In one of its largest, most complex accelerated bridge construction projects to date, MaineDOT replaces an interstate bridge in a single weekend.

Replacement of the bridge carrying I-295 over Veranda Street in Portland, Maine, is a story of complex challenges converted into opportunities. After six decades of use, the Veranda Street Bridge was due for replacement. Its owner, Maine Department of Transportation, wanted to replace the old bridge with a shorter, low-maintenance structure. The project also included reconfiguring Veranda Street, a two-lane divided roadway beneath the bridge. With confusing interstate on and off-ramp configurations that promoted high-speed travel and an environment unfriendly to pedestrians and bicyclists, Veranda Street was prone to frequent crashes.

Using conventional construction methods would have required a four-year endeavor that included building a large temporary bridge and temporarily closing the I-295 northbound off-ramp. Daily traffic jams would have been the norm for the nearly 55,000 motorists who travel this busy stretch of I-295 each day.

Recognizing these challenges, engineer of record HNTB worked together with MaineDOT to reimagine the project and leverage the strong benefits of accelerated bridge construction (ABC).

“MaineDOT prides itself on being a customer-focused agency,” said HNTB Project Manager Tim Cote. “Its leaders were concerned about the significant impacts that conventional construction would have on traffic flow and mobility. ABC balanced the project constraints and enabled swift delivery of a quality project on one of the most heavily traveled corridors in the state.”

Using ABC, MaineDOT replaced the old, three-span bridge with a new, low maintenance single-span structure in one weekend. Work began to remove the existing structure on Friday, April 22, 2022, at 6:45 p.m. By Monday, April 25, at 6:54 a.m., the new bridge was in place, paved, striped and open to traffic.

“Drivers who had used the old bridge to get home on Friday evening were able to cross a brand-new bridge on their return to work the following Monday,” said MaineDOT Commissioner Bruce Van Note.

Achievement driven by scrupulous planning

MaineDOT previously had completed projects using ABC methodology, but the Veranda Street Bridge was among the largest, most complex and most ambitious ABC projects the agency had undertaken. Although the approach required an I-295 closure, the shutdown was limited to a single weekend. This minimized impacts to the traveling public and eliminated up to four years of daily travel delays on I-295, reducing user costs by 80% and enhancing safety for workers and motorists. Costs were comparable to conventional construction, because the premium associated with ABC was largely offset by elimination of the temporary bridge.

Removing the old Veranda Street Bridge and installing its replacement in the tight weekend window of just 60 hours required meticulous planning, design and coordination. Beginning in March 2021, the contractor consolidated the Veranda Street roadway to remove its wide grass median and temporarily relocate the roadway beneath the southerly span of the existing bridge. This created needed space adjacent to the highway and allowed for the construction of the upper portions of the new bridge on temporary supports away from traffic. New foundations were constructed under the old bridge as traffic passed overhead unimpeded. Once the new bridge foundations were mostly complete, the Veranda Street roadway was shifted into its final location beneath the north span of the existing bridge in summer 2021.

Because the new bridge would be shorter than its predecessor, the remaining area beneath the southerly two spans of the old bridge were converted into lightweight embankments to prevent post-construction settlement. The embankments were built primarily using 8-foot-by-4-foot-by-3-foot expanded polystyrene blocks, with lightweight cellular concrete placed atop the blocks and used to backfill the remaining, hard to-access areas. This combination of lightweight fill allowed the embankments to be built to within inches of the underside of the existing bridge without affecting traffic and before the bridge above was demolished, saving precious time during the closure.

During the April 2022 weekend closure, the bridge deck and steel bridge beams were removed by noon on Saturday. By the early morning hours of Sunday, the two new, 800,000-pound Veranda Street Bridge structures had been successfully lifted, moved and set into place.

Throughout Sunday, crews installed two dozen precast approach slabs, placed and compacted thousands of yards of gravel and, through the early hours of Monday, paved the roadway and installed temporary concrete barriers. I-295 reopened a full four hours early and just in time for the busy Monday morning commute.

Recognizing the expanded reach realized by using virtual public meetings, MaineDOT held its first-ever live “virtual podium” public meeting a few weeks before the closure. Participants listened to the meeting and submitted questions in the chat box, which the project team answered in real time.

Beyond public meetings, an extensive multimedia campaign that utilized print, digital, television and radio advertising was a key component of the community outreach to communicate the upcoming closures. All efforts pointed motorists to the project website to learn specifics about the project, the closure and available detour routes to reduce the impact on travelers.

During the weekend closure, live-streamed video gave the public a virtual front-row seat to ABC in action. Being able to see the activity, construction manpower and equipment on the project site satisfied the community’s curiosity about how a major bridge project could be accomplished in such a short period. The live stream received more than 75,000 views during the weekend closure.

Outreach so successfully involved the community that nearby residents held a block party to watch the old bridge demolition.

“Neighbors were out with their coolers, cheering together as the bridge came down,” Cote said. “The morning the project opened, news articles and social media were marveling at what an accomplishment it had been. I can’t think of another project for which the public feedback has been so universally positive.”

ABC delivers on MaineDOT’s project goals

The Veranda Street Bridge replacement resulted in a new, lower-maintenance bridge with a 100-year life. Construction was completed in record time with broad public support. Veranda Street improvements modernize and simplify the local roadway, eliminating one of the highest crash locations in the state and establishing a 1.4-acre community green space. New bike lanes, sidewalks and a multi-use path emphasize MaineDOT’s commitment to safely and effectively accommodating all users.

“ABC prevented an extended interstate closure that would have caused significant disruption to the people who live and work in Portland,” Van Note said. “MaineDOT formulated a plan, communicated that plan to our customers and then did what we said we were going to do. The Veranda Street Bridge Replacement project embodies MaineDOT’s core values of integrity, competency and service.”