Background
Although British engineers suggested using the cantilever form as a replacement for non-statically determinate trusses as early as 1846, the first modern cantilever actually built was Heinrich Gerber's Hassfurt Bridge over the Main River in Germany (1867), with a central span of 38 m.
The next important cantilever was built by American engineer C. Shaler Smith, ten years later in 1877. It provided the first practical test of the application of the cantilever principle to long-span bridge design. He built what was then the world's longest cantilever for the Cincinnati Southern Railway over a 366 m wide and 84 m deep gorge of the Kentucky River near Dixville, Kentucky.
Other important counterbalanced spans are the Michigan Central Railroad bridge over the Niagara Gorge (this bridge), designed by Charles Conrad Schneider/Apolda in 1883. With cantilever arms supporting a simple suspended truss, this 151 m span and, the nearly identical Fraser River Bridge in British Columbia, Canada, directed the attention of the engineering world to this new bridge form. These two were the prototypes for subsequent cantilevers, the Poughkeepsie Bridge over the Hudson River in New York, Young's High Bridge over the Kentucky River, the Forth Rail Bridge in Scotland, and the Quebec Bridge in Canada.
Read more about this topic: Niagara Cantilever Bridge
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