Abstract: Three combined specimens are experimentally studied and analyzed by FEM. Compared with the corresponding single members, it is clearly proved that the combination effects, with different combination forms, significantly improve the performance of members according to the observed enhancement in bearing capacity, stiffness and ductility. In addition, the buckling behavior and destruction mechanism are investigated, and the characteristics and mechanism of thin-walled member’s destruction under static and hysteretic loads are discussed. The following conclusions can be made: the combination effects improve the static performance, which is influenced by the combination form; Failure under static force is caused by the buckling of sideway supports; The degradation of hysteretic performance is mainly because of the plastic local buckling.