Highway Bridge Vibration Under Traffic Loads Studied

With the economic fast development, highway transportation is more and more important in national economy and life. Because modern bridges' structures are developing on high pier, long span, thin and light structure, it is outstanding that the study on vibration response of the highway bridge carried by vehicle. It becomes one of the most important researches. In this aspect, people have already carried on a great deal of theoretical investigation and empirical analysis, but there are still some problems. In this paper, a deeper study will be done, after summed up the result of the research from predecessors. The major work and some new aspects are as follows.First of all, this paper gives an overview of early calculations about bridge vibration caused by vehicle (because these methods are simple and accurate in their theory category, they are still using now) and modern finite element method. Some problems are pointed up to solve, which are building mathematical model and computational efficiency. And introduce ANSYS, particularly Transient Dynamic module and Newmark method for solved vibration differential function of discrete structure.Second, the bridge-vehicle system was modeled as beam-moving load. By applying D'Alembert's principle, the coupled vibration functions were derived under considering the effects of road surface roughness and different vehicle speed. Discuss and analyze bridge vibration response. Then, point out this method's limitations.Third, applying step by step integration, introduce a new way to solve vehicle-bridge coupled system base on ANSYS. With computing different element model and load time, make sure this way's feasibility and accuracy, especially large-scale bridge.Last, using this new coupled method, compute and study bridge vibration from a real bridge. Analyze displacement response about this bridge, with different loading combinations through the bridge. And discuss some factors which influence the results. Some valuable conclusions are got.