: Vertical mass (included if "Include Vertical Mass" was selected in the Mass Source). Sum UX / Sum UY : Cumulative mass from the top down to that specific story. : The equivalent weight of the story mass (Mass × Computers and Structures, Inc. 4. Verification Tips Manual Check
When the report loaded, the first line showed the total seismic weight per story. Maya read it like a heartbeat: lower floors carried more—concrete podiums, parking slabs, and heavy mechanical rooms—while the upper residential stories were lighter, filled with drywall and furniture assumptions. The variation was clear in the table: Story 1 held 1,200 kN, Story 2 had 1,000 kN, and by Story 12 it tapered to 650 kN. The building’s center of mass whispered its position: slightly offset toward the west because of the heavier stair core. etabs mass summary by story
This is the rotational mass (polar moment of inertia) about each axis. : Vertical mass (included if "Include Vertical Mass"