应用碳纤维索的斜拉桥地震响应分析

以在建的杭州湾跨海大桥北航道桥为对象,采用强度等效的原则将原桥的钢丝索替换成碳纤维索,利用能考虑拉索局部振动的斜拉桥地震响应分析程序,分析比较了同一地震荷载作用下碳纤维索斜拉桥与钢丝索斜拉桥的振动特性及地震响应差异,并探讨了引起差异的根本原因。结果表明:索桥耦合振动是引起两种拉索斜拉桥的振动特性和地震响应存在差异的根本原因,碳纤维索的自振频率高,发生索桥耦合振动的可能性低于钢索斜拉桥,同一地震荷载作用下碳纤维索斜拉桥的地震响应要较钢丝索斜拉桥有不同程度的降低。

SEISMIC RESPONSE ANALYSIS OF CABLE-STAYED BRIDGES USING CARBON FIBER COMPOSITE CABLE

The difference of dynamic characteristics and seismic responses between cable-stayed bridges with steel and carbon fiber composite (CFRP) cables was studied and the essential reason was investigated, taking the northern channel bridge of Hangzhou bay as an object. The steel cables were replaced with CFRP cables using strength equivalent principle and the program for seismic response calculation considering cable lateral vibrations was employed. The results show that coupling vibration between bridge and cables is the essential reason inducing the difference of dynamic characteristics and seismic responses between the bridges with two kinds of cables. The frequencies for free vibration of CFRP cables are higher, so the possibility of cable-bridge coupling vibration is smaller than that of steel cables. The seismic responses of cable-stayed bridges with CFRP cables are lower than that of steel cables under the same seismic loadings.