新型三维隔震墩隔震单元参数设计研究

Research on design of the element of seismic isolation for a new three-dimensional seismic isolation pier

竖向地震作用对结构的影响不容忽视,如何有效的同时减小竖向与横向地震作用具有现实意义,三维隔震墩能够同时隔离水平及竖向地震作用,但其设计理论并不完善,如何确定合适的弹簧参数从而达到理想的水平与竖向隔震效果并不明确。本文推导了螺旋弹簧竖向刚度及考虑轴向荷载和水平荷载时弹簧的水平刚度公式,基于弹簧力学特性提出了隔震单元参数设计方法以及各参数取值范围。研究表明:弹簧自由长度与中径之比在[1.6 2.61]之间时弹簧不会发生失稳现象且弹簧水平刚度随竖向位移增大而减小;弹簧中径及自由高度越大、材料直径在满足强度的情况下隔震效果越好。本文对1栋8度设防的隔震结构进行隔震单元设计并进行时程分析,结果表明:竖向减震系数为0.6,水平减震系数小于0.4,隔震效果显著。

In this paper, the formulas of vertical stiffness lateral loading were derived. Based on these formulas we dimensional seismic isolation pier and the range of these and horizontal stiffness of spring combined with axial and proposed a method for the design of parameters in three- parameters. Research shows that helical springs will not occur vertical instability when ratio of free length and middle diameter of spring ranges between 1.6 and 2.61. Furthermore, the horizontal stiffness of the spring decreases with the increase of the vertical displacement. The greater the diameter and height of the spring, the better the isolation effect is. In addition, in this paper, the design of an eight-degree fortification of the isolated structure was carried out, and the seismic decrease coefficient was calculated. Results show that horizontal seismic decrease coefficient could be controlled under 0.4 when vertical seismic decrease coefficient is 0.6, and the isolation effect is remarkable.