Bending behavior and cracking resistance of UHPC wet joints in prefabricated multi-girder bridges

UHPC is well acknowledged to possess excellent bonding performance, making it favorable to be used in prefabricated bridges. This paper focused on the bending behavior and cracking resistance of UHPC wet joints in prefabricated multi-girder bridges. Four-point bending tests on ten bridge panel specimens with the UHPC wet joint were carried out. On this basis, a refined finite element model (FEM) was developed based on ABAQUS to simulate bending behavior of the UHPC wet joint. The cohesive element was utilized to simulate the UHPC-NC interface. The FEM was validated through a comparison with experimental data, including load-deflection curves and failure modes. The results demonstrated good agreement, confirming the model’s reliability in predicting the bending behavior and cracking resistance of the UHPC wet joints. Subsequently, a parametric study was carried out on 36 UHPC wet joint specimens. The effect of the interface shape, overlapping form and length of the longitudinal reinforcement, and reinforcement ratio in the wet joint on bending behavior of the UHPC wet joint was evaluated. The parametric study indicated that the rhombic and groove shape wet joints exhibited better cracking behavior than the rectangular wet joint. The overlapping form and length of the longitudinal reinforcement had negligible influence on bending behavior of the UHPC wet joint. Additionally, increasing the reinforcement ratio from 1.13% to 1.35% significantly enhanced the flexural capacity of the joint. Finally, an analytical model was proposed and verified to be reliable in predicting cracking resistance of the UHPC wet joint under bending moment. The present study provides important design guidelines of the UHPC wet joint, which are beneficial for its engineering application.