10-04-2017, 08:25 PM
History of Bridges
The New River Gorge Bridge is the world's longest spanning, steel single-arch bridge. Soaring 876 feet above the rugged whitewaters of West Virginia's New River. It is also the second tallest bridge in the United States.
Clapper Bridge
This type of bridge is called a clapper bridge. It is one of the earliest bridge constructions. Such simple bridges are probably still built to day in many places. In general, though bridge construction has changed greatly.
Roman Arch Bridges
The ancient Romans refined bridge building with two important contributions.
Nearly all of their bridges used the arch design -- a structure that can support more weight than a flat surface can.
Also, the Romans discovery of natural cement allowed them to build strong, long-standing bridges.
Many of these ancient Roman bridges are still standing today
Chinese Bridges
There were excellent bridge buildings in Asia, too.
Some early bridges in Asia used a cantilever design. This design enabled the builder to make simple, long-span bridges across fairly wide rivers.
One famous bridge in China, built about 1300 years ago, is the Great Stone Bridge.
Renaissance Contributions
Leonardo Da Vinci and Galileo developed theories about the strength of building materials.
Their theories have helped architects understand how to make strong structures from lightweight materials.
First Metal Bridges
About 200 years ago, the first cast-iron bridge was built. This was the Iron Bridge at Coalbrookdale in England.
Before that time, bridges were made of stone, brick, clay, or timber.
Eventually, wrought iron was used instead of cast iron.
Much later, steel was used.