ABSTRACT
In the design and operation processes of bridges, decision-makers need a comprehensive indicator to reflect impacts of engineering activities on bridge owners and the public. This indicator should consider not only the economic cost to owners but also the life-cycle social impacts. Therefore, a life-cycle cost (LCC) model considering various social costs of bridges is proposed in this paper. The proposed model consists of costs to bridge users, waterway users, and regional businesses. To illustrate this LCC model, pile caps of a coastal bridge is analyzed as an example. For structural deterioration, the combined effect of chloride-induced corrosion and flow-induced erosion is considered. Time-variant reliability analysis is performed to determine life-cycle performance of the investigated pile caps. Maintenance activities are planned based on an annual reliability threshold. The life-cycle direct and social costs associated with the maintenance activities are computed using the proposed LCC model. Compared to life-cycle direct costs to bridge owners, the study shows significant social costs associated with traffic delay and navigation suspension due to life-cycle maintenance activities.
