What are the scale factors used for in defining Response Spectrum cases?
Response-spectrum data, as well as acceleration time-history records, are often provide in g’s, so they need to be scaled into ft/s^2, or whatever are the current length/time^2 units. Once the scale factor is set in the response spectrum case, it is automatically adjusted if the length units are changed. Additional scaling can be applied for design purposes. For example, one way response spectrum results are sometimes scaled is to match the same base shear as is provided by equivalent lateral static analysis, under the presumption that static results provide the overall magnitude, but the response spectrum provides better distribution due to multiple mode effects.
