Abstract:The structure and traffic load of the special-shaped steel single-pylon cable-stayed bridge in Xiping Avenue in Xining City of Qinghai Province are complicated. In order to ensure the seismic safety of the bridge and make the project able to implement smoothly, the analysis is carried out from three aspects of bridge spatial dynamic model modeling, friction pendulum bearing simulation and seismic motion input direction. The modeling calculation of bridge is completed. The result shows that when the seismic motion is input along the longitudinal bridge, the axial force and shear force of the side pylon are much greater than those of the main pylon. When the seismic motion is input along the transverse direction of the bridge, the axial force, shear force, and bending moment of the main pylon are greater than those of the side pylon. The friction pendulum vibration reduction and isolation bearing is selected, and its designed initial vibration reduction and isolation capacity is 10% of the vertical bearing capacity. Under the E2 strong earthquake, the bearing enters the vibration reduction and isolation swing working state, which effectively extends the natural vibration period of the structure and realizes the vibration reduction and isolation design of the bridge. The setting of expansion joints should reserve the sufficient beam displacement to avoid the collision between the beam and the abutment during earthquakes. A viscous damper is installed between the abutment and the main beam, which can effectively control the longitudinal displacement of the beam body and the bridge pylon, and play a role in reducing vibration and energy consumption.
