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1 前言 不同研究者已提出了各种估算结构系统对地震激励的最大反应的方法。Drenik(1970,1973)提出过一种想法,可以利用表征地面运动的,变化范围很大但个数有限的确定性信息,来求取结构系统对地震的最不利反应。利用地震在结构位置上可能输入的总能量,在使结构反应最大的可能的动力集合范围内,寻求一个“临界激励”,然而,由于只限制了总能量,因此结构相当保守。Shinozuka(1970)建议通过限定傅氏幅值谱的包络来表示地震激励。由于这一方法中所包含的信息大大地限制了可能的激励集合,因此由之得到的结果的保守程度比Drenick的要小得多,因此结构最大反应值也减小了。Admadi(1986)求出了水平、竖向组合地震地面运动作用下,弹性结构最大反应的几个里耶普诺夫限值。然而,该法需要了解最大地面加速度的合适的有效持时。除上述估算地震中结构最大反应的方法外,还提出了统计方法(Biot, 1941; Housner, 1959; Newmark,1973)和概率方法(Crandall, 1966; Vanmarcke, 1972)。 由于与破裂过程有关的震源效应,与震源到场地间波传播有关的路径效应和与场地
1 Introduction Various researchers have proposed various ways of estimating the maximum response of structural systems to seismic excitation. Drenik (1970, 1973) proposed an idea that can use the deterministic information that characterizes ground motion, but with a large range of variations but limited numbers, to find the most adverse reaction of structural systems to earthquakes. Using the total energy that the earthquake may input at the structure location, a “critical excitation” is sought within the range of possible power sets that maximize the structural response, however, the structure is rather conservative because it only limits the total energy. Shinozuka (1970) suggested that seismic excitation be expressed by defining the envelope of the Fourier magnitude spectrum. Since the information contained in this method greatly constrains the possible set of incentives, the resulting results are much less conservative than Drenick’s, and therefore the maximum response value of the structure is also reduced. Admadi (1986) obtained a few Riyprev limits for the maximum response of elastic structures under horizontal and vertical combined ground motions. However, this method requires knowledge of the proper effective duration of maximum ground acceleration. In addition to the above method for estimating the maximum response of structures in earthquakes, statistical methods (Biot, 1941; Housner, 1959; Newmark, 1973) and probability methods (Crandall, 1966; Vanmarcke, 1972) were also proposed. Due to the source effect associated with the fracture process, the path effects associated with the propagation of the source to the inter-site wave and the site