The Collision Simulation Analysis On Bridges In Mountainous Areas Combined With The Site Conditions

With the demands of economic development and transportation, more and more bridges are located in different mountainous terrain. And all previous earthquakes make us know that because of the influence of the mountainous terrain conditions or the special site environment, the bridges in mountainous areas always suffered more from seismic damage than that in plain areas. Bridges in mountainous areas mainly are beam bridges which usually suffer collision damages under seismic excitation. Therefore, it is necessary to make a study on the collision response of bridges in mountainous areas combined with the site conditions.With reasonable calculation parameters, three-dimensional finite approaches and finite element software---midas FEA and midas civil, and by setting up a joint model of terrain and bridge based on the four kinds of common terrain in mountainous areas:basin-shaped concave terrain, piedmont diluvial terrain, wavy terrain and deep valley terrain, this paper, with time history analysis, calculated the surface point acceleration response of the terrain model and the collision response of bridge structures under seismic excitation with considering the impact of site environmental and without considering the impact of site environment.The results of the calculation indicate:the site environment has remarkable influence on the seismic response of the structures. Different site environment differ greatly on the seismic response of the surface points. And with considering the impact of site environment, the collision response is stronger than that without considering the impact of site environment, which means that the site environment has the effect of amplification on the collision response of bridges and the extent of amplification is related to the peak and shape of the acceleration time-history curve of the surface point. Meanwhile different types of bridges are different from each other in collision response. The collision force of simply supported girder bridges is limited, but with more frequency of collision. The collision force of continuous girder bridges is bigger, and the collision is more complicated. Though with limited times of collision, the collision force of rigid frame bridges is very high.