Wedge anchor depth in concrete

[Raul.P]

Hi

I started to install a bendpak two-post lift and I made a little mistake drilling holes for 2 wedge anchors. The depth had to be 4 inches in concrete but I did not consider the thickness of the base plate of the column correctly and the holes are now actually about 3.4 inch deep and I already tapped in the achors so I can not get them out. Those are the most outward side anchors. The lift has an overhead beam assembly so I think the pull out tension to the bolts should not be as much as for the lift without the overhead beam. What do you think is it going to be a problem? The other anchors I am going to install as deeply as possible.

 

[matt_i]

How much thread is sticking up currently, above the hand-tightened nut?

 

[Raul.P]

How much thread is sticking up currently, above the hand-tightened nut?

A lot. I wanted that there will be enough room if the column needs shimming or smth. I did not used the bolts that came with the lift. I bought a little longer bolts .

 

[PoorOwner]

what is the minimum embedment specified for your anchors?

 

[Chilliwack Murray]

What is the minimum depth listed on the anchor spec sheet?

That’s a risky thing to play with even though there’s probably significant safety margin in all the specs it’s not something I’d chance personally. When anchors fail due to insufficient depth it is sudden and absolute, with the top layer of concrete going flying. I’ve seen this many times, they rarely just gently pull out.

Shift everything a few inches and start over is my vote. And drill the holes all the way through so you can drive a failed or damaged anchor through and put a replacement in. It’s not uncommon for them to pull up too far before they grab and set. When that happens you’re best to use a new anchor.

 

[Raul.P]

I have very thick pad so I can not drill through. What about those who have 4 inch thick pad that is sufficient according to bendpak. Do they need to drill through or is it possible to mount a wedge without drilling through. If not then their hole depth should be near what I have now. I can not belive I made such a foolish mistake . My garage is very small and that was the sweet spot for the lift.

 

[Kaizen]

Drill all the way through so you can pound them through if they get messed up. Took me ten hours to get two of these spinners out. You should also shim it completely before installing the anchors.
If you did not set them see if you can work them out. Don’t cut any corners. Last thing I wanted was as I am being crushed to death after it falls in me was to know I am at fault for being lazy.


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[PoorOwner]

It would be very hard to remove them because as you try to pry them it would have the same action as tightening it and expanding the wedge. Unless the hole is quite sloppily large.

Just asking if you meet the minimum depth requirement then drilling deeper usually does not increase the strength that much more.

 

[matt_i]

A lot. I wanted that there will be enough room if the column needs shimming or smth. I did not used the bolts that came with the lift. I bought a little longer bolts .

Unfortunately "a lot" doesn't define anything here. Can you give a measurement? Or post a picture would be fine.

Normally I put the nut on a wedge anchor at the full thickness of the nut. Then expect to seat that nut+washer on the steel foot of whatever is being anchored.

Don't worry if this is incorrect. With some violence and persistence you can drill out the steel stud and then begin to drill the hole in the concrete deeper. There's always an epoxied anchor as a replacement which is superior performing in every way to a wedge anchor except for the cost and time.

 

[Kaizen]

Also make sure you are using an sds drill not a regular hammer drill


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[tonyciambrone]

Not so sure this is a big deal or you made the mistake you think you did.

The 4" Minimum Concrete pad thickness is probably from Bendpak's specifications.

What others above have asked is what is the minimum depth embedded for the wedge anchors you used. If it is less than the depth you drilled your holes (I.E 3.25" embedded or 3.0" embedded) for the wedge anchors, and your pad is thicker than the 4" Bendpak requires, I don't see a reason to start over.

If the anchors you used need to be embedded further- let's say 5", then you have a problem that would need to be addressed. At that point, other people know a lot more than I do about how to proceed.

 

[RivennHewn]

What brand anchors did you use?

 

[SGKent]

there are some videos out there that use this same principle to remove a standard type wedge bolt where the bolt and wedges are one assembly, made of steel, or steel and lead. There are some other type wedge bolts with hardened steel wedges that have nubs on them that I don't think it would work. https://vimeo.com/124880350

 

[Raul.P]

What brand anchors did you use?

https://www.wuerth.com/

The overall lenght is approximately 6 inches of those achors. I thought that I should leave more thread to protrude form the nut because of possible shimming and bendpak also has a hoist for adapters that is later installed under those nuts. I wanted the holes 4 inch deep in concrete as bendpak recommends but I miscalculated and the hole ended up not so deep. I did not watched out for minimum embedment depth for those new anchors because I thought there should be no big difference with the achors which were originally with the lift as they almost the same size - 3/4 inch original ( 19 mm ) vs 20mm new .

 

[jeepxj]

Drill all the way through so you can pound them through if they get messed up. Took me ten hours to get two of these spinners out. You should also shim it completely before installing the anchors.
If you did not set them see if you can work them out. Don’t cut any corners. Last thing I wanted was as I am being crushed to death after it falls in me was to know I am at fault for being lazy.


Sent from my iPhone using Tapatalk

this is the pro tip. drill all the way thru every time on wedges

 

[jeepxj]

Drill all the way through so you can pound them through if they get messed up. Took me ten hours to get two of these spinners out. You should also shim it completely before installing the anchors.
If you did not set them see if you can work them out. Don’t cut any corners. Last thing I wanted was as I am being crushed to death after it falls in me was to know I am at fault for being lazy.


Sent from my iPhone using Tapatalk

this is the pro tip. drill all the way thru every time on wedges

 

[RivennHewn]

I’d contact bendpak to get the spec on pull out force, then compare with your anchors.

You may have to contact your manufacturer to get info on the actual depth as installed.

If they meet bendpaks spec as is, you go with them as is.

They may need to know the PSI rating of the concrete you are installing them in.

Be sure to torque them to spec as well.

 

[RivennHewn]

this is the pro tip. drill all the way thru every time on wedges

Drilling clear thru a slab can cause problems if you have moisture conditions on your site and you penetrate your vapor barrier.

Using an anchor like the Hilti TZ, can get the spec’d ratings with a shorter anchor that doesn’t penetrate all the way through.

 

[finn]

If you feel yo absolutely must remove the anchors, consider using epoxy potted anchors and you can probably salvage the existing holes.

The wedge anchors will probably come out if you finesse the wedge rather than attempt a direct pull. I got one out without damaging the anchor or the drilled hole.

 

[wssix99]

there are some videos out there that use this same principle to remove a standard type wedge bolt where the bolt and wedges are one assembly, made of steel, or steel and lead. There are some other type wedge bolts with hardened steel wedges that have nubs on them that I don't think it would work. https://vimeo.com/124880350

This method should be fine for this particular situation and problem. Spinning the bolt may chew up the hole a bit, but after it's out, the hole will need to be extended and the new bolt will bit in that clean extension - so all should be good.

 

[Raul.P]

Ok, I am going to try to get them out with the method shown in the videos. I found a metal worker who makes a special piece that screws both to the anchor and to the sds adaptor. I do not have a hydraulic puller but I think with a lot of rotating and shifting the bolt up and down with a drill I should get it out finally. Then I am going to buy 7 inch wedges and this time I am going to drill as much as needed .

 

[firebirdparts]

That puller is pretty expensive, but I guess anything you can pull with would work.

 

[gmwelder86]

Get yourself a rebar eater. Cut anchor as short as you can with a cut off wheel on grinder and proceed to drill anchor out. Drilled out 3/4 hilti wedge anchors like this caused by same issue at work. It ***** buts it’s not impossible. Should be able to drill out in not much time.

 

[Raul.P]

I got one out. I moved it up and down while rotating till the wedge and cone wore so much out that it came out. In the middle of this process I tried to pull it out many times using a nut and spacers but it did not move.