Aging pier footings pass safety tests for Dulles Metrorail Project
Friday, July 2, 2010
Safety tests on aging foundations that will be used to support a bridge carrying Metrorail trains over Interstate 66 have verified that the footings are structurally sound, officials with the Dulles Metrorail Project said Thursday.
The tests were mandated last year by the Federal Transit Administration, which questioned a safety testing plan proposed by the contractor building the first 11.5 miles of the rail extension to Dulles International Airport.
Dulles Transit Partners had proposed to test two of the 11 pier foundations that engineers designing the flyover had discovered buried up to 50 feet under I-66 and the Orange Line tracks. The footings were hammered underground by the Virginia Department of Transportation 33 years ago for a possible subway line to the airport. Historical drawings that would show detail of the structures were lost.
The FTA ordered extensive load-bearing tests on every foundation -- including reevaluation of the two already tested -- after criticizing the Metropolitian Washington Airports Authority, overseeing construction of the rail line, of lax oversight of the project.
On Thursday, Patrick Nowakowski, executive director of the Dulles Corridor Metrorail Project, said the tests showed the foundations to be "in excellent shape."
"It's very good news," Nowakowski said. "We didn't have to do any strengthening" of the structures by adding additional steel pilings inside the concrete. The results have been sent to the FTA for a final sign-off. "Then we can move ahead," Nowakowski said. The government is paying $900 million of the $2.6 billion cost of the rail line's first leg.
The tests required Metro to partially shut down service on the Orange Line during three consecutive weekends in May and June so workers could reach three foundations with limited access. The first leg will start just beyond the East Falls Church Metro station and end at Wiehle Avenue in Reston.
Safety concerns about the limited tests that had been planned were first raised by the project's former bridge manager, Steve T. Mackey, last year and reported by The Washington Post last fall. Mackey said he urged more load-bearing tests but was overruled.
Nowakowski said he did not know how much the testing cost because Dulles Transit Partners, which is paying the fee, is still waiting for some bills. He declined to provide an estimate.
Since the foundations were discovered after the project was designed with new footings, the money saved from using the old ones will cover most of the testing costs, Nowakowski said. "We expect things to about break even."