- Pile bridge
A pile bridge is a structure that uses foundations consisting of long poles (referred to as piles), which are made of
wood ,concrete orsteel and which are hammered into the soft soils beneath the bridge until the end of the pile reaches a hard layer of compacted soil or rock. Piles in such cases are hammered to a depth where the grip or friction of the pile and the soil surrounding it will support the load of the bridge deck. Bridging solely using the pile method is nowadays a rare occurrence.Roman pile bridges
Pile bridges have been used to cross rivers and other geological chasms since at least the time of the
Roman Empire . One such bridge was probablyPons Sublicius thought to have been first created around 642BC, although being made of wood; this bridge and none of the other Roman bridges of the period have survived the erosion of time.cite book | author=Glick, Thomas F. Livesey, Steven John & Wallis, Faith | title=Medieval Science, Technology, and Medicine: An Encyclopedia | publisher=Routledge | year=2005| id=ISBN 0415969301]Construction during medieval times
During the English
Middle Ages bridge building was a booming activity. Groups of piles, usually made ofelm oroak were driven together into the soil. The pile hammer was a construction that allowed a heavy weight to fall on the top of the pile. Each pile wore a "pile shoe" tip made of iron. A group so hammered was called a "straddle" and atop as well as surrounding the straddle was a pile supported platform called a "starling" which was filled withrubble before thepier and bridgedeck were added.Duration of pile bridges
Perhaps one of the most well-known of the medieval pile bridges, and one that was probably similarly constructed as a pile bridge by the Romans, are the older versions of
London Bridge . However even when the first version of the bridge as a stone structure, was commenced during the reign of Henry II in1176 , oak piles were used as part of the construction. Indeed some of those piles whilst driven in 1176 were still sturdy enough to be drawn in 1921, almost 750 years later.cite web | url = http://www.powerhousemuseum.com/collection/database/?irn=226292| title = D9291 Section of Oak Pile, London Bridge, driven 1176, drawn 1921. | publisher = Powerhouse Museum Sydney | accessdate = 2007-05-05 ]References and notes
ee also
*
Pons Sublicius
*London Bridge
*Deep foundation
*Kabouter
*Kvarnbron
*Dolphin (structure)
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