Axial force of column section is very small. Why?

[tthdl]

Hello everyone,

I'm trying to do a pushover analysis on a 3 storty 3 bay 2D RC frame with fiber section.

The results of pushover is very strange.
1. The axial force in the bottom section of the column is very small only 12726.2N, but the nodal axial force at the same position is 235068N
2. I got larger axial force in the beam section than in the column sections.

The column end is all fixed, no rigidDiaphram and no equalDOF is post on the beam nodes.

5 elements were given for each column members and 6 elememts for each beam members.

the element type is dispBeamColumn.

Could anyone please tell me why I got so strange results? Thanks!

[fmk]

the fact that section axial force and element axial force is not consistent is a result of how the element force is calculated for a DISPLACEMENT based element" .. basically loop over all the gauss points in the element and combine the forces using the forces at the gauss points and the gauss point weights

https://www.youtube.com/watch?v=yk-1k2aF53E

[tthdl]

Thank you very much! I will change the element type and try again.