The Behavior Of CFRP Cables In Long Span Cable Stayed Bridges Under Static And Dynamic Loads

In the past few decades,cable stayed bridges has become a preferred alternative in super span bridges because of their long-spanning ability,aesthetics and relatively simple construction methods.Stay cables are the principal structural elastic support for the girder and constitute a large construction and life cycle cost.With the rapid development of cable technology,Carbon Fiber Reinforced Polymer(CFRP)cables have become a potential substitute for steel cables because of their high ultimate strength,low density,corrosion resistance and lower linear thermal coefficient.In this study,a finite element modeling approach was adopted to investigate the static and dynamic characteristics of Carbon Fiber Reinforced Polymer cables as compared with steel cables for1008 m and 1500 m central span cable stayed bridges.The static analysis of a 1008 m and 1500 m main span cable stayed bridges with CFRP and steel cables includes dead load,vehicle load,pedestrian load and temperature load.The cable nonlinear geometric properties such as the sag effects,P-Δ effects and large deformation analysis were also investigated.The results indicate that the cable tension force of CFRP is less than the steel cables but the girder bending moment is slightly higher with CFRP cables.However,the vertical displacement of the girder is higher in CFRP cables than steel cables.In addition,the temperature load effect of the steel cables in the girder is greater than CFRP cables because of the higher linear coefficient of expansion of steel cables.The dynamic performance for the natural vibration frequency of the 1008 m and 1500 m central span cable stayed bridge for CFRP and steel cables are also analyzed.The fundamental vibration mode shape of CFRP cables is similar to steel cables.The lateral bending frequencies of CFRP are less than steel cables but the vertical vibration mode fundamental frequency of the CFRP cables is slightly higher.The torsional fundamental frequency of the CFRP cables is significantly higher than the Steel Cables.In conclusion,the structural performance of CFRP cables is higher than steel cables can be applied in long span cable stayed bridges for optimized cable efficiency.