A36 vs. B7 Anchor Bolts

[clarkoh]

I am erecting a 60x100 steel building. The structural engineer specified A36 anchor bolts, embedded in the reinforced concrete piers. I have 2 different anchor assemblies. I had no trouble getting the A36 "L" shaped bolts in 18". I have some shorter (8") piers where I will have to drill the footer and epoxy in studs. We messed up and did not insert the anchor bolts into the footers where the foundation is only a single course of CMU's. I have found a B7 alloy threaded rod which I plan to use with the epoxy. Once these are in place, we will pour the floor and fill the single course of block, embedding the required 12" in concrete. In addition, a nut and washer will be tack welded to the submerged end of the stud.
Are there any potential side effects to using the much stronger B7 material, as opposed to the A36? I tried to ask the structural engineer, but he does not respond to my voice messages or emails. I guess once the check clears the bank, I am on my own!

 

[unclesyd]

B-7 all thread is used for anchors on many jobs.

One caveat is if you are going to tack the nut on the embedded end of the rod make the tack on bottom of the rod and nut, not on the inside of the nut. It is normally not considered a good practice to weld on B-7 studs. By weld on the bottom there is no influence on the strength of the threaded rod.

 

[clarkoh]

My plan is to tack the nuts with 4 inches of rod extending through. This length will be epoxied into the footer. When the floor is poured, the additional 8 inches of rod (one CMU) will become encased. The tack weld would be on the non or should I say less tensioned part of each rod. Thanks for the response.

Flying Hammer LLC a hot rod fabrication facility in Lincolnton, NC

http://www.flyinghammerllc.com

 

[Ron]

clarkoh...use a proprietary epoxy anchor bolt with rated loads. Your system will have to be proved, most likely, to a building official. They won't be much different, just that theirs have gone through testing and are generally approved.

I would suggest Hilti or Simpson...both have good systems with load ratings.

 

[clarkoh]

Thanks for the tip. The GC is aware of the implications. They generally stick with Hilti products. I have a Fastenal Store within 3 miles of the building site, so getting the right material is pretty convenient. The inspector was the one who suggested the epoxy system, rather than a drive anchor, like Red Head. Sometimes the inspectors can be helpful. In this case, we have a good one!

Flying Hammer LLC a hot rod fabrication facility in Lincolnton, NC

http://www.flyinghammerllc.com