Forty-eight bridge decks were investigated for deterioration using visual, mechanical, electrical and chemical techniques. Data from the various techniques and the techniques themselves were compared and evaluated, resulting in a data base for Washington's bridges and recommendations for efficient condition determinations.
Of the thirty-seven bridges for which all four types of inspection could be accomplished, twenty-nine were deteriorating as evidenced by delaminated concrete, and only two had non-deteriorating scores for all four techniques.
None of the investigative techniques used in the project have been shown able to predict deck deterioration problems six to eight years in advance, our desired time period for project planning.
The mechanical technique, commonly referred to as the "chain drag", is the method recommended for continued use by bridge inspection crews.