2 docs tagged with "Seismic analysis"

There are many different approaches to seismic analysis. The  main approaches implemented in GSA are Equivalent Static Procedures, Response Spectrum Analysis, Linear Time History Analysis, and Nonlinear Time History Analysis. In general the response spectrum method is recommended in the various seismic codes as this is based on a dynamic analysis of the structure. However at times the simpler equivalent static method which ignores the actual dynamic response of the structure may be useful.

When a modal dynamic analysis is carried out the results are normalised to either a unit displacement or unit modal mass depending on the selection made by the user when creating the task. For response spectrum analysis these mode shapes are scaled to predict displacement values but the CQC combination procedure then combines these results across all the modes. It is useful to be able to recover directly the scaled modal values. This dialog creates a set of combination cases that correspond to the modal case scaled by the modal multiplier.