Stud shear connector in 10 in. Concrete Deck

[shaukat1]

Composite deck slab 10" thick spans 8',8 ',8'(2 exterior span,1 interior span). Beam is W18x50(50 KSI) and spans 30'
(1 span only).Loading is AASHTO HL93. Recommended stud shear connectors (using 4 ksi concrete) number 56 studs
@6.4 in. on centers. Following art.4.6.2 Approximate method
(AASHTO), effective width for axle load(16000 lbf) is about
6'.Considering both axle load and Lane load, factored shear
stress is about 49 psi( effective d is 7"). Factored shear Resistance is about 126.5 psi. So factored shear stress is
less than half of shear resistance. In my thinking, the deck
does not need any stud shear connectors.

Is there any need for providing nominal stud connectors
along the span of the deck ? Away from the W beam, the studs
could only be welded to form metal. Even if the studs are
welded, would they work without distressing the metal deck ?

 

[scottiesei]

I'm not a bridge guy, but look at section 10.38.5 in the 17th ed. I am not sure how you would get a composite section without a connection from the deck to the beam.

 

[scottiesei]

Also, the AISC ASD 9th, section I5, not sure what the AASHTO equiv. is though, sorry!

 

[Dinosaur]

Stud shear connectors or other positive means for attaching the deck and girders are required to consider the beam and slab as acting composite in design. For short spans, you often have an extremely small spacing to satisfy development requirements.

Your span arrangement does not sound like a bridge, 8'-8'-8' with a single span at 30'. Are you saying the transverse section has three beams spaced at eight feet o.c.? And that the bridge is a single span of 30'?

 

[UcfSE]

Not providing any shear connectors sounds like you're relying on the bond between the beam flange and the concrete deck to provide for composite action, or between the deck connection to the beam. While it may work on paper, that doesn't sound like a good idea to me. Too many things can go wrong that would adversely affect the bond strength or the deck welds. In lieu of a better idea, I would ignore the contribution of the bond stress and provide studs to do all the work.

Studs would either be attached to the beam directly or attached to the beam through the metal deck, but not just to the metal deck. That wouldn't help much.

 

[miecz]

There is no reason to provide stud connectors along the span of the deck. One would never weld studs to the form metal since, as you say, they would distress the metal deck.

Section 9.8.5.3 (LRFD 3rd Ed) addresses composite action of corrugated metal decks. I've never seen composite metal deck construction on a bridge.