Vehicle Information Recognition Based On Transverse Strain Of Box Girder Bridge Theoretical Research

In recent years,more and more bridges have collapsed due to vehicle overload.Therefore,the problem of bridge overload needs to be solved urgently.The vehicle information recognition method is one of the most intuitive and reliable technologies to solve bridge overload.However,the existing vehicle information recognition methods have limitations on the types and spans of bridges,especially for box girder bridges.In view of the above situation,combined with the characteristic that the transverse strain of the unit near the support of the box girder bridge is sensitive to the axle information,this paper proposes a vehicle information recognition theory based on the transverse strain of the box girder bridge.This theory is the process from the upper axle of the vehicle’s front axle to the lower axle of the rear axle,and vehicle information identification is carried out by collecting the lateral strain time history of the sensing unit near the support of the box girder bridge.First,this article theoretically analyzes the feasibility of the proposed vehicle information identification method;then,based on the engineering background of a highway bridge in Guangdong Province,the corresponding finite element model and laboratory scale model are established,which are verified by numerical simulation and model test The correctness of the vehicle information recognition theory proposed in this paper.Numerical simulation and model test results show that the method proposed in this paper can better identify the vehicle speed,wheelbase,total vehicle weight and axle load.The main research contents of this paper are as follows:(1)In view of the current situation of overloaded vehicles seriously damaging bridges,the research purpose and significance of this topic are proposed;the current research status of vehicle information identification methods at home and abroad is summarized,and the shortcomings of these methods are analyzed;the vehicle information proposed in this article is described in detail The basic principle of the identification method.(2)Carry out theoretical calculations on the vehicle information recognition method proposed in this paper.First,use the improved frame analysis method without lateral support to obtain the lateral mechanics calculation model of the box girder micro-element;second,use the moment distribution method in structural mechanics to calculate the bending moment calculation formula for the center of the bottom plate when the vehicle load acts on the center of the top plate of the box girder.;Immediately combine the relationship between bending moment and stress,stress and strain in material mechanics to obtain the calculation formula of the transverse strain of the box girder bottom plate;then through the influence line theory analysis,it is obtained that the vehicle enters the bridge end during the process of passing the box girder bridge.And the time history strain of the sensing unit near the bearing at the exit end;finally,the vehicle speed,wheelbase,total vehicle weight and axle load are calculated through the strain time history of the sensing unit.(3)The vehicle information identification method proposed in this paper is theoretically verified by finite element software and scale model test.Numerical simulation analyzes a total of seven working conditions to verify the feasibility and accuracy of the vehicle information identification method proposed in this paper;model tests simulates five working conditions to verify the applicability of the vehicle information identification method proposed in this paper.The verification experiment results show that the vehicle information identification method proposed in this paper can accurately identify vehicle speed,wheelbase,total weight and axle load.