Effects of Joint Configurations on Shear Behavior of Prefabricated Segmental Cap Beams

The joint configurations of prefabricated segmental cap beams exhibit considerable diversity in engineering applications. In recent years, combined shear key corbel connections have been increasingly adopted due to their advantages in prefabrication efficiency, rapid assembly, and favorable mechanical performance. Nevertheless, research on their ultimate shear capacity remains limited. To systematically assess the effects of joint configuration on shear performance, two types of cap beam models were developed reflecting engineering loading characteristics dominated by positive shear with secondary negative shear effects: a shear key model (SK1) and two keyed corbel models (SK2 and SK3), subjected to positive and negative loading, respectively. A full nonlinear static analysis with progressive loading to failure was conducted to obtain cracking load, ultimate capacity, stress distribution, deflection, and damage evolution. The results reveal that (1) all beams exhibited damage localization near adhesive joints, with shear–compression as the governing failure mode; (2) SK1 and SK2 achieved comparable shear capacities, whereas SK3 reached less than 30% of their ultimate strength; (3) SK2 attained the highest ultimate capacity, 1.07 times that of SK1; and (4) SK2 reached a maximum deflection of 3.24 mm, exceeding the other two by more than 29%. Overall, the keyed corbel configuration (SK2) demonstrated the most favorable comprehensive shear performance.