Analysis of the dynamic characteristics of a suspension bridge based on RTK-GNSS measurement combining EEMD and a wavelet packet technique
Analysis of the dynamic characteristics of a suspension bridge based on RTK-GNSS measurement combining EEMD and a wavelet packet technique
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DOI：
10.1088/1361-6501/aacb47
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发表时间：
2018-08-01
影响因子：
2.4
通讯作者：
Xiong, Chunbao
中科院分区：
文献类型：
--
作者：
Niu, Yanbo;Xiong, Chunbao
为了研究自锚式悬索桥（即天津富民大桥）的动力特性，采用实时运动学全球导航卫星系统（RTK-GNSS）来获得结构的位移响应。针对RTK-GNSS定位精度的缺陷，首次提出了集合经验模态分解（EEMD）和小波包（WP）分析相结合的方法（EEMDWP）来提高振动信号的精度。随后，应用快速傅立叶变换和随机递减技术来估计结构的固有频率和相应的阻尼比。同时，为了对比现场测量结果，建立了结构的有限元模型（FEM）。最后，分析结果表明：（1）RTK-GNSS技术是大跨桥梁变形监测的有力工具； (2) 所提出的 EEMDWP 方法被证明优于单一 EEMD 或 WP 方法； (3)成功获得结构动力参数（即第一固有频率：0.5873 Hz，对应阻尼比：2.12%）； (4) 现场测量结果与有限元法一致，相差约5%。
To investigate the dynamic characteristics of a self-anchored suspension bridge (i.e. Tianjin Fumin Bridge), a real time kinematic-global navigation satellite system (RTK-GNSS) is used to achieve the displacement responses of the structure. Seeing the defect in the positioning accuracy of RTK-GNSS, a combined method (EEMDWP) of ensemble empirical mode decomposition (EEMD) and wavelet packet (WP) analysis is firstly put forward to improve the precision of the vibration signals. Subsequently, fast Fourier transform and the random decrement technique are applied to estimate the natural frequency and the corresponding damping ratio of the structure. Meanwhile, to contrast the field measurement results, the finite element model (FEM) of the structure is established. Finally, the analysis results indicate that: (1) the RTK-GNSS technique is a powerful tool for monitoring the deformation of long-span bridges; (2) the proposed EEMDWP method is demonstrated to be better than the single EEMD or WP method; (3) the structural dynamic parameters are successfully obtained (i.e. the first natural frequency: 0.5873 Hz, the corresponding damping ratio: 2.12%); (4) the results from the field measurement are in agreement with the FEM with a difference of about 5% from each other.