During construction, the new Silver Spring transit center was found unsafe and in need of major repairs. (Sarah L. Voisin/The Washington Post)

Montgomery County “failed at every turn” to properly manage construction of the Silver Spring Transit Center, an attorney for the project’s general contractor said Thursday.

The county and Metro late last month sued Foulger-Pratt, saying that the Rockville-based construction and real estate firm’s failures contributed to five years of delays and $50 million in cost overruns for the troubled bus and taxi hub, which is scheduled to open Sept. 20.

The project’s designer, Parsons Brinckerhoff, and inspection firm Robert B. Balter Co. were also named as defendants in the suit, filed in Montgomery County Circuit Court. The suit seeks more than $160 million in damages.

The lawsuit accuses Foulger-Pratt of being negligent by failing to strictly supervise work on the three-level concrete structure next to the Silver Spring Metro station. The building was plagued by cracks and other construction and design deficiencies, the county alleges.

In a statement, Foulger-Pratt attorney Judah Lifschitz said the company was disappointed with the county’s decision to sue and expressed confidence that its position would prevail in court.

“From early on in the project, Foulger-Pratt made it clear to the county that problems with the Silver Spring Transit Center are of the county’s own making,” Lifschitz said. “The project was plagued from the outset by incomplete, uncoordinated and defective design and gross mismanagement. The county failed at every turn to properly manage the project and, in particular, mitigate the impact of its design defects.”

Lifschitz said the company and its subcontractors “are owed millions of dollars resulting from systemic design defects and the county’s gross mismanagement of the project.”

Representatives for Balter, which oversaw pouring of the center’s concrete and other key activities, did not return a phone message seeking comment.