The busiest stretch of highway in Maine is going to be shut down to traffic for almost three days next month, a move that will allow construction crews the time they need to install a new bridge over Veranda Street in Portland.

A section of Interstate 295 between Portland and Falmouth will close for 64 hours in late April. During that time, crews will remove the 61-year-old Veranda Street bridge and replace it with a completely new bridge. The new bridge, which is under construction next to the old bridge, will be rolled into place.

This photo of the Veranda Street bridge shows the white geofoam blocks that will be used to support the foundation of the new structure. To the left of I-295 is the deck of the new bridge, which will be rolled into place once the old bridge is demolished and removed. Photo courtesy of Maine Department of Transportation

Officials from the Maine Department of Transportation said they chose to use the roll-in technique to limit the closure on I-295 to 64 hours as opposed to the years it might have taken to complete if normal construction methods were used.

Despite the state’s accelerated bridge replacement plan, thousands of motor vehicles will still be impacted by the closure, which is scheduled to start at 7 p.m. Friday, April 22, and end at 11 a.m. Monday, April 25. In conjunction with the I-295 closure, Veranda Street will be closed from April 18 through April 25.

MaineDOT said it is doing everything it can think of to spread the news about the closure, including hosting a live virtual meeting at 6 p.m. on April 6 during which the public can hear a presentation and ask questions about the $20.8 million project. Project fliers have been mailed out to businesses and residences in the Portland-Falmouth area.

“This project has the potential to impact people from Aroostook County to Rhode Island,” MaineDOT spokesman Paul Merrill said Wednesday evening in a telephone interview. “We hope that no one is surprised or shocked by what we are planning to do.”

Merrill said that before the pandemic the stretch of I-295 near Tukey’s Bridge in Portland and Route 1 in Falmouth averaged 53,000 vehicles a day.

“It’s the busiest stretch of road in Maine,” he said.

The state said the Veranda Street Bridge is nearing the end of its useful life and needs to be replaced for safety reasons.  The bridge was built in 1961 and MaineDOT rates the deck condition as poor and the bridge overall as structurally deficient.

State officials said they realize there is no perfect time to undertake a project of this magnitude but chose the weekend in April when they expect traffic to be lighter than it would be after the Memorial Day weekend in May.

Originally, MaineDOT had planned to shut down I-295 in October, but had to delay the closure until April due to a national resin shortage that slowed the process of obtaining replacement geofoam blocks for the bridge. The delay occurred after crews found that some of the blocks that were to be used to support the bridge foundation had been damaged. The resin shortage made it impossible for the state to find replacement blocks in October.

The new bridge was constructed using what the state refers to as an accelerated bridge construction design process. Accelerated bridge construction is not uncommon, but is used more extensively in other parts of the country.

A Self-Propelled Modular Transporter – or SPMT – will be used to move the new bridge structure into place during the 64-hour interstate closure, according to Merrill. SPMTs are used to transport massive objects that can’t be moved by trucks. Most notably, NASA uses SPMTs to move space shuttle components. This is the first time MaineDOT will be using an SPMT.

According to the Federal Highway Administration, accelerated bridge or slide-in bridge construction is a relatively new process that allows states to reduce the amount of on-site construction time needed to build or replace bridges. The FHA says the technique can significantly reduce traffic impacts, especially in urban centers with high traffic volume, by reducing planning and construction efforts by years.

For more information about the project or to register for the virtual presentation on April 6, go the Veranda Plan website: verandaplan.org