This six panel truss bridge is a rare example of a pin-connected truss bridge that is skewed. Skewed truss bridges were far more common during the period where riveted connections were being used on truss bridges.
The bridge has end posts composed of paired angles with v-lacing and cover plate measuring roughly 14 inches wide by 10.5 inches deep. The bridge retains original lattice railings, 24 inches in height. The bridge's vertical members consist of back-to-back channels with v-lacing and are approximately 12.5 inches by 6 inches.
This bridge, although cast aside as "not individually eligible" for the National Register by the Historic Bridge Inventory, is in fact a contributing structure to the Smith/Wallis Gristmill Historic District, and through this fact is considered "officially" historic.
The good news is that this bridge is currently slated for a rehabilitation. This would make it one of an extremely small number of historic pin-connected truss bridges in Pennsylvania to be rehabilitated rather than replaced. It is hoped that this represents a change of attitude in Pennsylvania toward historic metal truss bridges. The only concern with this proposed project is the quantity of original materials proposed to replace, in particular the replacement of all vertical members and diagonal members, which are visually defining features of the historic bridge. It would be nice to see these members simply repaired, and perhaps if needed, spliced with sections of replacement beams, rather than replacing them outright. Also, it would be nice to see the original railings left in place behind a safer modern railings, rather than removed. See the Determination of Effect report link at the top of this narrative for details.
The Historic Bridge Inventory lists the bridge as individually ineligible for the National Register of Historic Places on account of section loss on the bottom chord. With the exception of extreme deterioration or damage where entire sections of a bridge are missing (therefore providing an incomplete picture of what the original bridge looked like), the physical condition of a bridge should not be an excuse to find a bridge that otherwise has historic value as ineligible for the National Register. As such, this finding in the inventory goes against good practice. Also, recent advances in historic bridge restoration techniques, such as pad welding eyebars for section loss, demonstrate that even advanced section loss does not always require total replacement of the affected member. Therefore, issues such as section loss should not normally be a consideration in terms of significance. Further, this bridge's bottom chord section loss is bad, but in reality not that much worse than the many 100+ year old truss bridges that have never had a comprehensive preservation project. Indeed, the bridge remains open to traffic, suggesting that the section loss is not as bad as the many historic truss bridges which have been closed to traffic due to excessive section loss.
The bridge has 9-70 painted on it, suggesting the bridge was painted in 1970, which in 2010 when the bridge was photo-documented was 40 years. 40 years is a very long time to go without painting a metal bridge, and in the long run will cost taxpayers more, either through a more costly rehabilitation, or a complete replacement.
The historic bridge inventory fails to acknowledge the significance of a pin-connected truss bridge that is skewed. These are quite uncommon, and they are representative of a more significant engineering, fabrication, and erection effort.
Information and Findings From Pennsylvania's Historic Bridge Inventory
Discussion of Bridge
The 1904, skewed, one span, 113'-long, pin connected, six panel, Pratt thru truss bridge is supported on stone abutments with flared wingwalls. The trusses are traditionally composed with built up box section upper chords, verticals of angles with lacing, and diagonals and lower chords composed of eye bars. The floorbeams are suspended from the pin by pin plates that are framed into both the ends of the floorbeams and the bottoms of the verticals. To compensate for deterioration at the lower ends of the verticals, U-shaped hangers over a batten plate at the bottom of the verticals were added at an unknown date. The hangers were replaced in kind in 1995. Many rusted lower chord eye bars were observed. The original lattice railings are inside the truss lines. The bridge is a late example of its type and design, and there is so much rust that there is significant loss of original fabric. It is not individually significant in comparison with the varied and deep regional population of complete and earlier pin connected truss bridges. Over 30 examples predate this one.
Discussion of Surrounding Area
The bridge carries 1 lane of a rural road over a stream at a small cluster of 19th century houses and a water-powered frame mill, all of which are east of the bridge. The farm houses are both undistinguished and altered. There are many outbuildings. The west side is a wooded ridge. The area does not appear to have historic district potential. On the whole, the cluster does not possess the architectural significance to be a historic district.
Bridge Considered Historic By Survey: Yes
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