New Cushing Road Bridge in Thomaston to be built with fiberglass composite beams

Nov 07, 2023

THOMASTON — Known as the Cushing Road Bridge, and the Wadsworth Street Bridge, over the years, the historical green bridge that spans the Georges River in Thomaston is set to be demolished after a new bridge is constructed right beside it. The Maine Department of Transportation first scheduled the bridge to be replaced in October 2013 and new construction began in November 2014. Construction is expected to take two years, and Guy Hews, resident engineer for the state of Maine, explained why.

"The old bridge is getting completely replaced," said Hews. "The existing bridge will remain in place until the new one is done and open, so as to impact the traffic less."

The new bridge carries a price tag of almost $2.5 million and will use a new type of composite beam construction that's designed from fiberglass. The new bridge will be just upstream of the old bridge.

The new composite materials for construction are considered Space Age design material.

"We’re currently using the exact same construction on the Union Street Bridge in Bangor," he said. "It's also the same material that we used on the Knickerbocher Bridge in Boothbay. It's light-weight composite beams. There's no steel in it — this is basically the concept — for being around salt water and its longevity."

The beams are known as hybrid composite beams (HCB). With each, a glass fiber shell encases a core of foam and high strength, steel fibers.

The Knickerbocher Bridge was the first of its kind in Maine for the DOT.

The beams were constructed by Harbor Technologies in Brunswick, though the design comes from the Richmond-based Wyman and Simpson, according to an article in Maine Biz.

"We have to wait and see," said Hews. "It hasn't been around for 150 years like steel has. We know that works, but it rusts. Laboratory tests show it will last for at least 75 years, if not 100 years."

The existing bridge was completed in 1928 and in its day used two different truss styles. One was a counter weight system that allowed the bridge to be raised and lowered.

The steel sidewalk was added in 1991, at which time the counter weights were removed, rendering the bridge-raising mechanism inoperable. Because of its design the bridge carried some historical significance.

"There's always grief given because people have attachments to things that have been there forever," said Hews. "With this particular bridge, its functionality is outdated. It's just no longer a bridge that can open. The width is narrow and the height is limited. It's posted to only one truck at a time. The new bridge won't be limited. It will be an open bridge, there's nothing above."

The new bridge will be 36 feet wide.

So why is it going to take two and a half years to replace one bridge?

"People drive by the site and they see little or nothing going on," he said. "And they wonder why it would take so long to replace a bridge of this size. It all comes down to the environmental window and the impact in the river."

The environmental window is during the winter because of the species affected.

"The sturgeons and Atlantic Salmon are affected," said Hews. "That window actually ended March 15. We’re not allowed to do any work in the river after that date until next November. We can do all the approach work, the sewers and the abutments this year during the summer season."

Hews said come next November the DOT can put the pilings in the river.

The environmental window limits the amount of work that can be done during that time. Hews said there are old gas storage tanks on the property and they will be removed in the next two to three weeks.

On the back of the property is an old lime kiln that the town wants to preserve.

"The town is currently in negotiations with the state to purchase that piece of property," said Hews. "It is their intent to turn it into a small park."

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