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、寿命延长和提高的安全性。结构健康监测可以及时准确地提供有关民用基础设施状态和剩余寿命的信息。它包括使用传感器对结构进行检测，并将收集到的数据转换为有意义的可操作信息，供结构的所有者或管理者使用，以便决策者可以采取明智和经济的维护和维修行动。该项目的重点是代表美国所有桥梁的60%的典型桥梁梁系统。 本项目的目标是研究创建和验证一个通用的健康评估系统，用于典型的梁桥，基于静态和动态测量应变，使用长规格光纤传感器。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来产生深远的社会影响。中性轴和变形形状是反映桥梁健康状况和使用性能的通用梁参数。这些参数的实时确定有可能使一个强大的桥梁健康监测评估方法。本项目中涉及的与确定这些参数相关的基本问题涉及：1）这些参数的可变性以及在受损和未受损条件下确定这些参数的不确定性，以及2）将收集的数据转换为对桥梁所有者或管理者有意义和可操作的信息。该项目的目标是建立一个可靠的方法，在确定中性轴的位置和变形形状的基础上，对桥梁中的梁进行性能和健康评估。最先进的长应变计光纤应变传感器在获取与全球结构规模相关的数据方面具有固有的优势。算法将基于一般概率方法，贝叶斯结构识别和性能预测模型来创建，并考虑到所收集数据的可变性和不确定性。实验验证将通过实验室测试和两座桥梁在使用中的控制测试进行。该方法将适用于现有的和新的梁桥，将不依赖于材料。

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.