纤维增强材料-混凝土-钢组合矩形空心柱的低周往复荷载试验研究

Experimental Research on Seismic Properties of Rectangular FRP-Concrete-Steel Double-Skin Tubular Columns Under Quasi-Static Load

纤维增强复材(FRP)-混凝土-钢管组合空心柱由FRP外管、钢内管和两者之间填充的混凝土组成,具有良好的抗震性能和耐腐蚀性能。现有研究主要集中在圆形截面组合空心柱和方形截面组合空心柱,而针对矩形截面组合空心柱的研究较少。矩形截面组合空心柱可根据工程需要,合理设计截面的长边与短边之比,以提供绕两对称轴不同的抗弯刚度。通过对3个矩形FRP-混凝土-钢组合空心柱在恒定轴压和侧向往复荷载下的抗震性能试验,参数包括FRP厚度和水平侧向荷载的加载方向(即绕矩形截面的强轴或弱轴施加弯矩),该组合柱的长边和短边分别为300 mm和200 mm,总高度为2 150 mm,研究表明:具有较厚FRP管的试件的承载力较高;绕强轴加载的试件的承载力和延性远高于绕弱轴加载的试件;基于OpenSees建立的数值模型对滞回曲线的预测略偏保守。

FRP-concrete-steel double-skin tubular columns(DSTCs), which consist of an outer FRP tube, an inner steel tube and the concrete infilled between the two tubes, have excellent seismic performance and anti-corrosion performance. Existing studies on DSTCs focused on specimens with a circular cross-section or a square cross-section, while specimens with a rectangular cross-section are rarely investigated. According to engineering needs, the rectangular aspect ratio could be designed optimally for rectangular DSTCs to provide different bending stiffness around two axes of symmetry. 3 rectangular DSTCs were tested under constant axial compression and lateral cyclic loading to assess their seismic performance, and the parameters included the FRP thickness and the lateral loading direction(i.e., bending around the strong axis or the weak axis of the rectangular cross-section). Rectangular DSTCs in the present study had a length of 300 mm and a width of 200 mm for the cross-section, and a total height of 2 150 mm. The results indicated that the specimen with a thicker FRP tube had a larger bearing capacity;the specimen loaded around its strong axis had better bearing capacity and ductile than the corresponding specimen loaded around its weak axis;the predictions for the experimental hysteretic curves by numerical model based on OpenSees were slightly conservative.