In this article, the effect of mainshock-aftershock sequences on the seismic performance of ordinary reinforced concrete frames (ORCFs) retrofitted by fiber reinforced polymers (FRPs) is studied. Various mainshock damage levels are used to precede aftershocks that are incrementally scaled to drive the studied structures into the collapse state. The mainshock damage is represented by the maximum inter-story drift (MID) parameter, and aftershock scaling is performed following incremental dynamic analysis (IDA) procedure. The derived collapse capacities are evaluated to study the effect of the mainshock and the retrofit action. The obtained results indicate that while the retrofit program is effective in elevating the collapse capacities of the structures, the capacity reductions caused by various mainshock damage levels in the studied structures are independent of the structures strength and ductility capacities. Rather, these capacity reductions were attributed to structures’ inherent plastic behavior mechanisms, including concrete cracking and reinforcement yielding.

本文研究了主震-余震序列对纤维增强聚合物（FRPs）加固普通钢筋混凝土框架（ORCF）抗震性能的影响。在余震发生之前，先采用各种主震破坏水平，然后再按比例缩放余震，以将所研究的结构推入倒塌状态。主震破坏由最大层间漂移（MID）参数表示，余震缩放遵循增量动态分析（IDA）程序执行。评估得出的倒塌能力，以研究主冲击和改型作用。获得的结果表明，尽管改造程序可以有效地提高结构的倒塌能力，在研究的结构中，由各种主冲击破坏水平引起的承载力降低与结构的强度和延性承载力无关。相反，这些能力的下降归因于结构固有的塑性行为机制，包括混凝土开裂和钢筋屈服。