GPR or 3D Laser Scanning In Concrete Construction?

Two Complementary Technologies Can Cover All The Bases For New & Existing Construction

GPR or 3D Laser Scanning In Concrete Construction?

Two Complementary Technologies Can Cover All The Bases For New & Existing Construction
A worker uses a GPR scanner to scan concrete in a parking lot.
Since 2001, GPRS has provided its clients with world class, precision concrete scanning services. 

When ground penetrating radar (GPR) burst onto the scene decades ago, it quickly replaced X-ray as the preeminent tool for precision concrete scanning. 

The advent of 3D laser scanning has led some to believe that it could soon do the same thing to GPR that GPR did to X-ray. However, if you dig a little deeper, you’ll find that GPR and 3D laser scanning work best as complements to one another to achieve the goal of keeping job sites safe and projects on time and budget.

Striking rebar or cutting through post-tension cables, utility lines, or any of the other potential hazards typically embedded in concrete can cause costly delays to a project. At its worst, it can – and far too often, does – cost the lives of workers. 

The risks involved with cutting, coring, or drilling concrete are numerous. Mitigating these risks is why GPRS was founded over two decades ago. GPR has proven invaluable to our company’s mission time and again as we have earned and maintained a better than 99.8% accuracy rate in utility locating and concrete scans.

GPR involves a signal being sent from a receiver into supported concrete slabs, or slabs-on-grade. The signal bounces off any material it encounters, creating a reading that experienced GPR technicians can interpret to determine what type of materials were located.

GPR has many advantages over X-ray:

  • GPR does not require radioactive material to function. 
  • X-ray requires access to both sides of a concrete slab, as the radioactive material needs to be placed opposite of a receiver. GPR only requires access to one side of the slab.
  • There is minimal set-up and/or teardown time required for GPR equipment. X-ray, however, requires significant lead time as more than likely the entire job site will need to be shut down in order to mitigate radiation exposure.

GPR can locate virtually any material that can be found hidden within a concrete slab. GPRS’ highly trained Project Managers bring unmatched attention to detail to their craft that ensures you know what’s hidden and where before you drill, cut, or core.

3D laser scanning, a relatively new technology that is gaining traction in the concrete scanning industry, is proving to be invaluable during the planning and construction phases of a project. GPRS acquired TruePoint Laser Scanning in June of 2022 to complement our existing capabilities and continue offering our clients the industry-leading service we’re known for.

While some believe that 3D laser scanning could someday replace GPR much like GPR unseated X-ray scanning, 3D and GPR work best when used in concert with one another. Think of a golfer deciding between clubs before they attempt a shot. 3D laser scanning and GPR aren’t both drivers; they’re two different irons, each invaluable to have in the bag because they’re useful in different situations.

3D laser scanning is gaining popularity in the construction industry, mainly due to its varied applications. Sophisticated 3D laser scanners such as those produced by German company Leica can be used to capture millimeter-precise as-built drawings and data of building and sites with minimal interference to construction. Every inch of a site can be captured digitally by 3D scanners in a relatively short amount of time. When the scans are combined, the result is a digital twin of the facility that can be used to check for issues, accurately prefabricate materials off-site, refer to for O&M needs post-construction, and more.

Scanning a site prior to the pour of a concrete slab eliminates the potential for mis-measured conduits or sleeves that would normally lead to costly change orders if not found until after the fact. Scanning a concrete floor prior to it curing allows for the chance to correct levelness and flatness before the material becomes nearly impossible to manipulate. 

A 3D laser scanner sits among rebar and conduits where a concrete slab will be poured.
Utilizing 3D laser scanners to scan prior to the pour of concrete slabs creates accurate as-built drawings and other data that can be used for years to come.

GPRS/TruePoint Project Managers use a variety of technologies when conducting 3D laser scans. This includes the long-range, Leica P-Series ScanStations, which deliver the highest quality point cloud data and HDR imagery, and the Leica RTC360 3D laser scanner that, when combined with the Cyclone Field 360 mobile app, can capture and automatically pre-register scans in real time.

We also employ the Matterport Pro3 and Pro2 camera systems to create virtual 3D models, point clouds, layouts, floorplans, and even walkthroughs, tours, and schematic maps.

3D laser scanning has its limits. While it provides valuable data both before and during new construction, it cannot detect hidden obstructions in existing concrete structures. 

That’s where you need to be able to pull GPR out of the bag. 

3D laser scanning can generate accurate as-built data for buildings and sites that can be used for decades to come for O&M, or when renovation work takes place. GPR is vital when you need to know the precise locations of all potential hazards hidden within existing builds. 

GPRS’ multi-pronged approach to precision concrete scanning is key in our quest to eliminate utility strikes and mitigate the risks associated with working with and around concrete. The addition of 3D laser scanning to our already robust toolbox means that our Project Managers can now use GPR and 3D laser scanning in concert to meet our clients’ individual needs. 

Wherever you are in your project’s life cycle, GPRS has the tools and services to ensure that you Visualize The Built WorldTM in a safe and cost effective way.

What can we help you visualize?