Dynamic Response Analysis Of Vehicle-bridge Coupling Under Damaged State Of Simply Supported Girder Bridge

The diseases of bridge will reduce the bearing capacity of Bridges and the service life of the bridge, which seriously affects the security and durability of the bridge. Therefore, it is very necessary for existing bridge in service to test and evaluate the bridge.Traditional load test is mainly in static load test, and as a general method also has many limitations, such as, closing traffic, test load cases out of operational status, etc. So, Method of detection and evaluation based on operating response is becoming more and more attention. Bridge health monitoring system that has been developed and implemented on long span bridge structures in recent years, provides rich operating response data. Therefore, evaluation method based on operating response is the urgent need for technology development of health monitoring.The thesis aims at T-beam simple supported bridges, which adopts the numerical simulation to simulate and analyze dynamic response of the bridge under different health status and preliminarily discuss the possibility of evaluation of bridge structures base on dynamic response. The main researches as follows:(1) First of all, the vehicle and bridge model is established by use of ANSYS, and second, the natural vibration characteristic analysis of model for healthy bridge, uses to preliminarily evaluate lateral connection and carrying capacity of model for healthy bridge.(2) First of all, through the MATLAB to calculate the different levels of road roughness. According to the document and result select road roughness of C as excitations of coupling vibration, which combines vehicle and bridge model to achieve the process of vehicle-bridge coupling vibration system. And second, dynamic characteristics analysis of model for healthy bridge is carried out based on vehicle-bridge coupling, which gains data of dynamic time-history to compare and analyze with damaged data. The last, according to the dynamic fragility analysis and actual projects, bearing damage and transverse connection damage is a common disease of T-beam simple supported bridges.(3) According to the related literature, the article decreases elasticity modulus of bearings and weld steel plates to achieve the simulations of damaged bearings and transverse. It uses the method of vehicle-bridge coupled vibration, considering random irregularity factor of bridge deck, to perform numerical simulation analysis for dynamic response characteristics of damaged simply supported girder bridge. Preliminarily discussing the change rule of vibration characteristics, impact effect, dynamic response characteristic on simply supported girder bridge under a special damage condition. The results can provide initial reference for the evaluation and damage identification on simply supported girder bridge.