"uniontown" - 1 õppematerjal

Bridges presentation

Suspension bridges Although suspension bridges had been known in China as early as 206 BC, the first chain suspension bridge did not appear in Europe until 1741, when the 70ft (21m) span Winch Bridge was constructed over a chasm of the River Tees (UK), with the flooring laid directly on two chains. It was an American, James Finley, however, who built the first practical suspension bridge in 1796 in the USA. This was a bridge over Jacobs Creek near Uniontown, Pennsylvania, which Finley described as a "stiffened" bridge in an article he published in Portfolio in 1810. The span displayed all the essential elements of the modern suspension bridge: a level deck hung from a catenary system suspended over towers and anchored in the ground, and a truss-stiffened deck, resulting in a rigid bridge capable of supporting relatively heavy loads. The world's first wire-cable suspension bridge was a 408ft (124m) temporary footbridge built in