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CSI Software applies an elastic-perfectly-plastic stiffness force-deformation relationship throughout analysis procedures. During time-history analysis, when stiff elements undergo inelastic behavior, additional measures may need to be taken to capture nonlinear response. This condition may be realized, for example, when adjacent columns are expected to demonstrate comparable performance, but experience axial-force discrepancy. When initially-stiff columns are subjected to dynamic loading, inelastic cyclic bending will soften the elements through cracking and the ratcheting of yielding tensile rebar. Axial velocity and excessive c K K j damping contribution may then skew the results generated through default settings.
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