It’s a two-year construction project that will take place on and under City Hall Plaza, shuttering an integral junction in the city’s transit system and creating delays for tens of thousands of commuters who travel daily through the heart of the city.
And, without a hint of irony, T officials promise: It will be worth it.
Government Center T station will close Saturday until spring 2016 for an $82 million overhaul.
The project will be capped by innovative landscaping and a gleaming, four-story glass headhouse designed to reshape the look and feel of dreary, windswept City Hall Plaza. But most of the construction — and the reason the project is scheduled to take more than two years to complete — will occur underground and behind the scenes.
“The below-grade elements are the bulk of the work,” said Dan Beaulieu, the Massachusetts Bay Transportation Authority project manager. “The headhouse is almost the bride and groom on the wedding cake.”
The prime purpose of the project is simple: elevators. Government Center, the ninth-busiest station in the system, is the T’s biggest transit hub with no way for people who use wheelchairs to enter or exit. So two sets of elevators will be installed inside the station.
Parts of the station date to 1898, and it has not seen a major renovation since the 1960s. MBTA general manager Beverly A. Scott said the station is ripe for rejuvenation.
“The scale of this is really a complete redo and modernization. There are actually parts of Government Center that are more than a hundred years old,” Scott said. “It’s time. This is the big one.”
Why, though, would the installation of two sets of new elevators necessitate a two-year project? For example, last year, when the T closed Orient Heights Station in East Boston for a handicapped-accessibility overhaul, the project took eight months.
But officials say that the labyrinthine layout of the antiquated Government Center Station means that the seemingly straightforward task of making the station accessible requires that practically every feature be changed in this station where the Blue and Green lines converge.
For example, when architects sought to find a place to install an elevator between the Blue Line station and the Green Line platform that sits one story above it, there was only one spot that aligned with both platforms — and that spot is where the stairs are now. Construction crews will have to demolish the stairs and rebuild them elsewhere before installing the elevators.
And in order to power the multiple sets of elevators, electricians must build a new, higher-capacity electrical substation.
Also, adjacent to the Green Line tracks, the floor of the platform must be raised 8 inches to accommodate wheelchairs. That means that everything that touches the platform floor — stairs, escalators, walls — must be modified or replaced.
In addition, there will also be upgrades to the lighting, communications, and safety systems for the trains.
‘The scale of this is really a complete redo and modernization.’Beverly A. Scott, MBTA general manager
“All the mechanical, electrical, and subsystems work — that is going to be unseen work, but it’s critical infrastructure,” Scott said. “We’re talking about major stuff.”
Previously, T officials had considered an alternative construction plan that would have kept the station partially open during construction, but would have spread the work over four years. They opted for the two-year schedule instead, which is estimated to cost about $20 million less and will be safer for work crews, Scott said, especially those that must install the new headhouse directly over tracks that continue to serve trains running through the station.
Closing the station completely will mean major headaches for commuters, especially those seeking to transfer between the Green and Blue Lines. Instead, riders must detour on the Orange Line through Haymarket or Downtown Crossing stations, then pick up the Blue Line at State Street.
There will also be buses shuttling customers between Haymarket, Bowdoin, Government Center, and State Street stations, but people who choose to use the shuttle — or, to walk — must pay a second time if they intend to reenter a T station and don’t have a monthly pass.
It will be a while before the more exciting improvements appear above ground.
The headhouse — a completely new entrance to the station — will be glass and steel, jutting 40 feet into the air and allowing natural light to permeate the station down below.
“Central to the station’s design has been the concept of a light, contemporary, and visually transparent glass element that would serve as a welcoming beacon,” Beaulieu wrote in a summary of the architectural plans.
The entrance will feature sliding doors and additional fare gates. Outside, the plaza will receive new landscaping, and a lot of it — though much of that work will continue until the end of 2016, after the station reopens to customers.
Listing City Hall Plaza in its “Hall of Shame,” the nonprofit design advocacy group Project for Public Spaces calls it “one of the most disappointing places in America — not just because it failed so utterly, but because it has been a failure for so long. . . . This reviled place has been [Boston’s] centerpiece for over 30 years.”
Robert Uhlig, president of the Halvorson Design Partnership, the landscape architecture firm that created the new layout, said designers hope to erase the feeling of walking through a barren wasteland.
“When you’re out there, there’s no canopy and there’s no ceiling,” Uhlig said. “It’s so vast, horizontally and vertically. . . . We hope to bring the scale of that area down and give the feeling you’re in a room within that overall open space.”
The seemingly endless sets of stairs that commuters climb as they approach the T station will largely disappear, replaced by granite ramps and shallower terrace steps with built-in benches.
Finally there will be trees, dozens of them, in neat rows around the station, irrigated in part by runoff from the station headhouse and permeable bricks that will collect ground water. The trees, Uhlig said, should lower the temperature of the plaza in the summer and alleviate the feeling of a frozen tundra in the winter.
Landscape designers sought to ensure that their design would not get in the way of large-scale events that take place annually on the plaza, such as Boston Calling, Boston Pride, and “big top” tent theater and circus shows.
Uhlig said he hopes the finished plaza will prompt some appreciation for the space, as well as the much-maligned City Hall building.
“I think one of the beauties of this project is that it will utilize and respect those geometries, while still softening the edges,” he said. “It will be interesting to see, socially, how that plaza will change,” Uhlig continued. “Hopefully it will become more readily useful.”Martine Powers can be reached at email@example.com. Follow her on Twitter @martinepowers.