香港汀九大桥自振特性测量

香港汀九大桥是一座三塔四索面的特大斜拉桥,结构新颖.为了进行更准确的抗风抗震分析,以及将来桥梁的健康检测,实验测量桥梁的自振特性是必不可少的.根据汀九大桥环境激励(主要是风)下桥振动的加速度传感器数据,利用谱分析方法来确定振型及对应的固有频率,通过半功率带宽法测得阻尼比.振型及对应的固有频率与有限元分析结果基本吻合.

Modal Identification of the HK Ting Kau Bridge

HK Ting Kau Bridge is a long span cable-stayed bridge with unique features. It has three single-legged towers and four inclined planes of cables. For the advanced analysis and health monitoring of the bridge, the vibration characteristics of the structure must be measured. This paper introduces how to measure and determine the vibration characteristics, such as natural frequencies, corresponding mode shapes and damping ratios. Based on the ambient vibration method, 9 vertical bending modes, 5 lateral bending modes and 4 torsion modes as well as the corresponding natural frequencies and damping ratios are given. The results agree with those of 3D finite element analysis. And in this paper, the damping ratios determined by high resolution power spectrum and those by linear interpolation of low resolution power spectrum are compared. The linear interpolation method works well.