Post-Cast Anchor in Thin Concrete (Need Product Recommendations)

[P1ENG]

This is less a engineering question and more a product question. I have someone wanting to anchor to an existing 3" thick, light-weight slab in seismic design category D (cracked concrete). I can't find any anchor that is tested in anything less than 3.25" (1/4" Hilti KB-TZ2). LRFD shear load per anchor is very small (70 lbs) and no uplift. It's such a small load, I'm not worried about any anchor that is decided upon, but showing it to work on paper is something else. So any products that I can use in light-weight cracked concrete that is only 3" thick?

If not, I was thinking about using an anchor rated for use in CMU thinking that would be conservative and hoping the AHJ wouldn't argue?

Juston Fluckey, SE, PE
Engineering Consultant

 

[Enable]

Have you tried looking at Hilti KH-EZ Screws? You can get the 1/4" to work in ~2" of concrete and they are rated for seismic applications.

 

[P1ENG]

Have you tried looking at Hilti KH-EZ Screws? You can get the 1/4" to work in ~2" of concrete and they are rated for seismic applications.

Looking at ESR-3027, the 1/4" anchor requires 3.25" thickness:

Juston Fluckey, SE, PE
Engineering Consultant

 

[Enable]

My apologies. I erroneously assumed given the thickness and light-weight concrete that this was concrete over a metal deck, which only requires a minimum thickness of 2-1/2" for the 1/4" KH-EZ. Nothing else comes to mind unfortunately.

 

[Deker]

Hilti HDI-P TZ might work: Link. If not, perhaps you can justify with a load test. Here's a thread dealing with a similar situation: thread507-361097.

 

[P1ENG]

Deker,
Thanks! That one looks promising. I'll pursue that one if the client comes back and confirms the 3" thickness. They told me 3" but they originally said 4". So I just want to make sure they don't really have a little more than 3" which would solve everything.

Juston Fluckey, SE, PE
Engineering Consultant