Axial force in beam & M-Phi for zerolength and forcebeam

[nithinvl]

I have two queries :
1. I modeled an 2D RC frame using forcebeam columns and have done the pushover analysis. I have used equalDOF for each floor. In the pushover results, I find high axial forces in the beams. When I remove the equalDOF command, the axial forces become small.
Same frame i modeled using elastic beam-column elements with equalDOF command and i got zero axial forces in the beams. But for this frame with elastic beam-column elements, i get some axial forces in the beams when i remove the equalDOF command.
Can u please explain why this is happening ?

2. I have done moment-curvature analysis for an RC section modeled using zerolength section element and force-beam-column element. But the moment-curvature curve from both the cases are different. Why ?

Thanks
Nithin.