Mystic ― The Mystic River drawbridge is slated to undergo a yearlong repair project, starting in the spring of 2026, to extend the life of the more than 100-year-old bridge.

The state Department of Transportation and design consultants outlined the estimated $3.7 million construction project for the iconic bridge over the Mystic River during a virtual information session Monday evening.

The purpose of the project is to keep the bridge in a good state of repair and address its load-carrying capacity and structural, mechanical, electrical, architectural, fender system and waterway deficiencies, said John Miller, project manager with Close, Jensen and Miller PC, which is the project designer along with Hardesty and Hanover LLC.

The 220-foot-long bridge, with three fixed spans and one bascule lift span for marine traffic, was built in 1922 and rehabilitated in 2013. The bridge opens an average of 2,200 times a year and is one of the state’s top tourism attractions, said Miller.

The project includes strengthening and repairing steel parts that are aging and deteriorating; reconditioning machinery; making electrical upgrades; re-pointing stone masonry; painting and improving the security of the control house; and adding a closed-circuit television and public address system, according to the presentation.

The DOT also is proposing to install steel bikeway plates to address concerns from local bicyclists about riding over the open steel grid deck, he said. The DOT currently has warning signs on both sides of the bridge to advise bicyclists of the steel grid deck, and some bicyclists choose to ride in narrow concrete-filled strips on the bridge deck.

Miller said the DOT had conversations with the city of Milwaukee, which has installed perforated steel bikeway plates on bridges, and is proposing to install the plates for the first time in Connecticut on the Mystic bridge. The undertaking will require coordination with the DOT’s maintenance staff and others to design a product that will ensure the safe travel of bicycles and other vehicles, while minimizing maintenance costs.

The DOT plans to monitor and evaluate the plates once installed.

“If major safety concerns are discovered, the department will re-evaluate their use at that time,” Miller added.

Miller said most of the bridge project construction won’t interrupt traffic, but there will be some single-lane closures with alternating one-way traffic, including during the installation of the bike improvements. The DOT does not anticipate a full road closure, but given the age and condition of the bridge, the agency has identified a 5.3-mile detour that could be used as needed.

Most of the work also won’t affect marine traffic, he said. Short-term interruptions will be coordinated with the U.S. Coast Guard and local officials, and the intention is to schedule work that would affect marine traffic during the winter months.

The project will require a significant permitting process, he said.

The project will be funded 80% with federal funds and 20% with state funds, said DOT Project Manager Meziane Meziani.

After the presentation, people asked questions, including about the impacts on neighboring properties, where staging will take place, and impacts on parking, and also expressed that they hoped the bike improvements would be permanent.

Miller confirmed that construction will not impact landowners or businesses on either side of the bridge.

He said he believes alternating one-way traffic will be adequate for the majority of work and the staging can be within that lane closure and not disrupt adjacent parcels and businesses in the heavily traveled corridor.

He said the project should not impact parking, and there will be language in the contract that the workers are not expected to use up all the available parking.

The DOT said in a news release that people can send comments and questions by Aug. 12 to DOTProject0058-0343@ct.gov or they can call 860-594-2020.

k.drelich@theday.com