Holding down concrete to a metal roof deck for uplift?

[abusementpark]

I am designing a hurricane shelter and the owner wants concrete on the roof. We are doing 4" normalweight concrete on a vulcraft 1.0C non-composite 22 gage form deck over open web steel joists at 2'-0" on center. I need to find some way to positively secure the concrete to the metal deck for the high uplift.

Any suggestions?

 

[KootK]

Thanks for reporting back to update us abusement.

I also spoke with a local steel fabricator who indicated I should assume the studs will be hand welded (too few studs to get the stud gun guy out there) and will cost about $5 per stud.

Is that hand welding in the field? If so, that doesn't seem too bad price-wise.

 

[BridgeSmith]

"...that doesn't seem too bad price-wise."

I'd agree. We paid closer to $10 per stud to have about 3000 studs automatically end-welded in the field on an existing bridge superstructure. That seemed like a good price when I saw the setup required for it. The welder was the size of a large chest freezer and the generator the size of a small car - like one used to power carnival rides. It was all mounted on a tractor-trailer flatbed. Granted, these were 7/8" studs that took around 1100 amps to the stud gun to weld properly. It's essentially stick welding with a 7/8" diameter welding rod.

 

[abusementpark]

KootK, that $5 per stud is supposedly for fillet welding in the field. The same guy told me it was normally $2 to $3 per stud for a large job with a lot of studs using automatic end welding. So maybe he just doubled the price without much other consideration?

I agree, I thought it would be worse.

 

[Deadblow]

I'm sorry I don't have valuable input, but a question.

The goal is resistance to wind uplift, presumably from air pressure on the underside of the deck, correct? That being the case, the uplift is on the steel decking, not the concrete.

I thought wind uplift on a roof is caused by the wind blowing across the surface and "sucking" it up. Is this not the case in this situation?

EIT

 

[BridgeSmith]

Deadblow, while it's possible to get some amount of uplift from the vacuum effect you describe, the primary source for uplift on a roof system is from a pressure differential between the building envelope and outside, such as when a door is opened on the windward side of the building.