Ground Penetrating Radar (GPR) For Infrastructure Inspections

Robot to inspect bridge

GPR for Non-Destructive Testing (NDT) Inspections

Infraspect utilizes a highly specialized and customized GPR system for NDT to imaging the subsurface. Infraspect’s GPR configuration is invaluable for bridge inspections, roadway inspections, airport runways, underground utilities, concrete structures, and parking garages.

Infraspect uses an enhanced version of GPR which is a geophysical NDT method that uses radar pulses to image the subsurface. This NDT method uses electromagnetic radiation in the microwave band of the radio spectrum and detects changes in subsurface materials. GPR provides a non-destructive method of inspecting the surface of the ground to assess roadways & bridges, locate utilities and pipes, find voids in post-tension tendons and locate rebar and utilities prior to digging or construction to keep the construction site safe.

Infraspect's GPR Capabilities

Locate underground utilities
Slab on grade conduit locating
Concrete analysis
Locate reinforcement prior to cutting
Locate sewers
Locate pipes
Locate post tension cables
Locate subsurface voids
Concrete assessment
Gpr

GPR for Bridge Inspections

Infraspect specializes in bridge inspections with GPR. Infraspect has modified its GPR equipment to uniquely conduct bridge deck and bridge approach way assessments and provide the results that the Department of Transportation (D.O.T.) requires from their bridge inspections. By having the experience and expertise we are able to provide them with a complete bridge deck assessment for the same price that they currently have budgeted for the manual subjective inspections. Our results will provide the D.O.T. with the data they need to properly allocate assets and manage their manpower and repairs.

Infraspect’s multifrequency systems can quickly perform the following bridge inspections:

Deck and approach slab deterioration condition assessments Identifying 12 levels of deterioration
Reinforcement pattern and cover over reinforcement
Deck and approach slab delamination
Voids and water under approach slabs
Loss of fill density, voids and water within fill under approach slabs
Water intrusion through abutments and behind backwall

Updating 50-year-old chain dragging and inspection services with GPR will help save billions in infrastructure costs. Finding early-stage deterioration and making timely repairs will help maintain a healthy infrastructure for years to come. Infraspect developed a patent-pending process called BridgeScan® which is a complete bridge deck and bridge approach way assessment.

BridgeScan® takes GPR and the reporting to the next level giving the D.O.T. an action plan that allows for them to better allocate assets and preserve the service life of our bridges.

Bridge inspection

Infraspect’s Bridgescan® Locates Approach Slab Deterioration Condition Assessment Identifying 12 Levels of Deterioration.

Void Formation
Delamination
Rebar Assessment
Debonding
Rebar Placement
Cover Thickness
Water Intrusion
More…

Bridge Deck and Bridge Approach Slab Levels of Deterioration With GPR

GPR will quickly replace the current manual methods of bridge inspections providing far greater detail of the bridge deck. GPR can peer through the concrete to provide detailed data 15 feet below the surface.

See below the GPR images and how we interpret them. The configuring of the GPR is based on the age and the components of the bridge. At Infraspect we have an expert bridge inspector configure and analyze your scan results. Just like having your doctor interpret your MRI, you would not like a technician without bridge experience to analyze your bridge GPR results.

Old bridge inspection method
Ground penetrating radar image

This is an image of a bridge deck that has been in service for 26 years. The total area of the deck shows 8.4% deterioration with small pockets of moderate to moderate/sever 19% to 23% deterioration. With Infraspect’s BridgeScan® you get 12 levels of deterioration allowing you to better budget for maintenance and repairs.

Gpr ground penetrating radar wave

This is an image of a deck deterioration assessment showing the majority of the deck in good condition with a section of the deck showing severe deterioration / delamination in red. Even though the regulations might look at the overall condition of the deck as being in good shape the severity of the one are would be a red flag for immediate action.

Gpr heat map

This is an image of a deck deterioration assessment of a bridge deck in-service for 76 years. The deck has 64% late-stage severe deterioration. This is a sample of a deck where early-stage deterioration was not detected and repaired. This deck is nearing its end of service life.

Roadway Inspection Using Infraspect’s 12 Levels Of Deterioration

Infraspect’s condition assessment report using GPR is the most detailed condition assessment of a bridge deck and slab available today. These inspections are in accordance with and exceed ASTM D-6087-8 and AASTHO Standards. Infraspect is the only company showing 12 levels of deterioration and conducting bridge inspections with expert certified bridge inspectors.

Bridge approach deck assessment
Color-legend
Gpr map showing levels of deterioration

The radar images above allow an experienced bride inspector trained in GPR to provide the department of transportation with a detailed assessment of the bridge deck or bridge deck approach way. If you have specific questions or scope of work that you would like to discuss you can submit them here.

Bridge inspection

Roadway Inspections with GPR

Infraspect’s GPR Inspections eliminate the need for lane closures or subjective inspections providing the department of transportation with the data they need to make infrastructure critical decisions.

Measures pavement thickness at highway speeds, and evaluates base and sub-base surfaces with actionable items. In just one day, Infraspect can assess hundreds of miles of pavement thickness. In addition, Infraspect can locate voids below the road surface and any concrete structure.

Good Road Scan

This is what primary and secondary reinforcement mats look like in a bridge deck without deterioration/delamination.

Ground penetrating radar image top mat
Ground penetrating radar

Bad Road Scan

This is what deterioration/delamination looks like when it reaches the top reinforcing mat.

Concrete Scanning with GPR can:

Locate rebar and post tension tendons within concrete.
Complete parking garage assessments.
Locate electrical conduits within concrete.
Locate voids hidden beneath concrete.

Ensure the structural integrity of your structure by allowing Infraspect to properly detect post-tension tendons and electrical conduits as well as assess the strength and health of the concrete structure. In addition, prevent costly accidents during construction or rehabilitation by knowing where to drill without the risk of hitting a post-tension cable or rebar.

Ground penetrating radar on sea wall
Pipeline inspections

Utility and Pipeline Inspections

Underground utility and pipeline locating and mapping are made easy with Infraspect’s GPR tuned to locate underground utilities. Some of the applications include electrical, steam, water lines, communications, gas oil, sewer, storm pipe inspections, and more.

Infraspect’s GPR assessments can help provide the qualitative data that engineers and asset managers need to make immediate repairs to ensure the public’s safety as well as extend the life of their assets

Assignment Examples

Infraspect's GPR can help create full design plans or as-built drawings for the purpose of performing load rating analysis. It utilizes NDT methods to identify voids, deck deterioration, rebar patterns, rebar sizing, and spacing.
GPR provides void detection inspection behind abutment wall to 20 feet out from a back wall.
Scanning with GPR helps create a plan view condition map of a parking garage deck. Locate subsurface defects including moisture intrusion map as well as locate deterioration and delamination.
GPR provides condition assessment of a bridge deck and approach way using NDT technologies.
Infraspect's GPR service provide condition assessment of a dock including post-tension cables, load rating of the deck for containers, and inspect the integrity of the sea wall.
Use GPR to locate underground utilities.
GPR service provides a condition assessment of a concrete pad for NASA.