Research On Vehicle-Bridge Coupling Vibration Of Prefabricated Segment Assembly Beam Bridge

With the development of economy,the traffic volume of the highway bridge is increasing,and the coupled vibration of vehicles and bridges is becoming more and more obvious.The prefabricated segment assembly structure has the advantages of high standardization and fast construction speed.It is applied to more and more bridges.However,its vehicle-bridge coupled vibration is rarely studied.In this paper,the vehiclebridge coupled vibration of prefabricated segment assembly beam bridge is studied.The main work and conclusions are as follows:(1)The triangular series superposition method is used to simulate the road roughness,and the one-half and one-quarter vehicle models are studied.According to the RungeKutta method,a program for solving a quarter vehicle model considering random road roughness is written in MATLAB.(2)The refined model of the bridge is established in ANSYS,and the epoxy joint is simulated by the constraint equation method.The control model is established to study the influence of large deformation effect and stress stiffening effect on the solution results in ANSYS,and the inter-system iteration method is used to solve the vehicle-bridge coupling model.The results show that the large deformation and stress stiffening effects have little influence on the solution results and can be ignored in the calculation.(3)Taking the vertical vibration response in the middle of each span and the stress at the measuring point of the cross-section as indicators,the effects of road roughness,vehicle speed and bridge damping on the vehicle bridge coupling vibration of prefabricated segment assembly beam bridges are studied.The results show that: The vehicle-bridge coupled vibration response of the prefabricated segment assembly beam bridge increases with the increase of road roughness,and decreases with the increase of the bridge damping ratio.The influence of vehicle speed on the vertical vibration in the middle of each span and the force on the shear key is not monotonous,and its influence will change with the change of vehicle position and measuring point position.The frequency of the vehicle-bridge force also has a non-negligible influence,and it is not monotonous.The influence of road roughness is the largest,and the influence of bridge damping is the smallest.The influence of the vehicle-bridge coupling vibration on the bridge structure is unfavorable.(4)It is found that under the single-vehicle load,the epoxy joints has little effect on vertical vibration response in the middle of each span.When the phase difference of the road roughness function is the same,the variation trend of vehicle bridge coupling vibration response caused by different road roughness is basically the same.The increase of mid span vertical vibration frequency is less than that of vehicle-bridge force excitation frequency.The influence of damping on bridge vibration is realized by changing the vibration characteristics of the bridge itself,rather than changing the vehicle-bridge force.The stress distribution in the cross section of the epoxy joint is uneven.When the vehicle passes through the section of the measuring point,the shear stress of the measuring point will change abruptly.(5)During the construction of the prefabricated segment assembly beam bridge,the road roughness should be controlled.For the research on the shear key stress of vehiclebridge coupling vibration,we should pay attention to the influence of fatigue stress.In the design process,the natural frequency,damping and other dynamic characteristics of the bridge can be designed to reduce the vehicle-bridge coupling vibration response.