Deterioration models for life-cycle cost analysis of bridge decks in Nebraska

Deterioration models are vital to life-cycle cost assessments of bridges. Maintenance and user costs depend on bridge conditions, which vary across the period of analysis. The quality of LCC-based decisions depends on the accuracy and efficiency of the deterioration models used to predict the remaining service life of highway bridges. In Nebraska, the national average deterioration rates are used to predict the condition of bridge components. These rates do not represent the actual performance of bridges in Nebraska, however. The Nebraska Department of Roads therefore sponsored a research project to develop deterioration models specific to Nebraska's bridges, which used condition data collected from 1998 to 2010. In this paper, deterministic and stochastic deterioration models for bridge decks in Nebraska are presented. These models reflect the impact of parameters that govern deterioration, which include average daily traffic, average daily truck traffic, wearing surface type, highway district, and deck protection. The deterioration models developed indicated that the deck deterioration rate in Nebraska was lower than the national average and that it depended on traffic volume and highway district. Also, the service life of decks with epoxy-coated reinforcement was longer than that of decks with black reinforcement.