Condition Monitoring of Concrete Structures

由于各种影响，加拿大老化的基础设施正在出现恶化和损坏的迹象。2016年加拿大基础设施报告卡（CIRC）得出结论：“在目前的实践（投资、运营、维护）下，大多数基础设施，即使今天处于良好或非常良好的状态，随着它们的老化，将需要越来越大的投资。”以桥梁为例，中国保监会观察到，桥梁的实际平均年再投资率为0.8%，而资产管理从业者通常将桥梁的再投资率目标设定在1.0%至1.7%之间。这种实际投资的赤字将不可避免地导致优先维护项目。对于任何涉及结构问题的决策，都需要利用先进的传感和计算技术来评估累积损伤的有效方法。如果没有适当的先进工程工具，对基础设施状态的评估将是昂贵的，而且容易出错。结构健康监测已成为保障基础设施安全的重要组成部分。SHM的目标可以概括为：(i)结构性能的成本效益评估，（ii）损伤的检测和定位，以及（iii）结构健康预测。SHM的一个重要组成部分是系统识别，其重点是通过响应测量建立有效可靠的结构模型。结构系统识别需要收集现有结构的数据，如位移、加速度和应变。

Canadian aged infrastructures are showing signs of deterioration and damage due to various effects. The 2016 Canadian Infrastructure Report Card (CIRC) concluded that: “under current practices (investment, operations, maintenance), the majority of the infrastructures, even if in good to very good condition today, will require increasingly larger investments as they age.” In the particular case for bridges, the CIRC observed that the actual average annual reinvestment rate of bridges is 0.8%, whereas asset management practitioners typically target a reinvestment rate for bridges in the range of 1.0% to 1.7%. This deficit of the actual investment will lead inevitably to prioritizing maintenance projects. For any decision making concerning structural problems, effective approaches are needed for assessing the accumulated damage using advanced sensing and computational technologies. Without the proper advanced engineering tools, the evaluation of the state of infrastructures can be costly and prone to error. Structural Health Monitoring (SHM) has become a major component to ensure the safety of infrastructures. The goals of SHM can be outlined as: (i) cost effective assessment of structural performance, (ii) detection and localization of damage, and (iii) structural health prognosis. An important component of the SHM is system identification, which focuses on developing an effective and reliable model of the structure through response measurements. Structural system identification requires collecting data from existing structures such as displacement, acceleration and strains. Until very recently, the most common monitoring of infrastructures was carried out using visual examination by trained engineers. With the development of technologies, various other methods have been introduced in the realm of SHM. Nondestructive monitoring techniques used previously included acoustics, thermography, Xrays, images processing and many others which required direct access to all the parts of the structure. This condition is not possible to achieve in case of complex structures. The present proposal attempts to integrate novel technologies including image processing to study specific SHM related problems in structures. The research program focuses on advancing knowledge on SHM applications in accessing the structural integrity of infrastructures. The short term objectives are: (i) to develop a methodology for evaluating damage in existing concrete structures including computer vision-based technology, (ii) to establish a diagnostic tool to evaluate the extension of induced damage in concrete structures, and (iii) to train Highly Qualified Personal (HQP) on the usage of modern technologies in SHM. The long term objective of the research proposal aims at settling the base for developing an integrated tool for SHM.