GPRS Concrete Scanning Aids Alexandria Reno Project

GPRS Concrete Scanning Aids Alexandria Reno Project

As the world grappled with the realities of the COVID-19 pandemic, a group of GPRS team members stepped up to the plate to keep a high-stakes construction project on time, on budget, and safe.

In March of 2020, GPRS Field Service Directors Bryan Vickers and Larry Wade, and Market Segment Leader, Rhett Teller, were working in the D.C., Maryland, and Virginia (DMV) area when Wade heard of a substantial construction project that required precision concrete scanning and imaging services.

The client, WCS Construction, was overseeing the complete renovation of an existing 12-story building in Alexandria, Virginia. The building in question was the former Crowne Plaza Hotel, which was being redeveloped into a 13-story, 120-unit residential condominium tower.

The structure featured post-tensioned concrete slabs that would need to be cored through to run new utilities such as electrical conduit.

“Larry called me and he’s like, ‘Hey man, I just got this call, it sounds like a really big project, and it sounds like they’re pretty urgent,’” Vickers recalled.

Coring or sawing through post-tensioned concrete is one of the most dangerous activities that occurs on a construction site.

Damaging post-tension cable can result in serious structural failure, which can lead to injuries or even deaths. Repairing damaged post-tension cable can cost upwards of $10,000 per cable and take 3-5 days to complete. There is also additional cost incurred in downtime and schedule overrun.

The dangers associated with cutting and coring concrete are what led GPRS to create Concrete Sawing & Drilling Safety Week, which this year runs January 29-February 2. You can learn more about this safety initiative here.

In Alexandria, the contractor anticipated needing to core in roughly 400 different locations per level. That’s at least 4,800 chances for costly and dangerous subsurface damage.

Fortunately, GPRS concrete scanning services can help mitigate the risks associated with subsurface damage by providing construction companies control and confidence prior to cutting or coring a slab.

How Concrete Scanning Works

Precision concrete scanning primarily relies on ground penetrating radar (GPR) to see what’s hidden within a slab or structure.

GPR involves sending a radio wave into a concrete slab and reading the interactions between the wave and any subsurface objects. These interactions are displayed in a reading as hyperbolas – smooth curves lying in a plane.

The color of the hyperbolas varies depending on what type of subsurface object is located. Metallic objects will appear primarily white in a GPR reading, while non-metallic objects will appear primarily black.

The shape of the hyperbolas also varies depending on what was located. Post-tension cables, for example, are run in bundles of two-to-five cables, so they typically have a brighter and wider reaction than rebar.

GPR scanning services reveal rebar, post-tension cable, electrical conduits, and more. It’s also an effective method of structural review including concrete slab measurement and rebar spacing.

A worker instructs a second worker by pointing at a tablet.
GPRS Project Managers all undergo training based on the Subsurface Investigation Methodology (SIM), the industry-leading education program for concrete scanning, utility locating, video pipe inspection, and leak detection.

The GPRS Difference

Of course, even the best technology is only as good as the person using it.

And that’s where WCS had a problem. Because before they were our client, they employed a local concrete scanning firm to scan their building.

When Wade, Vickers, and Teller arrived on site to evaluate the project, they learned that the other firm had multiple technicians on the job, and were clearing 12-14 coring locations per day.

“I had full confidence that we could show the client that we could not only out-produce this other company, but perform better work as well,” Wade said.

It started with one coring location, which Wade agreed to scan himself, at no cost, to demonstrate to the contractor the quality and efficiency of the GPRS concrete scanning process.

This process is anchored by Subsurface Investigation Methodology, or SIM, the industry-leading training program for concrete scanning, utility locating, and video pipe inspection.

GPRS Project Managers are required to complete SIM certification, which means logging 320 hours of field training and 80 hours of classroom training. This process prepares them to tackle whatever they may encounter in the field.

We are so confident in the accuracy of our SIM-certified Project Managers that we offer the Green Box Guarantee, which states that when we place a Green Box on a concrete slab, we guarantee that area will be free of obstructions when the client cuts or cores. If we’re wrong, we agree to pay the material cost of any damage that occurs.

Leaning on his SIM training, Wade quickly scanned that first coring location.

The contractor was so impressed by Wade’s work that he agreed to let him do more.

“Larry was like, ‘I’ll do 15 spots right now,’ and he went up there in an hour and a half and crushed 15 spots out, and his markings were flawless,” Teller said.

“I saw a huge opportunity, not only for our company, but for the customer as well to save hundreds and thousands of dollars, to be honest with you,” added Wade. “Because they were spending a full day (on the other company) for literally four hours of work, and in those four hours they were getting done a third of what our production would have been.”

And where the other firm would only indicate something was found, GPRS Project Managers are trained to identify and label what was located.

“This was a post-tension slab, with conduit in it as well,” Wade said. “So not only were we outproducing that other firm per hour with the number of locations we were doing, but we were labeling, we were differentiating post-tension cable from conduit, from reinforcement, when they weren’t. They were just putting lines in everywhere, and it was a pretty congested slab in some areas.”

A worker scans a concrete wall while looking at a tablet.
GPRS Concrete Scanning Services help you prevent subsurface damage on your job sites by visualizing what you can't see.

Intelligently Visualizing The Built World®

Because the other concrete scanning firm was contracted for four floors, GPRS was initially asked to scan just two additional levels. Those two levels, however, quickly turned into more. Over the next five months, GPRS Project Managers were a constant presence at the job site.

“We had multiple guys on the project,” Teller said. “It wasn’t two, it wasn’t three, we had sometimes four, five, six guys out there at one time because, again, that’s how important this project was. It turned out to be something that could keep everybody busy.”

“[The contractor] understood the importance of saving money as well as what he was getting from that other company,” Teller said. “It was just subpar compared to what we were giving him.”

From skyscrapers to sewer lines, GPRS Intelligently Visualizes The Built World® to keep projects on time, on budget, and safe. And with over 500 Project Managers strategically stationed in every major U.S. market, you never have to wonder, “are there concrete scanning companies near me?”

What can we help you visualize? Click the links below to schedule a service or request a quote today!

Schedule a Service
Request a Quote