The Douglas Company was in the midst of a complete apartment building renovation with plans to saw cut the concrete to install all new plumbing lines for the kitchen area.  They, fortunately, discovered prior to the saw cutting process that the concrete was reinforced with Post Tension Cables.  This was a concrete slab on grade application and therefore The Douglas Co. did not anticipate that there would be post tension cables in the concrete.  They realized that hitting these cables with a saw could cause costly damage to the structure of the building and needed to quickly find a way to accurately and effectively locate them.  They contacted Ground Penetrating Radar Systems to see if they could help them.  Ground penetrating radar is a technology uniquely setup to locate reinforcing steel in slab on grade situations.  The technology is frequently used to locate rebar, wire mesh, electrical conduits and other utilities running in and under concrete slab on grade applications.  Recently, with the increase in popularity of post tension cables, GPRS has been using the technology to locate the cables as well.

GPRS mobilized to the site and mapped a 40’x40’ area in about 2 hours on site.  GPRS discovered that the cables were placed on 3-4 ft. centers throughout the building.  Not only did GPRS locate the cables but they also found the main sanitary sewer line running under the building.  This saved the plumbing contractor time and money by keeping him from digging and searching for the pipe.  Everything was mapped on the surface with spray paint (see picture below) so they contractors could cut the slab without concern.  Overall, the project was a success.  Below you will see pictures of Chris using a 1500/1600 MHz antenna to perform the surveying.  You will notice the yellow painted lines on the concrete indicating the PTC.  You may also notice a green painted line indicating the sanitary sewer line.  If you are interested in obtaining more information or a quote please visit out "Contact Us” page for a local representative near you.