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Big Dig engineers find new wall flaw

Big Dig engineers found a serious flaw this week in a section of Interstate 93 tunnel wall that is similar to the defective wall where a gushing leak erupted Sept. 15, Turnpike Authority officials announced yesterday.

The flaw was discovered Tuesday as part of an ongoing investigation into whether the September leak was an isolated occurrence or part of a wider problem with the walls that form the backbone of the $14.6 billion tunnel network.

At a press conference, Turnpike Authority officials cautioned that the flawed wall panel discovered Tuesday is not leaking nearly as much water as the one in September, which flooded the northbound tunnel and caused a 10-mile traffic jam. But the defect is still considered extremely serious, said Matthew J. Amorello, chairman of the Massachusetts Turnpike Authority, which oversees the project.

''I am as upset at this as I was when the first panel breached," Amorello said.

''The first panel was unacceptable; the second panel is unacceptable," he said during a press conference. ''The investigation will continue, and we will address all of these matters. And the responsible parties will be held accountable."

Turnpike Authority officials acknowledged last month that there are hundreds of leaks riddling the Big Dig tunnel system, but they say they believe that most are located at tunnel joints or along the seam where the tunnel walls meet the roof and can be repaired through patching with grout injections.

However, the problem discovered Tuesday, like the September breach, is of deeper concern, because it is the result of a weakness in what is supposed to be a solid, 3-foot-thick tunnel wall.

''We are concerned because [the wall] is weeping," Keith Sibley, Big Dig program manager for Bechtel/Parsons Brinckerhoff, said, describing the leak.

In addition, repair of such a problem is far more complicated, could take months, cost hundreds of thousands of dollars, and may require the replacement of large sections of wall.

Sibley agreed with Amorello that the newest leak is a major concern, but insisted it is too early to speculate about an extensive problem with tunnel walls.

''We are just starting, and I would suggest [that] to draw any trending conclusions at this point is very premature," Sibley said.

Still, Amorello said he expected discovery of more defective panels. ''We will probably find something more," he said.

Since Sept. 15, engineers with Bechtel/Parsons Brinckerhoff, the Big Dig's private-sector managers, as well as independent specialists hired by the Turnpike Authority, have identified seven wall panels, each about 20 feet long, that appear to contain pockets of gravel or other extraneous material, even though the walls are supposed to be solid concrete. However, six of the seven have not sprung leaks.

There are several thousand panels in the tunnels, and so far the engineers have examined 40, and plan to scrutinize 200, selected because they are similar in design to the one that leaked in September.

Two of the engineers hired by the Turnpike Authority, George J. Tamaro and Jack Lemley, testified on Beacon Hill Tuesday that the cost of repairing the September leak will run as high as $500,000, take up to two months, and require closing one or two traffic lanes at night.

At yesterday's press conference, Michael P. Lewis, the Turnpike Authority's Big Dig project director, said the repair will involve ripping away the concrete, inserting new steel support beams, and replacing the extaneous material with solid concrete.

Big Dig officials, Amorello, and the independent engineers all agree that the tunnel is structurally sound and safe to drive in. But the problem with the leaks has become a focus of frustration and has prompted fears over how extensive and lengthy repairs will be.

Today, the Legislature's Joint Transportation Committee is to conduct a second day of hearings on the leaks.

Scheduled to testify are Amorello; a representative of Bechtel/Parsons Brinckerhoff; Amorello's cost-recovery team leader, Edward M. Ginsburg; and a top official in the US Department of Transportation's Office of Inspector General.

Yesterday, state Senator Mark C. Montigny, a New Bedford Democrat who has frequently blasted the Big Dig for waste and mismanagement, filed legislation to establish an oversight commission to ''investigate and estimate" the amount of taxpayer money lost ''due to problems such as leaks."

The commission would also investigate the work of the Turnpike Authority's cost-recovery legal team, which Amorello assembled in January 2003 to recoup money lost to mismanagement or shabby construction work.

To date, that team has filed roughly a dozen lawsuits against Big Dig design firms and recouped $3.5 million from an out-of-court settlement.

In 2003, Governor Mitt Romney signed a bill that extended the statute of limitations for pursuing contractors and engineers for negligence and errors on the project.

Other lawmakers are considering proposals similar to Montigny's. Senate Transportation Committee chairman Steven A. Baddour, a Methuen Democrat, said he may file legislation that would hand over cost-recovery responsibilities to the attorney general's office.

Senator Marc R. Pacheco, a Taunton Democrat who chairs the Post Audit and Oversight Committee, has proposed an independent cost recovery body that would not only oversee efforts to recoup money on the Big Dig, but also propose sweeping changes to the way state construction projects are managed.

Washington lawmakers may also have a say in the process, not least because the Federal Highway Administration has pumped $8.5 billion into the Big Dig. In January, the US House Government Reform Committee will hold a hearings on the leaks.

Murphy can be reached at smurphy@globe, Lewis at rlewis@globe.com.

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