What Are Best Practices When Cutting or Coring Concrete?

What Are Best Practices When Cutting or Coring Concrete?

When engineers in Deming, New Mexico, needed to saw cut into a concrete slab within a warehouse, they contacted GPRS to mitigate the risk of subsurface damage by utilizing our precision concrete scanning services.

The engineers needed to know the location and depth of utilities and any other unknown subsurface objects running through the slab. They also wanted to know the thickness of the slab.

Coring or cutting through rebar or post tension cables in concrete can result in immediate structural failure that endangers everyone on site – and costs a lot of money to repair. According to a recent study completed for GPRS by Finch Brands, the average cost to repair damage to rebar or conduit embedded within concrete is $12,000.

To prevent this, GPRS used a ground penetrating radar scanner to locate the utilities, reinforcing steel, and other anomalies within the concrete in the Deming warehouse.

A gloved hand holding a ground penetrating radar concrete scanning antenna.
Ground penetrating radar (GPR) is a non-destructive detection and imaging technology that utilizes radio waves to evaluate what’s inside concrete or buried underground.

Ground penetrating radar (GPR) is a non-destructive detection and imaging technology that utilizes radio waves to evaluate what’s inside concrete or buried underground. The GPR scanner emits a radio signal into a structure, then detects the interactions between the radio waves and any subsurface objects – metallic or non-metallic. Those interactions are displayed in a readout as a series of hyperbolas, which vary in size and shape depending on what type of material has been located.

Professional concrete scanning technicians like GPRS’ SIM-certified Project Managers are specially trained to interpret these readouts to provide accurate information about the location and depth of buried objects.

SIM stands for Subsurface Investigation Methodology, the industry-leading training program and specification for not only concrete scanning but also utility locating, video pipe inspections, and leak detection.

All GPRS Project Managers are required to achieve SIM 101 certification, which includes a minimum of 320 hours of field training and 80 hours of classroom training.

During their field training, the trainees are paired with experienced GPRS Project Managers who walk them through the finer points of Intelligently Visualizing The Built World®. The classroom education takes place at GPRS’ state-of-the-art training facility in Sylvania, Ohio, where the trainees utilize the site’s innovative, 3,000-square-foot training slab that’s designed to mimic even the most complex conditions they might encounter in the field.

All that training meant the Project Managers in Deming were prepared to meet the engineers’ needs. We scanned the concrete slab and marked our findings directly on the concrete with crayon at their request to ensure easy cleanup upon project completion.

The PMs were on site within 24 hours of initial contact with the client, ensuring the project’s schedule remained intact.

A GPRS Project Manager kneeling on a concrete slab and using a ground penetrating radar scanner.
GPRS used ground penetrating radar to locate the utilities, reinforcing steel, and other anomalies within concrete and protect you from subsurface damage.

A New Era of Infrastructure Mapping

Even GPRS’ 99.8%+ accurate concrete scanning and utility locating services aren’t worth much if the data we collect isn’t at your fingertips when and where you need it.

That’s why we created SiteMap® (patent pending), our cloud-based project and facility management application that provides accurate existing conditions documentation to protect your assets and people.

All GPRS clients receive a complimentary SiteMap® Personal subscription whenever they hire us to perform a job, allowing you and your team to easily, yet securely access and share the field-verified data you need to build better from any computer, tablet, or smartphone.

In the case of concrete scanning, GPRS’ in-house Mapping & Modeling Team can export the GPR concrete scans and field markings captured with 3D photogrammetry to create accurate existing condition as-builts to give you the information you need in a format you can easily work with and share. And that data will be uploaded into SiteMap®, so even after the markings we leave on site fade or are washed away, you still know where it’s safe to cut or core.

The Green Box Guarantee

GPRS isn’t just confident in the results of our concrete imaging – we guarantee them.

The GPRS Green Box Guarantee states that when GPRS conducts a concrete scan and places a Green Box on your slab prior to you anchoring or coring that concrete, we guarantee the area within the box will be free of obstructions.

If we’re wrong, we agree to pay the material cost of any damage that occurs.

The Green Box Guarantee helps prevent potentially life-threatening injuries and damages, eliminates project delays, costly repairs, and unexpected change orders, and ensures clear communication between you and our field team members about where it’s safe to break ground. It’s just one way we are working to achieve our goal of 100% subsurface damage prevention.

From skyscrapers to sewer lines, GPRS Intelligently Visualizes The Built World® to keep your projects on time, on budget, and safe.

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

Frequently Asked Questions

How is ground penetrating radar used to identify tendons vs. rebar in a post-tensioned slab?

In post-tensioned structures, we typically find one mat of support rebar near the base of the slab. This mat is generally consistently spaced and remains at a constant elevation. Post tension cables are generally found above this support mat and “draped” throughout the rest of the structure. The elevation of the cable is usually high near the beams and column lines and drapes lower through the span between beams and column lines. Knowledge of these structural differences allows us to accurately differentiate between components. Our Project Managers will leave you feeling confident in our findings and in your ability to drill or cut without issue.

Can GPR determine the difference between rebar and electrical conduit?

Ground penetrating radar can accurately differentiate between rebar and electrical conduit in most cases. We have an extremely high success rate in identifying electrical lines in supported slabs or slabs-on-grade before saw cutting or core drilling.

Additionally, GPRS can use electromagnetic (EM) locators to determine the location of conduits in the concrete. If we can transmit a signal onto the metal conduit, we can locate it with pinpoint accuracy. We can also find the conduit passively if a live electrical current runs through it.

The combined use of GPR and EM locating allows us to provide one of the most comprehensive and accurate conduit locating services available.

Will there be a Green Box placed on every concrete slab that I have scanned?

No. Our Green Boxes communicate to our clients that all critical targets such as rebar reinforcement, electrical conduits, and post tension cables are absent, and no obstruction is present. We place Green Boxes on elevated concrete slab locations that we’re confident are clear to core, cut, or drill through. If we aren’t confident that you won’t hit anything, we won’t place a Green Box on the slab.