Corrosion Protection for Post-installed Anchorage of Temporary Structures to Concrete 1

[NWEng1]

What level of corrosion protection is required for anchorage of temporary structures (2-3 year service life) to concrete?

I'm designing anchorage of an exterior personnel hoist for a high rise to a concrete pad footing using post-installed anchors. The service lifetime will likely be on the order of 2-3 years. In terms of strength, the Hilti HSL-3 looks like an ideal anchor as it is rated for support of heavy-duty dynamic loading, but in terms of corrosion protection is recommended for indoor dry applications only. I could require regular inspection of the anchors on the drawings, but the actual anchor sleeve itself is most likely to corrode and will not be visible. Not to mention that a requirement on the drawings does not guarantee that it will be implemented by the workers.

Alternatively, I could spec a stainless steel Simpson Titen HD, but I'm not sure how great they are for dynamic loading.

Opinions are appreciated!!

 

[hokie66]

I would be comfortable with that anchor for 3 years. The zinc plating does some good, and it is a quality anchor. I assume the personnel hoist is tied to the building as you go up.

 

[TehMightyEngineer]

I'd also be comfortable with those for a 3 year service life. Most of our cast-in threaded couplings for our precast stairs are only zinc coated and and they're viable for many years beyond the install date.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/

 

[P1ENG]

NW: It is not recommended for indoor, dry locations; it is required (limited to) by the ICC report. You may want to call Hilti, ask for an engineer, and ask for the reason for that exclusion and see if they have some insight. You and I know that it will be fine, but one failure, one injury, you're very liable because the "improper" bolt was used. Even if the failure mode had nothing to do with the wet condition.

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[NWEng1]

Thanks all, for your insight.

Hokie - yes, the hoist mast ties will be anchored to the building at 30 ft max along entire mast height. The demands on the pad anchorage are primarily only during install, where the mast will be temporarily free-standing.