Life-Cycle Seismic Resilience of Bridges and Infrastructure Networks

摘要

Resilience has gained a prominent importance in design, assessment, maintenance, and management of structures and infrastructure systems exposed to extreme events, such as earthquakes. In particular, the resilience of bridges and road infrastructure networks is crucial in the emergency response to seismic events to avoid outages and disruptions of critical facilities and ensure both a quick deployment of aids and resources to distressed communities and a prompt repair of lifelines and buildings. However, seismic resilience is affected over time by aging and deterioration processes of materials and structures. In fact, the detrimental effects of environmental aggressiveness can modify the seismic performance and functionality and, consequently, make the system resilience depending on the time of occurrence of the seismic event [1]. This lecture presents a probabilistic framework for life-cycle seismic assessment of deteriorating bridges and resilience analysis of road infrastructure networks considering the interaction of seismic and environmental hazards [2, 3]. The time-variant seismic fragilities associated with limit states are computed for single bridges and traffic analysis is carried out at both component and network levels to assess the time-variant system functionality and seismic resilience of the road network. This approach is applied to reinforced concrete bridges and highway networks with detours and re-entry links. Bridges are exposed to chloride-induced corrosion and earthquake scenarios with different magnitude and epicenter location and the road infrastructure is upgraded over time with additional network branches. The results show that the network functionality is substantially reduced by seismic damage, particularly when important traffic restrictions are applied and traffic flow cannot be detoured. The functionality drop and its impact on the post-event recovery process and time-variant resilience are exacerbated by the combined effects of seismic damage and structural deterioration. Consequently, risk mitigation strategies may require repair interventions and network upgrades. This indicates the importance of a multi-hazard life-cycle-oriented approach to seismic design of resilient structures and infrastructure systems.