After the restrained weight case, CAESAR II runs an operating analysis. If there are multiple operating conditions, the software recommends the load cases it thinks you should run. This is a linear or a nonlinear analysis, as discussed below.
To find the hanger displacement, the software runs a linear analysis:
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Removes the Y-restraints at any anchors.
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Uses the calculated load from the restrained weight analysis and applies it as an upward force at each hanger location.
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Calculates the expected travel and additional load on the hanger.
The vertical displacement of the operating case at a hanger location defines the travel of the hanger.
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Selects a hanger from the catalog meeting the calculated load and travel values.
If the analysis results in single directional restraints or gaps in the system and a changed status in the operating case, then the software redistributes the hanger loads. For example, as the temperature of a pipe increases, the pipe may lift from a single-direction restraint, such as the support shown in the following graphic. When this occurs, the hanger sees additional load.
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For a nonlinear status change, such as a pipe lifting off a restraint, the software designs the hanger for Maximum Load:
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Reruns the restrained weight case with the restraints left as they were at the end of the operating case.
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Recalculates the new restraint loads.
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Runs another operating case.