Acceptable/Unacceptable Standard Industry Practices For Setting Anchor Bolts 1

[ThermoCrust]

Good Afternoon!

I am not an engineer. I provide information to engineers, surveyors, project managers, and individual clients through drone services in the form of live-stream monitoring, photogrammetry, and LiDAR services.

I was on a job where I provided all of my aforementioned services to the client for their construction project. Based upon on-site observations, reviewed video footage and photos taken the next morning I felt this final product was worse than what I had observed in the past. I don't pretend to play engineer or know the ins and outs of setting anchor bolts but I was curious to find a resource that highlights the acceptable methods of setting anchor bolts for my own professional and personal development.

Here's the footage I captured for your viewing pleasure. The property owner has me scheduled to meet with them and their engineer and structural inspector to go over the footage on Tuesday, I would like to mark the various questionable methods used in the video to help expedite our review time together. Thank you!

https://youtu.be/qoHsWL7N4Zw

 

[bugbus]

Horrifying. This is a 'rip it up and start again' type deal.

 

[phamENG]

Wow. Those anchors are essentially worthless.

 

[MyCupboard]

This is poor workmanship. Agree with phamENG, the anchors are worthless. neat trick to get the placement correct by putting them through a piece of wood. This looks like they just forgot to set the anchor bolts, as opposed to this being their standard method of setting them. This is a no brainer and more work than setting them correctly. In the past, I've seen them set the anchor bolts not too long after the concrete is poured, as long as the slump is low enough that it can hold the anchor bolt up (i want to guess it was an hour but it's been a while so don't quote me on that). They just slowly plunge the anchor into the concrete and sort of agitate it once it's at roughly the final position. this is to make sure the concrete moves back into any voids that were created by plunging the anchor bolt.

 

[dik]

In these environs, the plywood template has a nut on each side stabilising the anchor rods and the template is raised by 1-1/2" (by dimensioned lumber) from the formwork. Not much can go wrong... but, always spec that anchor rods should be weldable.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[phamENG]

agree with dik on the plywood template - that's pretty standard. Once had to have a steel plate fabricated with a high precision center mark for a surveyor to place it - 4 legs of a 65'+ conveyor tower around a big hole in the ground. The tower manufacturer gave a tolerance of 1/16" for each bolt.

MyCupboard - you're describing wet setting of the bolts, a practice I specifically call out as not permitted. If the concrete is wet enough to 'reform' around the bolt or dowel, it's not strong enough to hold it up. If it's strong enough to hold it up, it's not workable enough to fill voids created by wet setting. There might be a magical point in between where it is, but I don't trust any contractor to pick that perfect moment to do it. After all, most can't get saw cut timing right.

 

[MyCupboard]

PhamENG - interesting! I’m in residential in the northeast and that’s the way I’ve seen it set millions of times (I know that doesn’t mean it’s right - but that’s where my assumption came from). Maybe that method is only okay for standard sill plate settings (not a moment frame or steel column, etc). I’ll look into our notes and the code to see where my assumption originated. Thanks for pointing that out.

So do you just have all anchor bolts post installed? And are you talking residential or commercial? All instances or just ones excluding the standard sill plate anchors?

I’m always learning! Thanks for helping

 

[dik]

Other than being 'out of whack' (by misplacing) the only problem I've ever encountered with tilted anchor rods are those that have been 'nudged' by equipment... I've never encountered a 'tilted' install.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[phamENG]

MyCupboard - I do mostly residential now, but I cut my teeth in commercial/industrial, so my expectations make most residential contractors cringe. I don't care, though - reduced need for reliability of a structure is accounted for in design, not by the builders doing bad work. The practices should be similar - the difference is in the embedment of that anchor for higher loads in higher reliability buildings.

Reinforcement shall be secured in the proper location in the forms with tie wire or other bar support system to prevent displacement during the concrete placement operation...

The IBC and ACI have similar restrictions. ACI 301, Specifications for Structural Concrete, state this:

Before placing concrete in forms, complete the following:...Position and secure in-place expansion joint materials, anchors, and other embedded items.

I'm not sure of anything in the IRC that specifically prohibits it for anchors, but there's enough other evidence out there that it's a bad practice that I have no problem disallowing it on projects I'm associated with. As EOR, it's my prerogative to enforce rules above and beyond the minimums in the code (I just can't require less).

Also, search on here for wet setting...there are a lot of threads that discuss it.

EDIT: oh yea, I hate post-installed in residential work. 99.9999% of foundation walls here are CMU, and options for post installed anchors that provide a meaningful uplift connection into CMU (as part of a complete load path) are essentially zero. There just isn't enough room to drill and epoxy while also missing either bond beam rebar or vertical rebar (either of which is required to develop the strength of the anchor because masonry design codes prohibit the use of unreinforced masonry to resist directly applied tension - only flexural tension is permitted to be resisted by mortar alone). And it never gets inspected. I once walked a jobsite and, for the fun of it, reached down and grabbed the anchor in a hold down...and picked it up out of the hole. The contractor almost recovered his shocked look before I turned to face him - he was 'going to do the epoxy later'. yeah, right...