Response Spectrum with non-linear elements

Question:

Hi,

We are modelling an elevated structure on shallow foundation, i.e. strip footings, with seismic analysis using response spectrum. The support from soil to the strip footing is modeled as compression only springs - simulating the soil compressibility and no tension resistance.

Yet, upon obtaining the result of response spectrum analysis, there is tension in the spring's reaction force.

1. Does MIDAS allow the use of non-linear elements in the analysis using response spectrum?
2. Is there a method to model the shallow foundation with compression only springs AND perform seismic analysis?

Thanks

Answer:Compression-only behavior is nonlinear effects which should be evaluated using nonlinear time-history analysis. Response spectrum analysis is a linear method which does not consider nonlinear aspects during formulation.

Regards,
DK Lee
Creation date: 5/7/2018 8:26 PM (dklee@midasit.com)      Updated: 5/8/2018 5:56 AM (dklee@midasit.com)