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通过3个跨度为6 m、矢跨比分别为0.2、0.3、0.4的钢管拱桁架结构试件在竖向循环荷载作用下的拟静力试验,分析结构的失效过程和破坏机理,研究结构的滞回曲线、骨架曲线、耗能能力、延性性能和刚度退化等抗震性能。结果表明:钢管拱桁架试件的失效始于受力最大节间最大受拉腹杆与下弦杆相贯焊缝处的微裂纹,而后逐步形成该区域的局部开裂,最后在该区域发生断裂并形成机构而破坏;结构失效时只有少部分杆件进入塑性工作状态,试件的整体变形不大,耗能能力一般;进入塑性工作状态的杆件和节点产生的累积损伤导致结构发生低周疲劳断裂破坏。
The quasi-static tests of three arch bridges with arch span of 0.2, 0.3, 0.4 with span-span ratios of 6 m and vertical span under vertical cyclic loading are carried out to analyze the failure process and failure mechanism of the structure. Hysteresis curves, skeleton curves, energy dissipation, ductility and stiffness degradation. The results show that the failure of the steel arch truss specimens begins with the micro-cracks at the maximum joint between the tension web and the lower chord at the maximum internals of the steel tube, and then gradually forms the local cracking in this area and finally breaks down in this area Forming a mechanism and destroying; when the structure fails, only a few of the rods enter into the plastic working condition, the overall deformation of the test piece is not large, and the energy-consuming ability is general; the cumulative damage caused by the rods and nodes entering into the plastic working condition causes the low-cycle fatigue of the structure Fracture damage.