大跨空间结构竖向变刚度三维隔震装置及其隔震性能研究

本文中研制了一种适用于大跨空间结构的竖向变刚度三维隔震装置,该装置由用于水平隔震的铅芯橡胶支座和用于竖向隔震的组合液压缸构成。基于液压原理,通过改变组合液压缸不同阶段参与工作腔室的种类和数量实现装置竖向变刚度特性。推导了组合液压缸不同工作阶段的刚度计算公式,并建立了其滞回模型。完成了组合液压缸的振动台试验,验证了刚度计算公式与所建立滞回模型的准确性。采用有限元方法,对比分析了不同地震作用下单层球面网壳结构在不隔震、水平隔震、非变刚度三维隔震与竖向变刚度三维隔震时的响应,建立了考虑水平地震影响的最大竖向隔震位移计算方法。结果表明,竖向变刚度三维隔震装置对结构加速度与杆件内力的减震率优于水平隔震支座,与非变刚度三维隔震装置接近,但可更有效地限制隔震层竖向位移与结构倾覆转角;所建计算方法可以准确计算结构三维隔震时的最大竖向隔震位移,不同地震记录作用下计算结果的最大误差为16.0%。

Research on isolation performance of three-dimensional isolation device with vertical variable stiffness for long-span spatial structures

This paper proposes a three-dimensional (3D) isolation device with vertical variable stiffness for long-span spatial structures. The device is composed of a lead rubber bearing to isolate horizontal vibrations and combined hydraulic cylinders to isolate vertical vibrations. The vertical variable stiffness characteristic is realized by controlling the participation of different champers in combined hydraulic cylinders. A analytical model for calculating the stiffness of combined hydraulic cylinders at different working stages is proposed, and a hysteretic model is established. Shaking table tests are conducted to verify the proposed hysteretic model and the vertical variable stiffness mechanism. The responses of single layer spherical reticulated domes with different isolation solutions, namely, no isolation, horizontal isolation, 3D isolation with linear vertical stiffness and 3D isolation with vertical variable stiffness, are analyzed using finite element method. The performance of the 3D isolation device with vertical variable stiffness is investigated and a calculation method for the maximum vertical isolation displacement considering the influence of horizontal earthquake is established. The results show that the three-dimensional isolation with vertical variable stiffness can better control the structural acceleration and internal force of the bars comparing to the horizontal isolation; it has similar control effect with the, 3D isolation with linear vertical stiffness and can limit the isolation displacement and overturning angle. The calculation method can accurately calculate the maximum vertical isolation displacement with a maximum error of 16.0%under different ground motions.