The Maine Department of Transportation contracted Kleinfelder for the preliminary design, final design, and construction administration for the replacement of aging and deteriorated twin concrete box culverts. During the preliminary design, Kleinfelder carefully compared various design alternatives that considered the many challenges at this site. Construction of the replacement structure was completed in the spring of 2012.
One of the biggest challenges on this project was to determine a cost-effective solution that satisfied all impacted stakeholders. Key stakeholders included commuters that needed continued access during construction. Environmental agencies also wanted to ensure alewife migration was uninterrupted during and after construction. The project also involved coordination with the Federal Highway Administration, which led to design constraints but also innovative opportunities.
Two concrete box culverts (12-foot span by 7-foot rise; 12-foot span by 5-foot rise) with beveled ends were selected as the preferred alternative. Staged construction allowed for one lane of traffic in each direction to occur throughout construction. A strategic construction sequence using the existing and new box culverts was essential to maintaining downstream flow at all times. The replacement structure included sediment retention sills along with one foot of natural streambed cover to facilitate seamless fish passage for this important waterway.
The Kleinfelder team successfully collaborated with all key stakeholders to determine and implement a solution that satisfied all interests. The result was a cost-effective concrete structure requiring minimal maintenance while providing seamless fish passage for alewives and other important aquatic species.