Retrofitting critical components of a critical infrastructure system to improve its seismic performance has been considered as the most frequently used mitigation strategy in both literature and practice. This article mainly studies this mitigation strategy and formulates the seismic retrofit optimization problem for critical infrastructure systems under a limited retrofit budget in a general form, and then proposes a heuristic method to solve the problem efficiently in terms of the optimality gap and the computational cost. The proposed method mainly includes three steps: (1) generates a limited number of component damage scenarios to reformulate the problem as an approximated model; (2) adopts a component importance-based method to reduce the solution space and applies the integer L-shaped method to solve the approximated model; (3) employs the sample average approximation method to enhance the solution quality. To demonstrate the performance of the proposed method, it is applied to identify the optimal retrofit strategies for the Shelby power transmission system, the IEEE 14-bus test system, and the IEEE 118-bus test system and also compared with several existing methods. Results show that the proposed method is significantly more efficient than those existing methods. For the IEEE 14-bus test system, the proposed method gets almost exact solutions, with errors less than 0.29%; for the other two systems, it returns the best solutions among all methods under various retrofit budgets.

中文翻译：

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一种确定关键基础设施系统最佳抗震改造策略的启发式方法

改造关键基础设施系统的关键组件以提高其抗震性能已被认为是文献和实践中最常用的缓解策略。本文主要研究了这种缓解策略，并以一般形式制定了有限改造预算下关键基础设施系统的地震改造优化问题，然后提出了一种启发式方法，以从最优差距和计算成本方面有效解决问题。所提出的方法主要包括三个步骤：（1）生成有限数量的组件损坏场景，将问题重新表述为近似模型；(2)采用基于分量重要性的方法缩小解空间，并应用整数L形方法求解近似模型；(3)采用样本平均逼近法提高解的质量。为了证明所提出方法的性能，将其应用于确定 Shelby 输电系统、IEEE 14 总线测试系统和 IEEE 118 总线测试系统的最佳改造策略，并与几种现有方法进行比较。结果表明，所提出的方法明显比现有方法更有效。对于IEEE 14总线测试系统，该方法得到了几乎精确的解，误差小于0.29%；对于其他两个系统，它返回了各种改造预算下所有方法中的最佳解决方案。用于确定谢尔比输电系统、IEEE 14 总线测试系统和 IEEE 118 总线测试系统的最佳改造策略，并与几种现有方法进行比较。结果表明，所提出的方法明显比现有方法更有效。对于IEEE 14总线测试系统，该方法得到了几乎精确的解，误差小于0.29%；对于其他两个系统，它返回了各种改造预算下所有方法中的最佳解决方案。用于确定谢尔比输电系统、IEEE 14 总线测试系统和 IEEE 118 总线测试系统的最佳改造策略，并与几种现有方法进行比较。结果表明，所提出的方法明显比现有方法更有效。对于IEEE 14总线测试系统，该方法得到了几乎精确的解，误差小于0.29%；对于其他两个系统，它返回了各种改造预算下所有方法中的最佳解决方案。误差小于0.29%；对于其他两个系统，它返回了各种改造预算下所有方法中的最佳解决方案。误差小于0.29%；对于其他两个系统，它返回了各种改造预算下所有方法中的最佳解决方案。