Aesthetic design elements were an important part of the impressive vertical lift span structure that will link the Massachusetts cities of Quincy and Weymouth. © Rosales + Partners
Work begins on a vertical lift span bridge that will serve as the replacement for an Art Deco bascule bridge that once connected the Massachusetts cities of Quincy and Weymouth.
February 26, 2013—Preliminary construction work began recently on the new Fore River Bridge, an impressive vertical lift span structure that will link the Massachusetts cities of Quincy and Weymouth. It will be the third moveable span bridge at the site, indirectly replacing an admired Art Deco bascule bridge opened in 1936 as the nearby Fore River Shipyard was about to play an integral role in World War II.
The state was planning a full renovation of the 1936 bridge in the late 1990s, when extensive damage from alkali–silica reaction was discovered on the span’s massive concrete piers. The degradation was deemed to be beyond repair. The Massachusetts Department of Transportation (MassDOT) then bolstered plans for an adjacent temporary bridge to allow time for the design and construction of a new bridge. Once the temporary bridge was complete, the bascule bridge was demolished.
The engineering firm STV, in New York City, performed the early design work and bridge type selection, taking the design to the 25 percent level on most elements, and 70 percent on the vertical lift span. Although the shipyard has since closed, nearby oil terminals are anticipating the arrival of post-Panamax ships. They petitioned the U.S. Coast Guard for a 250 ft wide channel, significantly wider than the 1936 bridge’s 175 ft.
“That drove the bridge type,” says Mark Ennis, P.E., M.ASCE, the STV project director. “A fixed bridge was considered, but was quickly eliminated because of the massive impacts to the neighborhoods. A tunnel was considered as a possibility, but the cost and the number of takings required were onerous.”
That left the design team with a movable bridge for the replacement. Because the 1936 bridge was so highly regarded by the public, local leaders and residents initially favored a replacement bascule bridge. That option, however, was greatly complicated by the need to widen the shipping channel.
The new bridge’s 250 ft wide channel will accommodate
post-Panamax ships. © Rosales + Partners
“We were very aware that the communities like the appearance of the original bascule bridge and were very keen to have a similar looking bridge,” Ennis says. “So we struck a compromise with the Coast Guard that the minimum channel that they could possibly accept would be 225 feet.”
That compromise enabled the team to seriously consider a bascule bridge. But even with a proposed channel reduced from 250 ft to 225 ft, the team found that elements of the bascule design, including the piers, were taking on enormous proportions. And a bascule span would have required more extensive interruptions in the busy shipping channel. “The clean, sleek, low-level type bridge that everybody had in mind from the 1936 bridge really wouldn’t have been what they got,” Ennis says.
So the vertical lift span that accommodates a 250 ft channel was selected. The architecture firm Rosales + Partners, in Boston, worked with STV and MassDOT on the design to incorporate aesthetic elements that are not common on vertical lift spans. “We are putting in a lot of maintenance walkways and stairways and access points,” Ennis says. “That should help for the long-term maintenance of the bridge, but tends to clutter up the appearance of the towers. What we came up with, working with the architect, was we would move those features into specific areas and wrap those with a stainless steel mesh material that will be semitransparent.”
The vertical lift span carries an added benefit for MassDOT: the new bridge will have a 60 ft vertical clearance when closed, enough to enable most of the abundant yachts and pleasure boats in the area to pass without the need for an opening. An estimated 32,000 motorists a day use the bridge.
Because traffic has been diverted onto a temporary bridge since 2002, the new bridge will be constructed on the alignment of the 1936 bridge. The bridge’s impact system was designed for a fully loaded Panamax ship traveling at speeds common in the shipping channel.
In August 2012, MassDOT awarded a $244-million contract to White-Skanska JV, a joint venture of Skanska AB, Stockholm, Sweden, and JF White Contracting Company, Inc., in Framingham, Massachusetts, to complete the design and construct the bridge.
The team is working on a test shaft for the multiple drilled shafts that will be required to found the large steel towers. The design calls for massive 8 ft diameter drilled shafts extending through about 110 ft of soil and 20 to 30 ft into bedrock.
The bridge is scheduled for completion in 2016.