The Center of Mass coordinates; compare these to the Center of Rigidity. How to Improve Your Mass Source Setup
Seismic forces are calculated based on mass. If your story mass is off, your base shear and lateral forces will be incorrect. This table allows you to: Verify the self-weight of slabs, beams, and columns.
Ensure you haven't modeled a slab over a slab, which doubles the mass in that specific story. etabs mass summary by story better
For better results, your "Mass Source" definition should follow these industry standards:
Typically, use 1.0 for Dead/SIDL and 0.25 for Live Load (depending on your local building code). The Center of Mass coordinates; compare these to
Cumulative mass from the top down; used to check total building weight.
If your Mass Summary by Story looks "wrong" compared to your manual hand calculations, check these three areas: This table allows you to: Verify the self-weight
Check if superimposed dead loads (SIDL) are applied correctly.