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Sydney Harbour Bridge - probably the most well known of suspended deck compression arch bridges A bridge is a structure built to span a gorge, valley, road, railroad track, river or other body of water, or any other physical obstacle.
The purpose of a bridge is to allow passage of people, vehicles, trains or ships over an obstacle.
A moveable bridge gives space for tall items such as ship's masts to pass through, or may be used to span distances that are variable in height or distance.
The first bridges were simple wooden logs or planks spanning a stream or such; the next examples found use stone, but again as a simple support and crossbeam arrangement. The arch was first used by the Roman Empire for bridges, and many Roman bridges and aqueducts still exist today. The Romans also had cement, which reduced the variation of strength found in natural stone. Brick and mortar bridges were built after the Roman era, as the technology for cement was lost.
During the 18th century, many innovations in the design of timber bridges by Hans Ulrich and Johannes GrubenmannSeveral members of the Swiss family Grubenmann were famous as joiners and civil engineers in the eighteenth century. The sons were innovators in bridge construction. Ulrich Grubenmann ( 1668 June 27, 1736) lived all his life in Gstalden, Appenzell Ausserr and others.
With the advent of the Industrial RevolutionThe Industrial Revolution is the name given to the massive social, economic, and technological change in 18th century and 19th century Great Britain. It commenced with the introduction of steam power (fuelled primarily by coal) and powered, automated mach of the 19th centuryAlternative meaning: Nineteenth Century (periodical ( 18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801- 1900. Events The Little Ice Age ended, trussIn medicine, a truss is a kind of surgical appliance, particularly one used for hernia patients. See truss (medicine) bridge for a single track railway, converted to pedestrian use and pipeline support. Outer vertical members are in tension, lower horizon systems of wrought ironWrought iron is a very pure form of commercial iron, having a very small carbon content. It is tough, malleable, ductile and can be easily welded. However, it is too soft to make blades from; steel, with a carbon content between wrought and the high-carbo were developed for larger bridges, but ironThis article is about metallic iron. For the ironing device, see ironing manganese iron cobalt Fe Ru Full table General Name, Symbol, Number iron, Fe, 26 Chemical series transition metal Group, Period, Block 8 (VIIIB), 4 , d Density, Hardness 7874 kg/m3, did not have the tensile strength to support large loadIn physics, a net force acting on a body causes that body to accelerate; that is, to change its velocity. The concept appeared first in the second law of motion of classical mechanics. It is usually expressed by the equation F m · a where F is the force,s. With the advent of steel, with its high tensile strength, much larger bridges were built, many using the ideas of Gustave Eiffel , which were first shown at the Eiffel Tower in Paris France.
| 250px Clifton Suspension Bridge spanning the River Avon in Bristol, England |
| Moon Bridge at the Summer Palace of the Empress Dowager Cixi, Beijing |