Etabs Mass Summary By Story

The translational mass active in the horizontal X and Y directions. This is calculated from your defined Mass Source.

). If your Mass Summary shows significantly lower values than your manual "take-off" calculations, your seismic base shear ( ) will be underestimated, leading to an unsafe design. 2. Identifying Modeling Errors

Alternatively, you can access this via the top menu: . Deconstructing the Table Columns

A very specific topic!

Any lumped masses explicitly assigned to joints or frames by the user.

Are you seeing a between your hand calculations and ETABS?

the structural period in modal analysis? etabs mass summary by story

Alternatively, you can access this via the top menu: Display > Show Tables , then check the box for under the Structure Results tree. Interpreting the Table Columns

If your floor slabs are not assigned to a diaphragm, their mass will still be calculated, but it will not be lumped at a single Center of Mass point. This can affect how lateral wind and seismic forces are applied to the story.

Ensure your model is fully analyzed (press F5 ). The translational mass active in the horizontal X

By mastering the Mass Summary by Story table, you ensure your dynamic structural analysis stands on a structurally sound, perfectly weighted foundation.

In ETABS, the program does not automatically guess which loads contribute to the seismic mass. You must define a mass source under .

The ETABS Mass Summary by Story is not just another output table; it is your model's . Before you invest hours interpreting drift ratios or designing rebar, spend two minutes reviewing this summary. If your Mass Summary shows significantly lower values

, the total mass in your ETABS summary (multiplied by gravity) should match your hand-calculated dead loads and applicable live load percentages. B. Spotting Modeling Errors