Shear Friction - Cast in Place Concrete & Precast Concrete 2

[PEFLWI]

I have a shear friction question. I am involved in a project where the structural engineer specified hollow precast concrete piles. See the attached sketch. This is already built. The connection of the pile to the pile cap is through rebar and poured concrete in the top of the hollow pile. See the sketch. It appears the engineer is counting on friction between the cast in place concrete and the inside surface of the pile. I understand ACI 318 to allow shear friction only if there is rebar across the joint. Since there is no rebar between the CIP concrete and the precast pile, ACI would not allow the use of the shear friction concept. Do you agree?

 

[hokie66]

How were these piles cast? Like precast power poles, which are spun, normally pretensioned longitudinally with spirals around the longitudinal reinforcement? I’d so, the annular space will have residual laitance.

 

[ALK2415]

@ OP
'horizontal reinforcing in the piles' Always added to piles !!!

your structure layout

 

[user277418]

But for c*fctd, the language is "if the joint can be significantly cracked." I interpret that that if you can prove that service limit state checks are satisfied, then cracking will remain within allowable limits - i.e. not "significantly"

Would be nice to have explicitly stated value. Otherwise how much "sagnificantly" is? If the interfaces are detached (even for 0.1 mm) then any cohesion/bond is lost. Only aggregate interlocking remains. Available degree of the interlocking in the current case is questionable. If the uplift force is significant (i.e. a pile cap of a transmission tower leg) I would prefer to be on a safe side.