The aim of the study is to gather information on three topics: (1) the evaluation and rating of steel bridge protective coatings, (2) coating systems used by various states throughout the United States, and (3) maintenance painting procedures employed by various state department of transportation agencies (DOTs). First, it was found that most state DOTs use either an Element Level type rating of the coating system or a 9–0 NBI type rating; many state DOTs use both methodologies, with one used for state bridges and the other for local bridges. Second, for coating systems, it was found that there is a great deal of uniformity of the steel bridge coating systems used in the United States, with three-coat paint systems being the most common. Third, it is believed that maintenance painting can extend the useful life of bridge coatings. However, many state DOTs report that the cost of maintenance painting has increased due to many factors that involve available personnel, proper training, and increased regulations on the removal and application of steel bridge coatings. Consequently, many DOTs no longer perform maintenance painting, other than emergency repairs, and simply wait until the entire bridge needs to be re-coated and contract the work out. Lastly, an NBI 9–0 type rating procedure for steel bridge coatings is proposed for possible consideration and implementation by INDOT.

Report Number



coatings, paint, steel bridge, evaluation, rating, maintenance painting

SPR Number


Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, IN

Date of this Version