CME provided the analysis and design work for the replacement of this circa 1935 structure that had reached the end of its service life. The proposed solution included minor widening of the bridge structure, while reusing the existing abutments. The superstructure is comprised of an adjacent prestressed concrete voided slab, with scour improvements that incorporate safe fish passage. CME also provided daily on-site construction inspection and management for the duration of construction.
The project involved a 24 ft. single-span bridge built in 1935 and previously rehabilitated in 1987. The structure consisted of a reinforced concrete deck supported on three concrete tee-beams and one steel rolled beam with concrete abutments and wingwalls. A biennial bridge inspection (conducted by the State) determined that its beams were in serious condition and that the bridge was scour-critical.
These determinations made the bridge a priority for replacement and funding assistance was granted to the Town of Andover through the CTDOT Federal Local Bridge Program. Because the road had one point of entry and provided the only access for residents and a day camp on the far side of the river, it was critical to maintain safe, continuous passage for those impacted. The Town hired CME to perform preliminary engineering and develop the best course of action to rehabilitate or replace the bridge. The study concluded that the abutments were salvageable, but the superstructure would need a full replacement.
CME prepared design plans for the installation of a new superstructure. The abutments, dating from 1935, were integrated into the design with minor repairs and modifications to the existing wing walls to allow for widening of the structure. Due to insufficient roadway width for staged construction, a temporary widening had to be in place before much of the construction began. CME’s solution was to widen the bridge temporarily using elements of the proposed precast sections and the existing bridge. This solution not only saved time but was also cost effective as it reduced the need and cost associated with constructing a full temporary bridge. The new span is comprised of adjacent prestressed concrete voided beams.
In addition, CME designed scour countermeasures consisting of sheeting driven into the channel along the footings for the length of the abutments and wingwalls with concrete tie-backs connecting the sheeting to the existing abutments. Channel backfilling with reserved natural streambed material preserved the natural habitat and promoted passage of native fish species.
Our team also provided site survey and base mapping; developed design for roadway improvements; provided public outreach to review the project, process, and funding; and prepared all necessary permit applications. Our staff also assisted with bidding and utility coordination and provided full-time construction inspection and administration services while the bridge and roadway were being rebuilt.