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一、前言基底隔震系统在地震工程界已受到极大的重视。已经出现了许多隔震方案,像弹簧质量系统、柔性底层概念,特别是滚轴隔震系统和迭层钢板橡胶支座。曾采用过许多模型研究隔震系统的效果。最近,文献(L. Su, G. Ahmadi and I. G. Tadjbakhsh, 1989)中利用数学模型对那些物理模型进行了分类。作为最简单的一个模型,Younis与Tadjbakhsh(1984)、Westermo与Udwadia(1983)和Crandall等(1974)都采用过图1(a)所示的在基础上滑移的一个刚块。当模型受谐和激励时,可以观察到刚块随时间作周期运动。这个周期运动由三个不同的
I. INTRODUCTION The basement isolation system has received a great deal of attention in the seismic engineering community. A number of seismic isolation solutions have emerged, such as the spring-mass system, the concept of a flexible floor, and in particular the roller isolation system and laminated steel rubber bearings. Many models have been used to study the effectiveness of seismic isolation systems. Recently, the physical models were classified using mathematical models in the literature (L. Su, G. Ahmadi and I. G. Tadjbakhsh, 1989). As the simplest model, Younis and Tadjbakhsh (1984), Westermo and Udwadia (1983), and Crandall et al. (1974) have all adopted a rigid block that slides on the basis shown in Fig. 1(a). When the model is excited by harmonics, it can be observed that the rigid block moves periodically with time. This cycle of movement consists of three different