Analysis Of Dynamic Characteristics Of H-type Single Tower Cable-stayed Bridge

In the field of bridge engineering,cable-stayed bridge has gradually become one of the main bridge types in contemporary construction due to the advantages of large spanning capacity,strong wind resistance stability,beautiful appearance and wide application range.The seismic performance of cable-stayed bridges is an important factor affecting the stability and safety of the bridge.Therefore,it is of great theoretical significance and engineering application prospect to analyze the dynamic characteristics of cable-stayed bridges.Taking the typical domestic H-type single-pylon cable-stayed bridge as the research object,this paper carries out research on the inherent vibration characteristic of the cable-stayed bridge,the seismic time-history response and the vehicle-bridge coupling vibration,which can provide a certain theoretical reference for improving the seismic resistance of the H-type single-pylon cable-stayed bridge.The main research contents of this paper are as follows:（1）According to the engineering design structural parameters of the H-type single-pylon cable-stayed bridge,the Ansys APDL program was used to establish the three-dimensional finite element model including the main tower,bridge pier,bridge deck,cable and other structures by defining element types,material properties,cross-sectional properties,and real constants,which lays the foundation for analyzing the natural vibration,seismic response and vehicle-bridge coupled vibration of the H-type single-pylon cable-stayed bridge.（2）The inherent vibration characteristics of the cable-stayed bridge under the action of gravity load and lane load were analyzed respectively.The first 10 natural frequencies and vibration modes of the cable-stayed bridge were calculated,and the influence of gravity load and lane load on the inherent vibration characteristics of the cable-stayed bridge was analyzed,which provides a reference for the subsequent dynamic response analysis and bridge engineering design.（3）The finite element model of the dynamic response of the H-type single-pylon cable-stayed bridge under the EL-Centro seismic load was established,and the modal superposition method was used to analyze the instantaneous response characteristics of the seismic load of the cable-stayed bridge.It selected the key positions,such as the cable-stayed bridge’s tower beam consolidation point,main beam midpoint,1/4-span midpoint of left span of main beam,main tower and right tower top,studied displacement response,acceleration response and response time history curve of stress of different nodes,and obtained the characteristic law of seismic response of the H-type single-pylon cable-stayed bridge,which provide a reference for the seismic design of the cable-stayed bridge.（4）The finite element model of the vehicle-bridge coupling vibration of the cable-stayed bridge was established.Considering the influence of driving speed,vehicle weight,and damping,the control variable method was adopted to analyze the displacement response and acceleration response characteristics of the cable-stayed bridge at different positions.Through above analysis,the vehicle-bridge coupled vibration response characteristics of the H-type single-pylon cable-stayed bridge were concluded,which provides a certain theoretical reference for the safe operation and later maintenance of the cable-stayed bridge.