Foundation / Slab For Vehicle Lifts

[BSVBD]

I have information/data/cut-sheets from (2) competitor suppliers of 2-post vehicle lifts / hoists with capacities of 10 & 12K.

Both suppliers recommend only a 4" concrete slab. When asked about a moment at the base, a rep told me that the anchor bolt layout disperses the moment. How do these slabs NOT fail? What am i missing?

Myself and a colleague both come with 12" of each other in preliminary design in the neighborhood of requiring a 6'x8' footing.

One supplier said, "We've been selling them for years without a problem!"

 

[WARose]

I'd check what their assumptions are (in particular their assumed edge distance and subgrade modulus), and see if you agree with them.

 

[KootK]

Not so bad away from the edges. Link. Obviously the anchor bolt spreading business is layperson clap trap.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Brad805]

We ran into this recently too when repairing an old structure from the 80's. The lifts had been upgraded, so we re-installed them after the slab repairs were complete. Point loads aside, I thought the two post base connection detail was very light.