Vehicle-bridge Coupling Vibration Analysis And Comfort Evaluation Of Steel-concrete Composite Girder Bridge

Steel-concrete composite girder bridge is widely used because of their simple construction and full use of the advantages of steel and concrete.However,as the vehicle mass on the steel-concrete composite girder bridge is relatively large compared with the modal quality of the main beam,as the bridge span and vehicle load continue to increase,the bridge vibration will become more and more obvious.Vehicle-induced incentives not only affect the normal use and service life of bridge structures,but also affect the ride comfort and comfort of vehicles.Therefore,it is of great theoretical and practical significance to study the vehicle-bridge coupling vibration of steel-concrete composite girder bridge.This paper mainly conducts research from the following aspects:Firstly,based on the research results of domestic and foreign scholars on vehicle-bridge coupled vibration,this paper chooses to separate the vibration equations of the vehicle system and the bridge system by using the iterative method,and uses the Newmark-β method to solve the vehicle-bridge coupled system vibration equations.For the bridge type of steel-concrete composite girder bridge,the relevant theory of vehicle-bridge coupling vibration analysis is used,and the finite element model and nine-degree-of-freedom vehicle model of steel-concrete composite beam bridge are established using ANSYS software.The simulation program analyzes and obtains the dynamic responses of the bridge and the vehicle.Secondly,in view of the impact of bridge surface roughness on vehicle-bridge coupling vibration,combined with the Chinese standard GB/T7031-2005,using the trigonometric series method,the MATLAB software is used to compile programs to generate samples of bridge irregularities,and use this as the main excitation source.The effects of vehicle speed,vehicle weight,bridge surface roughness,vehicle suspension stiffness,vehicle tire stiffness and other factors on the dynamic response of bridges and vehicles were analyzed.Thirdly,with regard to the impact of heavy vehicles on the impact of steel-concrete composite girder bridge,this paper comparatively analyzes the impact of factors such as vehicle speed,vehicle weight,and bridge surface roughness on the displacement impact factor and bending moment impact factor,and compares the difference between the calculated impact factor and the standard value.Finally,on the basis of studying the vehicle-bridge coupling vibration law of the steel-concrete composite girder bridge,the pedestrian comfort and driving comfort under the influence of vertical vibration are evaluated.The analysis of the paper shows: Changes in vehicle speed,vehicle suspension stiffness,and vehicle tire stiffness have little effect on vehicle-bridge coupling vibration of steel-hybrid composite girder bridges.The increase in vehicle weight exacerbates the vibration effect of the vehicle-bridge coupling system of the steel-concrete composite girder bridge,which seriously endangers the safety of the bridge and must be given sufficient attention.When the bridge surface roughness grade is A,the impact factor is less than the specification value.When the bridge surface roughness grade is B,the impact factor is close to the specification value.When the bridge surface roughness grade is C,the impact factor is much larger than the specification value.The deterioration of the condition of the bridge surface will aggravate the vehicle-bridge coupling vibration effect of the steel-concrete composite girder bridge,resulting in a significant reduction in comfort,so the maintenance of the bridge surface pavement needs to be strengthened.