Specifying high-capacity epoxy anchors via in-situ testing

[timothy.mha]

In continuation of previous posts:

https://www.eng-tips.com/viewthread.cfm?qid=420144

https://www.eng-tips.com/viewthread.cfm?qid=473250

After reading previous engineers' struggles with the inherently low capacities of post-installed epoxy anchors, here is a method that's worked for me:

I apply the appropriate ASD to LRFD conversion, multiply by omega, and simply require that the holdown be subject to a pull test. I annotate on the plans the required load for the test. The contractor then must hire a special inspection agency to go out there and perform the test. Plan reviewers are okay with this, and contractors seem to like this better than drilling through, especially if they've already done the holdowns differently without notifying the EOR (because why would they?).

I've seen reports from agencies where epoxied holdowns are passing tests in excess of 8,000lbs, so while the theoretical limits are extremely low, I'm finding that real life paints (unsurprisingly) a very different picture.

I've yet to have one fail, but I'm about to specify one for an 8" stemwall that needs to take 10,568lbs. I suspect this time it might not work, but I already gave the contractor various options, they shortened the shearwall in the field, so it is their risk to take. Needless to say, you need to warn the contractor that it's not guaranteed to pass and that they'll need to redo it (and get billed for more time) with a different solution if it doesn't.

Anyways, hope this helps.

 

[lexpatrie]

You kean a twsting agency don't you? A special inspector does not typically perform testing.....

I think a lot of folks are going to throw up the "what if the testing is not performed" (to me that feels fairly typical unless there's a lot of involvement from the EOR making a bunch of phone calls and sending letters to the building department. (Where I am)...

Further complication, several states delete special inspection provisions from their codes. Some replace the language, others delete without substitution.

If the test fails to achieve the desired load is the concrete damaged?

Personally, if the special inspection isn't done (hole drilling, cleanout, temperature, etc.), the pull testing isn't going to be successful....