【摘要】 为分析地震作用下大型桥梁高桩基础的运动特性,首先以苏通大桥5号桥塔的基础为工程对象,建立土层-桩基础相互作用体系的有限元模型。然后结合苏通大桥5号桥塔基础所在场地,以采用滞后阻尼模型条件下苏通大桥5号桥塔处自由场的地震动响应为基准,讨论了如何在有限元程序中合理考虑土层在地震激励条件下的阻尼特性。最后在此基础上确定土层-桩基础相互作用体系有限元模型的阻尼参数,并进行基岩一致水平激励下的桥梁桩基础承台的地震响应分析。数值结果表明,桩基础承台的运动以刚体运动为主,可用水平方向上的刚体平动,两侧承台中心处的竖向刚体平动和刚体转动来近似描述。更多还原

【Abstract】 To analyze the motion characteristics of large-scale bridge’s pile foundation under earthquake,the finite element model of soil-pile foundation’s interactional system was established firstly as with the engineering object of No.5 tower’s foundation of Sutong Bridge.Then,by setting the result using hysteretic damping method as the compared datum,the question that how to imitate the damping characteristic of soil subjected to seismic excitation in finite element program was discussed as to the result of seismic response of Sutong Bridge’s No.5 tower’s free field.Obtaining damping parameters of this model,the motion characteristics of seismic response of this system under uniform excitation of horizontal bedrock ground motion can be analyzed.According to the results,the two caps of pile foundation bear rigid characteristics in response,which can be depicted approximately as the rigid horizontal translational motion,as well as the rigid vertical translational motion and rigid rotational motion of the center of each cap.更多还原