: Mass moments of inertia about the global axes, critical for torsional calculations.
For response spectrum or time history analysis, the Mass Summary is your truth serum. Compute the from the modal analysis. The Mass Summary gives you the total mass of the building. The modal output gives you the effective modal mass.
The portion of the floor mass assigned directly to a rigid or semi-rigid diaphragm.
table is generally the superior and more reliable choice for extracting the total seismic weight of a structure. Direct Comparison: Story Mass vs. Diaphragm Mass Mass Summary by Story Diaphragm Mass Summary Scope of Mass mass assigned to the story (slabs, beams, columns, walls). etabs mass summary by story better
This will generate a clear grid displaying your stories, their respective masses in orthogonal directions, and the mass moment of inertia ( MMIcap M cap M cap I 🔍 Why the Mass Summary by Story is So Critical
: Briefly describe the structure, including the number of stories, heights, and general building type.
Forgetting to include the self-weight of structural elements or finishes. : Mass moments of inertia about the global
coordinates of the Center of Mass for each story. Tracking the COM relative to the Center of Rigidity (COR) is vital for minimizing accidental torsion. Seeing this data organized by story makes eccentricity trends immediately obvious. 3. Seamless Diaphragm Integration
: Ensure your model is fully analyzed (press F5 ). Open Output Tables : Navigate to Display > Show Tables .
To help tailor further structural optimization strategies, what specific or lateral force-resisting system are you currently designing? Share public link The Mass Summary gives you the total mass of the building
) 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
Torsional effects and accidental eccentricities are calculated relative to the center of mass at each story.