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This paper proposes an approach for developing optimal risk-based management strategies for bridges in coastal regions. Currently, bridge management strategies in these regions are designed to limit the negative effects corrosion has on bridge performance under traffic loads. However, recent large-scale hurricanes and their associated damage to bridges have demonstrated the need to consider hurricanes when making bridge management decisions. This paper aims to develop optimal risk-based management strategies that include both repair actions to address deteriorating performance under traffic loads and retrofit actions to minimize the potential for failure during hurricanes. The proposed approach considers the uncertainties associated with hazards, and the economic, social, and environmental consequences of failure under traffic loads and hurricanes. The optimal management strategies are achieved by formulating and solving a multiobjective optimization problem. The objectives of this optimization problem include minimizing the lifecycle costs accrued due to repair and retrofit actions and minimizing the maximum risk over the lifecycle of the bridge. The proposed risk-based approach is applied to a steel girder bridge located in a hurricane-prone region. [ABSTRACT FROM AUTHOR]

Fatigue is one of the main deteriorating mechanisms that affect the safety and reliability of ship structures. Fatigue cracks can appear at various locations along the ship structure and may occur at early stages in the service life of a ship. Inspection, monitoring and/or repair actions are applied to prevent sudden failures of damaged structural components and their associated consequences. However, these actions increase the operational cost of the ship and should be optimally planned during its service life. Due to the presence of significant uncertainties associated with crack initiation and propagation, the planning of such actions should be performed probabilistically. In this paper, a probabilistic approach for inspection, monitoring, and maintenance optimization for ship details under fatigue effects is proposed. Based on the stress profile and the crack geometry at the damaged location, intervention times and types are determined by solving an optimization problem which simultaneously minimizes the life-cycle cost, maximizes the expected service life, and minimizes the expected maintenance delay over the life-cycle. The life-cycle cost includes the cost of inspection, monitoring, and maintenance actions, as well as the cost of failure of the detail. The proposed approach is applied to a side shell detail of a steel ship. [ABSTRACT FROM AUTHOR]