mohawk install info (from wej-it anchors tech support)

[Piper]

So I installed my mohawk system 1 a few months back. I started thinking about the monthly, annual maintenance stuff. As an aside, the only thing I can see as variable with an install of this type of lift is the floor. The lift is bombproof, assuming you do what it is intended to do. Anyway, I contacted Wej-it anchors to see what the re-torque procedure would be for the fasteners which hold the posts to the floor. The install manual states very clearly to install the fasteners and hand torque to 70 ft-lbs. I wondered if I should be backing them off a bit and then re-torquing back to 70, just make sure they still click at 70 etc.

The guy at tech support at wej-it asked what type of lift, referenced some book or something on his end, then proceeds to tell me that they're 3/4" x 6" wej-its, all very thorough. He then says that the fasteners should be torqued to 85 ft-lbs, not 70 ft-lbs as indicated in the manual. He says that Mohawk suggests/indicates 70, but wej-it suggests 85. Hmm, that's a difference of 17%, not insignificant by any means. He then indicated that after a week of having them torqued to the 85, to go and recheck at 1/2 that value (say 42 ft-lbs). He said the week is for the concrete to actually "get used to the compression". At the 1/2 torque the fastener shouldn't "budge" according to the fellow. He suggested that, testing whenever necessary, at the 1/2 torque would be fine.

So, I post this food for thought as I know others have raised concerns when you've got 7000 lbs of steel over your head.

Piper

 

[Busted_Knuckles]

They do loosen up with time, I bought my first Mohawk mid to late 80s. I didn't have an interval, but would re-tighten them a couple times a year. Ive never put a torque wrench to them, I'm sure Ive tightened them to over 100 ft pounds, probably closer to 150 ft lbs.

 

[911garage]

Piper,

The guys at wej-it are the greatest I have had questions on other construction conditions and they are so much better than red head in the tech dept. Thanks for the info.

 

[walrus]

So I installed my mohawk system 1 a few months back. I started thinking about the monthly, annual maintenance stuff. As an aside, the only thing I can see as variable with an install of this type of lift is the floor. The lift is bombproof, assuming you do what it is intended to do. Anyway, I contacted Wej-it anchors to see what the re-torque procedure would be for the fasteners which hold the posts to the floor. The install manual states very clearly to install the fasteners and hand torque to 70 ft-lbs. I wondered if I should be backing them off a bit and then re-torquing back to 70, just make sure they still click at 70 etc.

The guy at tech support at wej-it asked what type of lift, referenced some book or something on his end, then proceeds to tell me that they're 3/4" x 6" wej-its, all very thorough. He then says that the fasteners should be torqued to 85 ft-lbs, not 70 ft-lbs as indicated in the manual. He says that Mohawk suggests/indicates 70, but wej-it suggests 85. Hmm, that's a difference of 17%, not insignificant by any means. He then indicated that after a week of having them torqued to the 85, to go and recheck at 1/2 that value (say 42 ft-lbs). He said the week is for the concrete to actually "get used to the compression". At the 1/2 torque the fastener shouldn't "budge" according to the fellow. He suggested that, testing whenever necessary, at the 1/2 torque would be fine.

So, I post this food for thought as I know others have raised concerns when you've got 7000 lbs of steel over your head.

Piper

Did the anchors come with the lift? Is so Mohawk tests their lifts with Mohawks specs.They get their listings using their instructions not Wejits. Therefore I'd think Mohawks specs supercede anything Wejit says.

 

[GeorgiaHybrid]

Walrus,

I would trust Mohawk for the lift but when it comes to concrete anchors, I'm going to trust the guys that make them. We have used Wej-it, Red Head and Hilti anchors on a lot of jobs over the years and when used and tightened per specs, we have never had one fail as long as the concrete was poured to spec.

 

[brownbagg]

the problem with keep checking the torque, you can over tighten and start to crack the concrete. Ii always use a feeler gauge and see if you can slip between the washer to see if it came loose.

 

[WNYflyer]

I believe a Wej-it is a brand of what is called an "expansion anchor" You have to be careful using them on equipment and situations where you can have vibrations. Vibration, etc can cause them to loosen up over time. How much vibration ? ahhh.... that is the "gray" area. Many times we have specified expansion anchors but also added epoxy grout to the hole to take care of any possible loosening due to vibration (conveyors, pump bases, etc). I would always go by the bolt manufacturers torque recommendations (get installation instructions), it's their product and they are the experts. Of course the bolt is only as good as the concrete it is attaching to.

 

[ebfabman]

Thats why I'm fabricating receiver brackets with threaded sleeves imbedded in about 12 inches of concrete so the lift can be bolted to the floor

 

[walrus]

Walrus,

I would trust Mohawk for the lift but when it comes to concrete anchors, I'm going to trust the guys that make them. We have used Wej-it, Red Head and Hilti anchors on a lot of jobs over the years and when used and tightened per specs, we have never had one fail as long as the concrete was poured to spec.

So if a Lawyer asks, are you going to say you ignored manufacturers instructions? Hows that going to work out for you? The instructions are written in a specific way for a reason. I assume its the way Mohawk got their listing.

 

[wendell]

So I installed my mohawk system 1 a few months back. I started thinking about the monthly, annual maintenance stuff. As an aside, the only thing I can see as variable with an install of this type of lift is the floor. The lift is bombproof, assuming you do what it is intended to do. Anyway, I contacted Wej-it anchors to see what the re-torque procedure would be for the fasteners which hold the posts to the floor. The install manual states very clearly to install the fasteners and hand torque to 70 ft-lbs. I wondered if I should be backing them off a bit and then re-torquing back to 70, just make sure they still click at 70 etc.

The guy at tech support at wej-it asked what type of lift, referenced some book or something on his end, then proceeds to tell me that they're 3/4" x 6" wej-its, all very thorough. He then says that the fasteners should be torqued to 85 ft-lbs, not 70 ft-lbs as indicated in the manual. He says that Mohawk suggests/indicates 70, but wej-it suggests 85. Hmm, that's a difference of 17%, not insignificant by any means. He then indicated that after a week of having them torqued to the 85, to go and recheck at 1/2 that value (say 42 ft-lbs). He said the week is for the concrete to actually "get used to the compression". At the 1/2 torque the fastener shouldn't "budge" according to the fellow. He suggested that, testing whenever necessary, at the 1/2 torque would be fine.

So, I post this food for thought as I know others have raised concerns when you've got 7000 lbs of steel over your head.

Piper

I'd do what the Wej-it guy tells you to do just like I did what the Red Head guy told me to do. I also would fiddlefcuk around with backing them off again and again. You're not trying to stretch con rod bolts. You've seated a fasterner into concrete. It's there. Let it stay there and do it's job.

 

[trloh]

These are wedge anchors. The initial torque is there to set the wedge. If an anchor is going to try and pull out of concrete it is going to wedge tighter. Only if the concrete has some material flaw would it make it out of the concrete.

If you think that the torque placed on the nut holds the anchor in the concrete then just remove the nut and do whatever you want to try and pull the anchor. It ain't comin' out.

 

[GeorgiaHybrid]

So if a Lawyer asks, are you going to say you ignored manufacturers instructions? Hows that going to work out for you? The instructions are written in a specific way for a reason. I assume its the way Mohawk got their listing.

I will tell the lawyer that I followed the manufacturers instructions to the letter for installing the bolts. I will also tell him that I followed the manufacturers instructions to the letter for operating the lift.

The manufacturer of the item being installed is the expert that should be followed if you have conflicting instructions. They know their product and the usage of that product better than anyone else.