Resilience of critical infrastructure for multiple hazards: case study on a highway bridge

The exposure of critical infrastructure to natural hazards was proven to have severe consequences on world economies and societies. Therefore, resilience assessment of an infrastructure asset to extreme events and sequences of diverse hazards is of paramount importance for maintaining their functionality. However, the resilience assessment commonly assumes single hazards and one restoration strategy. In addition, owners and operators have different approaches for restoring their assets, depending on different factors, such as the available resources and their priorities, the importance of the asset and the level of damage. Yet, currently no integrated framework that accounts for the different strategies of restoration, and hence quantification of resilience in that respect exists. This paper proposes an integrated framework for the quantitative risk and resilience assessment of critical infrastructure, subjected to multiple natural hazards, considering the factors that reflect redundancy and resourcefulness in infrastructure, i.e., (i) the robustness to hazard actions, based on realistic fragility curves, and (ii) the rapidity of the recovery after the occurrence of damages, based on realistic restoration functions. Lastly, the paper includes an application of the proposed framework for a typical highway bridge for realistic multiple hazard scenarios and restoration strategies using a wellinformed resilience index.