The Collision Response Of Isolation Bridge In Expansion Joints Under Earthquake Excitation

Simple-supported girder bridge is applied generally on the road and rail and is the hub of urban traffic engineering, which once encountered the earthquake damage, not only can lead to traffic paralysis, but also bring huge economic losses. Therefore, the fortification of the bridge is concerned increasingly by engineering and academia. Researches show that bridges will produce the same longitudinal vibration between adjacent cross in the action of earthquake, and leading to the displacement between cross is greater than the width of gap, which will cause collision of the expansion joints. However, the collision would produce great instantaneous pulse force, maybe bring the local failure of collision parts, and lead seriously to the collapse of the bridge. So it is necessary for bridges to make analysis of collision response.In the paper, we take three spans(18m+20m+18m) of simple-supported girder bridge as the engineering background and makes dynamic time history analysis of the action of collision in the earthquake. On the basis of important theoretical research of collision, Kelvin collision model was used to simulate the contact element, and by using the software ANSYS to establish finite element analysis model of the whole bridge, which finds out the general law of collision effect, studies seismic response of the bridge in the change of these collision parameters. The paper mainly introduced the following several aspects:(1) Introducing the collision damage of bridges in recent decades in the earthquake and clarifying the significance of the subject and research status at home and abroad.(2) Summarizing the calculation method of bridge seismic and collision theory, selecting suitable model of this paper by making detailed analysis of the existing collision model, and finite element analysis model of the whole bridge.(3) Appropriate seismic wave is selected and adjusted. Making numerical analysis by changing the related factors of influencing the collision in the finite element software ANSYS.(4) The result of the calculation was made correlative analysis, and sketched the existing engineering measure of preventing collision.