Cracked section properties for inelastic elements in RSA

[ashtari]

I have utilized inelastic displacement-based fibre section frame elements in my model. I am running response spectrum analysis, which is basically elastic analysis. I was wondering if Seismostruct uses the elastic section properties, how I can modify the stiffness values to account for the cracked sections.

Thanks

[huffte]

Hi ashtari. Response spectrum analysis is, by its very nature, elastic. So yes, the demands are elastic demands. While you may reduce Young's modulus for the material to account for cracked section properties, the ensuing demands will still be, strictly speaking, elastic. RSA will not capture inelastic behavior in the fibers.

Best of luck, ashtari.

[MSWC]

I have another question concerning this topic.

How does the RSA functions with the infill panel element? Does the initial stiffness of the inifll element define the reaction?

[seismosoft]

Due to a bug in the RSA procedures of the infill element, its stiffness is not considered in the current version of SeismoStruct. The bug will be corrected in the upcoming Release-6 of SeismoStruct 2016.

Seismosoft Support

[MSWC]

Thank you, but in the case the bug is fixed, which parameters of the infill panel would be considered in the RSA?