Research on the Influence of Shear Reinforcing Bars on the Seismic Performance of Prefabricated Joints

Based on the existing prefabricated concrete frame structure, the paper proposed a new type of prefabricated asymmetric hybrid connection joint (PPEFF joint). The longitudinal reinforcement of the beam of this joint was arranged asymmetrically, and only energy-dissipating steel bars were installed on the upper part of the beam. While the joint meets high construction efficiency, shear steel bars were installed on the contact surface of the beam and column, which improved the bearing capacity of the contact surface of the beam and column, so as to ensure the safety of the structure after the accidental failure of the joint prestress. In order to study the influence of the reinforcement ratio of shear steel bars on the seismic performance of PPEFF joints, the paper combined low-cycle reciprocating load test and ABAQUS finite element software simulation analysis, focusing on bearing capacity of joint, energy-dissipating capacity, stiffness degradation and self-restting capacity, etc. The influence of the reinforcement ratio of shear steel bars on the seismic performance of joints was analyzed from these four aspects. Through the research in this paper, it was found that the PPEFF joint had better seismic performance, and the increase in the reinforcement ratio of the shear steel bars would increase the joint bearing capacity, stiffness, and energy dissipation capacity. However, the setting of shear reinforcement improved the section stiffness of the joint and inhibited the self-resetting capacity of the joint to a certain extent, which violated the original intention of the self-resetting capacity of the pre-compressed assembled joint. Therefore, it was recommended that the reinforcement ratio of shear steel bars in PPEFF joints should be set to 0.3% to 0.5%. At the same time, the calculation formula for the bearing capacity of the beam-column contact surface of the PPEFF joint was proposed, and the applicability of the calculation formula for the bearing capacity of the beam-column contact surface was verified through the test data and the simulation data.