Diaphragm Mass in ETABS - Reg

[Murali27]

Dear All

In the computation of diaphram mass, the forces are not matching with the story shears. Is there any bug in ETABS?

Thanks
Murali

 

[DENSAL55]

Story shear is based on modal participating mass ratio, the mass is the total mass of story.You must ask for more mode (number of mode) in calculation of your model to reach the matching value.

 

[ryansteel]

YUP! Some code says at least 90% of total mass should participate.

 

[Murali27]

Thansk a lot