State-of-the-art of bridge composite structures in China

The composite structures have experienced a significantly increasing application in China, in which the steel-concrete composite structure is the most widely used, and the concrete composite structure is applied more and more. This paper reviewed briefly the development history of composite structure in bridge engineering in the last seven decades, introduced the state-of-the art of composite structures including the beams, columns and arches, and presented some discussions. It can be found that the traditional steel-concrete composite structures, such as steel beam-concrete deck slab, and concrete-filled steel tube (CFST) arch bridge, have been applied continuously and studied in-depth, and the corresponding design theory system is constantly improved. At the same time, the new composite structures such as corrugated steel web (truss rod)-concrete composite beams, CFST composite beams, hybrid girders in the cable-stayed bridges, CFST piers and pylons, Melan arches, etc., have been developing rapidly. Nevertheless, certain novel configurations exhibit insufficient evaluation of constructability and lifecycle costs. Some research results and technical experience have not been fully reflected in the relevant specifications, and need to be supplemented and improved in the future revision of the specifications. The behaviors and performance of steel-concrete composite structures lies between that of steel structures and concrete structures. In research and application, they may be understood better by tracing back the origination of structures. For some composite structures with same components, their performances may also have quite large difference due to the contribution of each component. For concrete composite structures consisting of different concrete materials, the degree of the difference in material properties is a structure that should be considered as a concrete composite structure and also a problem that needs further research. In engineering, it is commonly to strengthen or stiffen a structure locally, hybrid structures should be distinguished from it.