Seismic Performance Analysis Of The Super-span Suspension Bridge With CFRP Cables

In the new century，the study of more than2000m level super-span suspension bridge,particularly the application of new materials in super-span suspension bridge, is attached thegrowing importance to designer today. As super-span bridge structure is flexible，its effects ofgeometric nonlinear are becoming more obvious. The dynamic characteristics and earthquakerespounce are becoming more complex，therefore it becomes essential to carry out theresearch in this field.The dynamic characteristics and the seismic performances of thesuspension bridges with CFRP cables and the suspension bridges with steel cables arecomparatively studied in the paper.The general situation of suspension bridges is introduced,includingthehistory,development,structure, characteristic the new challenges. the merits and faults ofthe CFRP materials is Elaborated.The dynamic performances, including the natural vibration frequency and vibrationmodes of the2000m-span suspension bridges with CFRP cables and steel cables are analyzedbased on the finite-element method. The fundamental vibration mode shapes of suspensionbridges with CFRP cables are similar to those of the suspension bridges with steel cables. Thelateral vibration frequencies of the suspension bridges with CFRP cables are slightly largerthan those of the suspension bridges with steel cables,.The torsional vibration fundamentalfrequencies of the former are significantly higher than those of the later, so the stability of theformer is better.The earthquake response of the2000m-span suspension bridges with CFRP cables andsteel cables is analyzed based on the response spectrum method and time-history analysismethod,and the results are compared between the two methods. The differences between thedisplacement and internal force are analyzed, the seismic performance of the suspensionbridges with CFRP cables is better than the suspension bridges with steel cables, The verticalstiffness of the suspension bridges with CFRP cables decrease, resulting in the increase ofthe internal force.Finally,the commonly used seismic isolation devices are introduced, including thelead-rubber bearings and viscous dampers. Their classification, characteristics and thetheoretical analysis and calculation model are introduced too.