Four Post Lifts and Earthquake Safety

[mslisaj]

I have a Pro Park 9 Plus four post lift. I bought it mainly for storage to get that less used car up and out of the way. Well I just rearranged my shop and now I have a BIG 66 New Yorker up in the air. It weighs about 4200 pounds or so and this lift is good for 9000 so this is an easy lift. But as I stood back and looked at that land yacht up in the air I got thinking about an earthquake.

The lift is installed on a new, level 5" thick 3000# concrete floor. It's bolted down as per recommendations with 3/4" wedge lock fasteners to the rebar enforced concrete floor. In my reading about this situation it was brought up that the car should be tied to the lift as it's most likely to get tossed off and not the lift failing. I never thought about that. But like most folks I have a show vehicle under this car and I am truly wondering what the risks are here. Of course in a big enough earthquake most everything would come tumbling down but I am just soliciting others thoughts and ideas on this situation.

Thank you for taking your time to comment or add your suggestions.

Lisa

 

[c39er]

I've also looked online endlessly trying to find stories of earthquakes and cars on lifts....zilch-nothing.
Guess nothing happens!

 

[mslisaj]

Well I have kind of come to that conclusion too. I remember a few years ago I think it was a hurricane or tornado that tore up a new car dealership. They showed pictures of the building destroyed but the two post lifts still standing and some of them had cars in the air.

As I mentioned in my "research" the point was made to tie the car to the lift to keep it there and that kind of made sense. But this big Chrysler is kind of captive up there one way or another because it's longer then the posts and other barriers. But there is a lack of evidence to show that cars come off these lifts or the lifts fail. So even your comments are "some" comfort to me.

Thanks for your time and other comments are always welcome too.

Lisa

 

[brass89]

So long as the concrete holds and is designed for earthquake resistance, a 4 post lift is pretty sturdy but I could see a nasty earthquake pitching the car off. If the car is seldom used, what about some chains at opposing corners with chain binders? Similar to what semi's use for flatbed and tow trucks use to secure a vehicle? Should be a fairly low cost solution, binders have chain slots on them to adjust the chain as needed and they're pretty quick to connect/disconnect. Tying opposite sides down (ie, left front and right rear) should be enough to keep the car from being pitched off front or back and eliminate side to side pitch/roll. Just be sure to hook to the frame somehow, not around control arms, axles and whatnot. As it tightens down it'll compress the suspension a little and further take potential pitch and roll out of it.

 

[mslisaj]

Yes I am certainly open to tying the car down and two binders at opposite corners makes great sense. Also you point of preloading the suspension to keep the body from gaining momentum is a point well taken. I read someone recommend straps around the tires to hold the car down but I actually like securing the body better.

Great idea.

Lisa

 

[LX-Markham]

I'd contact Direct Lift.
Some commercial 4-post lifts are seismically approved.

 

[justsam]

I did have a car on a lift during the recent Napa earthquake.
I am located in Penngrove which is about 20 miles NW of the epic center. Quake was a 6.0.
It certainly woke me and all my neighbors up, and I realized I had a car up on the lift in my back garage. It is a 4 post that is not anchored, but free standing, 7000lb capacity.
I had left my 996 Porsche not well positioned on the lift because I was doing some work on the lower front and had the front end hanging over a bit as opposed to centered front to back.
Clearly I was not out in the garage when it occurred at about 3:30AM, but I was there very shortly after. The wheels were blocked and I did not observe that the car had shifted at all. It did make me nervous enough to lower it in case of after shocks. No harm done

 

[BRIANBB]

The big car on the lift will protect the show car underneath from the falling roof!

 

[paranoid56]

if you have a large enough earthquake that will make that car move off the lift, you house will also be rubble, as that would have to be one large earthquake.

 

[brass89]

problem with earthquakes, they're unpredictable. some hit certain areas harder, depends if it's a rolling or shaking quake, the intensity of the aftershocks..sometimes aftershocks can do more damage even if they're less strong than the initial tremor. look at the quake in s.f. in 1989, took out a huge section of the bay bridge. many houses survived, some didn't. in some places the concrete rolled with no harm, in others it cracked and blew apart.

 

[mslisaj]

Well I would have to agree with parinoid56. It's prudent to tie the car to the lift to keep if from moving but if that lift fails the house and the shop are rubble anyway. I grew up in California and have lived through all the recent major earth quakes so I am not new that phenomina. In fact I find it interesting but I have looked around my shop and wondered how my loft and other things would fair in a good shaker.

BTW, I just got a response from my question to Direct Lift on the seismic question. I was told their lifts were no specifically tested for earthquakes and they did not have any reports of how their lifts may have faired in recent quakes. So there is the official response too.

Appreciatre all the comments and I do have other things that concern me besides this lift and that car on it.

Thanks again,

Lisa

 

[Steevo]

All I can say is " I hate you".
Not really, but I am definitely jealous of someone who has a '66 Chrysler New Yorker up on the lift, AND a "SHOW CAR" under it.


Damn!

 

[mslisaj]

Well Steevo it's like this. First off I am old enough to have accumulated all this stuff that now I spend my retirement and time on keeping it all running. The 66 New Yorker was my mother's and it's in perfect shape but needs paint. The 440 in it has 5,000 miles on a complete overhaul and all the accessories work in the car. The picture I use for me "avatar" kind of shows everything. The vehicle featured on the top of the four poster is a 53 Ford Pickup that I literally transplanted an entire 68 New Yorker into. It's a Chrysler product right down the the Chrysler dashboard complete, 440 six pak and all the Chrysler New Yorker wiring. It now sits under the big Chrysler on the four poster. The other car in the picture is a 65 Plymouth Satellite that I drove to high school. It has a factory 426 wedge engine in it with a six pak also. I also put a Dana 60 in the rear for all the true Chrysler boys. So now you know what and where it all is and I would hate that big car to come off the top and cascade down and take everything with it. Just the little old lady in me.

Have a great day Steevo and now you have reason to really hate me.

Regards,

Lisa

 

[sherlocktk]

I would think that it would be better to strap the tires to the lift than chaining the body. The springs and shocks would help absorb the earthquake movement and therefore reduce the amount of stress transferred to the lift. This is not like a trailer you are trying to not have 2 dynamic loads. The lift is a static load the vehicle is dynamic, which helps absorb the "vibrations" of the earthquake.

 

[skiingman]

if you have a large enough earthquake that will make that car move off the lift, you house will also be rubble, as that would have to be one large earthquake.

Yeah that's what I was thinking.

The car on the four post comes with four springs with shocks to damp any motions and big sticky rubber tires to keep it from sliding around. Think about what it takes on a road to make a car leave the ground, or even lift a single wheel. I think the earthquake that would shake a car off a four post lift would leave the car as the very least of anyone's problems. Structural failure of the lift itself seems a heck of a lot more likely.

 

[mslisaj]

Well gentlemen, I agree and disagree. First I agree with Brass89. I think securing the car tightly to the lift makes it all one moment of movement as it all won't move together. Think of the lift moving left and then a half a second later the car moves to the left. Then the lift moves to the right while the car is still moving to the left and now it has to catch up and that moment of movement is now accelerating to catch up and repeat that a few times and the car will be flying around with the inertia that it's developing. So I will have a tendency to make the lift and the car as one element as I can. The name of the game is to keep the car ON the lift. Now I do agree with Skiingman as the real problem will be with the structural failure of the violent movement of the lift itself. If the car is going to come off the lift then the motion is so violent that the entire building will be come crashing down.

Another way to think of this is if you held a "bobble head man" in your hand. Now you start to shake the body. Your hand to body contact represents the tires tied down to the lift. You start to shake the little "bobble head man" and his head is violently trying to catch up until you break the head off the spring and body. I think this is how the car would react.

Great discussion gentlemen and it puts us all to thinking.

Lisa

 

[c39er]

Bendpak ought to know as they are out of southern cal.

 

[skiingman]

Another way to think of this is if you held a "bobble head man" in your hand. Now you start to shake the body. Your hand to body contact represents the tires tied down to the lift. You start to shake the little "bobble head man" and his head is violently trying to catch up until you break the head off the spring and body. I think this is how the car would react.

Great discussion gentlemen and it puts us all to thinking.

Lisa

Makes sense and I'm sure for some specific earthquake the car might get out of phase with the earth and make things worse. I think generally you'd be a lot better off with the car sitting up there than you would with a 3000lb block of concrete, as it seems likely the damped suspension will reduce the peak accelerations. Unlike the bobblehead the car has a tremendous amount of damping. It's tuned to take all sorts of motions at all sorts of speeds and damp them in half a cycle. To use another analogy, if you ever towed a car trailer they jump and bounce and rattle at the slightest road vibration. When you strap a car on everything is smooth as can be.

 

[akdiesel]

Well here is apples to apples in a sense. I have a 2000 lb porche speedster and some misc. items (cement mixer, axle, etc.) on my BendPak 9XW. The lift if locked in at the top location. No bolts to the floor or any other additional supporting / anchoring devices.
I was not in the shop at the time but we just had a registered 6.2 earthquake. No damage. I am sure it wobbled as they do when you rock a leg support by hand.
Not that I would stay under the lift in these situations but I feel safe knowing it can take this type of abuse.
I feel the less weight the quicker it moves but slows down faster. More mass will take longer to move but will move longer also.

 

[mslisaj]

I appreciate your observations. The more we discuss this here the better I feel about these types of lifts. I'm sure there have been a lot of four post lifts from different manufactures that have cars on them and survived many different types and sizes of earthquakes. I'm getting the impression now that if there was a problem of cars coming off four post lifts or the lifts fail there would be some warnings about it. I seem to have raised a subject that folks may have thought about but without a track record of failure there is no concern. The manufactures I'm sure have thought about it too. But again there have been no failures to study so the design and build is adequate for the job intended.

Two post or four post lifts are always something to marvel about and stand back and look at when it's one of YOUR cars up on it. I know for me I check and double check everything and I never forget the fact that there is a car over my head. But the more I work around them the more comfortable I get.

I appreciate everyone taking their time to offer feedback here.

Lisa

 

[c39er]

Someone needs to go to napa valley and find a repair shop with some lifts.
I'm sure one of the repair shops would be able to answer this question as they had a pretty good quake a couple months ago.

 

[brass89]

The only thing I was concerned with, if the ground (and foundation the lift is attached to) begins shaking the car's suspension won't deaden the sway/bounce. Springs want to push back and have a tendency to accelerate motion. Not to mention, the car's weight at a dead stop is x amount (curb weight). This weight will be increased during a bounce as it 'lands' compressing the springs yet again as the weight becomes a dynamic force. Chances are this weight will be applied unevenly during a quake so the dynamic force of the car being bounced 'up', its' weight will land off kilter and apply more stress to one side or one corner than the other(s). Lifts are designed to handle static loads, not dynamic ones. That's why my suggestion of compression on the springs, to take the 'bounce' out of it. Unfortunately I don't have any experience during a quake with a car on a lift, 4 post or otherwise..and even if I did I highly doubt any two situations would be the same.

Also keeping in mind this is more or less for safety during a worst case scenario since most smaller quakes wouldn't likely toss a car off the lift even if it weren't secured. This isn't for something along the lines of a 4 on the richter scale, more like a 5 or 6+ (considering the way the richter scale works, each number is double the energy of the quake rating below it - ie, a 4 is twice as strong as a 3, a 6 is twice as strong as a 5 and so on). I did grow up in the s.f. bay area and was living in the silicon valley when the '89 quake took out the marina district and the bay bridge. That was a fairly rough one at 7.2 and not overly common. They can get some stuff moving though lol.

I do think it'd take quite a bit to drop a car and completely collapse a lift (esp a 4 poster). If the quake is strong enough, it's going to do what it wants to do. All securing the car will do is minimize the risk, not eliminate it completely - which is really all anyone can do when taking safety precautions. Best bet is to not be under the car when a quake hits and keep fingers crossed there's minimal to no damage done to the vehicles or lift or people.

 

[akdiesel]

I would not say lifts are a static system. The rise and lower of the lift puts it in motion and I have seen a few lifts jolt some when stopping in the upper or lower position so the stress is built into the lifts for that as well.
I don't recall seeing vehicles jump on the road due to their spring suspension being worked when a 6.0 or greater earth quake is happening so I don't see how one could jump off a lift. That is not say it could not happen though.

 

[brass89]

Raising and lowering a lift, or the inch or so one might jerk with a car on it isn't the same as an earthquake. Not even close. That's like saying jumping off a roof won't cause any issue because we can safely step off a curb. You won't see vehicles 'jump' off the pavement really. What you also don't see is the up/down motion of a roller and the dynamic load of a car's weight increased on the road surface. Just like a person jumping. Standing on a curb, not moving (static load) I weigh 200lbs. I don't even have to jump. If I just lift up on my tip toes and 'drop' down, it'll be more like a weight of 250+. Dynamic stress (also referred to as live loads in building construction). It will become more evident though in a lift where it's load bearing is much less than that of asphalt and concrete with roadbase beneath it.

All I'm saying is a car bounces due to the motion of a flatbed wrecker going over the road (the flatbed being the surface the car is resting on). The amount of force of a wrecker bouncing over a bump in the road is very slight compared to a quake. When a quake hits, it will put the ground (base, and anything else attached to it like a lift) in motion just as the flatbed of a wrecker down the road. If pictures can fall off the wall, dishes fall out of cabinets with doors on them and appliances like microwaves fall off of an otherwise stationary platform, it would be safe to assume a car could be jolted off a lift. This all depends on the severity of the quake. Some just toss pictures off walls, others collapse bridges. I'd venture to say a bridge is a lot more sturdy and bears greater load than any lift. If a quake can take it down, it'll take down pretty much anything (and whatever's on it).

Strapping a car may not even prevent it from falling in the event of lift failure. But at least if a car is secured, it can't go off one end or the other and be pitched to a space outside that which the lift occupies. Say the lift collapses. With a car tied to it, the car stays with the lift. If the shaking disengages the safeties or for whatever reason allows the uprights to shift/spread under only half (say the back of the lift platforms), the car will now be like this \ instead of ---- and can come off.

This shows a 4 poster lift failure. Had the car been strapped down, the wheels wouldn't have hopped off the edge of the ramps, there's nothing to keep this vette from coming over the edge.

 

[Cobra5150]

If an earthquake shakes the car off of the lift, that's the least of your problems.

 

[Corsair4360]

We used to live in Santa Clara County California (glad to be gone). The 1989 Loma Prieta earthquake was less than 20 miles from were we lived and 5 miles from work (epicenter). That was a 6.8 event. My buddy has a car repair shop and nothing happened to the cars on the lifts (all in ground single post lifts) other than some shifted a bit on the arms.

All depends upon the the type of earthquake and the magnitude. I agree with others, if the car falls off the lift that will be the least of your worries.