The Amelia Earhart Network Tied Arch Bridge Replacement Project

A replacement bridge for U.S. 59 across the Missouri River, from Atchison, Kansas to Winthrop, Missouri in the United States has been constructed. Interactions between the flow around this bridge and two existing bridges adjacent to the new bridge had the potential to create large scour holes. Since the original bridge would need to remain open during construction, a scour study was performed to determine the placement of the piers. The new bridge uses prestressed concrete bulb tee girder spans for the approaches and one 160.6 m (527 foot) steel network tied arch for the main navigation span. The bridge was designed in 2008 and was one of the first modern tied arch bridges that used internal redundancy for fracture critical members using bolted angles at the intersection of the tie girder webs and flanges in the United States. Due to vertical clearance constraints, the tied arch contains a framed-in-floor system to minimize structure depth. This also required a specific slab pouring sequence to relieve the elongation effects of the tie girder during construction. This signature structure opened to traffic in 2012 and project completion occurred in summer of 2013. This paper focuses on the pier placement relating to the scour concerns and the design of the tied arch span.