Sumner Tunnel closure: About a third of this summer’s work completed, with 5 weeks to go

Three weeks into the eight-week long closure of the Sumner Tunnel, workers remain busy installing massive arches that will strengthen the structure’s worn out ceiling and enhance its ventilation.

State transportation officials estimate a third of this summer’s work is done, with just over five weeks until the expected completion date of Aug. 31.

Project officials from the Massachusetts Department of Transportation led a group of reporters through the tunnel on Tuesday, showing what has been done since the around-the-clock closure went into effect July 5, and what more needs to be done.

“There is some extra work that the contractor’s dealing with, but I wouldn’t call it unforeseen,” MassDOT District 6 Highway Director John McInerney told reporters as the skies opened up near the tunnel’s entrance. “The work is pretty straightforward … it’s just the amount.”

Workers started installing the precast concrete arches in the middle of the roughly mile-long tunnel, one of the four routes into the city, carrying traffic under Boston Harbor from Logan International and Route 1A in East Boston.

Crews are now spreading the arches outward to both sides of the tunnel, with the concentration on the East Boston section, which must be complete before traffic can travel through again, McInerney said. Some workers were seen Tuesday filling spaces between new arches with orange sealant and grout.

About 16 arches are installed a day, officials said.

“The benefit is you have better lines of sight within the tunnel,” Project Manager Chris Blanchard said of the arches. “We thought it was a better design than what they had in the original concept. Structurally, it made more sense, and it’s quicker to install, get everything done.”

Work also includes removing nearly 4,000 linear feet of ceiling panels and upgrading the lighting, communications and life safety systems of the tunnel.

Highway Administrator Jonathan Gulliver at a press conference in advance of the closure called the project “by far the most impactful … we have undertaken at some time.”

Once the calendar switches to September, the project will shift back to its pre-summer weekend closures. The tunnel will then shut down again 24/7 next July for as long as it is this summer.

The closure has diverted an estimated 39,000 drivers that travel through the tunnel daily, causing multi-mile backlogs along alternate routes and officials to urge the public to “ditch the drive.” The Tuesday morning drive from Eastie to Government Center took nearly 30 minutes, according to Mass511.

“It has had maintenance over the years,” McInerney said of the Sumner, “but it’s getting tired. This gives us an opportunity to bring it up to code.”