Study On Vehicle Bridge Coupling Vibration Response Of Curved Continuous Beam Bridge

In recent years,with the rapid development of highway construction,urban infrastructure and transportation systems,more and more curved bridges have been used in expressway crossriver connection,large urban interchange ramps and bridge head approaches.Compared with the straight beam bridge,the curvature factor of the curved girder bridge makes the bending and torsion coupling effect of the curved beam bridge,and the structural force analysis becomes more complicated.In this paper,a concrete curved continuous beam bridge on the ramp A of Changqing South Road in Xinyu City is taken as the research object,and a vehicle-curve beambridge coupled dynamic analysis model is established.A numerical method for the vibration analysis of the coupled model is proposed and a program for solving the motion equation is compiled.The impact factors of the bridge under single and multi-vehicle loads are analyzed,and the impact of the vehicle on the curved beam bridge impact during variable speed driving is also discussed.The main research work and conclusions of this study are as follows:(1)Based on ANSYS software,a three-dimensional vehicle model with 16 degrees of freedom and a spatial curve bridge model were used to establish a three-dimensional vehiclebridge coupled model and its vibration equation was derived.A solvable program for the system's vibration equation was independently developed through MATLAB platform,which effectively reduced the calculation time.Transient and dynamic load tests were used to verify the accuracy and applicability of the solver for vehicle-curved bridge coupled vibration response.(2)The influence parameters of vibration response of the curved girder bridge under vehicle load were analyzed,including vehicle speed,deck roughness,radius of curvature,vehicle eccentricity,damping ratio,the number of spans and support form.The results showed that vehicle speed,deck roughness,radius of curvature and damping ratio had great influence on vibration response.In addition,the impact effect between internal force and displacement of the curved girder bridge under vehicle load was very different.(3)The influences of parameters of the curved girder bridge on the vibration response of bridge under multiple vehicles were studied,including the influences of the number of vehicles loaded horizontally,the number of vehicles loaded longitudinally and the distance between longitudinal vehicles.The conclusions were as follows: the number of transverse loading vehicles had little influence on deflection and impact factor of internal force.Deflection impact factor of the main girder decreased with the increase of the number of vehicles loaded longitudinally,while the shear impact factor was reversed.However,as the longitudinal vehicle spacing increased,impact factor of the main girder deflection first increased and then decreased,while the deflection was opposite,indicating that the influence of the longitudinal vehicle spacing on the impact effect of the bridge could be ignored.(4)The influences of variable vehicle speed on the dynamic response of the bridge were studied,including two states of vehicle braking and acceleration.For vehicle braking,the influences of vehicle initial speed,braking position,braking force rising time and deck roughness were analyzed.The conclusions were as follows: compared with the results of the vehicle running at a constant speed,the impact effect of the bridge during vehicle braking was obviously larger.When vehicle was braking on the front half span of the bridge,impact factor of deflection and mid-span shear force was greater than that on the rear half span.The braking rising time and deck roughness had great influence on the dynamic impact effect.With the extension of rising time,deflection and impact factor of internal force gradually decreased,and the reduction also gradually decreased.For vehicle acceleration,the influences of vehicle acceleration position,initial velocity and acceleration on bridge vibration response were analyzed.The conclusions were as follows: for a given acceleration,when the acceleration position was further away from the fulcrum,deflection impact factor first increased and then decreased;when the acceleration position was greater than 1/4 span(25m),deflection impact factor was greater than the result under the condition of constant velocity.When acceleration increases gradually,deflection impact factor increased accordingly.When deflection impact factor increased to a certain value,it decreases but was larger than the result under the condition of constant velocity.However,impact factor of internal force not increased or decreased with the increase of acceleration,and the maximum moment impact factor of constant velocity was greater than that of different accelerations.