Etabs Mass Summary By Story -

): The core of any equivalent static lateral force procedure relies on the total seismic weight of the structure. By summing the weights of all stories, you get the total base shear weight, which must comply with building codes (e.g., ASCE 7, UBC).

Engineers check this table to ensure the Total Weight matches their manual calculations for base shear. If the total mass is too low, the calculated seismic forces will be underestimated, leading to unsafe design. B. Identifying Torsional Issues etabs mass summary by story

Are you encountering a between your manual calculations and ETABS? ): The core of any equivalent static lateral

Note on RZ: represents the torsional mass moment of inertia. This value dictates how the building twists during a seismic event and is critical for evaluating accidental eccentricity and torsional irregularities. Step-by-Step Mass Verification Workflow If the total mass is too low, the

She checked vertical mass contribution: slabs and partitions dominated, and the elevators concentrated mass at the core. The rigid diaphragm assumption held—floor masses were lumped at the diaphragm level—so any local stiffness irregularity could amplify torsion. Maya made notes: reduce eccentricity by rebalancing the core layout, or add a small shear wall on the east face to shift mass center.

When you run the analysis and navigate to , you will see a table with the following key columns: