The Mass Summary by Story report provides the following information:
It helps you verify which parts of the structure (e.g., superstructure vs. substructure) are contributing to specific Modal Mass Participation Ratios . Where to Find It You can access this table by following this path in ETABS: Go to the Display menu. Select Show Tables .
Underestimated mass leads to underestimated base shear, leading to an unsafe design.
2. Setting Up for a "Better" Mass Summary (Mass Source Definition)
) under dead load cases to the total cumulative mass. These should align closely; a significant discrepancy often indicates unassigned masses.
Seismic design is a battle against torsion. The Mass Summary report typically includes the coordinates for the Center of Mass
Dynamic lateral analysis requires an accurate Center of Mass (CM) and Center of Rigidity (CR) to calculate torsional effects. Inspecting individual nodes to find the balance point is impractical.
The total mass participating in the X or Y direction. Xcmcap X sub c m end-sub Ycmcap Y sub c m end-sub : The location of the Center of Mass. Xcm,cumcap X sub c m comma c u m end-sub Ycm,cumcap Y sub c m comma c u m end-sub : The cumulative center of mass up to that story. 4. Strategies for Better Seismic Modeling A. Identify Mass Irregularities Early
In this article, we will move beyond the default settings. We will explore how to extract, validate, and optimize the ETABS Mass Summary by Story to ensure your dynamic analysis (Response Spectrum, Time History) and modal results are physically accurate.
To utilize this workflow for your next project quality check, locate the table through the standard results tree: Analyze your model ( F5 ).
In your structural report, include:
The mass of your building is the primary driver of inertial forces during an earthquake. The Mass Summary by Story report serves several high-stakes engineering purposes:
If you have a mechanical penthouse, the default summary lumps the penthouse floor mass into the roof story below it. This makes it look like your roof weighs 2x what it should. Better means decoupling these.
By mastering the ETABS mass summary by story feature and incorporating the tips and best practices outlined in this article, engineers can take their structural analysis and design skills to the next level, creating better buildings that are safer, more efficient, and more sustainable.
Etabs Mass Summary By Story Better Portable
The Mass Summary by Story report provides the following information:
It helps you verify which parts of the structure (e.g., superstructure vs. substructure) are contributing to specific Modal Mass Participation Ratios . Where to Find It You can access this table by following this path in ETABS: Go to the Display menu. Select Show Tables .
Underestimated mass leads to underestimated base shear, leading to an unsafe design.
2. Setting Up for a "Better" Mass Summary (Mass Source Definition) etabs mass summary by story better
) under dead load cases to the total cumulative mass. These should align closely; a significant discrepancy often indicates unassigned masses.
Seismic design is a battle against torsion. The Mass Summary report typically includes the coordinates for the Center of Mass
Dynamic lateral analysis requires an accurate Center of Mass (CM) and Center of Rigidity (CR) to calculate torsional effects. Inspecting individual nodes to find the balance point is impractical. The Mass Summary by Story report provides the
The total mass participating in the X or Y direction. Xcmcap X sub c m end-sub Ycmcap Y sub c m end-sub : The location of the Center of Mass. Xcm,cumcap X sub c m comma c u m end-sub Ycm,cumcap Y sub c m comma c u m end-sub : The cumulative center of mass up to that story. 4. Strategies for Better Seismic Modeling A. Identify Mass Irregularities Early
In this article, we will move beyond the default settings. We will explore how to extract, validate, and optimize the ETABS Mass Summary by Story to ensure your dynamic analysis (Response Spectrum, Time History) and modal results are physically accurate.
To utilize this workflow for your next project quality check, locate the table through the standard results tree: Analyze your model ( F5 ). Select Show Tables
In your structural report, include:
The mass of your building is the primary driver of inertial forces during an earthquake. The Mass Summary by Story report serves several high-stakes engineering purposes:
If you have a mechanical penthouse, the default summary lumps the penthouse floor mass into the roof story below it. This makes it look like your roof weighs 2x what it should. Better means decoupling these.
By mastering the ETABS mass summary by story feature and incorporating the tips and best practices outlined in this article, engineers can take their structural analysis and design skills to the next level, creating better buildings that are safer, more efficient, and more sustainable.