Effective seismic weight and the lumped mass at the center of each story in ETABS (Lec9)

This video shows how to compute the effective seismic weight and the lumped mass at the center of each story manually. Please do not use the wall auto-mesh option because masses will be lumped incorrectly!!!
Upon the request of many, you can download now the excel sheets from the link below:
drive.google.c...

[@husseinibrahim1228]

Very clear explanation, 👌

[@AA-hr3ul]

thnk you tarek

[@zuhairdema]

Dear Engineer its allowed for the building to be bigger than the other stories,,, as i see in your model there’s a five story as basement extended then 8 stories smaller then the rest of the tower is smaller in area it’s acceptable,,, since i guess its not allowed and you should have an expansion joint between the tower and the rest of the story if they are bigger in elevation

[@Eng.tarekyoussef]

Thank you for your observations. Here are my clarifications regarding the structure:
No Basement:
In this project, there is no basement; all stories are above ground.
Irregular Building Design:
This building has an irregular shape. While using expansion joints can enhance the structural response, the current model was studied without expansion joints to understand potential issues within this system.
High Load Transfer at Podium Level:
In such structures, significant load transfer occurs at the podium level, especially where there is a change in the floor plan layout. If this building were to be constructed, we would add expansion joints. This would divide the structure into several pieces, thereby reducing the intensity of the transferred forces at critical levels.

[@NguyenSon-hx6pj]

really appreciate !

Why it is wrong if the mass is not lumped at the floor level. In fact there are two different mass matrix coupled and uncoupled or lumped and consistent. With shear walls mainly the consistent mass matrix is likely to be correct because the mass of vertical elements slightly smaller than or equal the mass of the floor then there is no point to lump the mass at the floor level.

[@Eng.tarekyoussef]

ETABS does not lump the masses correctly to floor level if the mesh option for shear wall is used. This issue is also announced through the CSI website.
In reality, the mass of a building is not only concentrated at the floor levels but is distributed throughout the structure. Lumping masses at the center of each floor, which is done by the use of a rigid diaphragm, is an approximation to simplify the analysis.
Thus, the mass matrix generated in ETABS will be affected by the way the masses are lumped.

[@herribreej9375]

سلام صديقي .. تعرف تسوي TMD on Etabs

[@Eng.tarekyoussef]

I never did that

[@Nikesh977]

We do not get mass data in etabs 17 , do we?

[@Eng.tarekyoussef]

All ETABS versions are similar with minor differences. Try the newer version!