This bridge is the only surviving pony lenticular truss bridge in Pennsylvania. The few other lenticular truss bridges left are all through truss bridges. Nationwide, all surviving lenticular truss bridges should be considered extremely rare and historically significant. However, as the last pony truss example in Pennsylvania, this bridge enjoys even more historic significance on a state level. This particular example has been left in place for non-motorized traffic only. The bridge provides access to a park area.
Prior to an on-site visit by HistoricBridges.org, the status of this bridge was largely unknown to the historic bridge community and other historic bridge websites on the Internet. The on-site visit confirmed the status of the bridge, however weather conditions included the last half hour of daylight and a nearby strong thunderstorm which had just passed over and was still generating lightning. Elaine Deutsch visited the bridge in better conditions a year later in 2011 and took additional photos for HistoricBridges.org.
Suggested future preservation work for this bridge would be the removal of the ugly solid wood panel railings on the bridge which cover up over half of the beautiful and historically significant lenticular trusses. It is a mystery why anyone would want to cover those up. Numerous alternative railings exist that do not disrupt the view of the truss but also provide an acceptable level of safety. Repair and replication of the cast iron caps would also be worthwhile for the sake of historic and aesthetic integrity of the bridge.
Information and Findings From Pennsylvania's Historic Bridge Inventory
Discussion of Bridge
The one-span, 81'-long, 5-panel, pin-connected, metal lenticular pony truss bridge built ca. 1890 has built-up upper chord, end posts, and verticals, and eye-bar diagonals and lower chord. Built-up fishbelly floorbeams support steel stringers and a wood deck with wood railings inside of the truss lines. The bridge has been altered by the addition of extra diagonals in the second and fourth panels and plate welded to the upper chords and end posts (ca. 1960). The alterations are noteworthy but not considered significant enough to adversely affect the integrity of the rare bridge type and design. Lenticular truss bridges were a patented design of the Berlin Iron Bridge Co. of Berlin, CT. The company fabricated and erected hundreds of lenticular truss bridges throughout primarily New England and New York from the late 1870s to 1900. Pennsylvania was not a major market for Berlin Iron Bridge, but the company did erect a modest number of bridges in the state, especially in some northern tier counties. No less than five lenticular truss highway bridges from 1878 to 1900 have been identified in Pennsylvania. Surviving examples document a historically important variation in late-19th-century metal truss bridge technology.
Discussion of Surrounding Area
The bridge has been closed to vehicular traffic and has been converted to a pedestrian bridge that provides access to a linear municipal park and bikepath bordering the west bank of Little Juniata Creek in Duncannon. At the northeast end of the bridge is a mixed-use commercial and residential neighborhood of late-19th to early 20th century buildings.
Bridge Considered Historic By Survey: Yes
This bridge is tagged with the following special condition(s): Reused
Coordinates (Latitude, Longitude):
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