Ground Penetrating Radar - Get a clear picture from underground

It’s fair to say that Ground Penetrating Radar (GPR) sings a song unheard by the majority involved in UK utilities, civil engineering and archaeological industries.  A steadily growing European demand has led to technological advances in GPR producing a new wave of advanced, compact, and easy to use systems. 

Riding at the forefront of this growing market are Geoscanners AB (GAB), a leading GPR equipment manufacturer hailing from northern Sweden.  GAB in partnership with their sole UK distributor, Phoenix Survey & Safety (PSS) recently put one such model to good use in Weymouth, a southern town besieged by contractors preparing the area for the upcoming Olympics.

PSS Safety Product Manager Adam Baker is charged with spearheading the GPR campaign across the country, Adam was joined at an on-site demonstration by GAB CEO Reinaldo Alvarez Cabrera on one of his regular visits to the UK.

With a typically hands on approach, Reinaldo begins: "Once on-site it became clear that most present didn't have much previous exposure to GPR technology.  This led to a short introduction at a local warehouse demonstrating how to find and correctly identify a utility. The short survey went very well and soon enough we were able to find a pipe at approximately 350mm depth crossing one of the gravel roads in the storage yard. This was clear evidence of the suitability of GPR for this kind of job and within a few minutes we were on our way to the real construction site where the actual survey would take place.

Due to safety regulations we were requested to wear protective shoes, reflective vests, gloves and a helmet which was a little bit strange considering that the survey site was on a public street with many people walking around totally unprotected, of course in this industry it is of the upmost importance to follow health and safety regulations to the letter.

Once on site, a survey of a bridge over a small river was conducted to confirm whether or not it contained reinforcing bars and if they had any weaknesses.  The re-bar mesh on the bridge was easily identified on the resulting profile but it was bent downwards in a strange fashion.  This, of course couldn't be right, after a brief moment the cause of the problem became apparent - the bridge had a slight mound over it so the actual depth to the re-bar mesh was constantly changing while walking with the survey cart over it.

The re-bar mesh did indeed have a couple of weak points, probably due to corrosion of the metal in the mesh or just moisture from the underlying river.  I pointed out to the gathered engineers that the distortion of the visible re-bar mesh could be easily corrected in our post processing software GPRSoft PRO if we had the elevation information.  As the data was not collected using GPS we didn't possess elevation details, so I used my phone GPS to sketch out an elevation profile of the survey area to be able to correct for the distortion of the re-bar mesh later on in the post-processing software. The approximation turned out to be pretty good and I got the profile of the road accounting for the elevation changes and an almost straight re-bar mesh".

This Geophysical Mapping example shows one of the many potential uses for GPR, others include Utility Mapping and Archaeological Investigation.  If you have an upcoming job or application and think GPR may be of use please contact 01454 338985 to arrange a free demonstration.

Phoenix Survey & Safety Equipment
Phoenix sell, hire, repair and provide training on a comprehensive range of site surveying and safety equipment across the UK including Survey GPS, Cable Location, Gas Detection, Drain Inspection, Total Stations, Construction Lasers, and much more.

Geoscanners AB
Based in northern Sweden Geoscanner AB are involved in the manufacture and distribution of ground penetrating radar equipment.
www.geoscanners.com