Smithfield Street Bridge

The current Smithfield Street Bridge is the third at this location. The first one, a covered wooden bridge, was built in 1818 and replaced a ferry. It was the first river crossing bridge in Pittsburgh. The bridge was destroyed in the Great Fire of 1845 and was replaced by a wire rope suspension bridge designed by John Roebling, who would later build the Brooklyn Bridge in New York. The new bridge, which opened in 1847, was operated as a toll bridge until it was purchased by the city of Pittsburgh in 1895.

Increasing traffic caused the second Smithfield Street Bridge to sway heavily, eventually leading to its closure. In 1881 the company responsible for operating the toll bridge selected a plan for a new bridge submitted by engineer Gustav Lindenthal, an Austrian immigrant.
Lindenthal built a now rare lenticular truss bridge with two 360ft spans. Its total length is 1184ft (361m). The Smithfield Street Bridge initially only had one lane, but in 1889 a second deck was added, doubling its size. The deck contained a double track of rails for horse drawn streetcars, but those were removed between 1994 and 1996 when the bridge was completely renovated. In 1899 the deck was widened to accommodate electric streetcars.

The current steel portals, designed by Stanley L. Roush, Pittsburgh's city architect, were added in 1915 and replaced earlier, elaborate wrought iron portals. While colored gray for most of its life span, the bridge was repainted during the 1994-1996 renovations in the original colors: sandstone-yellow portals with royal-blue trusses (hence it is often called 'blue bridge').

The Smithfield Street Bridge is the longest bridge of its type in the U.S. and the oldest bridge in Allegheny County. Its special construction and historic significance resulted in its designation as a National Historic Civil Engineering Landmark.

For more information on bridges in Allegheny County, have a look at this site.