丙类与乙类设防RC框架结构抗地震倒塌能力对比

按照GB 50011-2001《建筑抗震设计规范》6～8.5度的丙类与乙类设防要求分别设计了10个典型RC框架结构算例，采用基于动力增量时程分析(IDA)地震倒塌易损性分析方法得到了各算例结构在遭遇罕遇地震和特大地震时的倒塌率，据此对不同设防烈度的丙类和乙类RC框架结构的抗地震倒塌能力进行了评价分析。研究指出，结构的抗倒塌能力需根据结构的绝对抗震能力和相对地震动强度来进行评价。分析结果表明，对于6～7.5度抗震设防的结构，因其绝对抗震能力偏低，抗震设防烈度仅由丙类提高到乙类，其在遭遇特大地震时的抗地震倒塌能力仍较差，需采取进一步的措施增强其抗震能力。

Comparison of collapse-resistant capacities of RC frames with seismic fortification categories B and C

According to the GB 50011-2001‘Code for seismic design of buildings’, 10 typical reinforced concrete (RC) frames were designed with different seismic fortification levels (from 6 to 8.5) and different fortification categories (B and C). The collapse resistances of the frames were evaluated quantitatively with collapse fragility analysis that was based on incremental dynamic analysis (IDA). The collapse resistances of frames with seismic fortification categories B and C were compared. The results show that the collapse resistances of structures should be evaluated in accordance with both the actual seismic resistance and the corresponding design intensity. For frames with seismic fortification level 6 to 7.5, since their actual aseismic resistances are relatively weak, their collapse resistances are insufficient when their seismic fortification categories are upgraded from B to C. So further measures are needed to enhance these structures.