Modeling Interaction of Emergency Inspection Routing and Restoration Scheduling for Postdisaster Resilience of Highway-Bridge Networks

Postdisaster emergency restoration of damaged highway-bridge networks are crucial to those providing timely emergency assistance to disaster-damaged areas. Ideally, inspection routing and restoration scheduling should complement each other, such that multiple inspection and restoration crews can operate simultaneously and optimally in the immediate aftermath of disaster events. Therefore, it is necessary to understand the interaction between inspection and restoration in postdisaster emergency restoration processes of highway-bridge networks, as well as their impacts on the inspection routing, restoration scheduling, and overall process. This paper proposes an integer program for modeling such inspection-routing and restoration-scheduling problems, accounting for the inspection-restoration interactions, for determining the optimal inspection routes and restoration schedules for damaged highway-bridge networks, with the specific aim of maximizing the networks' travel time as their resilience metric. A hybrid genetic algorithm coupled with an early termination test is also developed to improve the proposed integer program's computational efficiency. The results of a case study using the proposed method and data from China's 2008 Wenchuan earthquake show that, as compared to a traditional sequential inspection-restoration model, simultaneously and optimally performing inspection and restoration can significantly improve highway-bridge-network resilience.