香港汲水门大桥的模态识别  

Modal Identification of Kap Shui Mun Bridge in Hong Kong

作　　者：朱乐东[1] 张之勇[2] 张志成[2] 朱宏平[3] 

机构地区：[1]同济大学土木防灾国家重点实验室,上海200092 [2]香港科技大学土木及结构工程系 [3]华中理工大学土木工程系,武汉430074

出　　处：《振动工程学报》1999年第4期505-512,共8页Journal of Vibration Engineering

摘　　要：汲水门大桥是一座主跨430 米、双塔平行双索面、公铁两用双层斜拉桥,横跨香港马湾岛和大屿山岛之间的汲水门水道。在通车之前对该桥进行了实桥环境随机振动试验研究,以获得对桥梁抗震、抗风、健康监测、故障诊断等非常重要的结构固有模态(包括固有频率、振型及对应的阻尼比)。对主梁上的11 个测站(33 个测点)和两桥塔上的4 个测站(16 个测点)分4 组进行了环境随机振动信息的记录,并利用自编的模态识别程序EDPFDM 对所记录的信号进行了处理。在0～6Hz 范围内共识别出主梁竖向弯曲振动为主的模态10 阶,主梁横向弯曲振动为主的模态4 阶,主梁扭转振动为主的模态6 阶。经比较,固有频率和振型的试验结果与MSC-NAS-TRAN 程序的分析结果十分接近。Kap Shui Mun Bridge,crossing the KapShui Mun Channel between Mawan Island and Lantau Island,is a highway railway cable stayed bridge with a 430m main span,two H style pylons and two parallel cable planes.The ambient arbitrary vibration measurement was conducted on the bridge before its opening to obtain its eigen modes (including eigen frequencies,mode slapes and damping ratios),which are very important parameters for wind resistant and aseismic research,health monitoring and malfunctioning diagnosis of bridges.The arranged 11 survey stations (33 survey positions) on main girder,4 survey stations (16 survey positions) on two pylons were divided into 4 groups,and the ambient vibrations on the all survey positions were measured group by group.Then,the all recorded signals were reduced by using the program EDPFDM,made by the 1st author.In all,10 vertical,4 lateral and 6 torsional eigen modes of main girder were discned in the range of 0～6Hz.Finally,a good agreement is shown by the comparison between the experimental results of eigen modes and those computed with the program of MSC NASTRAN.

关 键 词：随机振动 固有模态 模态识别 公铁路两用桥 

分 类 号：U448.121[建筑科学—桥梁与隧道工程] U441.3[交通运输工程—道路与铁道工程]