摘要
拉索作为大跨度斜拉桥的主要承重构件,横向刚度较小,在地震荷载作用下容易发生索-梁和索-塔耦合振动,对斜拉桥的能量分布和阻尼特性产生较大影响,在斜拉桥地震响应计算中有必要考虑拉索的局部振动影响。根据子结构原理和自由度凝聚的方法,在斜拉桥动力特性和地震响应分析中可以考虑拉索的局部振动,并编制了三维有限元程序,对拉索局部振动的影响进行了研究。结果表明,考虑拉索局部振动时,斜拉桥纵向振型的参与系数有不同程度的减小,主梁和桥塔的加速度、位移、弯矩和轴力增大非常显著,短索的纵向位移减小,而长索的纵向位移增大,拉索脉动张力显著增大,拉索位移和张力时程出现拉索局部振动干扰的现象。
Cable in cable-stayed bridges is flexible in transverse direction. Coupled cable-deck or cable-tower motion may occur under the excitation of earthquake which can affect the energy distribution and damping characteristics of the bridge. It is necessary to take into account the effects of local cable vibration in the seismic response analysis of cable-stayed bridges. Based on substructure and freedom condensation methods, local cable vibration can be incorporated in the dynamic characteristics and seismic response of cable-stayed bridges. A three dimensional finite element program is developed. The effects of local cable vibration on the dynamic characteristics and seismic response of cable-stayed bridge are studied. The results show that the introduction of local cable vibration leads to a decrease in the participation factors of longitudinal modes and remarkable increases in the acceleration, displacement, flexural moment and axial force of deck and tower. The displacements of short cables reduce while those of long cables increase. The dynamic cable tension magnifies. Local cable vibration phenomena are obvious in the time history of cable displacement and tension.
出处
《工程力学》
EI
CSCD
北大核心
2006年第9期157-166,共10页
Engineering Mechanics
基金
国家教育部留学归国人员科研启动基金资助
关键词
斜拉桥
地震响应
拉索局部振动
动力特性
阻尼
cable-stayedbridge
seismic response
local cable vibration
dynamic characteristic
damping
