Influence of Wind Load on Vehicle-bridge Coupling Vibration and Riding Comfort
In order to ensure the safety of the long-span bridge structure,and the stability and comfort of vehicle running on bridge,a coupling vibration analysis model for wind-vehicle-bridge is established.The roughness of the bridge surface with different grades is simulated by using the trigonometric series method to study the excitation source of the vehicle.The vertical and lateral wind load is generated by using the fast spectral analysis method.A dual-axle,four-wheel,13-degree-freedom car model is established.The Jiujiang Yangtze River bridge with a span of(180+216+180)m is selected as the engineering background.A finite element model for the bridge is established for natural frequency and vibration mode calculation.The mode superposition method is used to establish the differential equations of vehicle-bridge coupled vibration balance,and Newmark-β integral iteration is adopted to solve the time varying equations.The specification ISO2631-1997 is used to calculate the vibration response of the vehicle body,and the total weighted acceleration root-mean-square of vehicle is calculated.The acceleration time history is performed with spectrum analysis to evaluate the driving comfort.The dynamic responses and riding comfort are analyzed when vehicles passing the bridge under different wind loads,driving speeds and bridge roughness,and the dynamic loads of wind and vehicles on the bridge are calculated as well.The result shows that the dynamic responses of the vehicles increase with the increase of wind speed,the deterioration of bridge surface roughness and the raise of vehicle speed.The riding comfort will deteriorate accordingly.The increase of the wind velocity reduces the maximum vertical displacements of the bridge,while the vertical acceleration and lateral vibrations increase significantly.Long-span bridges are sensitive to wind and vehicle dynamic loading,therefore,sufficient attention should be paid on the design and operation stages of bridges to ensure the safety of both bridge structure and running vehicles.
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