NO. 6: Chelsea: U.S. 1 NB/SB Viaduct Rehabilitation

NO. 6: Chelsea: U.S. 1 NB/SB Viaduct Rehabilitation

This project was challenging.

Faced with an aging inventory of structures, the Massachusetts Department of Transportation Highway Division partnered with HNTB to tackle a long stretch of elevated viaduct running through the heart of Chelsea, north of Boston. The viaduct had fallen into disrepair and had caused congestion and vehicle incidents because of the structural deficiencies.

The $170 million project was designed in 18 months, and now, with a substantial amount completed after 30 months of construction, MassDOT’s Chelsea Viaduct replacement project serves to showcase accelerated design and construction techniques, as well as how the team’s collaborative environment led to the successful removal of nearly 300,000 sq ft of bridge deck area from the state’s deficient list.

It consisted of two separate viaduct sections carrying U.S. Route 1 northbound and southbound from County Road Overpass to the Tobin Bridge, passing over several local roads and the Massachusetts Bay Transportation Authority (MBTA) commuter rail. The team chose to take an accelerated rehabilitation and replacement design approach, but that was difficult because of the age and detailing from circa-1950s construction, coupled with a complex superelevated geometry over horizontally curved roadway sections.

Moreover, U.S. Route 1 is a major artery to downtown Boston. MassDOT mandated that impacts to traffic and roadway closures be minimized or avoided to the maximum extent practicable, and for designs to incorporate accelerated techniques to reduce overall construction duration on the heavily traveled corridor.

MassDOT had also advanced an adjacent major project to repair and rehabilitate the Tobin Bridge carrying traffic at the southern end of the project. Each project was tasked with additional design and construction coordination to ensure a consistent, accelerated schedule, as well as a uniform sequencing for efficient traffic management through the overlapping work zones.

Project: Chelsea: U.S. 1 NB/SB Viaduct Rehabilitation

Location: Chelsea, Massachusetts

Owners: Massachusetts Department of Transportation – Highway Division

Designer: HNTB Corp.

Contractor: Skanska-McCourt, Joint Venture

Cost: $169,371,930 (Low Bid)

Length: 4,011 ft (0.76 miles)

Completion Date: Nov. 1, 2021

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