Concrete & Anchoring Question

[SJK2]

General question here, using "Wej-It Original" brand 10" anchors into 16" of 5000 psi cured concrete for a two-post lift install. Can "epoxy" be used also to deliver additional piece of mind in the holding power ?????.

tia,
Steve

 

[rburke65]

I wouldn'ty see where it could hurt....Maybe down the road if they should ever loosen, the epoxy would hinder you from tightening the bolts up again. You could call Mister "Wej-It Original" and ask, or I'm sure there will be other opinions to come.

 

[SJK2]

rburke65,

Thanks for the response, I do have a info request into "Wej-It" but being a holiday weekend thought more posters would see it here.........

 

[SJK2]

A bump for exposure........

Anyone have a thought??

 

[toxicz28]

I wouldn't. Wedge anchors need a tight fitting hole to work properly (3/4" hole for a 3/4" bolt), epoxy needs an extra 1/8" in hole diameter to provide enough space for it. You can't combine the two. And if you're going with 10" of embedment, wedge anchors alone would be more than enough.

 

[DaleK]

Epoxy between the floor and the bottom of the posts if you want. I wouldn't put any in the holes, same reason toxicz gave

 

[ddawg16]

I'm not doubting you guys.....but....

I just saw some work done by 'professionals'.....1/2" anchor bolts....with epoxy....They ran the anchor bolts in with the epoxy in the hole....pulled the bolts up to egage the wedge...wiped off the excess and let set.

I don't know if it's right or wrong...that is just what I saw....

 

[Buckled]

I wouldn't. Wedge anchors need a tight fitting hole to work properly (3/4" hole for a 3/4" bolt), epoxy needs an extra 1/8" in hole diameter to provide enough space for it. You can't combine the two. And if you're going with 10" of embedment, wedge anchors alone would be more than enough.

This is the correct answer. Epoxy anchors need a 1/16" - 1/8" space between the rod and the hole wall to properly adhere to both. Also, epoxy anchors are tested with all thread rods. Keying into the threads for the entire embedment depth is very important.

Wedge anchors aren't always threaded the entire length (some are). If you use epoxy in the hole with the wedge anchor you may end up getting very little added strength, if any at all.

I don't blame you for wanting to use epoxy, it's stronger, it will last longer, and often time it handles vibratory loads better than mechanical anchors. If you do decide to use epoxy anchors just go with all thread instead of the wedge bolts and make sure you clean out the hole using compressed air. Many use shop vacs, but compressed air works much better and is the recommended procedure.

You'll also want to measure the predrilled holes on the base of the lift. If you plan to drill the holes with the lift in place, your drill bit will have to go through the holes in the base. That will determine the maximum size of the bit you can use, which will in turn determine the maximum anchor rod size you can use. This still may be OK depending on the tension (pull out) strength that the lift manufacturer recommends. Epoxy anchors have higher tension loads than common wedge bolts, but if you have to step down the rod (compared to the wedge bolt diameter) size to use epoxy anchors you be losing some shear strength (load that is applied perpendicular to the anchor). With that in mind, I highly doubt your lift creates much of a shear load, so the higher you can get the tension load the better off you'll be.

As far as the vibratory loads go, check the epoxy manufacturers specs. Usually, but not always, the slow cure epoxies handle vibratory loads better than the fast cure.

Good luck with your install.

 

[SJK2]

Thanks all for your input, I think I will just use the bolts.............