New Kate Shelley High Bridge

Located between Boone and Ogden, this large deck plate girder viaduct was constructed to carry the Union Pacific Railroad mainline over the Des Moines River and Juneberry Road. Between 1899 and 1901, the Chicago & North Western Railway constructed a tall steel viaduct over the Des Moines River at this location to eliminate an inferior route through Moingona. The viaduct was named the Kate Shelley Bridge, in honor of a heroine from Moingona who saved a train from plunging through a failed trestle in July 1881. The original double track viaduct remained in heavy use through the 20th Century. By the 1950s, the viaduct was reportedly only capable of carrying one train at a time. Several repairs were made to the original viaduct, including a significant strengthening of the center span in 2001. By the early 21st Century, it had become clear that the original viaduct was no longer a feasible long term solution. Union Pacific Railroad, which acquired the C&NW in 1995, began planning a replacement viaduct to improve operations on the busy line. In 2004, UP salvaged 23 deck plate girder spans from a former Milwaukee Road bridge across the Des Moines River at Madrid, Iowa. These spans were trucked to Boone, and stacked in the yard for future reuse.

Omaha, Nebraska based engineering firm HDR, Inc. was chosen to design a new bridge located just north of the original viaduct. Earthwork for the new bridge began in November 2006, and consisted of clearing trees and grading space for a second set of tracks on either side of the river. In March 2007, construction on concrete shafts began, with work on the substructures progressing through 2008. The first steel spans were set on the concrete substructures in September 2008. On August 20, 2009; the new bridge opened to traffic. The old viaduct was left intact and disconnected from the tracks on either end. The new viaduct was designed for two trains to operate at a maximum of 70 MPH, which had not been possible on the old viaduct since the mid-20th Century. 56 shafts were required, with some reaching 100 feet deep, to construct the concrete piers. 1,554 tons of reinforcing steel bars, 632 tons of I-beams and steel bracing and 28,000 cubic yards of concrete were used in the new substructures. 4600 tons of structural steel were used for the superstructure. The entire project required 552,000 cubic yards of soil and the total cost of the project exceeded $50,000,000. The bridge was named the New Kate Shelley Bridge, also in honor of Kate Shelley.

The viaduct consists of twenty double track 110-foot deck plate girder spans and six 70-foot deck plate girder spans. The east end is approached by three 30-foot concrete modular girder spans, while the west end is approached by three 30-foot and one 12-foot concrete modular girder spans. The substructures are mainly constructed of concrete, with the exception of the approaches, which use steel piles. All deck plate girder spans use a weathered steel, with the 110-foot spans using extensive ribbing throughout the sides and the shorter 70-foot spans having smooth sides. All twenty of the north track 110-foot girders and three of the south track 110-foot girders were reused from Madrid, Iowa. These spans had originally been fabricated in 1973 as part of a project to construct a new bridge for the Milwaukee Road mainline across the Des Moines River. The original bridge at that location consisted of a tall steel deck truss and deck girder viaduct, which would have quickly deteriorated underneath the waters of the newly impounded Saylorville Lake. The remaining seventeen 110-foot spans and all 70-foot spans were fabricated in 2008-09. The approach spans use a standard concrete modular box girder design, typical for modern railroad bridges. A concrete ballast deck covers the entire bridge. The main bents are formed using two concrete columns, which are connected by transverse beams at the bases and intervals throughout. These columns were constructed by using drilled shafts. Five towers are created by connecting two bents with longitudinal concrete beams at the bases, tops and at intervals throughout. At the ends of the main spans, concrete wall type piers are used, and the approach spans are set onto typical steel pile and concrete cap bents.

HDR, Inc. was chosen to complete the design and construction engineering for the bridge. OCCI, Inc. was awarded the contract for constructing the substructures and erecting the steel spans. The 1973-era deck girder spans had been fabricated by Bennett Industries, which used steel produced by the Bethlehem Steel Company of Bethlehem, Pennsylvania. The remaining deck girder spans were fabricated by the Paxton-Vierling Steel Company. Railroads often reused steel spans, as it provided a cost effective way to construct bridges without requiring large amounts of new material. While this practice was mainly used in the late 19th and 20th Centuries, many railroads continue to reuse spans were feasible. Deck plate girder spans were commonly used by railroads, as they were durable and easy to construct. Since the initial construction, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in good condition, with no deterioration noted. The author has ranked this bridge as being moderately significant, due to the magnitude of the structure.