Post Installed Anchors to CMU

[bookowski]

I posted this in the fastening group but didn't get any useful tips, maybe someone here has some experience with this:

I need to attach plates to an existing cmu wall, my loads are in the 400#-600# range per anchor in tension and about 150# shear. These plates will support cantilever tubes so I want to have a good factor of safety in there. I have some questions about how people typically handle the following:

- Most likely the anchors will hit a mix of solid and hollow cells. If I go with Hilti they recommend a different anchor for each condition - do you spec both and make the contractor switch back and forth? Powers recommends the same epoxy for both hollow and solid cells, this seems less likely to contractor mix up.

- Most anchors are shown as not applicable at or near the mortar joint, I can't really control the location of these anchors. Do you typically deal with this by adding additional anchors assuming that some will be ineffective?

thanks

 

[hokie66]

Yes, that's what I mean. And getting them in the right spot does take a bit of effort. When I get this excuse, I just point out to the builder that post-installed anchors were not always an option, and if they could do it properly years ago, why not now?

 

[anchorengineer]

Bookowski
It's from experience that I know you can use HY-20 in solid masonry. Typically the masonry is the weakest element anyway. If you don't feel comfortable with HY 20 you can use HY-150 max. Hilti actually has test data in their tech guide that gives capacities in CMU. HY 150 MAX was designed so it can be installed into holes that are up to 1/4" larger than the threaded anchor rod. So if they hit a solid cmu you could essentially eliminate the rod (assuming the installer is competent). You could always just use the screen tube anyway in case the installer can't tell if it's solid or not. The holding mechanism will be bond instead of keying in solid holes. Cleaning the holes is obviously important here.

http://www.anchorengineer.com

 

[anchorengineer]

bookowski - No emails are allowed on this forum. You can check out my webpage for what I can do.
Thanks!

www.anchorengineer.com