CN Manitowoc River Bridge (Valders)

Located west of Valders, this through truss bridge carries the former Soo Line Manitowoc Branch over the Manitowoc River. Constructed in 1896 as the new line was built, the bridge initially consisted of a single through truss span, set onto timber pile piers and approached by timber pile trestle spans. In approximately 1920, the bridge was upgraded with concrete piers, giving the structure its present configuration. Currently, the bridge consists of a 150-foot, 5-panel, pin-connected Pratt through truss span, set onto concrete piers. In addition, the west end is approached by six timber pile trestle spans, while the east end is approached by four timber pile trestle spans. The main span uses a typical design for the era, with lightweight members and a traditionally composed floor. The top chord and endposts are constructed of built-up beams, with V-lacing on the bottoms and solid plates on the exterior. The bottom chord is composed of eyebars, typical of 19th Century pin-connected truss spans. Also similar to other spans from this era, the diagonal members are also composed of eyebars. The hip-vertical members are constructed of solid rolled beams, while the remaining vertical members are constructed of V-laced beams. The portal bracing uses a typical Wisconsin Central design, with a double intersection lattice pattern with angled heel bracing. The sway bracing is composed of lightly V-laced beams. Both the upper and lower lateral bracings are constructed of thin rods which are pinned to the top chord and floorbeams, respectively. The floor uses a standard design, with two plate girder stringers and plate girder floorbeams. Both piers use a standard rectangular concrete shape, and are likely founded on timber piles.

Wisconsin Bridge & Iron Company fabricated the truss span, and it is unknown if the concrete piers were constructed by railroad company forces or by an unknown contractor. This company fabricated all steel spans required for the new WC line to Manitowoc in 1896. Pratt trusses were arguably the most popular truss bridge design during the second half of the 20th Century. These spans were strong, durable, simple and economical. Ultimately, this design was superseded by riveted Warren truss spans in the early 20th Century. Since the initial construction, the bridge has seen a handful of alterations. The most prominent alteration involved strengthening of the truss span, which was completed in the 2000s. Additional transverse beams have been added at the top of the portal, and high strength rods hold this beam to the bottom chord, giving the structure greater strength. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The timber approaches appear to have been renewed in the late 20th or early 21st Century. The author has ranked this bridge as being moderately significant, due to the truss design.