CN Boyer River Bridge #9

Located in Logan, this through plate girder bridge is the ninth and final bridge carrying a former Illinois Central Railroad mainline over the Boyer River. When the railroad originally was constructed, the first bridge at this location consisted of a 91-foot and two 45-foot through plate girder spans, set onto concrete substructures. The Boyer River had long experienced severe floods, and by the early 20th Century it was decided to channelize the river. Originally, the river was channelized in the 1920s and 1930s. By the 1940s, it was decided that several bridges across the river needed to be lengthened or shifted to allow for a wider channel. Several improvements were made to this bridge in the 1950s, including the construction of a new east pier in 1950 and construction of a new west pier in 1953. By 1957, the river channel had shifted slightly south, and it was decided to replace the southernmost span with a larger secondhand through plate girder span, set onto a new concrete abutment. The original 45-foot span was likely reused at another location. During the 1940s and 1950s, several bridges along this line were rebuilt, which allowed for spare spans to be reused at other locations along the line.

Currently, the bridge consists of a 45-foot through plate girder span on the north end, a 91-foot span in the center and an 87-foot span on the south end. Both the center and north spans are original to the bridge, while the southern span was fabricated in 1928 for use at an unknown location. The entire bridge is set onto concrete substructures, and the north abutment is the only portion of the substructures which was retained from the original 1900 bridge. The three spans all use a similar design, with two girders, square girder ends and a standard floor system. Due to the different span lengths, the girders are all different heights. The two piers use a standard IC design for the era, consisting of two concrete columns, connected by an arched concrete beam at the top. It is believed this style of pier was used to reduce material and improve channel flow. The north abutment uses a standard U-shaped design with no wing walls, while the south abutment consists of a standard rectangular structure with short sloped back walls. Scouring near the south abutment has revealed that the abutment is set onto heavy timber piles. American Bridge Works fabricated the north and center spans, while American Bridge Company fabricated the south span. J.S. Patterson Construction Company constructed the north abutment, while the piers and south abutment were constructed by unknown contractors or railroad company forces. Through plate girder spans were popular for railroad use, as they were durable and easy to construct. Since the 1957 reconstruction, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted.