The Research On The Application Of MR Damper In Cable Vibration Mitigation

In recent years, the span of modern cable-stayed bridge has become longer (the longest span of cable-stayed bridge has been over 1000 meters in the world, and it will develop longer in the future), Generally, with the span gets more longer, the frequency of the bridge is more lower. So the cable-stayed bridge will be sensitive to external-induced vibration, Which induced stay cable to vibrate more easily.Large-amplitude vibration of cable may reduce the life of cable and threat the safety of bridge, and has been considered as one of the most critical problems for this type of bridge. Therefore, investigation into the mechanism of cable vibration and cable vibration mitigation measures is very important for construction and maintenance of the cable-stayed bridge.This thesis takes the Hunan Yueyang Dongting Lake Bridge,Changsha Hongshan Bridge and Changsha Liuyang River Bridge as the project background, supported by the National Natural Science Foundation project"Field measurements of Rain-Wind-Induced cable vibration on the Yueyang Dongting Lake Bridge in Hunan province", carries out some researches as follow:1. This thesis introduces the development of cable-stayed bridge,the necessity to study the cable vibration, briefly introduces the mechanism of cable vibration and cable vibration mitigation measures.2. This thesis carries on the widespread investigation into the mechanism of cable vibration and cable vibration mitigation measures, then analyses them in detail.3. This thesis presents the rheological property of magnetorheological fluid(MRF),the principle of work and design of magnetorheological fluid damper (MRFD), studies the mechanical performance of RD-1005 MRFD and permanent magnetism adjustable assemblage MRFD, finally gives a comprehensive description of mechanical models of MRD.4. This thesis introduces the application of RD-1005 MRFD in Hunan Yueyang Dongting Lake Bridge and permanent magnetism adjustable assemblage MRFD in Changsha Hongshan Bridge and Changsha Liuyang River Bridge. The studies on cable vibration mitigation field tests in these bridges are presented.5. The wavelet analysis technique is applied in this thesis to identify the modal parameters of cable from in-site cable vibration mitigation test data.