Optimization of Multiple Helical Fillets Surface to Suppress Rain-wind Vibration of Stay Cables: A Wind Tunnel Investigation

To develop a new cable surface for control rain wind induced cable vibration of stay cable. Stay cables are light and vulnerable structures. Therefore, it can be easily excited by wind or rain wind interaction. Stay cables wrapped with a single helical fillet have been proposed so far. However, these countermeasures could prevent cable vibration well, especially in dry conditions. Objective: Therefore, the objective of this research is to develop a new cable surface to control not only RWIV but also dry galloping of stay cable. A wind tunnel test will be used to investigate the RWIV characteristics and its new countermeasure. Results: First, a rain wind-induced vibration of circular stay cable was reproduced in a wind tunnel environment. The effect of upper and lower water rivulets was examined to understand their role on RWIV better. A rainfall simulator was employed to generate artificial rainfall for two different wind tunnel experiments. Finally, to control the RWIV of stay cables, novel multiple helical surface fillets were used. The upper and lower rain rivulets can play a significant role in energizing the RWIV. It was also found that the multiple helical surface fillets can suppress the cable vibration well both in wet and dry conditions. Multiple helical fillets cable surface could successfully prevent both the RWIV and dry galloping. To fabricate helical fillet cable to control cable vibration, 04 to 12 fillets with sizes ranging from 3mmx7.5mm to 5mmx7.5mm and a pitch of 2.95D-4.78D (D: cable diameter) are the most influential parameters and suggested herewith for practical application.