The Mahoning Avenue Viaduct carries Mahoning Avenue over the Shenango River and railroads in New Castle, Pennsylvania. Built in 1923-24, it replaced the circa 1890 Gardner Avenue Bridge that had been destroyed in a flood in 1913.
Funding was finally secured in 1923 and construction began shortly after. Designed by John Farris and Thomas A. Gilkey, the new 1,195-foot bridge was constructed by the Independent Bridge Company of Pittsburgh with three Pennsylvania through trusses and eight deck plate girder approach spans. The new Mahoning Avenue Viaduct was dedicated on December 18, 1924.
In 1940, the bridge deck over the Shenango River was replaced with a reinforced concrete slab.
On May 15, 1957, part of the bridge deck collapsed on an approach span resulting in its immediate repair. Work began in late 1958 to remove most of the bridge deck and to replace girders that had warped. It was not until fall 1960 that the disputes in funding were resolved. Conn Welding finished the repairs and the bridge reopened on October 7, 1961.
The crossing underwent renovation again in April 1986, reopening on August 30.
A major rehabilitation project by the Pennsylvania Department of Transportation began on the Mahoning Avenue Viaduct in May 16, 2016. The two-year project includes the repainting of the bridge, the replacement of bearings, and substructure and steel repairs, the installation of a LED lighting system and new pedestrian railings.