"BIBLIOGRAPHY: Hunterdon County Engineer's Office, Bridge Card L140. Hunterdon County Master Plan: Sites of Historic Interest, 1979. Darnell, Victor C. A Dictionary of American Bridge-Building Companies, 1840-1900. Washington, D.C.: Society for Industrial Archeology, 1984.
PHYSICAL DESCRIPTION: The seven-panel, pin-connected, full hip Pratt truss bridge is remarkably well preserved. The top chord is composed of channels, toe out and cover plates with lacing. The bottom chords consist of stamped eyebars. Verticals are composed of channels with lacing on each side. The diagonals are stamped eyebars while the counters are rods. The portals are latticed with A knee bracing. Floor beams are hung using U-bolt hangers. The original lattice web railings remain. The bridge is supported on ashlar abutments with wingwalls finished with pipe railings. According to county records, the abutments were repaired in 1967 and the wingwalls were re-pointed in 1975. The corrugated steel deck with asphalt overlay was added in 1970. Lateral bracing has been welded to the top chords, and knee bracing has been welded to each vertical and lateral brace.
HISTORICAL AND TECHNOLOGICAL SIGNIFICANCE: The nearly unaltered pin-connected Pratt thru truss bridge is the only documented example of the work of a small New Jersey fabricator, Tippett and Wood (criterion C). According to Victor Darnell, this Phillipsburg (Warren County) firm was established in 1868 and operated until at least 1901. Although the bridge does not exhibit any unusual design details, it is a well-preserved example of an important late-19th century bridge type. Its significance is enhanced by the fact that it is documented as being the work of a little-known local fabricator. The bridge, located adjacent to a well-preserved Hoffman home dating to the 19th century, enjoys integrity of setting and design."
I am concerned that this bridge is rated for a bigger load than it ought to have.
Cars and trucks come down the hill and across the bridge at 40-50mph, when they should be doing 15. The sight line is nice and long, so you can see from either side whether another vehicle is coming the other way. When the coast is clear, cars just zoom across the nearly two lanes wide bridge.
Rated at 16 tons, I was on the bridge when a 4 ton truck crossed at perhaps 35mph, and the bridge was shaking considerably.
This is a nice little old bridge, but it does NOT appear to be built or modernized to handle this kind of load. Compare this one to the much heavier built Rockafellows Mills bridge at the other end of the county, (http://bridgehunter.com/nj/hunterdon/10RQ164/) a similar width, height, and style bridge 40% longer that was originally rated at 3 tons and got a magnificent upgrade renovation that really does allow it to handle 16 tons - but at 15mph, not 50.