I am currently working on an IBC 2012 project where I am using the response spectrum command to define the seismic loads. I am working on a 3-D model with three rows of columns in the direction of the seismic load.
I have specified a CQC combination method and the Ss and S1 values manually. I am scaling the spectrum by a factor of 0.625 for the x-direction (I/R where I =1.25 and R=2) with linear interpolation and 5% damping.
When I review the reactions output, all I see are column Fy (vertical) reactions acting in the same direction (positive). I would expect to see one of the end columns to have a negative reaction for the overturning moment uplift. What input am I getting wrong?