Etabs Mass Summary By Story |work| -

If a story shows a mass significantly higher or lower than expected, it’s a red flag. Common culprits include:

The geometric coordinates where the story mass is concentrated.

Whether you are checking for modeling errors or prepping data for base shear calculations, here is everything you need to know about the Mass Summary by Story table. 1. How to Access the Mass Summary Table etabs mass summary by story

, the total mass in your ETABS summary (multiplied by gravity) should match your hand-calculated dead loads and applicable live load percentages. B. Spotting Modeling Errors

If your "Mass Source" (Define > Mass Source) is set to include "Element Self Mass" AND "Loads," but you’ve also manually assigned mass, you might be double-counting. If a story shows a mass significantly higher

Seismic codes (like ASCE 7 or Eurocode 8) calculate the base shear based on the total "Seismic Weight" (

Ensure your Dead Load pattern has a self-weight multiplier of 1, so the program automatically includes the weight of beams, columns, and slabs. 5. Exporting for Documentation Spotting Modeling Errors If your "Mass Source" (Define

The center of mass for the entire structure from that story upward. 3. Why This Data Matters A. Seismic Base Shear Verification

By comparing the from this table to the Center of Rigidity (CR) (found in a separate table), you can determine the structural eccentricity. High eccentricity leads to significant torsional (twisting) effects during an earthquake. 4. Tips for Accurate Mass Results