A multi-objective approach for the management of aging critical highway bridges

This paper presents an approach for a multi-objective-based management of aging critical highway bridges to improve their life cycle performance with emphasis on improving public safety and security. The proposed multi-objective optimization framework is presented as an effective approach that overcomes some of the limitations and complexities of cost-benefit or risk analyses, where all consequences need to be expressed in monetary terms. The framework prioritizes first the critical bridges and then identifies the risk mitigation measures that can be used to satisfy several possible management objectives such as maximizing public safety and public security, minimizing traffic disruption and minimizing costs. Risk mitigation strategies can include more frequent and/or more in-depth inspections, load rating, monitoring of the structural performance and security of bridges, rehabilitation and strengthening of damaged elements, and protection of weak and vulnerable components against extreme shocks due to natural hazards or intentional attacks. A multi-objective criticality index is proposed as a prioritization criterion that achieves an adequate best trade-off between all identified and conflicting objectives. The implementation of the proposed approach is demonstrated on three examples that illustrate the prioritization process on a hypothetical network of ten critical bridges and the use of different risk mitigation measures, such as health monitoring and deterioration prediction models on bridge structures.
Aging Infrastructures Workshop: 21 July 2009, Columbia University, New York City