The new Veterans Memorial Bridge features three observation platforms along the 12 ft wide path. The platforms have tall reed poles to evoke the grasses in the saltwater marshes below. Image by Noel Shamble, courtesy of T.Y. Lin International
By proposing a new alignment to the Veterans Memorial Bridge in Portland, Maine, the design team was able to earn the top technical score at the lowest bid price.
July 31, 2012—One of the busiest river crossings in the state of Maine was dramatically upgraded late last month when state officials opened the new Veterans Memorial Bridge, a gracefully arched 1,610 ft structure linking the cities of South Portland and Portland over the Fore River.
The new bridge is located immediately upstream of—and at a 30 degree angle to—the original Veterans Memorial Bridge, a steel girder structure that was completed in 1954. That structure was rapidly reaching the end of its lifespan as the harsh Maine winters and the corrosive atmosphere of the tidal zone exacted a heavy toll.
The new 4-lane span comprises 361 precast concrete sections ranging from 8 ft to 11 ft wide and 40 ft to 46 ft long, supported by 6 river piers, founded on pipe piles driven as deep as 110 ft through the soft silt and clay river bottom to bedrock. The $63.4-million bridge was a design/build project, awarded to Reed & Reed, Inc., of Woolwich, Maine. T.Y. Lin International, with an office in Falmouth, Maine, was the team’s lead design engineering firm.
The new alignment allowed the new bridge to be built while the
existing bridge was in full use, saving the expense of phased
construction and demolition. Courtesy of T.Y. Lin International
The main design challenge of the project was the alignment, according to Jeffrey Andrews, P.E., M.ASCE, T.Y. Lin’s New England District Director. The state’s 30 percent design called for the new bridge to be parallel to the existing bridge, and close enough to require a complex, phased construction and demolition schedule, impacting traffic on the existing bridge. Further complicating this was a busy rail line below the site, with traffic from Amtrak and Pan Am Freight and multiple utilities on the existing bridge that had to be maintained during construction.
This alignment also called for a much longer bridge that deposited motorists at a busy four-way intersection in Portland with several awkward angles. About 22,000 motorists use the bridge each day. “The city wasn’t thrilled with the existing intersection, and in 20 years, it would be worse,” Andrews says.
The design team devised an alternative that skewed the new bridge upstream at about a 30 degree angle, toward Mercy Hospital. This provided an extensive list of benefits. The new bridge could now be about 800 ft shorter, saving a great deal of money. The new alignment eliminated the need for phased construction as well. Finally, the new bridge would replace the troublesome four-way intersection with two three-way intersections designed for better operational and safety performance.
“It is a much better scenario,” Andrews says. “A shorter bridge means there is less bridge to maintain. Our alignment doesn’t affect traffic on the existing bridge or the rail lines during construction of the new bridge. That made the construction process easier. They constructed the new bridge with the old bridge in place and traffic on it. Our design impacted Mercy Hospital’s property more, but they approved because it gave them increased visibility.”
A memorial to veterans graces the Portland, Maine, side of the
bridge. Courtesy of T.Y. Lin International
By eliminating phased construction and shortening the bridge, the solution enabled the team to submit a bid that was $6 million below the nearest competitor while achieving by far the highest technical score in the process for a “combined $9 million better value to the taxpayers,” Andrews says.
The Maine Department of Transportation placed a priority on the bridge’s aesthetics because of its high-profile location, instituting a significant public involvement program. “There is quite a view if you look downriver,” Andrews says. “We felt that going with a concrete segmental would give us longer spans, fewer piers, and an arch effect.”
To continue the arch theme above the deck, the team devised three observation overlooks along the 12 ft multipurpose path on the bridge. These 8 ft overlooks feature large, bowed poles that the team calls “reed poles” because they were designed to evoke the reed grasses below in the saltwater marsh environment.
“They vary in height. The ones in the center are taller and not as curved. As you go outward, the poles get shorter, but the bend is more pronounced,” Andrews says. “As the reeds blow in the wind, they bend. We felt we needed to have something above deck level that gave them a sense of place and gave them something that would make this stand out.”
There is another observation platform at the South Portland side of the bridge. On the Portland end, there is a larger plaza that contains plaques honoring veterans. These aesthetic elements were refined through the public involvement program, which was a challenge in a design/build environment in which the scope, schedule, and budget of the project are already set. The public was able to select some surface treatments, railings, and landscape features.
Andrews says it was enriching to work on a project so close to the office that he and the staff could watch the progress daily.
“It was gratifying to be able to be that close to see the bridge being constructed,” he says. “By all accounts it went off very, very well. So we are pleased that Reed and Reed selected us on their team and together with MaineDOT [Department of Transportation] we came up with a great solution and it worked for everyone.”