St. Cloud Railroad Bridge

View an article discussing the strengthening of this bridge

Located immediately upstream of the St. Germain Street Bridge, this large deck truss bridge carries the former Great Northern Railway over the Mississippi River. The first bridge at this location was constructed in 1872, and consisted of two 172-foot and two 170-foot Howe wooden deck truss spans, set onto stone substructures. The substructures were constructed of granite quarried near Rockville, Minnesota; and were constructed by Andrew DeGraff & Company, which completed a large amount of railroad construction in Minnesota. American Bridge Company of Chicago constructed the wooden trusses. When completed, the bridge was heralded as being "one of the finest bridges in the west". Wooden trusses were often used for early railroad bridges, as timber was a relatively cheap material, and the weight of trains permitted this design.

As part of an effort to upgrade bridges, the original wooden bridge was replaced by a new steel bridge in 1892. This new bridge would consist of two 172-foot and two 170-foot, 9-panel, pin-connected Pratt deck truss spans, reusing the stone substructures from the previous bridge. The truss spans were fabricated by the Edge Moor Bridge Works, which fabricated a number of truss spans for the GN. As originally constructed, the truss spans used a standard design for the era, with light built-up vertical members, built-up endposts and upper chords, and eyebars for the lower chord. The floorbeams would be constructed of plate girders, and plate girders were used for the stringers. Above the end panels of each span, the stringers would be continued, with a steel bent placed at the end of each span. Pratt trusses were arguably the most common railroad truss bridge design in the late 19th Century, as they were simple, economical and relatively strong.

By 1922, the bridge had become too light for the heaviest locomotives. Instead of replacing the bridge, the decision was made to strengthen the bridge by adding an additional truss line to each span. The new truss line was fabricated by the American Bridge Company, and was erected by the Guy Willard Company. In addition, the tops of the piers and abutments were reconstructed with concrete to replace damaged stones. During this era, the GN strengthened numerous truss and girder bridges using the same methods. The GN preferred to strengthen large truss spans, as replacing the spans would cost more and be more complicated. Further repairs were made in 1944, when the western pier was encased in concrete. Currently, the bridge is still open to traffic and occasionally carries a train. Overall, the bridge appears to be in fair condition, with no major deterioration noted. The author has ranked the bridge as being highly significant, due to the large scale truss design, age and unique rehabilitation.