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

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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.***