Tutorial - Soil Overburden and Seismic Wave Propagation in AutoPIPE
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Transcript of Tutorial - Soil Overburden and Seismic Wave Propagation in AutoPIPE
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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 ................................................................................................... 3INTRODUCTION.............................................................................................................................................................. 3
FURTHER INFORMATION .................................................................................................................................................. 3
WORK FLOWASSIGNING SOIL PROPERTIES ...................................................................................................................... 4
NEW INPUTS IN AUTOPIPEV9.5 ...................................................................................................................................... 4
SOIL OVERBURDEN LOADS ..................................................................................................................................... 5
WORK FLOWSOIL OVERBURDEN LOADS .......................................................................................................................... 5
OPEN AUTOPIPEMODEL................................................................................................................................................ 6
SELECT A RANGE ............................................................................................................................................................ 7
SOIL PROPERTIES DIALOG ................................................................................................................................................ 8
EDIT SOIL PROPERTIES DIALOG ......................................................................................................................................... 9SOIL OVERBURDEN LOADS DIALOG .................................................................................................................................. 10
RUN ANALYSIS AND OPEN BURIED PIPE RESULT OPTIONS DIALOG ......................................................................................... 12
GENERATE BATCH REPORT............................................................................................................................................. 14
SEISMIC + THERMAL LOAD CASE .......................................................................................................................... 15
WORK FLOWSEISMIC THERMAL LOAD CASE .................................................................................................................. 15
OPEN AUTOPIPEMODEL.............................................................................................................................................. 16
SELECT A RANGE .......................................................................................................................................................... 17
SOIL PROPERTIES DIALOG .............................................................................................................................................. 18
EDIT SOIL PROPERTIES DIALOG ........................................................................................................................................ 19
SEISMIC WAVE DATA DIALOG ......................................................................................................................................... 20SEISMIC THERMAL LOAD ............................................................................................................................................... 21
RUN ANALYSIS AND OPEN BURIED PIPE RESULT OPTIONS DIALOG ......................................................................................... 22
GENERATE BATCH REPORT............................................................................................................................................. 22
BUILDING SETTLEMENT........................................................................................................................................ 24
WORK FLOWBUILDING SETTLEMENT ............................................................................................................................ 24
INSERT IMPOSED DISPLACEMENT .................................................................................................................................... 25
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ANALYZE MODEL AND ADD BUILDING SETTLEMENT ............................................................................................................ 25
GENERATE BATCH REPORT............................................................................................................................................. 26
ASME NC/NDADAMS ET. AL. STRESS SUMMARY .............................................................................................. 27
WORK FLOWASMENC/NDADAMS ET.AL.SUMMARY .................................................................................................. 27
OPEN AUTOPIPEMODEL.............................................................................................................................................. 28
SELECT A RANGE .......................................................................................................................................................... 28
SEISMIC THERMAL LOAD ............................................................................................................................................... 29
ANALYZE MODEL AND OPEN BURIED PIPE RESULT OPTIONS ................................................................................................ 30
CREATE ADAMS ET.AL.STRESS SUMMARY ........................................................................................................................ 30
GENERATE BATCH REPORT............................................................................................................................................. 31
MISCELLANEOUS INFORMATION ......................................................................................................................... 33
VIEW SOIL PROPERTIES ................................................................................................................................................. 33
LOAD COMBINATION DIALOG ......................................................................................................................................... 34
BURIED PIPE RESULT OPTIONS DIALOG ............................................................................................................................. 34
SOIL OVERBURDEN CATEGORIES ..................................................................................................................................... 35
SEISMIC +THERMAL CATEGORY ...................................................................................................................................... 35
BUILDING SETTLEMENT CATEGORY .................................................................................................................................. 35
SOIL OVERBURDEN STRESSES APPLICATION ON AUTOPIPEPIPING POINTS.............................................................................. 35
BUOYANCY FORCE EXERTED ON BURIED PIPING ................................................................................................................. 37
LIMITATIONS ............................................................................................................................................................... 37
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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.
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Work Flow Assigning Soil Properties
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 forcalculation 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.
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
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Soil Overburden Loads
Work Flow Soil Overburden Loads
Open Existing AutoPIPE Model
Select pipe range for Soil
Properties
Open Soil Dialog (Insert > SoilProperties) 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
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Open AutoPIPE Model
Open Model SOILOVERBURDEN_1 .DAT
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Select a Range
Select the range A04 N to A07. This will be used to apply the soil load.
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Soil Properties Dialog
Open Soil Propertiesdialog through Insert > Soil Properties. Define the Soil IDto APIP_H and
Maximum Spacing to the default 80 inches, and then click the Enter Soil Propertiesbutton.
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Edit Soil Properties Dialog
Note the default Soil Parameters. These values will be used to apply the soil load to the piping
and for generating soil stiffness properties. 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: TransitionExample". Soil stiffness values can be generated by changing the Calculation Methodand
pressing the Generatecommand button. Click on the Generatebutton to fill out the k1, p1, and
k2 values, then click on the Soil Overburden Loadsbutton to open Soil Overburden Loads
dialog.
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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 Identifieris required to be selected so that user can refer to which pipe IDsare used
on the previous dialog Edit Soil Propertiesin 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 loaddepends on the Surface Live Load Typedropdown 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 Kband Deflection coefficient Kxare
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 theBuried Pipe
Result Optionsdialog. The Buried Pipe Result Optionsdialog must also be used to include the
Soil Overburden Loadsin code compliance of the output report.
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Change the Surface Live Load Typeto Airport-180k, and accept the defaults. The value for f
should now be 17432 psi. Click OK in the Edit Soil Propertiesdialog and Soil Propertiesdialog.
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Run Analysis and Open Buried Pipe Result Options dialog
Open theAnalysis Setsdialog (Load > Static Analysis Sets...) and enable Non Linearoption for
analysis set 1. Press OK on theAnalysis Setsdialog. A confirmation message will appear asking
to analyze the model. Press Yes on the Confirmdialog and press OKon theAnalyze Alldialog
that follows.
Open the Buried Pipe Result Optionsdialog (Tools > Model Options > Buried Pipe Result
Options). Note the default values in the Soil Overburden Categoriessection 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 Input Parametersfrom the Edit Soil
Propertiesdialog are used.
Before accepting changes, be sure to check the Display circ. Wall bending & ring buckling in
code complianceso the results of the soil overburdening is displayed in the output.
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Generate Batch Report
Open Batch Reportdialog (Result > Output Report.). Include Code Complianceas a section
to review Circumferential Wall Bending Stress and Ring Buckling Pressure with allowable values
as per the options selected.
Review the results at each point in the batch output report:
The file SOILOVERBURDEN_2.DAT contains the final result of this tutorial section.
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Seismic + Thermal Load Case
Work Flow Seismic Thermal Load Case
Open Existing AutoPIPE Model
Generate seismic wave
propagation equivalent thermal
case(s) using the Generate
Seismic Thermal Load Case (Load
> Seismic Thermal Load
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.
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
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Open AutoPIPE Model
Open Model SOILOVERBURDEN.DAT
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Select a Range
Select a range to apply to the Soil Overburden Loads
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Soil Properties Dialog
Open Soil Properties dialog through Insert > Soil Properties. Define a soil ID and Maximum
Spacing, and then click the Enter Soil Properties button.
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Edit Soil Properties dialog
Ensure that the values of the soil parameters are what is needed, and click on Seismic Wave
Data to open the Seismic Wave Data dialog.
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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.
The Pipe Identifieris required to be selected so that user can see quick check for specific pipes
on the previous dialog Edit Soil Propertiesin front of dT. When calculating the temperature
using the Generate Seismic Thermal Load Case, AutoPIPE automatically use required pipeproperties at each point.
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 . 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
temperatureis checked, both the strains are added for calculating temperature.
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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.
Check Assign seismic wave data above to all Soil Identifiers.
Seismic Thermal Load
To generate a seismic thermal load case, open the Generate Seismic Thermal Load Casedialog
through Load > Seismic Thermal Load. An existing thermal load case can be modified by
selecting the 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 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
temperatureis checked, both the strains are added for calculating temperature.
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Review the results at each point in the batch output report:
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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
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
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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 (preferably at a point
where the pipe enters a building) by going to Insert > Xtra Data > Imposed Support
Displacement.
Analyze Model and Add Building Settlement
Run the analysis including the user case selected for imposed support displacement in the
analysis set. Open the Buried Pipe Result Optionsdialog through Tools > Model Options >
Buried Pipe Result Options.In the Building Settlement Category section, select the preferred
user case and check the box below it.
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Generate Batch Report
Open Batch Reportdialog through Result > Output Report. Include Code Complianceas a
section to review Building Settlement combination.
Review the results at each point in the batch output report:
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ASME NC/NDAdams 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 (Load >
Generate Seismic Thermal
Categories Case)
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
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Open AutoPIPE Model
Open any existing ASME NC or ASME ND model:
Select a Range
Select a range to apply Soil Properties, Soil Overburden Loads and Seismic Data. Create a soil ID
APIP_V using the American Lifeline Alliance calculation method and keep all default values.
Click the Generatebutton to fill out the k1, p1, k2 and yield displacement columns.
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Seismic Thermal LoadGenerate a seismic thermal load case through Load > Seismic Thermal Loadif Seismic +
Thermal combinations are required to be reported in the Stress Summary.
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Analyze Model and Open Buried Pipe Result Options
Run the analysis on the model and open the Buried Pipe Result Optionsdialog through Tools >
Model Options > Buried Pipe Result Options. You will observe the fields which do not apply in
ASME NC/ND are disabled.
Create Adams et. al. Stress Summary
Open the Stress Summarydialog through Tools > Stress Summary.Create a new Stress
Summary by clicking the Newcommand button. Select the appropriate Service Level. Note that
the Service Level will not affect any of the Adams et. al. stress summary values. Select theBuried PipingasAdams et. al.. 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.
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Load Combination Dialog
After ring buckling , seismic + thermal or building settlement case is enabled in the Buried
Pipe Result Optionsdialog, the Code Combinationstab in the Load Combinationsdialog (Tools >
Combinations) will display the ring buckling as a combination.
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
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Soil Overburden Categories
The first dropdown box the calculation method can be selected, which directly affects the
results produced. It also dictates which values in the Soil Overburden Loadsdialog 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 SoilProperties
dialog. Adding circular bending stress to Sustainedwill 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 casecheck box to enable.Seismic + thermal
allowable safety factor is applied to results as a factor of ring buckling allowable.
Building Settlement Category
Building settlement load casedropdown box displays all available user cases that the building
settlement load can be applied. SeeAdd Building Settlementfor details.
Soil Overburden Stresses Application on AutoPIPE Piping PointsSoil 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:
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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
stress
calculations
Comments
A00 None
A01 to A02 N- SOILA Minus face of bend near point will display soil
overburden stresses due to SOILA
A02 N+ to A02
F+
None
A03 SOILB All intermediate soil points following A03 will have
soil overburden stresses based on SOILB
A04 to A05 N- None If there are no faces (minus, plus) for a piping run
point, the second point will not have soil overburden
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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.
A05 N+ to A05
F-
SOILC When there are two faces (minus, plus) on a piping
point, the minus (-) face will calculate soiloverburden 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+ to A07 F- None A05 F+ will not have any soil overburden stresses
A07 F+ to A09 SOILD 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 pipein the Edit Soil Properties
dialog for buried piping. If the buoyancy forces acting on the pipe due to ground water in the
upward direction exceeds 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.
User may apply a net upward force due to buoyancy in AutoPIPE using the command Insert >
Distributed Loads.
Limitations
Currently there is a limitation that only a single face will be displayed for secondary soil points
after a Tee point (in either the header or the branch direction) in Adams et. al. Stress Summary
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report for ASME NC/ND. This may result in displaying the lower stress from both the faces
(minus and plus) of the secondary soil point for Seismic + Thermal stress if the axial force on the
two faces of the secondary soil point differs.
As a workaround, you can insert a run point very close to the Tee point (in the header and
branch direction, depending on direction of the segment). By doing so, the secondary soil
points after the newly inserted run points will display both faces for the secondary soil points.
For example, consider the following scenario displayed below in A01 is a run point, followed by
A02 Tee point. Point A03 follows the tee point in the header direction, whereas B02 follows the
tee point in the branch direction.
You can insert a run point very close (an inch for example) to A02 on the leg A02-A03 to be able
to see both faces of the secondary soil points. Similarly, you can insert a run point very close toA02 on the leg A02 -B02 to be able to see both faces of secondary soil points. Your model will
look similar to the one shown below after insertion of addition points: