GFRP管–钢骨混凝土纯弯构件的滞回性能研究

Study on Hysteretic Behavior of Steel-Encased Concrete Filled GFRP Tubes Pure Bending Members

摘要: 本文以9根GFRP管–钢骨混凝土组合构件为研究对象，考虑混凝土强度、GFRP管厚度、钢骨型号和加载方向，对GFRP管–钢骨混凝土纯弯构件的滞回性能进行试验研究，分析其破坏形态、滞回曲线和骨架曲线特征，研究组合构件在低周往复荷载作用下的刚度退化、强度退化和耗能等抗震性能指标；建立组合构件滞回模型，在验证模型正确性的基础上，对其滞回工作机理进行分析。试验结果表明，GFRP管、钢骨、混凝土三者协同工作，且GFRP管和混凝土表现出良好的粘结性能，可以有效地传递应力；构件的受力过程可分为弹性阶段、弹塑性阶段和强化阶段；构件承载力随型钢型号的增加而增大，型钢型号较小的构件其刚度退化较为明显；强轴加载构件初始刚度较大，刚度退化较快；构件承载力随混凝土强度的增加而增大，且混凝土强度较高的构件刚度退化较快；构件承载力和刚度随GFRP管厚度的增加而增大，且GFRP管厚度较大的构件其刚度退化较快。

Abstract: In this paper, 9 steel-encased concrete filled GFRP tubes composite members are used as the research object and the hysteretic performance of pure bending members is tested. The test variables are concrete strength, thickness of GFRP tubes, I-steel type and loading direction. The failure mode, hysteresis curve and skeleton curve of pure bending members are studied, and Seismic performance indexes such as stiffness degradation and strength degradation of the composite member under low-cycle load are analyzed. The simulated mode of pure bending member is established. The working mechanism of composite member is analyzed. The test results show that GFRP tubes, I-steel and concrete work together. It shows good bonding properties between GFRP tubes and concrete, which can effectively transfer stress. When strong axial of the pure bending member is loaded, the hysteresis curve of the member shows a relatively full spindle shape. When the weak axis of the pure bending member is loaded, the hysteresis curve of the component is not full and the pinch is obvious. The force process of the member can be divided into the elastic phase, the elastoplastic phase and the strengthening phase. The bearing capacity of the component increases with I-steel type. The stiffness degradation of the components is more obvious; the initial stiffness of the components loaded with strong axis is larger, and the stiffness degrades quickly; the bearing capacity of the components increases with the increase of the concrete strength, and the stiffness of the components with higher concrete strength degrades faster; the bearing capacity and the stiffness of the components increase with the thickness of the GFRP tubes, and the stiffness of the component with a larger GFRP pipe degrades faster.