Replacement Anchors for 2 Post Lift

[Homewrecker]

I had my 2 post lift installed in April. The installers used 3/4" X 6 1/2" wedge anchors that came with the lift and are most likely made in China.
I also had them install a base extension kit:



The floor is 6" thick and each post has a total of 13 (yes that's alot lol) of anchors installed. The monthly re-torque value is 110 ft-lbs. The first time I torqued them right after installation they were all around 80 ft-lbs but that is because the installers left the torque wrench at the shop. I torqued them all to 110 ft-lbs with no issue.

Each month I've re-torqued them (4 times so far) some of them still take torque. The first time didn't bother me so much as I assumed things were still 'settling and stretching' but each subsequent time they still take some some torque. A few nuts started to move when the wrench reached 80 ft-lbs while others were higher up in torque. Some didn't move at all and kept their torque. I marked the top of each stud and nut with a 'witness mark' so I can track how much the nuts moved and to see if the actual anchor is spinning in the hole which it is not.

Each anchor that takes torque the nut moves about 1/8 of a turn or slightly more but definitely less than a 1/4 turn each time I do the re-torque. It doesn't seem like much but my concern is if this keeps happening with every re-torque some of the anchors may eventually pull all the way up. Some of the anchor points have shims installed and I was thinking they are perhaps still compressing (HDPE Shims) but some anchors that take torque do not have shims installed at the hole at all.

For the anchors that do take torque, I was thinking about hammering them down (holes were drilled through the slab) and installing new ones which brings up my question.

I was looking at getting some Wej-it Ankr-TITE 3/4" x 6 1/4 anchors like the one below


I'm by no means an engineer but the retention 'clip' looks alot larger and more robust than the standard anchors that came with the lift. I did
contact Wej-it and they said this anchor was suitable for lift installs.

I have a buddy that works for Hilti and he recommended the TZ2 Kwik Bolt Wedge Anchor:


I know Hilti is supposed to be the holy grail for this sort of thing but compared to the Wej-it it looks like it has a much smaller clip.

He also recommended the Kwik-X Dual Action Anchor saying it is similar to threaded rod with HY-200 adhesive but 5x faster to install and instant load.



Again, I'm not an expert but I don't think this Anchor would be the best choice since it does appear to be permanent. I've read another thread on here somewhere that discussed this anchor and it wasn't recommended. It's not available in the length I need anyway.

Although I can get a discount through my Buddy, I'm still inclined to go with the Wej-it one due to the size of the clip.

I will not consider a chemical anchor system right now until I've tried to replace the original wedge anchors. Since the holes are right through the floor Hilti has no comment on installing the epoxy anchors since they did not test that configuration. Not sure how to get the adhesive to stay in the hole anyway. If I do need to go this route at least I'll get an employee discount lol.

I may be overly paranoid in this case but I'd rather be safe and deal with this early on. Should I just keep torquing them in hopes they will eventually maintain the torque or just hammer down the problem ones now?

Looking for thoughts / recommendations.....

 

[jonesg]

I had my 2 post lift installed in April. The installers used 3/4" X 6 1/2" wedge anchors that came with the lift and are most likely made in China.
I also had them install a base extension kit:



The floor is 6" thick and each post has a total of 13 (yes that's alot lol) of anchors installed. The monthly re-torque value is 110 ft-lbs. The first time I torqued them right after installation they were all around 80 ft-lbs but that is because the installers left the torque wrench at the shop. I torqued them all to 110 ft-lbs with no issue.

Each month I've re-torqued them (4 times so far) some of them still take torque. The first time didn't bother me so much as I assumed things were still 'settling and stretching' but each subsequent time they still take some some torque. A few nuts started to move when the wrench reached 80 ft-lbs while others were higher up in torque. Some didn't move at all and kept their torque. I marked the top of each stud and nut with a 'witness mark' so I can track how much the nuts moved and to see if the actual anchor is spinning in the hole which it is not.

Each anchor that takes torque the nut moves about 1/8 of a turn or slightly more but definitely less than a 1/4 turn each time I do the re-torque. It doesn't seem like much but my concern is if this keeps happening with every re-torque some of the anchors may eventually pull all the way up. Some of the anchor points have shims installed and I was thinking they are perhaps still compressing (HDPE Shims) but some anchors that take torque do not have shims installed at the hole at all.

For the anchors that do take torque, I was thinking about hammering them down (holes were drilled through the slab) and installing new ones which brings up my question.

I was looking at getting some Wej-it Ankr-TITE 3/4" x 6 1/4 anchors like the one below


I'm by no means an engineer but the retention 'clip' looks alot larger and more robust than the standard anchors that came with the lift. I did
contact Wej-it and they said this anchor was suitable for lift installs.

I have a buddy that works for Hilti and he recommended the TZ2 Kwik Bolt Wedge Anchor:


I know Hilti is supposed to be the holy grail for this sort of thing but compared to the Wej-it it looks like it has a much smaller clip.

He also recommended the Kwik-X Dual Action Anchor saying it is similar to threaded rod with HY-200 adhesive but 5x faster to install and instant load.



Again, I'm not an expert but I don't think this Anchor would be the best choice since it does appear to be permanent. I've read another thread on here somewhere that discussed this anchor and it wasn't recommended. It's not available in the length I need anyway.

Although I can get a discount through my Buddy, I'm still inclined to go with the Wej-it one due to the size of the clip.

I will not consider a chemical anchor system right now until I've tried to replace the original wedge anchors. Since the holes are right through the floor Hilti has no comment on installing the epoxy anchors since they did not test that configuration. Not sure how to get the adhesive to stay in the hole anyway. If I do need to go this route at least I'll get an employee discount lol.

I may be overly paranoid in this case but I'd rather be safe and deal with this early on. Should I just keep torquing them in hopes they will eventually maintain the torque or just hammer down the problem ones now?

Looking for thoughts / recommendations.....

you can block the bottom of the hole with a wad of sliced bread kneaded into a clump of dough.


it might be more related to the condition of the concrete than the anchors.
I just poured 8 inch at 40K psi for mine last week.
I'll probably drill through like you did, i've over engineered everything else so far , might as well keep going.

 

[Homewrecker]

you can block the bottom of the hole with a wad of sliced bread kneaded into a clump of dough.


it might be more related to the condition of the concrete than the anchors.
I just poured 8 inch at 40K psi for mine last week.
I'll probably drill through like you did, i've over engineered everything else so far , might as well keep going.

That's a different way of filling the hole lol. I guess I could use some non-porous foam as well. But again, I'll deal with that if/when the time comes for chemical anchors.

The floor is 9 years old. It has zero cracks and the compressive strength is approx 4600 Psi.

 

[wssix99]

Should I just keep torquing them in hopes they will eventually maintain the torque?

For now, yes. This is why they tell you to check every month. 1/8 to 1/4 of a turn isn't a big deal. If this goes on for another 8 months, then it would be weird.

 

[finn]

I’m no expert, but I agree that it’s probably the surface of the concrete microyielding at the anchor interface rather than the anchor itself.

 

[22george]

When I installed my lift I scrapped the chinese anchors and bought good ones from Fastenal. My lift manufacturer recommended 4 inch thick concrete. I had 8 inch thick concrete poured. I bought 8 inch long anchors. I've had my lift about 10 years. Checking the torque, it has stayed at 150 lb-in.

 

[Homewrecker]

When I installed my lift I scrapped the chinese anchors and bought good ones from Fastenal. My lift manufacturer recommended 4 inch thick concrete. I had 8 inch thick concrete poured. I bought 8 inch long anchors. I've had my lift about 10 years. Checking the torque, it has stayed at 150 lb-in.

I was originally going to have the installers discard the included anchors and use ones that I would supply but I would not have been able to get them in time for the install appointment. They were booked up months in advance so I didn't want to wait months for another appointment.

Since the floor is 6 inches thick, I'm wondering if I should stick with 6 1/4" anchors or move up to 7". The minimum embedment depth figure would still be the same for both.

 

[BillK]

I just want to mention that checking torque by just putting the wrench on and trying it is not really accurate. Most fasteners will "stick" after being together for a while and the breakaway torque to get them moving again will be much more than the actual torque spec.

The way we retorque head bolts on engines is to do one bolt at a time. I will first loosen the bolt about 1/4 turn and then torque it to the correct torque. You would be surprised how many move a substantial amount when done that way.

Try it on one of your anchor bolts that you think is tight. Mark the bolt head before you loosen it so you can see if it really did need tightening.

 

[Daedalus]

I just poured 8 inch at 40K psi for mine last week.

That's some slab.

 

[nitroracer20]

I personally feel like your WAY overthinking this - looking at the amount of wedge anchors you have in there already.

Youll create more problems trying to replace w/ different wedge anchors.

Leave it ALONE! Who knows - you could be stretching the threads torquing them…

You wanna go nuts, get threaded rod from your buddy at hilti and epoxy in w/ HIT200.

 

[Homewrecker]

I just want to mention that checking torque by just putting the wrench on and trying it is not really accurate. Most fasteners will "stick" after being together for a while and the breakaway torque to get them moving again will be much more than the actual torque spec.

The way we retorque head bolts on engines is to do one bolt at a time. I will first loosen the bolt about 1/4 turn and then torque it to the correct torque. You would be surprised how many move a substantial amount when done that way.

Try it on one of your anchor bolts that you think is tight. Mark the bolt head before you loosen it so you can see if it really did need tightening.

The breakaway torque on some of the fasteners that move is around 80 ft-lbs which I then subsequently bring up to the prescribed 100 ft-lbs. Others don't move at all when I reach 100 ft-lbs; those I'm not concerned about even though they might be 'sticking' at 100 ft-lbs.

I won't mess with them and loosen them and re-torque. I read that doing so may cause problems when trying to re-tighten them due to the retaining shoulder being deformed etc or something like that anyway; not quite the same as a bolt threaded into an engine block.

 

[Rusted Nut]

What is the compressive strength of your concrete? How long did you wait after pouring to install the anchors? Do you have rebar at the anchors? If you installed the anchors only a few days after pouring, the concrete is still curing/shrinking. The ultimate strength of wedge anchors is very dependent on compressive strength of concrete, and a very accurate hole diameter in minimum 28 day concrete.

Very difficult to replace wedge anchors with other wedge anchors. You’ll damage the concrete removing the anchors. If you really feel the need to replace, you’ll have to go with epoxy. Give everything a month and see if things tighten up.

 

[Zeke]

I don't know a lot about anchors but a 6" anchor in 6" of concrete seems to place the wedge near the bottom surface. Why not have the wedge at a more shallow depth like 4 to 5 inches? More solid concrete to push against.

 

[Homewrecker]

What is the compressive strength of your concrete? How long did you wait after pouring to install the anchors? Do you have rebar at the anchors? If you installed the anchors only a few days after pouring, the concrete is still curing/shrinking. The ultimate strength of wedge anchors is very dependent on compressive strength of concrete, and a very accurate hole diameter in minimum 28 day concrete.

Very difficult to replace wedge anchors with other wedge anchors. You’ll damage the concrete removing the anchors. If you really feel the need to replace, you’ll have to go with epoxy. Give everything a month and see if things tighten up.

That's not the issue in this case. The floor was poured 10 years ago in anticipation of a lift install at some point. Compressive Strength is 32Mpa / ~4600 Psi. There was no rebar that was hit during drilling so the holes are clear after being visually checked.

If the holes are drilled right through the slab, which in this case they are, it's not difficult at all to replace the anchors by hammering them through and won't really damage anything. The installers had to hammer one down due to it being the incorrect length - it somehow made it into the box with the other anchors. Ironically the location where the one was hammered down the current anchor is not one of the ones that take torque.

I'll give it a few more months of re-torque and see how they behave and from there.

I don't know a lot about anchors but a 6" anchor in 6" of concrete seems to place the wedge near the bottom surface. Why not have the wedge at a more shallow depth like 4 to 5 inches? More solid concrete to push against.

That's not exactly how it works. The anchor would be 6 1/4" in total length including the threaded portion. You have to take into account the overall slab thickness, the minimum embedment depth specified by the manufacturer and the total thickness of the fixture being fastened.

So in the end after doing the math you'll only end up having maybe a total 3 1/4" - 4" embedded in the slab depending on the overall thickness of the fixture that is being fastened; in this case being the base plate thickness plus the shims, washer and nut. So going with a longer anchor will give you more length to exceed the minimum embedment depth (if your slab is thick enough to allow it) but you have to make sure not to go too deep to avoid the retention shoulder being past or too close to the bottom hole.

 

[Zeke]

I didn't ask what length to use. I asked where the wedge should be WRT to the slab thickness.

 

[Homewrecker]

I didn't ask what length to use. I asked where the wedge should be WRT to the slab thickness.

Wedge location depends on what the manufacturer states. Each length will have a minimum embedment depth for the 'wedge' to engage. For 6 1/4" Anchors for example, Wej-It states 3 1/4" depth whereas Hilti calls for 4" for the same size anchor. Since the current anchors were included with lift I have no idea what the minimum spec is but assume it would be similar to other anchors.

So If I wanted the 'wedge' to engage lower in the slab to around 5" a longer anchor may be required since I'll still need enough threads to protrude for the base plate, shims and hardware.

 

[Rusted Nut]

Well considering your slab has been there for ten years, I don’t think giving it another month is going to help. Hammer the wedge anchors down and out, re drill hole for epoxy size, and install.

 

[Homewrecker]

Well considering your slab has been there for ten years, I don’t think giving it another month is going to help. Hammer the wedge anchors down and out, re drill hole for epoxy size, and install.

The Anchors may finally 'settle' so that is why I'm going to go through few more months of re-torques; nothing to do with the age of the concrete in this case. Epoxy will be the last resort is this keeps happening,..........

 

[1984shovelhead]

hilti makes a system that utilizes epoxy that on the concrete side of it is coarsely threadEd to facilitate adhesion to epoxy and a machine thread on the other end.We used these in an overhead application to set threaded rod where some heavy *** electric conduit would hang.They were later tested with a hydraulic gizmo to pull them out.The concrete failed before the anchor /epoxy did.Remember I said the concrete was not a high strength pour.Point being this system by hilti I forget the trade name is serious stuff.But with all those anchors you got in there I think your

 

[Spud McGee]

The guys that installed mine said this sort of thing can happen as a result of using a dull bit or poor form while drilling the holes.
Either of those can cause the inside wall of the hole to not be uniform. Then the anchors have a harder time maintaining their clamp against the those uneven walls.