Abandoned bridge in Ohio

Zoarville Bridge - Dover River Bridge, Zoarville Ohio

Date added: June 09, 2023 Categories: Ohio Bridges

The Zoarville Bridge is the only known example of a Fink through truss bridge still standing in the United States. It is also the sole surviving bridge erected by Smith, Latrobe and Company of Baltimore, and is the only surviving work by Charles Shaler Smith, the company president, who was a prominent innovator in the design of 19th-century American bridges.

The Fink truss was patented in 1851 by Albert Fink, an engineer who worked for the Baltimore and Ohio Railroad. His original design was for a deck truss without a bottom chord. As a modified example of a Fink through truss, the Zoarville Bridge has a reduced number of posts and ties used in its trusses. A true Fink truss would have four additional posts, with ties running from their upper ends to the lower ends of adjacent posts. This bridge is also distinctive for its round iron columns, which are similar to those manufactured by the Phoenix Iron Company of Pennsylvania; for its combination of such columns with flat plates and angles in the end towers; for its foot boxes which permit adjustment of each post's level and the tension in the ties; and for its unusual ornamentation which is integral to the structure. Smith, Latrobe and Company, builders of the Zoarville Bridge, specialized in Fink truss designs and particularly favored use of the Phoenix column, for which Charles Shaler Smith, company founder has been credited with introducing in the construction of railroad trestles.

The principal men of the company which built this bridge were leaders in the American civil engineering profession, and are profiled below. Smith, Latrobe and Company was founded in 1866 with Charles Shaler Smith as president and chief engineer. The firm incorporated in 1869 as the Baltimore Bridge Company, and by 1880 had erected more than 13 miles of bridges, including four over the Mississippi River, one over the Missouri, and one over the St. Lawrence. A Tuscarawas County Commissioners' journal entry for January 29, 1868 (Vol. 4) which enumerates the bids for construction of the "iron superstructure of the Dover River Bridge", includes Smith, Latrobe & Co. of Zanesville, Ohio. An undated (circa 1868) advertising flyer by the company indicates C.D. Caldwell as a special partner in Zanesville. Taken together, these suggest that Smith, Latrobe and Company was particularly active in seeking projects in Ohio, and that Caldwell may have been superintendent of construction on this bridge. Today the Zoarville Bridge is the only bridge constructed by this firm that is still standing.

Charles Shaler Smith, president of Smith, Latrobe & Company, was regarded as one of the greatest American engineers of his day. He entered the engineering profession in 1852, and by 1857 was assistant to the chief engineer of the Louisville & Nashville Railroad. That same year he became an assistant to Albert Fink, of the same railroad. During the Civil War years Smith served as a captain of engineers for the Confederacy, before founding Smith, Latrobe & Company in 1866. Smith was famous for his daring and innovative solutions to difficult engineering problems, such as his employment of the cantilever to dispense with falsework at the Kentucky River Bridge (the first major cantilever in North America). His introduction of a Phoenix column variant, with flat plates sandwiched between the flanges, is reflected in the construction of this bridge's end towers. These towers may have been the basis for a bridge chord design patented by Smith in 1869, in which he substituted I-beams for the plates and angles. The Zoarville Bridge is believed to be the only actual example of this patented technique. Smith was also a director of the American Society of Civil Engineers, obtained numerous patents held by the company, and authored several articles on bridge engineering.

Benjamin Henry Latrobe served as a consulting engineer for Smith, Latrobe from its founding in 1866 until shortly before his death in 1878. From 1842 Latrobe was chief engineer for the Baltimore & Ohio Railroad, and also served as president and chief engineer for the Pittsburgh & Connellsville Railroad, consulting engineer for the Hoosac Tunnel, and membership on the board that reviewed John A. Roebling's plan for the Brooklyn Bridge. Latrobe's most noted achievement was the extension of the Baltimore & Ohio over the Allegheny Mountains, an undertaking many at the time considered impossible.

Charles Hazlehurst Latrobe, son of Benjamin Latrobe, also worked for the Baltimore & Ohio Railroad and served as an engineer in the Confederate army, returning to Baltimore after the war to work as a civil engineer. He designed many of the city's bridges as engineer of the Jones Falls improvement project, and in 1886 was appointed general superintendent and engineer of public works in Baltimore. His most acclaimed achievements were the Arequipa viaduct and the Verrugas bridge in Peru, at the time the highest structure of its kind in the world. These projects were done in conjunction with the Baltimore Bridge Company, for whom Latrobe served as Associate Engineer, Secretary, and Treasurer until at least 1875.

Bridge Description

The Zoarville Bridge is the only standing Fink through truss bridge known to exist in the United States. It was erected in 1868 by Smith, Latrobe and Company of Baltimore, part of the three-span Factory Street Bridge over the Tuscarawas River in the city of Canal Dover. When that bridge was replaced in 1905, this span was moved to its present location over Conotton Creek, in a rural setting near Zoarville, approximately 8 miles northeast of Dover. It replaced a wooden covered bridge on the same site, and was in turn abandoned in the early 1940s after a portion of State Route 212 was relocated to higher ground.

The bridge is 108-foot long x 17-foot wide x 20-foot tall, and is composed of a pair of modified Fink through trusses. Each truss has two end towers, three vertical posts, a number of diagonal ties, and a horizontal upper chord. The floor system of planking, stringers, and cross-beams was probably installed in 1905. The plank decking is now largely rotted, caused in part by periodic inundation within the flood pool of the Dover Dam.

The compression members, comprising the end towers, top chords, and intermediate posts, are hollow structural tubes of curved wrought iron plates riveted together at flanges and fitting onto iron boxes at the joints or panel points. The top chord consists of eight-inch diameter tubes composed of four curved plates, and every post is a six-inch diameter column of three plates; these structural tubes are known as "Phoenix columns." Each end post consists of an eight-inch diameter column of four curved plates with flat plates sandwiched between the flanges. The plate parallel with the span of the bridge extends twelve inches beyond the flanges at the bottom on either side, and tapers up to within 2 1/2 inches at the top. Pairs of angles are riveted to the plates at their edges, giving the effect of a tube bisected by a tapered compound riveted girder.

Diagonal ties, or tension members, are pairs of flat wrought iron bars with eyes at each end that fit over pins passing through the boxes. The posts bear on foot boxes resting on cross beams and hung by loops from pins fitting through slotted holes in foot boxes. Additional struts and ties provide lateral bracing. With the exception of the boxes, which are cast iron, all members are rolled wrought iron or fabricated from rolled pieces.

The cast-iron joint boxes at the upper ends of the posts and the foot boxes at the lower ends are necessitated by the use of the structural tubing. The foot box is part of an assembly that not only transfers loads to the diagonal tubes but also permits adjustment of the tension in those ties and the relative heights or levels of the posts and cross beams. Each post bears upon a foot box, the foot box upon one end of a cross beam, and the cross beam upon a square foot plate, two washer plates, and four nuts. The nuts are turned onto the threaded ends of two roughly V-shaped links or loops hanging on the ends of a pin that fits through vertical slots in the sides of the foot box. The pins also accept the ends of the eye-bar ties. Tightening the four nuts raises the beam, foot box and post.

The upper lateral ties across the bridge between the joint boxes at the tops of the posts are of a unique design, although possibly not original to the bridge. They are cruciform in section, each consisting of two "T"s riveted together. The "T"s are pulled apart at their ends, with their legs between and bolted to pairs of plates which are riveted to flanges of the tubes on either side of the joint box. The diagonal lateral bracing at the top of the bridge consists of round eye-bars, retained at their ends between the plates by through bolts.

Ornamentation on the bridge is restrained and part of the structure rather than applied to it. Each joint box surmounting an end tower features a cornice with dentils. The crest of the portal is pierced by hexagonal and quatrefoil openings, and corner brackets inside the portal form a flattened Tudor arch.

The condition of this bridge is deteriorating. It is subject to periodic inundation of the deck due to the operation of the Dover Dam, approximately 1-2 miles downstream from the bridge. The floor system is supported by flanges on the vertical posts; the webs have rusted away, and the overall condition of the deck is now critical.