Scale Factor on Response Spectrum Analysis

[zstone]

I like do perform an Response Spectrum Analysis on Etabs,
I have define a Design Spectrum By EC8 - import from file case,
and i have set a scale factor value equal to 1.0,
im i correct, because the Spectrum is defined to be Design , and is input in manual way in Etabs,
I dont like to perform automatic Seismic Case, because is not includet as well in Etabs(by EC8) - I THINK SO
can anybody help me

regards

 

[sreichwein]

Some seismic codes require the base shear of the modal analysis to be within a certain percentage of the code calculated base shear. This value is 80% in ASCE 7-05. The scale factor is used to scale the calculated ETABS base shear value to at least 80% of the code value.