Seeing under streets before digging

Tryout: A Washington company shows its stuff by showing what lies beneath a stretch of Lombard Street.

April 26, 2001|By Andrew Ratner | Andrew Ratner,SUN STAFF

Witten Technologies' radar-enhanced imaging has searched for Captain Kidd's ship in the Indian Ocean, helped solve the mystery of rolling blackouts in New York City and combed beneath San Diego to find a suitable site for a new baseball stadium.

The Washington-based company was in Baltimore this week hoping to land a new job: mapping miles of underground downtown to assist a two-year, $30 million project to bury high-speed fiber-optic cable.

Companies developing the Baltimore project, known as Harborlink, asked Witten for a demonstration of what it calls computer-assisted radar tomography, or CART. A Witten official described it as a "CAT scan for the street."

Cities have been wrestling with the problem of how to provide high-speed fiber-optic lines to accommodate businesses that need quick connections to the Internet without repeatedly tearing up their streets to do it. There's also the problem of accidentally hitting underground utility lines - injuring workers or knocking out power to the central business district. Relying on old utility maps has proved frustrating.

"The old maps are maybe 65 percent accurate, but the 35 percent left can kill you," said Carmine Lamberti, project manager for White Marsh-based LAI Construction Services Inc., general contractor for the Harborlink project. "You're talking about someone's life. Plus, the cost to have BGE repair a broken line can be tens of thousands of dollars. It can eat up all your profit on a project."

Harborlink has not received final city approval. A Towson lawyer representing the project, Jeff Riley, declined yesterday to comment on its status.

If Harborlink proceeds, the project will be one of the largest of its type ever, according to Witten President Robert Green.

An underground trench would be constructed for nearly 6 miles from the Inner Harbor north to Pennsylvania Station. Another would head southwest to the former Montgomery Ward warehouse that is being converted into the city's largest office building.

"If I have to dig along Lombard Street and tear up the street during baseball season and football games, I want the least disruption possible," said Felix Dialoiso, an LAI vice president. "We're working with drawings from the 1930s to tell us what's underground."

After a trial run Tuesday night in the shadow of the blue-lighted Bromo Seltzer Tower, Dialoiso said he was impressed. "I wasn't expecting all the detail," he said.

Representatives from Baltimore Gas and Electric Co. and Dewberry & Davis, a Fairfax, Va., architectural engineering firm, attended the demonstration.

Privately held Witten developed the ground-penetrating radar system with Schlumberger Ltd., based in New York and Paris. Radar has been used for decades to record two-dimensional images for excavation work, but new software adds a third dimension. The research, in development for the past three years, has financial backing from the Electric Power Research Institute, a nonprofit research arm of power companies based in Palo Alto, Calif., and the Gas Technology Institute, a similar research group of natural gas providers based in Chicago.

Several nights this week, Witten engineers drove a sport utility vehicle at a 2-mph crawl along several blocks of Lombard Street. The vehicle dragged a flat trailer topped with two strobe lights. Inside were 17 radar transmitters and receivers. A distance-measuring Geodimeter helped identify where the data was collected. The system was, in essence, snapping millions of pictures of what lies beneath Lombard Street. Computers converted the data into three-dimensional pictures, using color coding to indicate the depth of buried objects.

"It's similar to slices of a medical X-ray. When you put the slices together, it becomes a CAT scan," said Warren Getler, executive vice president of business development for Witten. "That is what we do underground."

Geophysicist Alan Witten used his research in tomography a decade ago to help the Pentagon detect tunnels that North Korea had burrowed beneath the Demilitarized Zone along South Korea. and to help paleontologists in New Mexico locate and dig up an enormous fossil. Its name reflects his work: Seismosaurus. Author Michael Crichton developed the scene in "Jurassic Park" of paleontologists using seismology after reading of Witten's work.

Witten joined Green, a construction executive, in 1994 to develop a commercial application.

Since then, the Discovery Channel used the technology last summer to locate wreckage of a sunken ship reputed to belong to the fleet of the 17th-century pirate Captain Kidd off the coast of Madagascar.

Consolidated Edison, the New York power company, hired Witten last winter to create a 3-D map of parts of the city. It detected abandoned, buried trolley tracks that kept bumping and shorting out underground transmission lines.

Witten officials said they consider the Baltimore project key as they seek to demonstrate applications of their technology to attract investors.

Engineers were impressed by a test several weeks ago when Witten radar detected a concrete box underground, possibly a footing for a fixture of the old trolley system. When a backhoe opened the street, they found the square - just where the Witten map showed it, Dialoiso said.

"The mayor said he wants to make this the digital city," said Lamberti, who joined LAI this year after 21 years with the Baltimore Department of Public Works.

"But you're talking about laying fiber in an underground system here since the 1900s. The original owners were the railroad companies. We're most interested in bare space. We're looking for space."

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