GPR Scanning Services by GPRS

Utility Locating & Concrete Scanning With Ground Penetrating Radar

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99.8% Accuracy | National Footprint | Rapid Response

GPRS’ nationwide team of SIM-certified Project Managers utilize ground penetrating radar (GPR) scanners, in concert with complementary technologies such as electromagnetic (EM) locating, to conduct precision utility locating and concrete imaging services with a 99.8% accuracy rate.

GPR is a non-destructive detection and imaging method that was originally invented in the 1930s as a tool for measuring the thickness of glaciers. GPRS played an instrumental role in popularizing the use of the technology for identifying subsurface elements underground or within a surface such as concrete. Today, we are the industry-leader utilizing GPR technology to conduct subsurface investigations to keep construction projects on time, on budget, and safe.

All Services GPRS Project Managers at a worksite.

///how does GPR Work?

A GPR scanner emits radio waves into a concrete slab or site subsurface, then detects the interactions between those signals and any buried objects such as utilities, rebar, post tension cable, or underground storage tanks (USTs).

The interactions between the radio waves and buried or embedded objects are displayed in a GPR readout as a series of hyperbolas. These hyperbolas vary in size and shape depending on the material composition of the located object.

It takes specialized training to interpret this data and determine the location and approximate depth of these buried/embedded objects. That’s why all GPRS Project Managers are certified in Subsurface Investigation Methodology, or SIM, which you can learn about here.

GPR can detect both metallic and non-metallic objects, making it a versatile tool for subsurface investigations.

///How GPRS Uses GPR Scanning to Locate Buried Utilities?

GPRS Project Managers most often deploy ImpulseRadar PinPointR GPR Scanners when conducting utility locating services.

These walk-behind units resemble push mowers and feature dual-channel operation (400 MHz low frequency and 800 MHz high frequency) that allows for one-pass locates with full depth range. They also have internal global positioning systems (GPS) that allows for data geo-referencing.

GPRS has gone a step further to ensure unparalleled accuracy in our utility locates, adopting real-time kinematic (RTK) positioning as the standard operating protocol for all our Project Managers and Field Team. Click here to learn more.

GPR technology, just like any tool, has limitations. Quality of the data produced by utility locating GPR scanners can be affected by the moisture content of the soil as well as interference from anything that emits the same frequency range as the scanner, such as cell phone towers. That’s why GPRS SIM-trained Project Managers deploy EM locators and other complementary technologies to compensate for the limitations of GPR to ensure you receive the data you need to stay on time, on budget, and safe.

PinPointR being used by a GPRS project manager.

///HOW GPRS USES GPR TO CAPTURE UNDERGROUND INFRASTRUCTURE IN HIGH-TRAFFIC AREAS

It took GPRS about three hours to complete the data registration, clean-up and individual line isolation for the roadway pictured above, captured with the high-speed 3D GPR array.

GPRS also operate high-speed 3D GPR arrays to capture data in roadways and right-of-ways. This unique GPR array can create 3D images of the subsurface at highway speeds when towed behind a vehicle. And, when paired with GPRS’ 99.8% accurate Subsurface Investigation Methodology, it can give municipal managers, civil and design engineers, utility managers, general contractors, surveyors, and facilities managers the vital utility information they need in a fraction of the time of a traditional utility survey.*

Learn More About Our High-Speed 3D GPR Array Services

^{*GPRS does not conduct SUE. The accuracy of our services support SUE level B.}

///How GPRS Uses GPR Scanning to Investigate Concrete Slabs

A man wearing a hard hat and safety vest is kneeling down to look at a tablet. | GPRS Images

When investigating a concrete slab for conduit and reinforcements like rebar, post tension cables, and more, GPRS Project Managers most often utilize the Proceq GP8800 Ground Penetrating Radar Scanner. Concrete GPR scanners are much smaller than walk-behind units, and generally offer a 400-6000MHz modulated frequency range that enables us to locate a wide variety of subsurface objects with one pass.

Thanks to their small size and wireless connectivity, concrete GPR scanners can easily investigate hard-to-reach areas. While the handheld unit features many of the same limitations as the walk-behind GPR unit, GPRS Project Managers are specially trained to use complementary technology to overcome these issues.

GPR scanning is a far more efficient and safe method for concrete imaging compared to the traditional method: Concrete X-ray. You can learn more about the differences between the two technologies here.

In addition to investigating what’s inside your concrete slab, GPRS can also use GPR to determine key slab information for structural engineers, like concrete cover and overlay thickness, concrete thickness, and even dowel placement. We can also employ reality capture technologies like 3D laser scanning and photogrammetry to capture our 99.8% accurate concrete scans to create comprehensive 3D BIM models of slab interiors.

Regardless of the size or scope of your site, GPRS has the training and equipment to evaluate your concrete structure.

///THE GPRS GREEN BOX GUARANTEE

An industry-leading, proprietary program that provides contractors the necessary assurance of safety when drilling, cutting, or coring through an elevated concrete deck. When GPRS places a Green Box within a layout before cutting or coring concrete, we guarantee it will be free of obstruction.

Problem

Electrical conduit strikes present a high risk of electric shock to the equipment operator and nearby workers. Strikes can also cause nearby operations and work to be shut down. Cutting, coring, or drilling through a post-tension cable can cause structural damage or injury. Severed post-tension cables can lead to compromised structural integrity, creating severe safety concerns for everyone involved.

efficency

GPRS Project Managers can accurately clear dozens of cutting/coring areas per day. Cutting, coring, and drilling through concrete clear of obstruction can significantly speed up the demolition process. When contractors can keep their schedule from experiencing delays due to line strikes and damaged reinforcement, change orders and budget overruns are decreased.

COST SAVINGS

It can cost thousands of dollars to repair damaged wire and conduit due to an electrical strike. Post-tension cable repairs and restressing can cost several thousand dollars per tendon. Cutting through a post-tension cable, critical rebar, electrical conduit, or other obstruction can cause a job site to be shut down, increasing costs.

Clear Communication

Green Box Guarantee information is presented directly on the surface of the coring location. GPRS performs post-job walkthroughs to explain all Green Box Guarantee locations and parameters. GPRS leads the industry in project accuracy. Year after year, our performance is   well over 99% accurate.

///GPRS COMMITMENT

DATA CONTROL = DAMAGE CONTROL

GPRS commits to:

Provide elite project managers with a proven 99.8% accuracy rate

Utilize multiple complementary technologies to locate and identify subsurface utilities and/or embedded features

Follow industry-leading SIM protocols to get the most accurate results, everywhere, everytime

YOUR NEXT STEPS:

Hire only SIM-certified utility locating and concrete scanning companies

Provide an explicit dig policy for your crews that specifies the use of SIM protocols

Put data accuracy and safety at the top of your list

///FREQUENTLY ASKED QUESTION

Can GPR scan concrete slab-on-grade?

Yes, it can. Unlike with X-ray, where both sides of a concrete slab must be accessible to obtain a picture of the subsurface structure, GPR only requires access to one side of a slab to obtain a comprehensive view of what’s inside. This makes it an ideal technology for evaluating concrete slab-on-grade.

Can GPR identify the difference between rebars, post-tension cables, electrical conduits, and other embedded materials?

GPR on its own does not tell you what type of object has been located, which is why it is not advisable to attempt to complete this type of work yourself. Fortunately, GPRS equips every Project Manager in the company with the skills and technology to interpret the data collected by a GPR scanner to identify the type of embedded material present. Every GPRS Project Manager is required to complete the Subsurface Investigation Methodology (SIM) training program, which involves 320 hours of field training and 80 hours of classroom training. Through this regimen, our Project Managers tackle real-world scenarios in a safe and structured environment where they can learn to tackle these challenges with the highest level of accuracy and professionalism.

How accurate is GPR with marking anomalies in concrete?

When operated by our highly trained Project Managers, GPR’s typical accuracy is +/- ¼” to the center of the object in concrete we locate: conduit, post tension cables, and rebar. We can also pinpoint the depth of every object we locate in concrete with an accuracy of +/- 10-15%. Because our accuracy while scanning with GPR is so high, we can offer you our professional opinion to help you know where you are able to drill without the risk of hitting any objects marked on the slab. For safety concerns, we always tell our contractors to move one-to-two inches from any marked line as they prepare to cut or drill to be sure they safely miss any embedded objects. We are so confident in the accuracy of our Project Managers that we introduced the Green Box Guarantee, which states that when we place a Green Box within a layout prior to you anchoring or coring concrete, we guarantee that area will be free of obstructions. If we’re wrong, we will pay the material cost of the damage.

Are there any health risks associated with GPR?

No. This concern usually comes from someone familiar with X-ray technology, which carries the health risk of radiation-exposure. This is one of many reasons why concrete scanning and imaging with GPR is considered a safer, more efficient, and ultimately more successful alternative to X-ray. The typical power output of a GPR antenna is less than what is produced by the cell phone in your pocket. As a result, there are no health concerns with our Project Managers, construction workers, or tenants in the building where scanning is taking place. Additionally, GPR scanning is a quiet process, so noise issues are also not a concern.

Can GPR be used to verify known measurements?

Yes. GPRS can use GPR to cross-check the measured depth and location of a located utility with existing as-built plans to verify the accuracy of plans.