Study on the performance of cast-in-situ concrete wet joints in PCSBs under cyclic loading

The closure section of precast concrete segmental bridges (PCSBs) usually adopts the wet joint, the regular longitudinal reinforcement is discontinuous, which makes the section the vulnerable part. To study the performance of the wet joint in the closure section under cyclic loading, six specimens considering loading mode, interface treatment method, setting of regular reinforcement and prestressing are tested. Results show that the damage of the wet joint accumulates and the plasticity develops under cyclic loading, the specimens undergo residual deformation, strength attenuation and stiffness degradation. Increase in prestressing level can delay the cracking, the cracking load of specimens with a prestressing level of 8MPa and 10MPa is 21.9% and 32.8% respectively higher than that of the specimen with a stress level of 6MPa, and the results also confirm that excessive prestressing level cannot significantly improve the shear strength of the specimens. When the controlled displacement is small, the residual deformation of the specimen is small and the strength attenuates slowly; with the increase in controlled displacement, the residual deformation of the specimen increases and speeds up, the strength decreases continuously, and the development of the crack tends to be stable, leading to the leveling off of degradation of the stiffness.