中文摘要：

上接地柱为山地掉层结构的薄弱部位,掉层结构的破坏模式表现为上接地柱的率先破坏。对普通框架、掉层框架、带拉梁的掉层框架和采取改进措施的带拉梁掉层框架4个算例进行大震弹塑性分析和易损性分析,对比各结构的破坏模式和改进措施的效果。结果表明：与普通框架结构相比,普通掉层框架抗倒塌能力较弱,上接地楼层柱延性需求很大,大震下率先发生破坏;增设拉梁对掉层框架结构的破坏模式有一定的影响,但效果不太理想,且增设拉梁不能提高结构的抗地震倒塌能力;采取改进措施的带拉梁掉层框架结构效果非常显著,破坏模式和抗地震倒塌能力接近于普通结构。

英文摘要：

The typical failure of moment frames with dropped stories is caused by the failure of upper ground story columns.Four model frames were designed and numerically analyzed to evaluate their seismic performance and improvement effect.Research results indicate that the seismic collapse-resistant capacity of frame with dropped stories is weaker than that of general structure.The ductility of upper ground story columns is high for moment frames with dropped stories,which would be destroyed under rare earthquake;the addition of tensile beam has certain influence on the failure mode of moment frames with dropped stories,but not significant.The seismic collapse-resistant capacity of frame with dropped stories can not be improved by the addition of tensile beam.The effect of the failure mode and the seismic collapse-resistant capacity of moment frames with dropped stories and the improved measure are remarkable.This is closer to the common structure.