为获悉半刚性钢管混凝土框架结构在地震作用下的抗震性能和破坏机理,进行2榀两层单跨钢管混凝土柱与钢梁单边高强螺栓端板连接框架试件的拟静力试验,包括1个圆形和1个方形钢管混凝土框架。研究柱截面类型和端板类型对框架破坏形式和抗震性能的影响。详细地观察了框架在低周反复荷载作用下的受力全过程和破坏特征,分析此类结构的滞回曲线、骨架曲线、强度和刚度退化规律、耗能能力等抗震性能指标,并结合现有规范评价结构的延性。试验结果表明,此类半刚性连接钢管混凝土框架结构具有良好的滞回性能和耗能能力,其延性系数μ=2.41—3.75,能量耗散系数E=0.823—0.955;在柱截面含钢率相同条件下,方钢管混凝土框架试件的极限承载力和耗能能量均高于圆钢管混凝土框架试件;梁柱节点采用单边高强螺栓端板连接具有典型的半刚性特征,连接可靠和耗能效果好。研究成果将为我国装配式组合结构设计理论与应用提供科学依据。
In order to investigate the seismic behavior and failure mechanism of semi-rigid concrete-filled steel tubular (CFST) frames with endplate connections under pseudo-static loading, two two-layer one-span specimens of blind bolted endplate connected frames between CFST columns and steel beams were conducted. The test specimens included one circular CFST frame and one square CFST frame. The influence of column section type and the end plate type on the frame failure modes and seismic performance were studied. The whole loading progress and failure characteristics of two specimens under low cycle loading were discussed. The hysteretic curves, skeleton curves, degradation curves of strength and stiffness, and the energy dissipation capacity were also analyzed. The ductility was evaluated according to the description of present specifications. The test results show that the semi-rigid CFST frames with high-strength blind- bolted endplate connections have good hysteretic behavior, ductility and energy dissipation. The ductility coefficient/x is between 2.41 and 3.75. The energy dissipation coefficient is between 0. 823 and 0.955. Under the same steel ratio of the column section, the ultimate bearing capacity and energy dissipation of square CFST frame were higher than those of circular CFST frame. The proposed high-strength blind-bolted endplate connections, which performed typical semi-rigid behavior, show reliable connection and excellent seismic performance. The research results can lay foundation for design theory and application of the fabricated composite structures.