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January 10, 1955: Death of Claude Allen Porter, architect of Duluth’s Aerial Bridge

On this day in 1955, Claude Allen Porter Turner, the engineer who designed Duluth’s Aerial Transfer Bridge, died at the age of 86 in Columbus, Ohio. Porter was working for the American Bridge Company in Minneapolis in 1899 when Duluth city engineer Thomas McGilvrary approached him with an idea: could the Duluth ship canal be traversed with an aerial transfer or “ferry” bridge similar to the one Ferdinand Arnodin built over the River Seine at Rouen, France? Sure, Porter said, with some alterations. Porter made several changes to the design for the French bridge, such as replacing the cables that held the bridge’s gondola car with stiff girders and adapting the propulsion system to eliminate a chain that ran under water the entire length of the bridge. Porter’s design—for the first stiff-girded aerial transfer bridge in the world—was built and operating over the Duluth ship canal by April, 1905. In 1928, as the city prepared to replace the transfer bridge with a lift bridge, Porter came to Duluth and inserted himself in the debate, convincing two of five city commissioners to champion his design. His efforts failed, and a much more elegant design was chosen. During his career Porter received over thirty patents for using reinforced concrete, including “mushroom cap” columns. His other notable designs include the Mendota Bridge between Fort Snelling and Mendota Minnesota—once the longest continuous concrete-arch bridge on the planet—and the 2,730-foot Arcola High Bridge north of Stillwater on the St. Croix River. Read much, much more about Duluth’s famous Aerial Bridge here.

C. A. P. Turner. (Image: Duluth Public Library)