Infrasense Evaluates 5 Missouri Bridge Decks Using GPR Supplemented with Other Methods

In 2018, Infrasense conducted non-destructive surveys and reported for 5 bridge decks in Missouri. The project provided the client with a comprehensive set of condition results to facilitate a data-driven approach to programming rehab and maintenance efforts.

GPR surveys were performed at normal driving speed with no disruption to traffic. The GPR data collection system included a pair of 2 GHz horn antennas and a SIR 30 control unit, both manufactured by GSSI in the United States. As a supplement to the GPR surveys, chain drag, coring, and infrared thermography were used on select bridge decks. The final report included quantities of deterioration detected by GPR and hollow sounding areas detected by the chain drag surveys. Infrasense provided plan-view maps of these areas.

The GPR bridge deck surveys are carried out according to ASTM D6087-08. The resulting data shows a cross-sectional slice of the bridge deck at various offsets. Each slice includes the top of the deck, top mat of reinforcing steel, and the bottom of the deck. The amplitude of these layers is calculated and then quantities and maps of concrete deterioration and concrete cover are produced. The resulting maps are provided in both PDF and CADD compatible formats.