Reliability of bridge decks in the United States

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Reliability, service life, survival analysis, bridge decks, deterioration


Deterioration of bridge decks in the United States is an important issue due to its major impact on bridge maintenance costs nationwide. In this paper, results of survival (reliability) analyses performed on bridge data for all fifty states and Puerto Rico are presented. Data were obtained from the 2011 National Bridge Inventory (NBI) database. The end of service life is defined as a recorded NBI bridge deck rating of 5. Only non-reconstructed bridges and conventional bridge types and decks were considered. The NBI-derived parameters included in the analyses were age, average daily traffic (ADT), deck surface area, and deck rating. Each state’s data were analyzed separately to assess and compare relative performance among the states. Deck reliability at an age of fifty years ranges from less than 20% to over 90%. The geographic regions with the highest overall 50-year reliability are generally in the northeastern and northern United States.