Wet Setting Anchor Rods

[WiSEiwish]

Wondering what the thoughts on here regarding wet setting anchor rods. In my opinion it is implicitly prohibited by ACI as the two types are cast-in which is defined as having concrete cast around the anchor rod or post-installed which is defined as anchoring into hardened concrete. Since essentially all of the anchorages into concrete that are specified are either cast-in or post-installed it would seem that there is no way for wet setting to be permitted. This is in addition to it just seeming like a really bad idea.

 

[Rabbit12]

You're correct. It's a bad idea.

 

[azcats]

I'd consider allowing it in a situation where the bolts are small and not highly loaded *and* the concrete had been placed within the last few moments **and** they re-consolidated after setting the bolts.

Big bolts, deep embed, high loads - no way.

I wet set the 3/4" bent anchor bolts for my kids' basketball standard and so far it hasn't fallen over on my wife's car.

 

[msquared48]

Never... regardless of the load.

Mike McCann, PE, SE (WA, HI)

 

[canwesteng]

If the loads are small enough you'd consider wet setting the anchors why not just use tap cons or another concrete screw and keep your hands clean? Can't imagine a wet set J anchor is even that strong.

 

[birneys]

I've had contractors throw all kinds of justification at me to allow wet-setting, including a letter from another "engineer" that quote "wet-setting is industry standard". I believe there is an explicit statement that all items to be embedded in concrete have to be secured in place prior to concrete placement. Can't remember the section off the top of my head, but I don't allow it under any circumstances.

 

[WiSEiwish]

Pretty much the reaction I expected...and I agree. There is no capacity guarantee unless each one is load tested.
I also see it implicitly forbidden by IBC.

 

[GC_Hopi]

Agreed but I would add that my main concern is quality control. Wet setting denotes a lower quality of workmanship and higher risk of improper installation. I have tested poorly installed wet set bolts that failed at ~300 pounds.

 

[Lomarandil]

Out of curiosity, how do these concerns translate to dowels? (Say drilled shaft to column)

----
just call me Lo.

 

[phamENG]

If you wet set an anchor (or dowel), you're doing it because you didn't want to take the time to measure, tie, and/or build a template to place them accurately and securely. If the concrete is too wet, it'll just sink or lean and you'll be left with a mess, so you wait until the concrete has set up just enough that you can push it in but it stays in place. This doesn't sound like concrete capable of completely consolidating around an anchor or dowel to me. If you vibrate it to make it consolidate - what happens to your embedded material? It sinks, or leans, and you have a mess. So I can't think of a scenario where wet setting gives you an equal result to properly tying prior to the pour - regardless of load or size.

 

[JoelTXCive]

Somebody should tell the residential homebuilders this is a no-no.

Prior to becoming an engineer, I worked as a residential homebuilder in Texas. I worked as a superintendent for a large homebuilder and also worked as a custom homebuilder.

A large majority of the homes in Texas are slabs on grade.

On 100% of the homes, the perimeter sill anchors bolts were wet set. This was (and remains) and industry standard procedure in the Houston area. When I started working, these were 1/2" or 5/8" L-bolts, but then the industry switched over to Simpson type Mudsill anchors.

While pouring the slab, there will be a group of workers placing the concrete. Following shortly behind was a guy with mudsill anchors. He would place them in the wet concrete on the perimeter of the slab.

Now I know why we lose so many homes to tornados...

 

[BridgeSmith]

Obviously, as several posters have mentioned, you can't count of getting full capacity, especially in tension. A wet-set J-bolt would have some marginal amount of tension capacity, but a straight rod would have very little. Shear capacity would likely be fairly decent with either one, albeit with somewhat greater displacement expected. For residential, where uplift is not a concern, it would probably not be an issue. That said, I wouldn't sign off or stamp my approval on it.

OTOH, based on our experience with the poor quality of the installation of epoxy anchorage systems, I'd prefer a wet set J-bolt for tension applications, if those were my options. If we need any significant tension capacity, we make sure they are forced to cast in the anchorage, typically by specifying a U-bolt, so they can't 'forget' to cast in the anchor bolts.

Rod Smith, P.E., The artist formerly known as HotRod10