ACI 318 Anchor Design for Concrete over Steel Deck

[n8structural]

Does anyone have a good reference for designing embedded anchors (or post installed anchors) in concrete over steel deck? One topic I have had to deal with lately is designing anchors (embed or post installed) into concrete over steel deck. For instance stair stringers that attach to the edge of a floor slab (concrete over steel deck). Edge distances will obviously vary depending on the direction of the deck. But does concrete break out still apply if it is supported by the steel deck? ACI does not address this type of condition (that I have found). I seem to be taking the worst case edge distances and break out areas, and while I am confident I am being conservative, I don't want to be discounting the effect of the steel deck, if allowed. Does anyone have any direction or resources they could share?
Thanks for your time.

 

[mike20793]

For post installed, I usually reference the Hilti or Simpson (or other anchor manufacturer) load tables. They will account for edge distance, spacing, etc. For something cast in place, I will usually try Simpson's or Hilti's anchor designer software. If I still have a condition not covered by either of those two, then I will go through the ACI calculations via spreadsheet (for iterations).

Edit: If you are looking at post installed concrete over metal deck, check out Simpson. They have load tables for installing above and below the deck.

 

[KootK]

But does concrete break out still apply if it is supported by the steel deck?

I believe that it does and would need to be addressed via one of the methods that Mike mentioned. My sense of things is that you would fail the concrete in breakout etc first, and then engage the deck for whatever it's worth. I don't see having both mechanisms in play concurrently.

For instance stair stringers that attach to the edge of a floor slab (concrete over steel deck).

Definitely a breakout situation if the stringers will be vertically hung from the deck. And probably a challenging situation at that.

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.

 

[steellion]

Hilti also has tables and guidelines for minimum edge distance, spacing, etc., for post-installed anchors into concrete on metal deck. Only certain types are suitable for this condition.