ETABS calculates the exact geometric coordinate (
These columns represent the summation of forces acting on the individual diaphragms.
The global X and Y coordinates where the mass of that specific story is concentrated. etabs mass summary by story
The total translational mass of the story acting along the Global X and Global Y directions. These values are usually identical unless directional masses or asymmetric skin loads are applied. The coordinate locations
Checks the box to include the weight of beams, columns, and slabs based on material density. ETABS calculates the exact geometric coordinate ( These
To ensure accurate and reliable results from the ETABS mass summary by story, follow these best practices:
Check the bottom story to see the total mass of the entire building. Compare this to your hand calculations (Area × Dead Load) to ensure you haven't missed any loads. These values are usually identical unless directional masses
These represent the translational mass in the global X and Y directions. In most standard buildings, these values are identical for each story. Mass Moment of Inertia (Rz):
Go to Define > Mass Source . Ensure you’ve included 100% of Dead Loads and the required percentage of Live Loads (usually 25% for storage or as per your local code).
Mastering the Mass Summary by Story is a non-negotiable skill for any structural engineer using ETABS. By applying the concepts and techniques outlined in this guide, you will be well-equipped to build accurate models and perform confident, code-compliant seismic designs.