temperature reinforcement

[McGill10]

Temperature reinforcement in Composite metal deck slab.

1. Do you use reinforcement as recommended on vulcraft steel deck manual(eg 6x6-W2.1x2.1)for composite deck or use more higher than that in typical situation.
2. Any experience on having cracks on composite metal deck slab after concrete pour ?-
First thing comes in mind is shrinkage cracks but typical reinforcement per vulcraft should cover that one. As structure has not received the full service load yet - I don't assume as serviceabilty/deflection failure. What would be the most common cause of cracks ?. would appreciate if anyone want to share the experience and thoughts.

 

[ILstructural]

I generally use the WWR recommended by Vulcraft for cracking, but it is somewhat sensitive to the contractor's QC and finishing techniques. It can easily get stepped on and end up in the middle of the slab.

It somewhat depends on you floor finish. Carpet and VCT can tolerate quite a bit of cracking. Terrazzo, not so much. Concrete will crack and educating the owner will go a long way towards heading off future problems.

 

[TXStructural]

Yes, we always used at least minimums.
Whether WWR, or #3 or #4 bars, reinforcement is required to be supported adequately, as required by ACI 318 and CRSI MSP.

Also for serviceability, you need to consider bars across stiffer members, such as girders, to restrain cracking across these members. Use 1 or 2 corner bars across each interior/reentrant corner, extending one development length on each side of the expected crack (we used #4 bars 4'-0" diagonal each corner.) Without both of these, you may have problems.