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A deep foundation is a type of
foundation Foundation may refer to: * Foundation (nonprofit), a type of charitable organization ** Foundation (United States law), a type of charitable organization in the U.S. ** Private foundation, a charitable organization that, while serving a good cause ...
that transfers building loads to the earth farther down from the surface than a
shallow foundation A shallow foundation is a type of building foundation that transfers structural load to the earth very near to the surface, rather than to a subsurface layer or a range of depths, as does a deep foundation. Customarily, a shallow foundation is cons ...
does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the
building site Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and co ...
. There are many reasons that a
geotechnical engineer Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It a ...
would recommend a deep foundation over a shallow foundation, such as for a
skyscraper A skyscraper is a tall continuously habitable building having multiple floors. Modern sources currently define skyscrapers as being at least or in height, though there is no universally accepted definition. Skyscrapers are very tall high-ris ...
. Some of the common reasons are very large design loads, a poor
soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...
at shallow depth, or site constraints like
property line A unit of real estate or immovable property is limited by a legal boundary (sometimes also referred to as a property line or a lot line). The boundary (in Latin: ''limes'') may appear as a discontinuation in the terrain: a ditch, a bank, a hedge, a ...
s. There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a
column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...
), drilled shafts, and caissons. Piles are generally driven into the ground
in situ ''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...
; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of
timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, wi ...
,
steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant t ...
,
reinforced concrete Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having hig ...
or
prestressed concrete Prestressed concrete is a form of concrete used in construction. It is substantially "prestressed" ( compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. Post-tensioned concreted ...
.


Driven foundations

Prefabricated Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is u ...
piles are driven into the ground using a pile driver. Driven piles are constructed of wood, reinforced concrete, or steel. Wooden piles are made from the trunks of tall trees. Concrete piles are available in square, octagonal, and round cross-sections (like Franki piles). They are reinforced with
rebar Rebar (short for reinforcing bar), known when massed as reinforcing steel or reinforcement steel, is a steel bar used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension. ...
and are often prestressed. Steel piles are either pipe piles or some sort of beam section (like an H-pile). Historically, wood piles used splices to join multiple segments end-to-end when the driven depth required was too long for a single pile; today, splicing is common with steel piles, though concrete piles can be spliced with mechanical and other means. Driving piles, as opposed to drilling shafts, is advantageous because the soil displaced by driving the piles compresses the surrounding soil, causing greater friction against the sides of the piles, thus increasing their load-bearing capacity. Driven piles are also considered to be "tested" for weight-bearing ability because of their method of installation; thus the motto of the Pile Driving Contractors' Association is "A Driven Pile...Is a Tested Pile!".


Pile foundation systems

Foundations relying on driven piles often have groups of piles connected by a
pile cap A pile cap is a thick concrete mat that rests on concrete or timber piles that have been driven into soft or unstable ground to provide a suitable stable foundation. It usually forms part of the deep foundation of a building, typically a multi-s ...
(a large concrete block into which the heads of the piles are embedded) to distribute loads that are greater than one pile can bear. Pile caps and isolated piles are typically connected with
grade beam A grade beam or grade beam footing is a component of a building's foundation. It consists of a reinforced concrete beam that transmits the load from a bearing wall into spaced foundations such as pile caps or caissons. It is used in conditions wher ...
s to tie the foundation elements together; lighter structural elements bear on the grade beams, while heavier elements bear directly on the pile cap.


Monopile foundation

A monopile foundation utilizes a single, generally large-diameter, foundation structural element to support all the loads (weight, wind, etc.) of a large above-surface structure. A large number of monopile foundationsOffshore Wind Turbine Foundations
2009-09-09, accessed 2010-04-12.
have been utilized in recent years for economically constructing fixed-bottom
offshore wind farm Offshore wind power or offshore wind energy is the generation of electricity through wind farms in bodies of water, usually at sea. There are higher wind speeds offshore than on land, so offshore farms generate more electricity per amount of c ...
s in shallow-water
subsea Subsea technology involves fully submerged ocean equipment, operations, or applications, especially when some distance offshore, in deep ocean waters, or on the seabed. The term ''subsea'' is frequently used in connection with oceanography, marin ...
locations.Constructing a turbine foundation
Horns Rev project, Elsam monopile foundation construction process, accessed 2010-04-12]
For example, the
Horns Rev Horns Rev is a shallow sandy reef of glacial deposits in the eastern North Sea, about off the westernmost point of Denmark, Blåvands Huk.
wind farm A wind farm or wind park, also called a wind power station or wind power plant, is a group of wind turbines in the same location used to produce electricity. Wind farms vary in size from a small number of turbines to several hundred wind turb ...
in the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegia ...
west of
Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , established ...
utilizes 80 large monopiles of 4 metres diameter sunk 25 meters deep into the seabed,Horns Revolution
, Modern Power Systems, 2002-10-05, accessed 2010-04-14.
while the Lynn and Inner Dowsing Wind Farm off the coast of England went online in 2008 with over 100 turbines, each mounted on a 4.7-metre-diameter monopile foundation in ocean depths up to 18 metres. The typical construction process for a wind turbine subsea monopile foundation in sand includes driving a large hollow steel pile, of some 4 m in diameter with approximately 50mm thick walls, some 25 m deep into the seabed, through a 0.5 m layer of larger stone and gravel to minimize erosion around the pile. A transition piece (complete with pre-installed features such as boat-landing arrangement,
cathodic protection Cathodic protection (CP; ) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded " sacrifi ...
, cable ducts for sub-marine cables, turbine tower flange, etc.) is attached to the driven pile, and the sand and water are removed from the centre of the pile and replaced with concrete. An additional layer of even larger stone, up to 0.5 m diameter, is applied to the surface of the seabed for longer-term erosion protection.


Drilled piles

Also called caissons, drilled shafts, drilled piers, cast-in-drilled-hole piles (CIDH piles) or cast-in-situ piles, a
borehole A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petro ...
is drilled into the ground, then concrete (and often some sort of reinforcing) is placed into the borehole to form the pile. Rotary boring techniques allow larger diameter piles than any other piling method and permit pile construction through particularly dense or hard strata. Construction methods depend on the geology of the site; in particular, whether boring is to be undertaken in 'dry' ground conditions or through water-saturated strata. Casing is often used when the sides of the borehole are likely to slough off before concrete is poured. For end-bearing piles, drilling continues until the borehole has extended a sufficient depth (socketing) into a sufficiently strong layer. Depending on site geology, this can be a
rock layer In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...
, or hardpan, or other dense, strong layers. Both the diameter of the pile and the depth of the pile are highly specific to the ground conditions, loading conditions, and nature of the project. Pile depths may vary substantially across a project if the bearing layer is not level. Drilled piles can be tested using a variety of methods to verify the pile integrity during installation.


Under-reamed piles

Under-reamed piles have mechanically formed enlarged bases that are as much as 6 m in diameter. The form is that of an inverted cone and can only be formed in stable soils. The larger base diameter allows greater bearing capacity than a straight-shaft pile. These piles are suited for expansive soils which are often subjected to seasonal moisture variations, or for loose or soft strata. They are used in normal ground condition also where economics are favorable. Under reamed piles foundation is used for the following soils:- 1. Under reamed piles are used in black cotton soil: This type of soil expands when it comes in contact with water and contraction occurs when water is removed. So that cracks appear in the construction done on such clay. An under reamed pile is used in the base to remove this defect. 2. Under reamed piles are used in low bearing capacity Outdated soil (filled soil) 3.Under reamed piles are used in sandy soil when water table is high. 4. Under reamed piles are used, Where lifting forces appear at the base of foundation.


Augercast pile

An augercast pile, often known as a continuous flight augering (CFA) pile, is formed by drilling into the ground with a hollow stemmed continuous flight auger to the required depth or degree of resistance. No casing is required. A cement
grout Grout is a dense fluid which hardens to fill gaps or used as reinforcement in existing structures. Grout is generally a mixture of water, cement and sand, and is employed in pressure grouting, embedding rebar in masonry walls, connecting sect ...
mix is then pumped down the stem of the auger. While the cement grout is pumped, the auger is slowly withdrawn, conveying the soil upward along the flights. A shaft of fluid cement grout is formed to ground level. Reinforcement can be installed. Recent innovations in addition to stringent quality control allows reinforcing cages to be placed up to the full length of a pile when required. Augercast piles cause minimal disturbance and are often used for noise-sensitive and environmentally-sensitive sites. Augercast piles are not generally suited for use in contaminated soils, because of expensive waste disposal costs. In cases such as these, a displacement pile (like Olivier piles) may provide the cost efficiency of an augercast pile and minimal environmental impact. In ground containing obstructions or cobbles and boulders, augercast piles are less suitable as refusal above the design pile tip elevation may be encountered.


Pier and grade beam foundation

In drilled pier foundations, the piers can be connected with
grade beam A grade beam or grade beam footing is a component of a building's foundation. It consists of a reinforced concrete beam that transmits the load from a bearing wall into spaced foundations such as pile caps or caissons. It is used in conditions wher ...
s on which the structure sits, sometimes with heavy column loads bearing directly on the piers. In some residential construction, the piers are extended above the ground level, and wood beams bearing on the piers are used to support the structure. This type of foundation results in a crawl space underneath the building in which wiring and duct work can be laid during construction or re-modelling.


Speciality piles


Jet-piles

In jet piling high pressure water is used to set piles. High pressure water cuts through soil with a high-pressure jet flow and allows the pile to be fitted. One advantage of Jet Piling: the water jet lubricates the pile and softens the ground. The method is in use in Norway.


Micropiles

Micropiles are small diameter, generally less than 300mm diameter, elements that are drilled and grouted in place.  They typically get their capacity from skin friction along the sides of the element, but can be end bearing in hard rock as well. Micropiles are usually heavily reinforced with steel comprising more than 40% of their cross section. They can be used as direct structural support or as ground reinforcement elements.  Due to their relatively high cost and the type of equipment used to install these elements, they are often used where access restrictions and or very difficult ground conditions (cobbles and boulders, construction debris, karst, environmental sensitivity) exists or to retrofit existing structures.  Occasionally, in difficult ground, they are used for new construction foundation elements. Typical applications include
underpinning In construction or renovation, underpinning is the process of strengthening the foundation of an existing building or other structure. Underpinning may be necessary for a variety of reasons: * The original foundation isn't strong or stable enough. ...
, bridge,
transmission tower A transmission tower, also known as an electricity pylon or simply a pylon in British English and as a hydro tower in Canadian English, is a tall structure, usually a steel lattice tower, used to support an overhead power line. In electrical gri ...
and slope stabilization projects.


Tripod piles

The use of a tripod rig to install piles is one of the more traditional ways of forming piles. Although unit costs are generally higher than with most other forms of piling, it has several advantages which have ensured its continued use through to the present day. The tripod system is easy and inexpensive to bring to site, making it ideal for jobs with a small number of piles.


Sheet piles

Sheet piling is a form of driven piling using thin interlocking sheets of steel to obtain a continuous barrier in the ground. The main application of sheet piles is in
retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...
s and
cofferdams A cofferdam is an enclosure built within a body of water to allow the enclosed area to be pumped out. This pumping creates a dry working environment so that the work can be carried out safely. Cofferdams are commonly used for construction or re ...
erected to enable permanent works to proceed. Normally, vibrating hammer, t-crane and crawle drilling are used to establish sheet piles.


Soldier piles

Soldier piles, also known as king piles or Berlin walls, are constructed of wide flange steel H sections spaced about 2 to 3 m apart and are driven prior to excavation. As the excavation proceeds, horizontal timber sheeting (lagging) is inserted behind the H pile flanges. The horizontal earth pressures are concentrated on the soldier piles because of their relative rigidity compared to the lagging. Soil movement and
subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope move ...
is minimized by maintaining the lagging in firm contact with the soil. Soldier piles are most suitable in conditions where well constructed walls will not result in subsidence such as over-consolidated clays, soils above the water table if they have some cohesion, and free draining soils which can be effectively dewatered, like sands. Unsuitable soils include soft clays and weak running soils that allow large movements such as loose sands. It is also not possible to extend the wall beyond the bottom of the excavation, and dewatering is often required.


Screw piles

Screw piles, also called ''helical piers'' and ''screw foundations'', have been used as foundations since the mid 19th century in
screw-pile lighthouse A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Constructio ...
s. Screw piles are galvanized iron pipe with helical fins that are turned into the ground by machines to the required depth. The screw distributes the load to the soil and is sized accordingly.


Suction piles

Suction piles are used underwater to secure floating platforms. Tubular piles are driven into the seabed (or more commonly dropped a few metres into a soft seabed) and then a pump sucks water out at the top of the tubular, pulling the pile further down. The proportions of the pile (diameter to height) are dependent upon the soil type. Sand is difficult to penetrate but provides good holding capacity, so the height may be as short as half the diameter. Clays and muds are easy to penetrate but provide poor holding capacity, so the height may be as much as eight times the diameter. The open nature of gravel means that water would flow through the ground during installation, causing 'piping' flow (where water boils up through weaker paths through the soil). Therefore, suction piles cannot be used in gravel seabeds.


Adfreeze piles

In high latitudes where the ground is continuously frozen, adfreeze piles are used as the primary structural foundation method. Adfreeze piles derive their strength from the bond of the frozen ground around them to the surface of the pile. Adfreeze pile foundations are particularly sensitive in conditions which cause the permafrost to melt. If a building is constructed improperly then it can melt the ground below, resulting in a failure of the foundation system.


Vibrated stone columns

Vibrated stone columns are a ground improvement technique where columns of coarse aggregate are placed in soils with poor
drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging (anaerobic condition ...
or bearing capacity to improve the soils.


Hospital piles

Specific to marine structures, hospital piles (also known as gallow piles) are built to provide temporary support to marine structure components during refurbishment works. For example, when removing a river pontoon, the brow will be attached to hospital pile to support it. They are normal piles, usually with a chain or hook attachment.


Piled walls

These methods of
retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...
construction employ bored piling techniques, normally CFA or rotary. They provide special advantages where available working space dictates that basement excavation faces be vertical. Both methods offer technically effective and offer a cost efficient temporary or permanent means of retaining the sides of bulk excavations even in water bearing strata. When used in permanent works, these walls can be designed to accommodate vertical loads in addition to moments and horizontal
force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...
s. Construction of both methods is the same as for foundation bearing piles. Contiguous walls are constructed with small gaps between adjacent piles. The size of this space is determined by the strength of the soils.


Secant piled walls

Secant pile walls are constructed such that space is left between alternate 'female' piles for the subsequent construction of 'male' piles. Construction of 'male' piles involves boring through the concrete in the 'female' piles hole in order to key 'male' piles between. The male pile is the one where steel reinforcement cages are installed, though in some cases the female piles are also reinforced. Secant piled walls can either be true hard/hard, hard/intermediate (firm), or hard/soft, depending on design requirements. Hard refers to structural concrete and firm or soft is usually a weaker grout mix containing bentonite. All types of wall can be constructed as free standing
cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...
s, or may be propped if space and sub-structure design permit. Where party wall agreements allow, ground anchors can be used as tie backs.


Slurry walls

A slurry wall is a barrier built under ground using a mix of
bentonite Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-mon ...
and water to prevent the flow of groundwater. A trench that would collapse due to the
hydraulic pressure Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...
in the surrounding soil does not collapse as the slurry balances the hydraulic pressure.


Deep mixing/mass stabilization techniques

These are essentially variations of ''
in situ ''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...
'' reinforcements in the form of piles (as mentioned above), blocks or larger volumes. Cement, lime/quick lime, flyash, sludge and/or other binders (sometimes called stabilizer) are mixed into the soil to increase bearing capacity. The result is not as solid as concrete, but should be seen as an improvement of the bearing capacity of the original soil. The technique is most often applied on
clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay parti ...
s or organic
soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...
s like
peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficient ...
. The mixing can be carried out by pumping the binder into the soil whilst mixing it with a device normally mounted on an excavator or by excavating the masses, mixing them separately with the binders and refilling them in the desired area. The technique can also be used on lightly contaminated masses as a means of binding contaminants, as opposed to excavating them and transporting to landfill or processing.


Materials


Timber

As the name implies,
timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, wi ...
piles are made of
wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
. Historically, timber has been a plentiful, locally available resource in many areas. Today, timber piles are still more affordable than concrete or steel. Compared to other types of piles (steel or concrete), and depending on the source/type of timber, timber piles may not be suitable for heavier loads. A main consideration regarding timber piles is that they should be protected from rotting above groundwater level. Timber will last for a long time below the groundwater level. For timber to rot, two elements are needed: water and oxygen. Below the groundwater level, dissolved oxygen is lacking even though there is ample water. Hence, timber tends to last for a long time below the groundwater level. In 1648, the
Royal Palace of Amsterdam The Royal Palace of Amsterdam in Amsterdam (Dutch: ''Koninklijk Paleis van Amsterdam'' or ) is one of three palaces in the Netherlands which are at the disposal of the monarch by Act of Parliament. It is situated on the west side of Dam Square i ...
was constructed on 13,659 timber piles that still survive today since they were below groundwater level. Timber that is to be used above the water table can be protected from decay and insects by numerous forms of
wood preservation Wood easily degrades without sufficient preservation. Apart from structural wood preservation measures, there are a number of different chemical preservatives and processes (also known as "timber treatment", "lumber treatment" or "pressure treat ...
using pressure treatment (
alkaline copper quaternary Alkaline copper quaternary, usually abbreviated ACQ, is a type of water-based wood preservative product containing a soluble copper(II) complex and quaternary ammonium alkyl- or aryl-substituted compounds ("quats"). Thus the product was originall ...
(ACQ),
chromated copper arsenate Chromated copper arsenate (CCA) is a wood preservative containing compounds of chromium, copper, and arsenic, in various proportions. It is used to impregnate timber and other wood products, especially those intended for outdoor use, in order to p ...
(CCA),
creosote Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood or fossil fuel. They are typically used as preservatives or antiseptics. Some creosote types were ...
, etc.). Splicing timber piles is still quite common and is the easiest of all the piling materials to splice. The normal method for splicing is by driving the leader pile first, driving a steel tube (normally 60–100 cm long, with an internal diameter no smaller than the minimum toe diameter) half its length onto the end of the leader pile. The follower pile is then simply slotted into the other end of the tube and driving continues. The steel tube is simply there to ensure that the two pieces follow each other during driving. If uplift capacity is required, the splice can incorporate bolts, coach screws, spikes or the like to give it the necessary capacity.


Iron

Iron may be used for piling. These may be
ductile Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stres ...
.


Steel

Pipe Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circular ...
piles are a type of steel driven pile foundation and are a good candidate for inclined ( battered) piles. Pipe piles can be driven either open end or closed end. When driven open end, soil is allowed to enter the bottom of the pipe or tube. If an empty pipe is required, a jet of water or an auger can be used to remove the soil inside following driving. Closed end pipe piles are constructed by covering the bottom of the pile with a steel plate or cast steel shoe. In some cases, pipe piles are filled with concrete to provide additional moment capacity or corrosion resistance. In the United Kingdom, this is generally not done in order to reduce the cost. In these cases corrosion protection is provided by allowing for a sacrificial thickness of steel or by adopting a higher grade of steel. If a concrete filled pipe pile is corroded, most of the load carrying capacity of the pile will remain intact due to the concrete, while it will be lost in an empty pipe pile. The structural capacity of pipe piles is primarily calculated based on steel strength and concrete strength (if filled). An allowance is made for corrosion depending on the site conditions and local building codes. Steel pipe piles can either be new steel manufactured specifically for the piling industry or reclaimed steel tubular casing previously used for other purposes such as oil and gas exploration. H-Piles are structural beams that are driven in the ground for deep foundation application. They can be easily cut off or joined by welding or mechanical drive-fit splicers. If the pile is driven into a soil with low pH value, then there is a risk of corrosion, coal-tar epoxy or cathodic protection can be applied to slow or eliminate the corrosion process. It is common to allow for an amount of corrosion in design by simply over dimensioning the cross-sectional area of the steel pile. In this way, the corrosion process can be prolonged up to 50 years.


Prestressed concrete piles

Concrete piles are typically made with steel reinforcing and prestressing tendons to obtain the tensile strength required, to survive handling and driving, and to provide sufficient bending resistance. Long piles can be difficult to handle and transport. Pile joints can be used to join two or more short piles to form one long pile. Pile joints can be used with both precast and prestressed concrete piles.


Composite piles

A "composite pile" is a pile made of steel and concrete members that are fastened together, end to end, to form a single pile. It is a combination of different materials or different shaped materials such as pipe and H-beams or steel and concrete.


Construction machinery for driving piles into the ground

Construction machinery used to drive piles into the ground: * Pile driver is a device for placing piles in their designed position. * Diesel hammer is a device for hammering piles into the ground. * Hydraulic hammer is removable working equipment of hydraulic excavators, hydroficated machines (stationary rock breakers, loaders, manipulators, pile driving hammers) used for processing strong materials (rock, soil, metal) or pile driving elements by impact of falling parts dispersed by high-pressure fluid. * Vibratory pile driver is a machine for driving piles into sandy and clay soils. * Press-in pile driver is a machine for sinking piles into the ground by means of static force transmission. * Universal drilling machine.


See also

* Eurocode EN 1997 * International Society for Micropiles *
Post in ground A post in ground construction, also called earthfast or hole-set posts, is a type of construction in which vertical, roof-bearing timbers, called posts, are in direct contact with the ground. They may be placed into excavated postholes, driven ...
construction also called earthfast or
posthole In archaeology a posthole or post-hole is a cut feature used to hold a surface timber or stone. They are usually much deeper than they are wide; however, truncation may not make this apparent. Although the remains of the timber may survive, most ...
construction; a historic method of building wooden structures. *
Stilt house Stilt houses (also called pile dwellings or lake dwellings) are houses raised on stilts (or piles) over the surface of the soil or a body of water. Stilt houses are built primarily as a protection against flooding; they also keep out vermin. The ...
, also known as a lake house; an ancient, historic house type built on pilings. * Shallow foundations * Pile bridge * Larssen sheet piling


Notes


References


Italiantrivelle Foundation Industry
The Deep Foundation web portal Italiantrivelle is the number one source of information regarding the Foundation Industry. (Link needs to be removed or updated, links to inappropriate content) * ''Fleming, W. G. K. et al., 1985, Piling Engineering, Surrey University Press; Hunt, R. E., Geotechnical Engineering Analysis and Evaluation, 1986, McGraw-Hill.'' * Coduto, Donald P. ''Foundation Design: Principles and Practices'' 2nd ed., Prentice-Hall Inc., 2001.
NAVFAC DM 7.02 Foundations and Earth Structures
U.S. Naval Facilities Engineering Command, 1986. * Rajapakse, Ruwan., ''Pile Design and Construction Guide'', 2003 * Tomlinson, P.J., ''Pile Design and Construction Practice'', 1984
Stabilization of Organic Soils

Sheet piling handbook
2010


External links


Deep Foundations Institute
{{DEFAULTSORT:Deep Foundation Articles containing video clips