摘要
为了深入研究大跨度多塔悬索桥的动力特性,基于ANSYS软件建立了某大跨度四塔悬索桥的三维有限元模型,采用Block Lanczos法进行模态分析,以获得该桥的自振频率和振型,并分析了主缆矢跨比、恒载集度、主梁刚度以及中塔刚度等结构关键参数对其动力特性的影响.结果表明:该桥基频为0.071 71 Hz,对应振型为主梁一阶正对称侧弯;增大矢跨比有利于提高大桥颤振性能;随着恒载集度的增加,结构各阶自振频率均有不同程度的下降;增大主梁横向和扭转刚度可分别提高主梁侧弯和扭转频率,而增大主梁竖弯刚度对主梁竖弯频率影响较小;主梁一阶竖弯频率随着中塔纵向刚度的增大而显著提高.研究结果可为大跨度多塔悬索桥的结构设计与动力分析提供参考.
To investigate the dynamic characteristics of long-span multi-tower suspension bridges,the three-dimensional finite element model for a long-span quadruple-tower suspension bridge is established by ANSYS. Modal analysis is carried out by using the Block Lanczos method to obtain the natural frequencies and the mode shapes of the bridge. And the effects of the key structural parameters,including the sag-to-span ratio,the dead load,the stiffness of the main girder,and the rigidity of the mid-pylon,on the dynamic characteristics are analyzed. The results indicate that the fundamental frequency of the bridge is 0. 071 71 Hz and the corresponding vibration mode is the first symmetric lateral bending mode of the main girder. The increase of the sag-to-span ratio can improve the flutter performance. With the increase of the dead load,the natural frequencies decrease with different degrees. When the lateral stiffness and the torsional stiffness of the main girder increase,the lateral vibration frequencies and the torsional vibration frequencies increase,respectively. However,the vertical stiffness of the main girder has little influence on the vertical vibration frequencies. The first vertical vibration frequency increases significantly with the increase of the longitudinal rigidity of the mid-pylon. The research results can provide reference for the structural design and dynamic analysis of long-span multi-pylon suspension bridges.
出处
《东南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2016年第3期559-564,共6页
Journal of Southeast University:Natural Science Edition
基金
国家自然科学基金资助项目(51378111
51578151)
关键词
四塔悬索桥
动力特性
参数敏感性
有限元分析
quadruple-tower suspension bridge
dynamic characteristic
parameter sensitivity
finite element analysis