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Compression only

Compression only

Compression only

Hi guys,
I am doing a response spectrum analysis, and I want some elements to carried compression loads only. I read from ETABS help that there is a feature that name Tension/Compression Limits but this option is working only for nonlinear analyses (mention in help menu). since the response spectrum analysis is a linear analysis. I would like to know, how can I make the elements to work only in compression using this analyses.

RE: Compression only

Response Spectra analysis is inherently a linear analysis. So, you can't have non-linear elements.

Note: Your stiffness will be linear as well for a response spectra analysis. Though, it may be based off of a non-linear load case that accounts for P-Delta softening.

What kind of compression only elements are you thinking of? Compression only soil springs?

RE: Compression only

If you are talking about tension or compression only members, in the past I've run a non-linear analysis with nominal lateral load to effectively remove one directions worth of members (usually roof or wall bracing). Then follow up with the RSA. Noting of course the results in terms of the forces are only valid for one direction of loading. Repeat for the other direction. Works best for tension only braces and structures with the same stiffness in both directions, but depending on your scenario may be totally inappropriate.

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