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RE: Mezzanine floor slab without reinforcement

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I am aware of a concrete slab that was "reinforced" with polypropylene fibers that was a 26 ga 9/16" form deck. For all intents and purposes it was basically unreinforced. It fell onto my shoulders to try to make it work. First of all the form deck is not bonded well and will not act as tension reinforcement. Even SDI ignores any flexural contribution of the shrinkage steel.

In the end you need to run your calcs as an unreinforced concrete flexural element. I would assume it is a single span simply supported element. It will probably work. The only problem is the shrinkage cracks. You will need to knit them together. If you do not knit them together:
1.  You will not get aggregate interlock
2.  The slab will not cantilever.
3.  You will get differential curling and develop tripping hazards

I would suggest that you don't even try to start to epoxy inject the cracks unless you have at least 90 days of age. That still is not all of the shrinkage that you will get, but it will be a lot of it.

Watch the epoxy it will run all over the place, and if I recall you have an occupied space below.

Go ahead and live on the edge. You may also want to keep some cash, a disguise, and a ticket to a Caribbean Island in your drawer. .....Just in case.

Harold Sprague

From: DSmith7367(--nospam--at)
Reply-To: <seaint(--nospam--at)>
To: seaint(--nospam--at)
Subject: Mezzanine floor slab without reinforcement
Date: Fri, 16 Jul 2004 09:53:33 EDT

Regarding my previous post concerning a new supported floor installation, I
have an additional question.

Has anyone ever specified or is anyone aware of a concrete slab on metal
slabform (9/16 x 26 GA) that does not use some sort of wire or reinforcing bars?

We have a case where the contractor built a 3" overall depth concrete slab
on slabform with no reinforcing. The slab has cracked badly and I feel uneasy
telling the owner that it will carry his 100 PSF storage load.

Dave Smith

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