Charles Stark, executive director of the Silver Line rail project, told members of the Metropolitan Washington Airport Authority’s Board of Directors, that cracks can appear in these types of precast concrete structures but officials are concerned because the size of these cracks has grown since they were first spotted in April. So far eight of the 662 girders have been placed and the cracks have appeared in the top flange of the concrete structures.
Stark said there are no cracks in the web — or vertical part of the beam — and that cracks in the flange are less of a concern because they are not part of the main body structure. However, any cracks can affect the life span of a beam, he added.
Stark said they have suspended work on that portion of the project. Production of the girders has also been halted. Stark said the lead contractor, Capital Rail Constructors, has hired an independent firm to determine the cause of the cracking. An official with the company said they hope to have more answers by the end of this month. The contractor will pay the cost of recasting the girders and related fixes.
“What will happen depends on what investigation turns up,” Stark said.
Stark said project officials also have hired their own independent consultant to investigate the cause of the cracking and possible solutions.
“This is typically an area of the beam that sees little stress during operation when it’s carrying a train,” he said. “But any crack is something of concern.”
Stark characterized the problem as “a hiccup” and said he doesn’t expect the girder issue to cause further delays unless it extends beyond Labor Day. The second phase of the now $5.76-billion rail project already is 13-months behind schedule.
The first phase of the 23.1 mile Silver Line opened last July with five stops– four in Tysons Corner and one in Reston at Wiehle Avenue. The project’s second phase will have six stops including one at the airport and will, for the first time extend Metro service into Loudoun County.
MWAA is overseeing construction of the Silver Line, which ultimately be operated by Metro.