【摘要】 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。更多还原

【Abstract】 The research conducted quasi-static tests on three 6 m-span steel spatial arch truss with 0.2,0.3 and 0.4rise to span ratios respectively under vertical cyclic loading,and analyzed the failure process and failure mechanism of the trusses to obtain the hysteretic curves,skeleton curves,energy dissipation,ductility performance and stiffness deterioration of trusses.The results show that the failure of arch truss specimens starts with micro cracks of perpendicular insertion weld for the maximum tensile member and lower chord which is in the biggest force internode.Then local crack gradually forms in the region,finally the members of this region break,causing the truss to become a geometrical mechanism and collapse.A few members develop plastic state when the structure lose bearing capacity,therefore their overall deformation is not obvious and their energy consumption is normal.The members and nodes entering the plastic state generate cumulative damage,which leads to low-cycle fatigue failure.更多还原