Resilience-based post-disaster recovery strategies for road-bridge networks

Abstract

This paper presents a novel resilience-based framework to optimise the scheduling of the post-disaster recovery actions for road-bridge transportation networks. The methodology systematically incorporates network topology, redundancy, traffic flow, damage level and available resources into the stochastic processes of network post-hazard recovery strategy optimisation. Two metrics are proposed for measuring rapidity and efficiency of the network recovery: total recovery time (TRT) and the skew of the recovery trajectory (SRT). The TRT is the time required for the network to be restored to its pre-hazard functionality level, while the SRT is a metric defined for the first time in this study to capture the characteristics of the recovery trajectory that relates to the efficiency of those restoration strategies considered. Based on this two-dimensional metric, a restoration scheduling method is proposed for optimal post-disaster recovery planning for bridge-road transportation networks. To illustrate the proposed methodology, a genetic algorithm is used to solve the restoration schedule optimisation problem for a hypothetical bridge network with 30 nodes and 37 bridges subjected to a scenario seismic event. A sensitivity study using this network illustrates the impact of the resourcefulness of a community and its time-dependent commitment of resources on the network recovery time and trajectory.

Keywords:

• Decision optimisation
• network recovery
• resilience
• restoration schedule
• transportation networks
• uncertainty modelling

Acknowledgements

Any opinions, findings and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect NIST.

Notes

1. In the WIPW formulation, a link is a segment that can only have one bridge at most, because the mitigation decision is made on individual bridges (links), each of which needs a unique identity in the network topology representation.

2. A pathway between a node-pair usually consists of multiple arcs connected in series. Independent pathways (IPW) are defined as the pathways between a node-pair that do not share any common arcs (road segments). Dijkstra’s algorithm (Skiena, 1990) can be used to search for IPWs between any node pairs.