Crushing of Composite Metal Deck - 2

[RFreund]

There was thread regarding this some time ago here:

http://www.eng-tips.com/viewthread.cfm?qid=17976

LINK

This doesn't quite satisfy me (sorry Ron). It seems that if there was post that fell between deck flutes there would be an issue. Is there a calculation or some sort of testing that was done that could address this?

EIT

http://www.HowToEngineer.com

 

[jayrod12]

I don't know of any specific literature or calculation, but I would think it would depend significantly on thickness of concrete above the flute, and load on the post.

I do believe the steel deck guys publish web crippling strength of the deck, might be a place to start.

 

[KootK]

- I don't see web crippling entering into the equation. Either the concrete works on its own or the thing's shot. Any concentrated load that would compromise the concrete is going to make short work of the deck.

- A conservative approach would be to check the deck for punching shear under the load. If that passes, then you know that your load could make it over to the ribs successfully. After that, it's just bearing stress. I imagine that this would be quite conservative however.

- In reality, I suspect that an arching mechanism develops to move the load laterally to the ribs. That would have a ton of capacity. The trouble is that arch would require a tie. And a tie made out of sheet steel and puddle welds/pins is a pretty tough thing to quantify.





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.

 

[KootK]

You didn't ask for an alternate solution but I can't resist the temptation. Stick a little HSS filler under there. Like squash blocks in wood.

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.

 

[WARose]

I seem to recall a equation by SDI (or somebody) that specifically addresses this for deck (alone). I've got it around here somewhere. However, as KootK pointed out: the concrete strength will control.

 

[XR250]

non-shrink grout?

 

[RFreund]

Thanks for the responses. I do have some tables for metal deck only and they are higher than I thought, but I'm looking for the composite strength.

With how popular Cold Formed Steel framing with podium has become (atleast near me) I'm surprised there isn't some information out there on this.
There are a couple of work arounds:
1. Blocking as Kootk mentioned
2. Stop the deck at the beam flange and pour solid concrete above the beam.
3. At a post you could weld a short HSS on to the beam with a top plate that is flush with the floor.

Still I'd like to have something to understand the strength of the composite deck...

EIT

http://www.HowToEngineer.com

 

[KootK]

4) if this is a CFM post within a wall system, you could supply a 1/2" x 6" x 9" steel base plate beneath the the the post to get the load out to some ribs.

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.