Are you confident that you know what is within your structure?
What is GPR?
Principal:
GPR is an acronym for Ground Penetrating Radar.
GPR technology uses high frequency electromagnetic waves.
These reflected waves are then detected by the radar equipment and allows us to determine the locations of objects within the structure.
Ground can be soil, rock, concrete, asphalt, wood, any substance non-metallic.
Data Accumulation:
The radar unit emits and receives reflected signals up to a thousand times per second.
These signals are viewed by the field operator on site and an immediate analysis is performed.
The data can be collected in simple line or grid format.
Cobra does both of these scan types at every location.
The grid scan format will produce a map of any targets or flaws located in the concrete. This is then mapped out by the operator and they will transfer the data to the grid which is left behind for the clients to review the findings.
Using this method, both the line scan and grid scan, we can see virtual slices in the image to determine the depth and sometimes an estimated size of the object.
The data is then downloaded to a computer and stored for further data analysis if required.
A 3D image of the data can also be created for engineering purposes.
All data is required by law to be kept on file for 7 years.
GPR Data Analysis:
GPR travels through many different materials. Different types of concrete, asphalt and fill material may have varying amounts of water saturation and this will have different dielectric and conductive properties which will effect the GPR waves.
After freshly poured concrete, it is recommended to wait 1 month after it has cured to perform scanning.
The most important quality of concrete scanning is to isolate the hazards in your concrete and find you a safe place to cut or drill.
Why Scan?
Safety when cutting or coring
• cutting a gas line can be fatal
• cost future work
• project delays
• be extremely costly
Structural Integrity
• severing a post-tension cable can
be dangerous and compromise
• structural engineers often prefer
you avoid rebar
GPR can accurately detect metallic and non-metallic reinforcement, pipes and current carrying electrical in and below slabs up to a limited depth. GPR can also detect flaws and voids, the absence of mortar in concrete block walls, map rebar, post tension cable and pipe. We can verify slab thickness, determine the depth and size of the object in most cases.
