We present an adaptation of the tri-level Operator-Attacker-Defender (OAD) model for designing resilient supply chains, addressing disruptions such as supplier failures, production shortfalls, and disabled transportation links. These disruptions impact the supply chain's performance regarding its ability to meet customer demand. Originally proposed by Alderson et al. in 2011, the OAD model integrates three levels of decision-making: the operator optimizing system performance, the attacker seeking to disrupt it, and strategic system design decisions to mitigate disruptions. Our conceptual model is based on a multi-commodity flow network with a defined performance metric, formulating the tri-level optimization problem accordingly. Due to its complexity, we employ a decomposition-based solution strategy. Extensive computational experiments demonstrate the model's tractability across various supply chain scenarios. A real-world case study on a global pharmaceutical supply chain illustrates the OAD model's effectiveness against climate-related disruption. With its ability to help explore trade-offs between operational efficiency, costs, and resiliency, this model contributes to Resilient Supply Chain Design (RSCD) by providing a deterministic framework for designing supply chains capable of withstanding disruptions.