Research On Vibration Control Of Stay Cable Based On Viscous Shear Damper

Vibration control technology for stayed cables is relatively mature.Vibration reduction through cables with external dampers and built-in rubber rings has become an important part of the construction of cable-stayed bridges.With the development and application of ultra-long cable and the improvement of technical requirements,new problems and new research ideas have been added to the vibration control of cables.This paper is a study of the Feiyunjiang long-span cable-stayed bridge and its cables.The object of this paper is to study the influence of the cable vibration control from the aspects of the cable relaxation of the cable-damper system and the changes in the additional stiffness of the damper and the damper clearance caused by the deterioration of the damper,including the wind-induced vibration of the cable Research and analysis of two types of vibration of parametric vibration of cables and cables.The main tasks are as follows:(1)The research results of cable vibration and its control at home and abroad are reviewed,and some recent cable vibration problems,new vibration damping methods and new vibration dampers are reviewed.Expounded the research significance of new cable vibration reduction technology.(2)A free vibration mechanical model of the cable is established,and the free vibration curve equation of the cable is derived.The natural frequency characteristics of the cable with and without lateral stiffness are analyzed.The mechanical model of vibration damping under the action of the cable static force is deduced,and the expression of the coupled mode damping ratio is obtained.The distribution of the mode damping ratio of the cable is solved by Matlab programming.Relationship curve between damping ratios.The calculation of the damping ratio by the higher-order measurement of the actual measured cable proves the correctness of the relationship of the mode damping ratio,and the low-order damping ratio of the actual cable is deduced,which has great engineering application value.(3)After understanding the vibration and damping characteristics of the cable,the constitutive change and relaxation rate of the cable after relaxation were experimentally studied.Relaxation experiments were performed on zinc-aluminum alloy steel wires and steel strands,and the corresponding relaxation rate change test data was obtained.The constitutive relationship of the relaxation rate changes with time was fitted by linear regression values.Based on the obtained constitutive relationship,the fundamental frequency changes of steel strands after decades of use are derived,which has a lot of help in the measurement and evaluation of cable performance and cable practical life.(4)Based on the Davenport wind speed spectrum,the pulsating wind at the actual simulation point of the cable was simulated,and the time history of the pulsating wind speed at the simulation point was obtained,and the pulsating wind load of the cable was converted.Through the cable element building function in sap2000,the cable model was simulated by using multi-section transfer frame elements,and the obtained wind load was input to obtain the cable model under wind load.A comparative study and analysis of the displacement amplitude of the wind-induced vibration span of the cable and the corresponding energy dissipation curve of the damper due to the additional stiffness changes and damper clearance changes after the damper degradation.The results show that the additional stiffness of the degraded damper has a small effect on the wind-induced vibration of the cable,but the change in the clearance has a significant adverse effect on the cable-damper system.(5)The mechanical model of cable vibration damping is deduced,and the actual cable parameter vibration characteristics and beat phenomenon are analyzed by RungeKutta iterative numerical method using MATLAB programming.The cable parameter vibrates the axial excitation frequency.The influence of the change of the damper clearance on the vibration of the cable is studied through comparative analysis.(6)In order to solve the influence of the deterioration of the traditional damper on the vibration control of the cable,a shear-type viscous damper is designed,and the basic mechanical properties,fatigue performance and minimal deformation of the damper are verified by experimental and theoretical methods Small gap)energy consumption and other performance indicators.Finally,the measured damping ratio of the actual cable with the damper verified the good damping capacity and small deformation energy consumption of the damper.Provides a more comprehensive damper for vibration reduction projects.