Vehicle Lift Anchorage Requirements SDC D

[Gene Kranz]

I am working on designing foundation requirements for a 10k, 12k & 20k capacity 2 post car lifts for a dealership in SDC D. S1 is .137 SDS .285. Anyone have experience designing required footing sizes for these types of lift. Current design is 6” slab with 2.9 WWR 6x6.

“Let’s work the problem people, let’s not make things worse by guessing”
- Gene Kranz

 

[GC_Hopi]

I saw someone build one of these and they went with a 6" slab. The lift manufacturer's will tout a 6" slab but there is no FOS in that and also they vanish if there is a failure. I would say check it as if the lift is a cantilever from your foundation put the appropriate idiot factor on the load (technicians can easily overload the lifts) and make sure the anchorage is robust (#1 point of failure from what I heard).

 

[XR250]

I know the ALI (American Lift Institute )loves this design but it sucks.
10k post reaction with moment on a 6" slab w/ WWF reinf?
Although, there are countless 10k lifts on 4" slabs without many failures.
Herd to determine the design loads as you don't know how off the posts the CG of the vehicle is.
On my 10k lift (Bendpak), each arm is rated at 2,500 lbs so I suppose you could figure out the worst case arm extension and calculate the moment based on that.
Also, you need to know if they are using the Mohawk style (in the pic above - no crossbar) or the normal style with a crossbar.
The crossbar will help with the side moment failure shown in the pic above.
I actually had that same lift in my previous garage - it was a beast.