Mystic - Pedestrian and vehicular traffic flowed mostly unabated over the Mystic River Bridge this week as contractors scrambled to put the finishing touches on a three-year bridge rehabilitation project.

Alternating one-way traffic is a thing of the past, and by week's end, state Department of Transportation bridge project manager Brent Church said, designers are expected to visit the bridge for a test of the computer, mechanical and electrical systems. That will be followed later by an overall DOT inspection.

The end is near, Church said.

"If everything is functional and meets the job specs and designers are happy, everybody signs off and that's it," Church said.

He added that "99.99 percent of the work is done. We'll keep our fingers crossed there are no bugs."

Overall, the work is slated for completion by May 16, according to the $14.8 million contract with Cianbro, Church said. Substantial work and opening of marine traffic was to be done by April 15. Church said punch list items, such as touch-up painting, is likely to continue over the next few months.

On Wednesday, there was still a flurry of activity on the bridge with a barge-anchored crane hoisting concrete blocks and steel plates for placement inside the bridge's counterweights. Elsewhere, electricians climbed inside a manhole to access the vehicular barrier gate.

Church said the entire operating system of the bridge is new, but the historic integrity of the bridge, built in 1922, remains intact. Structurally, with the new repairs, the bridge should last at least another 50 years, he said.

The biggest addition to the bridge is a barrier on the Stonington side of the bridge that is meant to prevent vehicles from driving off the side of the bridge when it is raised to allow boats through.

Mystic Chamber of Commerce President Tricia Walsh said the end of the bridge project is a turning point for local businesses who, while happy with the accommodations made by contractors, are exhausted from the construction work in the area.

The bridge project overlapped with Groton's delayed streetscape beautification project involving street, sidewalk and utility work, all in the historic downtown area.

Frustrations have simmered, Walsh said, with annoying shutdowns and construction occurring in front of shops.

"It's tough on businesses and through word of mouth, bad news spreads," Walsh said. "People were afraid to go downtown for fear of the traffic and construction."

But she commended Cianbro for maintaining a schedule and trying to be accommodating.

"It's definitely a relief. It's very exciting to have it completed and overall, it adds to the area, showcasing how beautiful our town is," Walsh said.

At The Spice and Tea Exchange, a downtown shop near the bridge, employee Roo Bosco said work has been going on since the shop opened last summer.

"We've really built a good relationship with the workers," she said. "But we're very excited to have the street back, open parking spaces and the people back downtown."

Businesses on both sides of the bridge are gearing up for the Spring Stroll on May 4, in part a celebration of the near end of construction and a chance for residents "to reconnect with the beauty of historic Downtown Mystic and enjoy a hassle-free day of shopping, dining, and entertainment for the whole family," according to a press statement.

"The focus is Mystic is back open for business," Walsh said.

As for some of the empty storefronts that dot the downtown, Walsh said, building owners have plenty of interest from potential merchants but want to ensure any new business isn't going to complete with existing businesses.

"I think they will have no problems filling them," she said.

Church has been working on the bridge since the winter of 2010, when the first phase of the three-year project began. All work was done in phases during the winter months to minimize any disruption to the tourism season.

Along with structural work, rehabilitation included blasting and painting, realigning the bridge and replacing all of its mechanical and electrical components.

g.smith@theday.com