Most building codes (such as ASCE 7, Eurocode 8, or IS 1893) calculate lateral seismic forces based on story weights ( Wicap W sub i
Go to Define > Mass Source . Do use "From Self and Specified Loads" without modification unless you are certain.
Ensure all slabs have the correct thickeness assigned. etabs mass summary by story better
Master Structural Verifications: Why ETABS Mass Summary by Story is Better
To get the most accurate summary, you must first define the mass source correctly. Most building codes (such as ASCE 7, Eurocode
Before we can make it better, we must understand what the software is doing under the hood.
To ensure your model is correct, perform these three quick checks using the table data: Master Structural Verifications: Why ETABS Mass Summary by
This article will show you exactly how to generate a , interpret the hidden variables, and troubleshoot mismatches before your plan check.
| Observation | Diagnosis | Fix | |-------------|-----------|-----| | Mass on roof > floor below | Penthouse mass merged into roof | Split story definition | | Mass at basement is huge | Soil interaction mass included | Check mass source: exclude soil | | Mass not integer (weird decimals) | Shell meshing causing partial masses | Remesh with regular grid | | Lateral stiffness unreasonably low | Missing diaphragm constraint | Assign Rigid Diaphragm | | Mass changes between Ultimate & Service | Different load multipliers | Set both to seismic combo |
