Health Monitoring of Multi-Strand Steel Tendons and Cable Stays for Civil Structures

项目负责人：Francesco Lanza di scaleco -PI: Frieder Seible University of California， San diego提案编号：0221707提案题目：土木结构多股钢筋和斜拉索的健康监测[项目摘要]现有建筑设施的结构健康监测正成为一个越来越重要的工程方面。结构健康监测包括确保适当的结构性能和早期发现关键损伤。本项目旨在开发一种广泛应用于索桥和预应力混凝土构件等土木结构的多钢丝钢绞线肌腱和斜拉索的健康监测方法。该方法的最终目的是1)实时测量所施加的载荷和2)检测关键损伤，包括腐蚀和断线。该项目将研究使用超声波应力波作为执行这些任务的潜在候选者。研究的中间目标包括：1)表征应力波在多线股中传播的色散行为（速度/频率关系）；2)完善了基于应力波传播速度监测的载荷测量方法；3)应力波对结构损伤的敏感性评估；4)开发一种方法来纠正温度对负载测量的影响。拟议活动的成功完成将有助于确保该国关键的民用基础设施组成部分，如桥梁的安全。该项目更广泛的影响将包括教育方面。研究生将直接参与所有的研究活动。一名本科生助理也将参与该项目。最近，结构健康监测和非破坏性评估的主题被纳入了加州大学圣地亚哥分校结构工程系的课程开发。目前正在编制关于这些题目的两门课程，一门在本科阶段，另一门在研究生阶段。研究活动的相关发现将被纳入这些课程的课堂讲座。在本课程的实验课程中，将会有超声波测量的演示。

PI: Francesco Lanza di ScaleaCo-PI: Frieder Seible University of California, San DiegoProposal number: 0221707Proposal title: Health Monitoring of Multi-Strand Steel Tendons and Cable Stays for Civil StructuresProject AbstractMonitoring the structural health of existing constructed facilities is becoming an increasingly relevant aspect of engineering. Structural health monitoring includes ensuring proper structural performance and providing early detection of critical damage. This project is aimed at developing a health monitoring method for multi-wire steel strand tendons and cable stays that are widely used in civil structures such as cable-supported bridges and prestressed concrete members. The ultimate purposes of the method are 1) real-time measurement of the applied loads and 2) detection of critical damage including corrosion and broken wires. The project will investigate the use of ultrasonic stress waves as potential candidates to perform these tasks.Intermediate objectives of the research include: 1) the characterization of the dispersive behavior (velocity/frequency relationship) of stress waves propagating in multi-wire strands; 2) the perfection of a method for load measurement based on monitoring the stress wave propagation velocities; 3) the assessment of the sensitivity of stress waves to structural damage in the strands; 4) the development of a method for correcting the effects of temperature on the measurement of load. Successful completion of the proposed activities will contribute to ensuring the safety of the Nation's critical civil infrastructure components, such as bridges. Broader impacts of the project will include educational aspects. A graduate student will be directly involved in all of the research activities. An undergraduate assistant will also collaborate to the project. The topics of structural health monitoring and non-destructive evaluation have been recently included in the curriculum development of UCSD's Structural Engineering department. Two courses on these topics are being developed, one at the undergraduate level and the other at the graduate level. Relevant findings resulting from the research activities will be incorporated into the classroom lectures for these courses. Demonstrations on ultrasonic measurements in strands will be given as part of the courses' programmed laboratory sessions.