Structural Performance of Super-Long-Span Cable-Stayed Bridges with Steel and CFRP Hybrid Cables

This paper presents an investigation of super-long-span cable-stayed bridges with hybrid cables, including steel and carbon fiber-reinforced polymer (CFRP) cables arranged in the short- and long-cable regions, respectively. Three 1600-m-span cable-stayed bridges with steel, CFRP and hybrid cables are first designed. Their static and dynamic structural performance was subsequently investigated by finite element analysis. Simulation results demonstrate that arranging CFRP cables in the long-cable regions can fully utilize the advantage of CFRP through examining their equivalent elastic modulus, load-carrying efficiency ratio and self-weight/stress ratio. The hybrid cable-stayed bridge exhibits the higher stiffness enhancement in comparison with the CFRP cable-stayed bridge. In comparison with the CFRP cables, the use of hybrid cables is able to increase the frequency for the first-order vertical mode, thus overcoming the weakness of the CFRP cable-stayed bridge in terms of stiffness. In addition, the natural frequencies of CFRP cables are much higher than the low-order vertical vibration frequencies of cable-stayed bridge, which is beneficial to reducing the probability of cable–deck coupling vibrations.