Fundamental Study on Probabilistic Evaluation of Earthquake Load

地震反应的概率估计考虑了许多方面。本文首先提出了一种改进的地震危险性分析方法，即利用发生在板块边界上的地震孤立模型，并假定地震地面运动的最大速度的适当上界。针对不同类型的模型，提出了动力响应临界输入波的生成方法。对于面向原点的迟滞模型，使用频率分量的线性相位特性，而对于正常的双线性迟滞模型，使用使时程在等间隔时间内产生较大值的相位特性。两个对数正态变量和的畸变函数近似为具有所提参数的对数正态分布。用蒙特卡罗方法对一些检查点的逼近精度进行了检验。微震测量表明，现有建筑的固有频率较短，高模态的阻尼比小于设计中使用的阻尼比。对高层建筑动力性能的质量刚度比、屈服剪力系数等参数进行了统计检验。考虑参数的高度分布，分别以S结构的6个模型和RC结构的5个模型展示了具有代表性的动力模型。这些模型的地震安全可靠度指标在2 ~ 3之间。以总成本最小为原则，在可靠性最优的基础上，提出了具有适当安全度的设计峰值地加速度。本文还综述了这些结果之间的关系。

Many aspects for the probabilistic estimation on the erathquake response have been considered. At first an improved seismic hazard analysis is proposed by the use of an isolated model of earthquake occuring on plate boundaries and by assuming appropriate upper boundary of maximum velocity for the earthquake ground motion. Generation methods of the critical input wave for dynamic responses are developed for various types of models. For origine oriented hysteresis models linear phase properties to the frequency components are used and for normal bi-linear hystresis models a phase property which causes large values of the time history with equally spaced time interval is used. The distoribution function of the sum of two log-normal variables is approximated by a log-normal distribution with proposed parameters. The accuracy of the approximation is examined by the Monte-Carlo method for some check points. It is recognized by micro-tremore measurements that the natural frequency of existing buildings is shorter and the damping ratio is less for higher modes than those used at the design. Parameters on dynamic properties of tall buildings, i.e.the mass-stiffness ratio and the yield shear force coefficient and so on, are examined statistically. Representative dynamic models are demonstrated by 6 models for S structures and 5 for RC structeres by considering distributions of these parameters to the hight. Reliability indeces for the seismic safety of those models are revealed as between 2 and 3. Design peak ground acceleration is proposed with the appropriate safety degree based on the optimum reliability due to minimum total cost concept. The relation among those results summarized here is also reviewed.