Rigid floor diaphragm with nonlinear elements

[sumitanand]

Hello,

I have looked at the presentation 'Modeling Diaphragms in 2D Models with Linear and Nonlinear Elements' by Vesna Terzic.

But if you take away the rigid diaphragm constraint for nonlinear RC frames, the number of free dofs increases which gives unrealistic mode shapes? How do you overcome this problem?

Regards

Sumit

[vesna]

if in 3D you can use elastic truss elements with high stiffness (equivalent to floor axial stiffness) to model the diaphragm.