考虑加载制度影响的狗骨式连接钢框架子结构抗震性能试验研究

为研究加载制度对狗骨式连接钢框架结构变形能力及累积耗能能力的影响，设计了5榀单跨狗骨式连接钢框架子结构，对其进行单向加载、等位移循环加载、标准加载及近场地震动作用下的拟静力试验。结果表明：所有框架出现的塑性铰均在钢梁端部的翼缘削弱位置，避免了钢梁端部焊缝的过早脆性断裂；狗骨式连接钢框架结构滞回曲线饱满、变形能力及延性性能优良。此外，加载制度对狗骨式连接钢框架子结构的层抗侧刚度、水平承载力退化、极限变形能力及累积耗能能力均有显著影响。等位移循环时，加载位移幅值越小，狗骨式连接钢框架子结构的层抗侧刚度及承载力退化越趋于缓慢，其层间累积延性系数及等效能量耗散系数越大。

Experimental investigation on seismic behavior of steel frame substructure with RBS connections considering loading protocol

To investigate the influence of loading protocol on the deformability and cumulative energy dissipation capacity for steel frame with reduced beam section (RBS) connections, a total of five single span steel frame substructure with RBS connections were fabricated and tested under different loading protocols, including monotonic loading, equal displacement cyclic loading, standard loading and near-fault loading protocol. The test results show that all of the plastic hinges of these specimens occurr at the location of the reduced flange at steel beam ends, and the fracture failure of weld connected steel column and steel beam is avoided. The steel frame with RBS connection possesses full hysteretic curve, excellent deformability and energy dissipation. In addition, the loading protocol has significant influence on the inter-story lateral stiffness, the degradation of lateral load, ultimate deformability, and cumulative energy dissipation. Under the loading condition of equal displacement, the inter-story lateral stiffness and lateral loading capacity of steel frame with RBS connections degrade slowly with the decrease of loading displacement, but the inter-story cumulative ductility and the equivalent energy dissipation ratio show the increasing tendency.