Location:Pittsburgh, PA (view map)
Type: Riveted Parker Truss, with 11 girder spans on trussed bents
Year Built: 1960
Crosses: Norfolk Southern Railroad

The City of Pittsburgh is known for the large bridges crossing its three rivers. Often forgotten and overlooked are some of the smaller bridges along the hillsides, crossing streams, ravines, or railroads. One such bridge is the P. J. McArdle Roadway Viaduct No. 1. P. J. McArdle Roadway, originally known as the Mt Washington Roadway, was first planned in the early 1910's and completed in the 1930's. The roadway was designed connect the South Side neighborhood of Pittsburgh to the Liberty Tunnel and Mt Washington. The new roadway was built provide better vehicular access to the southern areas of Pittsburgh while reducing the dependence on the crowded inclines (funiculars). The new roadway featured three bridges. Viaduct No. 1 along Lower McArdle Roadway (between the South Side and the Liberty Tunnel) was completed in 1933. The bridge is an example of a steel Parker through truss over the Norfolk Southern Railroad, with steel stringer approach spans on trussed bents.

By the 2000's, the bridge became severely deteriorated. In a 2007 inspection, the bridge's superstructure was rated poor (4 out of 9). The substructure was rated critical (2 out of 9). Temporary scaffolding supported parts of the deck along the approach spans. Rather than demolishing the deficient bridge, the City of Pittsburgh decided to rehabilitate it. The bridge was closed to traffic on January 10th, 2011 for a one year, $7 million dollar project. Construction includes rehabilitating and repainting the 215 ft steel truss and replacing the approach spans. The original decorative railings will be restored and reinstalled on the new road deck. Design work was performed by MS Consultants, and construction is currently being performed by M. A. Beech, Co.

Not only will this project take another bridge off of the structurally deficient list, it will preserve the look of the truss bridge nestled along the South Side Slopes for many years to come. Perhaps the rehabilitated bridge will become an attraction of its own, an interesting historic bridge that provides a beautiful vantage point overlooking the City of Pittsburgh. See the Post-Gazette's 360 degree photo from the bridge here.