Cantilever Bridge

A cantilever bridge is a bridge built from cantilevers, horizontal structural projections supported at only one end, that can be formed from beams, steel trusses or prestressed concrete box girders and can span longer distances than a bridge resting on continuous supports. Simple cantilever bridges built from logs originated in Tibet, but the modern form emerged in nineteenth-century engineering once builders recognized that a continuous structure spanning multiple supports could distribute loads more efficiently; the German engineer Heinrich Gerber patented a hinged girder design in 1866, and his Hassfurt Bridge over the Main River in Germany, completed in 1867 with a central span of 124 feet, is recognized as the first modern cantilever bridge. The type matured quickly afterward, from the 1877 High Bridge of Kentucky and the 1883 Niagara Cantilever Bridge to Scotland's 1890 Forth Bridge, which held the record for the world's longest span for 29 years until Canada's Quebec Bridge surpassed it in 1919.