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Colorado Concrete Scanning with Ground Penetrating Radar

Colorado Concrete Scan

gpr cost

When planning either a renovation or repairs in a concrete structure, there is the risk of encountering rebar, conduits, and post tension cables during cutting, coring, or drilling. A GPRS technician provides the technology and technical proficiency to help clients complete their project safely and on budget. GPRS technicians are highly trained, fully insured, and have the industry’s best experience in order to provide accurate and professional scanning. GPRS can scale its services to meet the project size, from a large 3-week construction project to a one-hour locate project.

GPRS has highly trained professionals in all major markets in the U.S. as well as in Canada. GPRS’s extensive network enables our technicians to respond quickly to all job requests, in most cases within 24 hours.

Determining factors for the cost of a concrete scanning project:

  1. Location of the project objective
  2. The type of surface being scanned, such as hollow core, post tension, or slab on grade applications
  3. The amount of wire mesh, rebar, or post tension reinforcement that is suspected in the concrete
  4. The number of locations at the site that need to be scanned and the distance between each location
  5. Lift or scaffolding availability for a concrete wall or ceiling scan
Concrete Scanning

Applications of Ground Penetrating Radar:

Detection of Reinforcing Steel
GPRS trained technicians are able to locate rebar or post tension cables within the concrete using GPR technology. A grid will be marked directly on the work surface to ensure safe and efficient drilling that will preserve the integrity of the structure and reduce the need for repairs or patching, ensuring that clients can conduct core drilling and repairs without accident, injury, or delay. GPR scanning is a useful tool when preparing for a renovation that includes electrical outfitting, plumbing, fire protection services, drain installation, or duct work.

Detection of Embedded Electrical Services
When drilling in commercial and industrial locations, accurate detection of electrical conduits is essential for preventing safety risks, power outages, and expensive damages. GPRS provides comprehensive scanning and detection services prior to drilling and cutting which allows clients to avoid conduits and to drill safely into and through concrete slabs.

Detection of Voids
GPRS technicians are able to locate air pockets and voids hidden in the sub-grade or below concrete or asphalt surfaces. This degradation occurs over time due to overuse, impact, or erosion but is often undetectable on the surface. GPRS ground penetrating radar technology can help you identify these areas and avoid collapses.
locate post-tension cables

locate electrical services

Void Scanners

Video: Concrete Scanning Technology & Capabilities


Video: Concrete Scanning Costs and Price Quotes GPRS


Training and Safety:

Safety is a top priority at GPRS.  All of our technicians receive extensive on-site training and complete OHSA 10-hour construction training. Specifically, our new techs ride with senior technicians to observe each application and learn the job. After completing the manufacturer’s training course, the techs will return to the field with the senior technicians who now act in a supervisory role as the techs hone their skills and prepare to enter the field full time.

When determining cost for your concrete imaging project, these are some considerations:

1. Location of the project and objective of the concrete imaging.

2. What kind of concrete subsurface are we scanning (i.e. hollow core, post tension, slab on grade)?

3. How much wire mesh, rebar, and post tension reinforcement is suspected in the concrete?

4. How many locations at the site need to be scanned and how far apart are they?

5. If we are going to scan a concrete wall or ceiling, will a lift or scaffolding be available for our use or does our technician need to arrange for this equipment?



Using Ground Penetrating Radar To Perform Concrete Imaging:

Common Questions Answered

GPRS continues to see an increase in the use of ground penetrating radar to scan or image concrete slabs. Concrete imaging with ground penetrating radar is a successful process that results that ensure construction, cutting, drilling, etc. can continue without impact to the facility or project. We wanted to take a moment and discuss some common questions with regards to using GPR to scan concrete.

1. Often we are asked if ground penetrating radar can scan/image concrete slab-on-grade.

The answer, simply, is yes. This question often comes from someone who is familiar with concrete “X-Raying”. While X-Raying concrete is still a valid technique for determining the location of reinforcing steel it is limited to elevated concrete slabs only. This is because you need to have access to both sides of the concrete to perform an x-ray. One side for the radioactive isotope and the other for the film. Ground penetrating radar is a completely different technology.

GPR only needs access to one side of the concrete. This fact makes it ideal for scanning concrete slab-on-grade applications.

x ray, x-ray, xray concrete florida

2. Can Ground Penetrating Radar determine the difference between rebar, post tension cables, electrical conduits, etc.?

This is a more complicated answer than the question above. While the technology (ground penetrating radar) does not determine what type of object/anomaly is being located we (the technicians) are very good at determining what type of reinforcing steel or electrical conduit is present. Take the photo below for example…

rebar, post tension cables, electrical conduits

This photo shows a typical post tension cable mark out. We are able to locate, using the radar, all of the reinforcing steel anomalies. We then mark the findings on the concrete and are quickly able to determine, based on the pattern, what each marking indicates. Most often when something is on an angle through a square layout it will be a conduit. Further, you will have a typical rebar pattern with 12-18” centers. Post tension cables tend to be spaced further apart depending on the design of the building and whether they are banded or uniform tendons.

As you can see, the real answer to the question of whether ground penetrating radar can tell the difference between rebar, post tension cables, electrical conduits, etc. is YES and NO. The radar can’t but an experienced technician can interpret the data the radar discovers to provide you with an accurate representation of what is in the concrete.

3. How Accurate is Ground Penetrating Radar with marking anomalies in concrete?

We have found that our typical accuracy is +/- ¼” to the center of the object (conduit, post tension cables, rebar) being located. GPR can also inform you of the depth of the object in the concrete. We have found that our typically accuracy when locating the depth of an object embedded in concrete is +/- 10%.

accuracy of gpr

This photo, again, shows a typical elevated concrete slab layout after we finish scanning. You can see that all rebar, post tension cable, and walker duct were marked on this layout. Because the radar’s accuracy is so high we can confidently tell contractors where they are able to drill without the risk of hitting any of the objects shown in the picture. For safety and caution we instruct all contractors to stay 1 inch from any line they do not want to hit. This allows for bar/tendon thickness.

4. Are there any health risks associated with Ground Penetrating Radar?

Again, this question often stems from someone who has experience with x-raying concrete. As mentioned, x-ray continues to be a viable and accurate testing method for mapping objects in concrete but it does come with an inherent health risk. Most x-ray companies recommend that you clear the area where the “shot” is taking place.

Because the typical power output of a radar system is less than the cell phone most of us carry in our pocket it is completely SAFE to work around. There is NO concern over health risks of our technicians, your employees/team members, or other tenants in the building. Further, the radar does not emit sound and operates almost silently so there is no noise disruption.

health risks of gpr

5. How long does it take to scan an area for core drilling?

Ground penetrating radar is an extremely efficient and fast technology able to scan large areas in with ease. Our standard layout for a typical core drilling location is 2’x2’ in size. It will likely take us about 10 minutes to scan and mark this area.

scan an area for core drilling with ground penetrating radar

6. Is there a reason why I should hire GPRS and not buy my own equipment?

This is a GREAT question and one that we are getting more frequently. While the cost of a GPR system may seem inconsequential on a large project there is more to concrete imaging than just having the equipment. We truly believe that half of the job involves knowing how to read the GPR data screen. The other half is being able to determine what the data is telling you.

This comes through experience. Only through experience can we interpret the data on the screen to tell you what anomaly indicates rebar, post tension cables, or electrical conduit. Only through experience and industry knowledge can we take our construction information and apply it to the data that we see after imaging the concrete and provide accurate answers to your questions.

locate rebar, post tension cables, or electrical conduits

There are many other questions that we are asked with reference to scanning concrete. Those questions involve other aspects of our scanning process including; can you locate voids below concrete? Can you scan walls or ceilings? Can you locate rebar in a CMU Block wall? For answers to these and other questions you can visit our FAQ page on the website or, better, call your local technician who would be happy to answer any and all questions as well as provide you with pricing and availability for service.

Unknowns Beneath the Surface
Unknowns Beneath the Surface

Failure to Detect Unknowns Beneath the Surface
Damages and Delays
Damages Delays


Example of Damaged Conduits. Call Before You Cut! Rebar Locating in Denver, Colorado

Example of Damaged Conduits. Call Before You Cut!

Concrete Scanning in Denver, Colorado

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