Study On Vehicular Impact Coefficient Of Straight Girder Bridge

With the development of global economy, the pressure caused by transportation industry is very great. how to guarantee the safety of bridges and propose the reasonable scientific impact coefficient under the premise of guarantee the economic rationality of investment, is an important issues of bridge structure research. The thesis proposes the reasonable Vehicle-bridge coupling calculation model and develops the solving algorithm. The model is the premise of researching bridge in mobile system response under load, and is the basis of further analysis of the impact of the bridge under live load factor.Firstly, the thesis introduces the development of impact coefficient under the moving load and the criteria of many other countries at present, secondly, three models for vehicle-bridge coupled vibrations, namely moving spring mass system, two-degree of freedom vehicle model, four-degree of freedom vehicle model and five-degree of freedom vehicle model were derived according to vibration theory and the hypothesis of Euler-Bernulli beam。Through using modal analysis method, thepartial differential function was changed to differential function which varied with time. Thirdly, the impact coefficient of vehicle for the bridge of Xinxinnan are measured ,and I comparative study on the measured and regression results of the bridge of Xinxinnan. Fourthly, the change law of structural frequency and vehicular impact coefficient under different damage position and damage condition of three-span continuous girder bridge. Lastly, study on the differences of the theoretical value,the measured value and the regression value by the test of the real bridge.