River Road Bridge

Information and Findings From New Jersey's Historic Bridge Inventory

Discussion of Bridge

Summary: The pin-connected Pratt thru-truss bridge is supported on ashlar abutments with stone wingwalls. The south abutment has a toe wall. The members are composed of toe-out channels with lacing and cover plates, and eyebars, a few with welded bars from 1936. A sub-diagonal was welded in the end panels, built of channel sections and batten plates, and welded railings were added. The bridge is a significant, well preserved example of its type. It is one of 4 noteworthy thru truss spans in the county.

Physical Description: The 118'-long 6-panel half-hip Pratt thru truss bridge with pinned field connections is supported on ashlar abutments with concrete toe walls. While the end panels have been strengthened with welded additional members (hangers, diagonals, chords, and subdiagonals) and corner bracing has been welded to the upper lateral braces at the verticals, the trusses are otherwise relatively complete. The inclined end posts and top chord are built up box members composed of channels and cover plate while the verticals are toe-out laced channels. The diagonals and counters are bar stock with both looped and stamped eyes. The bridge exhibits no unusual or patented construction details, but it is a complete example of a traditionally composed pin-connected span with integrity of setting.

Historical and Technological Significance: The pin-connected Pratt half hip thru truss bridge is a late and altered example of its design, but it is one of only two (2100718 is the other example) that remain in the county, and it is thus significant as a rare survivor of a once common type (Criterion C). County records indicate that it was erected in 1901, but the fabricator is not known. Alterations are limited primarily to the end panels where additional members were welded to the original hangers and diagonals to strengthen the span. A subdiagonal was also added. This work was done in 1936. A total of four (2 Pratts, 2 double intersection Warrens), thru truss bridges survive in Warren County (2102307, 2102015, 2160153, 2100718). Three were built by the county, and one was erected by the Lehigh Valley Railroad to carry a local road over its right-of-way. Because of the scarcity of these once common bridge types in Warren County, all four of the thru truss bridges were evaluated as significant because they are rare local examples of a structure type that played an important role in the historical development of the county. The Pratt truss became the most popular of the many truss designs that were experimented with in the 1870s. It was favored because of its overall simplicity, economy of material, ease of fabrication, and strength. The Pratt truss played a significant role in the general acceptance of metal truss bridges for highway use in the last quarter of the 19th century, and by 1900, it was the most common pin-connected bridge type in the nation in both the high and low truss designs.

Boundary Description and Justification: Because it is the span itself that is evaluated as significant, the boundary is limited to the superstructure and substructure of the bridge itself. While the surrounding rural and undeveloped acreage provides an appropriate setting for the bridge, it does not contribute to its significance.

Discussion of Surrounding Area

The bridge is located in a rural area, adjacent to working farms. The one-lane bridge carries a winding local road over a creek. The
Belvidere-Delaware RR has a bridge crossing the creek just downstream.

Bridge Considered Historic By Survey: Yes