Experimental study on seismic performance of a new transfer joint in the steel-concrete vertical hybrid structure

Abstract

Steel-concrete vertical hybrid structure (S-RC structure) is usually composed of upper steel and lower reinforced concrete (RC) structures. The transfer joint between them is the key part to ensure the vertical structural internal force transferring. This study proposed a new kind of joint by inserting the upper steel column into the lower RC column. To study the seismic performance of this joint, four specimens are tested under cyclic loading. The effects of axial force ratio, steel column size, and embedded depth ratio are investigated and discussed. Test results show that the failure patterns are typical beam flexural failure with plastic hinges formed at the beam ends adjacent to the corbel. All the specimens exhibited satisfied seismic performance with stable load-displacement response, excellent energy dissipation capacity and ductility. Furthermore, the increase of steel column size shows positive influence on the joint strength and stiffness, and larger axial force ratio can greatly improve the energy dissipation capacity, while increasing the embedded depth ratio only improves the strength by less than 10%. Finally, calculation methods for the bearing capacity and design suggestions on the embedded depth ratio of the steel column are both proposed for the new joint, which provide useful guidance on the design of the transfer joint in S-RC structures.