Dynamic Response Of Continuous Girder Bridge Due To High-speed Trains

High-speed railway is a systemic engineering with a wide range of profession and advanced technologies. With economy's rapid growth in China and the proposal of the idea of building a energy-saving society, construction of high-speed railway continues to grow vigorously. In the building of high-speed railway, bridge occupies a large ratio. Bridges in high-speed railway have quite strict requirements of bridge deformations. Also, static designing method, which has currently been adopted in bridge structural design, cannot accurately reflect the interaction between high-speed trains and bridges. That means, only according to empirical formula to calculate impacting coefficient cannot ensure the scientificalness of design, and this problem will become more and more obvious with higher and higher speed of train.Based on Luoshui long-span bridge, which is a 48+80+48m continuous girder bridge in the Wuhan-Guangzhou passenger railway line, in this paper, bridge dynamic response under high-speed train is calculated and analysed. All above results are compared with those results that are calculated through empirical formula in standards, and it shows that current standards do not fully consider. It also provides references for theoretical computation of impacting coefficient of continuous girder bridge, which can guide the design in high-speed railway. Main researching contents are as followed:(1) Use bridge structure dynamics, traffic dynamics and soon to build the analysing model of the dynamic interaction of the system of train and bridge. Based on the principle of total potential energy with stationary value in elastic system dynamics and the "set in right position" rule formulating system matrixes, the overall vibration equation of corresponding vehicle- continuous girder bridge time dependent system is established.(2) Based on the above analysing model, impacting coefficient of three typical sections(sections of the middle of side span, middle span and bearing) under different working conditions are detailedly calculated.(3) Summarize the research results in the paper, and point out the direction of further research in future.