Wind-induced Cable Vibrations: Advancing in Comprehension of Excitation Mechanisms and Development of Countermeasures

风等环境因素引起的斜拉桥斜拉索振动是斜拉桥长期存在的问题。在过去的几十年里，这种结构的跨度越来越长，导致了更长的和更灵活的电缆。这一点，加上它们的低固有阻尼，使得电缆振动在近年来成为一个更严重的问题。尽管与不同类型的缆索振动相关的机制已经得到了更好的理解，并且已经提出并在实际桥梁上实施了各种控制方法，但在有无补充不同的振动抑制对策的情况下，仍然需要了解缆索行为的动力和空气动力学方面。****提议的研究计划侧重于推进电缆动力学和空气动力学方面的知识。短期目标是：a)研究各种实际因素对干斜索驰动机理的影响；B)评估长、柔性缆索特性和桥面运动对大跨度斜拉桥缆索网络性能的影响；C)研究交叉扎带和阻尼器组合混合系统在缆索振动控制中的潜在应用，并优化相关设计参数；d)对结构工程和风力工程领域的HQP进行适当的培训。本研究的长期目标是为开发新颖有效的抗斜拉索振动结构和气动对策奠定基础，为完善现有桥梁斜拉索设计准则奠定基础，并为桥梁结构和斜拉索无损健康监测方案和损伤检测方法的发展做出贡献。****所提议工作的空气动力学部分将进一步理解我们在流固相互作用方面的知识，并对风致电缆振动的相关机制有更深入的了解。在评估大跨度斜拉桥缆索振动控制方案的有效性时，对现有缆索网络分析模型的改进尤为重要。对不同构型的混合动力系统的动态响应进行分析研究，为理解这种被动振动控制对策的机理提供了良好的理论基础，并为确定决定其性能和设计的关键系统参数提供了依据。通过解决当今斜拉桥设计中一些最具挑战性但又最紧迫的问题，申请人非常有信心，这样一个领先的研究承诺的结果将为更可持续的民用基础设施的发展做出重大贡献

Vibrations of bridge stay cables due to environmental factors like wind is a long-standing issue in cable-stayed bridges. In the past few decades, the growing span length of this type of structure led to longer and more flexible cables. This, combined with their low inherent damping, renders cable vibrations a more serious problem in recent years. Though mechanisms associated with different types of cable vibrations have been understood better, and various controlling methods have been proposed and implemented on real bridges, much is still needed in appreciating the dynamic and aerodynamic aspects of cable behaviour with and without the supplementation of different vibration suppression countermeasures.****The proposed research program focuses on advancing knowledge in cable dynamics and aerodynamics. The short-term objectives are: a) to study the effects of various practical elements on the mechanisms of dry inclined cable galloping; b) to evaluate the impact of long, flexible cable feature and bridge deck motion on the performance of cable networks on long-span cable-stayed bridges; c) to investigate the potential application of using cross-tie and damper combined hybrid system to cable vibration control and optimize the associated design parameters; and d) to achieve proper training of HQP in the areas of structural engineering and wind engineering. As a long-term goal, the proposed research program aims at settling the base for developing novel and more effective structural and aerodynamic countermeasures to suppress stay cable vibrations, building a sound foundation for refining the existing bridge stay cable design guidelines, and contributing to the development of non-destructive health monitoring program and damage detection methods of bridge structures and stay cables.****The aerodynamic part of the proposed work will further comprehend our knowledge in fluid-structure interaction, and lead to a deeper insight of mechanisms associated with wind-induced cable vibrations. The refinement of existing cable network analytical model is particularly important when assessing the effectiveness of cable vibration control solutions on long-span cable-stayed bridges. The analytical study on the dynamic response of hybrid system with different configurations offers a sound theoretical base to appreciate the mechanics of this passive vibration control countermeasure and allows identifying key system parameters dictating its performance and thus design. By aiming at resolving some of the most challenging yet pressing issues in the design of cable-stayed bridges today, the applicant is very confident that the outcomes from such a leading-edge research commitment will contribute significantly to the development of more sustainable civil infrastructures.***