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Analysis Types
- PERFORM-3D can run the following analysis types:
- Mode shapes, periods, and effective mass factors.
- Gravity load.
- Static push-over.
- Response history for earthquake ground motion.
- Response history for dynamic forces.
- Response spectrum analysis (with limitations).
- The nonlinear analysis strategies are very reliable, even when inelastic components have negative stiffness, and when P-delta effects cause the structure to become unstable.
Analysis Sequence
- The most common analysis sequence is:
- Apply gravity loads.
- Run one or more static push-over analyses, with constant gravity load.
- Run one or more earthquake response history analyses, with constant gravity load.
- This is a “standard” sequence. A “general” sequence can also be applied, for example cyclic push-over as follows:
- Apply gravity loads.
- Add push-over loads to a specified drift in the positive direction.
- Add push-over loads to a specified drift in the negative direction.
- Etc., progressively increasing the specified drift in each direction.
Analysis Series
- An “analysis series” is a series of analyses, with a standard or general analysis sequence. For each analysis series, the following structure properties can be changed:
- The mass distribution and magnitude. This can affect static push-over analysis as well as dynamic response history analysis.
- The amount and type of damping for dynamic response history analysis.
- The strengths and stiffnesses of the structural components (within certain limits).
- This allows you to change the structural properties without setting up a new analysis model.
