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Re: Unreinforced concrete on metal pan deck.

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What impact does this have on the floor diaphragms?  Did you design the
lateral system based on rigid diaphragm analysis? The problem may be much
more involved than just cracked surfaces.

I find it odd that the only options you are listing are in your purview.
The contractor owns the problem and the cost of mitigation, IMHO.  How about
the option of "tear it out and build it per the plans and specifications".
(Sorry, but I get fed up with the constant "OH we did something different on
our own initiative, none of it worked, and now it is your job to make
everything all better").  The heavens will fall if the contractor actually
had to live with the results of their own choices.  They did not want your
input when they decided to substitute a cheaper inferior product to maximize
their $$$, but you have to come up with some miracle fix to save them from
the cost of fixing the problem.

To mitigate the problem you may need to look at providing a quality topping
slab, SIKA products come to mind. But then the structure needs to be
verified for the additional dead load, both vertically and laterally.  Sand
blast all the surfaces, fill all the cracks, provide a bonding agent and a
quality topping slab.

Alternatively, specify steel cross bracing under the existing floors for
diaphragm capacity and just enough surface treatment to mitigate the cracked
un-even floor surfaces.  The assumed shear distribution / diaphragm behavior
will have to be consistent or the lateral system revisited.

There are no cheap easy fixes for total floor system failure

Paul Feather PE, SE
pfeather(--nospam--at)SE-Solutions.net
www.SE-Solutions.net
----- Original Message -----
From: "Timothy P. Spengler" <timothyps(--nospam--at)cleanpak.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Friday, September 13, 2002 3:33 PM
Subject: Unreinforced concrete on metal pan deck.


> I've got a (3) story, Class A office building with a 70' x 100' footprint
that has your typical concrete over metal pan deck floor construction.
(Seismic Zone 3 construction) The contractor requested, and was granted, a
fiber mesh substitute in lieu of the WWF.  He then proceeded to use an
incorrect, lower grade type of fiber mesh and now the concrete deck is
cracking all to hell.  The building official wants me to sign off on this
fiasco so I'm stuck with finding either 1) a mitigation solution. or  2) a
way of justifying "semi-unreinforced" concrete on metal pan deck.
>
> I've got Verco and the fibre mesh company trying to help me out on this
one and I'm expecting some reports from them shortly.  Anybody out there
have any additional thoughts, ideas of opinions?
>
> Thanks.
>
>
>
> Tim Spengler PE,SE
>
>
>
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