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General

How is the response spectrum created from acceleration records?

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Answer: The output of a response spectrum analysis is the likely maximum response to a given loading. This is described in detail in CSI Analysis Reference Manual, chapter "Response Spectrum Analysis", section "Overview". If your structure is symmetrical about a plane of y = constant, then the response you are getting is expected, since both the structure and the loading are symmetrical about the same plane and a single positive result is produced for each joint displacement.

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