Etabs Mass Summary By Story Jun 2026

ETABS assigns all mass within a story to the at that level. Points:

When you open the table, you will see several columns. Understanding these is vital for a precise seismic analysis:

Always perform a quick "sanity check" on the cumulative mass at the base story.

The global X and Y coordinates where the mass of that specific story is concentrated. etabs mass summary by story

The table provides the exact coordinates of the Center of Mass (Xcm, Ycm). Comparing these coordinates with the Center of Rigidity (CoR) allows engineers to calculate . If the distance between the CoM and CoR is too large, the building will experience significant twisting moments during an earthquake. 3. Diaphragm Mass Check

A good engineering practice is to perform a quick hand calculation to verify the ETABS output. Even a rough "tributary area multiplied by average dead load" check can highlight massive modeling errors. Common Issues and Solutions

A common pitfall in ETABS modeling is ensuring that all mass is correctly accounted for, especially for "null" areas (areas not part of a structural slab). If you apply loads to a null area, you explicitly assign a diaphragm to that null area for its mass to be included in the building's seismic mass for modal analysis. Otherwise, the load contributes to reactions but not to the building's mass matrix [7†L31-L34], making the structure seem lighter than it is. ETABS assigns all mass within a story to the at that level

Engineers must define a via Define > Mass Source :

These properties are calculated based on the structural elements, such as beams, columns, walls, and slabs, that make up the building.

Occasionally, loads are applied to elements that are not properly connected to the diaphragm (e.g., a beam modeled without a support connection or a slab not meshed with walls). The global X and Y coordinates where the

The name of the specific floor level being evaluated.

The is a structured table in ETABS that lists the accumulated mass of the building at each story level. This table displays the translational mass ( ) and the total weight (Peso por Piso) for each story. Mass ( ): Often in units like