Seismic risk assessment of bridge networks with insufficient resilience considering functionality uncertainty due to performance damage

Risk-oriented performance-based seismic engineering has emerged as a mainstream direction in seismic research. As a crucial component of risk, resilience indicators have garnered increasing attention in recent years. The resilience indicators of networks exhibit significant randomness due to the varying functional losses and recovery processes resulting from the performance degradation of bridge network components. This results in the post-earthquake functionality of transportation systems failing to meet basic functionality standards, indicating insufficient resilience and ultimately leading to increased seismic risk. This paper presents a method to analyze the seismic risk from insufficient resilience of the bridge networks. The seismic risk of insufficient resilience arises from seismic hazard and the conditional probability that the networks fail to meet a basic functional level within a certain recovery time after the seismic event. The proposed method first establishes bridge topology networks with transportation functionality connections and assesses the post-earthquake functional status of the bridge networks based on the seismic performance of bridge structures. The insufficient resilience risk due to functionality uncertainties under recovery strategies was evaluated using the network operational functionality in the emergency, transition, and reconstruction phases as resilience indicators. Further, the risk-related weight is utilized to evaluate relative importance of individual bridges.