Fiber Optic Method for Bridge Health Assessment Based on Long-Gauge Sensors

对于民用基础设施，需要进行结构健康监测，以提供优化的维护、延长使用寿命和提高安全性。结构健康监测可以提供关于民用基础设施状况和剩余寿命的准确和及时的信息。它包括用传感器对结构进行仪器测量，并将收集的数据转换为对结构所有者或管理人员有意义和可操作的信息，以便决策者能够采取知情和经济的维护和维修行动。该项目侧重于典型的桥梁梁系统，这些系统占美国所有桥梁的60%。本项目的目标是研究建立和验证基于使用长径光纤传感器的静态和动态测量应变的典型梁式桥的通用健康评估系统。这项研究将提供避免破坏性关闭和灾难性故障的方法，同时还确保持续可靠的健康评估。该项目的成功将通过解决公共安全问题和最大限度地减少经济干扰而产生深远的社会影响。中性轴和变形形状是反映桥梁健康和使用状况的通用梁参数。这些参数的实时确定有可能实现稳健的桥梁健康监测评估方法。与本项目中涉及的这些参数的确定相关的基本问题涉及：1)这些参数的可变性以及在损坏和未损坏的条件下确定这些参数的不确定性，以及2)将收集的数据转换成对桥梁所有者或管理者有意义和可操作的信息。该项目的目标是创建一种可靠的方法，基于确定中性轴的位置和变形形状来评估桥梁中梁的性能和健康状况。最先进的长规光纤应变传感器在获取与全球结构尺度相关的数据方面具有固有的优势。算法将基于一般的概率方法、贝叶斯结构识别和性能预测模型来创建，并考虑到收集的数据中的可变性和不确定性。实验验证将通过实验室测试和在使用中的两座桥梁的控制测试进行。该方法适用于既有和新建的梁桥，不依赖于材料。

For civil infrastructure there is a need for structural health monitoring to provide an optimized maintenance, lifetime extension, and improved safety. Structural health monitoring can provide accurate and in-time information concerning condition and residual life of civil infrastructure. It consists of instrumentation of the structure with sensors and transformation of the collected data into meaningful and actionable information for the owner or manager of the structure, so decision makers can undertake informed and economical maintenance and repair actions. This project focuses on the typical bridge beam systems that represent 60 percent of all US bridges. The objective of this project is to pursue research in creating and validating a universal health assessment system for typical beam bridges based on static and dynamic measured strains using long-gauge fiber optic sensors. This research will provide means to avoid disruptive closures and catastrophic failures, while also ensuring on-going reliable health assessment. The success of the project stands to have profound societal impact by addressing public safety and minimizing economic disruption. The neutral axis and the deformed shape are universal beam parameters that reflect bridge health and performance condition. Real-time determination of these parameters has potential to enable a robust bridge health monitoring assessment method. Fundamental questions associated with determination of these parameters addressed in this project are related to: 1) variability of these parameters and uncertainty in their determination under damaged and undamaged conditions, and 2) transformation of the collected data into meaningful and actionable information to the bridge owner or manager. The objective of the project is to create a reliable method for performance and health assessment of beams in bridges based on determination of the position of the neutral axis and on deformed shape. State-of-the-art long-gauge fiber optic strain sensors have inherent advantage to acquire data relevant to the global structural scale. Algorithms will be created based on general probabilistic approaches, Bayesian structural identification, and performance prediction models taking in to account variability and uncertainties in collected data. Experimental validation will be performed both through laboratory tests and controlled tests on two bridges in-use. The method will be applicable to existing and new beam bridges and will not be material dependent.