Extensive testing in new safety plan for Metro bridge
Friday, December 4, 2009
The regional airports authority has told the contractor building the Metrorail extension to Dulles International Airport to do safety tests on all of the 32-year-old foundations that will be used to support a bridge carrying trains over Interstate 66.
Dulles Transit Partners, which is building the first 11.7 miles of the Silver Line, also must retest two footings it certified as safe last year after the Federal Transit Administration questioned whether the contractor tested enough steel pilings within the structures, according to a letter submitted to the agency Thursday.
The revised testing plan comes 10 days after The Washington Post reported that the FTA had opened a safety inquiry into the Dulles Transit Partners testing plan, which had proposed to test only two of the 11 pier foundations that will support the flyover. Federal officials, who demanded a more rigorous testing plan, are concerned that the failure of any of the supports could cause a structural collapse that would endanger riders.
On Thursday, Patrick Nowakowski, executive director of the Dulles Corridor Metrorail Project, said the dispute over safety testing has evolved into a "public perception issue" and is "no longer an engineering issue." He said he would have been satisfied with load-bearing tests on fewer foundations, as long as the pilings were found to be secure. Tests on two foundations showed no problems.
When the tests are redone on the first two foundations, Dulles Transit Partners will test an additional piling in each, acting on the recommendation of a consultant to the FTA. "It exceeds what we normally do with piles," Nowakowski said.
"Assuming the rest of the testing that was planned came out okay, it would have been our belief that if the results came out as good as they did, some tests would have sufficed," Nowakowski said. "But we need to assure the public these things are safe. There's a certain fear that's been created."
The contractor had agreed last month to test nine foundations, but federal officials were not satisfied.
The Metropolitan Washington Airports Authority, which is overseeing the project, will require other measures "to ensure the integrity" of all of the foundations, the plan says, including inspections for rust and corrosion and tests to determine whether electrical currents from the existing Orange Line could have caused pilings to deteriorate, a concern of Metro officials.
It has not been determined how much the testing will cost, but Nowakowski said he expects Dulles Transit Partners to pay. "It's their responsibility," he said.
The contractor is a joint venture of Bechtel Infrastructure, the lead partner, and URS (formerly Washington Group International).
"We're glad there is a plan that appears to meet the requirements of all of the agencies, and we're anxious to get on with the work," said Dulles Transit Partners spokesman Howard N. Menaker.
Menaker said he was unsure whether the dispute will delay completion of the bridge, located near the start of the Silver Line at the East Falls Church Station. The first leg of the 23-mile Silver Line will stop at Wiehle Avenue in Reston.