Study On Seismic Isolation Of Low-pylon Cable-stayed Bridge

The low-pylon cable-stayed bridge,because of its novel structure and unique characteristics of the force,the number of built in recent years a gradual increase in the vibration,then the response has been paid attention to.Beginning,this paper introduces the destruction of bridge under the earthquake,and then tells the development situation of the extradosed cable-stayed bridge,the seismic design of bridges are described,finally,the bridge under earthquake action calculation theory,static analysis method,response spectrum method and dynamic time history analysis method are introduced to Ningjiang Songhua River Bridge,four tower ETA cable-stayed bridge as the engineering background,the full bridge model is established to carry on the analysis using the finite element software MIDAS / civil,the main contents are:(1)first come to the bridge's natural vibration period and vibration mode,and then use the reaction spectrum method respectively on the structure along the bridge,transverse and vertical vibration response is calculated,repeatedly to superimposed together were calculated the value of the maximum response structure under earthquake.(2)using history analysis method of structure along the bridge,transverse and vertical vibration response is calculated,and three to the acceleration is added to calculate obtained results and response spectrum method,the results were compared.(3)to study the structure of adding dampers under earthquake,the dynamic characteristics of the structure with damping compared with no damping data validation of dampers in the structure damping energy dissipation effect.Finally,the conclusions and suggestions are put forward,which provide the theoretical basis for the seismic design of the low tower cable-stayed bridge in the future.