Seismic Pounding Response Analysis Of The Simply Supported Beam Bridges Of High Speed Railway Under Strong Earthquakes

Seismic disaster is ferocious than a tiger, humans pay a lot in the previous earthquake. As a result of rapid economic and social development,high-speed railway bridges play a more and more important role in people's daily life. And as the urban transportation lifeline project, high-speed railway bridge work of earthquake resistance and disaster prevention is extremely important. When the strong earthquake comes,bridge structure will easily occur a great displacement on vertical and horizontal directions,and then causing collision effect, resulting to damage of the upper end of the bridge structure, bearing failure, the damage of expansion joint and off the beam.In this paper, the research of the impact response of the high-speed railway bridge in the strong earthquake is based on the background of the actual project,the following main work and achievements are included:(1)On the basis of collecting a large amount of data, the paper summarizes the common occurrence of the bridge in the earthquake, and summarizes the current situation of the bridge collision.(2)This paper introduces the theory and method of the bridge collision problem, summarizes several common collision models, and introduces the simulation method by SAP2000.This peper establishes a 3-span high-speed railway simply supported beam bridge model and introduces the bearing,collision cell in SAP2000 simulations and damping structure determined respectively; according to the requirement of our country standard selected three typical natural waves and a artificial wave as the collision analysis of seismic waves,conducted to analysis the structure modal;and established two models,namely considering and without considering the collision, to enter earthquake wave along the bridge, comparative analysis of the two model collision of bridge structure seismic response effect. The results show that the impact on seismic response of bridge structure impact can not be ignored, collision response must be considered in the bridge structure dynamic response analysis.(3)For deep soft soil area,this paper establishs the pile-soil interaction model, studys the effect of the pile-soil interaction on the collision response of the high speed railway bridge.The results showed that the beam collision response of pile-soil interaction is very obvious. For the deep water area,the moving water pressure on bridge structure to collision reaction is obviously,once considering the moving water pressure, the pier top displacement,reaction force of pier bottom, the beam of relative displacement,and collision force of bridge structure increased by a different degree, collision times also increased.(4)The paper analyses the effect to collision force about expansion joints spacing of size on beam, collision stiffness, adjacent bridges and hydrodynamic pressure. The results showed that the effect of expansion joints spacing of size on beam collision force is very big, and the collision force will increased with the space increasing, over the limit space, no collision occurred; the effect of collision unit stiffness on beam collision reaction is big, the collision force increases with collision unit stiffness increases, collision times variable less; the effect of Pier high ratio and Pro beam of stiffness on structure earthquake collision reaction are large,when the pier height ratio is 0.6, the expansion joints beam collision force reach peak maximum, collision times also increase.With the pier height ratio increases, the peak variable of beam collision force decreases.When the pier height ratio is 1.0, pro across period ratio is consistent,the times of collision on beam end occurred at least.(5)The paper discusses the anti-impact measures of high-speed railway bridges, and analyses the influence of the parameters of viscous dampers on the collision response.