Innovative Hybrid Structural Systems and Smart Monitoring for Sustainable Bridge Infrastructure

提出的研究旨在开发创新设计和智能结构健康监测，以实现桥梁基础设施的可持续性能。主题1 -可持续混合桥梁系统的发展：申请人目前正在开发创新的无腐蚀混合系统。本研究的主要目的是开发一种可持续的、更持久的、更具成本效益的短跨和中跨桥梁系统的优化设计。该系统可应用于每年建成的数百座桥梁。在新系统中，上层建筑完全由抗腐蚀材料建造。该系统的优点包括减轻自重和增强耐用性。轻的重量减少了所需的预应力量和支架上的载荷，从而减小了下部结构的尺寸，或者允许更长的跨度，这可能导致多跨桥梁中支撑墩的数量减少，从而降低了初始成本。增强的耐久性降低了维护成本，并且可以使桥梁的使用寿命是传统桥梁的两倍甚至三倍。长期目标是为新桥系统的设计、制造和施工制定指导方针和程序。主题2 -结构健康监测损伤识别技术的发展：基于振动的损伤识别技术（DIT）正在发展中。它可以检测在役桥梁结构损伤，确定其位置，并估计其严重程度。DIT将离散小波变换和谱熵结合在一个相对的过程中，以检测和量化在环境振动下测量的桥梁动力响应中的损伤引起的干扰。这种基于相对小波熵（RWE）的DIT是一种实用的原位损伤识别手段，在这种情况下，桥梁的正常运行不能中断以进行动态激励试验，并且桥梁的参考（未损坏）状态的数据无法与当前（损坏）状态的数据进行比较。RWE DIT在静态和疲劳载荷下对各种桥梁构件进行了测试，初步结果证明了该技术在识别不同操作和环境条件下试验引起的损伤方面的有效性。本主题的目标是进一步发展DIT，以便能够描述各种类型的损害并量化其实际（而非估计）严重程度。这可以通过将有限元（FE）模型更新程序与开发的基于rwe的技术相结合来实现。为此，将从桥梁构件试验中获得的RWE指标与从有限元模型中获得的RWE指标进行比较。本研究将探讨不同的优化工具，以提高有限元模型的准确性。

The proposed research aims at developing innovative design and smart structural health monitoring for sustainable performance of bridge infrastructure. Focus is placed on two themes: Theme 1 - Development of Sustainable Hybrid Bridge Systems: Innovative corrosion-free hybrid systems are currently under development by the applicant. The main objective of this research is to develop an optimum design of a sustainable and more durable and cost-effective system for short- and medium-span bridges. The proposed system can apply to hundreds of bridges constructed every year. In the new system, the superstructure is built entirely from materials that are immune to corrosion. Advantages of the system include reduced self-weight and enhanced durability. The light weight reduces the required amount of prestressing and the load on the supports, resulting in a smaller size of the substructure, or allows for longer spans, which may lead to a smaller number of supporting piers in multi-span bridges and, hence, reduction in the initial cost. The enhanced durability reduces the maintenance cost and can lead to a bridge lifespan that is double or even triple that of the average traditionally constructed bridges. The long-term objective is to develop guidelines and procedures for the design, fabrication and construction of the new bridge system. Theme 2 - Development of Damage Identification Technique for Structural Health Monitoring: A vibration-based damage identification technique (DIT) is currently under development. It can detect structural damage, determine its location, and estimate its severity in in-service bridges. The DIT combines discrete wavelet transforms and spectral entropy in a relative procedure to detect and quantify damage-induced disturbances in bridge dynamic responses measured under ambient vibration. This relative wavelet entropy (RWE) based DIT is a practical means for damage identification in in-situ cases, where the bridge normal operation cannot be interrupted to perform dynamic excitation tests and when data from a reference (undamaged) state of the bridge are not available for comparison with data obtained from current (damaged) state. Preliminary results of implementing the RWE DIT in a variety of bridge components tested under static and fatigue loading have proved efficacy of the technique in identifying test-induced damage under varying operational and environmental conditions. The objective of this theme is to further develop the DIT to be able to characterize various types of damage and quantify their actual (not estimated) severity. This can be done by combining a finite element (FE) model updating procedure with the developed RWE-based technique. For this purpose, RWE indices obtained from bridge component tests will be compared with the ones obtained from the FE models. Different optimization tools will be investigated in this study to enhance accuracy of the FE models.