Shear Friction vs Shear Studs

[CoreyR]

I have a question about the connection requirements for shear friction (concrete to concrete) versus shear studs (steel to concrete). Why is it that with shear studs they typically only need to be embeded into the concrete a couple of inches (2" +/-) while the requirements for shear friction connections (per AASHTO) require that hooked dowel bars be embeded a minimum of 6". Aren't they both doing the same job?

Thanks
Corey R.

 

[DaveAtkins]

I'm not a bridge engineer (so am not familiar with AASHTO), but I assume the 6" is required to develop the hooked bar. A headed stud is developed by the head.

DaveAtkins

 

[J1D]

It seems to me that the anchors/rebars across a shear-friction interface is mainly used to guaranty the clamping force, and to contribute a shear component (if rebars in angle) against the apllied shear force, while the shear studs are designed with their shear capacity directly.