Click Sa(T) ← F(t) in the Points tab of the Spectrum definition dialog to open the Response spectrum calculations dialog. From here you can determine the response spectrum Sa=Sa(T) for a given acceleration diagram F(t), where T refers to period, Sa refers to acceleration spectrum, t -refers to time while F(t) is a given time analysis function.
The dialog box consists of the following tabs.
See also:
Theoretical basis for response spectrum calculations in spectral analysis