中文摘要：

对掉层框架结构上接地柱采用三种常见的支座约束形式，通过改变掉层框架结构所掉跨数，共设计9个算例对山地掉层框架结构进行基于增量动力分析法的易损性分析。结果表明：当掉层结构所掉跨数占结构总跨数比例较大时，三种支座形式超过CP极限状态的概率接近；当掉层结构所掉跨数约占结构总跨数一半时，采用固接支座形式的结构超越CP极限状态的概率最小，抗倒塌性能最好；当使用固接支座形式时，掉层结构超过CP极限状态的概率最小，抗倒塌性能最好。建议当掉层结构所掉跨数较多时使用滑动支座；掉层结构所掉跨数较少时使用固接支座。

英文摘要：

The seismic vulnerability of different constraint conditions of the upper ground columns and different span numbers of dropped stories were discussed in nine calculating examples through the IDA method. The results show that when the span number of dropped stories accounted for great percentage of the total structure span number, the probability over collapse prevention limit condition is proximal in the three constraint conditions; The probability over collapse prevention limit condition is minimum when the supports of upper ground columns are fixed ends. It has better collapse-resistant capacity. When the span number of dropped stories accounted for 50% percentage of the total structure span number, it＇s the best to use fixed ends support because of its minimum probability over collapse prevention limit condition.