In a dispute over whether the Silver Spring Transit Center is structurally sound, Montgomery County and general contractor Foulger Pratt will bring in a third engineer to analyze the situation and hopefully resolve the differences, David Dise, director of the county Department of General Services, said Thursday.

On the one hand, Parsons Brinckerhoff, which designed the structure, has found that more than half of the concrete on the second and third levels is either too thick or too thin. The third level is planned to hold 32 bus bays for Metro, Maryland Transit Administration and Ride On buses. Several areas are cracked or flaking, and the steel support beams are exposed in some areas. As a result the concrete does not meet the American Concrete Institute’s or Metro’s standards.