Historical Developments in Civil Structures
• The word Beam comes from the old English word for wood.
• Beams may be loosely grouped into two types; if the beam is supported at both ends it is a simply supported beam, whereas if it is only supported at one end it is a cantilevered beam.
• A beam may be wood, metal or stone.
• The Greek historian Herodotus wrote of a multi-span beam bridge in Babylon (present day Iraq) in the 5th Century BC.
• Early beam bridges often used timber, but because timber rots and is attacked by borers and termites there are few left.
• In 55 BC Julius Caesar built a 550m long wooden beam bridge that incorporated 50 spans; construction took ten days.
• By 1570, Italian architect, Andrea Palladio had developed a truss girder bridge.
• Early in the 19th Century, English engineer James Warren developed a truss girder bridge that would be extensively used by railway engineers.
• It was In America, however, that the truss girder was developed to its modern day form
• In 1847, Squire Whipple developed the iron truss, a design that carried on to the twentieth century
• In 1849, the famous English engineer, Robert Stephenson, developed the Bowstring Girder.
• In 1850 Stephenson collaborated with others to complete another important type of Beam Bridge.
• In 1867, Heinrich Gerber built the first balanced cantilever bridge over the River Main in Germany.
• In 1879 the Tay Bridge (on the same rail line as the forth Bridge) was built
• 1948 saw the development of one of the most commonly used beam bridges today, the box girder bridge.
Masonry Arch Bridges
• The stone arch bridge was used extensively by Roman engineers from 200 BC to 400 AD
• The oldest Roman bridge is the Ponte Rotto in Rome
• The biggest Roman bridge span was 42m on a 4 span viaduct in Narni, on the Via Flaminia....