摩擦摆支座等效线性化参数及隔震设计方法研究

Study on Equivalent Linearization Parameters and Base-isolation Design Method of Friction Pendulum System

首先推导了摩擦摆支座的水平和竖向恢复力公式,讨论了水平位移对竖向恢复刚度的影响;其次针对目前摩擦摆支座隔震设计、分析中存在的不足,重点讨论了基于规范设计反应谱迭代求解其等效线性化参数的实施流程和需要注意的问题;提出了一种综合隔震周期目标和摩擦力影响粗定等效曲率半径,并根据静轴力分布情况选择摩擦系数大小的摩擦摆支座隔震方案布设方法;最后结合实际工程案例,对比分析了橡胶支座隔震方案和摩擦摆支座隔震方案在不同组合工况下对支座内力、位移的隔震效果及其分布情况。结果表明:两种隔震方案均能达到降度设计的隔震目标,后者由于受三向耦合影响,各支座上的内力分布较前者的离散性更大;摩擦摆支座有可能出现受拉现象,应用中需注意设置抗拉构造措施;摩擦摆支座隔震方案中应重视空间扭转问题和控制支座抬升量。

The formulas of horizontal and vertical resilience of friction pendulum system were derived and the influences of horizontal displacement on vertical restoring stiffness were discussed. Subsequently,according to the drawbacks in the existing base-isolation design of the friction pendulum system,the implementation process and issues needing attention in the iterative solution of the equivalent linearization parameters based on the standard design response spectrum were emphatically discussed.Meanwhile,an isolation scheme for a friction pendulum system was developed,which determined the effective radius of curvature by considering the influences of the expected isolation period and friction effect,and selected the friction coefficient on the basis of the distribution of static axial force. Finally,combined with a practical engineering case,some factors such as the isolation effect,distribution of internal force,and displacement between rubber bearing and friction pendulum system under different combination conditions were compared and analyzed. As a result,the two schemes can achieve the goal of intensity reduction design. The internal force distribution on each support in the latter scheme is more discrete than that in the former due to the influence of three-directional coupling. Tension phenomenon may occur in the friction pendulum system,so tensile structures are necessary for practice.Attention should focus on the spatial torsion problems and control the bearing lifting amount in the isolation scheme of the friction pendulum system.