Stayed Cable Vibration And Damping Measures For Extra-large Span Cable Stay Bridge

Cable-stayed bridge is widely used in modern transportation projects. With rapid development of design concept, calculation method, material technology and constant improvement of construction method and equipment, main span of cable-stayed bridges is becoming larger and larger and the length of stayed cable is becoming longer and longer. The longest cable for Sutong Bridge reaches 577m. Stayed cable is very vulnerable to vibration as it is with low rigidity, low damping ratio and light weight. Cable vibration mainly consists of two types, i.e. wind-induced vibration due to instability of aerodynamic effect and stress-related vibration induced by structural interaction. Vibration induced by wind and rain has always been the focus for bridge engineering and wind engineering researchers both home and abroad in the past decade.This paper deals with analysis of possible cable vibration types and static and dynamic characteristics of the cable, carries out preliminary analysis of vibration mechanism for stress-related vibration, linear internal resonance and wind and rain induced vibration, investigates possible mitigation measures and put forward design principle and design method for cable mitigation in systematic and all-round manner. Based on relevant test, research and investigation carried out for Sutong Bridge project, this paper addresses structural property and specific mitigation measures for cables used on this bridge, which is very helpful for Sutong Bridge construction and will also benefit similar projects on cable vibration control, design and construction.