In structural engineering, mass is the fundamental property that drives the inertia of a building during an earthquake. The in ETABS is a tabular output that provides a clear, numerical breakdown of your structure’s mass and weight on a story-by-story basis.
Do you have any specific questions about using this feature or interpreting the results?
Multiply it by an estimated average dead load intensity (e.g., depending on the usage and structure type).
The natural periods of vibration of your building are highly dependent on the mass and stiffness distribution. Mass that is improperly lumped into the wrong stories will result in erroneous dynamic characteristics. How to Define and Extract the Mass etabs mass summary by story
Engineers check this table to ensure the Total Weight matches their manual calculations for base shear. If the total mass is too low, the calculated seismic forces will be underestimated, leading to unsafe design. B. Identifying Torsional Issues
Allows you to add joint/frame loads (like partition loads) to the mass.
Spot sudden spikes or drops in story mass caused by accidental duplicate elements or missing area assignments. In structural engineering, mass is the fundamental property
The Mass Summary by Story is essential for:
Which (ASCE 7, Eurocode, etc.) you're following
The program constructs the mass matrix based on the specified mass source, allowing it to accurately perform dynamic, spectral, and time-history analyses. Why is "Mass Summary by Story" Important? Multiply it by an estimated average dead load intensity (e
Determines the stability and secondary moments of the frame.
After you verify the mass summary, run a modal analysis. The report depends entirely on the Mass Summary.
: Converts assigned loads (e.g., Dead Load + a percentage of Live Load) into mass by dividing the weight by the gravitational multiplier ( ). For example, codes like IS 1893:2016 often require Dead Load plus Live Load depending on load intensity. 4. Mass Lumping Mechanics