周期性隔震基础的优化设计与试验验证

周期性隔震基础是利用周期性结构的衰减域特性,将地震动与上部结构自振频率接近的频率范围内的能量衰减,从而控制上部结构响应的新型隔震装置。周期性基础的隔震性能受到多方面因素的影响,包括局域共振子的调谐频率比、质量比、阻尼比、基体的刚度、上部结构与基础的相互作用以及地震动的频谱特性等。目前尚未有研究综合考虑上述因素的影响并提出周期性基础的设计方法。提出以一组地震动作用下上部结构峰值响应衰减率的平均值为目标函数,对周期性基础进行优化的设计方法。计算结果表明,按照该优化方法得到的周期性基础对上部结构在选取的44条地震动作用下,峰值响应的平均衰减率达30%。参数敏感性分析表明,优化设计得到的周期性基础对于自身参数的变化具有良好的鲁棒性。最后利用缩尺振动台试验验证了优化设计得到的周期性基础的隔震性能,证明了优化方法的有效性和优化结果的正确性。

Optimal design and test of periodic foundation

The idea of employing periodic foundations (PFs) to mitigate seismic damage to superstructure relies on attenuating seismic waves’ energy around the superstructure’s Eigenfrequency. The seismic mitigation performance of PFs depends on several aspects, including the tuning frequency ratio of inner resonators and their mass ratios and damping ratios. The stiffness of host material, the reaction of superstructures and frequency components of seismic waves also influence the performance of PFs. An optimization design method based on the average reduction of peak responses of a superstructure under excitations of several selected seismic waves is proposed. The result indicates that the peak responses of the superstructure under 44 selected seismic waves are averagely reduced by 30% by the optimal PF. Parametric studies indicate that the performance of the optimal PF is robust concerning to parameter deviations. The effectiveness of the design method was proved by a small scaled shaking table test.