| In the field of structural control, many efforts have been made in the research ofcontrolling flexible bridge structures. In this paper, Magneto-rheological(MR) fluiddampers were selected as control devices to control the vibration of large-spancable-stayed bridge under seismic excitations.Firstly, this paper gave an overview to the current development of structural vibrationcontrol theory and their application in bridge engineering.Secondly, in this paper, the theory and characteristic about magneto-rheological (MR)fluid are introduced. The work principle and calculating model of MR damper arepresented in the paper. Based on simplified model, namely Voigt model, the FEM model isset up.Thirdly this paper takes the north cable-stayed bridge of Runyang bridge as a researchobject, and applying ANSYS general FEM software to set up the FEM model of thiscable-stayed bridge structure. The special dynamical characteristics of this bridge areinvestigated, including the natural frequency, the features of natural models and so on.Tianjin wave, Taft wave and EI-Centro wave are chosen as the input ground motion, andtime-history analysis is adopted to acquire the structure's time-history curve of vibrationfeatures. The result show that the displacement, velocity and acceleration response of thestructure differs between the different ground motion records.Finally, this paper applies Magneto-rheological (MR) dampers to control the vibrationresponse of the cable-staged bridge under earthquake excitation, the model of which is setup based on Magneto-rheological (MR) dampers. The effect of Magneto-rheological (MR)dampers parameters (pressure and place where the MR dampers install) on controlling thecable-staged bridge structure response is analyzed. The results indicate that theMagneto-rheological (MR) dampers can diminish the displacement, velocity andacceleration response of the structure effectively, and attain the purpose of controllingstructure vibration response under the earthquake excitation. |
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