GPRS Missouri National Service

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List of Services That We Provide

Ground Penetrating Radar Systems offers services for a wide variety of construction applications.  Our most commonly requested services are listed below.  Production numbers are given for estimating purposes only; please contact us for job-specific quotes.

Underground Applications:

  • Utility Detection
  • Void Investigations
  • UST and Buried Debris Searches
  • Cemetery/Forensics searches. 

Concrete Applications:

Concrete Analysis (elevated concrete slab) - Identifying and marking location of Post-Tensioned Cable, Rebar, electrical conduits, and other miscellaneous anomalies (phone, data, plumbing) in elevated concrete slabs prior to core drilling. Typical production would be 30-45 coring locations (2’x2’) per day. 

  • Equipment performance and accuracy - 1500/1600 MHz antenna – This antenna allows for GPR signal penetration 18”-24” through concrete.  Our depth penetration is greatly determined by the age of the concrete as well as the amount of reinforcing steel present.  Additionally, please expect our accuracy to be +/- ¼” to the center of the steel and +/- ½” to its depth. 
  •  General limitations - A good percentage of our work does deal with assisting in the detection/locating of reinforcing steel (including rebar, post tension cables, and wire mesh) and electrical conduits in elevated concrete slabs.  While the services we provide are professional grade there are often scanning restrictions that could inhibit our accuracy.  These conditions could include but are not limited to moisture present in the concrete, amount of reinforcing steel reflection, depth of target being located, concrete thickness, etc. These restrictions could inhibit the effectiveness of our services.
    • Please note that ground penetrating radar, as a technology, is unable to determine the difference between rebar, post tension cables or electrical conduit in a concrete slab.  Our technicians, however, are trained and often are able to differentiate (based on pattern, spacing, depth and education) between these anomalies and provide informative markings on the surface.

Concrete Analysis (slab-on-grade) - Identifying and marking location of electrical conduits and shallow utilities found in or just below a concrete slab-on-grade.  This service is typically used to ensure objects are not hit during the concrete saw cutting process.   Typical production would be roughly 5,000sqft. per day. 

  • Equipment performance and accuracy - 1500/1600 MHz antenna – Similar to the accuracy/performance statistics noted above this antenna allows for GPR signal penetration 18”-24” through concrete and sub-grade material.  Our depth penetration is greatly determined by the age of the concrete, the amount of reinforcing steel present, and the sub-grade material and condition.  Additionally, please expect our accuracy to be +/- ½” to the center of the conduit or shallow utility being locating and +/-10% to its depth. 
  •  General limitations - A good percentage of our work does deal with assisting in the detection/location of embedded electrical conduit in concrete slab-on-grade as well as locating shallow utilities just below the concrete.  While the services we provide are professional grade there are often scanning restrictions that could inhibit our accuracy.  These conditions could include but are not limited to moisture present in the concrete, amount of reinforcing steel reflection, depth of target being located, concrete thickness, sub-grade material, sub-surface air voids, etc.  These restrictions could inhibit the effectiveness of our services.
    • Please note that ground penetrating radar, as a technology, is unable to identify the type of utility being located below a concrete slab.  Our technicians, however, are trained and often are able to differentiate (based on pattern, depth, surface indications, and education) between these anomalies and provide informative markings on the surface.

Void Detection - Locating voids under concrete slabs (such as warehouse floors), or beneath the surface (indoor and outdoors). Typical production is approximately 20,000 square feet per day for concrete slabs.

  • Equipment performance and accuracy –
    • 1500/1600 MHz antenna – Similar to the accuracy/performance statistics noted above this antenna allows for GPR signal penetration 18”-24” through concrete and sub-grade material.  Our depth penetration is greatly determined by the age of the concrete, the amount of reinforcing steel present, and the sub-grade material and condition.  Additionally, please expect our accuracy to be +/- ½” to the center of the conduit or shallow utility being locating and +/-10% to its depth.
    • 400 MHz antenna – This antenna allows for GPR signal penetration 6’-9’ through the ground pending conducive soil conditions being in the area.  Additionally, please expect our accuracy to be +/6” to the center of the located utility and +/-10% with regards to the depth indication provided.  This antenna is best suited for underground utility locating for most applications.
  • General limitations – In void scanning, the lateral extent of the voids can be determined and marked. The depth to the top of the void can also be detected. However, the depth to the bottom of a void cannot be determined with GPR. Once the signal passes into a void, it will often bounce several times before it is able to work its way back to the antenna on the surface, if it ever does. In this process, all sense of depth within the void is lost. The depth to the bottom of the void can be determined by drilling/probing; this measurement can be used to estimate the volume of the void and the amount of material needed for remediation.

Underground Utility Locating - Locating buried electric, gas, phone, water, or sewer lines. We can typically scan and place surface markers over 1-2 acres (40,000-80,000 square feet) per day depending on site conditions.

  • Equipment performance and accuracy
    • 400 MHz antenna – This antenna allows for GPR signal penetration 6’-9’ through the ground pending conducive soil conditions being in the area.  Additionally, please expect our accuracy to be +/6” to the center of the located utility and +/-10% with regards to the depth indication provided.  This antenna is best suited for underground utility locating for most applications.
    • 270 MHz antenna - This antenna allows for GPR signal penetration 12’-18’ through the ground pending conducive soil conditions being in the area.  Additionally, please expect our accuracy to be +/6” to the center of the located utility and +/-15% with regards to the depth indication provided.  This antenna is best suited for underground utility locating for most applications.
  • General limitations - A good percentage of our work does deal with assisting in the detection of underground utility location, we cannot guarantee we will be able to locate all utilities on site.  GPRS, Inc. provides utility location services in accordance with ASCE Standard 38-02, Quality Level “B” that includes Ground Penetrating Radar (GPR) Services.  GPR is a GREAT tool for utility locating; however, it is not without its limitations.  In general, our maximum depth penetration is 8-10’ deep, however, this depth is completely dependent on the composition of soils in the area being surveyed.  The customer must fully understand that for every foot in depth penetration with the GPR equipment, the pipe/utility must be at least 1” in diameter to be located.  For example, at 4 feet in depth, the pipe/utility must be 4” or larger to be detected.  Some types of pipes are very difficult to locate, such as clay or concrete pipes, and empty pvc type pipes.  Given these factors, GPRS, Inc. CANNOT guarantee we will be able to locate ALL utilities on site. 
    • The material of the pipe can have a significant impact; metallic pipes are more easily detectible than PVC or concrete, and pipes in good condition are more visible than corroded or rusted steel.
    • The condition of the soil, especially moisture content, will also play a role. Wetter soil will have a shallower maximum depth of GPR penetration, and will require pipes to be larger to be visible at the same depth. This means that even at the same site, the same pipe might be visible some days and undetectable on others, as the soil moisture changes throughout the year.
    • The condition of the surface. Flat asphalt, concrete, or short grass will yield the best results. A pipe which is visible under a parking lot may not be visible under adjacent heavy vegetation.

Environmental Services - Environmental services include but are not limited to locating underground storage tanks, locating utilities prior to soil boring, and locating areas of buried debris. Typical production is 1-2 acres per day.

  • Equipment performance and accuracy
    • 400 MHz antenna – This antenna allows for GPR signal penetration 6’-9’ through the ground pending conducive soil conditions being in the area.  Additionally, please expect our accuracy to be +/6” to the center of the located utility and +/-10% with regards to the depth indication provided.  This antenna is best suited for underground utility locating for most applications.
  • General limitations – In general the same limitations noted above for Underground Utility Locating apply to these services as well.  Please reference this list for information.

Reporting Options - GPRS offers a wide range of reporting options.  The options range from Basic Reports to CAD Drawings and 3D Laser Scanning (Truepoint Laser Scanning).  The general information about each report is listed below as a reference.  While each report has similar structure our reports are often customized to fit the needs of our clients.  Please let us know what reporting needs you have and we will create a reporting option that suits you.

  • Basic Report – This report includes a detailed description of the scope of work, inspection methods, and equipment used.  Also includes visuals such as site locations, images of data (up to 3-4), and site photos.
  • Comprehensive Report – This report includes what is noted in the Basic Report above as well as additional data screen shots (quantity to be determined by scope of work) and drawings/site sketches.
  • GPS mapping of located utilities/items – This report includes GPS coordinates of located items and reference items.  Please let us know in what format you would like the drawing. For example, Google Earth Image Overlay.
  • CAD mapping of located utilities/items - Please supply us with a CAD drawing of the area that we can add to.  This is considered an add-on service in conjunction to the GPS Mapping noted above.
  • 3D Laser Scanning - We also recommend that you consider the use of 3-D Laser Scanning technology for the data collection process.  This technology is excellent and extremely accurate (+/- 4-6mm).  It is capable of collecting data from above ground and, using the GPR results, adding the utilities locations below ground creating a 3D rendering or model.  If you are interested in the service please visit the following website or contact Ryan Hacker (419.283.5818 or rhacker@truepointscanning.com).

These are just a few of the non-destructive testing applications of GPR technology.  Please call us to discuss any projects not listed here.


Ground Radar Scanning
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