Seismic resilience assessment of critical infrastructure-community systems considering looped interdependences

Abstract

To examine the impact of looped interdependences among Critical Infrastructure Systems (CISs) on their seismic resilience, an agent-based modelling (ABM) framework has been proposed in this paper. In such a framework, the coupled Transportation System (TS) and Electric Power Supply System (EPSS) have been included. The functionality losses of both TS and EPSS following seismic hazards were quantified by vulnerability functions. Meanwhile, their functionality trajectory during the corresponding post-shock recovery phase were tracked by the developed ABM. Two agents, namely, the two Operators running recovery campaign of TS and EPSS, respectively, are considered. Particularly, the restoration of EPSS is set to be contingent upon the functionality of TS, in the sense that EPSS components can be repairable, only if accessible via the TS. In turn, the restoration of TS will also be influenced by the functionality of EPSS, as many restoration equipment of TS need the power to function. To demonstrate its applicability, such a framework was applied on a virtual network comprising a TS, an EPSS and the urban community that they serve, given different interdependence degrees between the two CISs. A parametric analysis was run to study how the post-shock recovery of the two CISs would be molded by the interdependence between them, under different earthquake scenarios. The simulation outcome demonstrates that the developed framework is able to delineate the post-shock recovery of the coupled TS-EPSS-Community, whose resilience will be sharply weakened, as the interdependence degree reaches a particular threshold value, when it comes to strong shocks.