www.PDHonline.com - Your Gateway to Lifelong Learning   |   Email: PDHonline@Gmail.com   
PDH Online Course Description PDH Units/
Learning Units (Hours)

Buy Now

View Course

View or Take Quiz


The Bridges of Allegheny County

Jeffrey Syken

Akin to Manhattan with its myriad of bridges, the City of Pittsburgh is surrounded by water obstacles on three sides, but rather than having a north-south orientation as does Manhattan, Pittsburgh has an east-west orientation. To the north flows the mighty Allegheny, which originates in New York State. The fact that Allegheny City lay directly across from Downtown Pittsburgh naturally led it to having more bridges than any of the other rivers. To the south lies the Monongahela (a/k/a the “Mon”). Given the industry along its shores and its lesser current, it became Pittsburgh’s “working river”. In 1818 a wooden-covered bridge across the Mon became Pittsburgh’s first bridge (Pittsburgh itself became a city in 1816). The confluence of the Allegheny and the Mon forms one of the nation’s great rivers – the Ohio (“Good River,” in the native Seneca Indian language). The “Point” formed by this confluence was a/k/a by the native Indians as “The Forks of the Ohio.” Joining the Mississippi River at Cairo, Illinois, the Ohio, with its long length and navigability, became a natural “highway” for settlers heading west and it made Pittsburgh their natural “jumping-off” point.

Looking at a topographical map of Pittsburgh and its environs it becomes clear why Pittsburgh has come to be known as “The City of Bridges.” Up until 1908, the City’s bridges followed the development of the city rather than encouraging it. In fact, the history of Pittsburgh and the County it’s a part of is a showcase of the evolution of bridge technology. Save for movable bridges, Allegheny County has every type of bridge. As technology advanced, so too did Pittsburgh’s bridges. In fact, the story of Pittsburgh’s bridges is not just of those that are currently in-place, but of those that preceded them. When bridges were destroyed by fire or flood, became structurally deficient due to increased loads they were required to carry, from decay or removed as hazards-to-navigation, they were replaced with more modern, up-to-date bridges. A good case-in-point is the Smithfield Street Bridge, which began life in 1846 as a suspension bridge and remained in operation while a new, expandable Pauli (a/k/a “Lenticular”) truss bridge was built in 1880 above it (it remains in operation to the present-day). The industry surrounding Pittsburgh also required many railroad bridges and, in fact, the first crossing of the Ohio River was by a railroad bridge, in 1890.

Pittsburgh was/is also a mecca for many of the great bridge builders, past and present, including the creators of the Smithfield Street Bridges; John Augustus Roebling (1846 suspension bridge) and Gustav Lindenthal (1880 truss bridge). In particular, Roebling, of Brooklyn Bridge fame, fine-tuned his craft as a bridge-builder extraordinaire in the Pittsburgh vicinity during the mid-19th Century, with several bridges (including an aqueduct) to his name. With the advent of the “City Beautiful” movement and the creation of Pittsburgh’s Municipal Art Commission (in 1911) along with the Federal Rivers and Harbors Act of 1899, a sea-change in the design and construction of Pittsburgh’s bridges occurred in the late 19th and early 20th Centuries. In particular, the maturation of reinforced-concrete arch-type bridges prevailed in Allegheny County, culminating in the George Westinghouse Memorial Bridge over the Turtle Creek Valley, opened-to-traffic in 1932. However, the story of Allegheny County’s bridges is not just of its bridges, it’s a story of constant vigilance to keep them in safe operating order so that tragedies such as the collapse of the Fern Hollow Bridge, in January 2022, are not repeated.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

View Course Content

NY PE & PLS: You must choose courses that are technical in nature or related to matters of laws and ethics contributing to the health and welfare of the public. NY Board does not accept courses related to office management, risk management, leadership, marketing, accounting, financial planning, real estate, and basic CAD. Specific course topics that are on the borderline and are not acceptable by the NY Board have been noted under the course description on our website.