摘要:
为研究"强梁弱柱"型预制混凝土(PC)框架节点的抗震性能,设计并完成了不同轴压比的2个足尺"强梁弱柱"型PC框架节点和1个现浇混凝土(RC)节点对比试件的拟静力试验,获得了此类节点的滞回曲线及破坏模式。试验结果表明:PC节点柱端屈服后,节点核心区上部叠合面迅速出现水平剪切裂缝,随后套筒内柱筋被拉断,柱失去承载能力;而RC节点为柱端屈服后的节点核心区剪切破坏,柱端屈服后,结构仍具有一定的承载力和塑性变形能力。3个节点的初始刚度大致相同,RC节点抗震承载能力明显优于PC节点。RC节点的延性系数为3.23,而PC节点为脆性破坏。该类型的"强梁弱柱"型PC节点抗震性能差,其破坏模式为柱端剪切脆性破坏,设计施工中应避免出现这类节点。
Abstract:
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.