Abstract The purpose is to address two issues arising from the frequency dependence of viscoelastic (VE) isolation bearings implemented in base-isolated structures (BIS): (i) how the frequency dependence affects the structural response; and (ii) which method is appropriate for the VE BIS. Effects of the frequency dependence on the absolute acceleration transmissibility are analyzed based on a two-degree-of-freedom system. Three generic algorithms: (i) constant-parameter approximation (CPA), (ii) mode superposition iteration, and (iii) modified rational polynomial approximate (RPA) are used to calculate the seismic responses. Effects of the frequency dependence on the seismic responses of the VE BIS subjected to the historic earthquakes are numerically analyzed through a five-story frame structure. The results show that the frequency dependence of the stiffness can broaden the absolute acceleration transmissibility curve of the VE BIS. The seismic responses in general are underestimated when the frequency dependence is not well considered, and the response errors are influenced by the frequency dependence, excitation characteristics and structural dynamic property. The RPA method takes into account the frequency dependence of VE isolation bearings completely through the rational polynomial model. The CPA and mode superposition iteration methods can only consider frequency dependence effect partially, and the mode superposition iteration method performs better.

中文翻译：

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频率相关性对线性粘弹性基础隔震结构抗震性能的影响

摘要 目的是解决在基础隔震结构 (BIS) 中实施的粘弹性 (VE) 隔震支座的频率相关性引起的两个问题：(i) 频率相关性如何影响结构响应；(ii) 哪种方法适用于 VE BIS。基于二自由度系统分析频率依赖性对绝对加速度传递率的影响。三种通用算法：(i) 常数参数近似 (CPA)、(ii) 模式叠加迭代和 (iii) 修正的有理多项式近似 (RPA) 用于计算地震响应。通过五层框架结构对频率相关性对 VE BIS 经受历史地震的地震响应的影响进行了数值分析。结果表明，刚度的频率依赖性可以拓宽VE BIS的绝对加速度传递曲线。没有很好地考虑频率相关性时，通常会低估地震响应，响应误差受频率相关性、激励特性和结构动力特性的影响。RPA方法完全通过有理多项式模型考虑了VE隔震支座的频率依赖性。CPA和模式叠加迭代方法只能部分考虑频率相关效应，模式叠加迭代方法效果更好。没有很好地考虑频率相关性时，通常会低估地震响应，响应误差受频率相关性、激励特性和结构动力特性的影响。RPA方法完全通过有理多项式模型考虑了VE隔震支座的频率依赖性。CPA和模式叠加迭代方法只能部分考虑频率相关效应，模式叠加迭代方法效果更好。没有很好地考虑频率相关性时，通常会低估地震响应，响应误差受频率相关性、激励特性和结构动力特性的影响。RPA方法完全通过有理多项式模型考虑了VE隔震支座的频率依赖性。CPA和模式叠加迭代方法只能部分考虑频率相关效应，模式叠加迭代方法效果更好。