PIPELINE STRESS ANALYSIS WITH CAESAR II

by

Andrey Puruhita

PIPELINE STRESS ANALYSIS WITH CAESAR II

What the different with piping stress ?Pipeline burried modelingAnchor block restrainLoad case combination & result

The difference of piping & pipeline stress analysisPiping modelingCode requirement shall use ASME B31.3

AbovegroundMany support or restrain needed

Pipeline modelingCode requirement use ASME B31.4 for liquid & B31.8 for gas transmissionUsually UndergroundShall use anchor block as a restrain from aboveground-underground conversely

Burried PipeBuried pipe deforms laterally in areas immediately adjacent to changes in directionsIn areas far removed from bends and tees the deformation is primarily axial

PIPELINE BURRIED MODELINGThe Buried Pipe Modeler is started by selecting an existing job, and then choosing menu option Input-Underground from the CAESAR II Main MenuEnter the soil data using Buried Pipe - Soil ModelsDescribe the sections of the piping system that are buried, and define any required fine mesh areas using the buried element data spreadsheetConvert the original model into the buried model by the activation of option Buried Pipe - Convert Input

Input soil models

The buried element description spreadsheet serves several functionsIt allows the user to define which part of the piping system is buried.It allows the user to define mesh spacing at specific element ends.It allows the input of user defined soil stiffnesses

Burried pipe example

Anchor Block RestrainPipeline with a long distance needs block valve, there were a change direction from underground to abovegroundIn this situation pipeline must be installed with anchor block before and after aboveground pipe

Why we need anchor block ?To prevent stress failed on block valve due to axial deformation of a long pipeline

Example of block valve modelingAnchor blockAnchor block

Load Case CombinationTo check stress analysis on pipeline shall use several load case combination as folow :

Sustain Load ( W + P)Thermal Load (T)Combination Load ( W + T + P)

Caesar Stress ResultCAESAR II STRESS REPORT FILE:FOR TUTORIAL CASE 3 (OPE) W+T2+P1 DATE:OCT 1,2009 --Stress(lb./sq.in.)--- --(lb./sq.in.)-- ELEMENT BENDING TORSION SIF'S ALLOWABLE NODES STRESS STRESS IN/OUT PLANE STRESS STRESS %

HIGHEST STRESSES: (lb./sq.in.) OPE STRESS %: 21.06 @NODE 90 STRESS: 12636.4 ALLOWABLE: 60000.0 BENDING STRESS: 3254.8 @NODE 90 TORSIONAL STRESS: 0.0 @NODE 49 AXIAL STRESS: 9455.2 @NODE 130 3D MAX INTENSITY: 30120.4 @NODE 20

60 1357. 0. 1.000 / 1.000 10739. 60000. 18. 70 919. 0. 1.000 / 1.000 10300. 60000. 17.

80 1461. 0. 1.000 / 1.000 10842. 60000. 18. 90 3255. 0. 1.000 / 1.000 12636. 60000. 21.

90 3255. 0. 1.000 / 1.000 12636. 60000. 21. 95 2703. 0. 1.000 / 1.000 12085. 60000. 20.

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