Etabs Mass Summary By | Story Better

Let’s compare a 6-story concrete building example.

The ETABS Mass Summary by Story is not just a diagnostic tool—it is the foundation of your seismic safety. To make it better, you must:

The next time you run ETABS, spend 15 minutes on the Mass Summary. Compare it, question it, and improve it. Your future self—and the building's occupants—will thank you. etabs mass summary by story better

About the Author / Further Resources: For a deep dive, download the official CSI Analysis Reference Manual (Chapter 3: Mass and Weight). Or, check your local building code (ASCE 7, IBC, Eurocode 8, IS 1893) for specific mass combination factors—they vary, but the principles above remain universal.

Now, the exported table alone is still not great. Create an Excel pivot table that: Let’s compare a 6-story concrete building example

Your custom table should have these columns: | Story | Mass DL (kip-s²/in) | Mass LL (reduced) | Mass Total | Seismic Weight (W) | Cumulative W | |-------|---------------------|-------------------|------------|--------------------|---------------|

The Scenario: A firm in a high-seismic zone (Seismic Design Category D) ran ETABS and got a base shear of 1,500 kips. The design was proceeding. The next time you run ETABS, spend 15

The Problem: A junior engineer noticed the Mass Summary by Story showed only 1,200 kips of mass at the ground floor, while the architectural takeoff showed 1,800 kips.

The Investigation:

The Fix: They updated the mass source to include PARTITION and converted cladding to Additional Mass. The new Mass Summary showed a 28% increase in seismic weight.

The Result: Base shear increased from 1,500 kips to 2,100 kips. The original columns were undersized. A potential collapse was avoided.