Granite Falls Railroad Bridge (South)

Located on the north side of Granite Falls, this truss bridge crosses the main channel of the Minnesota River. The first bridge at this location was constructed in 1887, and consisted of wooden truss spans approached by timber pile trestle spans. It is unclear if this bridge utilized stone piers or timber piers. In 1902, the bridge would be replaced by a new steel bridge. The bridge remained largely unchanged until 2009, when it was separated from the northern bridge by filling much of the timber pile trestle between the steel spans. Currently, the bridge consists of a pair of 144-foot, 8-panel riveted Warren through trusses, approached by a 50-foot through plate girder on the north end and set onto stone piers. In addition, the north end of the bridge is approached by concrete modular girder spans, which are supported by steel pile substructures. Stone for the piers consists of a yellow-pink quartzite, likely quarried near Pipestone, Minnesota. American Bridge Company fabricated the superstructure, and the stone piers were constructed by an unknown contractor.

The truss span follows a standard design for the era, with heavy members, riveted connections and a standard floor system. Both the top chords and endposts use a built-up design, with a solid plate on the top and X-lacing on the bottom. The bottom chord uses a similar design, with X-lacing on both sides. The diagonal truss members both use a heavy built-up design, with X-lacing on both sides. The vertical truss members consist of solid beams. The floor consists of two plate girder stringers, which are connected to plate girder floorbeams at the panel points. The lower lateral bracing consists of solid bars, which form an X-shape. Both the portal bracing and sway bracing follow a standard GN design, with a double intersection lattice design formed out of L-shaped bars. The upper lateral bracing consists of V-laced beams which form an X shape at each panel. Similar to other bridges from this era, the girder span uses two modest sized girders, square girder ends and a standard floor. The piers use a standard rectangular design with angled noses. The abutments use a standard design, with stepped wing walls which extend diagonally from the bridge. The north approach uses a standard design, with hollow precast concrete girders and steel pile piers with a concrete cap.

The Warren truss span became popular around the turn of the 20th Century, as it provided greater rigidity and strength than traditional pin-connected spans. In addition, these spans were economical and simple. This particular design of truss appears to have been a GN standard, as it was used at numerous locations throughout the GN system. Warren truss spans were also among the first to use riveted connections, which quickly became the preferred connection type for truss bridges. Since the 2009 alterations, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in fair to good condition, with little significant deterioration noted. The author has ranked this bridge as being moderately significant, due to the truss design.