GPR or Ground Penetrating Radar technology is used in many industries to see through natural and man-made materials. This technology is used to locate non-metallic and metallic pipes, conduit, power lines, post-tension and re-bar cables inside concrete, and water lines. Surveyors often make use of GPR prior to renovations or construction within concrete structures or buildings.

Making use of GPR over other methods have several benefits including:

● No health hazards

● Quiet, self-contained operation

● Can detect non-metallic materials

● Provides in-depth estimates

● Instant results

● Can detect and see pipes below the floor

● Can see through up to two feet of concrete

● Provides a permanent record

● Colour map visuals available in different depth slices

GPR services are used by the automotive industry, airports, government, commercial construction, military, manufacturing industries, ports, municipal infrastructure, refineries, power plants and water treatment plants.

Method of GPR

When GPR technology is used, pulses of radio waves are sent to a material from a transmitter. These radio waves are generally employed at a frequency between one and thousand MHZ. Echoes or reflections of this energy are deflected from objects within the material and sent back to the antenna or the receiving device. The device measures the returning signal’s strength and also the travel time. When the pulse that was transmitted comes in contact with a material differing in dielectric permittivity or electrical conductivity a signal reflection is observed. The contrast of the 2 differing materials help to determine the amplitude or strength of the returning signal. Then, a map is created of the features like, buried structures and utilities beneath the ground or reinforcing conduits and bars within the concrete.

The distance the signal travels into a scanned material depends on the material and the device the signal is transmitted through. For instance, glass, plastics and other such highly dielectric materials will slow the signals whilst highly conductive materials will quickly attenuate the signal. Metals are going to let the signal pass through, totally reflecting it back to the antenna. In case of a scan into a concrete or soil profile where a sheet of metal is located beneath the surface, the signal is going to only penetrate to the distance where the metal is located. If there is anything beneath the metal, it will be invisible to the device.

Applications of GPR

GPR technology can be used in several applications, such as analysing concrete structures for reinforcing bars, embedded conduits before cutting for renovations or repairs, and post-tension cables. As already mentioned, GPR is used widely in locating buried utilities like, pipelines, cables, plastic objects and concrete structures beneath the ground and also within concrete.

You can also use GPR for the following:

● Assessing bridge and road structures

● Detecting concrete homogeneity and voids, slab-on-grade assessment

● Measuring the thickness of ice, which is crucial in areas where ice roads are present for part of the year

● Detecting natural and environmental structures like, soil structures, sinkholes, water tables, ground water channels, salt water infiltration and so on

● Detecting underground septic systems, storage tanks, contaminant delineation and also assisting in remediation efforts

When compared to other technologies and methods, GPR needs significant more training and knowledge. A trained and experienced operator of GPR will be capable of determining the position and depth of utility lines. After their detection, they will be marked on the surface prior to beginning any construction or excavation project. This information is also incorporated into a 3D map. The effectiveness of GPR is determined from the operator’s skill and expertise.

So, it is important that you seek a professional company providing GPR training. In order to operate GPR and make sure that you are using it correctly, you need proper training. A training provider will teach you everything you need to know about this technology and that will make sure that your surveys are always a success. You will find a number of training providers in the UK where you can be certified.