CAESAR_Building Static Load Cases

CAESAR II - User’s Guide Building Static Load Cases

Error Checking, Static Load Cases, and Analysis 6-7

Building Static Load CasesThe first step in the analysis of an error-checked piping model is the specifica-tion of the static load cases. This is done by selection of the Analysis-Static options from the CAESAR II Main Menu (the piping input file must have successfully gone through error checking before this option can be chosen).

A discussion of CAESAR II load cases is included at the end of this chapter. Please refer to it for a description of how the load cases are built.

Upon entering the static load case editor, a screen appears which lists all of the available loads that are defined in the input, the available stress types, and the current load cases offered for analysis. If the job is entering static analysis for the first time, CAESAR II presents a list of recommended load cases. If the job has been run previously, the loads shown are those saved during the last session. A typical load case editor screen is shown below:

Load Case Editor

The user can define up to ninety-nine load cases. Load cases may be edited by clicking on a line in the Load List area.

Only the load components listed in the upper left-hand portion of the screen may be speci-fied in the load cases. The entries must be identical to what is shown on the screen. Avail-

Analysis - Statics

Building Static Load Cases CAESAR II - User’s Guide

6-8 Error Checking, Static Load Cases, and Analysis

able stress types are specified at the end of the load case entry in parentheses. Stress type determines the stress calculation method and the allowable stress to use (if any).

Load Cases may be built through drag and drop actions. Dragging a load component from the Loads Defined in Input list to a line on the load list automatically adds the load com-ponent to the load case, if it is not already included. Highlighted basic load cases may be dragged down to be added to algebraic combination cases (CAESAR II may prompt for combination type). Use the Load Case Options tab to select combination methods and other specifics pertaining to the load cases.

Note Defining a fatigue (FAT) stress type for a load case automatically displays a field in which the number of anticipated load cycles for that load case can be entered.

All basic (non-combination) load sets must all be specified before any algebraic combina-tions may be declared. This rule holds true for user defined and edited load cases.

The following commands are available on this screen:

• Edit-Insert—This command inserts a blank load case preceding the currently selected line in the load list. If no line is selected, the load case is added at the end of the list. Load cases are selected by clicking on the number to the left of the load case.

• Edit-Delete—This command deletes the currently selected load case.

• File Analysis—This command accepts the load cases and runs the job.

• Recommend—This command allows the user to replace the cur-rent load cases with the CAESAR II recommended load cases.

• Load Cycles—This button alternatively hides or displays the Load Cycles field in the Load Case list. Entries in these fields are only valid / required for load cases defined with the fatigue stress type.

Edit - Insert

Edit - Delete

File - Analysis

Recommend

Load Cycles

CAESAR II - User’s Guide Providing Wind Data


Providing Wind DataUp to four different wind load cases may be specified for any one job.

The only wind load information that is specified in the piping input is the shape factor. It is this shape factor input that causes load cases WIN1, WIN2, WIN3, and WIN4 to be listed as an available load to be analyzed. More wind data is required, however, before an analy-sis can be made. When wind loads are used in the model, CAESAR II makes available the screen to define the extra wind load data. Once defined, this input is stored and may be changed on subsequent entries into the static analysis processor.

To specify the wind data needed for the analysis select the tab entitled Wind Load for the appropriate wind load case. The screen shown below appears:

Wind Load Specifications

There are three different methods that can be used to generate wind loads on piping sys-tems:

• ASCE #7 Standard Edition, 1995

• User entry of a pressure vs. elevation table

• User entry of a velocity vs. elevation table

The appropriate method is selected by placing a value of 1.0 in one of the first three boxes.

Providing Wind Data CAESAR II - User’s Guide


When defining a pressure or velocity vs. elevation table the user needs to specify only the method and the wind direction on the preceding screen. Upon pressing the User Wind Pro-file button, the user is prompted for the corresponding pressure or velocity table. If a uni-form pressure or velocity is to act over the entire piping system, then only a single entry needs to be made in the table, otherwise the user should enter the pressure or velocity pro-file for the applicable wind loading.

Note To use the ASCE #7 wind loads, all of the fields should be filled in.

For example, as per ASCE #7, the following are typical basic wind-speed values:

California and West Coast Areas- 124.6 ft./sec. ( 85 m.p.h.)

Rocky Mountains - 132.0 ft./sec ( 90 m.p.h.)

Great Plains- 132.0 ft./sec ( 90 m.p.h.)

Non-Coastal Eastern United States- 132.0 ft./sec ( 90 m.p.h.)

Gulf Coast- 190.6 ft./sec (130 m.p.h.)

Florida-Carolinas- 190.6 ft./sec (130 m.p.h.)

Miami- 212.6 ft./sec (145 m.p.h.)

New England Coastal Areas- 176.0 ft./sec (120 m.p.h.)

CAESAR II - User’s Guide Specifying Hydrodynamic Parameters


Specifying Hydrodynamic ParametersUp to four different hydrodynamic load cases may be specified for any one job.

Several hydrodynamic coefficients are defined on the element spreadsheet. The inclusion of hydrodynamic coefficients causes the loads WAV1, WAV2, WAV3, and WAV4 to be available in the load case editor.

A CAESAR II hydrodynamic loading dialog is shown in the following figure.

In the load case editor, four different wave load profiles may be specified. Current data and wave data may be specified and included together or either of them may be omitted so as not to be considered in the analysis. CAESAR II supports three current models and six wave models. See the CAESAR II Technical Reference Manual for a detailed discussion of hydrodynamic analysis.

Execution of Static Analysis CAESAR II - User’s Guide


Execution of Static AnalysisThe static analysis performed by CAESAR II follows the regular finite element solution routine. Element stiffnesses are combined to form a global system stiffness matrix. Each basic load case defines a set of loads for the ends of all the elements. These elemental load sets are combined into system load vectors. Using the relationship of force equals stiff-ness times displacement (F=KX), the unknown system deflections and rotations can be calculated. The knowns, however, may change during the analysis as hanger sizing, non-linear supports, and friction all affect both the stiffness matrix and load vectors. The root solution from this equation, the system-wide deflections and rotations, is used with the element stiffnesses to determine the global (X,Y,Z) forces and moments at the end of each element. These forces and moments are translated into a local coordinate system for the element from which the code-defined stresses are calculated. Forces and moments on anchors, restraints, and fixed displacement points are summed to balance all global forces and moments entering the node. Algebraic combinations of the basic load cases pick up this process where appropriate - at the displacement, force & moment, or stress level.

Once the setup for the solution is complete the calculation of the displacements and rota-tions is repeated for each of the basic load cases. During this step, the Incore Solution sta-tus screen appears.

CAESAR II - User’s Guide Execution of Static Analysis


Incore Solution Module

This screen serves as a monitor of the static analysis. The screen is broken down into sev-eral areas. The area on the upper left reflects the size of the job by listing the number of equations to be solved and the bandwidth of the matrix which holds these equations. Mul-tiplying the number of equations by the bandwidth gives a relative indication of the job size. This area also lists the current load case being analyzed and the total number of basic load cases to be solved. The iteration count, as well as the current case number, shows how much “work” has already been completed. Load cases with nonlinear restraints may require several solutions (iterations) before the changing assumptions about the restraint configuration (e.g. resting or lifting off, active or inactive) are confirmed. In the lower left screen of the big box are two bar graphs which indicate where the program is in an indi-vidual solution. These bar graphs illustrate the speed of the solution. By checking the data in this first box, an experienced user will have a good idea of how much longer to wait for the results.

Execution of Static Analysis CAESAR II - User’s Guide


The right side of the solution screen also provide information to the user regarding status of nonlinear restraints and hangers in the job. For example, messages noting the number of restraints that have yet to converge or any hangers that appear to be taking no load, are dis-played here. Nonlinear restraint status may be stepped through on an individual basis by using the [F2]/[F4] function keys.

Following the analysis of the system deflections and rotations, these results are post-pro-cessed in order to calculate the local forces, moments, and stresses for the basic load cases and all results for the algebraic combinations (e.g. DS1-DS2). These total system results are stored in a file with the suffix “_P” (e.g. TUTOR._P).

Note The “_A” or input file, the “_P” or output file, and the "OTL" (Output Time Link File) are all that is required to archive the static analysis. The remaining scratch files may be eliminated from the system without any impact on the work com-pleted.

During this post processing, the Status screen lists the current element for which the forces and stresses are being calculated. Once the last element’s stresses are computed, the output processor screen is presented. It is through this menu the graphic and tabular results of the analysis can be interactively reviewed by the user. Interactive processing of output results is discussed in detail in Chapter 7 of this document.

CAESAR II - User’s Guide Execution of Static Analysis


Static Output Screen

Notes on CAESAR II Load Cases CAESAR II - User’s Guide


Notes on CAESAR II Load Cases

Definition of a Load Case

In CAESAR II terms, a load case is a group of piping system loads that are analyzed together, i.e., that are assumed to be occurring at the same time. An example of a load case is an operating analysis composed of the thermal, deadweight, and pressure loads together. Another is an as-installed analysis of deadweight loads alone. A load case may also be composed of the combinations of the results of other load cases; for example, the differ-ence in displacements between the operating and installed cases. No matter what the con-tents of the load case, it always produces a set of reports in the output which list restraint loads, displacements and rotations, internal forces, moments, and stresses. Because of pip-ing code definitions of calculation methods and/or allowable stresses, the load cases are also tagged with a stress category. For example, the combination mentioned above might be tagged as an EXPansion stress case.

The piping system loads which compose the basic (non-combination) load sets relate to various input items found on the piping input screen. The table below lists the individual load set designations, their names and the input items which make them available for anal-ysis.

Designation Name Input items which activate this load case

W Deadweight Pipe Weight, Insulation Weight, Fluid Weight,Rigid Weight

WNC Weight No fluid Contents Pipe Weight, Insulation Weight, Rigid Weight

WW Water Weight Pipe Weight, Insulation Weight, Water-filledWeight, Rigid Weight (usually used forHydro Test)

T1 Thermal Set 1 Temperature #1



.

.

.


P1 Pressure Set 1 Pressure #1



.

.

.


HP Hydrostatic Test Pressure Hydro Pressure

D1 Displacements Set 1 Displacements (1st Vector)

D2 Displacements Set 2 Displacements (2nd Vector)

CAESAR II - User’s Guide Notes on CAESAR II Load Cases


D3 Displacements Set 3 Displacements (3rd Vector)

.

.

.

D9 Displacement Set 9 Displacements (9th Vector)

F1 Force Set 1 Forces/Moments (1st Vector)

F2 Force Set 2 Forces/Moments (2nd Vector)

F3 Force Set 3 Forces/Moments (3rd Vector)

.

.

.

F9 Force Set 9 Forces/Moments (9th Vector)

WIN1 Wind Load 1 Wind Shape Factor




WAV1 Wave Load 1 Wave Load On




U1 Uniform Loads Uniform Loads (1st Vector)

U2 Uniform Loads Uniform Loads (2nd Vector)

U3 Uniform Loads Uniform Loads (3rd Vector)

CS Cold Spring Material # 18 or 19

H Hanger Initial Loads Hanger Design or Pre-specified Hangers

Note Available piping system loads are displayed on the left hand side of the Static Load Case screen.

Basic load cases may consist of a single load such as WNC for an as-installed weight anal-ysis, or they may include several loads added together such as W+T1+P1+D1+F1 for an operating analysis. The stress categories: SUStained, EXPansion, OCCasional, OPErat-ing, and FATigue are specified at the end of the load case definition. The complete defini-tion of the two examples are: WNC (SUS) and W+T1+P1+D1+H (OPE). Each basic load case is entered in this manner in a list for analysis.

When building basic load cases, load components (such as W, T1, D1, WIND1, etc.) may now be preceded by scale factors such as 2.0, -0.5, etc. Likewise, when building combina-tion cases, references to previous load cases may also be preceded by scale factors as well. This provides the user with a number of benefits:

• In the event that one loading is a multiple of the other (i.e., safe Shutdown Earthquake being two times Operating Basis Earthquake, only one load-ing need be entered in the piping input module; it may be used in a scaled or unscaled form in the Load Case Editor.



• In the event that a loading may be directionally reversible (i.e., wind or earthquake) only one loading need be entered in the piping input module; it may be used preceded by a + or a - to switch direction.

• Load Rating Design Factor (LRDF) methods may be implemented by scaling individual load components by their risk-dependent factors, for example:

1.05W + 1.1T1+1.1D1+1.25 WIND1

Note Available stress types may be selected from the pull-down list on each line.

Results of the basic load cases may be combined using algebraic combination cases. These algebraic combinations are always entered following the last of the basic load cases. Com-binations of basic load cases are designated using the prefix L1, L2, etc.

Note All load cases with stress type FATigue must have their expected number of Load Cycles specified.

An example set of loads appears below.

The following family of load cases provides a valid example of algebraic combinations.



Load Case Designation Comments

1 W+T1+P1+H+0.67CS (OPE) Hot operating; note the 0.67 scale factorwhich takes credit only for 2/3 of the cold spring

2 W1+P1+H+0.67CS(OPE) Cold operating: with cold springincluded

3 W1+P1+H(SUS) Traditional sustained case

4 WIN1(OCC) Wind case; note this will be manipu-lated later to represent average wind(1X), maximum wind (2X), as wellas positive and negative directions.

5 L1-L2(EXP) Traditional expansion case, cold tohot (note reference to "L" for"Load", rather than "DS".

6 L1-L2(FAT) Same case but now evaluated forfatigue at 10,000 cycles.

7 L1+L4(OPE) Hot operating with average wind (inpositive direction).

8 L1-L4(OPE) Hot operating with average wind (innegative direction).

9 L1+2L4(OPE) Hot operating with maximum wind(in positive direction).

10 L1-2L4(OPE) Hot operating with maximum wind(in negative direction).

11 L2+L4(OPE) Cold operating with average wind(in positive direction).

12 L2-L4(OPE) Cold operating with average wind(in negative direction).

13 L2+2L4(OPE) Cold operating with maximum wind(in positive direction).

14 L2-2L4(OPE) Cold operating with maximum wind(in negative direction).

15 L3+L4(OCC) Occasional stress case, sustainedplus average wind.

16 L3+2L4(OCC) Occasional stress case, sustainedplus maximum wind.

17 L9+L10+L11+L12(OPE) Maximum restraint load case (thecombination option should beMAX).



Note CAESAR II permits the specification of up to ninety-nine load cases for analysis. In the rare situation where more cases are required, the model should be copied to a new file in order to specify the additional load cases.



Load Case Options Tab

CAESAR II offers a second tab on the Static Load Case screen - Load Case Options. Among other features, this screen allows the user to define alternative and more meaning-ful Load Case names, as shown in the figure below.

User Defined Names

The user-defined names appear in the Static Output Processor in the Load Case Report (for more information, see below), and may also be used in place of the built load case names anywhere in the Static Output Processor, by activating the appropriate option.

Note Load case names may not exceed 132 characters in length.



User Control of Produced Results Data

CAESAR II allows the user to specify whether any or all of the load case results are retained for review in the Static Output Processor. This is done through the use of two con-trols found on the Load Case Options tab. These are:

Output Status

This item controls the disposition of the entire results of the load case -- the available op tions are Keep or Discard. The former would be used when the load case is producing results that the user may wish to review; the latter option would be used for artificial cases such as the preliminary hanger cases, or intermediate construction cases. For example, in the load list shown in the figure, the Wind only load case could have been optionally des-ignated as Discard, since it was built only to be used in subsequent combinations, and has no great value as a standalone load case. Note that load cases used for hanger design (i.e., the weight load case and hanger travel cases designated with the stress type HGR) must be designated as Discard. Note that for all load cases created under previous versions of CAESAR II, all load cases except the HGR cases are 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 are available for the load cases which have received a Keep status. This could be used to help minimize clutter on the output 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. This would be a good choice for Operating cases, when designing to those codes which do a code check on operating stresses, because the load case would be of interest for interference checking (displacements) and restraint loads at one operating extreme (forces).

Disp/Stress

This option provides displacements and stresses only.

Force Stress

This option provides displacements, restraint loads, global and local forces, and stresses. This might be a good choice for the Sustained (cold) case, because the load case would be of interest for restraint loads at one operating extreme (forces), and code compliance (stresses). Note that FR combination loads cases developed under previous versions of versions of CAESAR II are converted with this Force/Stress type.

Disp

This option provides displacements only.

Force

This option provides displacements, restraint loads, global and local forces only.



Stress

This option provides stresses only. This would be a good choice for a sustained plus Occasional load case (with Abs combination method), since this is basically an artifi-cial construct used for code stress checking purposes only. Note that ST combination load cases developed under previous versions of CAESAR II are converted with this Stress type.

Snubbers Active?

Activating this option causes the snubbers to be considered to be rigid restraints for this particular load case. By default, OCC load cases activate this option, while other types of load cases default to an inactive state.

Hanger Design

The three options available here are As Designed, Rigid, and Ignore, and cause CAESAR II to (1) consider the actual spring hanger stiffnesses, (2) model the spring hangers as rigid restraints, or (3) remove the spring hanger stiffnesses from the model, respectively. As Designed should be used for most "real" (non-hanger design) load cases. Rigid should be used for the Restrained Weight case and any Hydrotest Case (if the spring hangers are pinned during it). (Note that during the Restrained Weight Case user-defined hangers will not be made rigid.) Ignore is normally used for the Operating for Hanger Travel Cases -- except in those cases where the user wishes to include the stiffness of the selected spring in the Operating for Hanger Travel Case (and iterate to a solution). In that case, the user should select As Designed for those cases as well. In that case, it is very important that the hanger load in the cold case (in the physical system) be adjusted to match the reported hanger Cold Load.

Friction Multiplier

This multiplier may be used to alter (or deactivate) the friction factors used in this particu-lar load case. The friction factor (Mu) used at each restraint will be this multiplier times the Mu factor at each restraint. Setting this value to zero deactivates friction for this load case.



User-Controlled Combination Methods

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

Algebraic

This method combines the displacements, forces, moments, restraint loads, and pressures of the designated load cases in an algebraic (vectorial) manner. The resultant forces, moments, and pressures are then used (along with the SIFs and element cross-sectional parameters) to calculate the piping stresses. Load case results are multiplied by any scale factors (1.8, -, etc.) prior to doing the combination.

The obsolete CAESAR II combination methods DS and FR used an Algebraic combina-tion method. Therefore, load cases built in previous versions of CAESAR II using the DS and FR methods are converted to the Algebraic method. Also, new combination cases automatically default to this method, unless designated by the user). In the load case list shown in the figure, most of the combination cases are typically built with the Algebraic method.

Note that in the load case list shown in the figure, most of the combination cases typically are built with the Algebraic method. Note that Algebraic combinations may be built only from basic (i.e., non-combination) load cases or other load cases built using the Algebraic combination method.

Scalar

This method combines the displacements, forces, moments, restraint loads, and stresses of the designated load cases in a Scalar manner (i.e., not as vectors, but retaining consider-ation of sign). Load case results are multiplied by any scale factors prior to doing the com-bination (for example, for a negative multiplier, stresses would be subtractive). This method might typically be used when adding plus or minus seismic loads to an operating case, or when doing an Occasional Stress Code check (i.e. scalar addition of the Sustained and Occasional stresses).

The obsolete CAESAR II combination methods ST used a Scalar combination method. Therefore, load cases built in previous versions of CAESAR II using the ST method are converted to the Scalar method.

SRSS

This method combines the displacements, forces, moments, restraint loads, and stresses of the designated load cases in a Square Root of the Sum of the Squares (SRSS) manner. Load case results are multiplied by any scale factors prior to doing the combination how-ever, due to the squaring used by the combination method, negative values vs. positive values will yield no difference in the result. This method is typically used when combining seismic loads acting in orthogonal directions.



ABS

This method combines the displacements, forces, moments, restraint loads, and stresses of the designated load cases in an Absolute Value manner. Load case results are multiplied by any scale factors prior to doing the combination however, due to the absolute values used by the combination method, negative values vs. positive values will yield no difference in the result. This method may be used when doing an Ocassional Stress code check (i.e., absolute summation of the Sustained and Occasional stresses).

Note The Ocassional Stress cases in the figure are built using this method.

Max

For each result value, this combination method selects the displacement, force, moment, restraint load, and stress having the largest absolute value from the designated load cases; so no actual combination per se, takes place. Load case results are multiplied by any scale factors prior to doing the selection of the maxima. This method is typically used when determining the design case (worst loads, stress, etc.) from a number of loads.

Note The maximum Restraint Load case shown in the figure uses a Max combination method.

Min

For each result value, this combination method selects the displacement, force, moment, restraint load, and stress having the smallest absolute value from the designated load cases; so no actual combination per se, takes place. Load case results are multiplied by any scale factors prior to doing the selection of the minima.

SignMax

For each result value, this combination method selects the displacements, force, moments, restraint load, and stress having the largest actual value, considering the sign, from the designated load cases; so no actual combination per se, takes place. Load case results are multiplied by any scale factors prior to doing the selection of the maxima. This combina-tion method would typically be used in conjunction with the SignMin method to find the design range for each value (i.e., the maximum positive and maximum negative restraint loads).

SignMin

For each result value, this combination method selects the displacements, force, moments, restraint load, and stress having the smallest actual value, considering the sign, from the designated load cases; so no actual combination per se, takes place. Load case results are multiplied by any scale factors prior to doing the selection of the minima. This combina-tion method would typically be used in conjunction with the SignMax method to find the design range for each value (i.e., the maximum positive and maximum negative restraint loads).



Recommended Load Cases

When the user first enters the static load case editor CAESAR II recommends, based on the loads defined in the model, three types of load cases: Operating, Sustained, and Expan-sion (but not occasional).

Operating load cases represent the loads acting on the pipe during hot operation, including both primary (weight pressure, and force) loadings and secondary (displacement and ther-mal) loadings. Operating cases are used to find hot displacements for interference check-ing, and hot restraint and equipment loads. Generally when recommending operating load cases, CAESAR II combines weight, pressure case #1, and hanger loads with each of the thermal load cases (displacement set #1 with thermal set #1, displacement set #2 with ther-mal set #2, etc....), and then with any cold spring loads.

Sustained load cases represent the primary force-driven loadings acting on the pipe, i.e., weight and pressure alone. This usually coincides with the cold (as-installed) load case. Sustained load cases are used to satisfy the code sustained stress requirements, as well as to calculate as-installed restraint and equipment loads. Sustained load cases are generally built by combining weight with each of the pressure and force sets, and then with any hanger loads.

Expansion load cases represent the range between the displacement extremes (usually between the operating and sustained cases). Expansion load cases are used to meet expan-sion stress requirements.

Most users will specify only one temperature and one pressure. Such input would simplify the recommended cases to something like:

Case # 1 W+D1+T1+P1+H (OPE) ....OPERATING

Case # 2 W+P1+H (SUS)....SUSTAINED LOAD CASE

Case # 3 L1-L2 (EXP)....EXPANSION LOAD CASE

The user should review any load recommendations made by CAESAR II.

Note CAESAR II does not recommend any occasional load cases. Definition of these are the responsibility of the user.

If these recommended load cases do not satisfy the analysis requirements, they may always be deleted or modified. Conversely, the load cases may always be reset to the pro-gram’s recommended set at any time.

Recommended Load Cases for Hanger Selection

If spring hangers are to be designed by the program, two additional load cases must first be analyzed in order to obtain the data required to select a variable support. The two basic requirements for sizing hangers are the deadweight carried by the hanger (hot load) and the range of vertical travel to be accommodated. The first load case (traditionally called “Restrained Weight”) consists of only deadweight (W). For this analysis CAESAR II includes a rigid restraint in the vertical direction at every location where a hanger is to be sized. The load on the restraint from this analysis is the deadweight that must be carried by the support in the hot condition. For the second load case, the hanger is replaced with an



upward force equal to the calculated hot load, and an operating load case is run. This load case (traditionally called “Free Thermal”) includes the deadweight and thermal effects, the first pressure set (if defined), and any displacements, (W+D1+T1+P1). The vertical dis-placements of the hanger locations, along with the previously calculated deadweights are then passed on to the hanger selection routine. Once the hangers are sized, the added forces are removed and replaced with the selected supports along with their pre-loads (cold loads), designated by load component H. (Note that load component H may appear in the load cases for hanger design if the user has predefined any springs- in this case it would represent the pre-defined operating loads.) CAESAR II then continues with the load case recommendations as defined above. A typical set of recommended load cases for a single operating load case spring hanger design appears as follows:

Case # 1 W ....WEIGHT FOR HANGER LOADS

Case # 2 W+D1+T1+P1 ....OPERATING FOR HANGER TRAVEL

Case # 3 W+D1+T1+P1+H (OPE) ...OPERATING (HGRS. INCLUDED

Case # 4 W+P1+H (SUS) ....SUSTAINED LOAD CASE

Case # 5 L3-L4 (EXP) ....EXPANSION LOAD CASE

These hanger sizing load cases (#1 & #2) generally supply no information to the output reports other than the data found in the hanger tables. Note how cases 3, 4, & 5 match the recommended load cases for a standard analysis with one thermal and one pressure defined. Also notice how the displacement combination numbers in case 5 have changed to reflect the new order. If multiple temperatures and pressures existed in the input, they too would appear in this set after the second spring hanger design load case.

Two other hanger design criteria also affect the recommended load cases. If the “actual cold loads” for selected springs are to be calculated, one additional load case (WNC+H) would appear before case #3 above. If the piping system’s hanger design criteria is set so that the proposed springs must accommodate more than one operating condition, other load cases must additionally appear before the case #3 above. An extra hanger design operating load case must be performed for each additional operating load case used to design springs. Refer to the discussion of the hanger design algorithm for more informa-tion on these options.

CAESAR_Building Static Load Cases

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