Moving Load Identification And Experimental Study Of Bridge Based On Measured Dynamic Strain

With the continuous improvement of the speed of the car,the increasing traffic density,the load gradually increased,the bridge safety accidents caused by vehicle load are often occurred.Moving load identification belongs to the typical second inverse problem of vibration,that is,known system and response to excitation.It is not only an effective way to establish the vehicle load model,improve and develop the bridge health monitoring system,but also the main basis for the design department to carry out the bridge design checking and the traffic management department to carry on the traffic regulation,bridge(or other infrastructure)management,health safety assessment and management measures,that has important research and application value.In this paper,the moving strain identification method based on the measured dynamic strain is used to identify only a single vehicle or a very sparse vehicle.Without considering the lateral distribution of the load,the dynamic strain line measurement method,multi-vehicle lateral position,Research on Speed,Shaft Number,Wheelbase and Shaft Weight Recognition Technology.The main work and conclusions of the paper include:1.The multi-rigid-body dynamics model and the finite element model of the bridge subsystem are established.According to the idea of separate modeling and local coupling,the vibration analysis model of axle system is established based on the vertical coupling relation,and the system motion equation is deduced.The algorithm of Matlab calculation is used to solve the dynamic analysis model of the axle system,and the dynamic response of the bridge is calculated based on the iteration results.The numerical results show that the response of the vehicle-bridge coupling vibration is solved under the whole process iteration method,which can improve the efficiency of calculation and reduce the memory consumption.It is helpful to simulate the behavior of bridge and bridge on each axle.2.This paper proposes an improved method of multi-vehicle moving load identification based on measured dynamic strain,and deduces the multi-vehicle moving load identification algorithm from the aspects of bridge strain influence line measurement,axle information identification and vehicle axle identification.The analytical model was validated.The results show that the axle information and vehicle gross weight recognition error is below 9.4%.3.The method of identifying the axle information based on the wavelet transform method is established by extracting the wavelet high frequency coefficient curve under the specific scale of the dynamic response time response and the local maximum value method to identify the peak corresponding to the axle information.The results of numerical and experimental results show that the axle information can be identified by extracting the wavelet high frequency coefficients of the specific scale,which can reduce the influence of the interfering signal and can identify the axle information with the problem of not obvious peak and false peak.4.Based on the load test data,the four vehicles were divided into four groups at7.5km / h,9.5km / h,13.7km / h and 20.8km / h respectively.According to the measured data,the axle information identification is carried out.The vehicle speed identification error is less than 5.11% and the wheelbase identification error is less than14.4%.