Bottom rebar in slab over steel deck - clear cover?
Bottom rebar in slab over steel deck - clear cover?
(OP)
I have a 6" total thickness slab over steel deck (4.5" concrete over 1.5" B deck) that has been designed for forklift loading. Following SDI's (Steel Deck Institute) guidelines, the deck is form-only and reinforcing has been provided to support the forklift loading.
The bottom rebar is intended to be in a low flute, with a little over 1" clear from deck to bar. The "d" depth of the bar is 4-1/2" from the top of the slab. Obviously this is my primary design concern - I want to maintain this effective depth.
At some locations, headed studs and spliced bottom bars result in the bars being pushed up against the side of the flutes (still maintaining the correct "d" depth and cover below), which means some of these bars no longer meet ACI clear cover of 3/4".
A couple of questions:
Is anybody aware of any guidance on bottom of deck clear cover for a slab on steel deck? ACI does not specifically address slabs on steel deck and SDI seemingly references ACI clear cover requirements, but they are clearly aimed at the clear cover to the top of the slab.
Are these bars still effective if they are up against (or very nearly up against) the side of a flute?
I'd appreciate any experience or code/standard references. I've reached out to SDI and am awaiting a response, but I thought I would ask here as well!
Thanks!
The bottom rebar is intended to be in a low flute, with a little over 1" clear from deck to bar. The "d" depth of the bar is 4-1/2" from the top of the slab. Obviously this is my primary design concern - I want to maintain this effective depth.
At some locations, headed studs and spliced bottom bars result in the bars being pushed up against the side of the flutes (still maintaining the correct "d" depth and cover below), which means some of these bars no longer meet ACI clear cover of 3/4".
A couple of questions:
Is anybody aware of any guidance on bottom of deck clear cover for a slab on steel deck? ACI does not specifically address slabs on steel deck and SDI seemingly references ACI clear cover requirements, but they are clearly aimed at the clear cover to the top of the slab.
Are these bars still effective if they are up against (or very nearly up against) the side of a flute?
I'd appreciate any experience or code/standard references. I've reached out to SDI and am awaiting a response, but I thought I would ask here as well!
Thanks!






RE: Bottom rebar in slab over steel deck - clear cover?
I would think only partially.....because they cannot develop on one side. You would also not be observing minimum cover requirements (as per the "corrosive environment" approach).
RE: Bottom rebar in slab over steel deck - clear cover?
Dik
RE: Bottom rebar in slab over steel deck - clear cover?
So proper ACI concrete cover is required period. Bars laying directly on/against flutes would NOT be OK.
I'll be approaching this by getting the bars shimmed off of the sides of the flutes while eating into the allowable 3/8" tolerance on effective depth and clear cover.
RE: Bottom rebar in slab over steel deck - clear cover?
Dik
RE: Bottom rebar in slab over steel deck - clear cover?
RE: Bottom rebar in slab over steel deck - clear cover?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.