Concrete thickness for Revolution lifts.
- Thread starter jaydoc1
- Start date
kcobean
Enthusiast
While it's just a WAG, I'd imagine any standard concrete thickness would do. The feet on the posts aren't too much smaller than the contact patch of your tires. If the lift weighs 800 lbs, you're only adding 200 lbs per corner over the weight of your car as it sits on the ground. Make sense?
PatentLaw
Enthusiast
Most concrete is good for 3500 psi. Take up the total weight of the posts and the heaviest vehicle and divide by the area of the posts. Normally, there is a factor of safety of at least 3, so multiply the previous number by three. This should be less than 3500 psi. This is only for slab on grade stuff and should tell you if the concrete would fail.
The weakest point is going to be the anchors that are used to bolt this thing down. They should use a Hilti Kwik Bolt II anchor or equivalent. The manufacturer MUST specify this. Take care installing these anchors. Critical stuff. Overturning.
Unless you have a very thin slab, it is doubtful that the load from the lift will punch through the slab. A woman wearing high heals has a higher pressure capability under her foot than the posts of the lift. It is not cracking from that, so you should be fine. Anchors my man....anchors.
The weakest point is going to be the anchors that are used to bolt this thing down. They should use a Hilti Kwik Bolt II anchor or equivalent. The manufacturer MUST specify this. Take care installing these anchors. Critical stuff. Overturning.
Unless you have a very thin slab, it is doubtful that the load from the lift will punch through the slab. A woman wearing high heals has a higher pressure capability under her foot than the posts of the lift. It is not cracking from that, so you should be fine. Anchors my man....anchors.
kcobean
Enthusiast
I'm going to build a platform for my car so that the car sits on the platform, and the platform has a single 1"x1" leg on the bottom of it. The Viper weighs just shy of 3500 lbs, so the 1"x1" post should hold without punching through. If not, I'm comin' after you!!!
OK, the reason I asked this question is that the Complete Hydraulic lift site states:
<font color="red"> Our lifts require a 4” thick 3,000 psi tensile strength concrete floor for installation. Heavy-Duty lifts may require a thicker floor (we advise 6” concrete for the CL 14,000 FP & FP AR). Our CL 8,000 CSP (Car Stacker Portable) lifts do not require floor anchors, although they can be anchored down if that’s what you prefer. </font>
So I just assumed the same would hold true for most lifts. Most sites also state their lifts don't require floor anchors but I'm thinking I would want them. Now I called my builder and he thinks the garage floor was 4" thick but he's not sure of the tensile strength (great builder, huh?). Our soil here is a very compactible, expansive clay type soil and most of the houses are buit on caisons (sp.) so I was just concerned that the weight of the car focused on the four posts might crack through but from what you're saying it sounds like I should be alright. Besides after looking at all the pictures of these lifts in peoples' garages I can't believe that my builder would have poured a floor in a house only 3 years old with a substandard thickness. Although he could have, I suppose.
<font color="red"> Our lifts require a 4” thick 3,000 psi tensile strength concrete floor for installation. Heavy-Duty lifts may require a thicker floor (we advise 6” concrete for the CL 14,000 FP & FP AR). Our CL 8,000 CSP (Car Stacker Portable) lifts do not require floor anchors, although they can be anchored down if that’s what you prefer. </font>
So I just assumed the same would hold true for most lifts. Most sites also state their lifts don't require floor anchors but I'm thinking I would want them. Now I called my builder and he thinks the garage floor was 4" thick but he's not sure of the tensile strength (great builder, huh?). Our soil here is a very compactible, expansive clay type soil and most of the houses are buit on caisons (sp.) so I was just concerned that the weight of the car focused on the four posts might crack through but from what you're saying it sounds like I should be alright. Besides after looking at all the pictures of these lifts in peoples' garages I can't believe that my builder would have poured a floor in a house only 3 years old with a substandard thickness. Although he could have, I suppose.
So is my thinking correct here?
Each post looks to be about 1' X 1' so that's 576 square inches total area.
The car is about 3500 pounds and the lift is about 1900 pounds = 5400 total pounds.
So 5400 pounds/576 square inches = 9.3 psi. Even multiplying by three that's still 27.9 psi.
Am I correct? So an average garage floor should easily support a lift and Viper.
Each post looks to be about 1' X 1' so that's 576 square inches total area.
The car is about 3500 pounds and the lift is about 1900 pounds = 5400 total pounds.
So 5400 pounds/576 square inches = 9.3 psi. Even multiplying by three that's still 27.9 psi.
Am I correct? So an average garage floor should easily support a lift and Viper.
Jay Herbert
Enthusiast
Don't forget to remove the area of the lag bolt holes
Just kidding. For what it's worth, I've had my Diesel truck up on my Revolution XLT lift, GVW 8800 lb's, it did not go through the concrete. In my discussions with the lift mfg's most said that pretty much any professionally poured slab poured with the soil properly compacted and concrete wire meshed or rebarred should be no issue. Of course, they'll never write it down for legal reasons.
All the compressive concrete testing I've done (strength of materials class in College) on concrete showed mixed mattered a lot for ultimate strength... 3000 psi seems to be pretty much the "ground floor"... with up to 7000 psi being considreed "conventional concrete"
"What is 3,000 pound concrete?
It is concrete that is strong enough to carry a compressive stress of 3,000 psi (20.7 MPa) at 28 days. Concrete may be specified at other strengths as well. Conventional concrete has strengths of 7,000 psi or less; concrete with strengths between 7,000 and 14,500 psi is considered high-strength concrete"
Found the above on this site's nice concrete FAQ:
Concrete FAQ
The tire contact patch illustration is really one of the better ones I've seen.
PatentLaw
Enthusiast
Ok, I agree with all of the above. Concrete gets stronger with age, significantly stronger. 3000 psi concrete is pretty much the base....yours will most likely test out at 3700 or higher.
If there is minimal support, you could have a problem, but in this instance I don't think so.
Not making a house call here doc, but I was ready to get the old calculator and dull pencil out and start cranking some numbers for you. Then it suddenly dawned on me, if you took a Pontiac Bonneville, loaded it up with 4 normal sized adult people, and drove it into your garage into the place that you are going to support this lift, you would have the same loading condition. Your floor would not crack, and neither will the lift when installed. 4000 lb car + 800 pounds of people over a 4 small contact pressure area. I think that this patient has been saved and that it will work.
Of course, I am not a Professional Engineer in your state (am in others), but I would not worry about it too much. It is really the anchor depth for overturning at the posts that is the concern here. Follow their guidelines and you will have more than enough capacity. Safety is important, I agree. Good luck with it.
If there is minimal support, you could have a problem, but in this instance I don't think so.
Not making a house call here doc, but I was ready to get the old calculator and dull pencil out and start cranking some numbers for you. Then it suddenly dawned on me, if you took a Pontiac Bonneville, loaded it up with 4 normal sized adult people, and drove it into your garage into the place that you are going to support this lift, you would have the same loading condition. Your floor would not crack, and neither will the lift when installed. 4000 lb car + 800 pounds of people over a 4 small contact pressure area. I think that this patient has been saved and that it will work.
Of course, I am not a Professional Engineer in your state (am in others), but I would not worry about it too much. It is really the anchor depth for overturning at the posts that is the concern here. Follow their guidelines and you will have more than enough capacity. Safety is important, I agree. Good luck with it.
Fred(DrivingSchool)Kinder
Enthusiast
BendPak Concrete requirements:
http://www.bendpak.com/custom_page.isg?ref=bpakconcretereq
http://www.bendpak.com/custom_page.isg?ref=bpakconcretereq
