Coupling Vibration Analysis Of Steel-concrete Composite Curved Continuous Girder Bridge And Vehicle

Due to the particularity of stress of steel-concrete composite curved bridge,under the driving load and other external loads,the stress and deformation are bending-torsion coupling,which causes the phenomenon of support creep and void.In order to understand the force mechanism of curved bridge under the action of vehicle and the causes of corresponding diseases,it is necessary to carry out fine analysis of vehicleaxle coupling.This thesis takes a steel-concrete composite curve continuous beam bridge as the research object.Based on ANSYS software and MATLAB,the parametric fast modeling auxiliary software for composite bridge is developed twice.By comparing and analyzing the calculation results with Midas beam element model,the software and the fine finite element model established by it have high accuracy and good applicability.Supported by this software,finite element steel-concrete composite bridge models with different curvature radius,number of diaphragms and boundary conditions are established,and the influence of the above parameters on the natural vibration characteristics of curved bridges is analyzed,which provides a numerical model basis for the subsequent refined analysis of steel-concrete composite curved bridge-vehicle coupling.Then,based on the basic principle of multi-body dynamics,the dynamic model of heavy-duty vehicle with 9 degrees of freedom on three axles is established.Combining tire-road contact theory model and unevenness theory,the above vehicle model and bridge model are established as vehicle-axle coupling dynamic model based on mode synthesis method,and PARK integration method is used to solve the dynamic response of curved bridge under vehicle action.Based on the basic principle of multi-body dynamics,the dynamic model of threeaxis 9-degree-of-freedom heavy-duty vehicle is established,and the above-mentioned vehicle model and bridge model are established as the dynamic model of the axle coupling based on the modal synthesis method based on the modal synthesis method to realize the solution of the dynamic response of the curved bridge under the action of the vehicle.Aiming at the problems of support creep and void caused by the position displacement of curved bridge,the radial,tangential and vertical reactions of the support of curved bridge under the vehicle-bridge coupling are studied,and the effects of vehicle speed,offset load and bridge surface irregularity on the response of support reactions are analyzed.The conclusions are as follows: when the vehicle is driving near the support,the radial and vertical reactions reach their peak values,while the vehicle is driving in the span,the tangential reactions reach their peak values.The peak value of radial reaction and tangential reaction is related to the second square of vehicle speed,and the vertical reaction of outer support increases with the increase of vehicle speed.The dynamic reactions of three kinds of supports increase with the increase of road surface roughness.The peak values of radial,tangential and vertical support reactions under grade C irregularity are 32.64%,6.28% and 18.2% higher than those under grade A irregularity respectively.Bias load has little effect on radial and tangential reactions,and the vertical reactions of supports on the side of bias load greatly increase.Aiming at the coupling effect of bending deformation and torsion deformation of curved bridge upper structure under the action of vehicle,the response of displacement and stress of curved bridge mid-span under the action of vehicle-bridge coupling is analyzed and studied.The conclusion is that both displacement and stress responses reach their peak values when the vehicle is in the mid-span and reach opposite peak values when the vehicle is in the adjacent span.Radial displacement is proportional to vehicle speed.Peak values of radial displacement at four speeds are 0.068 mm,0.088 mm,0.100 mm and 0.121 mm.Vehicle speed changes.Except radial displacement,the general trend of displacement and stress response curve remains basically unchanged.Peak values of response are not proportional to speed.Internal and external offset loads reverse the mid-span radial displacement to the offset side,while the overall trend of the remaining displacements and stress responses is essentially unaffected by the offset loads.With the improvement of irregularity level,the fluctuation amplitude of the response of the upper structure of the bridge increases.The above conclusions can provide reference for the design of this type of bridge.