The Static/Dynamic Combinations tab is available when Earthquake (spectrum), Relief Loads (spectrum), Water Hammer/Slug Flow (spectrum), and Time History are selected for Analysis Type in the Dynamic Analysis window.
Each analysis can have multiple load case combinations. Multiple static and dynamic cases can exist:
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Each static or dynamic case must be on a separate line.
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The order of the load cases is not important and has no effect on the results.
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Comment lines may be included.
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Static cases alone can be combined without dynamic cases.
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Dynamic cases alone can be combined without static cases.
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Most piping codes combine occasional dynamic stresses with sustained static stresses. This combination is compared to the occasional allowable stress.
Each combination references static load case and dynamic load case numbers to be combined. Any number of static or dynamic loads can be combined in a single combination load case. Each combination is on a separate row.
Additional Options
The following options are also available:
Editing Load Case
Select a load case to edit.
Stress Types
Select the stress type for the load case:
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OPE - Stress from operating loads.
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OCC - Stress from occasional short-term loads.
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SUS - Stress from primary sustained loads.
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EXP - Stress from secondary thermal expansion loads.
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FAT - Stress from fatigue loads.
This option is not available for time history analysis.
Fatigue Cycles
Specifies the number of fatigue cycles. This option is only available when FAT is selected for Stress Types and is s not available for time history analysis.
Directives
Opens the Directive Builder dialog box, where you can control the combination method parameters, using methods such as ABS and SRSS (square root of the sum of the squares).
Add New Load Case
Adds a new load case.
Delete Current Load Case
Deletes the current load case.