动水对斜拉桥结构动力响应影响研究  

Study of the effect of hydrodynamic force on cable-stayed bridges under earthquake

作　　者：李悦[1] 宋波[1] 

机构地区：[1]北京科技大学,北京100083

出　　处：《土木工程学报》2010年第12期94-99,共6页China Civil Engineering Journal

基　　金：国家自然科学基金重大研究计划(90715007)

摘　　要：深水大跨径斜拉桥在地震荷载作用下,桥梁水下部分与周围水体之间相互作用必然导致斜拉桥受到水体运动产生的动水力的作用。在已有Morison动水理论的基础上提出了一种适用于深水大跨径斜拉桥动力时程反应分析的动水力简便计算方法,并应用于南京长江第三大桥,分析了动水对斜拉桥结构的动力特性和地震反应的影响。研究发现:水与斜拉桥下部结构相互作用会使斜拉桥自振频率有所减小,其中第一阶自振频率相对无水时减小了8.24%;地震作用下动水对斜拉桥结构各个构件地震动力反应都有显著的影响,使主梁弯矩最多增大了7.73%,最不利桩位底部弯矩增大了14.22%。在深水斜拉桥结构进行抗震设计中,动水对斜拉桥动力响应的影响不容忽略。When deep-water long span cable-stayed bridges are under seismic loads,the interaction between underwater structures and the surrounding water will inevitably lead to hydrodynamic forces on the bridges.Based on the Morison hydrodynamics theory,a simplified method for calculation of hydraulic force was proposed,adapting to time-history response analysis of cable-stayed bridges.Taken the Nanjing Yangtze River No.3 Bridge as a prototype,the hydrodynamic effects were analyzed.The main results include： 1） The natural vibration frequency of the cable-stayed bridge was decreased due to the interaction between water and substructure in deep water.2） The predominant frequency was reduced by 8.24% relative to no water condition.3） In earthquake,the effect of hydrodynamic force on the dynamic response of the elements in the cable-stayed bridge structure was significant,with the moment of the main beam being increased by 7.73% and the bottom moment of the most unfavorable pile being increased by 14.22%.4） In the seismic design of deep-water cable-stayed bridges,the effect of hydrodynamic force should not be ignored.

关 键 词：深水桥梁 斜拉桥 动水力 动力反应 

分 类 号：U442.59[建筑科学—桥梁与隧道工程]