Ambient vibration re-testing and operational modal analysis of the Humber Bridge
Ambient vibration re-testing and operational modal analysis of the Humber Bridge
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DOI：
10.1016/j.engstruct.2010.02.034
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发表时间：
2010-08-01
影响因子：
5.5
通讯作者：
Cunha, Alvaro
中科院分区：
文献类型：
--
作者：
Brownjohn, J. M. W.;Magalhaes, Filipe;Cunha, Alvaro
2008年7月，由英国、葡萄牙和香港组成的联合小组对亨伯大桥进行了环境振动调查。这项工作有几个目的，其中包括评价目前的仪器和系统识别技术，以及生成模态特性的实验数据集，用于验证和更新情景模拟和结构健康监测的有限元模型。这次演习是一个项目的一部分，该项目旨在为三座具有里程碑意义的欧洲悬索桥开发在线诊断能力。十个独立的三轴加速度记录仪被部署在所有三个跨度沿着和所有四个桥塔的位置，连续五天进行一小时的记录。将来自记录仪的时间序列片段进行合并，并使用几种操作模态分析技术来分析这些数据，并组装代表桥梁所有结构部件在所有三个维度上的整体行为的模态模型。本文描述了用于练习的设备和程序，操作模态分析（OMA）技术用于系统识别，并提出了完整结构的关键振动模式的模态参数。技术，自然激励技术/特征系统实现算法，随机子空间识别和多最小二乘频域方法，进行了比较，并与1985年的桥梁测试，在可以直接比较的情况下，23年来几乎没有显著的模态参数变化。目前的测试表明，由于与先前的测试相比，时间表缩短，因此具有明显的优势。即便如此，参数估计值在不同方法和同一方法的变体之间表现出显著的变异性，同时也随时间变化并具有固有的变异性。(C)2010爱思唯尔有限公司版权所有。
An ambient vibration survey of the Humber Bridge was carried out in July 2008 by a combined team from the UK, Portugal and Hong Kong. The exercise had several purposes that included the evaluation of the current technology for instrumentation and system identification and the generation of an experimental dataset of modal properties to be used for validation and updating of finite element models for scenario simulation and structural health monitoring. The exercise was conducted as part of a project aimed at developing online diagnosis capabilities for three landmark European suspension bridges.Ten stand-alone tri-axial acceleration recorders were deployed at locations along all three spans and in all four pylons during five days of consecutive one-hour recordings. Time series segments from the recorders were merged, and several operational modal analysis techniques were used to analyse these data and assemble modal models representing the global behaviour of the bridge in all three dimensions for all components of the structure.The paper describes the equipment and procedures used for the exercise, compares the operational modal analysis (OMA) technology used for system identification and presents modal parameters for key vibration modes of the complete structure.The results obtained using three techniques, natural excitation technique/eigensystem realisation algorithm, stochastic subspace identification and poly-Least Squares Frequency Domain method, are compared among themselves and with those obtained from a 1985 test of the bridge, showing few significant modal parameter changes over 23 years in cases where direct comparison is possible.The measurement system and the much more sophisticated OMA technology used in the present test show clear advantages necessary due to the compressed timescales compared to the earlier exercise. Even so, the parameter estimates exhibit significant variability between different methods and variations of the same method, while also varying in time and having inherent variability. (C) 2010 Elsevier Ltd. All rights reserved.