apply the soil load.

Page 8

Soil Properties Dialog   

Open Soil Properties dialog through Insert > Soil Properties Define the Soil ID to APIP_H and Maximum Spacing to the default 80 inches Click the Enter Soil Properties button

Page 9

Edit Soil Properties Dialog For further explanation of how soil stiffness properties are generated, please refer to "Online Help > Reference Information > PipeSOIL" and "Online Help > Modeling Approaches > Example Systems > PIPE-SOIL Interaction: Transition Example". Soil stiffness values can be generated by changing the Calculation Method and pressing the Generate command button.   

Note the default Soil Parameters; these values will be used to apply the soil load to the piping Click on the Generate button to fill out the k1, p1, and k2 values Click on the Soil Overburden Loads button to open Soil Overburden Loads dialog

Page 10

Soil Overburden Loads Dialog All parameters need to be defined. Note that this dialog is only available for B31.1 (2004 or later) and ASME NC/ND (2004 or later). The Pipe Identifier is required to be selected so that user can refer to which pipe ID’s are used on the previous dialog Edit Soil Properties in front of f. When displaying the soil overburden stress f in the output report, AutoPIPE automatically uses the required pipe properties at each point. Pressure on pipe due to surface load depends on the Surface Live Load Type dropdown box, and can be zero. Three surface load files (Highway-H20, Cooper-E80, and Airport-180) with pressure values at different depths taken from ASCE 2001 are provided by default. Users can create custom live surface load files by entering values of pressure on pipe due to external loads on different depths below ground. The format of the file needs to be the same as the other "*.SLD" files shipped with AutoPIPE. The Trench Laying conditions are taken from ANSI AWWA C150 and the values of Modulus of passive soil fill reaction E', Bending moment coefficient Kb and Deflection coefficient Kx are defaulted to the values for AWWA C150 when trench laying condition is changed. The last four entries are dependent on which calculation method has been chosen. The default is “Adams et. al.,” however “ASCE 2001” and “AWWA C150” can be selected in the Buried Pipe Result Options dialog. The Buried Pipe Result Options dialog must also be used to include the Soil Overburden Loads in code compliance of the output report.   

Change the Surface Live Load Type to “Airport-180k” Accept the defaults by clicking OK The value for f should now be 17431 psi. Click OK in the Edit Soil Properties dialog and Soil Properties dialog.

Page 11

Page 12

Perform Analysis 

Run the analysis (Analyze > Analyze All)

Buried Pipe Result Options dialog Note the default values in the Soil Overburden Categories section of the dialog. The calculation methods available are Adams et.al. AWWA C150 and ASCE 2001. The soil input parameters allow the user to select what values of the Soil Parameters from the Edit Soil Properties dialog are used.  

Open the Buried Pipe Result Options dialog (Tools > Model Options > Buried Pipe Result Options) Before accepting changes, be sure to check the Display circ. Wall bending & ring buckling in code compliance so the results of the soil overburdening is displayed in the output

Page 13

Generate Batch Report Selecting Code Compliance allows the user to see the Circumferential Wall Bending Stress and Ring Buckling Pressure with allowable value.  

Open Batch Report dialog through Result > ‘Output Report…’ Include ‘Code Compliance’ as a section to review

Review the results at each point in the batch output report:

Page 14

The file SOILOVERBURDEN_2.DAT is included and contains the final result of this.

Page 15

Seismic + Thermal Load Case Work Flow – Seismic Thermal Load Case Open Existing AutoPIPE Model

Assign soil IDs to buried piping points entering soil properties for each soil ID and generate soil stiffness values

For each soil ID, also assign the Seismic Wave Data using Seismic Wave Data dialog.

Generate seismic wave propagation equivalent thermal case(s) using the Generate Seismic Thermal Load Case (Load > Seismic Thermal Load)

Analyze the model and open the Buried Pipe Result Options ("Tools > Model Options > Buried Pipe Results...") dialog to assign options related to Seismic + Thermal Categories

Generate the code compliance report to see the seismic + thermal stresses due to the combined effect of seismic wave propagation, seismic anchor movement, and operating temperature cases

Page 16

Open AutoPIPE Model Open Model “SEISMICTHERMAL_1.DAT” Note that for this model two thermal load cases have been created. 1. A seismic wave propagation equivalent thermal case which will be combined with a SAM case to give you the Seismic part in the Seismic + Thermal load combination 2. An operating thermal case which gives you the Thermal part in the Seismic + Thermal load combination

Page 17

Adding Gaps/Friction/Soil In order to avoid any inconsistencies in the model, add Gaps/Friction/Soil by opening the Analysis Set dialog (Load > Static Analysis) and modifying the first Analysis Set No.

Click OK on both windows, and when it asks if the analysis should be run, click No. Note: Important to generate the seismic wave propagation thermal case before running the static analysis

Page 18

Select a Range Select the range A04N to A07. This will be used to apply the soil load.

Page 19

Soil Properties Dialog   

Open Soil Properties dialog through Insert > Soil Properties Define the Soil ID to APIP_H and Maximum Spacing to the default 80 inches Click the Enter Soil Properties button

Page 20

Edit Soil Properties dialog Note the default Soil Parameters. These values will be used to apply the soil load to the piping. For further explanation of how soil stiffness properties are generated, please refer to "Online Help > Reference Information > PipeSOIL" and "Online Help > Modeling Approaches > Example Systems > PIPE-SOIL Interaction: Transition Example". Soil stiffness values can be generated by changing the Calculation Method and Soil Type and then pressing the Generate command button.   

Leave the Calculation Method as default and click on the Generate button to fill out the k1, p1, and k2 values Check to see that the new values at the bottom of the dialog are the same as the image below Click on the Seismic Wave Data button to open the Seismic Wave Data dialog

Page 21

Seismic Wave Data dialog All parameters need to be defined. Seismic wave type affects seismic wave coefficient aw and seismic wave curvature coefficient ak. Note that this dialog is only available for B31.1 and ASME NC/ND years 2004 and higher.

    

Check Assign seismic wave data above to all Soil Identifiers Click OK Click Yes to confirm that you wish to apply this data to all soil identifiers The value of dT on the Edit Soil Properties dialog should now read 72.507 deg F Close both dialogs by clicking OK

The Pipe Identifier is required to be selected so that user can refer to which pipe ID’s are used on the previous dialog Edit Soil Properties in front of dT. When calculating the temperature using the Generate Seismic Thermal Load Case, AutoPIPE automatically uses required pipe properties at each point.

Page 22

The strains generated in the pipe due to seismic wave propagation are calculated and using these strain values, an equivalent temperature dT is calculated using coefficient of expansion for the material α. Ambient temperature is added to dT to reflect the effects of this temperature rise. This temperature can then be added to a temperature case to simulate the effects of seismic wave propagation. AutoPIPE calculates coefficient of expansion values based on expansion values of the material at ambient temperature + 10 deg F. In case of non standard (NS) material, the expansion values are not available from the library. In this case AutoPIPE uses the expansion value for steel taken as 6.5E-6 in/in/deg F. AutoPIPE calculates both axial and bending strains due to wave propagation and takes the maximum of two values. However, if the Add axial and bending strain for calculation of temperature is checked, both the strains are added for calculating temperature. If the Seismic data is the same for all soil IDs, you can define seismic data for one soil ID and use "Assign seismic wave data above to all Soil Identifiers" option to set the same seismic data for all soil identifiers. The final value for dT should be 72.507 deg F.

Page 23

Seismic Thermal Load An existing thermal load case can be modified by selecting it as Thermal load case to modify. AutoPIPE will overwrite the temperatures at piping points for selected thermal load case with the calculated seismic wave equivalent temperature depending on the different options on the dialog. This temperature case can then be used in Seismic+Thermal category to be combined with the SAM case as required by Adams method. AutoPIPE calculates both axial and bending strains due to wave propagation and takes the maximum of two values. However, if the Add axial and bending strain for calculation of temperature is checked, both the strains are added for calculating temperature.  

Open the Generate Seismic Thermal Load Case dialog through Load > Seismic Thermal Load Click OK to accept the default values

The temperature change from this dialog is shown below.

Page 24

Adding a SAM Case Add a SAM case to the model.     

Apply an Imposed Displacement (Insert > Xtra Data) of 5 inches in the –Y direction on point A06 Set the Load case combine with to S1 and ensure that the Support Group No. is set to 1 Apply a SAM to the Support Group No. by opening the SAM / MSRS Support Group dialog (Insert > SAM/MSRS Support Group) Accept the default values Finally, run the SAM Analysis (Analyze > Seismic Anchor Movement)

Page 25

Page 26



Buried Pipe Result Options dialog In order to activate the Display seismic + thermal combination in code compliance, both Thermal case used for seismic wave propagation load and SAM case combined with seismic wave propagation must have valid cases selected. Any SAM case that is available and analyzed can be selected as the SAM case combined with seismic wave propagation. Select T1 and S1, respectively. The Thermal case used for seismic wave propagation load should be selected as the temperature case which has the equivalent seismic wave propagation temperature values assigned to it at each point. Other operating thermal cases will then be automatically combined with these two load cases to generate default combinations as per Adams method.   

Open the Buried Pipe Result Options dialog (Tools > Model Options > Buried Pipe Result Options) Select T1 and S1 for Thermal case used for seismic wave propagation load and SAM case combined with seismic wave propagation, respectively Check Display seismic + thermal combination in code compliance and click OK

Page 27

Code Combinations Open the Load Combination dialog (Tools > Combinations). Click on the Code Comb. tab and ensure that WavePR+SAM and Seismic + T2 are shown.

If Seismic + T2 does not show, open the Analysis Sets dialog (Load > Static Analysis Sets) and modify the first Analysis Set No. to make sure that T2 is selected. If it is not, select it and re-run the Analysis (Analyze > Analyze All). Recheck the Load Combination dialog to see the new combination.

Page 28

Generate Batch Report   

Open Batch Report dialog through Result > ‘Output Report…’ Include ‘Code Compliance’ as a section to review Seismic + Thermal combinations Click OK to review the output report


Page 29

The file SEISMICTHERMAL_2.DAT contains the final result of this tutorial.

Page 30

Building Settlement Work Flow – Building Settlement Create ASME B31.1-2010 model and insert piping components

Insert Imposed Support Displacement (Insert > Xtra Data > Imposed Support Displacement...)

Analyze the model and open the Buried Pipe Result Options (Tools > Model Options > Buried Pipe Results...") dialog to assign options related to building settlement

When the "Buil Sett" option in Buried Pipe Result Options is checked then the combination dialog will display the additional category for ring buckling


Page 31

Open AutoPIPE Model Open the “BuildingSettlement_1.DAT” model.

Page 32

Adding Gaps/Friction/Soil In order to avoid any inconsistencies in the model:   

Add Gaps/Friction/Soil by opening the Analysis Set dialog (Load > Static Analysis) and modifying the first Analysis Set No Click OK on both dialogs When it asks if the analysis should be run, click No

Note: Important to generate the seismic wave propagation thermal case before running the static analysis

Insert Imposed Displacement By inserting an imposed displacement as a user case, it is possible to display the building settlement category in code compliance. Place an imposed displacement at A07 (should be the final anchor in the model).    

Open the Imposed Support Displacements dialog through Insert > Xtra Data > Imposed Support Displacement. Set Load case to combine with to U1 Set Y-translation to -5.0 inches Click OK to close the dialog

Page 33

Page 34

Define Loads and Run Analysis  

Open the Analysis Sets dialog (Load > Static Analysis Sets) and modify Analysis set No. 1 to include U1 for analysis Click OK and run the analysis

Page 35

Buried Pipe Result Options dialog    

Open the Buried Pipe Result Options dialog through Tools > Model Options > Buried Pipe Result Options In the Building Settlement Category section, select user case 1 Check the Display building settlement category in code compliance box below it Click OK to close the dialog and accept changes

Page 36

Code Combinations   

Open the Load Combinations dialog through Tools > Combinations Note the “Buil Sett U1{1}” entry under the Code Comb. tab. Click OK to close the dialog

Page 37

Generate Batch Report  

Open Batch Report dialog through Result > ‘Output Report…’ Include ‘Code Compliance’ as a section to review Building Settlement combination


The file BUILDINGSETTLEMENT_2.DAT contains the final result of this tutorial.

Page 38

ASME NC/ND – Adams et. al. Stress Summary Work Flow – ASME NC/ND Adams et. al. Summary Create ASME NC/ND - 2007 model and insert piping components

Assign soil IDs to buried piping points entering soil properties for each soil ID. Assign Soil Overburden loads, and Seismic Wave data. Also assign SAM loading if required

Generate seismic wave propagation equivalent thermal case(s) using the Generate Seismic Thermal Load Case (Tools > Generate Seismic Thermal Categories Case)


Page 39

Open AutoPIPE Model Open Model “ADAMS_SUMMARY_1.DAT” Note that there are two temperature load cases in this model.

Page 40

Adding Gaps/Friction/Soil In order to avoid any inconsistencies in the model:  

Add Gaps/Friction/Soil by opening the Analysis Set dialog (Load > Static Analysis) and modifying the first Analysis Set No Click OK on both windows, and when it asks if the analysis should be run, click No

Note: Important to generate the seismic wave propagation thermal case before running the static analysis

Page 41

Select a Range Select the range A04 N+ to A07. This will be used to apply the soil load.

Page 42

Apply Soil Loads    

Open the Soil Properties dialog (Insert > Soil Properties) Create a soil ID named APIP_H Accept the default spacing of 80 inches Click the Enter Soil Properties button

        

Note the default soil parameters Click the Generate button Then click the Soil Overburden Loads button Change the Surface Live Load Type to Airport-180k Click OK to close the dialog and accept the defaults Click on the Seismic Wave Data button Check the box Assign seismic wave data to all Soil Identifiers Accept the defaults by clicking the OK button Click the Yes button on the popup.

The Edit Soil Properties dialog should have the same f and dT values as seen below.

Page 43

  

Accept the dialog changes and return to the model Insert an imposed displacement (Insert > Xtra Data > Imposed Displacement) Add a 5 inch displacement in the –Y direction on Load case S1 and U1 to points A06 and A07, respectively.

Page 44

 

 

Apply a SAM case to the A06 point, by opening the SAM / MSRS Support Group (Insert > SAM/MSRS Support Group) Run the SAM analysis (Analyze > Seismic Anchor Movement)

Add U1 case to the analysis through the Static Analysis Load Cases dialog (Load > Static Analysis) by modifying the first Analysis Set No. Click No when AutoPIPE asks if you want to analyze the model

Page 45

Adding a Thermal Load Case    

Generate the thermal load case by opening the Generate Seismic Thermal Load Case (Load > Seismic Thermal Load) Check the Add axial and bending strain for calculation of temperature Accept the other defaults by clicking OK Notice the changes in the T1 load case in the Review Components Data dialog afterwards

Page 46



Buried Pipe Result Options Dialog   

Open the Buried Pipe Results Option dialog (Tools > Model Options > Buried Pipe Results Options) Notice that most of the fields do not apply in ASME NC/ND and are disabled Update the fields as seen below and accept the changes.

Page 47

Combinations dialog   

Open the Load Combinations dialog through Tools > Combinations Navigate to the User Allowable tab and notice the different combinations Close the dialog by clicking OK.

Page 48

Create Adams et. al. Stress Summary Now you can select an operating thermal case, an equivalent seismic Thermal Case and a SAM load case, which will all be combined to generate the Seismic + Thermal combination as per Adams et. al. method. The Circumferential Wall Bending Stress and Ring Buckling pressure would be displayed for each buried point automatically.      

Open the Stress Summary dialog through Tools > Stress Summary Create a new Stress Summary by clicking the New command button Set the Service Level to C. Note that the Service Level will not affect any of the Adams et. al. stress summary values Select the Buried Piping as Adams et. al. Set Thermal Load Case to T1, Seismic Thermal Case to T2, and SAM Load Case to S.A.M. 1 Make sure that the Print check box is selected, and click OK to accept changes.

Page 49

Generate Batch Report  

Open Batch Report dialog through Result > ‘Output Report…’ Include ‘Stress Summary" as a section to review Adams et. al. stress summary.


The file ADAMS_SUMMARY_2.DAT contains the final result of this tutorial. Page 50

Miscellaneous Information View Soil Properties After opening the Show Options dialog (View > Show Options…), select the Soil Properties… option and click OK. AutoPIPE will prompt for a specific soil ID, or all of them. Select which one and accept. AutoPIPE will display what pipe sections contain soil properties.

Page 51

Load Combination Dialog After ‘ring buckling ’, ‘seismic + thermal’ or ‘building settlement’ case is enabled in the Buried Pipe Result Options dialog, the Code Combinations tab in the Load Combinations dialog (Tools > Combinations) will display the ring buckling as a combination.

The Adam method for NC/ND does not use the Code Comb. tab, but rather uses the Stress Summary dialog (Tools > Stress Summary).

Page 52

Buried Pipe Result Options dialog Here, you can change what soil overburden calculations are to be done, as well as seismic and thermal category and building settlement category. To open this dialog, go to Tools > Model Options > ‘Buried Pipe Results Options…’

Soil Overburden Categories The first dropdown box the calculation method can be selected, which includes Adams et.al, AWWA C150 and ASCE 2001. This directly affects the results produced. It also dictates which values in the Soil Overburden Loads dialog are used. The next dropdown box is the set of data values required for calculation in soil overburden loads and through wall bending stresses. These values can be seen in the Edit Soil Properties dialog. Adding circular bending stress to Sustained will consider bending stress along with sustained stress. Ring buckling allowable safety factor is applied to results as a factor of ring buckling allowable. In order to include soil overburden load combinations in the output report, the Display checkboxes must be checked (i.e. Display circ. Wall bending & ring buckling in code compliance)

Seismic + Thermal Category The first dropdown is used to select which temperature case the seismic wave propagation load is to be applied. A SAM case can also be applied, which, if both boxes are selected, allows the Display seismic + thermal combinations in code case check box to enable. Seismic + thermal allowable safety factor is applied to results as a factor of ring buckling allowable.

Page 53

Building Settlement Category Building settlement load case dropdown box displays all available user cases that the building settlement load can be applied. See Add Building Settlement for details.

Soil Overburden Stresses Application on AutoPIPE Piping Points Soil overburden stresses (circumferential wall bending stress, and ring buckling) are applied on all intermediate soil points (i.e. +1, +2, etc.). An explanation of soil overburden stresses for AutoPIPE piping points other than intermediate soil points is as below:

The model displayed above contains nine (09) piping control points and four soil IDs (SOILA, SOILB, SOILC, and SOILD). The intermediate soil points are not displayed in the snapshot above, and these intermediate soil points will always have soil overburden stresses defined based on the soil ID defined for the preceding piping point. The range on which each soil ID is assigned is highlighted with the legend displaying the color for each soil ID. AutoPIPE B31.1 (2004 and onwards) and ASME NC/ND (2004 and onwards) will display soil overburden stresses in code compliance report and Adams et. al. stress summary report based on reporting and calculation methods selected. The soil overburden stresses for different piping points and ranges will be displayed depending on applicable soil ID as below: Point / Range

Soil ID used for soil overburden

Comments

Page 54

A00 A01 to A02 N-

stress calculations None SOILA

A02 N+ to A02 F+ A03

None

A04 to A05 N-

None

A05 N+ to A05 F-

SOILC

SOILB

A05 F+ to A07 F- None A07 F+ to A09 SOILD

Minus face of bend near point will display soil overburden stresses due to SOILA

All intermediate soil points following A03 will have soil overburden stresses based on SOILB If there are no faces (minus, plus) for a piping run point, the second point will not have soil overburden stresses. This will assure a consistency if there is a different soil ID (say SOILX) defined on the range A04 to say A05 N-, in which case A04 will have soil overburden stresses due to SOILX. When there are two faces (minus, plus) on a piping point, the minus (-) face will calculate soil overburden stresses based on preceding point soil ID, and the plus (+) face will calculate soil overburden stresses based on current point (range) soil ID. A05 F+ will not have any soil overburden stresses Last point in the segment will have stresses due to soil overburden based on preceding point soil ID.

Currently, AutoPIPE does not assign different faces to a piping point based on change in soil ID.

Buoyancy Force Exerted on Buried Piping AutoPIPE requires user to input *Height of water on top of pipe in the Edit Soil Properties dialog for buried piping. If the buoyancy forces acting on the pipe due to ground water in the upward direction exceed the net downward forces of the pipe due to pipe weight, this force is reported in the model input listing for soil. The pipe identifier used in this case is the pipe identifier last selected in the Soil Overburden Loads dialog. If the net force acts in the downward direction, AutoPIPE reports the buoyancy force on pipe as zero.

Page 55

User may apply a net upward force due to buoyancy in AutoPIPE using the command Insert > Distributed Loads.

Page 56

Tutorial - Soil Overburden and Seismic Wave Propagation in AutoPIPE v9_5

Recommend Documents