Etabs Mass Summary By Story -

What are you using? (e.g., ASCE 7, Eurocode 8, NBC India) Are you dealing with rigid, semi-rigid, or no diaphragms ?

In ETABS, the is a critical output table used to verify the total weight and mass distribution of a building for seismic and dynamic analysis. How to Access the Mass Summary Table To view the story mass data after running your analysis: Navigate to the Display menu. Select Show Tables .

To help troubleshoot specific issues with your ETABS model output, please share: The (concrete, steel, or composite?)

Many users assume ETABS uses the same load combinations for mass. By default, ETABS uses Dead Load (1.0) and Live Load (0.0). For seismic design, you must define a proper mass source via: Define > Mass Source > Add New Mass Source .

Mastering the ETABS Mass Summary by Story: A Step-by-Step Guide for Structural Engineers etabs mass summary by story

The values in the mass table are not arbitrary; they are derived from the defined in ETABS. The mass source defines what makes up the "weight" of the building, which includes:

You can choose to include or exclude vertical mass. For standard lateral seismic analysis, only horizontal mass ( UXcap U cap X UYcap U cap Y ) is strictly required, though vertical mass ( UZcap U cap Z ) is necessary for vertical seismic effects. 3. How to Access the Mass Summary Table

Total Story Mass=Self Weight+Assigned Dead Loads+(ψ×Live Loads)cap T o t a l space cap S t o r y space cap M a s s equals cap S e l f space cap W e i g h t plus cap A s s i g n e d space cap D e a d space cap L o a d s plus open paren psi cross cap L i v e space cap L o a d s close paren Troubleshooting Common Mass Discrepancies

the structural period in modal analysis? What are you using

Understanding ETABS Mass Summary by Story: A Complete Guide for Structural Engineers

This data is essential for determining the center of mass ( CMcap C cap M

Right-click anywhere on the ETABS table and select Export to Excel to easily sum columns, calculate percentages, or cross-reference with your architectural area estimates.

For modal analysis (Response Spectrum or Time History), ETABS applies lateral seismic forces at the Center of Mass of each floor diaphragm. Ensuring the mass assigned to each diaphragm is realistic prevents severe under-design or over-design of the lateral force-resisting system. How to Check Mass Summary by Story in ETABS (Step-by-Step) How to Access the Mass Summary Table To

: The direct export from the Display > Show Tables > Structure Output > Other Output Items > Mass Summary by Story .

Which (e.g., ASCE 7, Eurocode 8) are you design for? Are you dealing with a torsional irregularity warning? Do you need help setting up the Mass Source definition?

). This table consolidates all mass defined in your and attributes it to specific floor levels. How to Access the Table To view the data after running an analysis: Go to the Display menu. Select Show Tables .

The is a quick yet powerful diagnostic tool. By ensuring the Mass Source is correctly defined—specifically by handling self-weight and live load percentages properly—engineers can trust the output table to verify the mass distribution essential for safe, accurate, and optimized seismic design.