Split and extend tie rebar at corner pile cap

[LewisLiew]

A pile cap with L shape will be constructed. Tie bar in Internal corner will always split and extent into pile cap with lapping length. I understand that the tie bar is useless if I am not doing so. Why and what this rebar/ fenomena called?

 

[KootK]

The tie bars (stirrups) are generally installed to resist shear forces. When diagonal shear cracks form in the concrete, the stirrups crossing the cracks keep them from opening up. The stirrups can't do this job unless they are effectively one piece from the top of the member to the bottom. The laps essentially stitch two piece stirrups together into a system equivalent to a one piece stirrup. As I'm sure you know, the stirrups are fabricated in two lapped pieces in order to improve constructability in some situations.

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