COMPARATIVE-ANALYSIS OF BRIDGE SUPERSTRUCTURE DETERIORATION

This paper presents the results of a study of rates of deterioration o f steel and prestressed concrete bridge superstructures. The study inv olved forming sample groups of bridges that were homogeneous in terms of characteristics, other than superstructure material, which were exp ected to influence rates of deterioration. Superstructure condition ra ting was regressed against age and average daily traffic for sample gr oups of homogeneous steel and prestressed concrete bridges in the nati on as a whole, as well as in seven states selected to represent divers e terrains and environments. Results indicated that age is the primary determinant of superstructure deterioration, followed by average dail y traffic. Choice of structural material does not significantly affect superstructure deterioration rates. The study also found that deterio ration of bridge superstructures takes the form of a convex function o ver time, with the rate of observed deterioration slowing as a bridge ages.