Vehicle Load Identification Of Bridges Based On Monitoring Response

Vehicle load identification under operating conditions is important for developing vehicle load standards,fatigue analysis of bridge structures,bridge durability and safety assessment,and traffic planning management.Dynamic Weighing System(WIM)is widely used on some roads and bridges.However,the WIM system also has a high cost,complicated installation,and the need to excavate the foundation pit on the road surface.Around the 1980s,scholars proposed the "Bridge Dynamic Weighing System"(B-WIM).B-WIM identifies the vehicle load through the bridge by the response of the bridge structure under vehicle load.Compared with the traditional WIM,the B-WIM has a long weighing time,and the weighing accuracy is less affected by the dynamic load of the vehicle;the data acquisition instrument installation and maintenance does not interfere with the traffic and has no damage to the road surface;the collection system is simple and light,which is beneficial for reuse.However,it is generally believed that B-WIM is mainly suitable for small bridges.In this paper,the research on vehicle load identification based on different bridge types and monitoring systems is carried out.The main work is as follows:Firstly,for the small simple supported beam bridge,the vehicle load identification research is carried out,and the identification problems of vehicle speed,vehicle weight and axle weight are discussed.By establishing the finite element model of simply supported beam bridge,the biaxial vehicle model and the road roughness model The vehicle-bridge coupling system is composed,and the vehicle-bridge coupling numerical simulation analysis is carried out.Only the multi-point strain response of the simply supported beam bridge is used,and the axle component is used as the "scale" to invert the axle weight.Then,we explored how to apply B-WIM to larger span bridges.Taking the long-span arch bridge as an example,the feasibility and method of the application of B-WIM method on large bridges are studied.The correctness of the finite element structure model of arch bridge is verified by the static and dynamic load test.The vehicle is coupled and calculated by vehicle-bridge coupled dynamics.The axial stress response characteristics of the arch bridge boom under load are used to identify the vehicle load using BP neural network technology.Finally,based on the structural health monitoring system(HMS)implemented on most large bridges,the feasibility and method of combining B-WIM with HMS for large-scale bridge vehicle load identification are discussed.Based on the health monitoring system of the cable-stayed bridge,the practical theory and method of HMS-based B-WIM for large bridges are studied,and engineering application examples are given.The BP neural network method is used to construct the training samples of the network through the numerical simulation of the vehicle-bridge dynamic coupling analysis.The cable force and strain data are obtained by the cable-stayed bridge monitoring system.The monitoring data is analyzed and processed by wavelet decomposition and EDM technology.Identification of vehicle speed and vehicle weight.