Cieling Support Two Post Lift

[Zrxpilot]

I am installing a 10,000 lb two post lift next weekend. The biggest thing going on it will be my HD 2500 4X4 (under 7000 lbs).

My first time doing it. Been reading everything I can get my hands on. Got a good grip on it I think.


I have an idea that I have not seen addressed. My lift is coming in very close to my ceiling. (ceiling is 13' tall) and the lift is 12'-7".


Is there any reason why I cannot fasten the top of the lift directly to the ceiling for added safety? I understand that maybe thermal expansion might be an issue. that being the case (or not), I could also install a bracket or stopper on both sides of the lift beams at the top (like book ends) that would allow the lift to grow in height but would not allow any lateral movement.

This seems like something that should be done on every lift installation but what do I know. It sure wouldn't be much work to accomplish.


Your thoughts are appreciated

 

[QwikKotaTx]

I would not be overly worried about thermal expansion. The linear (vertical) expansion on that height of a steel member is only 0.11" with a temp swing from 0°F to 100°F.

 

[Flexia]

Well my thinking is that if it does flex or fall that it will be tied to a weak truss and then the roof would follow the lift

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[SteveCh]

Not an engineer [disclaimer]. However, even if it doesn't hurt anything, I have a hard time figuring it will be of any benefit.

 

[Zrxpilot]

I used even a wider temperature spread (-40 to +110 f) and came up with less than 5/32 total spread from cold to hot. The growth upward is negligible.

The benefit seems obvious to me. It could not tip over. Trust me, my trusses aren't moving with a 7000lb lateral movement unless it was sudden. And even then, if the worst case scenario played out...the condition of my roof would be the last of my worries. The retrofit is easy. Just wondering why nobody does it.

 

[keelan]

What about forces perpendicular to your trusses? Seems like it wouldn't take much force to bow your trusses out and cause all sorts of potential 'domino' situations.

I think nobody's done it because the effort vs. benefit analysis always comes up unfavourably. Ceilings aren't meant to take that kind of load, and the lift is engineered to be installed without being attached to your ceiling, so why bother? The 'No' column fills up much quicker than the 'Yes' on this one.

 

[avc8130]

What type of lift are you installing? I've been in countless professional shops using lifts to their rated capacities. I have NEVER seen a lift tied to a ceiling.

ac

 

[volaredon]

Not an engineer [disclaimer]. However, even if it doesn't hurt anything, I have a hard time figuring it will be of any benefit.

I agree unless your roof design is weak to begin with

 

[volaredon]

I used even a wider temperature spread (-40 to +110 f) and came up with less than 5/32 total spread from cold to hot. The growth upward is negligible.

The benefit seems obvious to me. It could not tip over. Trust me, my trusses aren't moving with a 7000lb lateral movement unless it was sudden. And even then, if the worst case scenario played out...the condition of my roof would be the last of my worries. The retrofit is easy. Just wondering why nobody does it.

because if the colums DID fall or twist, youd bring the house down with them.
You said yourself/ "nobody else" does this. so why detract from "normal" in this case? Don't fix what aint broke.

If you are at all worried about it falling then I'd be real leery of your concrete and anchoring job! or you have one of these lifts that they show on You Tube that failed... if you buy a decent NAME BRAND lift (no I don't mean "atlas" either) and your concrete is good then you have no worries.

 

[wssix99]

because if the colums DID fall or twist, youd bring the house down with them.

Correct. Floors and roofs above aren't engineered for these kinds of loads. (Typically they are designed for distributed loads acting from the top.). Any lateral sway in the lift could do damage to what is above unless you consult an engineer and the lift manufacturer to design the connection.

 

[fnieto]

Do not secure the top to the ceiling. You should be really thinking about placement (layout) of your new lift.
best of luck.

 

[JakeKohl]

Well my thinking is that if it does flex or fall that it will be tied to a weak truss and then the roof would follow the lift

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^^^THIS^^^

It doesn't really offer much advantage but it does drastically change the failure mode from "god-awful" to "potentially catastrophic". Install it as designed and don't attach it to the ceiling.

 

[LX-Markham]

Definitely would have to be checked by an engineer to see if the bottom chord of the trusses could handle any lateral load. A diaphragm or series of x-bridging would be required at the very least.

As for your question: you would need to provide a vertically slotted connection between the lift posts and the joists. The roof joists are going to deflect vertically under load. You don't want the joist to apply additional load to the lift posts. Conversely, you don't want the posts to act as a mid support for the roof joists.

 

[jimkaniki]

What about forces perpendicular to your trusses? Seems like it wouldn't take much force to bow your trusses out and cause all sorts of potential 'domino' situations.....

Ditto that. The whole reason trusses work is that they have triangles made of relatively slender boards oriented in a vertical plan. If you mess up the vertical plane, there's no telling how the truss will react.

If you were assured that the forces imposed by the lift would be entirely longitudinal along the bottom of the trusses, then maybe that would be OK. The trusses, however, will put up little resistance to twisting or side-to-side forces.

 

[James E]

Lift won't fall straight down, it will fall to the front-back-sides. No matter what the ceiling construction--but especially with trusses--it is not engineered to hold up to a side-load.

Best case in a lift failure would be that the lag bolts connecting it to the ceiling would rip out and cause a mess. Worst case would be that the lift would tear out one or more trusses on the way down and create more damage, more debris and more cost to fix.

If the lift sways enough that attaching it to the ceiling will stop it from moving, then it's not secured to the floor well enough.

 

[Zrxpilot]

Thanks much for the responses. The lift is a 10,000 lb Atlas. XW/XT version. I have not installed it yet and currently going thru the planning stage. Installing this directly under a truss is an option that I have today as I have not installed it yet. I was not suggesting this as an alternative to performing insufficient floor mounting practice.

Message heard loud and clear. 12 consecutive responses all saying nay is enough for me.

 

[James E]

I have to chime in that your question is not an unreasonable one. Securing the lift to the ceiling is actually a good idea IF and only IF you build the building in a way that it could support the lift if it fails--and that would be prohibitively expensive. You'd be talking about building in not only structural beams in the ceiling, but beefed up wall framing to support it. It's just not worth it, IMO, which is why nobody does it.

Some of that money is much better spent beefing up your slab if you have worries about support.

When it's all said and done, I think most lift failures are mechanical and not structural, anyway. That is to say, a cable breaks or a ram seal fails or a lift arm slips or bends. None of those will be made any better by having the lift supported from above.

 

[bobadame]

I think it's a great idea and it's on my list of things to do someday. I plan on attaching the top of the lift columns to the i-beams that support the roof and upper story of my shop. I'll do this with a couple of steel straps at a shallow angle to allow for movement of the building relative to the floor. 2 straps per column. My thinking is that this would be a brace against the lift tipping. The tipping force at the tops of the columns is very small compared to the total weight of the lift and it's load. The idea is to prevent the lift from tipping the first couple of degrees and I don't think it would take much to accomplish this.

 

[jonzer12]

The only possible reason I could for doing that is if you want to put something heavy in the attic directly above the lift.

If that is not the case,
Install the lift properly, following the instructions and enjoy it. leave your ceiling alone.
You are trying to solve a problem that should not exist.

 

[wssix99]

I think it's a great idea and it's on my list of things to do someday. I plan on attaching the top of the lift columns to the i-beams that support the roof and upper story of my shop.

This is still a bad idea unless detailed engineering is done. Just because an I beam is steel, doesn't mean that it is stronger under a lateral load compared to a wood truss. A lateral push on a steel beam can cause it to fail. (Depending on the load it supports, how it is braced, the section of the beam, etc.)