Mounting unistrut to 8" hollow core precast slab?
Mounting unistrut to 8" hollow core precast slab?
(OP)
We need to mount unistrut to the underside of 8" hollow core precast slabs. The slabs are existing and the cores are unfilled. There is a topping slab that fills the gaps between the slabs.
Can post-installed anchors be installed into the infill concrete between the slabs? I'm worried about hitting reinforcement or the 1.5" thick area below the hollow areas. Is there any published guidance for installing anchors between precast slabs?
Can post-installed anchors be installed into the infill concrete between the slabs? I'm worried about hitting reinforcement or the 1.5" thick area below the hollow areas. Is there any published guidance for installing anchors between precast slabs?






RE: Mounting unistrut to 8" hollow core precast slab?
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Mounting unistrut to 8" hollow core precast slab?
https://www.us.hilti.com/medias/sys_master/documen...
RE: Mounting unistrut to 8" hollow core precast slab?
At the side joints you'd be dealing with cold joints and a narrow grout thickness. You'd want to go deep and, if it's a load that matters, consider some in situ testing.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Mounting unistrut to 8" hollow core precast slab?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Mounting unistrut to 8" hollow core precast slab?
RE: Mounting unistrut to 8" hollow core precast slab?
TehMightyEngineer: We have 2 200lbf loads at the 1/3 points of a 4' long section of P1000. Although once this in place we expect other to attach to the unistrut for convenience.
StructSU10: I was unaware of HDI-P sleeves, what kind of anchors can fit in the sleeves?
jayrod12: It looks like the HY70 will also work for this application
RE: Mounting unistrut to 8" hollow core precast slab?
There are code approved, internally threaded inserts that can be installed into a 2" deep hole. X-ray the slab for tendons in any case (don't you dare nick a tendon).
RE: Mounting unistrut to 8" hollow core precast slab?
RE: Mounting unistrut to 8" hollow core precast slab?
RE: Mounting unistrut to 8" hollow core precast slab?
I think you have a transpose error. The I of a P1000 is 0.185 NOT 0.815.
And when you say 2 200lbf, you mean to 2 @ 200 lbf, not 2200 lbf, right?
RE: Mounting unistrut to 8" hollow core precast slab?
If the concrete (or grout?) between the hollow core slab is allowed to reach at least 7 days of cure time, for what reasons is adding anchors there an issue?