Epoxy anchor bolts 1

[greencircle]

Hi Guys,

I need to know your opinion about using epoxying anchor bolts.

The situation is a we have a 20ft tall light pole with a cast base. The base has 4 holes on 12.5in bolt circle for anchors. Now when we want to install the poles, we notice that anchors bolts on the ground are on a smaller bolt circle (11.0in).

Since the difference between the BCs is large, thinking of drilling and expoxing 4 new bolts @ 45degs.
Anyone has such experience? epoxy strength?

Is this allowed per Aashto?

Thanks

 

[bridgebuster]

The AASHTO Sign & Luminaire Manual doesn't address post-installed anchors; LRFD specs don't mention anything either. You have to follow ACI318 Appendix D; this is normal on projects governed by the AASHTO specs.

 

[racookpe1978]

1. Do NOT re-drill the cast base. How many bolts in the casting, and what diameter?
2. If cast into concrete, the "bad bolt circle" is 11.0 BCD, right.

There are several things you can do - some are cheaper and easier than others.


Required BCD is 12.5, but what diameter bolts? How many bolts in the bad BCD, and what diameter?
How were the bad bolts inserted in the concrete? Or were they cast inplace with a bend or baseplate on the embedded threaded rod?

 

[greencircle]

L shaped anchor rods. Thread size 3/4 "
Placed 4 rods on 11" BC & poured concrete to cure.

 

[racookpe1978]

OK. With only 4x original rods, its easier.

Cut those off, a little below concrete surface if possible if the casting is flush cast, and either epoxy-coat (to prevent future rust) or galvanize thoroughly. If the casting has room, cut them off higher, then coat the stub.

"Rotate" the casting 45 degrees, and drill and epoxy in as deep as possible into the concrete the new bolts. Rotate the casting to fit the new embedded bolts, then install the post.

IF - and it sometimes happens - the post is a single piece arm with the casting, show the drawing of the post and casting. There are some other options.

But, 4 new bolts on a 12 inch BCD will not cause interference pull-out problems with 4 bolts left in the original concrete, as long as the original bolts have no tension stress on them. They (the original bolts) act kind of like "vertical rebar" in the concrete, which is why you do have to be careful there is no corrosion problems caused by leaving the original bolts in place.