The cables behavior of long-span suspension bridge with CFRP cable system during erection

The weakness in corrosion resistance and low load-carrying efficiency of steel cables have become the obstacles to the development of suspension bridge with longer spans. The CFRP (Carbon Fiber Reinforced Polymer) with special characteristics, such as light weight and excellent corrosion resistance, shows great advantages for the cable system of longer suspension bridge. In this paper, calculation methods for the key cable parameters including cable saddle pre-bias, the sag of cable, the coordinate of cable clamps in free-cable stage are investigated analytically, and a calculation program for these parameters is compiled with MATLAB and FORTRAN. Then, two types of suspension bridge with the main span of 2000m to 5000m, with CFRP cable system and steel cable system respectively are designed and taken as numerical examples. The numerical analysis results indicate that the cable saddle pre-bias and the variation of cable sag will increase obviously throughout the bridge erection if steel cable system was replaced with CFRP cable system, which may bring some new construction and design problems. Further discussion based on the results shows these cases should owe to the reduction of the self-weight and the elastic modulus of CFRP cables.