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Researchers combat infrastructure decay

January 25th, 2009 | © (2009),The Ruston Daily Leader | Related Directory Content

Nick Todaro, Reporter
01-25-2009

In November 2007, a hole big enough to upend a car or swallow a person opened up in Trenton Street in downtown Ruston.

Richard Aillet, the city’s water utilities director, explained the problem was a sewer line break gone wrong. The break allowed dirt surrounding the buried pipe to wash into the utility line and away through the city’s sewage treatment system.

That dirt eroded over an unknown period, leading to a void around the pipe. All it took was enough time and enough pressure, maybe a heavy log truck loaded just so, and the area next to the manhole at the corner of Trenton Street and Alabama Avenue gave way. The void was five feet deep and three feet across.

“It caved in one day before we planned to bring the television truck out to examine it,” Aillet said the day after the event.

He said the city’s sewer system, aged in some areas to its expected 50-year maximum life and as much as 20 years beyond that in some places, suffers similar incidents about twice a year, but the city continues to fight the problem. With 136 miles of pipe, it would take seven years to inspect all of it at the current rate, he said.

Ruston is not alone in the problem, said Louisiana Tech researcher Erez Allouche, who is leading a project working on an innovative technology addressing the problem.

Reports show an epidemic of sinkholes forming from New Orleans to New York and in places around the world, he said. Research shows infrastructure has gone an entire generation without maintenance in some places.

FutureScan, a Tech project and concept a handful of years old, is aimed at preventing sinkholes before they start.

Doing so effectively involves a robot and a new scanning technology capable of producing high-resolution images of the exterior of pipe walls. It is an improvement over current technology, which cannot reliably detect the voids, Allouche said.

The process: a robot tracks along the inside of the pipe carrying a sensor capable of short, pulsed radar signals. The signal pulses so fast that light would travel mere centimeters in between pulses, Allouche said.

Those pulses are bounced in narrow beams aimed around the pipe.
The process is capable of producing high-resolution images that show potentially dangerous areas where dirt has washed away.

“This is extremely, extremely fast,” Allouche said of the radar technology.

“The nature of the pulses gives us a resolution to a couple of centimeters, and we hope to soon refine that to millimeters,” he said. “This technology is absolutely unique. It’s not cutting edge; it’s bleeding edge.”

The nation’s biggest manufacturer of robotic inspection equipment has taken note, Allouche said.

Cues, an Orlando, Fla.-based firm, is working with Allouche and the team of Tech researchers responsible for the FutureScan project in an effort to further develop the technology.

Void detection is a technology unique to the team, made up of Allouche, and faculty members Arun Jaganathan, Neven Simicevic and Klaus Grimm.

The team has set up concrete, clay and plastic pipes at the university’s Trenchless Technology Center, with void “targets,” testing the accuracy of the equipment prototypes they have developed.

The data that tests at the TTC have produced are so large that the Louisiana Optical Network Initiative supercomputer cluster is performing necessary analysis, Allouche said.

A startup company formed around the technology called Beyond Vision is also nestled in Tech’s business incubators.

The team has been awarded one of nine Technology Innovation Program grants from the National Institute of Standards and Technology for their work, securing about $3.2 million for work with industry partners.

About $900,000 of that is flowing to Tech in the next three years, funding 13 full-time engineering faculty positions, including some at Beyond Vision and technical staff for the TTC.

“That is substantial research and development capacity,” Allouche said.

Aillet is enthusiastic about the project.

He said once the team’s research and development effort has matured enough that they are ready to field test it, he’s open to using the detection technology on Ruston’s pipelines.

“I’ve got some pipes that are ready for them,” he said.

All of this technological advancement makes the process of finding the voids before they become lethal liabilities for the governments watching over the infrastructure that much easier.

After discovery, Allouche said, it’s as simple as grouting a void to fill it in and keep an area structurally sound.

“When you’re driving over a road, you’re not going to expect it to cave in underneath you,” Allouche said. “And there is an expectation out there that our pipes, roads and bridges will never fail. But we’re doing very little to ensure that. Our infrastructure systems have a limited life. It could be a bus full of kids or a big truck that is sucked under.”