EXPERIMENTAL STUDY ON THE SEISMIC BEHAVIOR OF PRECAST CONCRETE BEAM-COLUMN JOINTS WITH CONNECTION DEFECTS

To analyze the influence of connection defects on the seismic behavior of precast concrete frame beam-column joints, three typical defects in the core area of precast beam-column joints were considered. Five precast concrete beam-column joints and one cast-in-situ concrete beam-column joint were tested. The failure pattern, hysteretic characteristics, skeleton curve, stiffness degradation and energy dissipation capacity were analyzed. The nonlinear finite element analysis program OpenSees was used to simulate the precast beam-column joints. The bond stress-slip relationships and the shear behavior of the joint area were considered in the joint model. The results indicate that the concrete casting defects in the core area had great influence on the strength and energy dissipation capacity, that the defect of the rough surface and of the grouting layer at the bottom of the column had little impact on the seismic behavior of the joint, and that the weakening of the bond of steel bars can be effectively simulated by considering the bond stress-slip relationships and the anchorage length in the finite element model. The model can be used for further structural seismic performance analyses.