Kiwanis Bridge

Located on the west side of Rock Valley, this through truss bridge carries a former Chicago, Milwaukee, St. Paul & Pacific Railroad (Milwaukee Road) mainline over the Rock River. The first bridge at this location consisted of a long timber pile trestle span, which was last renewed in 1910. This bridge was prone to flooding and ice jams on the Rock River, and required continuous repairs. In the late 1920s and early 1930s, the Milwaukee Road began upgrading bridges system wide, often using secondhand spans to replace light metal bridges and deteriorating timber bridges. In late 1929, a Milwaukee Road Bridge & Building Department crew arrived in Rock Valley to begin constructing a new bridge. The new bridge would consist of two secondhand through truss spans, set onto new concrete piers and approached by timber pile trestle spans on either end. The bridge was completed in May 1930. Currently, the bridge consists of a pair of 140-foot, 7-panel, pin-connected Pratt through truss spans, set onto concrete piers. The east end is approached by seventeen timber pile trestle spans, while the west end is approached by six timber pile trestle spans. The truss spans were designed by Albert Reichmann and Onward Bates, and were fabricated by an unknown contractor. The Milwaukee Road designed many of their own bridges in-house, and operated a sophisticated Bridge & Building Department to erect the spans and construct concrete substructures.

It is believed that the truss spans were originally fabricated in 1897 and reused from Bridge #Z-312 across Rock River Bridge at Byron, Illinois. That bridge was constructed as part of a double tracking project, and consisted of five heavily skewed 160-foot, pin-connected Pratt through truss spans. The spans of this bridge were unusual, and contained two different truss designs. The outer spans (spans #1 and #5) had normal inclined endposts and were square at the abutments. The inside ends of the outer spans had one inclined endpost and one vertical endpost to account for the heavy skew of the piers. This unique configuration gave a "long" 9-panel, 176-foot truss and a "short" 8-panel, 160-foot truss for each end span. The inner spans (spans #2, #3 and #4) each used an inclined endpost and a vertical endpost on each end, and both trusses were 8-panel, 160-foot trusses. This unusual configuration is shown in photos #66 and #67 above. It is believed that the spans reused here were the outer spans (spans #1 and #5) from the Byron Bridge. Shortening the spans to 140-foot spans would have been accomplished by removing a center panel of the truss and the additional ninth panel from each span, while replacing the inclined endpost at the inside with a vertical endpost from one of the other spans. Empty rivet holes and splice plates at the top chord (photo #58) provide evidence of these alterations. One additional span was known to have been reused from the Byron Bridge, and was installed at Bridge #Q-1444 near Good Thunder, Minnesota.

The truss spans follow a standard design for the late 19th Century, with built-up members, a standard floor and a lattice style portal. The outer endposts consist of an inclined built-up beam, with a solid plate on the exterior and X-lacing on the bottom. The inner vertical endposts use two heavy H-shaped channels, which are connected by thin plates and four columns of rivets. Similar to the outer endposts, the top chord is constructed of a built-up beam with a solid plate on the top and X-lacing on the bottom. At the outer two panels of each span, the bottom chord consists of a built-up beam with X-lacing on both sides, while the inner panels use sets of eyebars. The vertical members use two U-shaped channels, which are connected by thin plates with four total rivets. These members are connected to the ends of the floorbeams by a triangular plate. The diagonal members consist of steel plate eyebars of various sizes, and turnbuckles are present on the counter members. The floor system uses two plate girder stringers, plate girder floorbeams and L-bars for the lower lateral bracing. Unique to this bridge, the floorbeams use a trapezoidal shape, with the outer ends tapered. The outer portal bracing follows a standard Milwaukee Road design, with a deep double intersection lattice beam and curved plates for the heel bracing. The inner portals and sway bracing use a similar lattice beam with angled L-bar brackets. The upper lateral bracing consists of square bars, which are pinned to the top chord by use of a clevis. The piers use a standard design, consisting of large rectangular structures with an angled upstream nose.

The Pratt truss design was arguably the most popular railroad truss span during the second half of the 20th Century. This type of span was simple, durable and economical. By the turn of the 20th Century, railroads began switching to riveted connections and a Warren truss design, which was heavier and stronger without sacrificing cost. Railroads often reused steel and iron spans, as it provided a cost effective way to rebuild bridges without requiring large amounts of new material. The Milwaukee Road operated a sprawling bridge shop at Tomah, Wisconsin; which was capable of repairing and altering bridge spans as needed. It is believed that the truss spans were altered at this location by railroad company forces. The method of shortening the spans was unusual, but was not difficult. Truss spans were designed so that pieces could be substituted or altered as needed. After the railroad was abandoned, the bridge was purchased by the Kiwanis Club in Rock Valley, and converted to trail use by adding a deck and railings. The purchase of this bridge likely spared the structure demolition. Today, the bridge remains a popular piece of the local trail system. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. In particular, the concrete piers and trusses have no major defects visible. The author has ranked this bridge as being regionally significant, due to the truss design and unique alterations.