Rigid story in 2D models

[foadEng]

Hi
I am doing a pushover analysis on 2D frames. I wanted to know if it is possible to make every story rigid or not?
I've used "elasticBeamColumn" command with very high value for moment of inertia to make beam elements rigid. But for column elements, I've used "nonlinearBeamColumn" command. Using this two commands, my model's period are different from the case when both beams and column are constructed using "nonlinearBeamColumn". But in latter, the analysis won't proceed properly!
I'll really appreciate any help!