不同地震水准反应谱之间的关系和罕遇地震作用设计反应谱的确定

不同地震作用水准的设计反应谱长期以来一直采用各水准谱形完全一致的假定。这与地震危险性分析的一般结论不符。《建筑抗震设计规范》(GB50011-2001)对此作出了修订。本文基于设计反应谱的三参数标定模型推导了罕遇和多遇地震作用设计反应谱的关系，指出两者谱值之比在高频、中频和低频段分别对应于峰值加速度、速度和位移之比。引入地震动衰减规律进行了罕遇和多遇地震作用设计谱关系的近似估计，提出了基于多遇地震作用设计谱确定罕遇地震作用设计谱的调整方案，验证了现行规范将反应谱特征周期适当延长以得到罕遇地震作用设计谱的做法的合理性。

Relationship between design response spectra for differcnt earthquake levels and determination of design response spectra for rare earthquake level

It is known that building structures should be designed to have different performance under different earthquake levels. An important thing which has been ignored up to now is that the shapes of design response spectra for different earthquake levels are not uniform according to the attenuation laws of ground motions. Employing the three parameters model of design response spectra presented by Newmark and Hall, the relationship between design response spectra for rare and frequent earthquake levels is derived theoretically. The relations between parameters defining the shapes of response spectra are then evaluated quantitatively by introducing the typical attenuation laws of response spectra in China. Based on the design response spectra for the frequent level defined in the Code for Seismic Design of Buildings of China, the design response spectra for the rare level are suggested. It is convenient that the characteristic periods of spectra for rare level may be adjusted to be 0.05sec larger than those for frequent level in the same site.