Challenge and Innovation of Long Span Bridges in China and over the World

The challenges and achievements of long span bridges in girder, arch, cable-stayed and suspension types are briefly introduced as the background of bridging capacity innovations in China and over the world. The challenging problems encountered in girder bridges are related to extreme bending moment, PC girder excessive deflection and orthotropic steel deck cracking, and the corresponding innovative techniques include hybrid structures, corrugated steel webs or steel truss webs composite girder and steel-UHPC composite deck. The most recent achievements of arch bridges can be attributed to steel box arch ribs for maintenance convenience and life-cycle durability and concrete- filled-steel-tube arch ribs for saving steel and concrete consumption and construction costs. The current cable-stayed bridge types with spatial cable planes and closed box girder have supported to enlarged span length up to 1,400 m or 1,500 m in near future if the challenging problems of deck lateral bucking and stay cable vibration can be overcome. Suspension bridges have been identified with the most challenging problem to have super long span length, and one of three kinds of control measures, including stabilizers, slot and the combination of slot and stabilizer, has to be adopted for aerodynamic stability. For suspension bridges with multiple or at least double main spans, the most important design concept is to select the proper longitudinal bending stiffness of the central pylon.