Structures in earthquake-prone areas are not subjected to a single seismic event, but also to a seismic sequence consisting of mainshock and several aftershocks. However, the influence of seismic sequence on performance of structures has not been addressed in majority of existing seismic codes. This paper investigates the effect of repeated earthquakes on performance of steel buckling restrained braced frames. For this purpose, 4-story and 10-story prototype buckling restrained braced frames, designed according to Iranian building codes, are exposed to five seismic sequences. Nonlinear time history analyses are conducted and the responses of frames are measured in terms of maximum inter-story and residual drifts. Furthermore, Park–Ang damage indices and global ductility factors are obtained for braced frames under examined mainshocks and mainshock–aftershock sequences. From the results of this research, it is found that the seismic sequence has the potential to increase the inter-story drift, residual drift, damage index and global ductility factor of buckling restrained braced frames. It is also highlighted that the spectral acceleration of mainshock–aftershock sequence, in comparison to that of single event mainshock, considerably affects the performance of buckling restrained braced frame under repeated earthquakes.

地震多发地区的结构不会受到单一地震事件的影响，还会遭受由主震和几次余震组成的地震序列的影响。但是，在大多数现有的地震规范中，地震序列对结构性能的影响尚未得到解决。本文研究了反复地震对屈曲约束支撑框架性能的影响。为此，根据伊朗建筑规范设计的4层和10层原型屈曲约束支撑框架暴露于五个地震序列。进行了非线性时程分析，并根据最大层间和残余漂移来测量帧的响应。此外，在检查过的主震和主震-余震序列下，获得了支撑框架的Park-Ang破坏指数和整体延性因子。从研究结果可以看出，地震序列有可能增加屈曲约束支撑框架的层间漂移，残余漂移，破坏指数和整体延性因子。还需要强调的是，与单事件主震相比，主震-余震序列的频谱加速度极大地影响了反复地震作用下屈曲约束支撑框架的性能。