Unusual Floor Slab

[ntn94]

Has anyone ever seen or worked with a floor slab similar to this? It appears to be metal lath supporting some sort of concrete fill with a wire mesh, similar to stucco wall finishes. The second photo shows where a previously added metal deck and this original floor system meet. The reinforcement appears to have been cut and not re-connected/supported on the adjacent joist which is not ideal.

PS: Metal deck does not exist under the metal lath/concrete fill. Open web joists are ~24" oc.

If there are any references to this type of floor system, any insight would be greatly appreciated.

 

[Celt83]

Looks like a draped mesh slab, if I remember correctly it is designed so the mesh acts as a catenary between the joists and the concrete above is just for load distribution.

 

[phamENG]

Yep. Working on one now, in fact. My MO - leave it alone.

What do you need to do with this one?

 

[ntn94]

There are portions that are damaged which we'll need to replace with new concrete over metal deck but ultimately, they want to raise the floor a few inches by adding a concrete topping (~30psf of additional load). Unfortunately, the original gym live load is equal to the new/current live load for the new retail store taking over the space so I can't simply say the difference in load accounts for the addition. But given the joists are at 24" oc and draped mesh slabs can generally take quite a bit of load, I think it should be ok. Just need to look at the steel joists a bit closer.

 

[jerseyshore]

Definitely draped mesh. I've seen it in older NYC buildings.

Had to analyze one for a gym years ago. I am pretty sure one of the old WWF books had info on them. Like an old old book. Had it at my old office. Maybe someone can confirm.

Might be this one:

https://www.amazon.com/American-Welded-Fabric-Concrete-Reinforcement/dp/B000K6MGVA