Abstract
The connection in mixed structures, consisting of different types of members, has been a complicated technical issue for hybrid structures and the structural design for connection is rather conservative. The newly developed connection is a simple structure, which is a concrete-filled steel box (CFSB) structure. The connecting members, such as a beam and a column, of CFSB are simply inserted into the steel box. No shear connectors or steel reinforcement are necessary in CFSB at all, making the construction time and cost less. This paper presents the load-carrying capacity under axial force, bending and shear of the CFSB connection through laboratory tests and 3D finite element analyses. The results show high strength and ductility due to the good confinement effects of the steel box on the filled concrete. The paper also introduces briefly the first practical application of the CFSB connection to a highway bridge in Sapporo, Japan.