| The urban hospital system(UHS)includes hospitals and a medical transportation network.Resilience assessments of UHS under earthquake or multi-hazard conditions are extremely important for post-disaster repair and reconstruction of the city.This paper proposes a new resilience assessment method and calculation framework for UHS under multi-hazard conditions,i.e.,earthquake and corrosion,earthquake-induced landslide,and main aftershocks hazards,that considers the logical dependencies or coupling between hospitals and the medical transportation network,the distribution of the casualties and the path reselection,damage simulation using refined finite element model and functional recovery of post-hazards UHS.The main research results are summarized as follows:(1)A seismic resilience assessment framework is proposed for UHS that considers the logical dependencies or coupling between hospitals and the medical transportation network.The damages of the bridge’s and hospital’s structural and non-structural components are quantified by using the refined nonlinear finite element analysis for real hospital and bridge cases,and then their damage probability and residual functionality are calculated.A simplified calculation method is proposed to quickly obtain the fragility models of regular girder bridges under earthquakes.A resilience index is defined as the ratio between the average‘shortest’ time for a casualty to receive medical treatment after an earthquake and before the earthquake.A real-time simulation model is proposed that considers the casualty sources,the changes in road traffic,the updates of the Origin-Destination(OD)matrix for transportation time,the modifications of waiting time in hospital,the path reselection by casualty,and the changes in functionalities of bridges,hospitals,and roads.A benchmark model of Xiamen’s real UHS seismic resilience assessment is established,including urban geographic information,population information,site conditions,hospital building information,highway bridge information,etc.The proposed method is demonstrated in a seismic resilience assessment of a realistic UHS in Xiamen city of China and provides valuable references to assessments of seismic resilience of UHS.(2)A resilience assessment framework for bridges and roads has been established under multi-hazard conditions,i.e.,earthquake and corrosion,earthquake-induced landslide.Finite element(FE)models of bridge columns with different failure modes(flexure,flexure-shear,shear failures)are established,and the accuracy of the FE model is verified by a comparison with experimental data.The seismic resilience assessment of a real bridge case in corrosive environments is performed by considering corrosion-induced changes in failure modes of bridge columns,and studying the effects of multi-hazard(i.e.,corrosion and earthquake)on the bridge’s damage probability,residual functionality,and resilience indicator.In addition,the resilience assessment of medical transportation networks is performed under earthquake and earthquake-induced landslide hazards,which studies increased damage to the bridge under the action of earthquakes and landslides,and considers the impact of road closures caused by landslides on the resilience of medical transportation networks.(3)A resilience assessment method is proposed for UHS under themain and aftershocks.Based on the benchmark model of real UHS,resilience assessment is performed for UHS under multi-hazard.According to site information and seismic fortification,the mains aftershocks sequences are selected from the Pacific Earthquake Engineering Research Center(PEER)ground motion database.The refined nonlinear finite element analysis is used for quantifying the damage,residual functionality,and resilience indictors of bridges and hospitals under the main aftershocks hazards.The effects of main aftershocks on the damage probability and residual function of hospitals and bridges are studied.Obtained bridge and hospital functionalities are applied to a resilience assessment framework for studying the impact of the main aftershock hazard on the resilience of UHS. |
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