This video shows how to define load combinations in ETABS software. The earthquake load used in the load combinations is computed from the Response Spectrum Analysis (RSA).
Notes:
1 - RSA is first defined by a load case with "g" unit
2 - RSA demand forces are multiplied by I/R using a load combination called "Reduced RSA"
3 - The scaling factor (SF) is computed according to ASCE (0.85V/Vt)
4 - RSA design demands are obtained using a load combination called "Internal force" (Internal force = Reduced RSA x SF)
Upon the request of many, you can download now the excel sheets from the link below:
drive.google.com/drive/folder...