Welding rebar to J bolts

[River Runner]

Due to material costs I have elected to change my shop from wood framed to block. Currently it’s a 4’ high block stem wall that last year I wetset j bolt anchors in preparation for framing on. I just took delivery on my block and rebar and will begin the process of laying block the rest of the way up for my walls.
My original thought was I needed to drill and epoxy vertical rebar in the top bond beam course. Then I thought, wait, what if I just weld the rebar to my j bolts? They are set probably 4-6” in the course and stick up another 3-4”. I could place th e rebar next to the protruding anchor bolts and weld a bead on each side. Thoughts?

 

[Captain Spaulding]

Need to talk to a competent structural welder or engineer. Welding rebar is one of those odd things. Typical rebar doesn’t do well when welded. No big deal welding a piece to make a tool or handle, but in a structural application you want to do it right.

 

[Nthill93]

Not all rebar is weldable it needs to marked as such

 

[41plym]

You can weld rebar but you may experience cracking due to hard spots in some.
A706 rebar is considered weldable.

 

[Leaflessshadetree]

I wonder if welding (or possibly threading) a coupling nut to the rebar might be an option.

 

[manwithtools]

I wonder if welding (or possibly threading) a coupling nut to the rebar might be an option.

I was thinking the same thing, use a weldable class of rebar and weld a coupling nut to the rebar that matches the J-bolt thread.

 

[nadogail]

Add me to those who have doubts about welding rebar for structural purposes; yard art is one thing but depending on a weld to join rebar of questionable metallurgy is totally different.

 

[larry4406]

Coupling nut and threaded bar stock to extend your embeds?

 

[River Runner]

Good point about the weldable rebar, I forgot about that. Thanks for the ideas.

 

[matt_i]

I think if you tack welded them just to maintain position, the J-bolt is sill going to gain its pullout strength from the concrete surrounding it, just as if it was wet-placed just as the concrete was solidifying.

If you want more pullout resistance it should have been started earlier with long threaded rods that reach all the way thru and have large washer plates underneath.

 

[Walkers]

You are wasting your time. I could have drilled and epoxied all of your rebar in about a quarter the time of welding it, and there is no question about its legitimacy, or the quality of the weld. I just use the stuff in the caulking gun tubes from Simpson. If my boy starts right ahead of me with the hammer drill I can keep up with him as I blow out the holes, inject the epoxy, and insert the rebar. Done with a whole house in 15 minutes. The epoxy will rip out the concrete before it gives up too.

The placement of your J bolts probably isn’t ideal for block either, so you are likely to have to add some anyway.

 

[stillnostrebor]

You cannot fully develop a weldable rebar in tension with a welded on coupling nut. Epoxied rebar following good industry practice (as suggested above) is the best proven method in this case.

As a sidebar I concur that you need A706 bar if you are going to be welding it. We use it in weldments for concrete connection all the time, so it is accepted practice to do A706 rebar to plate welding.

 

[stevied916]

I agree with drill and epoxy. This is an accepted method when tying new concrete into existing concrete.

STRUCTURE magazine | Post-Installed Reinforcement

www.structuremag.org

 

[jrsavoie]

You are wasting your time. I could have drilled and epoxied all of your rebar in about a quarter the time of welding it, and there is no question about its legitimacy, or the quality of the weld. I just use the stuff in the caulking gun tubes from Simpson. If my boy starts right ahead of me with the hammer drill I can keep up with him as I blow out the holes, inject the epoxy, and insert the rebar. Done with a whole house in 15 minutes. The epoxy will rip out the concrete before it gives up too.

The placement of your J bolts probably isn’t ideal for block either, so you are likely to have to add some anyway.

I had a guy helping that thought he would cut a fat hog in the ****. He drilled all the holes, blew them all out and then put the epoxy in every hole.. He got 2 rebar put in.

I reminded him there was a reason I told him to epoxy and install rebar one at a time.

I am not familiar with the Simpson product. Do you have a link?

I always used the double barrel tubes from Hilti or Fastenal

 

[Walkers]

I had a guy helping that thought he would cut a fat hog in the ****. He drilled all the holes, blew them all out and then put the epoxy in every hole.. He got 2 rebar put in.

I reminded him there was a reason I told him to epoxy and install rebar one at a time.

I am not familiar with the Simpson product. Do you have a link?

I always used the double barrel tubes from Hilti or Fastenal

I had similar learning experiences when I first started playing with epoxy 15 years ago.

I have attached a picture. Looks like it is a Sika product thatI am using not the Simpson stuff. I used to use the double barrel stuff, then they changed the gun and wanted another couple hundred for a new gun…

Then the single tube stuff came out. I have been very happy with it. Sometimes I need to epoxy one or two fasteners that the substrate was poor. With the single tubes I am not wasting as much if I donkt use it again for a month. The single tubes are $20 for a single tube or $60 for a case.
I have left the nozzle on for as much as a month, take it off, do some minor excavation of hardened stuff, put a new nozzle on and used the rest of a tube. Dry time is very quick, so not a lot of monkeying around holding things in place.

I use several other different Sika products and am very impressed with the quality of their products.

 

[River Runner]

I decided I’ll just drill and epoxy, I already have the epoxy anyhow. I’ve never done this for vertical reinforcement just when tying a slab together or against a stem wall. Is 6” of depth generally enough?

 

[jrsavoie]

I decided I’ll just drill and epoxy, I already have the epoxy anyhow. I’ve never done this for vertical reinforcement just when tying a slab together or against a stem wall. Is 6” of depth generally enough?

That is all we ever went.