Big Dig lawsuit blames contractors for structural damage

Boston’s Big Dig project, which buried 10 lanes of highway beneath the city, could have caused considerable structural damage to historic buildings near the harbor.

According to a lawsuit that was filed earlier this month, construction work on Big Dig tunnels might have lowered the water table on the South Boston waterfront, triggering rot in wood pilings that support many of the old industrial buildings in the area. Contractors who worked on the project were recently named in the lawsuit, along with the Massachusetts Turnpike Authority and the MBTA Silver Line.

Specifically, the lawsuit alleges that when contractors built the Interstate-90 extension to the Ted Williams Tunnel, the water table fell so much the area was “dewatered,” which exposed the piles to rot. It is not known how low the pilings have been exposed.

In areas close to the harbor, buildings rest on wood pilings that are pressed deep into the earth. The pilings are preserved from rot because they are supposed to be submerged in water. When the water lowers, however, the wood begins to deteriorate and severe structural damage can occur.

The MBTA, Turnpike Authority and contractors have denied responsibility for the decay, which became a major issue in late 2003, when Tishman Speyer of New York planned to purchase four dozen of the industrial buildings from Boston Wharf Co. He pulled out of the $400 million deal because of the risk of structural damage. In recent years, the buildings have become popular as residential lofts.

Boston Wharf filed a previous suit in 2002, saying it had spent $100,000 for consultants and tests to find out the extent of the rot problem.