Outside concrete pad?

[glmf]

I am in the process of installing a 2 post car lift on its own concrete pad, just outside my garage. The garage isn't big or high enough to support the lift. So I currently work on my vehicles on a dirt driveway. A pad with full height lift will be a huge step up!
My plan is to build a I beam frame that the lift actually bolts to, and fill the interior of the frame with concrete. I already have the I beam so no cost is incurred there.
I am worried about corrosion on the steel. Can anyone offer any advice?

 

[Cyberbear]

Not knowing where you live or what size I-beam you will be using, you may want to consider having it galvanized before pouring the stabilizing concrete.

 

[wssix99]

My plan is to build a I beam frame that the lift actually bolts to, and fill the interior of the frame with concrete. I already have the I beam so no cost is incurred there.

Assuming that you design the I-beam frame appropriately, you'd need at least three beams to form an H, with moment-resisting welds. (The concrete won't give you any effective strength if you pour it around the I-beam. So, you either need the I-beam frame to provide stability for the whole system, or not use it at all.)

You'd probably be able to do everything for less money if you just pour the minimum pad required by the manufacturer. (This will be stronger than a single beam embedded in concrete.)

For something outside, I'd do a flat pad, 6" thick, 4000 PSI concrete, with a 1/2" rebar grid spaced at 6" suspended in the center of the slab. (This will give you a very durable slab that should not crack out in the weather.)

 

[glmf]

I have the I beam already, lots of it! And I live in Maine, so I know this will move with the frost.
Making the frame strong enough is a non issue. I have fabricated/welded for a living for alot of years.
I guess what I am asking is how to protect the steel from the concrete? Is there something I can coat it with, maybe epoxy paint to prevent corrosion? The I beams will essentially be the permanent forms for the concrete. The center spans will be totally in the concrete except for the top of the top flange.
Thanks for any help with this

 

[Rookie2]

I think combining the two will lead to cracking concrete. One or the other. Maybe consult an engineer.

build your frame and burry it below the frost line. Concrete will cause a deeper freeze if you clear the snow. use the concrete as a drive thru only (pad) . thats all i got ! good luck !

Spray the frame with plastic bed liner ! you owe me $1.00

 

[wssix99]

The concrete will crack and pull away from the steel. The OP would need to put in the rebar grid and weld it to the steel to keep the concrete in place. (Or use welded shear studs, like they do on steel/concrete bridges.)

The cracks will still happen - the concrete just won't pull completely away.
Water will run down between the steel and concrete.

Making the frame strong enough is a non issue.

Do you have a design for the shape of the frame?

I guess what I am asking is how to protect the steel from the concrete? Is there something I can coat it with, maybe epoxy paint to prevent corrosion?

The same epoxy steel suppliers coat rebar with or galvanizing would be the most durable. Both of these are very expensive options. (I recently paid several hundred dollars just to get a few pounds of steel galvanized.)

You will still need the concrete and rebar - the same material as if you did a monolithic slab. Putting the steel in to the equation adds a lot of complexity and cost. I'm not sure what you'd gain by using it. (It could be stronger, if done right, but a monolithic slab is plenty strong as-is.)

 

[bcradio]

Pour giant footers

 

[glmf]

As for the design of the frame it's basically a box the size of the pad, with two more beams across the middle. The two across the middle are placed at the ends of the feet for the lift. All joints in the beams are welded. Flanges welded together, webs joined with welded angle iron.
But you guys almost have me convinced to not use the beam and save it for another job!
The lift is an old Challenger Vbm model 20000, 7k capacity. So a 6" thick, 4000lb concrete, with 1/2" rebar, 6" grid suspended in the middle of the pour will be strong enough for the lift and the heaving that will occur during the harsh Maine winters?
You guys are right, the pad just described will be cheaper and easier than the steel frame idea. Pad Must have to be wider than the lift so the lags are not on the edge of the pad?
Thanks for the comments guys, please keep them coming

 

[maiyingxi]

you may want to consider having it galvanized before pouring the stabilizing concrete.

 

[wssix99]

But you guys almost have me convinced to not use the beam and save it for another job!

I think that's good. You can always donate the steel to needy Garage Journal members!

So a 6" thick, 4000lb concrete, with 1/2" rebar, 6" grid suspended in the middle of the pour will be strong enough for the lift and the heaving that will occur during the harsh Maine winters?

I would think so. This spec is overkill for what the lift needs. (The lift only needs 4" and no rebar.) This is a lot of reinforcing, but is what one would use if one wanted to over-reinforce the slab so that control joints aren't required. (So it should be plenty capable of handling winters, IF you put it on a proper, compacted stone base. - Compacted with a vibrating compactor.) If you want a tank, this spec should be it.

If you want to economize some more on the slab, there is room to do so and I'm happy to help. Depending on the size of your slab, all that reinforcing might be getting expensive. (Reducing the thickness of the slab, adding control joints strategically, etc. will lessen the need for rebar.)

 

[glmf]

The ground this sits on is another problem. My lot has ledge popping out of the ground everywhere. Not sure how much depth I have to play with and won't know until I do the site work. Should start in the next 3-4 weeks.
Can you please explain the properly compacted stone base in a little more detail. Thanks very much for your time.

 

[James-W]

I don't mean to be negative about this, but since you live in Maine, the lift will be out in the cold and snow and using it will be difficult, if not impossible, during the Winter months. Isn't having the lift outdoors sort of self defeating? Having a lift to work on vehicles is a great idea, but if you can't use it because of bad weather, that's kind of a problem.

Maybe you should just build a high ramp (with a wide opening in the middle) from concrete to drive the vehicle on when you want to work on it. I know it wouldn't be as nice or as practical as having a lift would be, but on the other hand the concrete doesn't care about sitting outside and it certainly wouldn't rust.

 

[Bondo]

The ground this sits on is another problem. My lot has ledge popping out of the ground everywhere. Not sure how much depth I have to play with and won't know until I do the site work. Should start in the next 3-4 weeks.
Can you please explain the properly compacted stone base in a little more detail. Thanks very much for your time.

Ayuh,.... That ledge will probably be a Plus,.....

Concrete settin' on bedrock don't shift, at all with frost,....

It takes water for frost heaves,.... that's usually clay/ dirt,...

Solid rock don't hold water,....
Just make sure to drain any fill areas,...

For compactin' fill,....
If yer usin' bank run gravel, ya gotta go in lifts as thick as the larger rocks,...
Usin' graded stone fill, 6" lifts, 'n compactin' is SoP,...

If yer fill hole is in clay, try to make that hole self-drainin', before ya fill it with stone,...
Less water, fewer frost heaves,...

'n, steel, 'n concrete play quite well together,...
uncoated rebar has been used for 100 years,...

 

[Bondo]

I have the I beam already, lots of it! And I live in Maine, so I know this will move with the frost.
Making the frame strong enough is a non issue. I have fabricated/welded for a living for alot of years.
I guess what I am asking is how to protect the steel from the concrete? Is there something I can coat it with, maybe epoxy paint to prevent corrosion? The I beams will essentially be the permanent forms for the concrete. The center spans will be totally in the concrete except for the top of the top flange.
Thanks for any help with this

Where about's,..??

I grew up in Milford, 'n still got the family lodge at Chemo pond,...

 

[glmf]

James, valid point. But I work on a dirt pad now, outside and your right it ***** in the winter. I was spoiled many years ago with the use of a lift. Having it outside will present more maintenance on the lift that I am willing to do. It's kind of a hobby for me, the work that I want to do. So if the weather is bad, the work can wait.

 

[glmf]

Sanford area, southern corner of the state.

 

[Bondo]

Ayuh,.... North Mass,.....

 

[James-W]

James, valid point. But I work on a dirt pad now, outside and your right it ***** in the winter. I was spoiled many years ago with the use of a lift. Having it outside will present more maintenance on the lift that I am willing to do. It's kind of a hobby for me, the work that I want to do. So if the weather is bad, the work can wait.

Would it be possible to make the concrete pad as large as you would like a workshop to be? My thinking is that at some point in the future, you could build walls and roof around the lift and the floor would already be there. You would then have an enclosed work shop with the lift and at some point you can add heat for the Winter months. It's just a thought, but it may be something you might want to consider.

 

[wssix99]

Having it outside will present more maintenance on the lift that I am willing to do.

You might have some covers made for the posts or even wrap them up with heat-shrink wrap, like folks use on boats for the winter.

The ground this sits on is another problem. My lot has ledge popping out of the ground everywhere. Not sure how much depth I have to play with and won't know until I do the site work. Should start in the next 3-4 weeks.

Can you post a picture?

Can you please explain the properly compacted stone base in a little more detail. Thanks very much for your time.

The gravel serves two purposes: drainage and distribution of the load on the dirt. For example, if you have a 4" pad, adding 4" of gravel underneath will cut the pressure on the dirt below by a fourth.

In order for the pad to not move around and crack, you need the gravel compacted so it doesn't "settle." In order to compact sand, sandy soils, or gravel, you have to vibrate it. (Clays are different and get compacted with pressure.)

So, you'll need to get a... ********. You can also rent them. Here's what they look like: (so you can go out and get the right type of "********")

BTW - You can also call it a "Vibratory Compactor" if you are in mixed company and don't want to be misunderstood about what kind of machinery you are getting in to.