If possible please attach screen shot with your Modal analysis settings.
Maybe you use different method or ...
I am still working on the same model . But I couldn't able to get participation (90%) when I used the fixed supports under columns & walls instead of the raft foundation with springs.
Pls, Could you help me to get (90%) ? , attached is my model with fixed supports .
Thanks a lot
1. Selweigtht as mass for modal analysis duplicated in your model (1: from modal analysis settings, 2: load to mass conversion)
2. Results for such settings: