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Re: Concrete Cover Over WF Beam

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It is going to be sealed concrete, no other finish.

I was thinking I could put a 3/8" cover plate along the entire length of the top flange of the beam and just pour the concrete up to each side of the cover plate . The top of the cover plate would then be exposed when looking from the floor level, which is alright for this application. But, there will be a shrinkage crack that will form on each side of the cover plate that would need to be closed with joint filler.

Any other ideas?

WH

On Fri, Aug 21, 2009 at 11:11 AM, David Topete <d.topete73(--nospam--at)gmail.com> wrote:
Expect the 3/8" concrete to spall/crack/crumble.  No way around that.  What's gonna be the finish flooring material?  I'd say leave that strip bare during the placement of the topping, and come back with a non-shrink grout to fill above the WF.  But, others may have a better/simpler idea...


On Fri, Aug 21, 2009 at 6:49 AM, Bill Polhemus <bill(--nospam--at)polhemus.cc> wrote:
William Haynes wrote:
I have a case that is very similar to the following detail. I am only going to have 3/8" of concrete cover over the top of the WF beam.

Does any preparation to the beam typically done (sandblasting, applying epoxy) in order to insure the bond of the concrete to the top flange of the beam? This cover is not structural, is there a minimum cover recommended?

http://www.kerkstra.com/Hollowcore%20Details%2012%20-%2007/2312-1.pdf


Will Haynes
Remember that "cover" is specifically for protection of steel reinforcement against the elements. Unless you are going to add shear transfer studs (e.g.) to the top of the beam, you cannot expect a predictable amount of "bond" between the concrete and the steel so it doesn't matter if you "prepare" the surface or not. I'm not aware of anything other than studs, angles, etc., welded to the top flange of the beam that would provide a predictable shear transfer.

So the short answer is "whatever is practical." Make sure you don't have a situation where cracks due to incompatible displacements result; otherwise, I don't know that there are any rules about cover.

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David Topete, SE