Specifications include, but are not limited to: The Cedar Hill Bridge carries Road 2380 over the Animas River in San Juan County, New Mexico. The location is rural, surrounded by a combination of rocky cliffs, a wash, and farmland. Immediately west and parallel to the bridge is an irrigation flume which carries water over the Animas River. This flume structure is a pin-connected truss composed of members that are similar to those used in the highway bridge, but it has a significantly different overall configuration and appearance because it was purposely designed to serve as a flume. The flume itself is quite unusual and may have individual historic significance. It also compliments the architectural appearance of the highway truss bridge. The single span bridge is approximately 100 feet in length consisting of a five panel pin-connected Pratt through truss. The steel superstructure and deck is composed of the following details: End posts and upper chord: back-to-back channels with cover plate and v-lacing; verticals: back-to-back channels with v-lacing on each side; bottom chord: up-set eyebars; diagonal members: up-set eyebars; counters: loop-forged rods with turnbuckles; Portal bracing: traditional a-frame design composed of angle; upper and lower lateral bracing: threaded rod; sway bracing: paired angles; floorbeams: rolled American Standard Beams; deck stringers: six rows of rolled American Standard Beams, plus two fascia channels; deck: timber; railing: two channels mounted to truss vertical members. The bridge has riveted pin plates which also function as hangers which are bolted to the floorbeams. The truss displays a historical technique used in fabrication shops to produce cutouts of small sections of steel, such as the ends of vertical member channel flanges to make room for eyebar heads. Rather than use a cutting torch or other modern equipment, a series of small holes would be successively drilled in a row to cut the section of material. The use of this technique is readily recognizable by the sawtooth appearance of the area that was cut. The bridge sits on a concrete substructure. The northern end of the bridge has a simple concrete abutment which extends down to the river. A large horizontal crack in this abutment appears to indicate that the abutment was constructed in two concrete pours. The south abutment in contrast is a short section of concrete which rests upon a large rock outcrop along the river.
