The Silver Spring Transit Center was recently found unsafe and in need of major repairs. The $112 million bus and train hub is two years behind schedule and over budget. (Sarah L. Voisin/The Washington Post)

For Montgomery County Executive Isiah Leggett, the Silver Spring Transit Center has been the heaviest patch of turbulence in what has so far been a relatively smooth trip to a third term.

Leggett has taken a hammering from his Democratic primary opponents for the problem-plagued project, thrown more than two years and tens of millions of dollars over budget by design and construction defects.

In response, he has said he accepts full responsibility for the fiasco and hopes to turn the center over to Metro this summer for an opening later this year.

But Leggett’s transit center troubles may have worsened with the report of an independent advisory committee he commissioned. It warned that while a major collapse is unlikely, the public will be at increased risk from isolated instances of falling concrete unless interior beams and girders are strengthened before the facility is opened.

The report of the committee, headed by former Lockheed Martin chairman and chief executive Norman Augustine, countered repeated assertions by Leggett and the county’s engineering consultant, KCE, that any remaining questions about the building involve long-term durability, not safety.

Concrete issues at the Silver Spring Transit Center

Leggett said last week, after the report’s release, that the decision on the beam and girder work would be made by Metro. The transit agency is due to take control of the facility from the county after its completion.

“We’ll do whatever they want,” Leggett said, emphasizing that the transit agency is effectively the county’s client on the project.

His response has drawn intensified criticism from primary opponents Phil Andrews and Doug Duncan, who said Leggett has gone from “the buck stops here” to buck-passing. They contend that the county is obligated to reinforce the beams and girders before conveying the facility to Metro.

“It seems to me at this point there is only one option the county can possibly pursue,” said Council member Phil Andrews (D-Gaithersburg-Rockville) “I don’t see any justification to wait and see what Metro wants to do.”

Duncan, a former three-term county executive (1994-2006), was more pointed.

“It would be morally irresponsible for the county to turn over something that they know has life-safety issues,” Duncan said. “And Metro, above all, should be worried about life-safety issues given their record.”

Leggett said Monday that he was not deferring to Metro, but only wanted to give the agency an opportunity to review Augustine’s report before it reached a final position on the reinforcement issue.

“I’m going to do what I think is right,” he said. “We’re not going to do anything that is not in the public interest. I want to do what I ultimately think is the safe solution.”

Leggett is in a bind because he is confronted with conflicting positions taken by key players in the project.

KCE President Allyn E. Kilsheimer, hired by the county in 2012 to investigate severe cracking that developed in the center’s concrete, concluded that the building would have a shortened lifespan — less than the expected 50 years — and high maintenance costs if beams and girders were not fortified against the torsion (twisting forces) and shear (vertical forces) to be generated by the hundreds of buses rolling into the transit hub each day.

But Parsons Brinckerhoff, the building’s designer and engineer, insists that the additional work is unnecessary. Moreover, the firm cautioned that the invasive nature of the beam and girder reinforcement — which involves insertion of steel supports into the concrete — could end up weakening the structure.

In letters to the county earlier this year, Metro said it shared Parsons Brinckerhoff’s concerns. County officials said Monday they are waiting for a final decision from Metro as to how it wants to proceed.

Leggett could opt to remove Parsons Brinckerhoff and find another firm to do the beam and girder work. That could trigger a protracted legal dispute with Parsons Brinckerhoff and throw the project into an even deeper delay.

One possible scenario under discussion is for Metro to open the center but monitor the building for evidence of cracking from torsion and shearing stress with a rigorous inspection program. If such cracking emerges, the work would then go forward, paid for by Parsons Brinckerhoff.

Metro spokesman Dan Stessel said in an e-mail that the agency “will provide a response to the County in the coming days.”

Montgomery officials have been frustrated by the inability of two world-class engineering firms, KCE and Parsons Brinckerhoff, to concur.

“It’s puzzling how two firms can be so different in their conclusions,” said Tim Firestine, the county’s chief administrative officer. He said Montgomery officials have repeatedly pressed Kil- sheimer on the safety question, only to be told there isn’t one.

“I don’t know how many times we’ve pulled the thread with Kilsheimer, but he says there’s not a safety issue,” Firestine said.

The County Council is scheduled to be briefed Thursday by Metro and county officials.

“We’re not engineering experts,” said Council President Craig Rice (D-Upcounty). “We have to rely on folks to give us the best guidance on how to move forward. At the end of the day, Metro is who we are building this facility for. Metro really needs to guide us in what makes the most sense on how to move forward.”