Epoxy Holdown

[SJBombero]

Does anyone have a clue how this detail might be justified? I found it on a structural drawing approved by the AHJ in California. The stemwalls are typically 8" thick. I tried to justify these several years ago but got shut down by the AHJ. Now I just specify through bolts. Assuming that someone found a way to justify some of these values, the glaring errors I see are HDU5-11 have embedment values beyond the limits of the ESR reports, minimum edge distances have not been met. The only thing I can think of is perhaps they are counting on the single bar that typically runs through the top of the stemwall to restrain a breakout wedge and ignore all the other violations.

 

[Greenalleycat]

Well, in my country at least, you could put a capacity to that. I assume they did and decided it was sufficient so it was OK.

I don't like that detail though as there seems to be no steel connection between the upright and the footing? So it relies purely on concrete in tension

 

[JedClampett]

There's a relatively new approach in the epoxy business, where if you fully develop (like 20 inches for a #4) a bar in epoxy, you can treat it like a reinforcing bar. In other words, edge distances and spacing for epoxy anchors can be ignored. Now this is a steel rod, not a reinforcing bar, but the logic seems the same. This is Hilti's approach.
Greenalleycat, as far as the lack of reinforcing in the stem and footing, I think this is a retrofit in a building where there's no drawings, so the designer left out what he wasn't certain of, like the size and spacing of the bars.

 

[Aesur]

@JedClampett - I have heard of the approach you mention and while I understand that they are "developing the bar" I would argue that you still need to check breakout, shear, etc. per ACI as this is still an anchor. I have seen engineers for years say a developed bar doesn't need to meet anchor requirements (formerly chapter D of ACI), however by doing this they are saying that if I embedded a bar in say a 5 inch square column then I get full strength of the bar, that isn't even remotely true. To your point, it may have been that the EOR on the detail above checked all this for their project and it worked, it's hard to say. He may have also lapped to an existing bar (even though the detail doesn't say as such) to drag into the foundation.

 

[SJBombero]

If the EOR checked it, he must know about some trick that I don't. A Ø1" anchor rod, 2" from the edge of an 8" stemwall with 11 kip x overstrength is not going to calc out. Whether it works IRL or not is another topic.

 

[Enable]

Aesur: I don't believe that JedClampett is saying breakout and other checks don't apply. I believe he is saying that any peculiarities applicable only to post-installed anchors do not need to be considered if the anchor is fully developed in epoxy. Any requirement for reinforcing steel would still need to be checked (as the epoxied anchor is now considered a reinforcing bar), and as you note, concrete breakdown is one of those.

 

[Aesur]

@Enable, I believe you are correct, I didn't mean to imply or direct my message toward him, was more of a general response in regards to other checks still apply, sorry for the confusion.