Post-cast anchor in prestressed concrete 1

[P1ENG]

My Eng-tips search did not result in an answer.

I am anchoring a shearwall to a concrete slab. The concrete slab is prestressed*. Are there any special requirements or limitations on using mechanical or adhesive post-cast anchors in prestressed concrete? I checked Hilti's RE500 ESR for example and the report did not specifically mention prestressed, post-tensioning, etc.


* Prestressed concrete is not in my wheel house. I assume any method of inducing stress (post-tension, etc.) is called prestressed. If not, I can find out what method is used if that matters.

TIA,
Juston

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[Ingenuity]

The "special requirements" for installing post-installed anchors (or generally any type of drilling, cutting and coring too) in prestressed concrete is not to hit the prestressing tendons. For precast prestressed products the tendons are pretensioned strands, and for post-tensioned concrete they are either UNbonded or bonded 7-wire strands, most commonly 1/2" diameter.

Always best to scan the slab or beam before drilling and installing post-installed anchors.

 

[P1ENG]

Thanks for the quick reply. That was all I could come up with. I have already called out that installer is to avoid the prestressing steel, but the contractor/architect reviewed and said they wanted a different method of attachment as it "wasn't a good idea to drill a hole in the PS slab". The comment threw me, so I decided to seek advice here. I don't know how they think they are going to anchor it without drilling holes if they didn't embed anything when casting.

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[KootK]

For wood sill plate:

1) you can use something like a Rawl drive pin to improve the odds.

2) I've heard folk propose glue in the past. Obviously, some concerns with that.

Neither option gets you out of dealing with tie down anchorage.

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.