Structure Scan | Rebar Maping | Voids In Masonry
Ground Penetrating Radar
Ground-penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation in the microwave band (UHF/VHF frequencies) of the radio spectrum, and detects the reflected signals from subsurface structures. GPR data are acquired by transmitting pulses of radar energy into the ground from a surface antenna, reflecting the energy off buried objects, features, or bedding contacts and then detecting the reflected waves back at the ground surface with a receiving antenna.
Applications of GPR include locating buried voids/cavities, underground storage tanks, sewers, buried foundations, ancient landfills. It can also be used to characterize bedrock, ice, the internal structure of floors/walls, water damage in concrete, and the internal steelwork in concrete.
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GPR uses transmitting and receiving antennae. The transmitting antenna radiates short pulses of the high-frequency (usually polarized) radio waves into the ground. When the wave hits a buried object or a boundary with different dielectric constants, the receiving antenna records variations in the reflected return signal. The greater the contrast in electrical (and to some extent magnetic) properties between two materials at an interface, the stronger the reflected signal, and therefore greater the amplitude of reflected waves. When travel times of energy pulses are measured, and their velocity through the ground is known, distance (or depth in the ground) can be accurately measured.
The depth range of GPR is limited by the electrical conductivity of the ground, and the transmitting frequency. Higher frequencies do not penetrate as far as lower frequencies, but give better resolution. Optimal depth penetration is achieved in dry sandy soils or massive dry materials such as granite, limestone, and concrete. In moist and/or clay laden soils and soils with high electrical conductivity, penetration is sometimes only a few inches.
Applications:
Concrete Slab Imaging (Structure Scan)
- Floor, ceiling and wall inspection
- Locate rebar, tension cables, and conduits
- Estimate cover and spacing of rebar
- Estimate wall and slab thickness
- Identify the size of footing
- Ungrouted vs. grouted concrete masonry unit cells
Utility Locating and Mapping (Utility Scan)
- Locate metallic and non-metallic targets
- Locate buried service utilities like gas, electric and sewer lines
- Estimate depth and location of objects like water mains, underground storage tanks, terra cotta pipes and voids
- Geological investigation
Subsurface void and cavity Mapping
- Determine position and size of sink holes
- Detect voids in structures
Geological & Mining Applications
- Deep bedrocks profiling
- Karst mapping
- Fractures characterization
- River & lake bottom profiling
- Soil & aggregate mapping
- Groundwater resources
Environmental Application
- Groundwater resources
- Site assessment
- Hazardous Waste site assessment
- Landfills delineation
- Underground Storage Tank location
Road Inspection and Evaluation
- Determine pavement layer thickness
- Perform base and sub-base evaluations with data densities
Bridge Deck Assessment
- Determine the condition of aging bridge decks, parking structures, balconies and other concrete structures
- Concrete cover depth
- Measure slab thickness
- Void detection and location
GEM-300 (Electromagnetic Induction tool)
- Ground water investigation
- Geological investigation
- Site assessment
- Chemical Analysis
- Corrosion Testing
- Failure Analysis
- Field Inspection Services
- Ground Penetrating Radar
- Mechanical Testing
- Non Destructive Testing
- Product Testing
- Training
- Welding Engineering
Services, Inc.
1601 Lower Rd
Linden, NJ 07036
Ph: 908-862-4800,
Fax: 908-862-4825
E-mail:
its@inspecttest.com
