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Mass Turnpike Big Dig leakage rate increasing despite attempt to fix - Boston Globe
Posted on Sun, 2007-07-01 14:35
The main I-93 "Thomas O'Neill" Tunnel of the Big Dig in Boston is leaking about fifty times the contracted limit for water seepage and the volumes are going up - the Boston Post reports today.
An average 50 gallons per hour (190L/hr) is the limit specified in contract documents for the allowed leakage in the 2400m (1.5mi) long tunnel constructed by cut and cover under the streets of central Boston.
During the first quarter of this year 2,600 gallons/hour (9840L/hr) average were leaking - 52 times the contract allowed limit. In 2005 the flow was 2,200 gals/hr (8327L/hr) in the same first three months.
The Massachusetts Turnpike which manages the tunnel - even though it is untolled - stopped posting leakage numbers on their website, but the Boston Globe got the numbers from the state water resources authority.
In November 2004 project managers Bechtel/Parsons Brinckerhoff said the program to seal leaks would be completed "within months" but it is obviously far from done 32 months later.
The Turnpike says the number of leaks in the O'Neill has been reduced from 3,500 in 2004 to 800 and about $5m/yr is being spent on leak plug efforts. Trouble is as leaks are plugged remaining leaks leak more and old patches open up again.
Leaking water is being pumped into the Boston sewer system. The Turnpike has so far not been abler to get permits to dispose of the water in Boston harbor.
The problem was dramatized in September 2004 when several square feet of supposed concrete walling turned out to be mostly loose stones and mud and a gusher overwhelmed pumps. Ponding water forced lane closures. Investigations found slurry wall construction and seals had been shoddily built and identified 3,5000 points where repairs were needed.
The Turnpike is in court pursuing claims against project manager Bechtel/Parsons Brinckerhoff and building contractors for damages, negligence and breach of contract.
TOLLROADSnews 2007-07-01
An average 50 gallons per hour (190L/hr) is the limit specified in contract documents for the allowed leakage in the 2400m (1.5mi) long tunnel constructed by cut and cover under the streets of central Boston.
During the first quarter of this year 2,600 gallons/hour (9840L/hr) average were leaking - 52 times the contract allowed limit. In 2005 the flow was 2,200 gals/hr (8327L/hr) in the same first three months.
The Massachusetts Turnpike which manages the tunnel - even though it is untolled - stopped posting leakage numbers on their website, but the Boston Globe got the numbers from the state water resources authority.In November 2004 project managers Bechtel/Parsons Brinckerhoff said the program to seal leaks would be completed "within months" but it is obviously far from done 32 months later.
The Turnpike says the number of leaks in the O'Neill has been reduced from 3,500 in 2004 to 800 and about $5m/yr is being spent on leak plug efforts. Trouble is as leaks are plugged remaining leaks leak more and old patches open up again.
Leaking water is being pumped into the Boston sewer system. The Turnpike has so far not been abler to get permits to dispose of the water in Boston harbor.
The problem was dramatized in September 2004 when several square feet of supposed concrete walling turned out to be mostly loose stones and mud and a gusher overwhelmed pumps. Ponding water forced lane closures. Investigations found slurry wall construction and seals had been shoddily built and identified 3,5000 points where repairs were needed.
The Turnpike is in court pursuing claims against project manager Bechtel/Parsons Brinckerhoff and building contractors for damages, negligence and breach of contract.
TOLLROADSnews 2007-07-01
