A pile bridge is a structure that uses foundations

Foundation (architecture)

A foundation is the lowest and supporting layer of a structure. Foundations are generally divided into two categories: shallow foundations and deep foundations.-Shallow foundations:...

 consisting of long poles (referred to as piles), which are made of wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 or steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 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

Roman Empire

The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

. One such bridge was probably Pons Sublicius

Pons Sublicius

The earliest known bridge of ancient Rome, Italy, the Pons Sublicius, spanned the Tiber River near the Forum Boarium downstream from the Tiber Island, near the foot of the Aventine Hill. According to tradition, its construction was ordered by Ancus Martius around 642 BC, but this date is...

 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.

Construction during medieval times

During the English

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 Middle Ages

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

 bridge building was a booming activity. Groups of piles, usually made of elm

Elm

Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...

 or oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 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

Starling (architecture)

In architecture, a starling or, more commonly, cutwater is a defensive bulwark, usually built with pilings or bricks, surrounding the supports of a bridge or similar construction...

" which was filled with rubble

Rubble

Rubble is broken stone, of irregular size, shape and texture. This word is closely connected in derivation with "rubbish", which was formerly also applied to what we now call "rubble". Rubble naturally found in the soil is known also as brash...

 before the pier

Pier

A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...

 and bridge deck

Deck (bridge)

A bridge deck or road bed is the roadway, or the pedestrian walkway, surface of a bridge. It is not to be confused with any deck of a ship.The deck may be of concrete,wood which in turn may be covered with asphalt concrete or other pavement...

 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

London Bridge

London Bridge is a bridge over the River Thames, connecting the City of London and Southwark, in central London. Situated between Cannon Street Railway Bridge and Tower Bridge, it forms the western end of the Pool of London...

. However even when the first version of the bridge as a stone structure, was commenced during the reign of Henry II

Henry II of England

Henry II ruled as King of England , Count of Anjou, Count of Maine, Duke of Normandy, Duke of Aquitaine, Duke of Gascony, Count of Nantes, Lord of Ireland and, at various times, controlled parts of Wales, Scotland and western France. Henry, the great-grandson of William the Conqueror, was the...

 in 1176, oak piles were used as part of the construction. Indeed some of those piles while driven in 1176 were still sturdy enough to be drawn in 1921, almost 750 years later.

See also

• Pons Sublicius
  Pons Sublicius
  The earliest known bridge of ancient Rome, Italy, the Pons Sublicius, spanned the Tiber River near the Forum Boarium downstream from the Tiber Island, near the foot of the Aventine Hill. According to tradition, its construction was ordered by Ancus Martius around 642 BC, but this date is...
  
  
• London Bridge
  London Bridge
  London Bridge is a bridge over the River Thames, connecting the City of London and Southwark, in central London. Situated between Cannon Street Railway Bridge and Tower Bridge, it forms the western end of the Pool of London...
  
  
• Deep foundation
  Deep foundation
  A deep foundation is a type of foundation distinguished from shallow foundations by the depth they are embedded into the ground. There are many reasons a geotechnical engineer would recommend a deep foundation over a shallow foundation, but some of the common reasons are very large design loads, a...
  
  
• Kabouter
  Kabouter
  Kabouter is the Dutch/Afrikaans word for gnome or leprechaun. In folklore, the Dutch Kabouters are akin to the Irish Leprechaun, Scandinavian Tomte, the English Hob or Brownie and the German Klabauter or kobold. The term kabouter was also adopted by a 1970s hippie movement in Amsterdam that sprang...
  
  
• Fredriksdalsbron
• Dolphin (structure)
  Dolphin (structure)
  A dolphin is a man-made marine structure that extends above the water level and is not connected to shore.Dolphins are usually installed to provide a fixed structure when it would be impractical to extend the shore to provide a dry access facility, for example, when ships are greater than the...