John Greenleaf Whittier Memorial Bridge

Massachusetts Department of Transportation wanted to expand a 4-mile stretch of I-95 from three lanes to four lanes in each direction, but the John Greenleaf Whittier Memorial Bridge stood in the way. The major, three-lane bridge on the interstate carried 80,000 vehicles a day over the Merrimack River. To widen I-95, the obsolete bridge would have to be replaced with a wider structure, and no one was certain how to do that without closing lanes and causing backup nightmares on I-95. No one, that is, until HNTB teamed with design-build contractor Walsh-McCourt.

As lead designer and engineer-of-record, HNTB designed the John Greenleaf Whittier Memorial Bridge and Interstate 95 improvements as part of MassDOT’s Accelerated Bridge Program. HNTB drew on extensive expertise in designing the innovative, network-tied arch bridge, which is one of only 14 in the U.S.

The accelerated schedule meant submitting multiple early-release packages and gaining consensus from both the contractor and owner. Tackling one of MassDOT’s largest projects ever, HNTB focused on a constructability with a plan to build the John Greenleaf Whittier Memorial Bridge one span at a time and while preserving its architectural and historic elements. With its innovative, unique proposal, HNTB delivered several firsts for the client, including a network tied-arch bridge, EPS wall, shared-use path along a Massachusetts interstate and new Pine Hill Bridge featuring continuous, curved steel girders, variable skews at the ends, an intermediate pier and integral abutments. In addition, the HNTB team managed bridge demolition, designed retaining walls, lighting and aesthetics, coordinated utilities, drafted drainage and stormwater treatment plans, secured environmental permits, led public outreach efforts.

The design-build project expanded a 4-mile stretch of I-95 from three lanes to four in each direction, repaired and widened a major three-lane bridge and replaced or rehabilitated several other structures – all while maintaining six lanes of traffic to avoid major traffic backups. Despite numerous challenges, HNTB met every deadline, and, during the five-year construction period, there were no delays or cost overruns associated with design.