By Story Verified | Etabs Mass Summary

: Define this under Define > Mass Source . You must specify whether to use element self-mass, additional mass, or specific load patterns (like 100% Dead Load + 25% Live Load).

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 etabs mass summary by story

ETABS generally "lumps" masses at the floor levels to simplify the analysis into a Multiple Degree of Freedom (MDOF) system. Mass - CSI Knowledge Base : Define this under Define > Mass Source

Spot sudden spikes or drops in story mass caused by accidental duplicate elements or missing area assignments. Mass - CSI Knowledge Base Spot sudden spikes

Interpretation of the "Mass" column is key. This value is the result of the mass source calculation applied to all elements and loads tributary to that story's diaphragm. The accuracy of this data is paramount for all subsequent dynamic procedures.

To ensure reliable results, follow these best practice recommendations: