RESEARCH ON SEISMIC BEHAVIOR AND FAILURE MODE OF “STRONG BEAM AND WEAK COLUMN” PC JOINTS

To investigate the seismic behavior of the "strong beam and weak column" PC frame joints, the quasi-static test of two full-scale "strong beam and weak column" PC frame joints with different axial compression ratios and a cast-in-place comparison specimen were designed and completed. The hysteresis curves and failure modes of such joints were obtained. The test results showed that after the column end of the PC joints yielded, the horizontal shear cracks appeared on the composition plane of the upper part of joint core area, and then the tensile fracture of reinforcement bars of the column in sleeves occurred and the column lost its bearing capacity. The failure mode of the RC joint was shear failure of the core region after the column end yielded and the structure still had a certain bearing capacity and plastic deformability. The initial stiffness of each joint was approximately the same, and the seismic bearing capacity of the RC joint was significantly better than that of the PC joints. The ductility factor of the RC joint was 3.23, while the failure mode of PC joints was brittle failure. In conclusion, the "strong beam and weak column" PC joints showed poor seismic behavior, and its failure mode was column end shear brittle failure,which should be avoided in design and construction.