Probabilistic assessment of an interdependent healthcare–bridge network system under seismic hazard

Strong earthquakes can destroy infrastructure systems and cause injuries and/or fatalities. Therefore, it is important to investigate seismic performance of interdependent infrastructure systems and guarantee their abilities to cope with earthquakes. This paper presents an integrated probabilistic framework for the healthcare–bridge network system performance analysis considering spatial seismic hazard, vulnerability of bridges and links in the network, and damage condition of a hospital at component and system levels. The system level performance is evaluated considering travel and waiting time based on the damage conditions of the components. The effects of correlation among the seismic intensities at different locations are investigated. Additionally, the correlations associated with damage of the investigated structures are also incorporated within the probabilistic assessment process. The conditional seismic performance of the hospital given the damage conditions of the bridge network and the effect of bridge retrofit actions are also investigated. The approach is illustrated on a healthcare system located near a bridge network in Alameda, California.