The purpose of DIRECT ANALYSIS is to compute the member forces for strength design. For computing drifts, deflections you should use a PDELTA 15 ANALYSIS with the un-reduced stiffness and not a DIRECT ANALYSIS. Both analysis commands could be part of…

The easiest would possibly be to use the IMR command in your spectrum case. Here is an example LOAD 4 LOADTYPE None TITLE LOAD CASE 4 SELFWEIGHT Y 1 SELFWEIGHT X 1 SELFWEIGHT Z 1 SPECTRUM SRSS IBC 2006 X 1 ACC DAMP 0.05 LIN IMR 10 STARTCASE 101 ZIP…