Experimental study on ultimate strength of concrete filled double tubular steel with shear connector

Concrete Filled Tubular steel (CFT) member, which represents a superb deformability due to well-known confined effect between steel tube and concrete, has been used mainly as bridge pier. As a progressive composite member, Concrete Filled Double tubular steel (CFDT), which is consist of double skin steel tubes and filled concrete between them, has been proposed. Although a lot of reports on mechanical characteristics of the CFDT member are presently published, the necessity of shear connector for the CFDT member has not been addressed. In this research, the shear connector was installed at the interface between tubes and concrete in the CFDT member. To investigate the effect of the shear connector on the bending characteristics, the four points bending test were carried out. The results show that integrating the steel tubes and concrete enhances its bearing capacity. Furthermore, the strains of outer and inner tubes were also discussed in this paper.