Baseshear-displacement curve not degrade while all Nonlinear link yield

[nuttaphon.B]

Hi

I'm running Static time history analysis on steel frame (pin base with Nonlinear link at all Beam-column joints) by applied lateral and to monitoring Base shear-displacement curve in global response.

I found that all of my nonlinear link was yielded but the structure capacity curve did not degrade and still linearly increase although I apply very large lateral displacement.

Could you suggest the possible error I made on my model?

Thanks

[seismosoft]

It depends on the nonlinear rules that you have applied in your model, the deformation demand on these links and the way that a possible yield in the link affects the global structural response.
One possible thing that crossed my mind is that the deformation-based performance criteria (when they employ the Notify directive) they inform about the attainment of a certain deformation, but they do not affect the behavior of the element.
Seismosoft Support