Study On Wind-induced Vibration And Coupled Vibration Of Vehicle And Cable-Stayed Bridges

In recent years, there are more and more cable-stayed bridges in construction. So as two main vibration styles, the rain-wind-induced vibration of stayed-cables and coupled vibration of vehicle and cable-stayed bridge have been dominant concern in engineering. This two aspects are deeply researched in this paper, the main contents includes following aspects.1. The styles of wind-induced vibration of cables are discussed. The research methods and recent progress are introduced. The various vibration reduction methods of rain-wind-induced vibration are introduced. And the features and progress of coupled vibration of vehicle and cable-stayed bridge are introdu- ced too.2. Three-dimension model for rain-wind-induced vibration of stay cable is established. The lag of stay cable is considered. The motion of rivulet is supposed to be harmonic. Its frequency is equal to the first modal frequency of stay cable. The in-plane and out-of-plane displacement response at the 1/2 length and 3/4 length from the top of stay cable, and their amplitude- frequency curves are obtained. The results show that the vibration of stay cable is mainly single-mode vibration. In-plane vibration is the chief danger to the safety of stay cable. The influences of wind velocity and air density on the amplitude of displacement response are investigated. The results show that the amplitude firstly increases, afterwards decreases along with increase in wind velocity. And the amplitude increases with increasing air density. Two MR dampers are applied for vibration mitigation. A segment of displacement response when it achieves stationarity is obtained. In order to optimize the effect of vibration mitigation, the relation between modal damping ratio and voltages and the location of the dampers is investigated. It's shown that the modal damping ratio has an optimization voltage, and the effect of vibration mitigation will be better when the location of dampers is a bit higher.3. The dynamic response of coupling vibration system of cable-stayed bridge and vehicle is investigated, and the road roughness and wind load is considered. The nonlinear dynamic model is conducted. The whole process of vehicle crossing bridge is simulated. The responses of bridge deck and vehicle are gained, and the relation among the responses and road roughness, wind load, vehicle velocity is received. The results show that the response of middle of the bridge and vehicle are increasing with the increase of road roughness. The road roughness is the main factor to the response of bridge and vehicle. The response of the middle of cable is increasing with the increase of winds velocity. The change of vehicle velocity has small influence on the response. So the vehicle velocity is not the main factor.4. According to the three-dimension model for rain-wind-induced vibration of stay cable which is established, the two DOFs coupling nonlinear dynamics equations are researched without considering the second vibration modal and the damper. The phase portraits and Poincare sections are gained when the amplitude of the rivuletηm is in different values. The bifurcation curves are got by choosingηm as the bifurcation parameters. The abundant nonlinear dynamical behavior is displayed.