Concrete Between Steel Beams
Concrete Between Steel Beams
(OP)
I am investigating a 1-story structure that has 3 bays with (3) W12x22 beams runing 250" long 6'O.C.. 12" thick concrete is located BETWEEN the beams. When I analyze the steel, it is insufficient to support the concrete as a dead load + live loads and I believe that the concrete is actually working as a beam (self sufficient) in the long direction.
Can anybody offer any advice as to how I would make this determination? I am trying to show that additional dead load could be hung from the underside of the steel beams but it is not possible if the beams are supporting the dead load of the concrete placed between them.
THANK YOU for any help that could be provided...
Can anybody offer any advice as to how I would make this determination? I am trying to show that additional dead load could be hung from the underside of the steel beams but it is not possible if the beams are supporting the dead load of the concrete placed between them.
THANK YOU for any help that could be provided...






RE: Concrete Between Steel Beams
DaveAtkins
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
Thanks again
RE: Concrete Between Steel Beams
DaveAtkins
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
Do you know anything about the local history of the building - what it was used for? Any record or skinny of why this construction type was used? Machinery support?
Any indication of burn marks / discoloration on the exposed side of the steel beams that might indicate rebar being welded to the beam?
Mike McCann
McCann Engineering
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
In that the side of the two outside beams can be observed and measured, I would have to assume the dimensions measured fit that of a 12X22.
Mike McCann
McCann Engineering
RE: Concrete Between Steel Beams
I guess the question boils down to are the 2 elements(concrete and steel) working alone or in composition to some extent. Or that the steel is "doing all the work" which is what I am trying to prove is not the case.
Thanks all for your interest and response.
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
No deflection measurements were taken. I guess I could work backward if I measured deflection and determine how much load can be applied to the steel beam.
RE: Concrete Between Steel Beams
I think the deflection would only tell if the structure acts compositely for live load.
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
This is probably an obvious observation to all, but I thought I'd better mention it anyway...
If you do jack the beam, I would suggest jacking, or loading the beam in the upward direction, not down. The beam Will have more capacity in this direction, and be less likely to be distressed by the test.
Mike McCann
McCann Engineering
RE: Concrete Between Steel Beams
I thought about that after I posted, and even if it were cambered for the slab weight and settled down to horizontal currently, then the ultimate strength of the floor is the same but the total deflection would be different. I think he needs to find out if there is any reinforcing in the concrete and look into the strains of the system to make a decision on capacity. Shored or unshored, I think you have the same ultimate capacity if the strains permit.
Serviceability issues need a look into current deflection.
RE: Concrete Between Steel Beams
I also am not sure how I feel about forcing new deflection in the downwards direction without first knowing more about what is going on.
RE: Concrete Between Steel Beams
RE: Concrete Between Steel Beams
How long have you planned to live past 59? Then again, if you are bored and single, maybe the college life... Let's not go there.
Mike McCann
McCann Engineering