Today could have ended up MUCH worse

[CBradio]

At work today I put a toyota tundra on the lift to do a flat repair on the rear. Lifted the vehicle up ~6 inches, took the tire off, plugged hole, balanced, etc. As I'm putting the wheel back on vehicle, I hear a SNAP like thunder and another tech screaming F**K F**K HURRY THE F**K UP. I rush to get the wheel back on and quickly lower the truck down. I get up and the other tech says that I shouldnt get excited, but the concrete started to crack.

Anyways, I back the truck out and get a look at the base of the lift. THE WHOLE LIFT CAME OUT OF THE CONCRETE!. I dont know if the bolts broke or what happened, but the cement definately doesnt look right. Looking back, I thank my lucky stars that I didnt lift the truck up to chest height.

 

[A_Pmech]

This is (one of the reasons) why I won't use those damned things.

Glad you're OK!

 

[mrb]

This is why I won't use those damned things.

Glad you're OK!

yep. i feel they should have a footing under each post with J bolts (all engineered) not the redheads into a couple inches of godknowswhatpsi slab that is deemed acceptable.

 

[robertlynk]

I'll bet moisture under ground and reaction with soil weakened concrete

 

[CBradio]

Thanks AP.

In that first picture (sorry for the bad quality) the white area is the edge of the crack. The blue post started tilting and lifted that whole piece of concrete up about 4 or 5 inches. The second picture is the ground level shot of the concrete underneath. Its very brittle and 'sandy'

 

[A_Pmech]

yep. i feel they should have a footing under each post with J bolts (all engineered) not the redheads into a couple inches of godknowswhatpsi slab that is deemed acceptable.

Amen!

I've always been COMPLETELY astonished at the lack of engineered foundation drawings for automotive lifts. Hell, my lathe came with a set of foundation drawings!

As far as the blurry pics, I would have been shaking too!

 

[ZRX61]

Amen!

I've always been COMPLETELY astonished at the lack of engineered foundation drawings for automotive lifts.

Yup, always bothered me too.

 

[willymakeit]

Thanks AP.

In that first picture (sorry for the bad quality) the white area is the edge of the crack. The blue post started tilting and lifted that whole piece of concrete up about 4 or 5 inches. The second picture is the ground level shot of the concrete underneath. Its very brittle and 'sandy'

Bad concrete , wrong thickness, and probaly no steel and footing underneath. Glad your ok.

 

[Nighttrain]

This made me think how everyone is getting these lifts and installing them in their garages without adding additional re-enforcement. Believe me I want a lift but am now thinking that I should have had had designed the floor better. When I pour the slab I just had no idea where to put the lift.

I imagine this is a two post lift? The side forces are what matters and not just the weight of the lift and car on it. Glad your safe and thanks for posting.

 

[NUTTSGT]

You're right, that coould have been way worse. Play the lottery tonight.

 

[Shadowdog500]

Do you have any idea of what the floor thickness, PSI, and reinforcement on the floor, or the weight in the back of that truck. Assymetric lifts also scare me with heavy loads because of this type of thing.

Most lift manufacturers do give a minimum spec for thickness, Here is the one for Mohawk which is pretty good detail: http://www.mohawklifts.com/library/manuals/Slab_Require_Recommend_11_07.pdf

When I was putting my building up I specifically referenced Mohawk's slab requirements and made sure I exceeded them by a big margin. I also discussed putting J-hooks into the concrete with the local Mohawk dealer/installer and he strongly advised against it, because most of the time they are not installed exactly and dont line up with the holes in the bottom of the lift. I also queeried about seams in the concrete and was told 1' from the lift is the minimum that he felt was safe(I noticed your seam was closer).

It ***** that your concrete failed, but I am glad to see that the anchors held onto the concrete so well. That is the one thing I was worried about.

Chris

 

[tdkkart]

If you look back through my posts you'll find me frequently saying "I do not like/trust 2 post hoists." This is just one of the reasons why. There's just too much leverage force, and as the lift goes higher is gets worse and worse. If the truck had been lifted higher it probably would have blown completely out. Look a the concrete in the 2nd picture, it's complete ****, and you can bet it's the same in the entire shop. If whoever installed the lift had known what they were looking at, they would have recognized the **** concrete when they drilled the holes.

 

[bluesman2a]

This is (one of the reasons) why I won't use those damned things.

yep. i feel they should have a footing under each post with J bolts (all engineered) not the redheads into a couple inches of godknowswhatpsi slab that is deemed acceptable.

And this would be why I had my concrete contractor pull out and entire slab of "questionable" concrete. It's also why each post has a 3'X3'X2' caisson with 4000PSI commercial concrete under it. When the guys from Rotary came out to drill my junk, I doubled the depth of the supplied wedge anchors, used exopy too, and the guy kept saying, "You don't NEED all this... This is some of the hardest damn concrete I've ever drilled!"

I know, but it makes me feel better when I'm under a big truck!

Glad to hear the OP is OK.

 

[ScaldedDog]

I ended up getting an in-ground 2-post lift, and photos like that make me remember why. Glad no one was hurt!

Mark

 

[Licensed to kill]

Your right, it could have been MUCH worse http://www.break.com/index/truck-service-fail Lifts always make me nervous. Glad your OK.

 

[R6 Racer]

You're right, that coould have been way worse. Play the lottery tonight.

+1
Play the lotto & ask the wife/gf for that something extra she always "no" to!
Luck always happens in 3's.

Steve

 

[CBradio]

The only part that really worries me, is that I've put bigger vehicles on these kinds of lifts. And there are 10 bays in the shop, 7 have lifts identical to this one. If this one is like that, who's to say all the bays arent like that. I think this in one of those issues I'll bring up to corporate.

 

[haugy]

This made me think how everyone is getting these lifts and installing them in their garages without adding additional re-enforcement. Believe me I want a lift but am now thinking that I should have had had designed the floor better. When I pour the slab I just had no idea where to put the lift.

I was in the same boat. I knew I'd be putting in a lift, but didn't know where. So I got 6" 4000psi concrete with rebar all throughout the shop. That should hold up. I hope.

 

[Brad54]

I think I just decided on a 4-post lift!

-Brad

 

[ZRX61]

I also discussed putting J-hooks into the concrete with the local Mohawk dealer/installer and he strongly advised against it, because most of the time they are not installed exactly and dont line up with the holes in the bottom of the lift.
Chris

Solution to that issue is a plywood template of the bottom plate with the holes drilled in it to hold the bolts in place while the concrete kicks off...

 

[scooby074]

That could have been a hell of a lot worse. Glad it wasnt

Id be suspect of all the lifts there. Looks like some ****** concrete.

Like the others i too am surprised at what companies get away with as far as foundations for a lift, let alone one that is overhead. Four posters FTW.

Might be worth a call to your state workplace safety. I for one wouldnt like to read on GJ about the lift accident that killed either you or one of your coworkers.

If yours failed, id bet the others arent far behind. A thorough inspection of them all should be in order.

 

[Dragster Racer]

I'm having trouble seeing the failure properly from the pictrure. Glad no one was hurt!
Do you think that the truck was loaded front or back heavy? It's hard enough to figure the center of gravity of a vehicle you are familiar with. Let along every other person's vehicle.
Is there a good way to determine the c/g of a vehicle? I worry about that with my new-to-me two post lift. When you think about it, there shouldn't be much stress trying to tip the columns inward, due to the overhead beam. Forward and back however.....if the weight is not centered well, that really worries me. How do you know?

 

[rickycobra]

I'm glad your ok, I hope everyone today is checking their concrete to make sure it's safe. I hope everyone that cut a few corners are reconsidering the slab thickness choice and are considering either not using the lift or giving more stability to the slab.

 

[tdkkart]

The only part that really worries me, is that I've put bigger vehicles on these kinds of lifts. And there are 10 bays in the shop, 7 have lifts identical to this one. If this one is like that, who's to say all the bays arent like that. I think this in one of those issues I'll bring up to corporate.

That's what has me wondering, this was not a lift failure, it was a concrete failure. What's the concrete like in the rest of the building??

 

[brownbagg]

as a concrete inspector, from the picture that is just bad concrete, nothing to do with the lift or installment. as long as the concrete place to spec, a two post lift is fine

 

[Silverback51]

Concrete is fine in compression, but with a two post lift, the side that failed in the picture is in tension. Concrete ***** in tension. Unless there is rebar taking the tension loads, it greatly increases the chances that it will fail.

 

[Dan in Pasadena]

yep. i feel they should have a footing under each post with J bolts (all engineered) not the redheads into a couple inches of godknowswhatpsi slab that is deemed acceptable.

x100. Just courting a tragedy that way.

 

[BB70]

me thinks he used only 1 leg under the vehicle instead of using all 4 & lifting the whole truck.

 

[Aberdale]

It's hard to believe there would be that much stress if the vehicle was only 6" off the floor. The center-of-gravity must have been way, way off, or the concrete was already cracked long before this, and it just happened to pop out the loose chunk.

My vote is bad concrete.

Dale

 

[WNYflyer]

As others have said, glad you are okay.

Those two post lifts scare me, the reason why is if you look at the foundation requirements typically alluded to on the lift manufacturer's web site they typically look like BS to me. Of course I basically design foundations for a living thus why their recommendations scare me.

If you really want to raise the hair on your neck look at the recently updated Mohawk new foundation recommendations and requirements. Compare those to some of the other manufacturer's internet recommendations and you maybe very surprised at the differences. I see Shadowdog500 put a link up already for Mohawk. All two post lifts are virtually the same loading wise for a given capacity thus shouldn't be much difference in foundation requirements.

Looks like bad "punky" concrete along with a what looks like a joint in the slab close to the base plate. Both bad news. For interior equipment the bolt material is seldom the problem, problem is typically concrete in nature. i.e. bad concrete, joints, bolt embedment.

 

[James E]

With the truck six inches off the ground, the arms are actually exerting more inward torque at the baseplate than if the truck was higher up in the air. The truck weighs the same at 6 inches high as it does at 6 feet, but the higher up the truck goes, the further away the fulcrum gets from the baseplate.

 

[Dragster Racer]

Actually, the farther away from the pivot point the force is acting, the more influence that force has as a form of torque. I really enjoyed Statics class.

 

[CBradio]

I did have all 4 arms under the truck. Its an Asymetrical lift, so when I moved the rear arms out, the front arms were underneath the vehicle. I went ahead and put them under the front lift points on the frame. Everything we do in the shop is on video, and if caught using two arms it means immediate dismissal.

As for the knowing how to lift/center of gravity thing... The lifts at our shop have a 'stop' pad on the floor. FWD vehicles and light cars go over the first bump. Heavy vehicles go over the second bump. Its a rough idea of how to distribute the vehicles weight on the lift.

 

[Dragster Racer]

Please don't think I assumed you did wrong. I just asked. It's pretty hard to tell for sure on all vehicles.

 

[Cryptic1911]

that concrete looks terrible.. probably done 40 years ago without lifts in mind. I wouldn't get under any lifts in that shop until they redo the floor

 

[79firebird]

to close to an expansion joint for one thing and it looks like a bad mix. might not be thick enuf also. mabey no rebar?

 

[Ironcrow]

There's just too much leverage force, and as the lift goes higher is gets worse and worse.

The twisting force, turning the lift over, at the base is independent of the height of the lift arms/load.

I also discussed putting J-hooks into the concrete with the local Mohawk dealer/installer and he strongly advised against it, because most of the time they are not installed exactly and dont line up with the holes in the bottom of the lift.

This is the way I did mine. I created a template of the lift base out of a piece of plywood, mounted the bolts on that, and cast it in when I placed the pad. Easy and accurate. I wouldn't let this contractor scare me.

All two post lifts are virtually the same loading wise for a given capacity thus shouldn't be much difference in foundation requirements.

Part of the reason I picked a Benwil is precisely because its footprint IS different. Substantial welded gussets and longitudinally extended base plates, about 3 feet long and displaced to the rear of the lift column. Means this asymmetric lift would stay upright it the J bolts somehow magically disappeared. The CG of the car is within the lift footprint. I still anchored the J bolts to the rebar mesh.

 

[CBradio]

Well the company concrete guys came in yesterday. Apparently code for the shop is only 4.5 inches of concrete, but we have almost 8 with no rebar.

And dragster, no offense taken.

 

[scooby074]

Well the company concrete guys came in yesterday. Apparently code for the shop is only 4.5 inches of concrete, but we have almost 8 with no rebar.

And dragster, no offense taken.

so what are they going to do?

Looking at the pics, the concrete itself is bad. Looks "sandy"?

And no rebar

They should at least pour new footings for the lift with good concrete/rebar.

 

[CBradio]

They came in, cut a 4'x4' section out, filled it with concrete they made out of bags of concrete, and let it sit for a week. No skim coat. its about 1/4 inch below the rest of the concrete. They came in two days ago and put the lift back in place and apparently now its 'functional'. No idea if its safe, but its 'functional'.