Two Post getting installed tomorrow

[cthulu]

My RTP9 two post is getting installed tomorrow on the 11 inch thick slab that was poured for it.

I want to make sure they use the right bolts for the install, from what I understand they should go all the way through the slab. My concern is they will just use whatever the standard depth bolts for a 4in slab are.

My concerns valid? What should I make sure they do during the install?

 

[T_R]

11" is extreme overkill on the thickness. Mine is 5" for my 9k lift.

Anyway, the anchor bolts don't need to go all the way through the slab, but the holes do. Reason being if they don't set you need to be able to pound them all the way out the bottom into the dirt. They are going to need quite the drill bit to get through your slab, a normal 12" isn't going to make it with drilling through the baseplate.

 

[cthulu]

11" is extreme overkill on the thickness. Mine is 5" for my 9k lift.

It was put in after, we cut a 4ft by 15ft hole in the 2-3in existing slab and re-poured to the specs listed for mohawk two post lifts.

I tried calling them to explain that the slab is thick and I got brushed off.

 

[pattenp]

My only advise is to not let them set the anchors with an impact wrench. They should be hand torqued to specs.

 

[tonycastec]

There are concrete screws that are inserted using hand tools + epoxy. Look at the Simpson +titen bolt site? There are other brands.You need to be 100% accurate with the correct hole diameter.

 

[lakeroadster]

Don't recreate the wheel. Follow the manufacturer's specifications.

 

[67gto]

My Bendpak came with 4" anchor bolts. My garage floor is 11" - 12" thick. I went out and bought 10" anchors. I got the 12" SDS drill bit from Lowes. I used a Harbor Freight SDS hammer drill to drill the holes. Worked like a charm. 6 anchors for each post. I didn't go all the way through to the dirt. When I was tightening them, a couple on each post pulled up a few inches. I'm not worried about it though, as they are still 7" to 8" in the concrete. I used a torque wrench to hand tighten the bolts. The 10" anchors were not cheap, I paid over $100 for 12 of them.

 

[wssix99]

Don't recreate the wheel. Follow the manufacturer's specifications.

+1 Also, don't listen to advice you get on the internet that contradicts those specifications/instructions.

 

[cthulu]

+1 Also, don't listen to advice you get on the internet that contradicts those specifications/instructions.

Installers are putting it in with wedge anchors right now, noticed you have a ws6...here's mine after her yearly wash.

 

[firebirdparts]

Awsome trans am owners! I wish you the best to enjoy that lift. Mine is the best money I ever spent.

I actually asked the lift manufacturer about the bolts when I bought mine, and they said "put it in with the anchors we sent. That's what we tested it with."

 

[Ign]

The manufacturer is just trying to do a one-size-fits-all with-minimal-tools approach.

It doesn't take a genius to see that concrete cracks, chips and flakes and the wings on expansion anchors create very concentrated point loads. Epoxy fills the ENTIRE void and works its way into every little imperfection of your hole - like a filling in a tooth.

I cut the wings off my anchors, cut grooves around the circumference w an angle grinder so the epoxy had something to grab, and used Hilti 2-part epoxy. That was 2009. I'm not dead yet. Just had my CCLB 4x4 F350 on the lift for 2 weeks.

I'd say the anchors are holding.....

Don't be afraid of some independent thought mixed w some common sense (it's the latter that most lack)

 

[lakeroadster]

Common Sense: If you like epoxy better (as I do too) email or call the manufacturer of your lift and asked about epoxy. They likely have a specification they recommend for their lift.

Why? Sometimes they will change the required thickness of the concrete, due to minimum embedment length required by the epoxy manufacturer.

I did that with my Rotary lift, and they sent the following. Their concrete thickness spec. for mechanical anchors is 4-1/4", 5.1" with epoxy:

 

[wssix99]

Installers are putting it in with wedge anchors right now, noticed you have a ws6...here's mine after her yearly wash.

A+++ Excellent. A worthy recipient for your new lift!

 

[wssix99]

Common Sense: If you like epoxy better (as I do too) email or call the manufacturer of your lift and asked about epoxy. They likely have a specification they recommend for their lift.

If one is going to divert, this is the way to go. The manufacturer will have a Plan B - off label for instances where the mechanical anchors have issues.

In places where they will advise for epoxy, there will be a limited choice. Not all epoxies are the same, some epoxies are unsafe for this application. (look up "epoxy creep"), and epoxy can fail in a very scary way. (see below)

It doesn't take a genius to see that concrete cracks, chips and flakes and the wings on expansion anchors create very concentrated point loads. Epoxy fills the ENTIRE void and works its way into every little imperfection of your hole - like a filling in a tooth.

Most geniuses don't understand concrete, but an engineer who does know about it will tell you that these statements aren't correct with regard to this application:

Any anchor holds on to a "cone" of concrete and the concrete resists the pull-out forces along the surface of that stress cone. The mechanical anchors work because they only grab at the apex of that cone - which is the only place that attachment is actually needed.

With an epoxy anchor, only the epoxy at the bottom of the hole matters. (This is one of the big reasons why it is so important to get all the dust out!) When the epoxy at the bottom of the hole is bad or isn't there, epoxy higher up grabs - the cone gets smaller - and the holding power of the anchor/slab system is much less:

 

[Daedalus]

from what I understand they should go all the way through the slab.

I have never seen a wedge anchor instruction manual that says to drill through the slab. The last set I put in actually stated specifically to NOT drill through, I'm guessing because they don't want dirt and/or moisture getting in there. As stated, people do it to allow for easy removal. But the anchor manufacturer won't accept any responsibility for performance if you don't follow their instructions.

 

[alberto]

If one is going to divert, this is the way to go. The manufacturer will have a Plan B - off label for instances where the mechanical anchors have issues.

In places where they will advise for epoxy, there will be a limited choice. Not all epoxies are the same, some epoxies are unsafe for this application. (look up "epoxy creep"), and epoxy can fail in a very scary way. (see below)




Most geniuses don't understand concrete, but an engineer who does know about it will tell you that these statements aren't correct with regard to this application:

Any anchor holds on to a "cone" of concrete and the concrete resists the pull-out forces along the surface of that stress cone. The mechanical anchors work because they only grab at the apex of that cone - which is the only place that attachment is actually needed.

With an epoxy anchor, only the epoxy at the bottom of the hole matters. (This is one of the big reasons why it is so important to get all the dust out!) When the epoxy at the bottom of the hole is bad or isn't there, epoxy higher up grabs - the cone gets smaller - and the holding power of the anchor/slab system is much less:

Great Post.

 

[pinesdune]

Ditto, thanks for this post, hope to be installing my lift this weekend


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[sberry]

Everybody is "special" I am with the follow instruction crowd. No need to invent something at every turn.

 

[dykstra]

You guys will love your lifts! The best tool in my garage.

 

[Walter_TA]

The deep the anchor is set the more it will support. That is why longer is better. 10 inch bolts will support more than 4.

 

[lakeroadster]

The deep(er) the anchor is set the more it will support. That is why longer is better. 10 inch bolts will support more than 4.

If the concrete is of adequate thickness.. I know, seems like common sense, but it isn't quite as common as it used to be.

Increased depth = larger stress cone area.

Larger area at a given load = less stress -or- higher load capacity at a given stress.

wssix99 previous post in this thread does a great job of explaining and visualizing this.

 

[pinesdune]

My lifts up, just have to wire it in