FKX or Section 12 Cellular Deck

[Struct1206]

I have an existing building (circa 1960) with, what the plans call, "4 1/2" cellular steel floor + 2 1/2" conc." I'm trying to analyze the floor deck and framing for a new piece of equipment the tenant wants to install. Does anyone have any idea what this decking might be? It appears to be Section FKX or Section 12 from the 1980 Robertson ICBO report (these look like what they show on the drawings). It appears to be a non-composite roof or form deck with concrete. Also, how do you typically handle point loads on a deck like this? The proposed equipment I'm looking at is on wheels, so point loads it is.

 

[RPMG]

Sometimes, in existing buildings, it can be reasoned that the deck is being used in its intended purpose, and therefore doesn't require additional review. For instance, if people are running fork trucks on it without damaging it over 60 years, then a light piece of equipment isn't going to affect it.

Other times, the deck can be reinforced to take it out of the equation.

SDI does provide a procedure for running numbers. It has been put into guides by Vulcraft and Canam. However, it's awful and relies on transverse reinforcement to spread the load rib to rib. Basically, the procedure says that their slabs can't support any significant point loads unless the rebar is piled in it, which is empirically false. Also, all of those manufacturer's tables with the wire meshes, they assume that there is no slab negative moment strength because it cracks.