Hoist preparation

Concrete"s great in compression, no problem with your load, but put it in tension, like carpenter was talking about, and you"ve got a problem that only rebar will solve. And then you"re going to need engineering help to design the concrete. If your ground under the concrete will support the load, you"re fine with just concrete.

Might be time to get a soils guy in there to determine your soil bearing capacity. 3000 psi concrete is commonly used. Times 144 (in/sq ft) is more than you"ll need.

Fitting one of these in an existing space will cost more for the remedial work to accomodate the hoist, but for a new construction we're talking some extra concrete, reinforcing bar, possibly some steel and some embed type anchors. We used to mount temporary material and personell hoists to structural slabs, they were not that big but did the job with a lot of weight applied. The details for these were engineered and provided to us. One large structural slab on top of well compacted load bearing soil, underneath the finished slab would certainly do the job here if I were to take a guess, it may be overkill but you know it's tied off to a boat anchor ! So much easier when doing new construction, just some additional cost, no demo needed. Again, I put my technical hat on here, must miss my old job ..... . NOT !!! LOL !

carpenter

I would want the manufacturer to provide an anchor detail, if a 5" slab calc's out, let them go on record stating it works based on an engineers calculation. To be quite frank, I'd not want to be wondering about something that is supporting that kind of weight. It should be designed according to the manufacturer. I would also think that something like a 2'-0" x 2'-0" x 1'-0" thick or similar column base footing with appropriate size anchors embedded in the footing would be necessary. This detail would not be a difficult task for an engineer to calculate what would safely displace the loads applied. Usually the footing for a column is below the bottom of a finished slab, they pour the slab over the footing, but make an isolation joint at the column line, cracks have tendencies to occur at the outside corners of these, I think that is what the isolation joint helps avoid. I can imagine the manufacturer must also have considered a customer who has an existing space with a concrete slab and is not building new, so they can sell the product that would bolt up to a slab, possibly using a larger baseplate, more fasteners, to displace it over a larger area, reducing the point loading. Again, don't mind me, I'm just thinkin aloud here !