Statewide bridge deck survey using Ground Penetrating Radar

The Arizona Department of Transportation (ADOT) implemented a statewide bridge deck Ground Penetrating Radar (GPR) survey of 134 bridges. The deck component of this inspection was carried out using GPR, coupled with coring, half-cell corrosion potential tests, and chloride sampling. The GPR survey provided the first round of data, producing maps for each deck showing potential areas of concrete deterioration and depth of reinforcement. These maps were been used by field inspection crews to locate the subsequent tests, and to determine sample depths for chloride testing. The GPR field data was collected at normal driving speed without lane closures or interference to traffic. The total data collection effort for the 134 bridge decks, including mobilization throughout the state, consumed 35 field days. Data analysis was carried out at a rate of up to 15 bridges per week, so that the GPR maps were available for the field crews in re for their work. The project provided ADOT with 100% coverage data on deck condition and depth of rebar on over 1.5 million square feet of bridge, at considerably less cost than alternative methods.