Application of Structural Health Monitoring Techniques to Track Structural Changes in a Retrofitted Building Based on Ambient Vibration
Application of Structural Health Monitoring Techniques to Track Structural Changes in a Retrofitted Building Based on Ambient Vibration
复制标题
应用结构健康监测技术基于环境振动跟踪改造建筑的结构变化
DOI：
10.1061/(asce)0733-9399(2007)133:12(1311
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
A. Chassiakos
中科院分区：
文献类型：
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作者：
R. Nayeri;S. Masri;A. Chassiakos
复杂的问题之一，结构健康监测（SHM）方法的可靠性评估，预定在现场条件下实施的损伤检测与典型的基础设施系统，是缺乏实验测量，从这样的结构。特别缺乏的是物理结构的实验数据的可用性，在结构中进行量化的变化，而SHM研究正在进行。这正是本文的重点。由于1994年北岭地震，在大都市洛杉矶地区的一个关键的六层建筑物被发现需要显着的抗震措施。该建筑物装有14个最先进的强运动加速度计，这些加速度计放置在整个建筑物的不同位置和不同方向。仪器网络被用来定期获取广泛的环境振动数据集，涵盖了整个施工阶段，在此期间，建筑物从其原始状态演变到改造状态。本文评估的有用性的自然激励技术（NExT）结合特征系统实现算法（ERA），以确定其改造过程中的各个阶段的主体建筑物的模态特性的演变。此外，一个评估的影响，对系统的识别结果的重要用户可选择的参数，如：数据窗口的大小和重叠;参考自由度;和相关联的汉克尔矩阵的尺寸。尽管非常低的环境激励水平，和传感器的低空间分辨率，使用NExT/ERA算法产生了良好的识别结果的建筑物的主导模式。所识别的结构频率的变化与进行特定结构变化的时间相关。结果表明，这种独特的收集数据可以是非常有用的校准的准确性和灵敏度的各种SHM计划，以及在提供有用的识别参数的指导方针，可以帮助规划和部署的传感器网络和相关的数据收集计划的SHM应用程序。
One of the issues complicating the reliability assessment of structural health monitoring (SHM) methodologies slated for implementation under field conditions for damage detection in conjunction with typical infrastructure systems, is the paucity of experimental measurements from such structures. Particularly lacking is the availability of experimental data from physical structures, where quantifiable changes are made in the structure while SHM studies are being performed. That is precisely the focus of this paper. As a result of the 1994 Northridge Earthquake, a critical six-story building in the metropolitan Los Angeles region was found to need significant seismic mitigation measures. The building was instrumented with 14 state-of-the-art strong-motion accelerometers that were placed at various locations and in different orientations throughout the building. The instrumentation network was used to acquire extensive ambient vibration data sets at regular intervals that covered the whole construction phase, during which the building evolved from its original condition to the retrofitted status. This paper evaluates the usefulness of the natural excitation technique (NExT) in conjunction with the eigensystem realization algorithm (ERA) to determine the evolution of the modal properties of the subject building during the various phases of its retrofit process. Further, an assessment is made of the influence on the system identification results of significant user-selectable parameters such as: data window size and overlap; reference degree-of-freedom; and the dimensions of the associated Hankel matrix. In spite of the very low levels of ambient excitation, and the low spatial resolution of the sensors, use of the NExT/ERA algorithm yielded excellent identification results of the dominant modes of the building. Changes in the identified structural frequencies are correlated with the time that specific structural changes were made. It is shown that this unique collection of data can be extremely useful in calibrating the accuracy and sensitivity of various SHM schemes, as well as in providing useful identification parameter guidelines that can assist in the planning and deployment of sensor networks and associated data collection schemes for SHM applications.