Optimizing infrastructure resilience under budgetary constraint

•A new formulation to maximize system resilience under budgetary constraint.•An introduction of utility function into component enhancement.•Introduced a resilience-based component importance. Communities located in regions prone to natural and man-made disasters endure hardship and financial loss in the face of these events. Investment to enhance infrastructure resilience is vital to reduce the consequences of these low probability high-impact events. Budget and resources are limited, and they must be allocated wisely to infrastructure components to build a resilient community. The complexity of infrastructure makes it difficult to show the effects of component enhancements on system resilience. This paper proposes a mathematical programming model aimed at optimizing infrastructure resilience against a set of adverse events by optimally allocating budget to the infrastructure components. Investment, component enhancement, and corresponding functionality are combined with the resilience-based component importance to tackle the system complexity. Three utility functions are presented to determine the possible component enhancement alternatives for an allocated budget and to choose the optimal alternative. A resilience-based component importance metric is introduced, which is used in the budget allocation optimization problem. This approach establishes a relationship between amount allocated to a component and changes in its absorption and recovery, and the aggregate of all such changes on the components on the system functionality. The results show that the utility function of a component impacts the resilience enhancement of the system.