Correction: A previous version of this article mistakenly shortened the name of project designer and structural engineer Parsons Brinckerhoff on second and third reference. The firm should not have been called Parsons, which is the name of an unrelated engineering and construction firm based in Pasadena, Calif., that has no connection to the troubled transit project. This version has been corrected.

The contractor that has overseen construction of the long-delayed Silver Spring Transit Center said Thursday that Montgomery County officials are to blame for the problems that have plagued the project.

In an interview intended to counter mounting criticism, the head of the Foulger-Pratt Companies said that the county had provided incomplete designs and inadequate oversight for the building of the bus-and-rail hub.

The complex, at Colesville Road and Wayne Avenue, has yet to open.

“Montgomery County is the owner of this project,” Bryant Foulger, a principal of the firm, said in one of his first extensive interviews on the transit center. “They have the responsibility to figure out what needs to be done and hire the architect, engineers and consultants to meet the codes.”

In a long-awaited report released March 19, independent engineering experts said they had discovered problems with the transit center that included insufficiently strong concrete and inadequate steel reinforcement.

Concrete issues at the Silver Spring Transit Center

With its costs estimated at $112 million and its opening more than two years behind schedule, the transit center, in the heart of downtown Silver Spring, has become a very public mess. County officials and contractors have been trading blame, and Metro, which is supposed to operate the complex, has said it could reject the structure if it’s not satisfied with the fixes.

The interview with Foulger, held in the firm’s Rockville headquarters and attended by his lawyer and an outside public relations consultant, was the company’s most forceful attempt yet to deflect criticism of its role in the troubled project.

“They put the blame on just about everybody they could find without accepting responsibility that they’re managing the design and construction of this project,” Foulger said.

Asked to respond to the company’s assertions, John Markovs, the county lawyer overseeing the fallout from the project, said Thursday that Foulger’s criticism was “obfuscation.”

“That’s another attempt by Foulger-Pratt to shift blame for defective construction onto the county.”

The cost of fixing the problems and finishing the project are uncertain, and the stakes for the county and the company are significant.

For the county, the delays are an embarrassing distraction as officials try to accelerate economic development, particularly around transit hubs such as Silver Spring. For the company, the negative publicity could threaten its reputation across the region.

The concrete and steel structure is envisioned as a hub for cabs, bikes, MARC trains and Metro’s rail and bus services. Its construction has been a complex undertaking because it has three levels that each must be able to bear the weight of large buses.

The project is millions of dollars over budget, and the report by KCE Structural Engineers assigned blame to several players in the project.

KCE said there were “errors and omissions” by the designer, Parsons Brinckerhoff; the general contractor, Foulger-Pratt; an inspections firm, Robert B. Balter Co.; and other subcontractors.

In the interview Thursday, Foulger disagreed. He said the county mismanaged the project, and that the “design wasn’t fully completed and coordinated” among Parsons Brinckerhoff, the county and his company.

Foulger pointed to several poster-size drawings dotted with dozens of red marks, showing a multitude of changes in the plans.

One of the major safety questions in the project involves steel cables in concrete slabs of the structure.

The KCE report found that the steel cables were not put in two critical 10-foot-wide slabs in part of the project. But Foulger said the contract documents and other plans didn’t require the added steel supports in that area.

“We are responsible to build it to the plans and to the specs,” he said.

Markovs, the county lawyer, said that the plans by Parsons Brinckerhoff called for steel cables on both the second and third floors of the structure but that Foulger Pratt only installed them on the third floor.

“Why would you bother putting it on the top deck and never putting it on the middle deck?” Markovs said.

County officials have said they are worried about the safety of the structure.

They say that if the lack of steel had gone undiscovered, the roadway could have failed, creating a risk that pieces of concrete could fall from the first-floor ceiling onto cars and pedestrians.

Another major issue in the project has been the strength of the concrete.

KCE pulled samples from the site and found a strength of 6,970 pounds per square inch on portions of the project’s second and third floors — below the contractually required 8,000 psi.

“Foulger-Pratt can’t escape liability for giving concrete that’s substandard by hiding behind the reports of an inspector hired by the county,” Markovs said. “The county didn’t get what it bargained for. Why and how that happened is on Foulger-Pratt to explain.”

Foulger defended the way his company handled the concrete.

“All the test results we had, the vast, vast majority of them were telling us we were meeting or exceeding the concrete strength requirements of the contract,” he said.

Foulger said he wants his company to be involved in fixing the project.

“We want to get this open,” he said. “That’s all we’ve ever really wanted to do.”

Pictures of the company’s projects, many of them in Montgomery, line the dark-paneled hallway of Foulger’s reception area.

“We’ve been in business for 50 years,” he said. “We have core values that we follow.” In this project, he said, “We have not been treated well by the county.”