Photo of area scanned. GPR used to map out reinforcing rebar and electrical conduits.
Ground Penetrating Radar Systems, LLC. – GPRS –
of Southern California was contacted by a local construction company at the
beginning of their project to install a new hoist beam at a location in Oxnard,
CA. The installation of the hoist beam required anchor bolts to be drilled
through the slab and the contractor understood the dangers of drilling into a
concrete slab without understanding where the structural elements are as well
as potential conduits or other utilities. Concrete scanning using ground
penetrating radar can protect the integrity of the structure as well as the
safety of the cutting and coring personnel.
When scanning a concrete slab, clients should
typically be worried about two types of obstructions within the slab. These are
structural elements and utilities that may be have been cast into the slab.
Structural elements include rebar, pre- and post-tensioned cables, and beams.
Depending on the type of slab and conditions of the site, GPR can help a
skilled technician not only identify the location of these items, but also
differentiate the most likely type of structural element. It is important to
remember that this is not information provided by the GPR, rather the data
given by the GPR combined with that technician’s training on the various types
of structural slabs that allows differentiation to happen. While GPRS does have
Project Managers with the ability to perform this differentiation, the most
common scenario encountered by GPRS is one in which the client would like to
avoid all obstructions in the slab. This allows for maximum safety on the
project and saves a lot of effort and time on the core driller’s part by not
having to run the bit through the rebar in the slab.
The scope for the scan included locating rebar
and locating conduits in a 50’ linear section of the ceiling and then another
10 linear feet in the other direction. We scanned approximately 2 feet on both
sides of the centerline and marked all obstructions within the concrete slab.
While ground penetrating radar does not
necessarily show different reactions for conduits vs rebar vs post-tension
cables, GPRS trains their technicians to be able to use pattern information
such as depth, rise and fall, and orientation of a target in a slab to be able
to identify the likely identification for each target when this information is
critical to the project. For this particular project, all possible conduits
were marked and labeled with red while possible rebar was marked in blue. All
anomalies were marked in real time and the total amount of time spent on this
project was 1 hour.
GPR scanning is a great tool to use for post
tension cables, rebar, and conduits; it can also be used to scan for
underground utilities prior to digging or excavating. GPRS has offices
throughout the entire state of California and performs projects in cities like;
Ventura, Santa Barbara, Thousand Oaks, San Luis Obispo, Bakersfield, Lancaster
and the greater Los Angeles area. Please contact Alfredo Espinal at
805-729-5877 or firstname.lastname@example.org to learn more about ground
penetrating radar and how GPRS can assist in your projects.