Etabs Load Case with Response Spectrum for a 0.25g ground acceleration

[Joseph Daou]

Hi,
I have a project where i have ground acceleration of 0.25g and i have to make the model (a building of 36 story) my question is in the load case for the dynamic analysis (Response spectrum analysis) do i input a scale factor of 0.25g or should i just keep it g ?
My main objective here is to compare a point masse model analysis with ETABS FEM but i keep getting dynamic shear < than static shear.
but in y point mass analysis i have dynamic shear > static shear
so i was confused if there anything to do with 0.25g in the load case or is it just for the response specrum of the UBC 97

Another question would be that i use 0.25g to draw my own response spectrum and extract Sv (speed from the spectrum) to get the displacement acceleration forces .... how can i enter my response spectrum in Etabs because the UBC 97 spectrum is different than the one i am working with

 

[Joseph Daou]

Thanks for any reply i forgot that