Etabs Mass Summary By Story Better -
This article explores how to extract, interpret, and troubleshoot the Mass Summary by Story table to ensure your structural models are code-compliant and structurally sound. Why Mass Verification Matters
You start at the bottom. This is your . You recruit the heaviest, strongest Sumo wrestlers you can find. They are massive.
) and compare it with the ETABS table. The results should match closely. Tip: Remember to convert between kilograms ( ) and tons ( ) if necessary. 5. Troubleshooting Mass Summary Discrepancies
. A sudden spike or dip in mass between floors can signal a modeling error or a significant architectural change that will disproportionately attract seismic forces, helping to catch "soft story" or "weight irregularity" issues early. 2. Direct Verification of the "Mass Source" etabs mass summary by story better
The rotational mass about the Z-axis.
The mass moments of inertia. RZ is especially crucial for seismic engineering, as it dictates the rotational inertia of the floor during a torsional ground motion response.
Instead of checking thousands of individual nodes, the story summary aggregates data into a single line per floor. This allows you to instantly spot anomalies—such as an unexpectedly heavy roof or an unnaturally light podium level—in seconds rather than hours. 2. Center of Mass (COM) Tracking The table explicitly calculates the This article explores how to extract, interpret, and
| Story | Mass X (kg) | Mass Y (kg) | Total Mass (kg) | Cumulative % | |-------|-------------:|------------:|----------------:|-------------:| | Roof | 12,000 | 11,500 | 23,500 | 5.2% | | 10 | 24,000 | 23,000 | 47,000 | 15.6% | | ... | ... | ... | ... | ... | (Export actual values from ETABS for your project.)
aggregates all structural and non-structural loads—including dead loads and specified live load reductions—into a single value per level. This allows an engineer to immediately identify mass irregularities
) of the Center of Mass for each floor. This is critical for evaluating accidental eccentricity and torsional vulnerability. How to Access the Mass Summary Table in ETABS You recruit the heaviest, strongest Sumo wrestlers you
You’ve built a better ETABS mass summary by story. Now, what does it tell you?
An error in mass modeling—such as double-counting live loads or missing self-weight—will lead to incorrect design forces. The Best Way to Check Mass: Mass Summary by Story
: The total mass of the current story plus all stories above it. This is highly useful for checking shear base calculations. Engineering Best Practices for Mass Verification
The default is a starting point, not a finish line. A better mass summary is one that:
