Research On Vortex-Induced Vibration Of Long Span Bridge And Aerodynamic Restriction Measure

With the application of new materials as well as development of design and construction technique, modern bridges are becoming longer and longer. Bridge tends to long span, slender girder, light, flexible and small damping. Bridges are sensitive to the action of wind and their dynamic response are distinct. Aeroelastic problems often restrict the design of structure strength, rigidity and stability. Wind-induced vibration (aeroelastic effect) of long span bridges has become the vital problem in the fields of bridge engineering and wind engineering. Vortex-induced vibration is easy to excited when long span bridges under low speed wind. Although vortex-induced vibration is a kind of limited amplitude response, it occurs at low wind speed with relative large amplitude, which will affect the strength and fatigue of the structure and comfort of users. Therefore, it is significant to study the vortex-induced vibration of long span bridge.Based on Xihoumen bridge, This thesis investigate it's vortex-induced vibration by wind tunnel test. The wind tunnel test was carried out in the uniform wind field, and response of the bridge for wind action was measured for the completed stage and 100% erection stage at different attack angles. Vortex-induced response of girder deck varing with wind speed, attack angles and damping levels are obtained by comparing and analyzing the test results. Also the test results indicate the influence of vortex-induced vibration with the number of Re. At last, this thesis researches the aerodynamic means on mitigation of vortex-induced vibration by using half deflector and full deflector. And it can be reference of wind design for the same kind of bridges.