GPR – Mapping Roadway Voids at DFW Airport

Heavy vehicle use coupled with harsh weather conditions lead to deteriorating highway infrastructure at a major international airport in the South-Central United States.  Analyzing the extent of the deterioration required non-invasive shallow subsurface imaging to be conducted.  The scope of the project was to determine the extent and location of void features and deterioration in the road deck.  THG was contracted to scan 76 sections of road deck to identify void features and assess the conditions of the shallow subsurface.

To image the road deck THG designed a high-resolution ground penetrating radar (GPR) survey.  A Sensors and Software Noggin GPR equipped with a 1000 MHz antenna integrated with GPS was configured to image to a depth of approximately four feet.  Grids were collected using parallel lines with 1-foot spacing. The data was post-processed to result in 3-dimensional blocks for each road section.  Utilizing the depth-slice view, the location, geometry, and size of void features were calculated, despite the presence of dense rebar. These data ultimately guided engineers as they designed and developed a repair and maintenance plan.