Geometric Nonlinearity

[RaminZ]

Dear friends,

I have started to verify the geometric transformation and considering a leaning column in OpenSees with SeismoStruct for P-Delta effects.

To start, I modeled a 2-dimensional 1-bay & 1-story steel moment frame using infrmFB elements in SeismoStruct and fiber sections and nonlinear beam-column elements in Opensees. There is not any mass or gravity load in these models, and I unchecked the geometric nonlinearity box in SeismoStruct.

After a PushOver analysis, the results are completely the same. However, when I check the geometric nonlinearity box, the model in seismostruct fails to converge. First of all, when we do not have any gravity loads, including geometric nonlinearity should not have any impacts on our model! It is true, isn't it? Moreover, I changed the number of integration points from 10 to 3 but nothing changed.

I would really appreciate if someone could help me.

Sincerely,
Ramin