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Conditions BOSTON
MAJOR HIGHWAYS
CAPE COD
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Delays pushed tunnel opening back By Boston.com Staff
In 1994, before construction had even begun, the project was rocked by revelations published in the Globe that engineers had failed to test the soil properly before designing the new tunnel. The area around the Fort Point Channel, like much of modern Boston, was created in the 19th century by landfill dumped on tidelands. The mushy, unstable soil, compared by one Big Dig official to "old pudding," meant that the original design for the crossing was virtually unbuildable. In mid-1994, construction plans had to be rethought from scratch. The new design, employing a novel technique known as "tunnel jacking" (see the construction page), added $200 million to the project's cost but, engineers promised, would shave off a year of construction time, allowing the new tunnel to open in late 2001. Once again, however, things would not go according to plan. In July 2001, a leak sprang in one of the huge concrete tunnel segments resting on the floor of the Fort Point Channel. For a time, up to 50,000 gallons of seawater per minute poured through the gap, flooding the tunnel and submerging construction equipment inside. It took engineers three months to repair the leak and pump the tunnel dry, at a cost of between $5 million and $10 million. Because delays in one part of the project impact progress elsewhere, the true cost of the delay was much higher. In December 2002, the Massachusetts Turnpike Authority reached a $34 million settlement with contractor Modern Continental over the troubled tunnel segment. A Globe review of internal state documents later revealed that a Big Dig design firm had warned project managers in 1999 that a series of last-minute construction changes to the channel tunnel could lead to water leaks. The warnings apparently went unheeded by engineering consortium Bechtel/Parsons Brinckerhoff, which oversees the project. In March 2002, the Big Dig announced a revised opening date of Oct. 25 for the Turnpike extension. That date was later pushed back to mid-December, and finally to late January 2003 as delays cropped up in the installation of the Integrated Project Control System, a network of video cameras, traffic-flow sensors, carbon monoxide gauges, and electronic signage that will allow workers at the Big Dig's South Boston control center to monitor traffic in the tunnels and respond to accidents and other emergencies. Concerns also developed over the ability of the high-tech highway monitoring system to detect tunnel fires. In May 2002, heat sensors inside the Ted Williams Tunnel failed to go off when a bus carrying the Seattle Mariners baseball team caught fire inside the tunnel. In August, the Boston Fire Department granted the Big Dig's request to scrap the fire-detection system and instead focus resources on fire-extinguishing equipment. The delays on the Fort Point Channel crossing have cost the Big Dig valuable time elsewhere, pushing back the opening dates for the northbound and southbound lanes of the Central Artery tunnel. According to the latest project schedule, the northbound I-93 tunnel is set to open in February, with the southbound side following a year later. As Boston drivers have learned from past experience, those dates are subject to change. Story based on information from the Globe and the Central Artery/Tunnel project |
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