Bridge 2, located along VT Route 117 (River Road) over the Alder Brook in the Town of Essex, is a corrugated metal pipe arch that was built in 1993. The existing structure is 17-feet wide and is significantly deteriorated with much of the invert rusted out. It is also experiencing major piping and erosion issues. The subject project will replace the existing structure with a new bridge that meets or improves upon all current design standards.

In 2013, the invert of Bridge 2 was determined to be in critical condition with immediate repair action required. The invert began to buckle upward causing heavy settlement in the roadway. Pre-stressed concrete beams were installed over the existing culvert as a temporary bridge for a remedial action.

VTrans evaluated alternatives for rehabilitation or replacement of the bridge in an engineering study completed in June of 2016. The study investigated the design criteria for the bridge and roadway alignment, Right-of-Way impacts, hydraulic, and environmental impacts. Several alternatives were considered including no action, culvert rehabilitation, and full bridge replacement. Given the condition of the structure and the temporary concrete beams, the engineering study concluded that both structures be replaced with a new bridge structure with phased construction.

The new structure will be a buried structure that will meet necessary hydraulic requirements. This will replace the existing deteriorated pipe arch with a dependable and durable structure. A buried invert will protect the culvert from abrasives, and a larger structure width will provide decreased flow velocities. The buried structure will have deep foundations that will prevent any future scour concerns. Additional roadway work will also improve the project site and promote better drainage in the vicinity.
Traffic will be maintained during construction as the new structure is constructed with phased construction. The width of the road and size of the existing structure will provide enough clearance to accommodate two lanes of traffic during construction while one half of the new structure is built. Once half the structure is built, traffic will be switched over and the other half of the structure built. It is not anticipated that any temporary traffic control devices will need to be installed during the phased construction.