The bridge that passes over Great Brook on High Street is in poor condition and needs to be replaced, according to a presentation from Quantum Construction Consultants to the Antrim Select Board Wednesday afternoon.

QCC President Rick Wolf Jr. and Vice President and Chief Bridge Engineer Anna Giraldi have completed an engineering study on the site.

“The concrete is starting to fall, there’s severe corrosion and rust,” Wolf said. “The abutments have also experienced some settlement.”

Wolf said there is the potential for voids to form in the roadway, and he and Giraldi explained that the watershed, including Gregg Lake and Great Brook, is about 10 square miles and “there’s quite a bit of flow going through,” Giraldi said, and it’s moving quickly. 

The consultants are proposing three options for replacing it at three different price points. 

The first option is a precast concrete rigid frame founded on concrete pedestal walls that would cost around $1.47 million. The second option is a precast pre-stressed concrete slab with concrete abutments for $1.6 million, and the third option is a precast concrete box culvert that would cost about $1.8 million, which Giraldi said would be trickier to install. 

The consultants said the bridge being in poor condition is a qualifying factor for receiving 80 percent funding from the state through the State Bridge Aid Program. The other 20 percent would come from the town. 

If approved for funding, Wolf said the state eventually reimburses municipalities 80 percent of design and construction costs.

Wolf and Giraldi said all three models would last 75 to 100 years with regular routine maintenance. They hope to move into the design phase and if everything goes to plan, they will have the final design by late spring or early summer of 2024 and construction of the bridge would occur over a 10-month period, starting in the fall of 2024 or the winter of 2025.

The project would be bid on, and when asked what impact winter would have on construction, Giraldi explained that although working in the cold can be more challenging, it can sometimes be cheaper to complete a project like this in winter when construction companies have less work. Most of the bridge structure is precast in an indoor environment.

The Select Board also discussed an article on their warrant that proposes borrowing $600,000 to connect the new well to the distribution system and for the replacement of the main water line under the Contoocook River. In 2021, the town approved borrowing approximately $2.1 million for the project. Since then, inflation and material availability have caused costs to increase. If the additional funds are approved this year, the project would cost approximately $2.7 million.

Antrim would receive $989,280 in principal forgiveness from the Drinking Water State Revolving Fund, and the bonded amount would be ap proximately $1.76 million.

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