高墩自复位隔震机理

Isolation mechanism of self-centering tall pier

为了探讨桩基础高墩自复位隔震机理,用2个弹簧模拟桥墩的提离摇摆,考虑限位钢筋的影响,基于某铁路高墩桥梁,采用非线性时程分析方法,输入3条强震记录,讨论高墩摇摆反应随提离弹簧刚度、基础宽度及参数λ变化的规律。研究结果表明:提离弹簧刚度越小桥墩的摇摆振动越剧烈、摇摆反应越大,墩顶位移随λ的增大而减小、有明显的线性关系,墩底弯矩随λ的变化相对复杂。通过基础宽度、λ及墩-承台的接触刚度调整均可以实现对桥墩摇摆反应的控制。

The isolation mechanism for self-centring tall pier with pile foundations was investigated. Two springs were used to simulate the uplift and rocking of the pier. Rocking response of a railway tall pier was investigated through nonlinear time history analysis by inputting three strong ground motions, considering effects of restrainers on the rocking response. The rocking responses of the pier were discussed such as fimctions of the stiffness of up-lift spring and width of spreading foot. The results show that the rocking vibration is severe and rocking response of the piers is larger when the stiffness of lift-off spring is smaller. The base moment increases along with 2. The displacement at pier top decreases while 2 increases. It is also observed that displacement at pier top has a linear relation with 2, but the .relation between base moment and 2 is relatively complicated. Rocking response of the tall pier can be controlled by adjusting the width of foundation, 2 and the contact stiffness between the pier and the pile cap.