Etabs Mass Summary By Story May 2026

But here is a hard truth:

The "Where is my Mass?" Mystery Here is the most common panic moment for engineers: "I assigned a 10-inch slab, beams, columns, and walls... so why does the Mass Summary show almost nothing on the roof?"

If you modeled a concrete slab but forgot to assign Self Weight Multiplier = 1 (under ), ETABS will only include the superimposed dead loads (finishes, partitions) and completely ignore the 150 pcf concrete you just modeled.

He forgot to check the Mass Summary. The summary showed that 70% of the building's mass was concentrated on the 5th floor (UX value was huge). No amount of shear walls on floors 1-4 could fix that torsion without massive foundation changes. He had to add stiffness at the 5th floor .