During years surrounding 1900, Allegheny County, first under the direction of County Engineer Charles Davis, was busy throughout the region building stone arch bridges of a simple and similar design. These bridges exhibit the many common design features -- parapets with rounded top, horizontal curves at the portals, and similar stone finishing. Most structures may be attributed to Allegheny County Department of Public Works, c1870 - c1925. Though many have been lost to development and road improvements, structures similar in design may still be found in rural locations in the county.
Several bridges have a builder's tablet at the midpoint of the sidewall facing traffic. On older structures the tablet often identifies Charles Davis as the Engineer for Allegheny County. These bridges were built just prior to and during the rise of the automobile.
In some locations, Davis built girder spans which have abutments that share similar traits of his stone arch bridges. A listing of these girder bridges may be found below.
Charles Davis (1837-1907): City Engineer of Allegheny (City) 1867-1875; Allegheny County Engineer, 1881-1907. Davis was involved in surveys to locate Western Pennsylvania Railroad [PRR] and Pittsburgh & Lake Erie Railroad. He was the Engineer during the development of West Park in Allegheny City (North Side). Between his service with Allegheny City and Allegheny County, Davis was consulting engineer on the first Point Bridge (1875-77) over Monongahela River and Engineer on the first project to replace Roebling's Smithfield St Bridge (1880). In addition to road and bridge projects, Davis supervised construction of Henry Hobson Richardson's Allegheny County Courthouse. [Charles Stratton Davis, no relation, is noted as Engineer for the Washington Crossing Bridge completed over the Allegheny River in 1924.]
James Graham Chalfant (1869-1922) was elected to the position of County Engineer in 1907 and served until his death in 1922. Prominent structures during this period include the Manchester Bridge over the Allegheny River and the original Sewickley Bridge over the Ohio River. Lesser structures during Chalfant's direction seem to be lacking a builder's plate or when one is present only the bridge's official name and construction date are shown. Because of this, it is uncertain which of the stone arch bridges may be attributed to him. About this time, the bridge designs were changed structurally to be built as a filled concrete arch with a coursed stone outer face; the aesthetic design was also altered to feature stepped voissoirs, instead of the concentric intrados and extrados typical of most arches. One of the largest stone-faced arch bridges is the 1915 Burchfield Rd over Pine Creek in Shaler.
Vernon Royce Covell, deputy to Chalfant, assumed the position of County Engineer upon the death of Mr. Chalfant. Under Covell's tenure many of the largest bridges in the region were constructed. Additionally, there were a final few stone arch and stone-faced bridges constructed. These later bridges by Chalfant and Covell exhibit further refinement in stonework with a style that is clearly different from the rustic crossings built by Mr. Davis.
Many of these stone arch bridges may be in danger of demolition and replacement. PA Senate Bill 166 P.N. 445 lists the appropriations by county for construction. The bill shown on-line is dated 1997; some of the projects have been completed, while many others may soon be undertaken. In some locations, the old bridges have been or may be bypassed by newer crossings -- but in others it seems any replacement would destroy the older structure. In the latter instances, the replacement is commonly an architecturally-void culvert.
Beginning about 1910 -- after Chalfant assumed the position of County Engineer -- new county bridges were being constructed solely in concrete using a design which mimicked the earlier stone arches. To help in the comparison and understand the transition, a sample of these simple short-span concrete structures is listed below.
