Research On Vehicle-bridge Coupling Vibration Response Of Long-span Continuous Girder Bridge

During these years,with the prosperity of transportation,the amount of vehicles has augmented day by day,the load of vehicles has been continuously increased,and the driving speed has increased significantly.At the same time,the highway bridges are gradually becoming lighter,flexible,and large-span,which makes the problem of vehicle-bridge coupling vibration more prominent.When a vehicle is driving on a bridge,it will force the bridge to vibrate.It will cause fatigue and aging of the bridge,which will affect the service life of the bridge.Meanwhile,the vibration of the bridge will affect the vibration of the vehicle,resulting in a reduction in the safety and comfort of driving.Even when the excitation frequency of the vehicle is close to the natural frequency of the bridge,it will cause the vehicle and the bridge to resonate,resulting in aggravated bridge vibration and causing a bridge collapse accident.Therefore,the study of vehicle-bridge coupled vibration is of great significance to bridge structure design and operation management.This article relies on the Shanxi Province Science and Technology Research Project " the study of the dynamic characteristics of long-span continuous girder curved bridges based on sensitive elements"(No.201803D31076),based on a large-span continuous beam bridge,the bridge dynamic response under typical vehicle load is simulated and calculated.The main work and conclusions are as follows:(1)The dynamic equations of the two-axle vehicle plane model,the two-axle vehicle space model and the five-axle trailer space model are derived and established,and it lays a foundation for the analysis of vehicle-bridge coupling vibration.(2)The vehicle-bridge coupling vibration equation is established by the overall solution method.And by the means of modal synthesis method,the degree of freedom of this equation will be reduced.Because of the difference in the unevenness of the bridge surface corresponding to the left and right wheels,a spatial bridge surface unevenness model should be considered,and uses this method to solve vehicle-bridge coupled vibration equation.Comprehensively considering the respective advantages of bridge finite element software and MATLAB,a vehicle-bridge coupled vibration analysis program was compiled,and the reliability of the self-programmed program was verified.(3)Analyze sensitive parameters such as bridge surface unevenness,vehicle speed,vehicle load,suspension stiffness,and bridge damping ratio,research shows: when the unevenness of the bridge deck and the vehicle load increase,the dynamic response of the bridge increases greatly;when the stiffness of the vehicle suspension increases,the dynamic property of the bridge increases to a certain extent,but amplitude increment rate is relatively slight;when the bridge damping ratio increases,the bridge dynamic response shows a decreasing trend;there is no obvious regularity between vehicle speed and bridge dynamic response.(4)In order to carry out the safety assessment of the bridge operation phase,the related concepts of road service level and headway spacing were introduced,and the multi-vehicle-bridge coupling vibration analysis model was established,focusing on analyzing the effect of the bridge under different traffic flow states,research shows: as the traffic flow state deteriorates,the dynamic property of the key section of the bridge increases significantly,and its impact coefficient first decreases and then increases.By introducing and analyzing the distribution of vehicles under different traffic flow states,and it is found that reasonable distribution of vehicles can effectively weaken the superimposition effect of vehicles and reduce the vibration of bridge.Related research results can provide references for the design,construction and operation of long-span continuous beam bridges.