Posts like those are why I have sberry on my ignore list.
Car Hoist Accident, Need Help!!
- Thread starter FordGuy1622
- Start date
Posts like those are why I have sberry on my ignore list.
Maybe I incorrectly decoded the sberry-nese but it didn't sound like nonsense to me. It sounded like he was just saying that there are engineers at these companies designing these systems, testing them, getting them certified in some cases and generally you should just follow the directions and installation instructions rather than engineering your own solution.
sberry
Banned
Whhat is nonsense is implying that the proper I stallation isn't adequate proven by the fact there are only a handfull of these yearly, most at least in part to operator error.
We ain't even seen a picture and we start engineering over an internet post witha 3 ft of concrete. That's the nonsense.
I been reading these long enough to spot it early, same way I can spot a hoarder in the first sentance. Advocating modifications to an engineered product with a whiz across a thread is what? Who would actually stamp this?
We ain't even seen a picture and we start engineering over an internet post witha 3 ft of concrete. That's the nonsense.
I been reading these long enough to spot it early, same way I can spot a hoarder in the first sentance. Advocating modifications to an engineered product with a whiz across a thread is what? Who would actually stamp this?
sberry
Banned
If someone comes on wanted to weld on live fuel tanks and modify pressure vessels or use plastic air pipe he would get slammed but we have a hoist failure and the crowd comes out with outright brain farts and we ahould jump on with a big "you go girl".
Sharpest stick here is the OP for looking for some advice,,, he just needs to sort the good from bad or practical at the least.
Sharpest stick here is the OP for looking for some advice,,, he just needs to sort the good from bad or practical at the least.
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sberry
Banned
I agree about soil density and even an engineer but now you figure to be the only one ever poured a footer too..I agree he needs help but poor help could be worse than none at all
rooster shooter
Well-known member
If you can't spell correctly, you lose all credibility.
sberry
Banned
I am on a phone.let but you can blow it out you **** too
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Rockett69
Well-known member
OP, I have worked on 2 post lifts my entire career, even put my own in. The advice I received was a minimum of 6" slab, however at work, they poured 18" conrete columns under the lift locations (Witnessed myself when the shop was added onto while picking these guys brains, and quite a specticle to watch it being done). I think you can cut the area around the boo boo and dig down to correct the issue, just be sure you have a crew that knows what theyre doing, any air pockets will compromise it (Common sense, I know) It has a lot to do with the footprint of the columns also. And maybe I missed it, but what kind of lift do you have? That will tell a bit more.
sberry
Banned
How would one be sure they knew what they were doing?
Rockett69
Well-known member
very true I suppose, one could only hope that there is a known reputable place in the area that has an upstanding record, but beyond that I suppose you're right, its a bit of a crapshoot. Its always a gamble when having to farm stuff out unless you know the people well. I don't personally enjoy having stuff done by others, but in instances like this, it would be out of my hands and would not have a choice to to leave it in their hands and hope that they are still in business for a reason.
bulletpruf
Well-known member
That's horseshit. Pure and simple. If this was a site for lawyers and someone couldn't spell, you might have a point because they read and write for a living.
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bulletpruf
Well-known member
Or just look in the manual for the brand and model of lift that you actually have.
I installed a 2 post lift with 9000 lb capacity in my garage several years ago. Bought one of the many brands manufactured in China, but was a company with a good reputation.
When I got it home and off the trailer, however, I could not believe how incredibly poor the directions were. I do recall there being a spec for concrete thickness, but pretty sure it was just 4" thick and 3000 PSI.
My point -- the manufacturer may not have detailed spec's.
Good luck. Waiting to see pictures.
Scott
bczygan
Well-known member
This thread is a good example, of the variety of information provided, as solutions for a problem.
Very little of this is useful to the OP.
And we can NOT give him any better suggestions until we know a LOT more about his existing conditions.
At the very least, we need to know what make and model of lift it is. And then the existing slab needs to be removed and the area prepared for an installation per the manufacturers instructions. At this point we could compare those recommendations with what was initially done.
These lifts act as columns without support at the top. Essentially they are a cantilevered beam in a vertical placement.
A variety of loads can be induced, based on how you load and balance the lift.
The connection of the lift to the slab and the construction of the slab, with it's steel reinforcement is all critical. It must follow the manufacturers engineered instructions.
From the OP's description, I can't tell if the connection to the slab also failed or just the slab itself. Photos are needed.
It would also be useful to find out exactly how he loaded the lift.
Bill
Very little of this is useful to the OP.
And we can NOT give him any better suggestions until we know a LOT more about his existing conditions.
At the very least, we need to know what make and model of lift it is. And then the existing slab needs to be removed and the area prepared for an installation per the manufacturers instructions. At this point we could compare those recommendations with what was initially done.
These lifts act as columns without support at the top. Essentially they are a cantilevered beam in a vertical placement.
A variety of loads can be induced, based on how you load and balance the lift.
The connection of the lift to the slab and the construction of the slab, with it's steel reinforcement is all critical. It must follow the manufacturers engineered instructions.
From the OP's description, I can't tell if the connection to the slab also failed or just the slab itself. Photos are needed.
It would also be useful to find out exactly how he loaded the lift.
Bill
Kevin54
MEMBER EMERITUS
With all of the bickering and horseshit being tossed out in this thread, I would be surprised if the OP even comes back.
sberry
Banned
He had a good question. Well not good but legit. Without simple pictures cant even see what went wrong. The shame in some of it is that the guys are probably geniuses especially compared to me where I have to use fingers to add on. I got a lot of respect for engineering, when I look back it was pitiful what I thought I knew, now I understand that some or most engineers are way over my head. It it needed sophisticated calculations or real schoolin I couldn't do it.
I am a great installer and estimator and do a fair amount of repair. I had a bud who I just couldn't have work for me anymore, way smarter but it was impossible to get him to understand a whole crew of pencil pushers already did this and that the failure was localized and needed 1.25 better and not 5 or 10X and in some cases that wasn't good anyway. Same with wire sizing, fukkin up my supplys and parts list, using up materials needed elsewhere and simply couldn't reason we were only putting 10A load on it already and was a size over as it was.
I ran in to another company owner says he fired this guy too, cant copy and do it the way the rest do, always got to put a spin on it.
Engineer says 4 inches of good material and supplies bolts, I wouldn't have an issue with 5 or even 6 inches and even a couple longer bolts on the back side. The excess cost is reasonable for a little insurance and doesn't stray too far from the code or change fundamental design.
I am a great installer and estimator and do a fair amount of repair. I had a bud who I just couldn't have work for me anymore, way smarter but it was impossible to get him to understand a whole crew of pencil pushers already did this and that the failure was localized and needed 1.25 better and not 5 or 10X and in some cases that wasn't good anyway. Same with wire sizing, fukkin up my supplys and parts list, using up materials needed elsewhere and simply couldn't reason we were only putting 10A load on it already and was a size over as it was.
I ran in to another company owner says he fired this guy too, cant copy and do it the way the rest do, always got to put a spin on it.
Engineer says 4 inches of good material and supplies bolts, I wouldn't have an issue with 5 or even 6 inches and even a couple longer bolts on the back side. The excess cost is reasonable for a little insurance and doesn't stray too far from the code or change fundamental design.
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nh_yota
Well-known member
Yep.
I'm no expert but if I were the OP I would contact the lift manufacturer to see what they say and contact a local engineer for an on-site opinion if needed. Lifts aren't rocket since and there are hundreds of thousands of them installed in auto shops and personal garages all over this country.
Opinions are like assholes - everyone has one.
sberry
Banned
Most of us need to be encouraged to be safe adequate installers of engineered equipment and follow codes and instructions. I see a quite a few failures, most are not due to the fact that it wasn't built right but after a repair where it was incomplete or assembled wrong once if left the factory. Some at dealers where turn over is higher and employees havnt been trained, are not career types and experts on particular equipment.
One of my Buds works for a tile excavator. A company owner who is fundamentally a sharp guy but there are some places he just knows more about it than most people do.
Likes to fancy himself an engine expert and dabbles in welding engineering. Scott says he tries to send him elsewhere, when he goes on vacation the place speeds up. Got to mess with everything. Has his own special torque specs but the reality is doesn't know enough to make sure a guy puts it together right or cant seem to read that part of the book.
I did that last summer, didn't clean the machine as good as I should and a gob of grease covers the timing instructions. Right in front of me and I do it wrong anyway, figure it out after and it seems like it would work but,,, I put it together the way it came apart, the PO had done this too, it did work but the difference between myself and the genius is I was willing to take it apart again which was fast by now and do it again, no math involved, no more rationale figuring It wont make a difference etc. My line of thought being they went to the trouble of putting instructions right in front of it from John Deere and I dumb enough to miss it, how much of a shot any one figure I got doing it some other way?
One of my Buds works for a tile excavator. A company owner who is fundamentally a sharp guy but there are some places he just knows more about it than most people do.
Likes to fancy himself an engine expert and dabbles in welding engineering. Scott says he tries to send him elsewhere, when he goes on vacation the place speeds up. Got to mess with everything. Has his own special torque specs but the reality is doesn't know enough to make sure a guy puts it together right or cant seem to read that part of the book.
I did that last summer, didn't clean the machine as good as I should and a gob of grease covers the timing instructions. Right in front of me and I do it wrong anyway, figure it out after and it seems like it would work but,,, I put it together the way it came apart, the PO had done this too, it did work but the difference between myself and the genius is I was willing to take it apart again which was fast by now and do it again, no math involved, no more rationale figuring It wont make a difference etc. My line of thought being they went to the trouble of putting instructions right in front of it from John Deere and I dumb enough to miss it, how much of a shot any one figure I got doing it some other way?
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When the father in law had his shop built, as they were pouring he dug footers where he knew a lift was going in eventually, and had them pour 6" I believe. 6 is the minimum I would go IMO. In all honestly when I build my shop my plans are for 8" thick where I'm going to be installing my lifts. Should be more than sufficient
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Sent from my iPhone using Tapatalk
sberry
Banned
I have never seen one pulled out in the real world, never hear od one. A real dealer likely has, I have heard of a couple dropped pickup trucks over the years, one being the muffler man with part time help.
bczygan
Well-known member
A lot of talk in these pad discussions about the thickness of the concrete. Some may think it is the weight of the concrete that determines how well the concrete resists the loads. This isn't the main thing. Nor is the compressive strength (PSI) of the concrete, past a certain minimum.
It is the steel within the concrete, that gives it tensile strength and creates a beam that resists the loads that the lift imparts. This makes the concrete slab where the steel is, a beam that acts in multiple directions (More in some than others) to resist the cantilevered loads that the lift creates.
Bill
It is the steel within the concrete, that gives it tensile strength and creates a beam that resists the loads that the lift imparts. This makes the concrete slab where the steel is, a beam that acts in multiple directions (More in some than others) to resist the cantilevered loads that the lift creates.
Bill
rooster shooter
Well-known member
We all read and write on a daily basis. I hope you don't use the same logic in math.
bulletpruf
Well-known member
I happen to have a law degree. And I'm pretty good with reading and writing.
I have installed exactly one lift. In 2008. It worked out fine.
On the other hand, you have random Garage Journal member who installs lifts for a living. He has done hundreds of them, and has personally seen a few failures caused by issues with inadequate concrete.
Whose opinion would you trust more? Mine, just because I don't have any spelling or grammar mistakes in my posts?
Jinks
Well-known member
I agree Kevin. Seems to be happening a lot lately & kind of disappoints me with a lot of the posters here.
sberry
Banned
This is the kind of logic that one comes up with then they don't know anything about it but want to add 2 cents anyway. But it really distracts from my original point, we havnt even seen a picture to see is a bolt broke, pulled out, cement cracked, bolts loose, did the thing fall over and we can come up with a dozen different engineering solutions involving all kinds of different schemes to a diy guy.
Not one single fact except there is a problem.
gunguy
Well-known member
Since the floor failed while the lift was under load, I would also have the lift inspected for any damage caused by the floor failure.
Jim
Jim
Well, in the OP he did say the cement cracked so I think there is at least a flooring material failure. There might also be something failed on the lift too.
Yeah good point. Definitely need to see if the lift was damaged as well.
anndel
Well-known member
From your description, it looks like it's not the concrete but high early strength (5,000 psi or better) wouldn't hurt. Looks like the soils beneath the slab can't support the slab let alone the lift with a vehicle on it. You may need a geotechnical or foundations engineer look at it to see if it'll hold or need better material. Good luck
pstnbly
Well-known member
Before I poured my floor I placed a sub-footing below where my lift was going to be. I placed anchor bolts in the footing. I made a full scale template of the footprint of my lift. Then I made up bridles of 3x3x1/4" angle iron to mirror the base plates of my lift drilled to match the mounting holes of the lift and the anchor bolts on the sub-footing.
I used 1" alloy allthread double nutted to the bridle for anchors for the lift and bolted the bridle to the sub-footing. After bolting the bridles down I placed my template on top and nutted it in place to align the alltread during the pour. I place a 6" reinforced slab over the sub-footing and bridle arrangement.
I'm confident it's bomb proof.
bczygan
Well-known member
Based on.....................................?
I think what you are describing is how you secured the lift to the slab and sub footing with vertical bolts and bridles.
But what was the arrangement and sizing of the horizontal steel reinforcing in the slab and sub footing? That is where the resistance to moment forces in the slab comes from.
I suspect the OP's slab had inadequate reinforcing.
Bill
pepi
Well-known member
pstnbly
Well-known member
I suspect the OP's slab had inadequate reinforcing.
Bill[/QUOTE]
No argument from me.
My floor is adequately reinforced. My point I'm not relying on wedge anchors that I'm confident have less withdrawal resistance than a poured inplace bridle bolted to a sub-footing that provides 15' sq rather than 8 wedge bolts that provide mere sq inches and also add unequal lateral loads to the concrete depending on how the lift is loaded.
Bill[/QUOTE]
No argument from me.
My floor is adequately reinforced. My point I'm not relying on wedge anchors that I'm confident have less withdrawal resistance than a poured inplace bridle bolted to a sub-footing that provides 15' sq rather than 8 wedge bolts that provide mere sq inches and also add unequal lateral loads to the concrete depending on how the lift is loaded.
DougWil
Well-known member
4" is a marginal slab thickness for a shop.
The concrete strength even before on site dilution and reinforcement were probably minimal too.
Most 1/2"-5/8" mechanical anchors with such a thin slab have only 1000-1500 lbs or so of allowable tension force.
That isn't much to counter a 6000 lb vehicle, eccentrically loaded on a long leverage arm.
The concrete strength even before on site dilution and reinforcement were probably minimal too.
Most 1/2"-5/8" mechanical anchors with such a thin slab have only 1000-1500 lbs or so of allowable tension force.
That isn't much to counter a 6000 lb vehicle, eccentrically loaded on a long leverage arm.
Fordguy1964
Well-known member
Strange thing happened to me. My air compressor started to make strange noises. It completely changed its note. It started sounding "deeper". I tore into the compressor trying to figure out what was going on. It just happened that about 3 weeks later I was around back of my garage where I have storage. I had to move everything away from the back of the garage and I saw a big pile of dirt. Come to find out that an entire colony (if that's the right term) of red foxes (not the comedian cause it sure wasn't funny!) had dug under the slab and made a den in there! It was huge! They dug all the way back under the slab to where it was hollow under it in that area. It took months to get rid of them but I was finally successful! Luckily they were not under the loaded part of my floor!
Have you checked to see your floor hasn't been undermined? It sure was a surprise when I found mine. Just saying.
Have you checked to see your floor hasn't been undermined? It sure was a surprise when I found mine. Just saying.
DougWil
Well-known member
Different Ford guy.
FordGuy1622 vs Fordguy1964
The OP really hasn't been back since his Help! request, and certainly not with any relevant info about the hoist model, 2 or 4 post, pics or anything.
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Fordguy1964
Well-known member
Wow... Just noticed that... Guess us "FordGuy"s have a common concrete problem. I was just asking because I have seen what a skulk of foxes can do.... Learn something every day. I wonder what a group of comedian Redd Foxxes would be called?
Just thinking aloud about the possibility of an undermined slab.
Just thinking aloud about the possibility of an undermined slab.
A riot? (two ways to take that)
lakeroadster
Well-known member
Pictures make it real. This thread is pretty much worthless without them.
A sub-grade issue is likely the culprit. Either the sub-grade wasn't compacted correctly prior to pouring the concrete, or it has been disturbed since the pour.
The fact is, if you run the numbers, the loading of the slab-on-grade itself is minimal with a 2 post lift.... assuming the slab is well supported by the sub-grade.
This is confirmed by reputable manufacturers selling thousands of lifts where the manufacturer only specifies a 4-1/4" thick slab made of 3,000 psi concrete.
A sub-grade issue is likely the culprit. Either the sub-grade wasn't compacted correctly prior to pouring the concrete, or it has been disturbed since the pour.
The fact is, if you run the numbers, the loading of the slab-on-grade itself is minimal with a 2 post lift.... assuming the slab is well supported by the sub-grade.
This is confirmed by reputable manufacturers selling thousands of lifts where the manufacturer only specifies a 4-1/4" thick slab made of 3,000 psi concrete.
rooster shooter
Well-known member
Yet you continue to opine without any real information. Insult me if you wish, poo poo the idea, but proper spelling is important.