scaling up of base shear

[KaremHajj]

Dear all ,

i have a 19 floors building and i am using Etabs for seismic analysis,i am starting a g/R (R=4) as minimum scale factor for response spectrum case ,but when comparing the base shear between static and dynamic the ratio V(static)/Vdynamic =6>R,thus the scale factor for spectral case is (g/R)*(ratio) that give a value greater than g.what shall i do in this case.

thanks in advance .

 

[haynewp]

Assuming the rest of you analysis is correct and using AISC 7, AISC requires scaling the base shear according to 12.9.4 when the base shear from the dynamic analysis is less than 85% of the equivalent static base shear.

 

[KaremHajj]

i know that i should do a scaling but there is a maximum value for this scale =g;in my case the scale is greater than g.

 

[slickdeals]

Something is wrong.