unusual bending moment diagram by sap2000 1

[Muhsin Abu Ali]

HI
I m getting unusual bending moment diagram for a floor system especially for primary member.
images are attached.
Need help from seasoned ppl!

 

[DaveAtkins]

I have never used SAP2000, but here are my observations:
* It appears you have a simple span with pinned ends, so you should not be getting this type of moment diagram, UNLESS
* You are getting an envelope moment diagram which is showing multiple load cases on the same diagram.

DaveAtkins

 

[le99]

How the beam was modeled, how it is loaded, how about shear diagram???

 

[JoshPlumSE]

I've seen moment diagrams like this before. Usually, it's for beams that are connected to plate elements or a diaphragm with out of plane stiffness.... meaning that the beam is pretty flexible, but the plate / diaphragm is stiff enough that it's stiff enough to take most of the bending.