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为了进一步研究新型PEC柱-钢梁T形件焊接加强型中节点的抗震性能,考虑柱轴压力、PEC柱布置方式和钢板组合截面类型等设计参数,设计制作了4个中节点1∶1.6缩尺模型试件,并对其进行水平低周往复荷载试验,观测记录了各试件试验中钢材屈服或屈曲与混凝土裂缝与压溃现象,得到试件的荷载-位移滞回曲线和破坏模式。根据试验结果分析了试件的承载能力、节点连接转动刚度退化、耗能能力和节点传力机理等抗震性能。结果表明:PEC柱组合截面翼缘采取卷边措施增强了核心区混凝土的约束作用;PEC柱轴压力提高了节点的初始转动刚度,而受力变形过程中的二阶效应降低了其抗弯承载力并加快了梁截面进入屈服的损伤进程;所有试件均表现出良好的自复位功效;所有试件破坏模式均为加强T形件端部焊缝附近梁截面形成塑性铰,更好地满足“强节点弱构件”的设计要求。上述结果有助于对PEC柱-钢梁节点抗震性能的认识,可为PEC柱-钢梁组合结构设计规范制订以及工程应用提供参考。
In order to further study the seismic behavior of the welded mid-point of the new PEC column-steel beam T-piece, considering the design parameters of the column axial pressure, the arrangement of PEC columns and the type of steel plate section, four mid-nodes were designed to be 1: 1.6 And the horizontal low-cycle reciprocating load test was carried out. The yielding or buckling of steel and the cracks and crushing of concrete in each specimen were observed and recorded, and the load-displacement hysteresis curve and failure mode of the specimen were obtained. According to the test results, the bearing capacity of specimens, the degradation of joint stiffness, energy dissipation capacity and the transmission mechanism of joints are analyzed. The results show that the prestress of the PEC column flange increases the confinement effect of the concrete in the core area. The PEC column axial pressure increases the initial rotation stiffness of the node, while the second-order effect in the deformation process reduces the flexural load Force and speed up the beam section into yielding damage process; all specimens showed a good self-resetting effect; all specimen failure modes are to strengthen the T-shaped end of the weld near the beam section to form a plastic hinge to better meet “Strong node weak component ” design requirements. The above results contribute to the understanding of the seismic behavior of PEC column-steel beam joints and provide a reference for the design of PEC column-steel beam composite structure design and engineering application.