The Cavendish Bridge 58 project will replace the existing bridge, which is considered structurally deficient, with a new bridge on the existing horizontal alignment. The existing bridge is located on a substandard sharp horizontal curve; due to site constraints, the new bridge will follow the existing roadway curve. The existing bridge is a two-span concrete T-beam bridge constructed in 1940, and is 87-feet long and 36.8-feet wide. The bridge superstructure (deck and beams) components are in poor condition and the bridge substructure is also in poor condition.

VTrans evaluated alternatives for replacement of Bridge 58 in an engineering study completed in March 2015. The study assessed the proposed design criteria for the bridge and roadway alignment, Right-of-Way impacts, hydraulics, and historic resources. Several alternatives were considered including no action, permanent bridge closure, and full bridge replacement. Given the age of the structure and existing hydraulic and structural deficiencies, the engineering study recommended full bridge replacement with a single span bridge.

The new bridge will be comprised of a superstructure that has the minimum depth possible for the design span, in order to maximize hydraulics. The proposed bridge will include a completely new bridge that is 24 feet wide curb to curb with a 5’-6” sidewalk on the eastern side of the bridge. It is proposed that the sidewalk on the western side of the bridge be eliminated. The proposed structure will match the existing geometry in regards to horizontal alignment, and will be raised three-inches for improved hydraulics. The current structure just meets the minimum hydraulic standards, therefore, the new superstructure span and type should be chosen based on the minimum depth. In order to reduce impacts to historic resources, it is recommended that the new abutments are placed on piles behind the existing abutments. This will eliminate the need for cofferdams, and result in a more economical project. The existing pier will be saw-cut down to the stream bed.