WESTPORT, Conn. (November 1, 2013) – After enduring several months of road closures and traffic detours, the commuters of Westport can celebrate the official opening of the North Avenue Bridge.
The completed North Avenue Bridge, which crosses the Aspetuck River, was widened by six feet to allow for two 12-foot wide travel lanes and a new four-foot wide sidewalk. A new water main and fire hydrant were also installed to service the nearby community.
Diversified Technology Consultants (DTC) was brought onboard to design the new bridge, as well as ensure the bridge achieved flood management certification.
One of the challenges engineers faced was determining how to repair the structurally deficient superstructure. The replacement superstructure needed to be something which could be constructed in the least amount of time to minimize the time the detour was required, yet be cost effective.
After performing hydrologic and hydraulic evaluations in the river, DTC engineers determined enhancements were needed to protect the structure from river scour and to create a viable fish habitat during periods of low flow.
Engineers came up with a three-part process to correct the problem:
1. The structurally deficient steel beam and concrete deck was replaced with a precast concrete box beams and concrete deck.
2. An articulated concrete block revetment system was installed directly in the stream bed to prevent scour. The block revetment was covered with natural channel soils to minimize impacts to fish and other organisms in the stream.
3. A rock weir was installed in order to help reduce bank erosion and to provide a tranquil pool for fish migration.
All work in the stream bed was performed under the guidance of the Connecticut Department of Energy and Environmental Protection Inland Fisheries Division.
“The Aspetuck River at this location experiences high river velocities, making the bridge susceptible to failure due to scour. The addition of the block revetment and rock weir provide necessary scour protection, while still being sensitive to environmental concerns,” said DTC Civil Engineering Manager, J. Andrew Bevilacqua, PE.
The $980,000 project was contracted under the federal local bridge program and all construction was administered by the State of Connecticut Department of Transportation.
The bridge was shut down in March and reopened on Thursday.