In the past 5 years, Infrasense has used ground penetrating radar (GPR) and infrared thermography (IR) to evaluate the condition of 62 bridge decks in the Greater Chicago area. These bridge decks carry 3 to 4 lanes of traffic along major highways such as I-355, I-294, I-55, and the Elgin O’Hare Expressway, and represent over 750,000 square feet of total area. The GPR surveys were carried out overnight at driving speeds, so no closures were required and traffic flow was not disrupted. The IR surveys were prerformed using a rolling closure to minimize the disruption of traffic flow, and delaminations were confirmed in the field with ultrasonic Impact Echo testing.
The GPR and IR surveys resulted in deterioration quantities and maps for each of the reinforced concrete bridge decks. Additionally, the GPR surveys also produced rebar depth contour maps for each bridge deck. The deck condition information will be utilized to prioritize and plan future maintenance and rehabilitation efforts.
Infrasense completed a ground penetrating radar (GPR) survey to map the size and position of the steel reinforcing mesh within an undocumented pier extension at the Midway Airport in Chicago, Illinois