Concrete Integrity Question

[kyle@hcb]

Concrete Integrity Question // MaxJax

Greetings all. So I've decided to go with a Max Jax portable lift in my garage; ceilings are not tall enough for a full sized 2 post. Also unfortunately, I have a pole that separate the two spaces, so one of the lift posts will be installed right next to the pole. One or (possibly) two of the anchors will need to go through the concrete shown in the following pics. What do you guys think? Any concrete experts on here? I appreciate any/all help. Thanks! (garage is a standard 20x20)

 

[Nowater]

Is that pole a steel column? I cant tell from the picture.

 

[kyle@hcb]

Is that pole a steel column? I cant tell from the picture.

I'm not 100% sure. It was already covered when I moved in a few years ago.

 

[DougWil]

You really haven't given any info that could help determine anything.

How thick is your slab?
What is the reinforcement?
What is the load on the column?
How is the column attached to the slab?
Was the slab thickened at the column or have a footing underneath the slab?

Since you didn't build it you probably don't know any of the above.
So probably the best option is bolting down a 1/2" or thicker plate to spread the load out where the lift sits. Putting a sheet of reinforced rubber below the plate will help avoid stress concentrations.

 

[kyle@hcb]

You really haven't given any info that could help determine anything.

How thick is your slab?
What is the reinforcement?
What is the load on the column?
How is the column attached to the slab?
Was the slab thickened at the column or have a footing underneath the slab?

Since you didn't build it you probably don't know any of the above.
So probably the best option is bolting down a 1/2" or thicker plate to spread the load out where the lift sits. Putting a sheet of reinforced rubber below the plate will help avoid stress concentrations.

I appreciate the reply/suggestions! The slab is 6" thick. I don't have answers to your other questions.

 

[kyle@hcb]

Edited title to reflect the lift type.

 

[machsnell]

Re: Concrete Integrity Question // MaxJax

If you have a 6 inch slab I would think you would be fine. How do you know the thickness of slab?

It appears the slab is in good shape and not cracked.

It does appear that the cincrete around the column was parged after the original pour or recently? It doesnt appear to be flaking off and if your concrete wasnt solid it would have cracked off of one of the corners of the column. This assumes the.column indeed goes into the slab and doesnt rest on top of it.



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[kyle@hcb]

Thanks for the reply! The company that did the termite protection plan (part of the warranty when I bought the house in 2014), drilled into the concrete; they relayed that it was 6" thick. The concrete is in good shape with no cracks. Not sure when the concrete was parged. The house was built in 1988 and I haven't done anything to it since moving in (2014).

 

[KaiserJeep]

The columns I'm looking at are probably boxing around round steel posts, probably with drywall applied as a finishing touch. I see a drill and some other type of item attached to it. With a few of those columns in line, they are supporting a beam (also covered with drywall). The posts will be set in the concrete, with some type of footer supporting them at their base.

The concrete floor looks fine, and should hold up any lift you can fit in there.

 

[kyle@hcb]

Thanks for the reply!

 

[DCarr2]

I personally would put a steel plate under your proposed post to distribute the weight over a larger area.

 

[Daedalus]

Re: Concrete Integrity Question // MaxJax

Greetings all. So I've decided to go with a Max Jax portable lift in my garage; ceilings are not tall enough for a full sized 2 post. Also unfortunately, I have a pole that separate the two spaces, so one of the lift posts will be installed right next to the pole. One or (possibly) two of the anchors will need to go through the concrete shown in the following pics. What do you guys think? Any concrete experts on here? I appreciate any/all help. Thanks! (garage is a standard 20x20)

You have to figure out the interface between the post and the slab. If the slab is poured around the post then it represents an edge. Follow the lift and anchor manufacturers' rules on edge distance. Typically you need to maintain at least 6" between anchors and edges or control joints. If the slab is continuous, then I wouldn't worry about it.

I personally would put a steel plate under your proposed post to distribute the weight over a larger area.

What kind of psi loading would you expect to see under the maxjax post, and what psi loading should be the goal with this added plate? Hard to fathom a stress of even 30 psi as designed. (Try scaling up from a tire contact patch at 32psi).

Too many folks out there wasting time and money for no benefits. Worse, it could end up being a catastrophic improvement.

 

[kyle@hcb]

^Thanks! Of your potential scenarios, which is the most common? (continuous slab or slab around the post)?

 

[Strouty]

It looks like either they set the post in concrete before they installed the floor or they added the post after the floor was poured. Most likely the post is embedded deeper into the ground since it is a support. Either way, there is an "edge" in that area, but it is not a straight edge, it is circular and I would think (maybe rationalize) that it is stronger than a straight edge.

 

[Daedalus]

If there were no modifications done, and the structure is all part of the original design, a monolithic slab is the most likely scenario. Especially if the post is wood--that would pretty much prove a separate footer is not required (but would not prove what's actually there). I would pick out a bit of the drywall or whatever is on the post at the base, and see what the seam looks like. Horizontal seam means the slab is solid. Vertical seam means the slab was poured around the post.

If you can locate the lift and keep the minimum edge distance to the anchors, then it doesn't matter.

 

[Strouty]

If you look at the pictures, the concrete is not the same.

 

[Daedalus]

I see *something* is not the same. Don't know what. Is that 2 concrete pours? I don't see any sort of cut line or seam. Looks more like someone troweled some kind of compound over the slab near the column, perhaps when they were finishing it.

 

[Strouty]

The OP will have to answer this, but the area around the post looks raised and overlapped. If they had finished it at the same time it would look more like the floor.