| The bridge has the phenomenon that the collision occur between the adjacent superstructure of the bridge during earthquake, which would led to the damage of the bridge superstructure or even the collapse of the bridge. In the past, we often saw that the damage phenomenon of the bridge in most of the earthquake records. Keep this in mind, it is necessary that consider the effect of the collision on the seismic response of the bridge in the seismic analysis of the bridges. However, the collision problem is a kind of the contact problem, that is the strong nonlinear and with many of the factors which is inter-coupling. Therefore, It is very difficult that the accurate description of this problem and the response of the collision problem. The collision effect for the bridge should be combined with that the characteristics of the bridge engineering for the bridge seismic in the bridge seismic analysis. That has received attention by many scholars and made a lot of research results of the collision problem, which with the development of bridge construction, the bridge seismic analysis and the refinement design theory. We could found that the treatment of bearings are relatively simple, which failed to consider the complexity of the bearing stress-strain state of the bearings under strong earthquake and its effect on the bridge collision, when made a general survey of many of the existing domestic and international research results of the collision of the bridges. Therefore, that was necessary to improve model more accurate simulation of the collision phenomenon of bridges with take the bearings of bridge to accurately reflect the effect of collision.In this paper, study of a third-span girders bridge, establish its full-bridge finite element model and add the refinement model of collision to that. The research of the response of the collision of the adjacent upper structure of the bridge system, through that time history analysis under the longitudinal earthquake motion, using ANSYS software. The following is the mainly area.1. The overview of the existing model of the collision cell that based on the collision theory, and used the Kelvin model as the collision cell of the full-bridge model in this paper. On this basis, we discussed the impact of the different stiffness and damping of the collision cell for the collision force between the bridge superstructure and the seismic response of the bridges. 2. That the more reasonable and precise bearing unit has been used, according to the practice of engineering. That has two situations the response of bearing model during strong earthquakes:First, they shows the nonlinear characteristics when the bearing units in the horizontal direction into the yield stage that due to lateral loads coming from the upper structure,; second, there would have the relative sliding when the upper transverse momentum generated by movement over the friction of bearing. Under these circumstances, this paper correctly reflect the impact effect of the collision, through that to be able to accurately describe the bearing during earthquake with the establishment of 3-D bearing units.3. Explore the impact of the bridge seismic response with the effect of the collision, based on the comparative analysis of two models that considered the impact of the collision and did not.4. Select different parameters of the model, Analysis of the impact of the collision on the seismic response of the bridge. These parameters include that the size of the gap at the expansion joints of the bridges superstructure, properties of the bearing, characteristic period ratio of this pier and adjacent beams of the bridge and the different seismic waves。5. Describes the major measures that prevent the collision in the practical engineering, Analysis of the principle and effect of several measures to prevent the collision. |
