文档介绍：大跨下承式连续梁拱组合式桥自振特性研究
李青山
(中铁第五勘察设计院集团有限公司桥梁设计院,北京102600)
摘要:为准确掌握结构的动力特性,以(82+172+82)m连续梁拱组合式桥为工程背景,建立空间结构有限元模型。对桥梁自振频率、振型进行了计算分析,研究了拱肋刚度、横、斜撑刚度及其布置形式和矢跨比对连续梁拱组合式桥动力特性的影响。分析结果表明,结构面外振型较面内振型先出现,面内刚度大于面外刚度;拱肋刚度对结构自振特性影响较小;横、斜撑刚度及布置形式对结构面外基频影响较为显著,对面内基频影响不明显;结构面外基频随矢高的增加而减小。
关键词:连续梁拱组合式桥;自振特性;拱肋;横、斜撑;矢跨比
Self-vibration Characteristics Research of Long-span Continuous Through posite Arch Bridge
Li Qing-shan
(Bridge Department of China Railway Fifth Survey And Design Institute Group Co., Ltd., Beijing 102600)
Abstract: In order to obtain the dynamic characteristics of the structure exactly, the (82+172+82) m continuous through posite arch bridge was simulated by using MIDAS. Self-vibration frequencies, mode shapes were calculated and analyzed. Impacting on the self-vibration characteristics, more factors were researched, such as arch rib stiffness, arranging and the stiffness of the transverse and inclined brace, rises-pan ratio. The results indicated that out-plane vibration mode of the structure appeared earlier than in-plane vibration mode and the dynamic characteristics of the structure were influenced by the arc rib stiffness slightly. It also suggested that the stiffness and arranging of the transverse and inclined brace impacted on the out-plane frequency obviously and on the in-plane frequency slightly. At the same time, the out-plane frequency decreased with increasi