An inspector generalís report released this past week criticized the Federal Transit Administrationís oversight of the Dulles Metrorail project, and raised new concerns about the adequacy of tests done on bridge pier foundations used for the new Silver Line.
While doing soil borings during the design phases of the rail project, engineers discovered 11 steel piles and pier foundations in the area where a bridge will branch off the existing Orange Line in Falls Church to the Silver Line, at the intersection of Interstate 66 and Va. 267. The foundations were installed more than 30 years ago, at the time the Orange Line was built.
Engineers with project contractor Dulles Transit Partners, under the oversight of the FTA, conducted testing in 2008 and 2010 and determined the old foundations could be used to support the piers of the new bridge, which will carry trains from the existing Orange Line over westbound I-66 to the median of the Dulles Airport Access Road.
With Silver Line construction about a year away from completion, the U.S. Department of Transportation Office of the Inspector General now is saying the FTA did not require the Metropolitan Washington Airports Authority and Dulles Transit Partners to perform enough testing.
The report states FTA should oversee additional tests to ensure the support structures will have the 50-year minimum lifespan required for rail structures. Some additional tests were completed this year and confirmed the pier foundations can adequately support an active rail bridge, the report states.
FTA and MWAA are working to comply with the inspector generalís additional recommendations.
The Office of the Inspector General stated, and FTA agreed, that MWAAís contractor should perform additional stray current tests, which are designed to measure the anticipated corrosion rate of metal piles from the electrical current used to power the trains, to prove that the piles will last for 50 years. The report also says FTA should require additional corrosion protection, if the tests find it is warranted.
Pat Nowakowski, the projectís executive director, said the additional stray current tests will be performed, although they have not been scheduled. The additional testing is not expected to affect the overall project budget or schedule, he said.
The testing involves drilling a hole next to some of the existing foundations and inserting test apparatus that measures the electric current in the ground at various depths, Nowakowski said.
In addition to the extensive technical analysis of the pier and pile testing process, the report further criticizes FTAís oversight of the projectís timeline and budget at periods during which there were concerns. The timeline issues have been resolved, and the MWAA Board of Directors has set aside $150 million in additional funding to account for anticipated cost overruns.