Investagation On Vortex Induced Vibration Control Of Stay Cables In Cable-Stayed Bridges Based On Viscoelastic Dampers

As one of the most potential and competitve bridge forms today, cable-stayed bridge has the advantages of large-span, reasonable structure, aesthetic appearance and so on. With the increasing of the main span of cable-stayed bridge, the windinduced vibration problem of cables, as the prime load bearing part of cable-stayed bridges, is concerned by many experts and scholars at home and abroad. It is difficult to meet the requirement of all kinds of vibration controls of long span cables by traditional dampers and pneumatic measures of vibration reducetion. Based on the advantages of the viscoelastic material in the energy dissipation, the damped cross ties and the Mass Damper Tuned(TMD) measures of vibration reducetion are studied by wind tunnel tests that control the vortex induced vibration of stay cable models in this paper.The main research content and result are as follows:The mechanical properties tests of two kinds of viscoelastic dampers are performed to investigate change trends of the performance parameters with the loading shear displacement and frequency, and the wind-resistant fatigue property of dampers are studied. The results show that the performance parameters of two kinds of dampers present a decreasing trend with the increasing of shear displacement amplitude, while there are rarely affected by the loading frequency, and the windresistant fatigue property of dampers are not satisfied with the current standard.Based on the energy dissipation of the viscoelastic material, a cable-damper cross ties dissipation system is proposed and a wind tunnel experiment is carried out to investigate the influence law of controlling effect of the cable-damper cross ties system with different numbers and positions of cross ties. As is shown in the experimental results, the cable-damper cross ties dissipation system is quite efficient in reducing the vortex-induced vibration amplitude of cable and improving the critical wind speed of the vortex-induced vibration. The controlling effect of cable-damper cross ties system is better than cable cross ties system and it is 33-60.3%.An effective methods of reducing vortex-induced vibration by interspersing impact tuned mass damper devices on stay cable is put forward, and wind tunnel tests are carried out to verify the vibration control effect of the impact tuned mass damper devices using viscoelastic material. It is proved that the devices can reduce the vibration of cable effectively and the condition with the viscoelastic material as the impact material is significantly better than that with the steel.