CAESAR II Load Case Editor

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FOR THE POWER,

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The COADE Mechanical EngineeringNews Bulletin is published twice a yearfrom the COADE offices in Houston,Texas. The Bulletin is intended to provideinformation about software applicationsand development for MechanicalEngineers serving the power, process andrelated industries. Additionally, the Bulletinserves as the official notificationvehicle for software errors discovered inthose Mechanical Engineering programsoffered by COADE.

©2001 COADE, Inc. All rights reserved.

V O L U M E 3 0 J A N U A R Y 2 0 0 1

What’s New at COADEPVElite Version 4.10 New Features ............... 1CAESAR II Version 4.30 New Features ......... 4

TANK Version 2.20 Released ...................... 11The New Pipe Stress Seminar Format ......... 11

Technology You Can UseSustained Stresses ...................................... 12Using the New CAESAR II Static Load Case

Builder ...................................................... 19

PC Hardware for the Engineering User(Part 30) ................................................... 25

Program SpecificationsCAESAR II Notices ...................................... 26TANK Notices ............................................... 26CodeCalc Notices ........................................ 27

PVElite Notices ............................................ 27

CAESAR IIVersion 4.30New Features

> see story page 4

SustainedStresses

> see story page 12

Using the NewCAESAR II StaticLoad CaseBuilder

> see story page 19

Article Here

PVElite Version 4.10 New Features(by: Scott Mayeux)

PVElite Version 4.10 contains many new exciting additions. A brief list ofthe enhancements is shown in the table below. This article will discuss a fewof these new features and how they may impact vessel designs.

ASME 2000 addenda has been incorporated Provision to use the 1999 year material database TEMA and ASME tubesheet programs updated to perform multiple load cases Separate entry of m and y factors for partition gaskets User bolt loads in the tubesheet programs Simultaneous Corroded and UnCorroded thick expansion joint calculations ASCE 98 wind code added Rigging analysis with graphical results processor added The input ( thicknesses, rings, repads ) can now be updated by the analysis program The 3-D viewer now has a transparency option Ladder information is now collected User time history input for IS-893 RSM

As always there have been changes to ASME VIII Division 1 and the materialdatabase(s). Typically, new materials are added and obsolescent materials arewithdrawn from the Code. In this revision to the program we have of courseupdated the material tables and now offer the option of using the current (2000)addenda, the pre-1999 addenda (lower allowable stresses) or the 1999 stresstables. The option that allows this is found in the Tools->Configuration dialog.

Another major change was made to both the ASME and TEMA tubesheetprograms. ASME Appendix AA was modified substantially for 2000. Thenew changes themselves do not typically generate answers that are significantlydifferent from the previous year addenda. While the alterations were being

I N T H I S I S S U E :

COADE Mechanical Engineering News January 2001

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made, we added new functionality in the way of multiple load cases.If informed to do so, either of the ASME or TEMA tubesheetprograms can run up to 16 load cases for fixed tubesheet exchangers.These load cases involve different combinations of temperature,pressure (internal and external) as well as corrosion allowance. Thegenerated output for these 16 cases is reduced to a mere 2 or 3pages. Previously, this could have generated up to 60 pages. Asample table of results and the dialog used to control the output isshown below:

Fixed Tubesheet Required Thickness per TEMA 8th Edition:

Thickness Reqd ----- P r e s s u r e s Case Pass/Case# Tbsht Extnsn Pt' Ps' PDif Type Fail----------------------------------------------------------------------1c 2.551 0.879 49.71 0.00 0.00 Fvs+Pt-Th+Ca Ok2c 0.850 0.879 0.00 -2.48 0.00 Ps+Fvt-Th+Ca Ok3c 2.610 0.879 49.71 -2.48 0.00 Ps+Pt-Th+Ca Fail4c 0.770 0.879 0.00 0.00 -0.48 Fvs+Fvt+Th+Ca Ok5c 2.550 0.879 49.71 0.00 -0.48 Fvs+Pt+Th+Ca Ok6c 0.850 0.879 0.00 -2.47 -0.48 Ps+Fvt+Th+Ca Ok7c 2.609 0.879 49.71 -2.47 -0.48 Ps+Pt+Th+Ca Fail8c 0.770 0.879 0.00 0.00 0.00 Fvs+Fvt-Th+Ca Ok1uc 1.662 0.879 19.81 0.00 0.00 Fvs+Pt-Th-Ca Ok2uc 1.279 0.879 0.00 13.43 0.00 Ps+Fvt-Th-Ca Ok3uc 1.662 0.879 19.81 13.43 0.00 Ps+Pt-Th-Ca Ok4uc 1.733 0.879 0.00 0.00 -49.37 Fvs+Fvt+Th-Ca Ok5uc 1.733 0.879 19.68 0.00 -49.37 Fvs+Pt+Th-Ca Ok6uc 1.954 0.879 0.00 13.35 -49.37 Ps+Fvt+Th-Ca Ok7uc 1.954 0.879 19.68 13.35 -49.37 Ps+Pt+Th-Ca Ok8uc 0.750 0.879 0.00 0.00 0.00 Fvs+Fvt-Th-Ca Ok----------------------------------------------------------------------Max: 2.610 0.879 in.

Given Tubesheet Thickness: 2.5625 in.

Note:Fvt,Fvs - User-defined Shell-side and Tube-side vacuum pressures or 0.0.

Ps, Pt - Shell-side and Tube-side Design Pressures.Th - With or Without Thermal Expansion.Ca - With or Without Corrosion Allowance.

Tube and Shell Stress Summary: ————— Shell Stresses ————— Tube Stresses Tube Loads PassCase# Ten Allwd Cmp Allwd Ten Allwd Cmp Allwd Ld Allwd Fail——————————————————————————————————————-——————————————————————————————————————-1c 33 15900 0 -4968 10762 13500 0 -5458 1161 1020 Fail2c 0 15900 -290 -4968 1870 13500 0 -5458 202 1020 Ok3c 33 15900 -290 -4968 12633 13500 0 -5458 1363 1020 Fail4c 28 15900 0 -4968 0 13500 -116 -5287 0 1020 Ok5c 45 15900 0 -4968 10765 13500 -116 -5287 1162 1020 Fail6c 28 15900 -289 -4968 1870 13500 -116 -5287 202 1020 Ok7c 45 15900 -289 -4968 12634 13500 -116 -5287 1363 1020 Fail8c 0 15900 0 -4968 0 13500 0 -5458 0 1020 Ok1uc 3389 15900 0 -5038 3467 13500 0 -5458 374 1020 Ok2uc 1507 15900 0 -5038 0 13500 -1975 -5458 213 1020 Ok3uc 4896 15900 0 -5038 3467 13500 -1975 -5458 374 1020 Ok4uc 2771 15900 0 -5038 0 13500 -11927 -5287 0 1020 Fail5uc 4473 15900 0 -5038 3436 13500 -11927 -5287 371 1020 Fail6uc 2771 15900 0 -5038 0 13500 -13885 -5287 211 1020 Fail7uc 4903 15900 0 0 3436 13500 -13885 -5287 371 1020 Fail8uc 0 15900 0 -5038 0 13500 0 -5458 0 1020 Ok——————————————————————————————————————-——————————————————————————————————————- MAX RATIO 0.308 0.058 0.936 2.627 1.337

Additionally, the thick expansion joint program can now alsoaccommodate calculations in both the corroded and uncorrodedconditions in the same run. The ability of the program to providethis functionality will potentially reduce input errors.

Also in the Component Analysis program (CodeCalc), we haveallowed the entry for separate m and Y factors as well and sketchand column information for all components that have optionalentries for partition gasket information. User defined bolt load datais also available in the tubesheet modules.

In the main analysis section of PVElite there have also been manychanges. One time saving change is that after the analysis (in designmode) has changed any data values such as thicknesses, stiffeningrings, basering data or reinforcing pad information, the input can beautomatically updated by the program at the user’s request. Toillustrate this, review the model below. We have requested theprogram to add angle type stiffeners to this vessel.

After the program has generated the new input, it will ask forconfirmation to use the new data.

January 2001 COADE Mechanical Engineering News

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After accepting the changes, here is how the model appears.

Other new items include the option of entering ladder data in theplatform dialog. As shown below, the 3-D graphics have also beenupdated to draw the ladders. Note that the transparency option hasbeen turned on for the shell and cone elements.

Another major addition to this version is that the program can nowperform a rigging analysis. This is the computation of bending andshear stresses in a vessel when it is being lifted from the horizontalposition. The rigging analysis requires that the location of the lugsbe entered in as well as the impact factor for lifting. The impactfactor accounts for how “rough” the vessel is lifted. This valuegenerally lies between 1 and 2, but values as high as 3.0 can be used.If the impact factor is less than 1.0 or the lug distances are notdefined, the program will not perform the analysis. The mainobjective is to determine if the stress levels are excessive duringlifting. The program computes a combined bending plus shearstress check. The result of this check should be less than or equal to1.0. The result of a typical rigging analysis is shown below.

RIGGING ANALYSIS

Total weight of the vessel (No liquid) Twt 92238.39 lb.Impact weight multiplication factor Imp 1.50Design lifting weight, DWT = Imp * Twt 138357.58 lb.Elevation of the tail lug 0.50 ft.Elevation of the lifting lug 70.00 ft.Length of element used for the analysis, INC 1.00 ft.Overall height (node to node) 94.77 ft.Elevation of the vessel center of gravity 44.26 ft.

Design reaction force at the tail lug 51250.46 lb.Design reaction force at the lifting lug 87107.12 lb.

Critical values: Max stress Elevation Allowables psi ft. psi—————————|—————————————————|—————————————————|————————————————————————Bending | -3772.13 | 30.38 | 14518.90 (UG-23)Shear | -470.55 | 69.95 | 11280.00 (0.4*Sy)—————————|—————————————————|—————————————————|————————————————————————

AISC Unity Check was 0.2600 at 29.44 ft. (must be <= 1.0).

—— Note: Plot data successfully generated ... ———


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The graph shown below depicts the combined bending plus shearstress. The graph tool is invoked from the main screen after therigging results data file has been generated. The arrows on thetoolbar switch between the different graphs.

Another update to version 4.10 came in the form of the ASCE 98wind design code. This code is nearly identical to its predecessor,ASCE 95. However, the computation of the gust response factorfor both static and dynamic cases has been slightly altered. Newvalues of the dynamic gust factor have been found to be slightlylower than those computed by the previous edition of ASCE. Thestatic gust factor is slightly higher than previous values.

There are several other enhancements to PVElite that have not beenmentioned here. The updates to the user guide will contain moreinformation. This product is scheduled for an early January 2001release date.

CAESAR II Version 4.30New Features

(by: Tom Van Laan & Richard Ay)

CAESAR II Version 4.30 is a major release providing users withsignificantly enhanced analysis capabilities, as well as additionaluser interface improvements. A list of the major additions andimprovements for Version 4.30 are listed in the table below.

CAESAR II Version 4.30 Features Improved 3-D graphics New Load Case Editor, offering different combination methods, load scale factors, and more Undo/Redo in the input module Z-axis vertical MS WORD as an output device Code Compliance report (statics only) Load Case Report ODBC/XML “wizard” interface for CAESAR II input and output Graphics in the WRC 107 Module Animated Tutorials New Configuration Options User-Configurable Toolbar in Input Module Updated piping codes: B31.1, B31.3, ASME NC, ASME ND

Graphics Improvements:

The 3D graphics have been improved to provide more informationto the user. These improvements include:

When the button is in selected mode, the user can add annotations,with leader lines, to the graphics.

Font type, size and color, may be changed for the annotation

through use of the button, followed by the Fonts tab.

Clicking the or the buttons (or using the Options-Diameters

or Options-Wall Thickness menu commands) highlights the pipingmodel, by color, according to its diameters or wall thicknesses,respectively.

Three new standard views (YX, ZX, and ZY) have been added.

Standard views are accessed by the , , , , , , and (isometric) buttons.

Changes to graphics settings are restored whenever users exit andreturn to the graphics view. Alternatively, the user may set a“standard” setup to be always restored upon entering graphics. This

is done through the use of the button, followed by the User

Options tab.

The CAESAR II Animation module has been converted to usethese new 3D graphics. Zooming, rotating, and panning can now beeasily controlled via the mouse, in exactly the same manner as theinput graphics.

Static Load Case Editor Enhancements:

The CAESAR II Static Load Case editor now offers much moreuser control. New features include use of scale factors whenincluding load components in load cases or previous load cases inload combinations; user-defined load case names; user-controlledcombination methods (for combination cases only); and greateruser control of what output data gets produced.


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Note that previous load cases are now referred to, in combinationcases, as L1, L2, L3, etc. (Load Case 1, Load Case 2, Load Case 3,etc.) rather than DS1, FR2, ST3, etc., since it is no longer meaningfulto talk about combinations being done at the “displacement level”,“force level”, or “stress level”.

Scale factors for load components and previous load cases incombinations: When building basic load cases, load components(such as W, T1, D1, WIND1, etc.) may now be preceded by scalefactors such as 2.0, -, 0.5, etc. Likewise, when building combinationcases, references to previous load cases may also be preceded byscale factors as well. This provides the user with a number ofbenefits:

1) In the event that one loading is a multiple of the other (i.e., SafeShutdown Earthquake being two times Operating Basis Earthquake,only one loading need be entered in the piping input module; it maybe used in a scaled or unscaled form in the Load Case Editor.

2) In the event that a loading may be directionally reversible (i.e.,wind or earthquake), only one loading need be entered in the pipinginput module; it may be used preceded by a + or a – to switchdirectionality.

Load Rating Design Factor (LRDF) methods may be implementedby scaling individual load components by their risk-dependentfactors, for example:

1.05W+1.1T1+1.1D1+1.25WIND1

User-defined load case names: CAESAR II now offers a secondtab on the Static Load Case screen – Load Case Options. Amongother features, this screen allows the user to define alternative, moremeaningful Load Case names, as shown in the figure.

These user-defined names appear in the Static Output Processor inthe Load Case Report (for more information, see below), and mayalso be used in place of the “program” load case names anywhere inthe Static Output Processor, by activating the appropriate optiontherein.

Note, these load case names may not exceed 132 characters inlength.

User-controlled combination methods: For combination cases,CAESAR II now offers the user the ability to explicitly designatethe combination method to be used. Load cases to be combined arenow designated as L1, L2, etc. for Load Case 1, Load Case 2, etc.,with the combination method selected from a drop list on the LoadCase Options tab. The available methods are:

Algebraic: This method combines the displacements, forces,moments, restraint loads, and pressures of the designated loadcases in an algebraic (vectorial) manner. The resultant forces,moments, and pressures are then used (along with the SIFs andelement cross-sectional parameters) to calculate the pipingstresses. Load case results are multiplied by any scale factors(1.8, -, etc.) prior to doing the combination. (Note that theobsolete CAESAR II combination methods DS and FR usedan Algebraic combination method. Therefore, load cases builtin previous versions of CAESAR II using the DS and FRmethods are converted to the Algebraic method. Also, newcombination cases automatically default to this method, unlessspecifically otherwise designated by the user.) Note that in theload case list shown in the figure, most of the combinationcases typically are built with the Algebraic method. Note thatAlgebraic combinations may be built only from basic (i.e.,non-combination) load cases or other load cases built using theAlgebraic combination method.

Scalar: This method combines the displacements, forces,moments, restraint loads, and stresses of the designated loadcases in a Scalar manner (i.e., not as vectors, but retainingconsideration of sign). Load case results are multiplied by anyscale factors prior to doing the combination (for example, for anegative multiplier, stresses would be subtractive). This methodmight typically be used when adding “plus” or “minus” seismicloads to an operating case, or when doing an Occasional Stresscode check (i.e., scalar addition of the Sustained and Occasionalstresses). (Note that the obsolete CAESAR II combinationmethod ST used a Scalar combination method. Therefore,load cases built in previous versions of CAESAR II using theST method are converted to the Scalar method.)

SRSS: This method combines the displacements, forces,moments, restraint loads, and stresses of the designated loadcases in a Square Root of the Sum of the Squares (SRSS)manner. Load case results are multiplied by any scale factorsprior to doing the combination; however, due to the squaring


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used by the combination method, negative values vs. positivevalues will yield no difference in the result. This method istypically used when combining seismic loads acting inorthogonal directions.

Abs: This method combines the displacements, forces,moments, restraint loads, and stresses of the designated loadcases in an Absolute Value manner. Load case results aremultiplied by any scale factors prior to doing the combination;however, due to the absolute values used by the combinationmethod, negative values vs. positive values will yield nodifference in the result. This method may be used when doingan Occasional Stress code check (i.e., absolute summation ofthe Sustained and Occasional stresses). Note that the OccasionalStress cases in the figure are built using this method.

Max: For each result value, this method selects thedisplacement, force, moment, restraint load, and stress havingthe largest absolute value from the designated load cases; so noactual “combination”, per se, takes place. Load case resultsare multiplied by any scale factors prior to doing the selectionof the maxima. The report shows the signed value. Thismethod is typically used when determining the design case(worst loads, stress, etc.) from a number of loads. Note that the“Maximum Restraint Load” case shown in the figure uses aMax combination method.

Min: For each result value, this method selects the displacement,force, moment, restraint load, and stress having the smallestabsolute value from the designated load cases; so no actual“combination”, per se, takes place. Load case results aremultiplied by any scale factors prior to doing the selection ofthe minima.

SignMax: For each result value, this method selects thedisplacement, force, moment, restraint load, and stress havingthe largest actual value, considering the sign, from the designatedload cases; so no actual “combination”, per se, takes place.Load case results are multiplied by any scale factors prior todoing the selection of the maxima. This combination methodwould typically be used in conjunction with the SignMinmethod to find the design range for each value (i.e., maximumpositive and maximum negative restraint loads).

SignMin: For each result value, this method selects thedisplacement, force, moment, restraint load, and stress havingthe smallest actual value, considering the sign, from thedesignated load cases; so no actual “combination”, per se,takes place. Load case results are multiplied by any scalefactors prior to doing the selection of the minima. Thiscombination method would typically be used in conjunctionwith the SignMax method to find the design range for eachvalue (i.e., maximum positive and maximum negative restraintloads).

User control of output availability:

CAESAR II allows the user to specify whether any or all of the loadcase results are retained for review in the Static Output Processor.This is done through the use of two controls found on the Load CaseOptions tab. These are:

Output Status: This item controls the disposition of the entireresults of the load case — the available options are Keep orDiscard. The former would be used when the load case isproducing results that the user may wish to review; the latteroption would be used for artificial cases such as the preliminaryhanger cases, or intermediate construction cases. For example,in the load list shown in the figure, the Wind only load casecould have been optionally designated as Discard, since it wasbuilt only to be used in subsequent combinations, and has noreal value as a standalone load case. Note that load cases usedfor hanger design (i.e., the weight load and hanger travel casesdesignated with the stress type HGR) must be designated asDiscard. Note that for all load cases created under previousversions of CAESAR II, all load cases except the HGR casesare converted as KEEP; likewise the default for all new cases(except for HGR load cases) is also KEEP.

Output Type: This item designates the type of results that areavailable for the load cases which have received a KEEPstatus. This could be used to help minimize clutter on theoutput end, and ensure that only meaningful results are retained.The available options are:

Disp/Force/Stress: This option provides displacements,restraint loads, global and local forces, and stresses.Example: This would be a good choice for Operatingcases, when designing to those codes which do a codecheck on Operating stresses, because the load case wouldbe of interest for interference checking (displacements),restraint loads at one operating extreme (forces), and codecompliance (stresses). Note that basic (non-combination)and DS combination load cases developed under previousversions of CAESAR II are converted with this Disp/Force/Stress type. Likewise, new load cases created alsodefault to this Disp/Force/Stress type.

Disp/Force: This option provides displacements, restraintloads, and global and local forces. Example: This wouldbe a good choice for Operating cases, when designing to acode which does not do a code check on Operating stresses,because the load case would be of interest for interferencechecking (displacements) and restraint loads at one operatingextreme (forces).

Disp/Stress: This option provides displacements andstresses only.


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Force/Stress: This option provides restraint loads, globaland local forces, and stresses. Example: This might be agood choice for a Sustained (cold) case, because the loadcase would be of interest for restraint loads at one operatingextreme (forces), and code compliance (stresses). Notethat FR combination load cases developed under previousversions of CAESAR II are converted with this Force/Stress type.

Disp: This option provides displacements only.

Force: This option provides restraint loads, and global andlocal forces only.

Stress: This option provides stresses only. Example: Thiswould be a good choice for a Sustained plus Occasionalload case (with Abs or scalar combination method), sincethis is basically an artificial construct used for code stresschecking purposes only. Note that ST combination loadcases developed under previous versions of CAESAR IIare converted with this Stress type.

Undo/Redo in the input module:

Any modeling steps done in the CAESAR II piping input modulemay be “undone”, one at a time, using the Undo command, activated

by the button on the toolbar, the Edit-Undo menu option, or theCtrl-Z hot key. Likewise, any “undone” steps may be “redone”

sequentially, using the Redo command, activated by the buttonon the toolbar, the Edit-Redo menu option, or the Ctrl-Y hot key.An unlimited number of steps (limited only by amount of availablememory) may be undone.

Note that making any input change while in the middle of the “undostack” of course clears the stack of redoable steps.

Z-axis vertical:

Traditionally, CAESAR II has always used a coordinate systemwhere the Y-axis coincides with the vertical axis. In one alternativecoordinate system, the Z-axis represents the vertical axis (with theX-axis chosen arbitrarily, and the Y-axis being defined according tothe right-hand rule). CAESAR II now gives the user the ability tomodel using either coordinate system, as well as to switch betweenboth systems on the fly (in most cases).

Defaulting to Z-axis vertical: The user’s preferred Axis Orientationmay be set using the Tools-Configure/Setup option, on theGEOMETRY DIRECTIVES tab. Checking the Z-axis Verticalcheckbox causes CAESAR II to default any new piping, structuralsteel, WRC 107, NEMA SM23, API 610, API 617, or API 661models to use the Z-axis vertical orientation. (Note that old modelswill appear in the orientation in which they were last saved.) Thedefault value in Configure/Setup is unchecked, or Y-axis vertical.

Orienting a piping model to Z-axis vertical: A new piping modelwill determine its axis orientation based on the setting in theConfigure/Setup module, while an existing piping model will usethe same axis orientation under which it was last saved. The axisorientation may be toggled from Y-Axis to Z-Axis Vertical byactivating the checkbox on the Kaux-Special Execution Parametersscreen, as shown in the figure.

Activating this checkbox causes the model to convert immediatelyto match the new axis orientation (i.e., Y-values become Z-values,or vice versa), so there is effectively no change in the model – onlyin its representation, as shown in the following figures:


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This allows any piping input file to be immediately translated fromone coordinate system into the other.

When including other piping files in a piping model, the axisorientation of the included files need not match that of the pipingmodel. Translation occurs immediately upon inclusion.

When including structural files in a piping model, the axis orientationof the included files need not match that of the piping model.Translation occurs immediately upon inclusion.

The axis orientation of the Static Load Case Builder (i.e., wind andwave loads), the Static Output Processor, the Dynamic Input Module,and the Dynamic Output Processor is dictated by the orientation ofthe model’s input file.

Orienting a structural model to Z-axis vertical: A new structuralmodel will determine its axis orientation based on the setting in theConfigure/Setup module, while an existing structural model willuse the same axis orientation under which it was last saved. Theaxis orientation may be toggled from Y-Axis to Z-Axis Vertical bychanging the value of the VERTICAL command, activated by

clicking the button on the toolbar, or through the Commands-

Miscellaneous-VERTICAL menu command, as shown in the figure.

Note: Unlike the piping and equipment files elsewhere inCAESAR II, toggling this setting does not translate the structuralinput file, but rather physically rotates the model into the newcoordinate system, as shown in the figures below:

(Note to Beta testers: Is it OK to handle the axis orientationconversion differently in the Structural Input Module than how it ishandled elsewhere in CAESAR II?)

When including structural files in a piping model, the axis orientationof the included files need not match that of the piping model.Translation occurs immediately upon inclusion.

When analyzing a structural model on its own, the axis orientationof the Static Load Case Builder (i.e., wind and wave loads), theStatic Output Processor, the Dynamic Input Module, and theDynamic Output Processor is dictated by the orientation of thestructural model’s input file.

Orienting an equipment model to Z-axis vertical: The WRC107, NEMA SM23, API 610, API 617, and API 661 equipmentanalytical modules may also utilize the Z-axis vertical orientation.A new equipment model will determine its axis orientation based onthe setting in the Configure/Setup module, while an existingequipment model will use the same axis orientation under which itwas last saved. The axis orientation may be toggled from Y-Axis toZ-Axis Vertical by activating the checkbox typically found on thesecond data input tab of each module, as shown in the followingfigures:


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Activating this checkbox causes the model to convert immediatelyto match the new axis orientation (i.e., Y-values become Z-values,or vice versa), so there is effectively no change in the model – onlyin the terms of its representation.

When using the Get Loads From Output File button to read inpiping loads from CAESAR II output files, the axis orientation ofthe piping files need not match that of the equipment model.Translation occurs immediately during the read-in of the loads.

WORD as an output device:

For those users with access to Microsoft WORD®, CAESAR IIprovides the ability to send output reports directly to WORD. Thispermits the use of all of WORD’s formatting features (font selection,margin control, etc.) and printer support from the CAESAR IIprogram. This feature is activated through use of the button (or

some variant) instead of the (display), (print), or (print tofile) buttons when producing a report.

WORD is available as an output device from the following modules:

Static Output Processor: Multiple reports may be appended to

form a final report by selecting the desired reports, clicking the button, closing Word, selecting the next reports to be added, clicking

the button again, etc. A Table of Contents, reflecting thecumulatively produced reports always appears on the first page ofthe WORD document.

Dynamic Output Processor: This processor operates exactly asdoes the Static Output Processor: Multiple reports may be appendedto form a final report by selecting the desired reports, clicking the

button, closing WORD, selecting the next reports to be added,

clicking the button again, etc. A Table of Contents, reflectingthe cumulatively produced reports always appears on the first pageof the WORD document.

Intersection SIF and Bend SIF Scratchpads, WRC 297, FlangeAnalysis, B31G, and Expansion Joint Rating: Clicking the button performs the calculation and sends the results to WORD.

WRC 107: Clicking the button, rather than the button,performs the initial WRC 107 calculation and sends the results to

WORD. Subsequently, clicking the button performs the SectionVIII, Division 2 summation and appends those results to the WORDdocument.

NEMA SM23, API 610, API 617, API 661, HEI, and API 560:Pressing the button performs the calculation and sends theresults to WORD.

Code Compliance report:

Stress checks for multiple static load cases may be included in asingle report using the Code Compliance report, available from theStatic Output processor. For this report, the user selects all loadcases of interest, and then highlights Code Compliance under ReportOptions. The resultant report shows the stress calculation for allload cases together, on an element-by-element basis.

Load Case Report:

The Load Case Report documents the Basic Names (as built in theLoad Case Builder), User-Defined Names, Combination Methods,Load Cycles, and Load Case Options of the static load cases. Thisreport is available from the General Computed Results column ofthe Static Output Processor.


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ODBC/XML Wizard for CAESAR II input and output:

CAESAR II now offers an ODBC “Wizard” for immediateinterfacing (in addition to the in-line interfacing offered previously)of both input and output piping model data. (Note that the inputdata may only be accessed through the Wizard; while the in-lineinterface still transfers only the output data.)

This Wizard, besides being compatible with ODBC (MicrosoftAccess and Excel) can also export data in XML format. (Note thatthe Excel interface, which was excruciatingly slow under the previousversion of CAESAR II has been changed to produce a semi-colondelimited text file, which can be imported into Excel very quickly.)

The interface is accessed via the Tools-External Interfaces-DataExport Wizard menu command from the CAESAR II Main Menu.This brings up the initial Wizard screen; the exported data set canbe developed by simply responding to the questions and clickingthe Next buttons.

The setup procedure defined in the previous newsletter is stillrequired prior to accessing the new wizard.

Graphics in the WRC 107 Module:

The WRC 107 Analysis module now provides a graphicalrepresentation of the nozzle and its imposed loads. This can be

accessed via the button on the toolbar.

The displayed load case (SUS, EXP, OCC) can be varied byselecting the tab for that load case immediately before activating thegraphics.

Animated Tutorials:

Under the Help-Animated Tutorials menu of the CAESAR II MainMenu, the user can find a list of a number of “Viewlets” which useanimation, text, and voice over to demonstrate answers to commonlyasked questions. (Clicking on the topic runs the tutorial.) Thesetutorials, which typically have durations ranging from 30 seconds to5 minutes, cover a variety of topics.


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TANK Version 2.20 Released(by: Richard Ay)

In September 2000, TANK Version 2.20 was officially released.This version of TANK incorporated Addendum 1 to the 10th Editionof API-650. Changes in this Addendum include materialmodifications and changes to the way corrosion is handled in theSeismic computations of Appendix E. Since the release of Version2.20 in September, two updates have been issued and are availablefor download from the COADE web site. These updates correct adata problem in non-US structural steel databases, modify roofallowable stress checks, and modify live-load reporting for roofdesigns.

Anyone using a version of TANK prior to Version 2.20 shouldupgrade immediately. All users of Version 2.20 should ensure theyhave the build of 001205 installed.

New Pipe Stress Seminar Format(by: Dave Diehl)

Many of you received our new CAESAR II seminar mailer in lateNovember or early December. If you haven’t, you can review itscontent on our web site or contact us to mail or fax one to you.Beyond the 4-color presentation, the most striking component is thelabel “New Format for 2001”. We have expanded the staticanalysis section from three days to five days and the dynamicanalysis section from two days to three days. We have four staticsessions and three dynamics session scheduled through 2001.

Reasons for the change

At the conclusion of each seminar we ask all students to evaluateour course content, instructors and materials. It is the response weread again and again that indicates people want more time using theprogram in group exercises and in individual workshops. Anothercommon comment is the course pace is too rapid, that there is toomuch information to assimilate. We are addressing these issues byextending the duration of the two segments to allow more time todevelop the topics and work with the software. Another commonsuggestion is to provide both an introductory course and an advancedcourse. That approach was tried several years ago when we had athree-day introductory course just ahead of the standard five-daycourse. We were dissatisfied with the result of those arrangements,as many students who did not attend the introductory course stillrequired introductory training to the chagrin of the other students.We have always had to deal with varying levels of student experience.By slowing down the pace of the course and increasing time on thecomputers, we hope to improve the confidence and competence ofall students.

The new static analysis session format

The seminar now has more structure in the day-to-day format. Thefirst day will introduce the subject of pipe flexibility and stressanalysis focusing on the piping code requirements and generatingproper and effective CAESAR II input. Morning will be lectureand afternoon will be spent working with the program. Tuesdaywill have the same morning/afternoon split but now the focus is onproperly designing piping systems. We will still focus on designconsiderations for each of the basic load categories. Program workwill highlight output review and the redesign cycle; that is, identifyingthe significant results and using them to direct system modification.All of Wednesday will be on the computers. We will review anduse many of the added modeling and analysis features of the program.This day will be spent with a job very similar to the tutorial found inthe CAESAR II Applications Guide. Thursday and Friday, theadded static analysis days, will be set aside for group exercises andworkshops. Four different subjects will be covered—transmissionpiping, occasional load evaluation, fiberglass pipe, and jacketedriser design. We understand that these items are not of universalinterest but they are important components of the program andprovide additional insight to the operations of the program, such asburied pipe, jacketed pipe, and fatigue analysis. Friday afternoonwill be set aside for suggested approaches to documenting andreproducing an analysis. The week will end with two or three smallworkshop problems to reinforce the learned skills of piping systemmodeling, evaluation and redesign.

The new dynamic analysis session format

The three dynamics sessions are scheduled on Monday to Wednesdayof the week following the static analysis sessions. There is no carry-over from the previous week so students can attend either the staticsor dynamics segment or both, if they wish. The content from theold, two-day session remains but the pace is reduced and newmaterial is added. Monday morning covers the required theory andthe afternoon is a harmonic analysis exercise. Tuesday developsseismic analysis of piping systems and surveys several approachesto relief valve discharge analysis. This survey was published in theDecember 1998 newsletter and provides an intuitive look at thedifferent types of dynamic analysis. The third day has a groupexercise reviewing time history analysis in CAESAR II and theafternoon gives us an opportunity to practice what was learned –two or three small workshop problems.

Schedule for 2001

One item that has changed in our seminar brochure is the extent ofour seminar schedule. We normally print a two-year calendar butwith this new format we thought it best to treat it with some healthyskepticism and only announce the schedule for 2001. This scheduleappears below:


12

Statics Dynamics

5-9 Feb. 12-14 Feb.

14-18 May 21-23 May

17-21 Sept. 24-26 Sept.

12-16 Nov. Not offered

COADE also provides in-house training at your site and trainingorganized by your local CAESAR II dealer. In both cases, a fulleight-day course may not be practical. For in-house applications,this course can be tailored to focus the content and fit the availableschedule. Dealers will probably maintain the current five-daycourse covering statics and dynamics or break the seminar into twoindependent courses. Contact your dealer to learn more.

Continuing Education Units

You may be interested in knowing that our courses are monitoredby an outside organization for consistency and effectiveness. InMarch 1997 the International Association for Continuing Educationand Training (IACET) certified COADE as an Authorized CEUSponsor. The Continuing Education Unit or CEU is a standardmeasure of contact hours in training; basically ten contact hoursequal one CEU. IACET is quite rigorous in their criteria forauthorizing CEU sponsors. COADE has adjusted the course content,presentation, and documentation to meet their standards. This yearwe have renewed our application as an IACET Authorized Provider.We are currently in the renewal cycle of that certification. Amongother uses, these CEUs serve as credit toward the maintenance of aProfessional Engineering license in those states where suchcontinuing education is required. To learn more about IACET youcan visit www.iacet.org. The five-day course will yield 3.5 CEUsand the three-day course will 2.1 CEUs. If you do the math, that’sseven contact hours a day. In a change from previous courses, wewill start at 9AM rather than 8AM. This will decrease the sessionsfrom four hours to three-and-a-half hours and ease the intensity ofeach session.

Responding to your comments

Once again, it is in response to the evaluations completed by ourstudents that we have introduced these changes. This new format isnot intended to pull old students back for additional training as thenew content is not segmented into a discreet section. But thiscourse will provide more complete coverage of those existing topics,introduce new topics and allocate more time to using the program.Obviously, one of the major concerns we have with this new courseformat is the amount of time we are taking from your regularschedule. Oftentimes the situation is such that when you really need

the training (a hot project is starting) you don’t have the time toattend, and when you have the time to attend (no project; you are onoverhead) you don’t have the funding. We hope that your company’scommitment to quality work and continuing education will allow abroader outlook on the value of this course.

Sustained Stresses(by: John C. Luf of Washington Industrial Process,

Cleveland, OH)

What’s A Sustained Stress and why do we care about it?

Due to what may seem to some people, the controversial nature ofthis articles’ contents I would like to make it perfectly clear THESEARE MY OWN OPINIONS! Although, I am sure some may agreeand yet others will disagree with some of the content of this article.My intent in writing this article is to provide a forum for discussion,give sound advice, and some insight into the subject matter from thepast, present, and possibly the future points of view.

Well where to start? Perhaps we should start with a definition of theword “Sustained”. From my Random House Dictionary...- Sustained“To keep up or keep going as an action or process.”

So how does this apply to the design of piping systems? Stressescaused by thermal displacements of the system are often called“secondary” or “self limiting”. This is because ordinarily thesestresses decrease (slightly) over time. This is illustrated in thefigure below, excerpted from one of Markls’ original papers on thesubject of “Flexibility or Stress Analysis”.


13

You can see that the stress level is not “sustained” it decreases overtime. As for why, a detailed discussion on this subject can be foundin various publications. Suffice it to say because these stresses aredisplacement limited their very nature is self-limited. If the readerwishes to ponder this a bit more, a simple example would be to, takean L bend geometry anchored on each end. Imagine it heated orcooled to the same temperature time and time again. The stresseswill never increase over the maximum from the first heat up so longas the maximum temperature of the first heat up is never exceeded.If the strains in the L bends’ elbow exceed the yield stress of themetal (as is permissible by the B31 codes) the small area of higheststress that exceeds the yield strength of the metal in the elbow“yields” or deforms. This deformation then redistributes the internalstrain energy to a larger surface and hence the peak stress valuedecreases as shown in the hypothetical graph in the figure above.This cycle of load application, material yielding, and strainredistribution will occur repeatedly during the first few cycles.After the strain has been fully redistributed the system will havebeen “shaken out”. This entire phenomenon is often described as astrain controlled phenomena. After full shakeout occurs allsubsequent cycles will behave in an elastic manner.

Well what types of stresses are “sustained”? Or better yet whattypes of imposed loads on a piping system are sustained andunrelenting? For an earth bound or planetary-based piping systemeverything within that planets field of gravity is constantly loadedby the gravitational field in a “sustained” manner. Therefore weightis a sustained load. Based on the science of Strength of Materialswe know that the bending stress for a simply supported “beam” hasthe maximum stress, located along the bottom of the pipe, at themidpoint of the span, in the outermost fiber of the pipe.

Mmax at point (C)

M maxw l

2⋅8

:=

and σMax

Mmax

Z

What other loads are sustained in nature, that act on piping systems?In general piping systems which become candidates for analysis arepressurized. This internal pressure loads the pipe walls in tension.Therefore pressure is generally considered a “sustained” load (σ

L ).

A fair question might be asked, “If these loads do not producestresses which are self limited what would be the consequences ofan overstressed system?” Lets say there is a hypothetical pipingsystem with a span in it that imposes a weight induced bendingstress well above the SMYS (Specified Minimum Yield Strength)of the metal. Let us also assume during construction the fittersworried about the saggy, droopy, pipe and add some chainfalls atthe midspans of the longer spans. After hydrotesting is finished thefitters start cleaning up, they pull the first chainfall out and the nextand so on... The pipe is highly over stressed.... Guess what? Whenthey take off their chainfalls they also get an extra work order! Theextra work is to replace the pipe, which has collapsed, torn out andis lying in a pile of twisted metal on the floor below. This is one ofthe major concerns of sustained loads; they are also known as“collapsing” loads. Other real life examples are buildings, whichsuddenly collapse under their weight loads.

I will digress for a moment to talk about the sustained loads ofpressure and weight. Piping systems that are filled and then drainedas a part of their normal operation have that portion of their weight,which is the fluid, acting as a cyclic load. In like manner these typesof systems would have the internal pressure acting as a cyclic load.These cyclic loads are “fatigue” based loads. Indeed extremepressure cycling (unsteady flow pulsation) has been known to causefailures. However most piping systems do not operate in thesemanners (except incidentally), but if a system does operate in thismanner, the issue of sustained versus fatigue type loads should beconsidered, however for most systems a few cycles of filling anddraining are of no significance.

Now what does B31.3 say about “sustained stresses”? 302.3.5 (c)“The sum of longitudinal stresses in any component in a pipingsystem, due to pressure, weight and other sustained loadings shallnot exceed S

h in (d) below. The thickness of pipe used in calculating

SL

shall be the nominal thickness T minus mechanical, corrosion,and erosion allowance c, for the location under consideration. The


14

loads due to weight should be based on the nominal thickness of allsystem components unless otherwise justified in a more rigorousanalysis.” Axial deadweight loads should be included with bendingin calculating these stresses.

Phew, just think my co-workers and family accuses me of beinglong winded! Well let's take the long paragraph (consisting of only3 long sentences) apart one step at a time.

The first sentence combines bending stress due to weight, andlongitudinal stress due to internal pressure. This combination isbased upon the principle of superposition. The stress in the outermostsurface on the bottom of the pipe, (according to simple beamtheory) at the midspan due to a bending moment is a tensile stress.(Whereas the outermost top of the pipe is under compression.) Thistension stress is combined with the longitudinal stress due to pressure.These summated stresses are compared against the allowable valueof S

h. This is a more profound thing than people realize. First S

h

stands for the “hot stress” or... the “basic allowable stress at themaximum elevated temperature expected during the displacementcycle being analyzed.” For most materials it is 2/3 of the SMYS(specified minimum yield strength) of the material.

This is why when CAESAR II detects internal pressure in the inputfile it recommends the “code load case” of W+P. Because this loadcase in the program (W+P) contains no thermal displacements somepeople refer to this load case as “the cold stress” load case. This iswholly incorrect! The Code requires these “sustained type” stressesto be reviewed not against the S value of the metal at 70°F but ratherat the operating temperature of the metal. The code S value itselfmay seem overly conservative (in most cases it is 2/3 of the SMYSor 1/3 of the tensile strength of the material, whichever is lower attemperature) but don’t forget these loads are “sustained” loads. Ifthe metal yields due to these applied loads it will continue to yielduntil it fails.

The curve above is a typical carbon steel yield curve. As you cansee, once you exceed yield strength the metal continues to stretchunder the applied load for a long time. If the redistribution of theload into the yielded metal does not decrease the stress to belowyield (as the code assumes it does not for sustained loads) the pipingwill fail at the ultimate strength line.

The allowed stress value used is Sh. Why does the code use what

may be a lower allowed S value for metal at a higher temperature?Well the code seems to presume that once the system heats up it willalso be operating with internal pressure inside the system. In orderto assure the structural integrity of the piping to these sustainedloads under these circumstances the S

h is used.

In the remaining code sentences we see some additional interestingthings. The Code uses the approach that it is possible to have themajority of metal in place in a system in a non-corroded state withthe point(s) of highest Sustained stresses being corroded as far asstrength is concerned. This approach may be called conservative bysome, but it cannot be faulted as being unsafe!

Markl3 (for those who don’t know, A.R.C. Markl and his colleagueswere the founding fathers of stress evaluation in the B31 code!)separated the sustained stresses in his original work from the thermaldisplacement and operating allowable stress range. This approachguards against incremental collapse due to ratcheting effects.

Sustained Stress Multipliers (Indices):

Sustained Stress Indices (SSI) (or whatever they end up beingcalled):

Why the long Code paragraph instead of a simple formula for SA as

found under 302.3.5 (1a) i.e., SA=f (1.25S

c+0.25S

h)? My belief is

that some of the reluctance of the committee to provide an equationfor S

L is because of something we have not yet discussed and is not

yet in the Code (ASME B31.3) at the present time.

I hope the readers are all familiar with the term Stress IntensificationFactor (SIF). These SIFs are used to multiply the beam elementbased calculated thermal (or) other type of displacement stresses inorder to approximate the actual level of (higher stresses) that willoccur in the piping component. These SIFs as published in AppendixD of the code are based on physical fatigue tests of actual components.Once the fitting breaks (a through wall leak develops) a simplecalculation is made as follows:

SM

Z

ia

S Nb( )⋅

a 245000psi⋅

N number_cycles_to_failure

b 0.2


15

Factors a, and b are material specific, values shown are for carbonsteel.

This calculation is unique from some standpoints. First in lieu ofpolished bars, actual welded piping components are tested. Second,all SIFs’ are calibrated against a pipe butt weld. The standard pipebutt weld is assigned an SIF of 1.0.

I have just spent a large amount of effort discussing SIFs, why?Well as you can see a fatigue test multiplier (SIF) has very little todo with a “Sustained type load”. Testing for a sustained type loadmight be something on the order of adding weight onto the end of afitting in a test setup and seeing how much weight it takes to causethe fitting to collapse. Then compare that load (perhaps assumingthat it has reached and exceeded the SMYS of the test specimen)versus a calculated beam element stress. A formula might look likeSustained Stress Index (SSI) SSI = SMYS/Calculated Stress (basedupon the actual collapsing load) and shall be no less than 1.0.

If we consider this in a “thought experiment” with some variouscommon piping components we can develop a feel for what an SSImight be. Consider first an elbow. With a Standard Wt 6NPS LRelbow we can see where the effect might not be too large. Howeverconversely a 6x6 NPS standard weight unreinforced intersectionwould probably collapse with a much greater difference between itand a calculated single piece beam element.

Failing all else I suppose we could set up a testing program.However, to my knowledge such a testing program does not exist.

So to recap the current state as far as SSI factors are concerned...

1) SIFs are not applicable to Sustained “collapsing type” loads.

2) SSI factors may vary significantly based on the fitting geometryand may be of greater significance for some fittings thanothers.

3) The ASME B31.3 committee does not have a testing programto derive SSIs currently, although it could be said variousagencies such as the Welding Research Council or the PressureVessel Research Council stand ready to develop these factorsif funding becomes available (corporate donations welcome).

4) The code currently does not address SSIs or have an expressionwritten for the calculation of S

L.

What to do about the SSI?

So what’s a poor design stiff supposed to do? I have found over theyears to truly understand the issues of applying code rules to adesign one must be a historian and must be widely read of variouspiping codes. When you buy a copy of a B31 code book you buythe latest version of that code. Unfortunately the many accumulated

years of history of interpretations do not necessarily shine boldlyand visibly in the latest edition. For instance the B31.3 committeehas rendered two opinions on the subject of a SSI. In oneInterpretation (#1-34 (2/23/81)) they said the designer could ignorethe effect of any SSI and use a factor of 1.0. In another separateinterpretation (# 6-03 (12/14/87)) they said the designer could use afactor of 0.75 x SIF. This seems confusing, but in part it is causedby a lack of information. Maybe if we look elsewhere we can gainsome help?

Turning to ASME B31.1 we find some interesting things on thissubject matter. We find first of all an expression for S

L! Also we

find the calculated SL stresses being multiplied by a factor of

0.75SIF. So if we base our engineering on nothing other thanpopulism it seems like we should use a SSI = 0.75 SIF ≥ 1.0, at leastfor right now1. So for the time being I would recommend that thisfactor of 0.75 SIF ≥ 1.0 = SSI be used in analysis. This can easily beset in the CAESAR II configuration setup.

Set up of the configuration file (file name CAESAR.CFG) is readilyaccomplished through the Main menu as follows…

1. From the main menu window select the configure set up icon.

2. Next select the SIF’s and Stresses tab.


16

3. Select the 0.75 option from the drop down box and don’tforget to exit with save.

If for no other purpose this factor can act as a screening tool. Forinstance I would be less concerned over a slightly over stressed tee/intersection using 0.75 SIF as the SSI than an elbow1. In case ofdoubt, though, a more rigorous review using alternate methodsshould be made… (When in doubt make it stout, or refine yourcalculations).

Non - Linear Pipe Supports (+y’s):

Personal Computers are the constant companions of design engineerstoday. The advent of this ubiquitous technology is both a blessingand a curse. Currently in our world of compressed schedules andsegmented work efforts, pipe supports, their locations and types,are often selected by a designer on the basis of span charts. TheStress Analyst / Piping Engineer then accounts for thermaldisplacements (as well as their impact) after the fact.

This approach while it may be more efficient (a maybe at best) cancause significant difficulties to occur as far as sustained stresses inthe piping system are concerned. What am I talking about? Whendisplaced by thermal effects the system may completely or partially“lift off” certain non-linear pipe supports.

What types of supports are non-linear? Pipe racks, trapezes, clevishangers, or any other support which supports the pipe fully only inone direction. These types of supports are unable to provide thesame supporting force at the displaced position versus the non-displaced position. I should also point out a “legitimate” use of a +ysupport that is lifted off is a maintenance or turn around support.These supports allow maintenance of flanged connections byproviding support for one or more sides of a flange which is un-bolted during maintenance shut downs.

Pump

Hot Oil @ 600 FCarbon Steel A53 Gr BPipeCarbon Steel Fittngs,Valves, and Pump

Load OnSupport Beam

Time

Temperature

Side Elevation of HypotheticalPump Support

2'-9"

Max Ld

No LdMaxOpTemp

AmbTemp

12'

-0"

In the example above the load on the support beam carrying the pipeand some of the valve weight quickly decreases as the system comesup in temperature until finally it is lifted off and drops to zero loadbefore the system gets to its maximum temperature! (Guess whathappens to the pump loading? I suppose that’s what spring cans areused for!)

The result of this type of support lift off is that if one evaluates thesystem for S

L stresses in only one state you may not be seeing the

complete picture. The code requires evaluations for SL at various

temperatures. Some people call these evaluations as “cold” sustainedand “hot” sustained stress checks.

The following example illustrates the problems associate with supportlift off. I have been permitted to borrow it from its current authorMr. Don Edwards of ASME B31.3 task group B. The task grouphas been working on a non mandatory “Appendix S” whose purposewill be to illustrate the code and its relationship to computerizedanalysis. Note… in no way, shape, or form is this supposed torepresent good practice! It is only a hypothetical layout!

10'-0"

40'-0"

10'-0"

20

'-0"

Typ

.

Stated Data:Material-Carbon Steel A106Grb, AstmA234 Gr WPBNPS-16Wall-Standard Wt (0.375" Nom Wall)Elbows LRInsulation-3" Thk Density = 11.0 #/Ft3Corrosion Allowance = 1/16"Fluid Density=1.0 S.G.Maximum Op. Pressure = 500 P.S.I.G.Maximum Op. Temperature = 600 FMinimum Operating Temp = 70FInstallation Temp = 70 F

Fix Y

+Y

Anchor6 D.O.F.

Proposed Appendix S Model

1020

45 55

8040'-0"

Typ.

10'-0"

Typ.

90

Y

X

Z

+Y


17

When the loop heats up, it will lift off the upper supports. The firstpass S

L code stress calculation is made with the upper supports

“active” i.e., supporting the pipe. This is required to obtain thethermal displacements from the installed position to the displacedposition. When S

L is evaluated with the pipe sitting on these

supports SL stresses are within the code allowable.

However when we look at the CAESAR II Restraint Summation(in the 132 column format) at nodes 45 and 55 we see the loads goto zero in the operating case and a look over at the displacementsshows a +y movement.

The liftoffs’ effects should be re-evaluated by performing anotherS

L analysis with the supports at nodes 45 and 55 removed from the

model. When this is done it turns out the code SL stress limit is

exceeded (this evaluation is made using a SSI = 0.75 SIF ≥ 1.0).This second analysis determines the sustained stress (B31.3 Codestress) redistribution, it is not used for any other purpose (i.e. codestress review of displacement stresses). Leave the thermal data inthe job so that the proper S

h is used. To sum up, the supports at

nodes 45 and 55 are used for evaluating the thermal displacements,but are removed to evaluate the code sustained stress level. (Itshould be noted that restraint summaries shown herein show thepure thermal forces to illustrate the book keeping on the restraints.These thermal loads would not be used for support design).

When this sample problem was discussed at the committee's lastmeeting a visitor asked, “Well what should be done?” Some of thecommittee members stated that first, an evaluation with the liftedoff supports removed from the model should be made and thenfinally some members said… “That redesign of the system shouldbe made to eliminate the over stressed condition.” Clearly some ofthe committee members’ opinions do not agree with ignoring liftoff. The visitor then mentioned, “You should put a spring can(s) onthe top of the loop!” I myself countered that spring cans might notbe necessary! I disagreed strongly and suggested that jigglingsupport locations around would probably solve the overload. Indeedmoving the supports at 20 and 80 inwards a couple of feet (towardsthe loop) make the overstressed condition go away (Although themidpoint sag would probably be unacceptable by most criteria’s fordrainage). Sometimes spring cans are good things (especiallyadjacent to rotating and other sensitive/delicate equipment), and

other times adding a fixed pipe support(+y) or moving supportsaround will easily solve a S

L overstress. In any event it is unlikely

that if or when Appendix S is published that the sample problemswill show a preferred solution. This is because the committee's roleis to tell the users to do their homework, give advice on how to dothe homework, but the committee will never do the users' homeworkfor them.

Judicious use of Engineering Judgement:

It is the authors’ opinion that “engineering judgement” can andshould play a role in the process of sustained stress evaluations.Turning to another example:

5'-0" 5'-0" 5'-0"

3'-0"8'-0"

3'-0"

5'-0" 5'-0"

10 20 30

40 50

60

70 80

90

Design Data:Code: ASME B31.3Pipe: A53Gr B SmlssWall : Standard Wt.NPS: 6Elbows: L.R. 90Degree B.E.

Process Data:Maximum operating temperature :180FMinimum operating temperature: 70 FInstallation temperature : 70 FMaximum operating pressure 250PSIG

Y

X

Z

We have another “hypothetical” layout; this contrived geometry isfor illustration only. Other than the close support spacing in thisexample I have seen lines run in racks supported in similar fashionon either side of the riser elbow pair.

If we look at a deflected plot of the operating case we see that thepipe has clearly lifted off and when we take a look at the restraintsummation we see this as well.


18

Load shift to 0, sticks out!

Small + movement

Looking closely we see the liftoff(s) in the operating case are byextremely small amounts. So what would be the appropriate way todeal with this design?

Well the first step has already been taken. That is a review of therestraint summation. This essential step I suspect is often ignored!I have heard people occasionally say that CAESAR II does notevaluate support lift off correctly. However, I feel that a pipingengineer reviewing, and supervising the non-sentient computer isessential to the work process. The review process and the ability ofwho does the review is very important. “When the lift offdisplacement is equal to or less than the fabrication tolerance of thepiping, the designers gray matter is much more important than thecomputers chip speed” (D. Edwards).

One method of evaluation could be by feel, which is, it is readilyapparent that the bending stress portion of S

L is minuscule. Therefore

the liftoff adjacent to the elbow becomes of no concern. However Isuppose there are those persons who are trying to develop feel. Inthat case I suggest another way that you could look at this would beto use a span chart such as found in MSS SP 69 2. Looking at itsspan limits for 6NPS Std. Wt. Steel pipe that is used in water servicewe see that we could have spans seventeen feet (17’) in length. Thedistance from node 40 to node 80 is only eleven feet (11’) wellwithin the span chart limit. What about the effect of the SSI on theelbows calculated code stresses? Well it feels like it should be low,but in order to evaluate it numerically we will have to remove thesupport lifted off at node 70, copy the file into a new name, andreanalyze it using the SSI = 0.75 SIF ≥ 1.0 CAESAR IIConfiguration option. When we do this and examine a stress reportwe see all is well….

It should be noted that if one were to calculate the SIF for theseelbows per the Code you would get the number shown in the report.CAESAR II will use a numerically adjusted value per theconfiguration setup as a multiplier despite the fact that the code SIFis shown on the report. Why not adjust the value shown on thereport? Well the column heading says SIF, not SSI therefore inessence because the codes have not adopted the use of a SSI whatdo you call the ad hoc SSI in code terminology?

At this point I would suggest that we have met the intent of ASMEB31.3. We have evaluated the S

L stresses in two states and have

complied with the code stress limit in both cases. I would suggestnotations be placed on the restraint summation report at the liftedoff nodes, such as “Support liftoff is incidental, spans as lifted offcomply with ASME B31.3 S

L limits”

So a summation of one man’s opinions:

Adult supervision of the computer is always required. WhatI mean by this statement is, that I consider the computer to belike a young child who requires adult or parental supervisionat all times.

Use the CAESAR II, 0.75SIF option in the configurationsetup as a multiplier for the S

L case. Its probably not “100%

right” but it is more appropriate than 1.0. Besides which,usually a maximum deflection criterion dominates the pipesupport layout and design. (Editor's Note: CAESAR IIdefaults to use of the full SIF, not 1.0 as the SSI.)

Review the 132 column restraint summary reports looking forload shifts or lift off at non-linear +Y supports. Pay closeattention to supports adjacent to rotating equipment.


19

Evaluate the amount, type and locations of lift offs. If lift offversus the system's design is minor or incidental write yourcomments on the archival report.

If the lift offs are more than minor, such that their effects onthe code S

L cannot be readily discerned, remove the supports

(+y’s) that are lifted off from the model. Rerun the sustainedstress case.

If redesign is required, modify the support scheme by supportrelocation, or adding +y supports, or spring cans – with thethought in mind that spring cans (except when adjacent tosensitive equipment nozzles) are usually less desirable.

References (additional reading):

1) “Pressure Vessel and Piping Codes” Journal of PressureVessel Technology August 1988 “Commentary on Class 2/3Piping Rules” Authors comment… this provides some of thetechnical background behind the use of the factor of 0.75 as aSIF multiplier.

2) Manufacturers Standardization Society of the Valve andFitting Industry, Inc. Standard Practice SP69 "Pipe Hangersand Supports – Selection and Application".

3) Transactions of the ASME, February 1955, “Piping FlexibilityAnalysis”

A huge thanks to my editors…

Rich Ay, COADEDave Diehl, COADEDon Edwards, Phillips PetroleumPhil Ellenberger, WFI

Late Breaking News

Over a year ago COADE started the process to register its nameand all product names as trademarks with the U.S. Patent andTrademark Office. We are pleased to report that bothCAESAR II and PVElite are now registered to COADE. Othernames should be registered soon.

Vessel seminar dates are announced. Our three day vesselseminar using CodeCalc and PVElite is scheduled for 21-23February and 10-12 October 2001. The first two days covercomponent analysis (found in CodeCalc and PVElite) and theoptional third day continues with a whole vessel approach todesign in PVElite. Ask for a brochure or view a copy on our website for more information.

Please register as a user of our software. Registered users receivea brief e-mail identifying new program releases and Builds asthey become available. This “heads up” will keep you up to datewith the current software and eliminate your need to monitor ourweb site for new postings.

Utilizing the New Load Case Editorin CAESAR II Version 4.30

(by: Richard Ay)

For Version 4.30, the Load Case Editor in CAESAR II experiencedsignificant revisions. These modifications simplify the specificationof load cases, streamline the output data, and allow additionalanalysis capabilities. The revised load case editor dialog is shownin the figure below. In this figure, areas that have been changed areindicated with numerals, and are explained in the followingparagraphs.

Item 1: In previous versions of the software, the available “stresstypes” were listed on the lower left side of the dialog. (The “stresstype” determines what stress equations are used in the solutionmodule.) Users could either drag the “stress type” onto a load case,or manually type in the abbreviation. As of Version 4.30, the“stress type” for each load case is selected from a “drop list”.Simply clicking on the “stress type” grid cell activates this “droplist”.

Item 2: In previous versions of the software, algebraic load casecombinations could be combined at various levels; displacement,force, or stress. This was indicated on the right side of the dialog,where DS indicated the displacement level, FR indicated the forcelevel, and ST indicated the stress level. As of Version 4.30, this“combination level” idea is obsolete, and has been replaced by an“output type indicator”. The type of output desired for a particularload case can be specified on the “Load Case Options” tab, whosedialog is shown in the figure below.

Item 3: The “Load Case Options” tab is new for Version 4.30.Clicking on this tab presents additional load case controls. Thesenew controls are shown in the figure below.


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Item 4: Any load case component can be preceded by a numericmultiplier. This means that safety factors can be applied at the loadcase level, instead of in the input.

Load Case Name: This grid column can be used to define a namefor a particular load case. For example, instead of wondering what“W+T1+P1+D1+F1” might represent, you can now type in a namesuch as “Operating + Cold Spring”. Both the formal load casecomponent definition and the load case name can be used at theoutput level for review and report generation.

Output Status: This grid column is used to specify whether or nota particular load case will have output available for review. The“Discard” setting allows intermediate and construction load casesto be ignored by the output processor, which simplifies outputreview and evaluation.

Output Type: For load cases where the “Output Status” is set to“Keep”, this grid column specifies exactly what type of output willbe available. So for a typical operating case, this setting shouldindicate “Displacement/Force”, while a typical expansion case shouldindicate only “Stress”. With these settings, stresses would beunavailable for the operating case, while displacements, forces, andrestraint loads would be unavailable for the expansion case.

Combination Method: Previous versions of CAESAR II used an“algebraic” combination method when combining load cases ateither the displacement or force level, and an “absolute” or “scalar”combination method when combining load cases at the stress level.

{The use of an “algebraic” combination is required by the B31codes (for instance see ASME B31.3 Paragraph 319.2.3) for reviewof displacement stresses. In the review of B31 piping systems theuser is strongly encouraged to continue the use of the algebraicsummation method for the review of displacement stresses.}

As discussed above, this “level” idea is now obsolete, beingsuperceded by the “output status” and “output type” settings.However, there are instances where it is necessary to control thecombination method used, as well as other methods in addition to“algebraic” and “scalar”. The additional combination methods of“absolute”, “SRSS” (square root sum of squares), “Min”, “Max”,“Signed Min”, and “Signed Max”, have been added for Version4.30.

Complete documentation on the correct usage of these options canbe found in the CAESAR II documentation, as well as the on-linehelp. However, an example will be used to illustrate the usage ofthese new capabilities.

Assume we must statically analyze a model (with only linearboundary conditions) for a seismic event. (A plot of this symmetric,simple model is shown below.) For this seismic event, “G loads”have been specified for each global direction, X, Y, and Z. Theseloads have been defined as U1, U2, and U3 respectively, as shownin the figure below.

To properly address the code requirements for occasional stresschecks, and to evaluate the restraint loads on the system, the followingset of load cases have been defined.

Case Components Stress Type Comments 1 W+P1+T1 OPE Operating 2 W+P1 SUS Sustained 3 U1 OCC Seismic load X 4 U2 OCC Seismic load Y 5 U3 OCC Seismic load Z 6 L1-L2 EXP Expansion range code case 7 L3+L4+L5 OCC Resultant seismic load, SRSS combination 8 L1+L7 OCC Operating plus seismic combined absolutely,

hot restraint loads 9 L2+L7 OCC Sustained plus seismic combined absolutely,

cold restraint loads, code case 10 L9, L8 OCC Maximum restraint loads

With the new load case editor, these load cases can be definedexactly as laid out in the table above. This load case layout isdefined on two related dialogs, as shown in the figures below.


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The figure above is the familiar load case editor screen. Notehowever that the load case stress type is now selected from a “droplist” for each specific load case. This drop list is shown activatedfor the last load case in the figure above. The above screen isessentially the same as in previous versions of CAESAR II. Thetwo obvious differences are the “stress type drop list” and the setupof the combination load cases. Consider for example load case 6above. Previous versions of CAESAR II would have listed case 6as DS1 - DS2. As of Version 4.30, this same load case is listed asL1 - L2. The combination methods and the output type (formerlycombination level) are defined on the second load case definitiondialog, shown in the figure below.

The second dialog shows the advanced load case controls offeredby Version 4.30. First, note that the load cases can be givenmeaningful names - these names are user defined. Second, the“Output Status” column provides two settings for each load case;“keep” and “discard”. In this context, “keep” means that the datafrom the load case will be available for review in the output processor,while “discard” means that the data from the load case will not beavailable for review. The “discard” setting would typically beapplied to “construction load cases”, those cases used solely tobuild other cases.

The “Output Type” column indicates what type of data will beavailable for review in the output processor (assuming the “OutputStatus” is set to “keep”). Setting a load case to “Disp/Force/Stress”means that displacements, forces (and restraint loads), and stresseswill be available at the output level for review. Setting a load caseto “Disp/Force” means that only displacements and forces (andrestraint loads) will be available at the output level for review. Thisis the preferred setting for typical B31.1/B31.3 operating cases(OPE), where the stress results are not code related and are ofminimal use. Conversely, setting a load case to “Stress” means thatonly stresses will be available at the output level for review. This isthe preferred setting for typical B31.1/B31.3 expansion cases, whereonly the stress range is needed. The displacements and forces forthis case are also ranges and are typically of minimal use.

The final column on this dialog “Comb Method” defines for eachcombination load case, the combination method to be employed. Inversions of CAESAR II prior to 4.30, combination load casescombined at the displacement or force level were combinedalgebraically. Load cases combined at the stress level were combinedin a scalar fashion. As of Version 4.30, the user has control over thecombination methods. Additionally, the combination methods havebeen expanded to also include Absolute, SRSS, Min, Max, signedMin, and signed Max.

The best way to understand the new capabilities of the static loadcase editor is through the use of the example started above.Examining the load cases in more detail shows:

Load cases 3, 4, and 5 are comprised of only a single seismicload (direction). By themselves, these load cases provideminimal information, they exist solely as construction cases.

Load case 6 is the standard expansion load case, whichdetermines the extreme displacement stress range bysubtracting case 2 from case 1. In previous versions ofCAESAR II, this load case would have been denoted as DS1- DS2.

Load case 7 is a combination case, constructed by computingthe square root sum of squares of load cases 3, 4, and 5. (Priorversions of CAESAR II could not perform this computation.)This load case yields the combined effect of the three seismicloads.


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Load case 8 is a combination case, constructed by adding theoperating case to the combined seismic case. This combinationis made taking the absolute values from each of the componentload cases. (Prior versions of CAESAR II could not performthis computation.) This load case yields the absolute value of“hot” restraint loads.

Load case 9 is a combination case, constructed by adding thesustained case to the combined seismic case. This combinationis made taking the absolute values from each of the componentload cases. (Prior versions of CAESAR II could not performthis computation.) This load case yields the “cold” restraintloads. This case is also the code compliance case satisfyingthe requirements the “sustained plus occasional” code equation.

Prior versions of CAESAR II performed this code computationat the stress level, i.e., ST2 + ST7.

Load cases 10 is a combination case, constructed by taking themaximum results from cases 8 and 9. The absolute magnitudeof the values from each case are used in determining themaxima. (Prior versions of CAESAR II could not performthis computation.) This load case yields the “maximum”restraint loads.

For this particular job, a review of the restraint summary for loadcases 3, 4, 5, and 7 shows expected results for this symmetricmodel, as illustrated in the figure below.

Similarly, a restraint summary comprised of load cases 1, 2, and 7yields expected results in cases 8 and 9, as illustrated in the figurebelow.

And finally, a restraint summary comprised of case 8, 9, and 10shows the maximum restraint loads as expected, illustrated in thefigure below.

In a production environment, with a real job, we can take moreadvantage of these new load case capabilities. In this simpleexample, the results of load cases 3, 4, 5, and 7 are of minimal


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interest - these are just construction load cases. Additionally, wedon’t care what the stresses in the Operating case are, nor do wecare what the displacements and forces are in the Expansion case.We can make these eliminations on the “Load Case Options” tab ofthe static Load Case Editor. The figure below shows this dialogafter these changes have been made.

Upon running the analysis with this load case setup, the resultingoutput menu is modified, as shown in the figure below.

Here we see that the load cases set to “discard” in the Load CaseEditor are labeled “Not Active” at the output level. We cannotreview data for these load cases. This greatly simplifies reporting,and the need to explain why stresses for these cases are of noimportance. Another option that makes interpreting the resultseasier is the “user specified load case names”. These user definednames can be shown in the output by selecting the “Load CaseNames” option from the “Options” menu, or by clicking on the load

case name icon in the tool bar. Activating this option modifies

the output menu as shown in the figure below.

Output review now consists of reviewing displacements for cases 1and 2 (operating and sustained), restraint loads for cases 1, 2, 8, 9,and 10 (operating, sustained, hot+seismic, cold+seismic, andmaximum), and stresses for cases 2, 6, and 9 (sustained, expansion,and occasional). In reviewing these latter stress cases, we can takeadvantage of the new “Code Compliance” report. This report isshown in the figure below.


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To aid in keeping track of how the load cases were setup andcombined, the new “Load Case Report” is available. This reportdetails the load case components, the user defined name, the outputstatus, and the combination method. A sample load case report isshown in the figure below.

The example above details the basic approach that can be applied tooccasional loads. The above load cases are sufficient for mostrequirements. However, an even more detailed study of the system’sbehavior can be evaluated by refining the load cases. For example,consider the load case setup as defined in the following two figures.

Note that in the first of these figures, load case #4 applies a scalefactor of 0.667 to the “U2” vector. A scale factor can be applied toany load case component if desired. In the second figure, we seethat the seismic loads are combined in load case #7 by the SRSSmethod. It is the resultant of this case which is then combined (plusor minus) with the operating and sustained cases to obtain theminimum and maximum restraint loads for the hot and coldconditions. These four conditions are defined as load cases 8through 11.

Load case #12 acquires the “signed maximum” from load cases 8through 11. Similarly, load case #13 acquires the “signed minimum”from load cases 8 through 11. The difference between these twoload cases, provides the extreme restraint load range which occursduring the seismic event.

A similar scale factor scheme can be applied to a “cold spring”situation. If the “cold spring” is modeled using the “temperaturemethod” (say in the T2 vector), then the 2/3 scale factor can beapplied at the load case level, obviating the need for a duplicate job.

This static Load Case Editor provides much greater capabilitiesthan in previous versions of the software. By understanding thepurpose of the load cases, a great deal of additional systemevaluations can be defined and automatically performed by thesoftware. Future versions of CAESAR II will see even moreenhancements dealing with the setup and manipulation of loadcases and their components.


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PC Hardware for the EngineeringUser (Part 30)

(by: Richard Ay)

By the time you read this, current COADE products will nolonger be supporting the old green External Software Locks(ESLs). All of these older ESLs should have been exchangedby now, for the newer model devices.

Viewlets:

COADE has started to utilize a new educational tool. This toolenables the creation and subsequent playback of small, animatedtutorials, called Viewlets. These Viewlets can be played back ineither Netscape or Internet Explorer.

These Viewlets consist mostly of annotated screen captures, ofeither the computer “desktop” or an application program. Theannotations explain the context of the Viewlet, augmented by cursormovements and optional “voice-over”. A sample screen from arunning Viewlet is shown in the figure below.

The best feature of a Viewlet is that it allows us to show in a matterof minutes, what would ordinarily take a half an hour to explain onthe telephone. The Viewlet allows the author to show exactly whereto move the mouse, and what to click.

To date, COADE has a rather small library of Viewlets. TheseViewlets are available from the COADE web site (shown in thefigure below) by clicking on the link “Animated Tutorials” in theleft hand navigation bar. Successful playback of Viewlets from theweb requires a fast connection to the Internet. Load times for a 28.8dial-up connection are on the order of 1.5 minutes, with an occasionallag in the audio. ISDN or better connections typically don’t sufferthese problems.

These Viewlets will also be shipped with future versions of COADEproducts, as an additional tutorial / support medium.

The “SendTo” Menu:

When using Windows Explorer, right clicking on a file brings up acontext menu. One of the items in this menu is the “SendTo”option. This “SendTo” option will expand to reveal all of thelocations (or programs) that you can send the current file to. Commonitems in this list include floppy drive A, My Briefcase, and e-mail.How do you add or remove items from this list?

Under Windows 95/98/ME, use Windows Explorer and navigate toC:\Windows\SendTo. This folder contains the list of “SendTo”menu options. To remove an item, simply select it and hit the[Delete] key. To add an item, right click in the folder and select“new\shortcut”. When the “shortcut” dialog appears, use the[Browse] button to locate the program to start (a good example isNotepad), the folder to copy/move the file to, or type in the desiredcommand line. Once the command line has been specified, click[Next]. On this final dialog, type in a name for this new shortcut.This name will be what appears on the “SendTo” menu. Afterspecifying the desired name, click [Finish]. The “SendTo” menunow contains the new item.


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Under Windows NT/2000, the procedure is almost identical to theabove description. The only difference is that the “SendTo” optionsare in C:\WinNT\profiles\user_name\SendTo. Here “user_name”is the name used to login to Windows.

Note that if the name you select with the [Browse] button is a foldername, the default action is to move the selected file to that folder. Ifyou want to copy the selected file to the destination folder, holddown the [Crtl] key when selecting the destination folder.

CAESAR II Notices

Listed below are those errors & omissions in the CAESAR IIprogram that have been identified since the last newsletter. Thesecorrections are available for download from our WEB site. Unlessotherwise stated, all of these changes and corrections are containedin the 000801 build of Version 4.20.

1) Analysis Setup Module: Corrected the wave plot for“horizontal acceleration versus phase at zero depth”.

Corrected the determination of the wave/current direction for“-x” cosines. Corrected in the 4.30 release.

Corrected the deletion of spectrum names from the dynamicinput file. Corrected in the 4.30 release.

Corrected the initialization of data for wind when combiningstructures and piping jobs. Corrected in the 4.30 release.

2) Input Module: Corrected the display of “tooltip help” textfor the units display of the expansion joint effective id field.Corrected in the 4.30 release.

Corrected the behavior of the “grid control” to prevent theerroneous display of the previous data on a “cursor focus”change.

Corrected a memory allocation error which caused wind datato overwrite offset data.

Corrected a problem in the 3D Hoops graphics where restraintsapplied to bend mid-side nodes did not plot on the bendelement.

For the NC/ND piping codes the SIF and B2 values wereswitched on the intersection SIF scratchpad display. This wasa display only problem, corrected in the 4.30 release.

Corrected an SIF computation error for TD/12 full encirclementtees.

3) Error Checker: Corrected the tracking of Sc values whenmixing user defined and database allowable stresses.

Corrected printer handling when printing error/warningmessages.


4) Naval DLL: Corrected the hydrodynamic coefficientinterpolation setup for very small Reynolds numbers.

5) Miscellaneous Module: Corrected the flange ANSI pressurerating ratio.


6) Intergraph Interface: Corrected the weight combination ofvalves and flanges when following a bend element.

Corrected the tracking of element properties when programgenerated pipe elements are created for tees and elbows.

7) Material Database: Corrected allowable stress values forseveral materials. Corrected in the 4.30 release.

8) Static Solution Module: Corrected the memory allocationfor the variables used to display the current values of thefriction tolerances. Corrected in the 4.30 release.

9) Element Generator: Corrected the determination of thewave/current direction for “-x” cosines. Corrected in the 4.30release.

10) Structural Input Module: Corrected the operation of the“section id” dialog when “user shapes” are specified - theheight/width dimensions were switched. Corrected in the4.30 release.

Corrected the initialization of data for wind, temperatures 4-9, and pressures 4-9 when combining structures and pipingjobs. Corrected in the 4.30 release.

11) Material Database Editor: Corrected a problem where thevalue of “eff” was modified by a units conversion constant.Corrected in the 4.30 release.

TANK Notices

Listed below are those errors & omissions in the TANK programthat have been identified since the last newsletter. These correctionsare available for download from our WEB site.

1) Input Module: Corrected a network ESL logout problem.Corrected for the 2.20 release.

Added units conversion for the “threads per inch” value in thebolting specification. Corrected for the 2.20 release.

2) Error Check Module: Added units conversion for the“threads per inch” value in the bolting specification. Correctedfor the 2.20 release.


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Reactivated the check for excessive structural allowable stressvalues. Corrected in Build 001024.

3) Solution Module: Modified the seismic calculations toinclude corrosion allowance in the determination of the “wl”term in Section E.4.2. Corrected for the 2.20 release.

Corrected the computation of the “hydrotest allowable stress”to remove the consideration fro the “yield strength reductionfactor” due to temperatures over 200 deg F. Corrected inBuild 001024.

4) Structural Libraries: Modified all non-US libraries tocorrect the cross sectional area and unit weight of pipe shapes.Corrected in Build 001024.

CodeCalc Notices

Listed below are those errors & omissions in the CodeCalc programthat have been identified since the last newsletter. These correctionsare available for download from our WEB site.

1) General:

In the flange, floating head and the tubesheet modules (ASMEand TEMA) the partition gasket factors M & Y, sketch andcolumn can now be specified through a separate input. Inprevious versions, main gasket’s factors where also used forthe partition gasket.

External pressure charts HA-7, CD-1, NFN-21, NFN-22,NFN-23, NFN-24, CS-6, HT-2, HA-6 have been added.

2) Shell module:

A check box for skipping UG-16b, the minimum thicknessrequirement, has been added.

3) ASME Tubesheet module:

Analysis of the configuration “C” fixed tubesheets has beenallowed, after a correction was made for the “gammab”parameter. This was an oversight in the ASME code.

The allowables used for Shell and channel stresses due to jointinteraction, after the Elastic-Plastic iteration, have beencorrected to be 3 * S.

For computing the tube buckling, in case of a fixed tubesheet,the program now asks for the tube end condition k, and spanL for the maximum value of k*L.

4) TEMA Tubesheet module:

For computing the tube buckling, in case of a fixed tubesheet,the program now asks for the tube end condition k, and spanL for the maximum value of k*L.

5) Leg and Lug module:

For continuous ring type support lug, shell section is nowtaken into account along with the ring as the section to resistthe loading.

6) WRC 297 module:

ASME Section VIII Div. 1 material database is replaced bythe Div 2 database.

7) WRC 107 module:

ASME Section VIII Div. 1 material database is replaced bythe Div 2 database.

Interactive control feature, which is used when the WRC 107curve parameters exceed their respective curves, has beenimplemented.

PVElite Notices

Listed below are those errors & omissions in the PVElite programthat have been identified since the last newsletter. These correctionsare available for download from our WEB site.

1) The CodeCalc errors listed above.

2) The internal computation of the saddle extension based on thegiven angle was off by a factor of 2. The computed length wastoo long.

3) For BS Nozzle calculations, the required thickness of conicalsections were computed as if they were cylindrical.

4) The weight computation for horizontal vessel rings placedover the saddles was incorrect. This value was on theconservative side.

5) For BS Nozzle calculations. the corrosion allowance shouldhave been added to the minimum thickness from the table forcomparison.

6) The weight of the saddle was used in computing the weightload on the saddle.


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12777 Jones Rd. Suite 480 Tel: 281-890-4566 Web: www.coade.comHouston, Texas 77070 Fax: 281-890-3301 E-Mail: [email protected]

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