The Big Dig has left a 2½-mile trail of cracked walls, shifting foundations, and flooded basements through the heart of the city, from North Station to the South End, property owners there say.
As the project rolls toward completion in September, more than 100 owners, residents, and businesses have filed complaints or insurance claims that could total tens of millions of dollars for everything from water damage in private homes to rotting pilings supporting historic buildings.
Most say they have received little help from Big Dig managers, or the project's insurer, which routinely dismisses most damage claims. Many homeowners said insurance adjusters visit their homes, offer reassuring words, then send a letter denying their claims.
''My son was in bed, and the ceiling cracked open in the middle," said Josephine Spagnuolo, who said wall and ceiling cracks started to appear in her renovated North End house soon after Big Dig crews began excavating beneath the Central Artery in the late 1990s. The building shook nightly, she said, and the cracks got worse until one night, when the vibrations were particularly strong, the ceiling split open. When she complained to Big Dig authorities, she said, they installed meters to measure the cracks.
''They'd come up and look and say, 'No, it wasn't us.' "
With the end of the project in sight, and deadlines for lawsuits approaching, many property owners are hiring engineers to assess the damage and lawyers to build cases. While some still hope to negotiate directly with Big Dig managers, others have given up and are headed to court.
The artist owners of 249 A St. in South Boston say they were left with no choice but to sue after the Big Dig's insurance adjusters and engineers denied responsibility for damage they say has undermined their 100-year-old building.
The owners say they have paid to repair exterior cracks around windows and doors. But they believe construction on the nearby Ted Williams Tunnel caused additional damage -- the rotting of wood piles that support the 1895 building. They say it will cost more than $1 million to fix.
''If we don't make the repairs, the building would eventually collapse," said Michael Roitman, lawyer for the owners.
Big Dig officials said that legitimate claims will be paid but that the project and its insurers, AIG, have an obligation to protect taxpayers from frivolous claims.
''If property owners observe what they think is damage, if it's the result of the artery tunnel project, or if there's a reasonable chance it's the result, we'll work with the property owner," said project director Michael Lewis. ''If we cannot make a causal link, we'll have to say we see no causal link and therefore can't pay for damage to the building, which we think is the result of either lack of maintenance or other causes."
He said project managers took precautions to prevent damage that included modifying construction techniques near vulnerable buildings, shoring up some buildings to protect them, and installing seismographs and other instruments to monitor the project's effects on some nearby structures.
Still, according to engineers interviewed by the Globe, damage was all but inevitable. As tons of heavy machinery pounded at the earth to dig miles of tunnels, vibrations traveled underground, shaking structures along the construction route. In several places, ground water was drained in the course of construction, which can cause wood pilings to deteriorate or settle. And the removal of millions of cubic yards of earth could have caused slight movements in the soil around houses and buildings, shifting stone foundations.
Even minute changes could put structures under stress, causing problems like cracks in walls, separated joints between walls and ceilings, or broken windows, the engineers said.
''All of a sudden you have something disturbing the natural soil," said Craig Barnes of CBI Consultants Inc. in Boston. ''We're not talking about huge movements. Soil is moved, and adjacent structures are affected."
Some public officials said the Big Dig has been too reluctant to take responsibility for damage along the construction route.
''I know they haven't been [paid], and I know they should be," said Salvatore F. DiMasi, speaker of the Massachusetts House, referring to property owners who have filed claims. ''I'm not an expert. I'm not an engineer. But I believe these people have a reasonable expectation for compensation based on the evidence that has been produced. I've seen some of it myself -- the cracks, the basements where the walls were cracking, the foundations that appear to have shifted. I'm not an expert, but they dig 100 feet away or less and go down 45 feet with pile drivers and they say the damage wasn't created by them? It's not logical."
According to documents provided by the Big Dig following an open-records request, more than 100 property owners have filed claims since 2000. Fewer than 20 have received compensation. The Big Dig has paid out $365,532 in claims, a number that includes construction accidents and expenses incurred by the insurance company's adjusters, according to Tom Welgoss, the Big Dig's director of risk management. Officials would not say exactly how much went to property owners.
After eliminating claims of minor damage or onetime construction accidents, the Globe found about 80 property owners on the list who reported serious problems, including shifted and damaged foundations and cracked walls and ceilings. They included buildings large and small, from South Station, Russia Wharf, One Financial Center, and the Federal Reserve Bank to dozens of homes. The list includes 200-year-old buildings and some modern high-rises.
Big Dig officials knew before construction began that there was the potential for damaging nearby buildings. In 1988, consultants hired by the Big Dig examined 284 historic buildings near the construction path and rated them according to their potential for damage from vibrations, soil movements, and dewatering. The Big Dig also visited buildings near the project to assess their vulnerability and take steps to strengthen those they considered to be most at risk. Managers said they shored up about 20 buildings. Big Dig workers also videotaped many nearby buildings inside and out to document damage before construction.
But the measures have given no guarantees to some residents who say damage developed after construction began. Nancy Caruso, a North End activist and retired Northeastern professor who helped win community support for the project in the 1980s, said her damage claim was rejected even though a recent videotape of her living room wall shows a deep crack that did not exist on preconstruction videotapes taken by Big Dig officials.
Sal Tecce, owner of Tecce's Restaurant, alleges construction caused the foundation of several attached buildings his family owns to move 2 inches, causing severe structural problems. In the preconstruction survey of historic buildings, his property was cited as having a high potential for damage.
''Construction was 14 feet from my building," said Tecce, who has hired a lawyer and an engineer. ''The floors are starting to pitch, and the roof leaks. There are also large cracks in the walls upstairs."
Some of the Big Dig's efforts at monitoring were little more than maddening to some who made claims. Kate Brill-Daley, manager of the Clubs at Charles River Park, complained about damaging vibrations in 2004, about a year after AIG sent a letter denying ''a causal relationship" between construction vibrations and the cracks that developed on a concrete deck around the pool. She recalled that when project surveyors arrived to determine whether the strength of the vibrations exceeded acceptable levels, they told her that they could not read their instruments. The vibrations were too strong, she said they told her, and they would have to wait until the work stopped. ''It was so bad you were afraid the windows would crash in and glass shelves would fall," she said.
Closer to downtown, Francis R. Croken, general manager of the Harborside Inn on State Street, said the former 1800s warehouse was meticulously restored before it was converted to a small hotel in 1997.
About three years later, when the Big Dig's pile drivers began tearing up the earth outside, he said, cracks formed on the interior brick walls, including one that stretches for four stories in the hotel's atrium. The Big Dig denied responsibility.
''Bricks shook loose from the violent drilling, bricks that had all just been remortared," he said. ''It bothers me. They turn around and say, 'The building is old.' They try to use it against you."
Not all property owners have been turned away by the Big Dig. Some who were initially rejected by the project's insurance company said they are negotiating financial settlements with Big Dig officials.
A group of homeowners on Commercial Street, who say their basements have sunk, causing gaps and cracks in other parts of the buildings, are trying to work out a deal.
One building in the block, at 90 Commercial, is not participating, electing instead to file a lawsuit alleging $250,000 in damage.
''The insurance company denied their claim, but we worked with them," said Big Dig associate project director Stephen Collins. ''We looked at it again. We determined that although the contractor was not negligent, there was a good chance that construction caused some damage to those properties."
But some property owners said they have neither the financial resources to file a suit nor the emotional energy to invest in a negotiating process that could take months, with uncertain results.
Phyllis Notaro of the North End said she consulted a lawyer, who recommended that she put her money into building repairs, not legal fees.
Globe correspondent Chris Berdik contributed to this story.