Mechanisms and mitigation of bridge stay cable vibrations

桥梁斜拉索由于风等环境因素引起的振动是斜拉桥中的一个当代问题。在过去的几十年里，这种结构的跨度不断增长，导致拉索变得更长、更灵活。这一点，再加上其固有的低阻尼，使得近年来电缆振动成为一个更加严重的问题。尽管与不同类型的拉索振动有关的机理已经有了更好的了解，各种控制方法也已经被提出并在实际桥梁上实施，但在有或没有补充不同的减振对策的情况下，仍然需要更多地评价拉索行为的动力学和空气动力学方面。 提出的研究计划旨在解决当今斜拉桥设计中一些最紧迫和最关键的问题。其目的是：a)建立基于概率的模型来预测外部阻尼式桥梁斜拉索的动力响应并评估其安全水平；b)研究缆索-桥面相互作用对外部阻尼器抑制斜拉索振动效果的影响；c)研究振动缆索与其周围流场之间的流固相互作用，以进一步阐明风致斜拉索振动的机理；以及d)在结构工程和风工程领域对HQP进行适当的培训。

Vibrations of bridge stay cables due to environmental factors like wind is a contemporary 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 aims at resolving some of the most urgent and critical issues in the cable-stayed bridge design today. The objectives are: a) to develop a probability-based model for predicting dynamic response and assessing safety level of an externally damped bridge stay cable; b) to study the impact of cable-deck interaction on the efficacy of external dampers in suppressing cable vibrations; c) to investigate the fluid-structure interaction between an oscillating cable and its surrounding flow field for further clarification of wind-induced cable vibration mechanisms; and d) to achieve proper training of HQP in the areas of structural engineering and wind engineering.