What do GPR surveyors do?

Chimney flue location

Chimney flues provide a pathway for gasses to vent outwards from a chimney, boiler, or any similar device. These are usually found constructed within walls, so they are not visible to the naked eye. A GPR surveyor can locate the chimney flue in moments through the use of GPR equipment.

Concrete floor slab surveying 

GPR experts can survey concrete slabs. Depending on the client’s specific requirements, we can use GPR to ascertain how thick a concrete floor slab is and further determine what lies underneath the slabs. This might include reinforcement, post tension cables, conduits, drainage, pipes, voids, and anything else that could affect the concrete space’s purpose.

Locating buried obstructions

When working on any construction, a single obstruction can cause many issues and delays to the project. Ground-penetrating radar surveyors are usually called before work on construction begins to ensure that such problems are avoided, saving time and money. GPR equipment can detect pipes, foundations, old tunnels, drainage, and other objects that could be hit beneath the ground when excavation work begins.

Pavement surveys

Pavements undergo a great deal of use and pressure upon them, which means it is critical to check their integrity regularly. Factors such as increased moisture, shifts in the ground, and the presence of voids could put the area, and therefore pedestrians and other traffic, in jeopardy. Using GPR technology to survey pavements means that risks can be appropriately assessed, and the next steps can be planned.

Rebar location and mapping

Rebars are found in any solid concrete construction. Usually in the form of either meshed steel wires or solid steel bars, they ensure the integrity of the concrete, especially if it is frequently put under stress or tension.

When rebar location and mapping is done, surveyors assess how thick the concrete is and how deep the rebars are, including the number of layers, spacing between bars and what’s found around the steel and the concrete. This is extremely useful if work has to be carried out in the area around the concrete so the contractor can avoid the rebars.

Underground void detection

Voids below ground level can affect construction work, industrial activity, and any other similar projects. These can be caused by sinkholes, ground movement, or material washout. Underground voids can also have an impact on the overall safety of the area, making it critical to detect them early on.

Through GPR scanning, a surveyor can discover areas where these voids are present. Once the data is processed, it will be easier to determine the impact they might have on the surrounding space.

Under-floor heating pipes detection

Some heating systems are laid out underground because of the huge benefits doing so provides. Underground heating is energy-efficient, easy to install, offers more design opportunities and can be used regardless of the type of flooring you have. However, locating the underground heating pipes in future can be difficult, especially if you need work to be carried out on the floor above it or on the heating system itself.

With the help of GPR experts from KB Surveys, these heating pipes can be located without having to ruin the flooring.

Utility location

It is common for utility lines to be laid out underground. This is more visually appealing, helps create more space on the surface and ensures that civilians are protected from dangerous cables, pipes, and other types of power lines. However, it can be tricky to access these lines, especially when work needs to be carried out underneath or above the surface.

Surveyors performing a gpr utility survey can easily detect where these lines are without digging through the surface. They use both GPR and electromagnetic location (EML) to pinpoint specific areas where utility lines are laid.

These are just some critical activities that GPR surveyors perform to make it easier for other experts to do their job efficiently.

What to look for in a GPR service

Ground-penetrating radar surveys are a critical part of a whole range of projects, as noted above. Due to the essential nature of GPR surveys, choosing the right surveyors for any project is important.

In looking for a GPR service, ensure that they are quoting the right GPR survey cost for the project. Avoid quotes that are surprisingly cheap; otherwise, you may find that the quality of service is compromised. Similarly, steer clear of prices that are so high that they put your resources, and therefore your budget, in jeopardy.

Here at KB Surveys, we are a team of trusted experts with years of experience across various industries. This means that no matter what your requirements are, we will find ways to deliver services that are both affordable and unique to your needs. Call us now on 020 3931 5759 to discuss your surveying needs.

What is a GPR survey?

Ground Penetrating Radar (GPR) is a survey technology that uses an electromagnetic energy signal to map the subsurface. A transmitter, a receiver, and a signal encoder are typically used.

GPR is a highly effective survey strategy for mapping what lies below a variety of materials, including concrete, masonry, and asphalt.

How much does a Ground Penetrating Radar survey cost?

The majority of surveys cost between £18,800 and £36,000. GPR surveys can cost anywhere from £780 to £1,800 per day, depending on the amount of interpretation necessary and whether a report is needed.

Can GPR 'go through' concrete?

GPR can penetrate through Soil, rocks, and most artificial materials, such as concrete, however the maximum penetration will depend on the electromagnetic properties of the material. A medium frequency GPR signal can penetrate up to a few meters in concrete, or for engineering purposes, a ground penetrating radar assessor can use a high frequency GPR to map rebar up to 0.5m beneath reinforced concrete surfaces.

Can a Ground Penetrating Radar find tunnels?

Yes. The ground-penetrating radars used by geophysical penetrating radar inspectors are perfectly capable of identifying tunnels deep down within the ground. However, the effectiveness of GPR systems for identifying deep tunnels is typically dependent on soil types, specific objectives, and subsurface geological features.

How accurate is a Ground Penetrating Radar?

GPR surveys are very reliable. But while GPR is by far the most effective, non-destructive testing method out there, it isn’t without flaws. The accuracy is affected by many variables, such as the scanning area’s characteristics, the materials present, and the person using the equipment. This means it’s crucial to work with experts in the field when commissioning a survey.

Advantages of using GPR on buildings

GPR is considered safe because it emits a very low level of electromagnetic energy with an average power 1000 times less than that of a mobile phone. It usually only requires access to one side of a wall or slab. It also often only requires one GPR surveyor and is capable of producing real-time findings. Moreover, these actions can be carried out during regular business hours with minimal impact on a building’s day-to-day operations.

When it comes to scanning concrete with GPR surveys, there are a variety of advantages to be gained by working with expert GPR survey companies:

• Accurate Imaging- GPR can provide accurate pictures, allowing precise analysis of slices from various depths to determine the orientation and depth of any embedded objects.
• Workflow Integration-  Ground Penetrating Radar examiner can smoothly integrate with the customer’s project management and workflow, especially for larger projects.
• Difficult Sites- because GPR sensors are small, they can be used in restricted spaces and from almost any angle. They can also be used on ceilings, walls, and floors.
• Non-Invasive- the testing and evaluation are non-intrusive, carried out without any dangerous, destructive, or costly testing procedures.
• Health and Safety- GPR is not only non-hazardous to infrastructures; it also poses no risks to the general public or operators. A ground-penetrating radar evaluator can safely use their equipment even in busy public places without endangering others nearby.
• Flexibility- GPR is frequently categorised as a collection of tools in one. The expertise of a GPR contractor allows business owners to get involved in the most up-to-date activities and ventures.
• Ownership- the most recent GPR systems are simple and economical, with minimal training and no certification costs involved. Most operations have been automated due to the enhancements made in data processing, including automatic reports as appropriate.

Using GPR with concrete

A Ground Penetrating Radar can be utilised on various land and other surfaces, including rock, soil, ice, fresh water, pavements, and constructions, both concrete and non-concrete. GPR uses a series of radar pulses to create an image of the subsurface. GPR survey services essentially use electromagnetic radiation in the microwave band of the radio spectrum (i.e., UHF/VHF frequencies) and detect the reflected signals from subsurface structures to ascertain ‘hidden’ objects, changes in material, voids, and cracks.

Air-launched and ground-coupled GPRs are the two most prevalent forms of GPR for bridge surface measurement. The former employs directional antennas pointed at the surface from a height of 305 to 508 mm, while the latter uses an antenna located extremely close to the roadway/surface (less than 25mm.)

GPR surveys UK-wide can also be used to check for quality assurance/quality control (QA/QC) on a new bridge deck. This will determine whether the rebar depth is within acceptable limits. The top rebar mat is often measured during QA of the bridge deck after it has been poured to confirm it is within the depth range stipulated in the bridge plans.

GPR surveyors offer specialised services to individuals and businesses for construction, exploration, and research purposes. To maximise the benefits of the services provided by these professionals, the team here at KB Surveys offers tips and all the support you might need. Visit our homepage to learn more.