Hi, Dear All,
I have a quick question regarding composite section (e.g. concrete deck on steel I-beam). How does STAAD Pro handle the composite section (beam element) under negative moment? Does it by default ignore the concrete portion when the composite section takes negative moment? Please help.
Thanks,
Dong
This is what it does for CODE AISC. There is a parameter called CMP which you can set to 0 (default), 1 or 2.
when set to 0 - beam is designed as non-composite
when set to 1 - beam is designed as composite if the concrete flange is in compression throughout. If anywhere along the span the flange is in tension, the beam is designed as non composite
when set to 2 - beam is designed as composite and any moments causing tension in the concrete flange is neglected from the design.
Hi, Dear Sye,
Thank you very much for the quick answer. What you said it's about the design calculation in STAAD Pro I believe. I also want to know how STAAD Pro handles the composite section bending stiffness in the FEM analysis. Does it always ignore concrete portion (cracked) when the beam element takes negative moment? Or the section property is also related to the CMP parameter?
Hi Dong : Yes I was purely answering from the design perspective and the CMP parameter is purely related to design. From the analysis point of view, the bending stiffness will be based on the composite section as long as there is connectivity between the plate mesh and the beam elements. The nature of moment in the slab would not have any bearing on that.
Answer Verified By: Dong Wang