New temporary elevated highway may be needed with I-90 Allston project

Commissioner says it’s ‘one of the things we’re trying to eliminate’

THE I-90 ALLSTON interchange has always been a challenge to design, particularly squeezing the Massachusetts Turnpike, Soldiers Field Road, and four railroad tracks at ground level into in the narrow area called the throat between Boston University and the Charles River.

But as the state seeks federal funding for the nearly $2 billion project, the staging plan for construction is starting to come together – and may be an even bigger challenge.

Jonathan Gulliver, the state’s highway administrator, says the elevated section of the Turnpike that runs through the throat area was built in such a way that it can’t just be torn down and rebuilt at ground level. Since the idea is to keep traffic flowing while the new highway is built at ground level, the rebuild has to be done in what amounts to a series of chess moves.

First off, the elevated section of the existing Turnpike needs to be shored up so it will last through the seven years of construction.  The state currently spends $1 million a year to keep the crumbling elevated highway upright, but now a “major rehabilitation” is planned. The price tag for the rehabilitation had been $75 million, but the cost rose to $90 million in the state’s application for federal funding.

The biggest surprise in the funding application is that the state is also planning to build a new, temporary elevated roadway capable of carrying half the Turnpike traffic while the old, rehabilitated elevated Turnpike is torn down in stages. 

You read that right. The state does a major rehabilitation of the existing elevated Turnpike and then builds a new elevated roadway to carry traffic while the old rehabbed Turnpike is torn down in stages and rebuilt at ground level. The new temporary roadway would be a lot like a temporary bridge, used for awhile and then discarded.

“This is a one of the things we’re trying to eliminate,” Gulliver said. “The last thing you want to do is add more infrastructure, even on a temporary basis. It’s costly and it’s time consuming.” 

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Bruce Mohl

Editor, CommonWealth

About Bruce Mohl

Bruce Mohl is the editor of CommonWealth magazine. Bruce came to CommonWealth from the Boston Globe, where he spent nearly 30 years in a wide variety of positions covering business and politics. He covered the Massachusetts State House and served as the Globe’s State House bureau chief in the late 1980s. He also reported for the Globe’s Spotlight Team, winning a Loeb award in 1992 for coverage of conflicts of interest in the state’s pension system. He served as the Globe’s political editor in 1994 and went on to cover consumer issues for the newspaper. At CommonWealth, Bruce helped launch the magazine’s website and has written about a wide range of issues with a special focus on politics, tax policy, energy, and gambling. Bruce is a graduate of Ohio Wesleyan University and the Fletcher School of Law and Diplomacy at Tufts University. He lives in Dorchester.

About Bruce Mohl

Bruce Mohl is the editor of CommonWealth magazine. Bruce came to CommonWealth from the Boston Globe, where he spent nearly 30 years in a wide variety of positions covering business and politics. He covered the Massachusetts State House and served as the Globe’s State House bureau chief in the late 1980s. He also reported for the Globe’s Spotlight Team, winning a Loeb award in 1992 for coverage of conflicts of interest in the state’s pension system. He served as the Globe’s political editor in 1994 and went on to cover consumer issues for the newspaper. At CommonWealth, Bruce helped launch the magazine’s website and has written about a wide range of issues with a special focus on politics, tax policy, energy, and gambling. Bruce is a graduate of Ohio Wesleyan University and the Fletcher School of Law and Diplomacy at Tufts University. He lives in Dorchester.

Gulliver said the construction approach is necessary to keep traffic moving during construction and make enough room in the throat to build out the project. But he’s hopeful the engineers can find a way to dispense with the temporary elevated highway, which is referred to as a viaduct.

“There are a lot of needs that force us to look at the project this way. This particular phase, with the temporary viaduct, our hope and our goal is to eliminate the need for it all together,” he said. “My gut tells me there is a way to do that.”