Very Low Base Shear and Sign to be used for Loads

Dear All,

I hope you are all doing well. I am in the middle of a crucial assignment for which I am doing Response Spectrum analysis using custom spectrum.

Base Shear and load sign.txtSeismic Spectrum.xlsx

Client has provided the Ct and x values only. I am having the below queries.

1. The base shear value i am getting is too low for the structure.

2. I want to know if the signs for loads in Definition of loads are correct.

3. Also, i would like to know if the scale of 9.81 is correct? (I am always confused about it ). I have attached the spectrum calculation - Note the Ao term has a g term (0.4g) hence, Sa/g is calculated for spectrum

Thanks a lot in Advance.

Best Regards,

PNP