When there’s a need to identify and assess what’s situated under a concrete surface without defacing it, GPR, short for ground penetrating radar is the choice tool for most civil engineers.

Typically, GPR develops an image of the geophysical structure to be assessed by transmitting radio waves into it, waiting for a reflected energy profile before going on to analyze and then derive a contextual picture. It’s an efficient tool for mapping out utilities (especially those of the non-conductive type) in a project area sequel to construction work. More so, when combined with technologies like EM induction, it’s well and truly capable of deriving a complete schema of entire subsurface utility complexes and ratifying available information.

These features along with its portability, real-time reports/analysis, and more importantly relative safety have made GPR hugely popular. With that popularity came a slew of some GPR related facts some of which were true, others, not so much.

Ground penetrating radar facts

  • GPR is as safe as it gets

Unlike conventional means of assaying construction sites that are either grossly invasive (in extension potentially destructive) or based on potentially harmful technologies, underground scanning uses small controlled beams of radio waves, approx. 0.01% that released from everyday mobile phones. The implication of this is that it is safe to operate even with humans nearby and will have no short or long-term effect on the assayed site.

  • GPR is cheaper too!

Overall, GPR underground surveys are pocket-friendly, especially when compared to other means of assaying a site. While conventional scanning techniques require due preparation and site clearance (which further escalates costs), GPR can be conducted with relative ease and without the need for displacing site setups and public utilities.

Some misconceptions

  • GPR uses X-rays

One widespread myth about GPR underground scanning is that it utilizes X-rays to scan and produce an imagery of structures. This presumption is largely because most people expect devices that scan hard structures to be based on X-ray technology. However, this is not always the case and as we’ve already reiterated, GPR uses another form of electromagnetic waves called radio waves. Radio waves are safer to work with, require less energy and overall produce better results

  • Underground scanning machines produce crystal clear images of what’s underneath

What an underground scanning equipment does provide is generalized data about the features located underground. In other words, it can only detect, not identify what structures are buried in the assay site. Determining the structure is the job of an analyst, and this is achieved by using a trained eye to isolate the subtle characterizations of features in the results projected by an underground scanning device.

  • GPR is hydrophobic

On the contrary, underground surveys work perfectly well with water, especially if the water is from a freshwater source. Luckily this is the kind that’s present in most municipalities. However, if the water is from a saltwater source, it has the propensity to interfere with the EM waves used by GPR. This is because salt water houses a myriad of minerals and ions.

So there you have it, a brief rundown of the truths and misconceptions about GPR. We do hope it helps you develop a better understanding of its efficiencies and applications in the engineering sector.

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