By Story Better ((full)): Etabs Mass Summary

Check if superimposed dead loads (SIDL) are applied correctly.

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.

Interpreting between the Center of Mass and Center of Rigidity. etabs mass summary by story better

When you use ETABS for high-rise or complex structures, simply looking at the total mass isn't enough. You need to ensure the distribution aligns with the structural intent. Why Mass Summary by Story Matters

If your Mass Summary by Story looks "wrong" compared to your manual hand calculations, check these three areas: Check if superimposed dead loads (SIDL) are applied

Detect "ghost mass" from accidental double-counting or modeling errors. Accessing the Data To find this specific table after running an analysis: Navigate to the . Expand Tables > Analysis Results > Structure Results . Right-click Mass Summary by Story and select Show Table . Key Columns to Analyze Significance UX / UY The total translational mass in the X and Y directions. Sum UX / Sum UY

Ensure you haven't modeled a slab over a slab, which doubles the mass in that specific story. This table allows you to: Verify the self-weight

Typically, use 1.0 for Dead/SIDL and 0.25 for Live Load (depending on your local building code).

Cumulative mass from the top down; used to check total building weight.

Mass moments of inertia; critical for capturing torsional effects.