Kelio istorija. Tiltų statybos raida

Abstract

In about TWO B. C. the Chinese built the world's first major bridge, the ju Qiao bridge at Quzhou. The first major pier and beam bridge outside of China was probably the bridge, built over the Euphrates in Babylon in about 605 B. C. The bridge was 10 m wide with an overall length of close to 900 m. The piers were built of stone. And remnants of seven still exist. An alternative approach to using piers was employed in a pontoon bridge in which the beams are supported on anchored boats. This method was first used in China over the Wei he river in 1200 B. C. and in Babylon around 800 B. C. The common structural alternatives to beam action were the rope, which works in tension, and the arch, which works in compression. Vines, rattan, oxhide, cane, and bamboo provided the first ropes with the tensile potential to span much larger distances than the existing natural beams. The first recorded bamboo suspension bridge was built in 285 B. C. by the prince of Qin in Sichuan. Iron chains were first used in Europe in 1237 to suspend galleries used as roads from the clift face and for segments of the bridge. Natural arch bridges are formed when relatively soft material erodes, leaving in place a rocky span. The first manufactured arches were created when inventive communities extended the steppingstone by carefully stacking a larger horizontal stone on top oi a smaller one. The first recorded keystone arch bridge u as the Pons Solares, which was built by the Romans across the Trevarone river in Italy in the seventh century B. C. The Romans soon made the semicircular keystone arch a major bridgebuilding form, although their technique was massive rather than adventurous. In difficult foundation conditions the Romans used both piles and cofferdams to provide the necessary sound foundation for the arch.