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2 Post Lift Install - Anchors or Epoxy? Other Tips???
- Thread starter OldNeons
- Start date
I agree, but two-post lifts can NEVER be loaded perfectly, so there will always be some force lifting one side or the other.Compare the area of the lift's footings with the contact patch area of the vehicle's tires. Does the vehicle collapse the concrete when pulled into the garage? Then the weight of it on the lift is no different, hence no need for 2-foot deep footings. In fact, it's probably spread out more so than when the weight is on the contact patch of the tire.
Longer anchors, epoxy, etc. might be cheap insurance, but if you're putting yourself in a position where the lift may be pulled from the slab, you've made a significant mistake in loading the vehicle on the lift (asymmetrical load, removing weight creating an imbalance, etc.). Two-post lifts aren't designed to be loaded in a manner where there might be uplift in any direction. That's a user error. Loaded properly and the fasteners shouldn't be an issue.
Given that nothing is perfect, just trying to build in margin for some unfortunate error later on.
wssix99
Well-known member
I had a lot of problems with sleeve and wedge anchors until I purchased a good drill and started buying good drill bits. (I also throw them away when they start to get worn.) I no longer have any problems.I have been using them for decades and have not had one pull out. I used sleeve and wedge anchors prior and I couldn’t count the amount of failures I had.
Where are you seeing data showing them pulling out?
That being said, I personally do use screw anchors for most of my work. I like them in shear and for light tensile loads but don't use them for any heavy tensile loading. (Most epoxies are also "creep" and are bad under sustained tensile loading. Some posters on this site have used epoxy for their lifts and not checked for this important spec.)
The details on how to use these anchors are in engineering design guides, which are not freely available but here is a link to a scholarly article that can be purchased where a researcher tested screw anchors and found them to be weaker in tension than advertised: https://www.sciencedirect.com/science/article/abs/pii/S0950061819315247
I recall that the issue with screw anchors is that the threads grind into the boundary layer of concrete as they go in (so the threads will cut and bite), which weakens it slightly. This increases the chance that the anchor will encounter a "pull-out" failure before the larger (higher-capacity) volume of concrete fails through the stress cone.
Walkers
Well-known member
I use a Hilti drill and Hilti bits, it doesn’t get much better than that.I had a lot of problems with sleeve and wedge anchors until I purchased a good drill and started buying good drill bits. (I also throw them away when they start to get worn.) I no longer have any problems.
That being said, I personally do use screw anchors for most of my work. I like them in shear and for light tensile loads but don't use them for any heavy tensile loading. (Most epoxies are also "creep" and are bad under sustained tensile loading. Some posters on this site have used epoxy for their lifts and not checked for this important spec.)
The details on how to use these anchors are in engineering design guides, which are not freely available but here is a link to a scholarly article that can be purchased where a researcher tested screw anchors and found them to be weaker in tension than advertised: https://www.sciencedirect.com/science/article/abs/pii/S0950061819315247
I recall that the issue with screw anchors is that the threads grind into the boundary layer of concrete as they go in (so the threads will cut and bite), which weakens it slightly. This increases the chance that the anchor will encounter a "pull-out" failure before the larger (higher-capacity) volume of concrete fails through the stress cone.
wssix99
Well-known member
If your tools aren't doing the job correctly, how can you say that? The name on the side of the tool isn't enough. Even the low end Hilti is going to do a relatively poor job.I use a Hilti drill and Hilti bits, it doesn’t get much better than that.
IMO - Better to spend money on a more powerful "off brand" drill than a less capable "name brand" drill. (Unless there are other service, support, or accessory benefits that can be gotten.)
Walkers
Well-known member
I don't use low end anything.
Walkers
Well-known member
Some people are hard to please. I think I must have dated his sister back in college, fortunately it was short lived.There are "low end" Hilti products?
Thanks everyone for a good discussion.
Learned a bit, and hopefully shared some thoughts also.
Finally met with the concrete guy to discuss the project late yesterday.
Looks like the thickened section under the lift works well as long as you tie it in with rebar, and take it into account when you make your stress relieve cuts.
It will only be an extra couple of inches, but will allow longer fasteners, raising the retention strength, and will reduce the chance for a crack anywhere near or between the posts.
Learned a bit, and hopefully shared some thoughts also.
Finally met with the concrete guy to discuss the project late yesterday.
Looks like the thickened section under the lift works well as long as you tie it in with rebar, and take it into account when you make your stress relieve cuts.
It will only be an extra couple of inches, but will allow longer fasteners, raising the retention strength, and will reduce the chance for a crack anywhere near or between the posts.
Quite often I hear people saying that the engineers have totally got this. Supposedly they approved of the choice of concrete anchors and we should not try to second guess or improve things. From my experience of buying these things, I have come up with the conclusion that no engineer ever saw the anchor bolts or any components. I can't even prove intelligent design happened. Maybe at one time they designed something many generations ago. So, buy them under the assumption that you are the engineer in charge and do your own homework.I used the anchors supplied with the lift. The engineers did the thinking and included the anchoring system that best suited the situation. My lift is certified to 9000 lbs. and they were tested to 27,000 lbs. I have no reason to think that I am smarter making the decision about anchors than they are.
Mine had the anchor with the nut installed with the thread fully in the nut but not protruding, tapped into the hole. Then they were torqued to (I think, by memory) 100 foot lbs. with a torque wrench. Then a car was put on the lift, about a half dozen raise/lower cycles were done, and the anchors were torqued again. If an inch or more of threads was showing above the nut, the anchor was failing and it should not be used. Mine had a few threads showing. 20 years later, all is well.
Why would you deviate from what the factory engineered for the purpose? If you are a licensed professional engineer and you have done calculations to verify that another anchoring system will work, go ahead. I am not a licensed engineer. I don't want to be the dead guy squashed under a car with reports saying that the idiot installed his lift with anchors he thought would work better than the engineered system.
Just a little follow up.Thanks everyone for a good discussion.
Learned a bit, and hopefully shared some thoughts also.
Finally met with the concrete guy to discuss the project late yesterday.
Looks like the thickened section under the lift works well as long as you tie it in with rebar, and take it into account when you make your stress relieve cuts.
It will only be an extra couple of inches, but will allow longer fasteners, raising the retention strength, and will reduce the chance for a crack anywhere near or between the posts.
Glad I added a little extra depth, as it made setting the anchors less stressfull.
Wish I added more depth because about 1/2 the holes blew through the bottom.
P.S. a good concrete guy helps a lot as I have zero cracks other than cut relief lines.
So if I have never put an anchor in concrete before, I should still do what I think is better instead of the engineer that designed the lift and says what should work?Quite often I hear people saying that the engineers have totally got this. Supposedly they approved of the choice of concrete anchors and we should not try to second guess or improve things. From my experience of buying these things, I have come up with the conclusion that no engineer ever saw the anchor bolts or any components. I can't even prove intelligent design happened. Maybe at one time they designed something many generations ago. So, buy them under the assumption that you are the engineer in charge and do your own homework.
How do I know the guy that designed the anchors knows what he’s doing?
How do I know the guy at the concrete plant that mixes everything to make concrete that he knows what he’s doing?
Last edited:
wssix99
Well-known member
If you don't understand how concrete anchors work with a lift, we can help you. Please tell us what doesn't make sense. (There are also some good threads on this site with details.) The people who design the lift and write the specifications definitely are doing things on purpose.Quite often I hear people saying that the engineers have totally got this. Supposedly they approved of the choice of concrete anchors and we should not try to second guess or improve things. From my experience of buying these things, I have come up with the conclusion that no engineer ever saw the anchor bolts or any components. I can't even prove intelligent design happened. Maybe at one time they designed something many generations ago. So, buy them under the assumption that you are the engineer in charge and do your own homework.
By the thinking you presented, we should all stick stuff up our own butts and do our own colonoscopy if we don't understand why our doctors do things a certain way. (Hopefully we'd take the time to have a conversation, first.)
The people who design the lift and write the specifications definitely are doing things on purpose.
By the thinking you presented, we should all stick stuff up our own butts and do our own colonoscopy if we don't understand why our doctors do things a certain way. (Hopefully we'd take the time to have a conversation, first.)
I agree with you.
It is kinda like the road and highway construction near me, the wife reads on face book peoples comments about how the state is doing the highway construction wrong and how they should do it. Like the cashier job they have at walmart makes them better at designing bridges.
I'm not a fan of drilling through the concrete. Look up the install instructions from most anchor suppliers, they recommend against it for two reasons. It increases the chance moisture can come up from the ground and corrode the anchor and it weakens the concrete.
Mine is done with rated anchors, I bought Ramset ones vs generic home improvement store off brand for piece of mind.
Mine is done with rated anchors, I bought Ramset ones vs generic home improvement store off brand for piece of mind.
I'm not a fan of drilling through the concrete. Look up the install instructions from most anchor suppliers, they recommend against it for two reasons. It increases the chance moisture can come up from the ground and corrode the anchor and it weakens the concrete.
Mine is done with rated anchors, I bought Ramset ones vs generic home improvement store off brand for piece of mind.
Im not a fan of drilling straight through the concrete either but it also works both ways that if it's not drilled through the hole better be sealed well around the stud from the top or else when water gets in there it has no place to go which will also corrode it.
I don't know what instructions or specifications you got with your lift, but most do not come with specifications or even instructions. If they do give them, they don't even belong to the lift or even the type of lift you actually have. I don't have chains, air lines, gears or chains but the supposed specifications showed them. You can't use any information about torque, size or strength of fasteners that are given. I guess I have a different relationship with my enterologist as you because I would certainly do my own colonoscopys if I could. My comment still stands as pertinent. It is quite random as to what bolts they send with the lifts. Heck I got 30 pounds of steel shafts with mine. They look expensive, but they don't go with the lift. And they tried to contact someone about where the extra parts go. No one knew to even say that they didn't go with the lift. Not confidence building. I got a Tuxedo 11,000 pound 2 post, an American brand. I called for details and to speak to an engineer, or someone who was in the know at least, from several companies. The walk away is that the engineers don't even exist. Everything is substituted from the original design which probably is itself just an adaptation of something someone else did.If you don't understand how concrete anchors work with a lift, we can help you. Please tell us what doesn't make sense. (There are also some good threads on this site with details.) The people who design the lift and write the specifications definitely are doing things on purpose.
By the thinking you presented, we should all stick stuff up our own butts and do our own colonoscopy if we don't understand why our doctors do things a certain way. (Hopefully we'd take the time to have a conversation, first.)
I am using the HIS internally threaded anchors from Hilti. If you have to buy these, I will have a couple extra. They come in boxes of five. Ten cost about 450 bucks. With four bolts, a drill bit and twelve 2.5" bolts and several tubes of epoxy you are looking at six hundred bucks to bolt them down in a movable way. I have one question though. How do we get good centering of the anchors if we have to drill through a 3/4" hole in the base plate? If we have to do one or two at a time, do we drill and bolt all at once with only 3 minutes set time? With the supplied anchors you just drill a 3/4" hole and set them one at a time so they line up. The hole is the same size as the anchors. My experience with setting poured in anchors and pre-drilling anchors gets you to a situation where they just don't line up. The Hilti anchors, (HAS) style, the bolt is 3/4 inches and the hole is 1 1/4". So, I think I will drill a 3/4" hole with a regular concrete bit and then bore them larger with a 1 1/4" core bit since they don't drift. My plan might be to make a baseplate spacer with the holes pre-drilled, but they will be the 1 1/4". The spacers will then go under the lift to get another 1" of lift. I just don't like the only 71" of clearance I bought. I will do a write up when I get done. Any body have Ideas on how to get perfect placement of the anchors? If I don't use a metal spacer, does anyone think a wooden template would guide a core bit of 1 1/4"? I have some time to think because I am in the process of raising the roof a couple feet and doing the garage door thing to get everything in there. My garage is about 9.5 feet tall, so I am installing a beam, 2x8 rafters, 2x6 ceiling joists and walls. I have to move hvac, lights and many, many electrical circuits. Changing the height of the space is twice as expensive as the lift. I'm trying to stay under 10,000. The lift is sitting outside right now.I used epoxy anchors with my MaxJax and no problems for the 10 years I had it. I have a new, (10K) lift and am going to see if Hilti will recommend some epoxy anchors.
I wrote the previous reply to someone who was asking about the Hilti anchors. I researched the topic until it was dead. I got em, but they will add about 800 bucks to your install. They use an 1 /14 hole, so you are getting twice the circumference for the epoxy to grip or adhere.
Oh, I have seen people on here torquing their epoxy anchors at the same tension as a wedge anchor. Wong and dangerous. The torque a wedge anchor uses to grab the walls of the hole is much more than what you would use to fasten an epoxy anchor. An epoxy anchors needs no torque to keep it in place. The low torque required is just to fasten the bolt. When the anchor is used, the torque should not be placing tension on the epoxy. The internally threaded sleeve should be set flush with the floor so it will jam against the bottom of the baseplate and not pull on the anchor just to stay in place. So, about 45 lbs of torque is all you would need. It is a 3/4" bolt, so there will not even be a tenth of a millimeter of stretch.
Oh, I have seen people on here torquing their epoxy anchors at the same tension as a wedge anchor. Wong and dangerous. The torque a wedge anchor uses to grab the walls of the hole is much more than what you would use to fasten an epoxy anchor. An epoxy anchors needs no torque to keep it in place. The low torque required is just to fasten the bolt. When the anchor is used, the torque should not be placing tension on the epoxy. The internally threaded sleeve should be set flush with the floor so it will jam against the bottom of the baseplate and not pull on the anchor just to stay in place. So, about 45 lbs of torque is all you would need. It is a 3/4" bolt, so there will not even be a tenth of a millimeter of stretch.
You don't. That's the reason I made the comment. I know the concrete guys and I can test the concrete if I want. I have tested a lot of concrete for highway construction. You know, the guy who makes all those holes in brand new highways. I had a lot to do with figuring out what happened to the Hyatt Regency collapse and the Kemper Arena failure. Bolts aren't just bolts and concrete isn't just concrete. I read the Hilti application specs and they give the Kilopascals of force the epoxy can take, but not the metallurgy. Hilti can't give the tension force on the anchor itself, just the epoxy because bolts, not anchors have a tension rating. The lift does not give tension specifications that would be required and there is no one to say what they are. I can do some load calculations myself and I know the wedge anchors can't give the same holding tension as the chemical anchors. How many pounds of tension can a standard wedge anchor hold? How many pounds of tension can a 1 1/4" chemical anchor hold? Those are the questions I would like multiple answers for.So if I have never put an anchor in concrete before, I should still do what I think is better instead of the engineer that designed the lift and says what should work?
How do I know the guy that designed the anchors knows what he’s doing?
How do I know the guy at the concrete plant that mixes everything to make concrete that he knows what he’s doing?
You don't. That's the reason I made the comment. I know the concrete guys and I can test the concrete if I want. I have tested a lot of concrete for highway construction. You know, the guy who makes all those holes in brand new highways. I had a lot to do with figuring out what happened to the Hyatt Regency collapse and the Kemper Arena failure. Bolts aren't just bolts and concrete isn't just concrete. I read the Hilti application specs and they give the Kilopascals of force the epoxy can take, but not the metallurgy. Hilti can't give the tension force on the anchor itself, just the epoxy because bolts, not anchors have a tension rating. The lift does not give tension specifications that would be required and there is no one to say what they are. I can do some load calculations myself and I know the wedge anchors can't give the same holding tension as the chemical anchors. How many pounds of tension can a standard wedge anchor hold? How many pounds of tension can a 1 1/4" chemical anchor hold? Those are the questions I would like multiple answers for.
Over the years of hanging fire sprinkler pipe I’m sure I put in a few thousand 1/2” and 3/8” anchors, so I don’t have a problem putting anchors in but somebody that never has they just have to trust what they read in the directions of whatever they are trying to anchor.
dave*99
Well-known member
Interesting approach to waking up a 5 year old thread. I choose not to do my own colonoscopy. I prefer to stay away from A-holes.
My new lift (GrandPrix GP-10C), bought from Bendpak, does have instructions for installing the wedge anchors. As for drilling the holes, it says "Using the baseplates as guides, drill each hole 4" deep using a carbide bit of same diameters as the anchor (3/4"). They also say "do not drill all of the way through the concrete". Hilti agreed that the carbon steel HIT-Z 3/4" x 6 1/2" #2149587 anchors are sufficient for this application when used with the HIT-HY 200-R V3 adhesive (epoxy). Cost-wise, the anchors will be around $250 for (12) anchors and another $120 for 2 tubes (11.2 oz ea) of the epoxy. A Hilti epoxy dispensing gun is also needed, but numerous used ones are available on fleabay for ~ $50 - $60. So a little over $400 for a piece of mind. I found this video demonstrating the Hilti system.
Rusted Nut
Well-known member
Be aware the HITZ 3/4" will need a 7/8" diameter hole size. Hilti epoxy systems, IMO, are great.My new lift (GrandPrix GP-10C), bought from Bendpak, does have instructions for installing the wedge anchors. As for drilling the holes, it says "Using the baseplates as guides, drill each hole 4" deep using a carbide bit of same diameters as the anchor (3/4"). They also say "do not drill all of the way through the concrete". Hilti agreed that the carbon steel HIT-Z 3/4" x 6 1/2" #2149587 anchors are sufficient for this application when used with the HIT-HY 200-R V3 adhesive (epoxy). Cost-wise, the anchors will be around $250 for (12) anchors and another $120 for 2 tubes (11.2 oz ea) of the epoxy. A Hilti epoxy dispensing gun is also needed, but numerous used ones are available on fleabay for ~ $50 - $60. So a little over $400 for a piece of mind. I found this video demonstrating the Hilti system.
Thanks for the video.My new lift (GrandPrix GP-10C), bought from Bendpak, does have instructions for installing the wedge anchors. As for drilling the holes, it says "Using the baseplates as guides, drill each hole 4" deep using a carbide bit of same diameters as the anchor (3/4"). They also say "do not drill all of the way through the concrete". Hilti agreed that the carbon steel HIT-Z 3/4" x 6 1/2" #2149587 anchors are sufficient for this application when used with the HIT-HY 200-R V3 adhesive (epoxy). Cost-wise, the anchors will be around $250 for (12) anchors and another $120 for 2 tubes (11.2 oz ea) of the epoxy. A Hilti epoxy dispensing gun is also needed, but numerous used ones are available on fleabay for ~ $50 - $60. So a little over $400 for a piece of mind. I found this video demonstrating the Hilti system.
Yes, thanks.Be aware the HITZ 3/4" will need a 7/8" diameter hole size. Hilti epoxy systems, IMO, are great.
I don't want bolts sticking up from the floor if lift gets moved. That's the reason I am going with Hilti. The HIS Internally threaded anchors are the ones to use. They are just so darn expensive. I paid over 45 bucks a piece.Thanks for the video.