Following an earthquake event, the safety of continued occupancy in terms of whether a mainshock-damaged building could withstand upcoming strong aftershocks is a key question for stakeholders. To answer this question, the residual collapse capacity of mainshock-damaged buildings should be evaluated, and in this way, an accurate assessment of the structural damage inflicted during a mainshock-aftershock sequence is of great importance. Recent studies have shown that energy-based damage measures, which calculate the dissipated energy due to cyclic-plastic deformations, can more accurately reflect the secondary damage induced by aftershocks than deformation-based damage measures. Park-Ang damage index is a combined seismic damage measure that integrates the damage caused by excessive deformations with the damage caused by the cumulative hysteretic energy dissipation. This study presents a framework for assessing the post-mainshock structural safety, in which the quantification of the damage accumulated during a mainshock and the determination of the remaining capacity to sustain strong aftershocks are made based on the Park-Ang damage index. First, residual collapse capacity diagrams are produced by performing incremental dynamic analysis under a suite of selected sequential ground motions. Next, an average diagram is made to find the maximum safe damage index, so that values above this threshold would represent the buildings that are deemed to be unsafe. The proposed framework is applied to a reference four-story steel moment-frame building to investigate its collapse potential and evaluates its structural safety in a hypothetical earthquake scenario. The results of the case study indicate that the proposed framework can effectively help structural engineers to decide on whether a mainshock-damaged building is safe to reoccupy and communicate the final decision in a simple diagram to stakeholders.

地震事件发生后，就是否受到大地震破坏的建筑物能否承受即将来临的强烈余震而言，持续居住的安全性是利益相关者的关键问题。为了回答这个问题，应评估受到主震破坏的建筑物的剩余倒塌能力，以这种方式，对在主震-余震序列中造成的结构破坏的准确评估非常重要。最近的研究表明，基于能量的损伤度量方法（比起基于变形的损伤度量方法）可以更精确地反映余震引起的二次损伤，该措施可以计算出由于循环塑性变形而产生的耗散能量。Park-Ang破坏指数是一种组合的地震破坏指标，将过度变形引起的破坏与累积滞后能量耗散造成的破坏整合在一起。这项研究提出了一个评估震后结构安全性的框架，其中基于Park-Ang破坏指数对主震过程中积累的破坏进行量化，并确定维持强余震的剩余能力。首先，通过在一系列选定的连续地面运动下进行增量动力分析，产生残余倒塌能力图。接下来，绘制平均图以找到最大安全破坏指数，以便高于此阈值的值将代表被认为是不安全的建筑物。拟议的框架被应用于参考的四层钢框架结构中，以研究其倒塌的可能性，并在假设的地震情况下评估其结构安全性。案例研究的结果表明，所提出的框架可以有效地帮助结构工程师确定遭受重大地震破坏的建筑物是否可以安全地重新占用，并以简单的图表将最终决定传达给利益相关者。