Shear Stud Design
Shear Stud Design
(OP)
Question regarding the design process for shear stud connectors...
I'm designing an H-Pile to concrete cap connection using shear studs due to high tensile loads in the pile. My immediate thought process is to design the connection using a shear friction approach, with appropriate checks against concrete breakout, etc. In other words, I would design the shear studs in tension.
Initial calculations suggest a 3/4" stud (smallest available from Nelson) needs to be embedded at least 12" to be fully developed. This seems excessive because I've seen much shorter studs in composite bridge decks before.
I feel like I'm missing something so I wanted to see if anyone could point me in the right direction. Is shear friction not the correct approach for some reason?
Thanks!
I'm designing an H-Pile to concrete cap connection using shear studs due to high tensile loads in the pile. My immediate thought process is to design the connection using a shear friction approach, with appropriate checks against concrete breakout, etc. In other words, I would design the shear studs in tension.
Initial calculations suggest a 3/4" stud (smallest available from Nelson) needs to be embedded at least 12" to be fully developed. This seems excessive because I've seen much shorter studs in composite bridge decks before.
I feel like I'm missing something so I wanted to see if anyone could point me in the right direction. Is shear friction not the correct approach for some reason?
Thanks!






RE: Shear Stud Design
RE: Shear Stud Design
In my opinion, this kicks you into I8.3.
Again, in my opinion, this kicks you our of I8 altogether. I feel that neither the pile nor the cap is a true composite member. I think that the connection really has much more in common with an embed plate.
So what method should be used? I agree with cancmm's supposition that shear friction is the way to go.
What's governing the requirement for 12" studs? I'm going to hazard a guess here that it's ACI 318 APP.D breakout failure modes. If that's the case, then I'd like to suggest ignoring some of those failure modes. Tension breakout won't apply because when the concrete failure cone tries to break out, it will be restrained by the steel section that it's shearing against. I'd also argue that pryout would be moot in a confined concrete scenario. Shear breakout would apply but most of your studs will likely be far enough from edges that this won't matter much. The only concrete checks that matter, in my opinion, are bearing at the head of the studs and group action factors. And those should be easy to satisfy with proper spacing and head/shank proportioning.
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.
RE: Shear Stud Design
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.
RE: Shear Stud Design
RE: Shear Stud Design
If I remember correctly the capacity basically equates to a similar capacity you might calculate for a composite beam with some modifications. There is some enhancement due to the confinement of the concrete from the flanges when studs are on the Web of the H pile if I remember correctly.
RE: Shear Stud Design
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.
RE: Shear Stud Design
12" does not sound excessive at all if you are using it for direct tension. Composite bridge deck is using shear stud to resist shear, not direct tension so it make sense that they are usually very short (usually 4"~10"?). Maybe I am understanding the problem incorrectly, but for direct tension perhaps a different solution (i.e. not shear stud) may be merited? I have seen details before where there is a hole in the H-pile web/flange, and you use a 180 hook rebar to hook to H-pile, and the rebar would pretty much be the full depth of the pile cap.