中文摘要：

在方钢管混凝土管壁内设置纵向加劲肋可提高其管壁的稳定性。采用有限元软件ABAQUS对带肋方钢管混凝土柱偏心受压荷载．变形全过程关系进行计算，计算得到的破坏形态和荷载一变形关系曲线与试验结果符合较好。在此基础上，通过典型算例从变形情况、荷载一变形全过程曲线、核心混凝土的纵向应力分布以及钢管与混凝土相互作用四个方面对带肋方钢管混凝土的工作机理进行分析，并且与相应的无肋方钢管混凝土进行对比。研究结果表明：加劲肋的设置可以增加钢管约束支撑点，减小鼓曲的横向变形值，增强核心混凝土与管壁之间的相互作用，进而有效地延缓构件局部屈曲，改善管壁的稳定性，提高构件的极限荷载；纵向加劲肋宽度越大，构件极限荷载越高，后期延性越好；加劲肋宽度设置应控制在一定范围，能获得较好的综合经济效果。

英文摘要：

＇Longitudinal stiffeners＇ as a construction measure to concrete-filled square steel tubular columns are effective in enhancing the stability of thin-walled tubes. The load-deformation relationships of concrete-filled stiffened square steel tubes subjected to eccentric compression were analyzed by using the finite element software, ABAQUS. The numerical results of failure mode and load-deformation relationship were in good agreement with test data. The mechanism of the composite columns was analyzed in four aspects： deformation, load-deformation relationship, vertical stress distribution in core concrete, and interaction between steel and concrete, and then compared with the mechanism of non-stiffened concrete-filled square steel tubes. The study result shows that vertical stiffener can increase the constraint support point of the tubes, reduce the lateral deformation of buckling and enhance the interaction between concrete and steel, and thus delays local buckling and improves the stability of the steel tubes, and enhances the bearing capacity of the specimens. The larger the longitudinal stiffener width, the higher the ultimate load and the better the upper ductility.