Re: concrete drop panels

Just to clarify, I put the soffit of the drop below the soffit of the slab by a measurement of atleast 25% of the slab thickness where the drop ends at its perimeter. (not 25% of slab + drop). I use that as a minimum anyway. My earlier message may have sounded as though it confused width and depth. I usually use drop panels that are fairly deep and fairly wide to control deflections....(it's the old Welton Beckett method), which I think pt has made obsolete....sorry for the earlier confusion if any...
> ----- Original Message -----
> From: "refugio rochin" <fugeeo@gmail.com>
> To: seaint@seaint.org
> Subject: concrete drop panels
> Date: Tue, 9 Oct 2007 09:54:18 -0400
>
>
> Thanks bye the way for all of the 8" columns input. Not sure if I
> learned anything, but interesting to see people's different input...
> I am usually concerned with that issue on residential buildings. lots
> of architects like skinny columns ! concrete is much cheaper than
> steel tubes... I think I might look at the column with a P-Delta load
> plus the P, and see if it can take it. Also to look at buckling...
>
> Concrete Drop Panels
>
> ACI has a drop panel requirement:
>
> Section 13.3.7.2 - Projection of drop panel below the slab shall be at
> least one-quarter the slab thickness beyond the drop.
> ???
> This wording has confused me. I think however, that it means the drop
> panel, to be considered a drop panel, shall be at least a 1/4 of the
> slab thickness, so if I have an 8" slab, then the drop panel shall be
> at least 2", giving an overall depth to the panel of 10" which
> includes the slab... no???
>
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Bart Needham, SE
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