Research On Parametric Vibration And Control Of Super-long Stay Cable Based On Finite Element Analysis

With the prosperity and strength of China’s construction,many large-span bridges that cross rivers and seas have been continuously built.Bridge types have emerged in an endless stream,including cable-stayed bridges,suspension bridges,viaducts,and composite system bridges.The main span of cable-stayed bridges has been increasing along with people’s traffic demand.Similarly,the length of stayed cables has also been increasing with the increase of the span,which is followed by further changes in stayed cables.The damping is further reduced,the vibration frequency is further reduced,and the modal frequency range of vibration is further enlarged,which can be closer to the vibration frequency of the entire cable-stayed bridge,increasing the possibility of parametric excitation of the cable,resulting in large-scale vibration of the cable.The huge vibration reduces the comfort of the traffic on the bridge deck.Cable-stayed bridges in actual engineering will be affected by various random load excitations,such as traffic load,wind load,seismic load,which will cause the vibration of the end of the stay cable.When the frequency and the stay cable’s own frequency meet the 1:1 multiple relationship,the stay cable will have primary resonance,and when the 2:1 multiple relationship is met,the primary parameter resonance will occur,resulting in large-scale nonlinear parameter vibration of the stay cable.In order to study the nonlinear parametric vibration characteristics of super-long stay cables and the control effect of viscous dampers on them,the paper takes Sutong Bridge and its stay cables as the research object,and mainly carries out the following four aspects:(1)Using ANSYS finite element software,the whole bridge finite element model and the cable finite element model of Sutong Bridge were established.The dynamic characteristics were analyzed,and the correctness of the model was verified.(2)Considering the factors of vehicle-bridge coupling and bridge deck irregularities,a vehicle-bridge coupling finite element model was established.Considering the speed limit requirements of Sutong Bridge,the possibility of large-scale parametric resonance of stay cables under vehicle load is analyzed.(3)Considering the randomness of the seismic load,the displacement response of the bridge under frequent,fortified,and rare earthquakes is numerically analyzed,and the displacement time history curve at both ends of the stay cable is extracted,and the cable end displacement excitation frequency of the stay cable is compared with that of the stay cable.Frequency matching is used to determine the stay cable that can have parametric resonance,and analyze the stay cable parametric vibration response of influencing factors such as external excitation amplitude,structural damping,and viscous dampers.(4)The bridge wind field was generated by the measured wind speed,and the bridge displacement response analysis under monsoon and typhoon was carried out.The displacement time history curve of the nodes at both ends of the stayed cable was extracted,and the stayed cable capable of parametric vibration was determined through frequency matching.The influence of external excitation amplitude,structural damping and external viscous dampers on the vibration response of stay cable parameters are analyzed.