Carbon Fiber Reinforced Polymer Cables: Why? Why Not? What If?

Cables of suspended structures are suffering due to increased corrosion and fatigue loading. Since 1980, EMPA and BBR Ltd. in Switzerland have been developing carbon fiber-reinforced polymer (CFRP) parallel wire bundles as cables for suspended structures. The excellent properties of those bundles include corrosion resistance, very high specific strength and stiffness, superior equivalent moduli and outstanding fatigue behavior. An anchoring scheme produced with gradient materials based upon ceramics and epoxy is described. For the first time, large CFRP cables were applied in 1996 on the vehicular cable-stayed Stork Bridge with 124 m span in Winterthur, Switzerland. The performance of these cables and later applications was and still is monitored with sophisticated fiber-optical systems. Up to date, these results are fully matching the high expectations. Under the assumptions that (1) the behavior of the pilot applications of CFRP cables described in this paper will be further on fully satisfactory, (2) active systems for distributed mitigation of wind-induced vibrations are going to be successful and (3) there is a need for extremely long-span bridges to cross straits like that of Bab el Mandeb, Messina, Taiwan or Gibraltar, why should the next generation of structural engineers not use CFRP cables for such extremely long-span bridges? This would open spectacular new opportunities.