The DECAR radar system was evaluated for highway-speed bridge deck condition assessment by the New Hampshire Department of Transportation on three survey networks comprising 44 decks. DECAR (DEck Condition Assessment using Radar) incorporates van-mounted radar equipment, computer-based digital data acquisition equipment operating in the van, a set of procedures for organising and conducting surveys, and software for collecting and processing the data. It was shown in each of the three surveys that groups of bridge decks could be successively surveyed at highway speeds up to 55 mph during a continuous round trip over the survey route. At this speed, production rates of10 to 20 decks per day can be easily expected. Of the 44 decks surveyed, 19 were evaluated during replacement or repair to determine deck condition, and an additional 8 were new decks. The radar deterioration predictions using DECAR were compared with these known conditions, with a correlation (R-squared) of 0.81, and a standard error of plus or minus 4.4 percent of the total deck area. When the radar data were used to classify the decks into one of four categories, the radar results were accurate 93 percent of the time. The DECAR results were shown to be repeatable when repeat surveys were conducted at different times by different personnel. It was concluded that the DECAR system could be effectively and economically used to set up a bridge deck condition data base for bridge management and to monitor deck performance over time. (Author/publisher)
Samenvatting