2 Post Car Lift - recommendation

[Redrum]

Lift superstore will walk you through the whole shot you can download installation expectations and we’ll to be honest once it’s in your driveway you do with it whatever the hell you want I guess
But they do have interesting options for lifting
Peter

Thanks, been looking at this one. There is a showroom about 60 miles away. Would be nice to see one and hear about the options

https://liftsuperstore.com/product/dakota-symmetric-12000-lb-5-5t/

 

[Parminio]

Let me say this in a nice way and not come off as you do. Why must you phrase everything in a condescending and rude manor? You can disagree with someone without implying they are stupid and you know it all. Please just move on. You have contributed zero to this conversation.

It's only condescending and rude because you take it that way. Probably because you know it's true. No less than 4 people on this thread have told you you're doing it wrong. You are. There is, quite literally, no way on this planet that what you're doing is going to be "better" than what engineering and the laws of physics have told you is required.

That is a fact.

It's not rude.

It's not condescending.

It is FACT.

If you take it as an insult then that's on you.

An engineered solution is what's called-for here. You need to have a soil test, and then an engineer to do the calculations as to what will be weight-bearing sufficient to handle any possible load you introduce from your installation, and with a decent safety-factor.

On single story slab / footing all you really need to do is run a compactor over it several times, especially if you (as you should) gravel down and crush and run it for drainage.

The figures in the charts I posted take into consideration that is done when your slab is poured.

If you're going multiple story, absolutely call in a soil engineering company for compaction tests though. That's a must.

 

[Fire-medic]

On single story slab / footing all you really need to do is run a compactor over it several times, especially if you (as you should) gravel down and crush and run it for drainage.

I think you have a good intent, but for any type of potentially life-ending calamity arising from a structural collapse, an engineered solution is what is called-for. An example: the soil has a large depth of humus, decaying vegetative material, and whatever fauna that invites, like worms and insects. That is the type of material which needs to be removed and replaced with a more-stable material like compacted, crushed rock of a certain consistency. That gets done in 'lifts,' a specified depth of layers of inert material not vegetative. Then your base for the foundation is stable and weight-bearing. The process will be prescribed by the P.E. doing the calculations based upon a soil bore and lab analysis. Yes, that costs money. How-much is a life worth?

Some places may have very shallow depth to reach bedrock VT, probably, while other places like south FL may have deeper depths to reach stable subsoil composition. I know my neighbor decided to do 'lifts' to get a stable base upon which to put a slab and a CBS 1 story residential dwelling, and he had to excavate six feet plus, to reach limestone base upon-which he could do one-foot lifts of compacted material. The alternative was pilings driven in-place or screw pilings, which are less-likely to damage the foundations of your neighbors' houses on either side.

In some rural jurisdictions, none of this may be required. I'm thankful that we do have a strict set of regulations concerning site development. As a former licensed plans examiner, I know the importance of professional design and build criteria.

 

[Redrum]

Please don't take it as an offense but I plan on ignoring all your posts.

Have a great day!

 

[Pighuntingpuppy]

Please don't take it as an offense but I plan on ignoring all your posts.

Have a great day!

Good Luck. Dont Die.

 

[Redrum]

So Fire-medic you got me thinking I might do some math and then just overkill. I have no concerns about the soil as the surface area contacting the ground will be quite large. Probably 10 square feet per side. So at 10k lbs that's 10k lbs ÷ 2 sides ÷ 10 sq feet ÷ 144 convert to inches = 3.5 lbs per square inch. The soil is a very hard compacted clay/rock base with 2" of #52 limestone on top

I am concerned about the shear strength and the steel bending. So say I incorrectly load the car and there is 1000 lbs front load on both arms and they are 3 feet extended. Let's say the lift base is 1 foot wide where 2 bolts are attached. So 500 lbs per side with a negative level action of 3x there is a 1500 lb force on the 2 bolts. So 750 lbs per bolt. If the bolts each have a 2" washer with a 3/4 inch center hole that's approximately 2.7 square inches. So 750 lbs ÷ 2.7 = 278 lbs per square inch on a 1000 lb off center load. That is with 2 bolts. If you added 2 more at say 6" from the fulcrum, and they took 1/4 of the load would be 208.5 lbs per square inch.

If concern is the bending of the steel each side must be able to support 1500 lbs of force at 1 foot from the fulcrum. So flat steel is not a good option. Perhaps those plates they use on the highway to cover road construction might work but this will be in the ground so no need.

For tipping concerns I'll be anchoring the ends of the beams to the ground via a 8" hole about 3" deep filled with concrete and attached via an embedded threaded rod.

I'm leaving out other details but I wanted to address my concerns.

So I'll go to a structural steel scrap yard and get some "huge-***" steel




I wasn't going to go to the trouble of drawing this out but it helps me too.

I wonder if it would just be simpler or easier to use a concrete pad. Probably not a safe though.

Wonder where I could get an opinion on that, hummmm.

Well I didn't ask for an opinion on that so I guess none will be coming.

 

[Parminio]

I think you have a good intent, but for any type of potentially life-ending calamity arising from a structural collapse, an engineered solution is what is called-for.

My brother is a structural engineer and I worked for Holder Engineering for 3 years. I help build the Gwinnett Arena. It's this structure right here:

https://en.wikipedia.org/wiki/Gas_South_Arena
In fact, I was there shooting layout for pilings that would support the upper decks when 911 happened.

So I do have more than a decent understanding of what is required. The figures were already laid out in the link I posted. That is for single story structure, which is what he's going to have.

 

[Parminio]

For tipping concerns I'll be anchoring the ends of the beams to the ground via a 8" hole about 3" deep filled with concrete and attached via an embedded theaded rod.

That's not going to do it.

The object isn't to go deep. It's to go wide.

Going deep and skinny will lead to sheer. It will snap that piece of steel like a twig and/or shatter the concrete over time. It will also act like a shovel with the skinny concrete piling acting like the blade and the long, heavy lift beams the handle of the shovel.

There's a reason a shovel is built exactly like the setup you're describing: it works.

Here's a simple experiment:

Stand a new, unsharpened pencil on its end on your table. You'll find it very tricky to do. Then just touch the top of it and you'll find it tips right over.

That is sheer - that is going to happen every single time you lift and lower a car or truck as the weight of the front with engine/transmission fights to tip the lift forward over the lighter rear of the vehicle.

Then get yourself some double sided tape and try some experiments. Tape the pencil to a penny, then thump the top and watch it tip right over again, only not quite as easily.

That's what you'll be doing with your 8 inch piling.

Then tape it to a quarter. You'll find it a bit tougher but you can still thump the top and it will tip right over.

Then tape it to a tea cup / desert plate. It's not going to tip over no matter how hard you thump it. It will snap in half or rip the tape loose before that happens.

That's what you're going for.

That's why I said footing and not piling. A piling is done for vertical load, not lateral sheer, which is what a two post lift is going to give you. That's why the four post lift doesn't require steel rebar in the foundation at all and the two post does.

 

[Coastal Grey]

That's not going to do it.

The object isn't to go deep. It's to go wide.

Going deep and skinny will lead to sheer. It will snap that piece of steel like a twig and/or shatter the concrete over time. It will also act like a shovel with the skinny concrete piling acting like the blade and the long, heavy lift beams the handle of the shovel.

There's a reason a shovel is build exactly like the setup you're describing: it works.

Here's a simple experiment:

Stand a new, unsharpened pencil on its end on your table. You'll find it very tricky to do. Then just touch the top of it and you'll find it tips right over.

That is sheer - that is going to happen every single time you lift and lower a car or truck as the weight of the front with engine/transmission fights to tip the lift forward over the lighter rear of the vehicle.

Then get yourself some double sided tape and try some experiments. Tape the pencil to a penny, then thump the top and watch it tip right over again, only not quite as easily.

That's what you'll be doing with your 8 inch piling.

Then tape it to a quarter. You'll find it a bit tougher but you can still thump the top and it will tip right over.

Then tape it to a tea cup / desert plate. It's not going to tip over no matter how hard you thump it. It will snap in half or rip the tape loose before that happens.

That's what you're going for.

That's why I said footing and not piling. A piling is done for vertical load, not lateral sheer, which is what a two post lift is going to give you. That's why the four post lift doesn't require steel rebar in the foundation at all and the two post does.

You should really quit while you are ahead

 

[Parminio]

You should really quit while you are ahead

Why, exactly? I am factually correct. It's proven science and math.

Or had you rather him do it incorrectly as he is planning and about the 5th truck he puts on that lift the right side support snaps in half, tearing the lift in half and the whole kit and caboodle crushes him and anybody else unfortunate enough to be in the area to death instantly?

 

[Coastal Grey]

Why, exactly? I am factually correct. It's proven science and math.

Or had you rather him do it incorrectly as he is planning and about the 5th truck he puts on that lift the right side support snaps in half, tearing the lift in half and the whole kit and caboodle crushes him and anybody else unfortunate enough to be in the area to death instantly?

I think he got the point awhile ago

 

[Parminio]

I think he got the point awhile ago

Obviously, he didn't. He went from being dead set on never using any concrete at all and using steel plates that would end in disaster to now using a small, 8 inch concrete pile that isn't going to work either.

The real lunacy of it all is he claims he's prepared to spend $10,000.00.

He can have a top notch slab put in - I'm talking leveled, compacted, rebarred and poured - for around $3,500 to $5,000 depending on how large he wants his shop to be.

Then spend another $5,000 and have a good, top notch lift to put in it.

Yet for some reason he seems hell bent on doing something for 100 bucks that's going to get himself and anybody unfortunate enough to be in the area killed.

And for what?

 

[Screwloose]

redlinestands.com

You might have come across them already, but they give some advice on lifts and associated base’s, I never read their whole website but they get a bit of terminology wrong when the say tensile, they will mean compression.

Maybe help you a bit. Scary stuff dude

 

[Parminio]

redlinestands.com

You might have come across them already, but they give some advice on lifts and associated base’s, I never read their whole website but they get a bit of terminology wrong when the say tensile, they will mean compression.

Maybe help you a bit. Scary stuff dude

From their documentation:

• Do not install this lift on any surface other than concrete.
• Do not install this lift on a second level floor.
• Do not install this lift outdoors.
• Install lift on level floor only.
• Concrete must be a minimum of 4” thickness and 3,000 PSI.

 

[Redrum]

redlinestands.com

You might have come across them already, but they give some advice on lifts and associated base’s, I never read their whole website but they get a bit of terminology wrong when the say tensile, they will mean compression.

Maybe help you a bit. Scary stuff dude

Thanks, Lots of selection, I like that, but the "easy monthly payments" kind of sets off a trigger. Plus why is this CL16x 10x more expensive, $33k, wow. Maybe it's worth the extra??? That's why I'm looking in to this

Thinking this is a type-o and a foreign sales drop ship company. Could be wrong.

 

[Screwloose]

That’s good you got a bit of info from the website. Also I imagine you know, but I’ll say anyway, that if you use your own bolts/screwed rod that there are different grades, with different tensile strengths. And there are also many different grades of carbon steel plate, with different tensile strengths.

 

[Redrum]

That’s good you got a bit of info from the website. Also I imagine you know, but I’ll say anyway, that if you use your own bolts/screwed rod that there are different grades, with different tensile strengths. And there are also many different grades of carbon steel plate, with different tensile strengths.

Oh for sure. I'm not new and in fact pretty old. I will indeed go overboard on whatever I do with hardware.

A couple reasons why I like steel is there will be a positive lock on the beam bolt-nut. Not some side pressure that will not be as strong if the bolt loosens. Plus when concrete fails its an immediate, almost instant pop. Steel tends to be more gradual. Not that I'm planning on a failure either way.

Most cars, trucks, semi's, bridges and office buildings use steel rather than concrete as support. Luckily I have the opportunity to use that in my construction.

Just because everyone is doing it doesn't mean I can't do something better

I'm far from a sheep.

 

[Pighuntingpuppy]

Oh for sure. I'm not new and in fact pretty old. I will indeed go overboard on whatever I do with hardware.

A couple reasons why I like steel is there will be a positive lock on the beam bolt-nut. Not some side pressure that will not be as strong if the bolt loosens. Plus when concrete fails its an immediate, almost instant pop. Steel tends to be more gradual. Not that I'm planning on a failure either way.

Most cars, trucks, semi's, bridges and office buildings use steel rather than concrete as support. Luckily I have the opportunity to use that in my construction.

Just because everyone is doing it doesn't mean I can't do something better

I'm far from a sheep.

https://www.ky3.com/2021/11/11/report-interstate-bridges-crack-likely-dates-back-1970s/
Not that any steel bridges have collapsed in recent years. PA bridge recently and that 35W bridge that collapsed in Minnesota. But if you look at bridge collapses in the USA from the 60s onward, the steel ones failed even faster than the mason ones. Bear in mind, everything fails when outside forces damage things and everything will fail over time without proper maintenance. But the fact still remains, the manufacturers recommend for a reason. Failures tend to be higher with one material over another.

https://en.wikipedia.org/wiki/List_of_bridge_failures

 

[Screwloose]

https://www.ky3.com/2021/11/11/report-interstate-bridges-crack-likely-dates-back-1970s/https://en.wikipedia.org/wiki/List_of_bridge_failures

Bit of an eye opener.

 

[Parminio]

Plus why is this CL16x 10x more expensive, $33k, wow. Maybe it's worth the extra???

It's rated to lift 16,000 pounds, that's why. It's HUGE. And very, very strong.

To give you an idea, the curb weight of the typical 2021 F350 is between 5,800 and 7,700 pounds depending on options.

If you had the space, you could put one F350 on top of another and the CL16x would lift them both.

Complete overkill for anybody that isn't working on something like fleet trucks with really heavy towing packages and/or loaded with tools on them and the like.