The Silver Spring Transit Center does not meet Montgomery County building code requirements, although it may meet minimum national safety standards, a new engineering analysis has found.
The analysis by Parsons Brinckerhoff, the structural engineer Montgomery County commissioned to design the $112 million project, disagrees with a March report by general contractor Foulger-Pratt Contracting that said the facility is more than strong enough to serve its intended purpose.
The structure is planned to hold 32 bus bays for Metro, Montgomery County Ride On and commuter buses, as well as 54 kiss-and-ride and taxi spaces and connection to MARC and Metrorail trains.
Parsons Brinckerhoff designed the structure to be safer, more durable, stronger and longer lasting than the schematics Foulger-Pratt's engineer used for its analysis, wrote Parsons Brinckerhoff Supervising Structural Engineer Douglas Lang. Since the county paid for those higher standards, that should be the expectation.
Lang went on to say that the American Concrete Institute standards Foulger-Pratt has used provide the "minimum requirements necessary," but that the county requires higher standards.
"The facility does not meet the Montgomery County code requirements," Lang said, and the method Foulger-Pratt-commissioned engineer Simpson Gumpertz & Heger used to test the strength of the Silver Spring Transit Center did not test for the heaviest possible loads the structure could face.
But Foulger-Pratt stood by its engineer's analysis. Since the structure is 95 percent complete, the engineers were able to test the existing structure, rather than having to rely on design schematics, said firm Principal Clayton Foulger.
"That structure meets the load tests that are required of it in a safe way," he said. "Now, is it exactly the way it was designed? No, it is not."
A previous analysis by Parsons Brinckerhoff discovered roughly 63 percent of the concrete on the facility's second and third levels are either too thin or too thick, and in several places the steel supports are inadequately protected from weather erosion.
That report has left the county and Foulger-Pratt disputing whether the facility is strong enough to withstand the weights it needs to and what needs to be done to fix the problem. The county has weighed suing the contractor, and Metro has still not said whether it will accept the facility for use.
The county has enlisted a third engineer to analyze both Foulger-Pratt's and Parsons Brinckerhoff's data in the hopes that the county and its contractor can reach an agreement, said Department of General Services Director David Dise.
Foulger said he does not expect the dispute to result in any new delays. The facility should open to the public in August or September, he said.