In a response spectrum Why we use the 1st scale factor Ig/2R in ETABS 16?

I am Doing project on scale factor. i.e. base shear scale factor. in the manually calculation we dident use any type of 1st scale factor but in etanb 16 we use 1st scale factor as the Ig/2R. also...

21 January 2019 7,276 7 View