Composite steel beam with a different slab thickness on each side
Composite steel beam with a different slab thickness on each side
(OP)
Hi everyone,
When designing a steel beam that supports a steel deck on one side that has different properties than the one on the other side (as shown in the attached figure); what will be the effective thickness of the slab? Should we consider the minimum thickness? I appreciate any advice in this regard.
Thank you.
When designing a steel beam that supports a steel deck on one side that has different properties than the one on the other side (as shown in the attached figure); what will be the effective thickness of the slab? Should we consider the minimum thickness? I appreciate any advice in this regard.
Thank you.






RE: Composite steel beam with a different slab thickness on each side
Dik
RE: Composite steel beam with a different slab thickness on each side
BA
RE: Composite steel beam with a different slab thickness on each side
RE: Composite steel beam with a different slab thickness on each side
1) Don't bother with composite action.
2) Consider one sided composite action using only the lower side.
Based on the deck direction, I'm guessing this is a girder condition. That means that you're likely to have a steep curvature discontinuity over top of the beam and, because of the slap step, any rebar there won't be particularly effective. I think you'll be dealing with a location where you'll see a lot of slab cracking. To participate, that upper slab need to be shear connected to rest. I'm not loving the look of it in that respect.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Composite steel beam with a different slab thickness on each side
When I did the Cornwall Centre in Regina (a long time back) the difference between composite and non-composite construction was nearly 30c per square foot... first project I used single angle connections (and there were a kazillion of them)... In addition, deflection was greatly diminished... Used a TI58? programmable calculator for composite construction; it had little mag strips.
Dik
RE: Composite steel beam with a different slab thickness on each side
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Composite steel beam with a different slab thickness on each side
The way I solved this problem is by considering the (Effective Slab Thickness) = (Overall Depth of the Smaller Slab) - (Rib Height of the Larger Deck)
This satisfies the CSA S16-14 code requirement which defines the effective slab thickness as the "MINIMUM thickness of concrete measured from the top of the slab to the top of the steel deck".
RE: Composite steel beam with a different slab thickness on each side
"If two or more deck sections span in the same direction and have the same value of tc * f′c , the program uses the deck section with the smaller tc value."
RE: Composite steel beam with a different slab thickness on each side
RE: Composite steel beam with a different slab thickness on each side