Etabs Mass Summary By Story New! Jun 2026

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: Floating or unattached elements will still contribute to the story mass if they are assigned to that story level, even if they do not transfer load structurally.

is checked to account for translational mass in X and Y directions. 2. View the Mass Summary Table

When reviewing the table, the most immediate metric is the vertical consistency of mass per story. A building follows the laws of physics; typically, lower stories have larger masses due to bigger column sections, thicker shear walls, and heavier floor plates, tapering off as the building rises.

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. etabs mass summary by story

Suggests a strong base, but if lateral walls are not designed properly, this could lead to base shear issues.

In the realm of structural engineering software, CSI ETABS (Extended Three-dimensional Analysis of Building Systems) stands as a cornerstone for the analysis and design of building systems. Among the myriad of output tables and log files it generates, one of the most critical—yet often overlooked—is the .

The is an indispensable diagnostic tool for structural engineers. It bridges the gap between raw finite element modeling and the macro-level physics governing seismic design. By routinely checking this table, verifying the Center of Mass coordinates, and validating the total building weight against hand calculations, you ensure that your structural model is safe, code-compliant, and ready for advanced lateral design. To help tailor further engineering workflows, If you are interested, I can:

calculations, one can ensure that the software is correctly interpreting the load patterns. Furthermore, this data is the primary input for determining the building’s natural periods mode shapes Let me know how I can further assist

To ensure your model is accurate, follow this standard verification workflow using the table data: Step 1: Hand Calculation Comparison

If your story mass summary looks incorrect, check the following modeling areas:

Follow these steps to extract and analyze the story mass data from your ETABS model: Step 1: Define the Mass Source Correctly

Double-click to open the interactive data table. Right-click anywhere on the ETABS table and select

This usually happens when "Element Self-Mass" is checked in the Mass Source and the Dead Load pattern (which already includes a self-weight multiplier of 1) is added to the load list. Uncheck element self-mass or fix the load pattern multiplier. Abrupt Spikes in Center of Mass: If the

Conversely, a sudden drop in mass might indicate missing elements—such as a floor slab that failed to mesh or was accidentally deleted in plan view.

Compare modeled weight against manual calculations to meet quality assurance requirements.

If your mass seems too low, check your Mass Source definition. Ensure you included a percentage of the live load (typically 25% for storage warehouses) if required by your local building code. Double Counting Mass

At its core, the Mass Summary by Story is a tabulated report that calculates and displays the total mass and weight (W) for each floor level of your model. ETABS automatically computes these values based on the assigned dead loads, live loads, superimposed dead loads, and mass source definitions.