Cable-stayed Storm Vibration Analysis And Magnetorheological Damper Damping Applied Research

Stay cables of the long-span cable-stayed bridges are susceptible to vibration under wind loading, or wind incorporated rain excitation, or deck motion due to high flexibility, relatively small mass and very low inherent damping, such as vortex shedding, wake galloping, parameter resonance and wind-rain induced vibration. Large-amplitude vibration of cables may reduce the life of cables and threaten safe traffic, and has been considered today as one of the most critical problems for this type of bridge. Therefore, investigation of mechanism and countermeasures of cable vibration is very important for construction and maintenance of the cable-stayed bridges.Increasing the damping of cables is the most direct and efective way of suppressing cable vibration. Since the damping of long cables tends to be naturally very low, the addition of relatively small amounts of damping at or near cable ends can provide dramatic improvements in stability. Traditional approach to raise damping is installing passive damper between cable and deck, such as viscous (oil) dampers. The viscous dampers have been successfully used on a number of existed bridges in the world, however it is difficult to acquire optimal efect due to inherent disadvantages of this type dampers. In addition, the way to determine optimal parameter need to be improved and perfected. In the recent years, a new smart damper, magnetorheological (MR) damper, is developed for vibration control, which is made of smart MR fluid. MR damper has an excellent variable damping property and its damping force can be changed by adjusting voltage applied to damper. Therefore, semi-active control can be implemented with the damper.The dissertation retrospect the research of wind-rain induced vibration of cables and generalize its controlling means. Controlling means include the measure of aerodynamics and mechanical. Introducting magneto-rheological fluids and magneto-rheological (MR) Damper and the apply the system of cable-magneto-rheological (MR) Damper in Huanghe bridge which lies in Shandong BinZhou.The thes is applies the theory of Hamilton establishing the planar and place equation of the system of cable- magneto-rheological(MR) Damper. Calculating the reacting: of the longest cable in Huanghe bridge which attaching to the pulsating ivind loading.