Epoxy Anchorage for Continued Tension Loads

[CBSE]

What is the general consensus for using epoxy to anchor threaded rod that holds folding doors into concrete above? For some reason I thought I remembered something that prevented this in the code, but I can't seem to dig it up in my laundry list of "remember to's". Load is about 600lb per bolt.

 

[KootK]

In the aftermath of the big dig, we worry about expoxy anchors in permanent tension having creep issues. I'd check with the manufacturer about that if you're going epoxy. I'm not sure if there's a code clause dealing with this.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[XR250]

I am just as concerned about the anchors being installed properly as their creep resistance in overhead conditions.

 

[jreit]

After the Boston tunnel incident, this issue was given a lot of attention by some (if not all) DOTs. If you're in NY, NYSDOT does prohibit this as far as I know. You might find the restrictions in the Standard Specifications.

 

[SteelPE]

I also seem to remember about epoxy anchors being installed overhead taking sustained tension loads/creep in combination with installation reliability (they had problems with the epoxy leaking out of the holes during installation because Gravity was working against you). Then there were fire concerns with the use of the anchors as well, since the epoxy softens a relatively low temperatures.

As others have said, check with the mfr.

 

[SAIL3]

I would not advise it, period....

 

[darthsoilsguy2]

FYI. Undercut anchors were promoted after the Big Dig. not sure to what extent, but here is a link to a photo of then Governor Mitt Romney holding one

http://smg.photobucket.com/user/wildeyedliberal/media/mittthetard.jpg.html

. HILTI will ship you 2 books (designer & an installer) that covers all their anchor systems and all the how-to's.

(also FYI, i just googled and landed on that image. i'm guessing the person who posted the picture didn't vote for Mitt...)

 

[CBSE]

Thanks for the info. I did some additional reading last night and it appears that it is acceptable to use Epoxy in over-head situations provided the product is explicitly tested for long-term creep at elevated temperatures. I found both Hilti and Simpson to have a product for this. Now, I just need to check my local jurisdiction code.

@ darthsoilguy2...not sure I like politicians getting into engineering

 

[SAIL3]

as XR250 stated, can you guarantee that the ABs were installed properly?....

 

[Gumpmaster]

Things have changed quite a bit since the Big Dig failure:

1) There has been much more product testing/product refinement to help minimize this problem.
2) There has been much more refinement to adhesive installation requirements and procedures.

I don't see a particular problem with this, although there are more reliable choices. If you do decide to use adhesive anchors, consider requiring that the installers are certified per the ACI adhesive anchor installer certification program. During this program the installers have to prove they can install effectively in overhead applications. Also consider requiring something like Simpson's Adhesive Piston Plug Delivery System which ensures the hole is properly filled with adhesive.

 

[thaidavid40]

Not to minimize the application here, but at least you are only holding up doors - and not walkways or floors. I think that before you use epoxy anchors in this application, even if the manufacturer has an approved tension-rated adhesive, you should maybe consider going back to using undercut anchors instead. From my experience, most folding doors experience a good deal of dynamic, and lateral, loading during their lifetimes. These loads, in concert with the permanent tension loads, would give me pause when considering epoxy anchors. I would personally feel safer with the undercut anchors in this case. Just my two cents' worth.

Thaidavid