Etabs Mass Summary By Story Better ((hot)) Review

Why ETABS "Mass Summary by Story" is Superior for Seismic Design

Model Explorer

Detect "ghost mass" from accidental double-counting or modeling errors. Accessing the Data To find this specific table after running an analysis: Navigate to the . Expand Tables > Analysis Results > Structure Results . Right-click Mass Summary by Story and select Show Table . Key Columns to Analyze Significance UX / UY The total translational mass in the X and Y directions. Sum UX / Sum UY etabs mass summary by story better

Assumptions

: Mention if masses were "Lumped at Story Levels" to ensure they are properly associated with floor diaphragms. 2. Primary Data Table: Story Mass Summary Why ETABS "Mass Summary by Story" is Superior

• • Columns typically include: Story name/level, Total Mass, Mass X, Mass Y, Mass Rotational (if shown), Cumulative Mass, Percentage of Total.
  • Check that cumulative mass reaches an expected percentage (codes often require ≥90% modal mass participation in primary modes).
  • Compare mass per story for unexpected peaks or drops—these may indicate missing elements or incorrect story heights.

  The software follows a specific logic to distribute mass at each level: The software follows a specific logic to distribute

  1. Open your ETABS model and ensure all loads and load cases are defined and assigned (including gravity load patterns used for mass).
  2. Run a modal analysis (Response Spectrum/Modal time history) or at least a mass-consistent modal extraction.
  3. From the menu: Display → Show Tables → Masses → Story Mass Summary (menu names may vary slightly by ETABS version).
  4. Select the load cases/patterns to include (e.g., Dead + portion of Live if required by code).
  5. Export the table to CSV or spreadsheet for reporting.

  2. Live Load Clauses Are Ignored

  4. The 7-Step Validation Checklist for a "Better" Summary