GPR Applications

Ground Penetrating Radar, otherwise known as GPR, is an indispensable tool in the business of utility locating and mapping. Modern underground locating GPRs are known as cart-type systems because they are mounted on a wheeled frame to be rolled across the ground for ease of use and terrain maneuvering mobility. GPR in the hands of professional utility locators will find utilities made from of all types of materials. For example, conventional radio frequency pipe and cable locating instruments will only detect metal utilities such as electric, telecom and CATV cables, and cast iron/ductile water and gas pipes. This poses a problem for water leak detection technicians trying to pinpoint leaks on plastic and cement water pipes. To be able to find the leak, the technician must first locate the pipe. Only GPR will detect elusive, hard to find, non-metal pipes. GPR is not confined just to underground utility locating, however. Another significant application for GPR cart-type systems is in locating and mapping underground storage tanks (USTs). GPR technology is therefore a huge benefit to the environmental industry for locating abandoned fuel and oil tanks which may otherwise remain undetected and leaking their harmful pollutants into the ground. The GPR antenna frequencies for utility locating and mapping are typically 250MHz and 500MHz and will "see" up to around twenty feet into the ground in ideal soil conditions. In the New York area however, NY utility locators may only reach to depths of up to ten feet due to a high clay content which acts as a barrier to GPR signal penetration. Fortunately for these high-tech utility locators this is not the major problem it appears to be as most utilities are seldom buried at depths greater than four feet.

Another application for GPR is for utility locating and mapping inside concrete slabs and structures. This is sometimes known as concrete x ray. Instead of being mounted on wheels such as cart-type GPR systems are, the concrete x ray GPR instruments are compact, highly portable, handheld units. They are constructed with a flat, hard-wearing, skid underside, and are slid over the concrete structure surface. Concrete x ray GPR antennas are of a very high frequency range and are typically 1GHz, 1.6GHz, 2GHz and 2.6GHz. These Sophisticated GPRs will "see" up to two feet into concrete and are used for utility locating and rebar mapping. Utility locating technicians who operate concrete x ray GPR equipment must be highly trained and experienced as there are inherent dangers in utility locating in concrete structures. Live electric and structural post-tension cables are often hidden inside concrete floor slabs. In older high-rise buildings in New York City especially, where modernization and remodeling takes place on a huge scale, the general contractor who comes along to saw-cut through the concrete walls and floors wants to be sure he will not hit potentially lethal live electric or the post-tension cables which effectively hold the building up. Concrete x ray GPR in the hands of expert NY locators will therefore give contractors that all important assurance and allow him to proceed with confidence.