Ground Penetrating Radar (GPR)

Ground penetrating radar (GPR) uses a pulsed electromagnetic signal transmitted to and reflected by a “target” (re-bar, wire, moisture, layer interface, etc.,) back to the point of transmission.  The GPR wave transmission, signal velocity, and reflection are dependent on the electrical properties (dielectric constant and conductivity) of the material(s) being investigated. Material changes, such as asphalt to concrete, have sufficient difference in electrical properties to reflect Ground Penetrating Radar or GPR signals. And metal reinforcing and conduits are highly conductive and produce high amplitude (strong) reflectors of GPR signals. GPR results are qualitative and typically a depth determination is based on a site calibration.  


  • Post Tensioning Duct Void Detection
    Jamestown-Verrazzano Bridge
    Narragansett Bay, RI
  • Locating Post Tensioning Ducts
    US 54 Kellogg Bridge
    Wichita, KS
  • Void Size Between Wood Liner & Bedrock
    Edwards/Sunset Tunnel
    Portland, OR
  • Sinkhole Detection
    Pennsylvania Turnpike Rest Area
  • Locate Electrical Conduits
    Terminal B Logan Airport
    Boston, MA
  • Detection of Soil Settlement
    Lake Louise Marie Dam
    New York
  • Foundation Type & Depth
    Cell Tower
    James City, VA
  • Detection of Voids in Concrete Liner
    Underground Water Tank

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NDT Corporation
Massachusetts Office      Florida Office
153 Clinton Road               8413 Laurel Fair Circle, Ste 200-B
Sterling, MA 01564            Tampa, FL 33610

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