关于完善甲类建筑防震标准的思考

本文认为,宜按设计使用年限之不同,将甲类建筑由设计使用年限100年的甲A类和设计使用年限为50年的甲B类,分别确定设防地震的概率水平.考虑到国家抗震设防政策的延续性,并结合我国地震危险特性,甲A类建筑3个设防地震的重现期宜取200年、2000年和5000～10000年;甲B类建筑3个设防地震的重现期宜取100年、100...

Discussion on improving criterion of aseismatic design for class A buildings

Class A buildings are suggested to be divided into 2 categories, class Aa and class Ab, subjecting to their design service periods of 100 years and 50 years, respectively. The seismic fortification probability levels for class Aa and Ab buildings ought to be different. Taking into account the continuity of the aseismatic design policy and the characteristics of seismic hazard in China, the 3 presumed recurrence periods of earthquakes in aseismatic design for class A, buildings ought to be 200, 2000 and 5000-10000 years, respectively. For class Ab buildings, the recurrence periods ought to be 100, 1 000 and 2 500-5 000 years. In terms of exceeding probability in design service period, they should be 40%, 5% and 1%-2%. These suggestions guarantee the consistency of seismic safety level for class A buildings with different design service periods, and make it different from class B and class C buildings, for which the exceeding probability is 63%, 10% and 2%-3% in 50 years. This also satisfies the requirement that the PGA of level 1 earthquake should not be less than 1/3 of that of level 2. The suggestions of this paper should be useful for improving criterion of aseismatic design for class A buildings.