How to model elastic and perfectly plastic concrete & steel?

[mohsenrock]

Dear all,
I am about to model my 2D frame in opensees using elastic perfectly plastic material for steel and concrete.
By using concrete01 and putting the yielding and ultimate values of stress, my pushover analysis never stops and goes to infinity values for target deformation. Is there any suggestions for modeling the steel and concrete with this kind of behavior.

Which element is more accurate in this case? dispbased element or nonlinear forcebased element?

thanks in advance,

[gor]

Why are you using fibres then? You could use a lumped plasticity model with the constitutive model of the hinges equal to the elastic perfectly plastic behaviour that you want

[mohsenrock]

Because I am using my opensees model in order to validate the results that I have in my code, which is already lumped plasticity. Therefore, it is required to compare my results with a distributed plasticity one. By the way, how can I define a hinge with desired properties? do you have any example?