Concrete01 for dynamic analysis

[ningxz]

Hi everybody.
there is a question. I use concrete01 and steel02 material to simulate a two stroy RC frame, the dynamic analysis result reveal that the axis force of the first floor column is compression but the y-direction displacement in the first floor is positive.
is there anybody come across the same question?

[fmk]

what element are you using?

[ningxz]

fmk wrote:
> what element are you using?
nonlinear beam column element. I think maybe the change of neutral axis during the whole analysis cause the element centerline longer