Temporary Bridge Takes Shape, Traffic to Switch by Mid-July

Crews are working below the North Washington Street Bridge this week to secure the piers from marine traffic, and following that work they will open the newly-constructed temporary bridge – which will accommodate all modes of traffic for the next two years or more.

The temporary bridge was an accommodation that came late in the project, but was widely applauded as a way to speed up the bridge replacement and ease the pain of congestion on Charlestown. Now, that temporary bridge looks nearly complete to the naked eye, and MassDOT officials said they hope to move traffic there by early July at the latest, but after an online virtual meeting with the Town.

The temporary bridge will be ready to go in late-June to mid-July as traffic moves over from the old North Washington Street Bridge. The diversion will last two years.

District 6 Highway Director John McInerney said crews began working on the piers below to protect them from marine traffic – a time-consuming but necessary safety measure. That will take about four to six weeks, he said, and then they will begin switching traffic over.

“The top side of the temporary bridge is complete,” he said. “It’s all paved and striped. Right now, what’s keeping that up is we just started piles for the pier protection – protecting the steel columns in the water from marine traffic. That’s been challenging to get through…but we’re in the home stretch…In short, you can’t put traffic on the bridge until you know the piers below are protected from being impacted by marine traffic. It will provide protection like a bumper. That will probably take four to six weeks to complete. Once that is done, we’ll open the temporary bridge in late June or early to mid-July. As much as we can push anything, we will.”

Before that happens, as promised, MassDOT will hold a public meeting with the community to let them know what is coming and how the shift will take place. That would have likely been a jam-packed affair at the Knights of Columbus, but such meetings are not possible in the times of COVID-19. Instead, McInerney said they would be holding a virtual meeting prior to the move, which will be announced at a later date.

“We’ve done it in other parts of the state already,” he said. “It’s worked pretty well and in some cases you have people attend that would not normally attend an in-person meeting.

The temporary bridge will be slimmed down for vehicle traffic. While the old bridge has accommodated two lanes in and out for some time – with rolling closures for construction – the temporary bridge will have three total lanes, but two lanes inbound and one lane outbound.

“That will be a little bit of a challenge, but it puts us back where we started when we began the project,” he said. “We estimate we’ll use the temporary bridge for 24 months until we bring the new bridge into service. The real purpose of the temporary bridge is to allow the contractor full access to the existing bridge, which is more efficient and so he isn’t working in stages.”

In that 24 months, everything must go. All that exists of the current North Washington Street Bridge will be demolished – including the decking, the steel, the substructure and the piers. Using barges to carry away the materials, they expect to be done with the demo in four months – so before Thanksgiving and the close of the summer work season.

Once the demolition is done, then the real work of building the new bridge will take place – all while traffic of all kinds whizzes by on a separated bridge next door. The new bridge is designed by the same architect, Miguel Rosales, that did the Bunker Hill/Zakim Bridge, and the new bridge mimics that in a major way – a perfect complement to what exists at the entrance to the Charles River.

After about two years, McInerney said they will move the traffic onto the new bridge, but it won’t be absolutely completed. There will still be some work to do after traffic moves on – including taking down the temporary bridge and the utility bridge.

To date, most of the work since the project started in 2018 has been moving critical utility lines – including a massive electrical line to downtown Boston – onto a temporary utility bridge. That has been time-consuming and arduous, but is now complete.

The North Washington Street Bridge project is one of the only projects in the City of Boston that was allowed to continue through COVID-19 restrictions – as it was deemed essential infrastructure. There were some slowdowns, McInerney said, mostly because of hiccups in the supply chain for materials. However, he said they were able to take advantage a little of the lack of traffic. Even so, most of the work on the project is in the water, so traffic doesn’t impact it as much as a highway bridge.

“We definitely have felt impacts, but not anything as bad as if we shut down the job completely,” he said. “The contractor is pushing things to try to recover time. It may take us some time to understand the full impacts of COVID-19 with this job…We are working extra shifts to make up time. You’ll probably need some time for traffic to go on the temporary bridge before we know if we’ll land where we need to land time-wise.”

The bottom line for MassDOT is the temporary bridge has been a success so far in its construction, and it remains a good idea and a positive add-on to the project – given it wasn’t part of the original bid for construction.

“The project team and the contractor are together and making it work,” he said. “Moving traffic off to the side, it’s a great idea. We’re still holding our breath, but we’re anxious to get the bridge pier protection done and move traffic over. It’s actually a good time to switch things with the reduced volumes of traffic right now.”

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