A Study on the Seismic Load on the Safety of Buildings and Social Allowable Damage of Buildings

在地震灾害的预防中，最重要的是减少在社会允许影响下的地震破坏。社会影响可以通过报纸上地震损失报道的数量来估计。对1945 ~ 1995年28次地震的震害报道与总报道的比率进行了震后14天的调查。地震后报告率呈指数级下降。据估计，社会允许的死亡人数上限约为25人。利用构造震源，用概率方法分析了日本地震危险度图。地震发生模型是根据地震目录修正后的震级分布确定的。利用这些参数计算了最大加速度和速度的地震危险性图。利用神户地震的地震危险性模型和结构强度模型，分析了日本694个城市的木结构房屋在社会允许范围内防止结构地震破坏的结构地震荷载的地震城市因子。当地震动比为1.7时，城市因子估计为1.6。但是，当建筑比增加到16时，城市系数估计为1.8。建筑物数与城市因子的相关系数高于地面最大速度的相关系数。

The most important thing in the prevention of earthquake disaster is to reduce the seismic damage under social allowable impact. The social impact can be estimated by the amount of seismic damage report in newspapers. The report ratios of seismic damage report to total report in newspapers about 28 earthquakes from 1945 to 1995 are surveyed for 14 days after earthquakes. The report ratio exponentially decreases after earthquake. The social allowable limit is estimated about 25 dead persons.Seismic hazard maps in Japan are analyzed by the probabilistic method using the seismic sources by the tectonics. Seismic occurrence model are determined from the modified magnitude distributions by the earthquake catalogs. The seismic hazard map of the maximum acceleration and the velocity are calculated using these parameters.A seismic urban factor of the structural seismic load to prevent seismic structural damage in the social allowable limit is analyzed for the wooden houses in 694 cities in Japan using the seismic hazard model and the structural strength model obtained by the Kobe earthquake. The urban factor is estimated as 1.6 when ground motion ratio 1.7. However, the urban factor is estimated as 1.8 when building ratio grows up to 16. The correlation coefficient of number of buildings to the urban factor is higher than that of ground maximum velocity.