内配型钢方钢管混凝土构件压弯剪性能研究

为研究内配型钢方钢管混凝土构件压弯剪复合受力工作机理，完成10个内配型钢方钢管混凝土试件的压弯剪试验研究，考虑剪跨比、轴压比和型钢截面形式对构件承载力和破坏模式的影响。运用有限元对试验结果进行模拟，针对典型算例进行受力机理分析，并对影响水平承载力的不同因素进行参数分析和评估。结果表明：内配型钢方钢管混凝土压弯剪试件表现出良好的延性行为，钢管在受压侧产生明显的鼓曲变形，型钢与内部混凝土发挥着共同作用；弱轴加载试件的水平承载力比强轴加载试件平均降低13%，设置加劲肋后构件的水平承载力平均提高21%；整个加载过程中轴向荷载发生重分布，混凝土承担的水平荷载和轴向荷载最多；型钢与混凝土的相互作用力分布不均匀，受压区型钢翼缘与混凝土的相互作用更强。保持轴压比不变，当剪跨比小于0.8时，构件的水平承载力随着剪跨比的减小大幅提高；当轴压比不超过0.4时，轴力的存在可以提高构件的水平承载力。

Mechanical behavior of square steel-reinforced concrete-filled steel tubular#br# (SRCFST) members under compression-bending-shear loads

To study the working mechanism of square steel-reinforced concrete-filled steel tubular (SRCFST) members under combined compression-bending-shear loads, a total of 10 square SRCFST specimens were tested. The influence laws of shear-span ratio, axial compression ratio and profiled steel section form on the horizontal capacity and failure modes of specimens were considered. The finite element analysis (FEA) model was established to simulate the testing results and employed to analyze the mechanical behaviors of typical specimen and subsequently the effects of various factors on the horizontal capacity were evaluated. The results showed that the SRCFST members exhibited good ductility, obvious buckling deformation appeared at the compressive side of the steel tube, and the combined effect between the profiled steel and core concrete was found. With the loading directions varying from strong axis to weak axis, an average decrease of 13% on the horizontal capacity of specimens was observed. After setting the stiffeners, the horizontal capacity of specimens increased with an average rate of 21%. During the loading process, the axial load redistributed, and most horizontal and axial loads were carried by the concrete. The interaction force between the profiled steel and the concrete was uneven, and a stronger interaction between the flange of profiled steel and the concrete occurred at the compression zone. Keeping the axial compression ratio constant, when the shear-span ratio was below 0.8, the horizontal capacity of specimens was significantly enhanced as the shear-span ratio decreased. When the axial compression ratio was less than 0.4, the horizontal capacity of SRCFST specimens was improved due to the existence of axial force.