12th Street Viaduct: Kansas City, MO
For much of Kansas City’s history, its topography imposed restrictions on the flow of traffic across the confluence of the Kansas and Missouri Rivers. Pleistocene glaciation and the shifting course of the rivers created terraces of immovable bluffs and sheer bedrock cliffs. The depressions between the rivers is muddy and prone to flooding, posing an additional challenge for westward movement across this strategic location. The Kansas River is shallow and difficult to navigate with riverboats, while the Missouri River reaches widths approaching 1,000 feet, forestalling the construction of bridges until after the Civil War. Kansas City’s first railroad station and earliest industrial areas lay in this floodplain to the west of downtown, accessible by a handful of passes with a more shallow grade.
In 1887 an iron streetcar bridge was built off 12th street to provide easier access to the West Bottoms for workers living at the top of the bluff. Within a couple of decades that structure had become inadequate to support traffic into the West Bottoms, let alone across the Kansas River. In 1913 the City contracted local engineering firm Waddell and Harrington to build a replacement viaduct that could accommodate both a streetcar and the anticipated growth in automobile traffic.
The firm’s design was unbelievable in scope, attracting debate from engineers as to whether it could even be achieved. The double decker structure is over 2,000 feet long, sixty feet wide, and built of reinforced concrete, a construction method that was still relatively unfamiliar in the state. A crew of 200 men, mostly carpenters, erected the Twelfth Street Viaduct in under one year and significantly below budget. The completed structure was praised for its beauty and simplicity, which stands on classical forms like the Roman arch and rectangular columns.
Though the structure required significant maintenance work in 1963 and 2006, it still carries regular traffic, and the lower deck can be rented for events.