Etabs Mass Summary By Story | !!hot!!

The resulting table provides a clear breakdown, usually organized from the highest story down to the base. Setting Up the "Mass Source" Correctly

The most common mistake engineers make is forgetting to define the Mass Source. By default, ETABS uses only the self-weight of the structure. You must manually add superimposed dead loads and a percentage of live load (e.g., 25% for parking, 50% for office storage as per ASCE 7).

The output will be presented as a spreadsheet-style table that can be exported, copied, or included in design reports.

The coordinates representing the "centroid" of the mass for that specific story. This is used by ETABS to calculate accidental eccentricity and torsional effects. etabs mass summary by story

To view the Mass Summary by Story in ETABS, follow these step-by-step instructions after running your structural analysis:

Below is a drafted report structure for presenting this data. Structural Mass Summary Report 1. Project Overview ETABS 2026 Model Status: Analysis Completed Mass Source: Defined as [e.g., Self Mass + 25% Live Load] 2. Mass Source Definition

: The vertical mass active in the global Z direction (only populated if vertical mass is included in your mass source). The resulting table provides a clear breakdown, usually

(Vertical Mass): The mass active in the vertical direction (often ignored for standard seismic lateral loads but necessary for vertical dynamic evaluations).

: The torsional mass moment of inertia about the vertical Z axis, which is crucial for determining the building's fundamental torsional modes.

used to verify a building's seismic weight and dynamic characteristics. It provides a tabulated breakdown of the total mass attributed to each floor level, which is essential for calculating seismic base shear and ensuring the accuracy of the structural model. 1. Definition and Source of Mass The values in the story mass summary are derived from the Mass Source defined by the user. Element Self-Mass You must manually add superimposed dead loads and

The table contains several columns that represent different directional forces and mass locations. Understanding these terms ensures correct interpretation of your model. : The specific floor level being reported.

The Mass Summary by Story is not merely a data table but the foundation of a building's seismic "identity." By meticulously reviewing these values, an engineer ensures that the mathematical model accurately reflects the physical reality of the structure, leading to a safe and optimized design.