大跨度斜拉桥动力反应分析
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摘要
以主跨460 m的武汉军山长江大桥为例,运用自编程序进行了成桥状态索力计算,并详细分析了其动力特性。结果表明:1)该桥第一振型为纵飘振型,这对结构在地震作用下的反应十分有利;2)其模态相当密集,自振频率很低,前40阶模态的频率在0.1—2 Hz之间,从而使得桥梁具有良好的使用性能;3)结构的扭转频率和弯扭频率比ε值较高,说明该桥具有较高的颤振临界风速,具有较好的抗风性;4)大跨度斜拉桥支座连接方式对整个桥梁体系的动力特性影响很大,必须正确模拟;5)在半漂浮体系斜拉桥中,对塔的横向地震反应贡献最大的是以塔的振动为主的振型。该桥计算分析结论可为该类型大跨度斜拉桥的抗震分析和设计提供参考依据。
Take the Wuhan Junshan Yangtze River Bridge as a example,whose main-span is 460 m,the cable force of completed bridge were calculated by the self-developed program,and the dynamic character of it was analyzed.The results show that: 1) Its first mode of vibration is longitudinal floating mode,which is favorable to the earthquake-response of structures.2) Its former 40 rank frequency are located between(0.1~2) Hz which is avail to the condition of traffic condition.3).The ratio of torsion and bending-torsion frequency is 2.04 which is very high.It indicates the flutter critical wind velocity is high and the windproof performance of this bridge is good.4) The dynamic responses are sensitive to the connection mode which should be simulated correctly.5) In this kind of half-floating cable-stayed bridge,the vibration of the tower contributes most to the transverse seismic response of the tower.The conclusion can give a reference to the seismic analysis of this kind of bridge.
Take the Wuhan Junshan Yangtze River Bridge as a example,whose main-span is 460 m,the cable force of completed bridge were calculated by the self-developed program,and the dynamic character of it was analyzed.The results show that: 1) Its first mode of vibration is longitudinal floating mode,which is favorable to the earthquake-response of structures.2) Its former 40 rank frequency are located between(0.1~2) Hz which is avail to the condition of traffic condition.3).The ratio of torsion and bending-torsion frequency is 2.04 which is very high.It indicates the flutter critical wind velocity is high and the windproof performance of this bridge is good.4) The dynamic responses are sensitive to the connection mode which should be simulated correctly.5) In this kind of half-floating cable-stayed bridge,the vibration of the tower contributes most to the transverse seismic response of the tower.The conclusion can give a reference to the seismic analysis of this kind of bridge.
引文
1中交公路规划设计院.京珠国道主干线武汉军山长江公路大桥施工图.北京:1999
2 Nazmy A S,Abdel-Ghaffar A M.Non-linear earthquake-response ofLong-span cable-stayed bridges:theory.Earthquake Eng Struct Dyn,1990;19:45—62
3 Fleming J F.Nonlinear static analysis of cable-stayed bridge.Com-puters and Structures,1979;10:621—635
4张海龙.桥梁结构分析与程序设计.武汉:华中理工大学出版社,1995
5范立础.桥梁抗震.上海:同济大学出版社,1997
6苏成,韩大建,王乐文.大跨度斜拉桥三维有限元动力模型的建立.华南理工大学学报(自然科学版),1999;27(11):51—56
7徐凯燕.大跨度斜拉桥非线性地震反应时程分析及减、隔震研究.广州:华南理工大学,2009
2 Nazmy A S,Abdel-Ghaffar A M.Non-linear earthquake-response ofLong-span cable-stayed bridges:theory.Earthquake Eng Struct Dyn,1990;19:45—62
3 Fleming J F.Nonlinear static analysis of cable-stayed bridge.Com-puters and Structures,1979;10:621—635
4张海龙.桥梁结构分析与程序设计.武汉:华中理工大学出版社,1995
5范立础.桥梁抗震.上海:同济大学出版社,1997
6苏成,韩大建,王乐文.大跨度斜拉桥三维有限元动力模型的建立.华南理工大学学报(自然科学版),1999;27(11):51—56
7徐凯燕.大跨度斜拉桥非线性地震反应时程分析及减、隔震研究.广州:华南理工大学,2009
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