Diamond Dowels for Reinforced Slab on Deck 1

[murphy89]

Hello, Here is the situation:
Level 2 in a warehouse will have forklifts roving around.

Floor system is: 6" total thickness, composite steel deck with concrete, reinforcing top and bottom both ways. Contractor wants to do a construction joint. I am going to direct them to place it in the middle third of the span between main beams, continue the rebar at least 1 development length through on each side.

The questions is, to transfer the shear should I call for a shear key or diamond dowels? Has anyone used diamond dowels in a slab on deck scenario?

Thanks!

 

[KootK]

How thick is this slab? Normally, I would get this done via shear friction or I wouldn't do it at all.

Composite deck tends to shear debond under the kind of concentrated loads often imposed by forklifts but I guess that's a separate discussion.

 

[murphy89]

deck is 1 1/2" and total thickness of system is 6".

I had read when designing it about the debonding between composite deck and concrete due to forklifts so have planned for that.

 

[XR250]

That seems kinda thin for forklift duty.

 

[dik]

Most deck suppliers do not recommend using deck with transient loads... you can use it for formwork. I've used diamond dowels (but not with deck) and they seem to work well. I've not heard of any problems with them.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[KootK]

The diamond dowels seem weird to me for this application. Usually one does that to allow for a measure of in plane movement on either side of the joint that, in this case, will already be restrained by the steel decking.

I had read when designing it about the debonding between composite deck and concrete due to forklifts so have planned for that.

Sure. I got burned on this once in the past by not having real reinforcing in the slab. The slab cracked to hell and back in hogging over the beams. As long as you've got some real top steel over the beams, you'll likely be spared that indignity.

 

[hokie66]

Diamond dowels make no sense in this application. You don’t want joint movement. And in such a thin slab, getting concrete under the plates would be problematic. Use regular deformed bars, placed centrally.

 

[JLNJ]

I second, or third, the "seems rather thin for roaming forktrucks". Shear capacity gets eaten up pretty quick under an 8 or 10 kip small-contact patch wheel load.

 

[GC_Hopi]

6" total thickness, composite steel deck with concrete, reinforcing top and bottom both ways

Seems a little tight for top and bottom both ways reinforcing especially when deck is 1 1/2" and total thickness of system is 6".