Engineers Use Underground Radar to Locate Post-Katrina Damage

Ultra-wide band pulsed radar enables inspection of underground infrastructure.

Underground pipe inspection vehicle uses ultra-wide band (UWB) pulsed radar technology developed at Louisiana Tech University to detect fractures, quantify corrosion and determine the presence of voids in the surrounding soil. (Image courtesy of Louisiana Tech University.)

Underground pipe inspection vehicle uses ultra-wide band (UWB) pulsed radar technology developed at Louisiana Tech University to detect fractures, quantify corrosion and determine the presence of voids in the surrounding soil. (Image courtesy of Louisiana Tech University.)

An innovative underground radar technology is helping the city of Slidell, Louisiana identify and document underground infrastructure damage that had gone undetected in the months and years following Hurricane Katrina.

This radar technology is a pipe-penetrating scanning system based on a new technology called ultra-wide band (UWB) pulsed radar. UWB allows for the inspection of buried pipelines, tunnels and culverts to detect fractures, quantify corrosion and determine the presence of voids in the surrounding soil often caused by water leaks and flooding.

Developed at Louisiana Tech University’s Trenchless Technology Center, UWB incorporates simulation, electronics, robotics, signal processing and three-dimensional (3-D) renderings in a package that can be mounted on existing pipe-inspection robots.

Arun Jaganathan, associate professor of civil engineering and construction engineering technology at Louisiana Tech, began developing this technology as the basis for his Ph.D. dissertation research. Partnering with fellow Louisiana Tech researcher Neven Simicevic and others, his vision was to eventually develop it into a tool that municipal engineers can use for their routine pipeline condition assessment.

“Our UWB technology was based on recognizing the need within the trenchless industry for an advanced pipeline inspection tool that can quantify the structural integrity of buried municipal pipes like sewers and storm drains, and be able to see through the pipe wall,” said Jaganathan.

“The radar system emits ultra-short electromagnetic pulses from inside of a sewer pipe and captures the signals ‘back-scattered’ from the pipe to determine the condition of various layers hidden behind the wall which we cannot directly see using visual tools such as a camera,” Jaganathan explained. “The radar is integrated into a robot which crawls through a pipe and relays the data back to the operator in real time.”

Following successful testing and development, Jaganathan and other researchers came to Slidell in the summer of 2013 to pinpoint the spots in the city that would be most beneficial for using the UWB, and to test and investigate the underground infrastructure issues.

As had been predicted by the group in their initial research, compromised infrastructure was able to be seen using the UWB technology and, most importantly, became provable.

“While we were aware of the depth and breadth of the problems that plagued our underground utilities and we knew surrounding communities had experienced similar problems, I believe it wasn’t until we made the trip to Ruston in 2010 and then saw the results of the UWB investigation that we actually realized we could have quantifiable evidence of the scope of that damage,” said Slidell city council member Jay Newcomb.

As a result of the work of Jaganathan, Simicevic and the Louisiana Tech researcher team, and consultations with other engineering firms, the City of Slidell was able to secure $75 million in funding from FEMA to begin the underground utility restoration process.

“This technology is unique in its capability to generate high resolution images which allow engineers to inspect a particular spot in detail,” Jaganathan said. “Unlike many other radars, our system does have to be in contact with the pipe wall and this provides capability for rapid inspection to finish scanning a long pipe in a timely manner.”

For more on developments in modern infrastructure, read about testing earthquake-proof water pipelines.