Optimizing Bridge Network Retrofit Planning Based on Cost-Benefit Evaluation and Multi-Attribute Utility Associated with Sustainability

During their service life, bridge networks may be exposed to extreme events, including strong earthquakes, which pose an imminent threat to society, economy, and surrounding environment. This threat reinforces the need to implement updated sustainability assessment and optimal risk mitigation procedures. The sustainability-based seismic optimization of bridge networks considering the utility associated with cost and benefit of retrofit interventions is investigated. The ultimate aim of this framework is to reduce the extent of earthquake damage to society, economy, and environment, while simultaneously minimizing the total retrofit costs of bridge networks. The total benefit of a retrofit plan is quantified in terms of the reduction in the seismic loss during a given time interval using multi-attribute utility theory. Retrofit actions associated with varying improvement levels are considered herein. A genetic algorithm based optimization procedure is adopted to determine the optimal retrofit action for each bridge within an existing bridge network.