When using Element Self Mass , ensure that your Mass Source does not also have a "Dead Load" pattern activated with a self-weight multiplier of
Non-structural elements like parapet walls, water tanks, or heavy facade elements must be added to the mass source. etabs mass summary by story better
Select "From Self and Specified Load Patterns" and create a custom combination: When using Element Self Mass , ensure that
If you haven't assigned a rigid diaphragm to your floors, the mass summary might not accurately represent the floor-level mass distribution, leading to incorrect seismic load distribution. 5. Summary Checklist for Accurate Mass Ensures correct inputs ( Verify Floor Area Ensures slabs are modeled correctly. Inspect Table Data Look for unexpected zeros or massive jumps in mass. Check Ensure mass is centered correctly, not skewed. Compare with Total Does the sum of story masses match the total building mass? Summary Checklist for Accurate Mass Ensures correct inputs