Time-Variant Risk Assessment of Bridges with Partially and Fully Closed Lanes due to Traffic Loading and Scour

摘要

This article presents an approach for assessing time-variant risk associated with the closure of bridge lanes due to traffic loading and scour. Scenarios of lane closure are identified for both traffic loading and scour. The time-variant failure probabilities of girders under traffic loading are evaluated using a deterioration model that accounts for the decrease in resistance and a live-load model that considers the increase in maximum load effects. The annual failure probabilities of pier columns due to scour are estimated by comparing pier depth and scour depth caused by the annual peak flow. The probabilities of occurrence of the identified closure scenarios are computed on the basis of the relations between these scenarios and the failure events of girders and pier columns, and the correlations among failure modes are considered. The consequences caused by the lane-closure scenarios are evaluated by considering repair, running, and time-loss costs. Finally, the time-variant risks associated with the identified scenarios are assessed. The proposed approach is illustrated using a highway bridge as an example. (C) 2016 American Society of Civil Engineers.