Concrete & setback requirements for 4 post lift

[sierradmax]

I'm trying to decide the best, suitable location for a 4 post lift to be used as a storage lift. I've narrowed it down to the Atlas 8000 EXT because of height clearance, price, & Greg Smith dealer is 1 hr. away.

I cannot find any info as to concrete requirements & setbacks. Ideally, I would like to place the lift in such a way where one of the posts would be up against a precast bulkhead (I have basement access through the garage via a set of precast stairs).

One would think that concrete & setback requirements are less for a 4 post than a 2 post. Any ideas?

 

[crook038]

This is from page 23 of the installation manual:

7.2 Installation Surface

The lift does not require to be anchored to floor. But, despite if it is anchored
or not, a level floor is suggested. Any major slope change will affect the level
lifting performance. If a floor is of questionable slope (more than 3 degrees),
considering to pour the new concrete slab. The new concrete slab must be
adequately cured by at least 21 days.

If the lift is chosen to be anchored to floor, the concrete slab should have the compression strength of at least 3000 PSI
and the minimum thickness 6” with an extension of at least 5’ from anchoring point.

http://cdn.gregsmithequipment.com/d...57.1670126414.1524149112-847305903.1524149112

Sean

 

[firebirdparts]

That all seems very reasonable (and translated from Chinese), although you can see that the 5' from anchoring point is a pretty heavy limitation. The 5' is not required for the lift itself. It's just required so that you don't crack the concrete with an optional anchor. If I was buying a 4 post lift, I would probably be planning to stick it in a garage close to the wall, and I would end up ignoring that if I bought one. It is possible in fact they meant to say 5 inches. If they don't supply the anchors, you might want to go by the anchor manufacturer instead if you anchor it.

" As a rule of thumb, the expansion anchor industry has established a minimum standard of ten (10) anchor diameters for spacing between anchors and five (5) anchor diameters from an unsupported edge. " YMMV

The thing about the 4 post lift is that the load is 100% compression, and the floor is going to hold it with only slightly more strain compared to how it holds a car on 4 tires. You wouldn't expect severe requirements.

 

[pbon]

The only concern is if a post is on the edge a pad and the pad cracked there and broke, the then 3 legged lift would be unstable and could tilt and drop a car. The loaded lift, if not on the edge of a slab is much like parking an 8000-10,000 lb truck. The trucks 4 tires have contact patches probably smaller than the post feet.