Breakthrough celebrations overshadowed by money worries - TunnelTalk
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Breakthrough overshadowed by money worries Feb 2009
Paula Wallis, Reporter
Celebration over the successful completion of the tunneling contract for a light rail link under Pittsburgh’s Allegheny River to the North Shore has been replaced by fears of a total work shut down.
Fig 1

Final breakthrough of tunnel drives

Without an infusion of cash from President Obama’s $787 billion stimulus package, the Port Authority of Allegheny County announced work will stop on the North Shore Connector Project.
“There’s been a 36% increase in construction materials [prices] that was out of our control,” said Steve Bland for the Port Authority. “That has added $118 million or about 27% to the project’s over all cost of $435 million.”
Bland said the transit agency first realized the seriousness of the situation last spring when the new Gateway Station came in nearly 100% over budget, and two other bids for essential project work came in more than 50% and 100% over budget.
The announcement came just one week after the Authority celebrated on budget and on time completion of the $156.5 million tunneling contract - a note worthy feat given the complexity of the project.
“Mining two tunnels in a tight urban setting was a complex task to say the least,” said Port Authority Rail Operations and Engineering Officer Winston Simmonds. “The crews that worked on this project are to be commended for safely reaching this milestone on time and on budget.“
North Shore Constructors, a joint venture of Obayashi Corporation and local partner Trumbull Corporation, won the contract to extend the city’s ‘T’ light rail line from downtown Pittsburgh and under the Allegheny River to the North Shore July 2006.
Fig 1

Alignment to the North Shore

A 500-ton Herrenkneckt slurry machine excavated the 1.2km long twin tubes. After completing the first tube in about six months, in July 2008, the 6.5m diameter TBM started excavating the second tunnel in October 2008. Progressing an average of about a 10m/day, it worked its way from the launch pit located under Stanwix Street in downtown Pittsburgh, beneath Fort Duquesne Boulevard and the Tenth Street Bypass, under the Allegheny River, and ended its mission at the reception shaft located directly adjacent to the PNC Park football stadium.
Crews will now spend the next few weeks maneuvering the TBM out of the tunnel and its disassembly. Under a buy-back clause, the machine will returned to Herrenknecht for refurbishment and resale to a new project.
Meanwhile a new underground station at Pittsburgh’s North Shore, designed by New York architects Cooper and Carry, is taking shape. The concrete shell of the station, located underneath the Sports and Exhibition Authority parking garage, is nearly complete. Platforms are located about 12m below street level and the cut-and-cover structure will feature a vaulted ceiling.
“The station will have a rough-hewn finish as you ride the escalator from the concourse level,” said Jerry Marinzel, Project Manager for the Port Authority. “As you proceed to the platform level, the station transitions to a clean, smooth finish, giving passengers a sense of arrival.”
Excavation will soon begin on the Gateway Subway station under Stanwix Street. Crews will dig 10m below ground and advance approximately 107m of cut-and-cover work from the TBM launch pit back to the site of the new station.
Fig 1

Cut-and-cover transition with the surface

The funding crisis is one more in a list of obstacles that the project has overcome. An initial construction start date of August 2005 was set back when bids for this first and largest contract on the project, the tunneling contract, came in much higher than the engineer’s estimate. The Obayashi-Trumbull bid of $156.5 million for the current contract was substantially higher than its earlier bid of $119.8 million for the tunnels alone.The second bid included construction of 1,200ft (365m) of alignment on the North Shore and the shell of the North Side Station.
Transit officials say the project meets all the necessary requirements for Obama’s stimulus package money and are hopeful federal funding will rescue the project. They say borrowing the necessary funds would mean 48 -55% of the Authority’s available capital would go to servicing debt, severely compromising maintenance of the core infrastructure.
Other options being considered include delaying the project at a cost of about $3 million a month, or moth-balling the project at a cost of $290 million already spent and another $20 million to secure the sites. These are the least desirable options in that they would severely hurt Pittsburgh’s chances of securing federal funding for future transit projects, regardless of their merit.
Weblinks
Port Authority of Allegheny County
Herrenknecht AG
Obayashi Corporation
Trumbull Corporation
Cooper Carry Architects

     

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