罗文斌  钱稼茹　（清华大学土木工程系  北京 100084）

[提要]  通过大量计算分析，探讨了地震作用下弹塑性单白由度体系位移延性系数 μ_△与特征强度比c_y，屈服位移△_y，之间的关系，建立了单自由度体系的 μ_△－c_y－△_y，曲线，即特征延性系数谱。提出了两种确定钢筋混凝土框架的屈服基底剪力和屈服顶点位移方法。探讨了通过多－单自由度体系转移，利用特征延性系数谱和结构的弹性参数求解规则均匀框架弹塑性目标位移的方法。还给出了一个12层规则RC框架目标位移计算的算例。
[关键词]  特征延性系数谱地震响应  目标位移  混凝土框架结构  基于位移的设计

By large amount of calculation,the relations among the displacement ductility ratio μ_△, the yield displacement △_y and the characteristic strength ratio c_y of SDOF system under earthquakes are studied.The μ_△－c_y－△_y spectrum, namely characteristic ductility ratio spectrum( CDRS), is established. Two methods of determining the yield base shear and the yield top displacement of RC frames are suggested. By transferring of elastic MDOF system to SDOF system,and elastic-plastic SDOF system to MDOF system, and by using CDRS, the inelastic displacement demand of regular RC frames can be determined by the elastic parameters of the structure.The approach for estimating the target displacement of RC frame is illustrated by a 12-storey RC frame sample.
Keywords:  characteristic ductility ratio spectrum( CDRS); seismic response;  target displacement;  RC frame;  displacement-based design

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