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A deep foundation is a type of foundation. Deep foundations are 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 poor soil at shallow depth, or site constraints (like property lines). There are different terms used to describe different types of deep foundations including piles, drilled shafts, caissons, and piers. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete and pre-tensioned concrete. Deep foundations can be installed by either driving them into the ground or drilling a shaft and filling it with concrete, mass or reinforced. Image File history File linksMetadata Download high-resolution version (600x800, 82 KB) Piledriving at the Maxwell Bridge (Imola Avenue) in Napa, California. ...
Image File history File linksMetadata Download high-resolution version (600x800, 82 KB) Piledriving at the Maxwell Bridge (Imola Avenue) in Napa, California. ...
Napa is the county seat of Napa County, California. ...
A foundation is a structure that transmits loads from a building or road to the underlying ground. ...
A shallow foundation is a type of foundation which transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths as does a deep foundation. ...
Bostons Big Dig presented geotechnical challenges in an urban environment. ...
Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Technically, soil forms the pedosphere: the interface between the lithosphere (rocky part of the planet) and the biosphere, atmosphere, and hydrosphere. ...
Timber in storage for later processing at a sawmill Timber is a term used to describe wood, either standing or that has been processed for use—from the time trees are felled, to its end product as a material suitable for industrial use—as structural material for construction or wood...
The steel cable of a colliery winding tower. ...
Reinforced concrete at Sainte Jeanne dArc Church (Nice, France): architect Jacques Dror, 1926–1933 Reinforced concrete, also called ferroconcrete in some countries, is concrete in which reinforcement bars (rebars) or fibers have been incorporated to strengthen a material that would otherwise be brittle. ...
Traditional reinforced concrete is based on the use of steel reinforcement bars, rebar, inside poured concrete. ...
Driven foundations
Pipe piles being driven into the ground. Prefabricated piles are driven into the ground using a pile driver. Driven piles are either wood, concrete, or steel. Wooden piles are made from trunks of tall trees. Concrete piles are available in square, octagonal, and round cross-sections. They are reinforced with rebar and are often prestressed. Steel piles are either pipe piles or some sort of beam section (like an H-pile). Historically, wood piles were spliced together when the design length was too large for a single pile; today, splicing is only common with steel piles, though concrete piles can be spliced with difficulty. 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. Image File history File links Size of this preview: 798 × 600 pixelsFull resolution (953 × 716 pixel, file size: 184 KB, MIME type: image/jpeg) Green piling Ltd File historyClick on a date/time to view the file as it appeared at that time. ...
Image File history File links Size of this preview: 798 × 600 pixelsFull resolution (953 × 716 pixel, file size: 184 KB, MIME type: image/jpeg) Green piling Ltd File historyClick on a date/time to view the file as it appeared at that time. ...
A pneumatic crane working as a pile driver. ...
A tied rebar beam cage. ...
Traditional reinforced concrete is based on the use of steel reinforcement bars, rebar, inside poured concrete. ...
Pile foundation systems Foundations relying on driven piles often have groups of piles connected by a pile cap (a large concrete block into which the heads of the piles are embedded) to distribute loads which are larger than one pile can bear. Pile caps and isolated piles are typically connected with grade beams to tie the foundation elements together; lighter structural elements bear on the grade beams while heavier elements bear directly on the pile cap.
Drilled piles Also called drilled piers or Cast-in-drilled-hole piles (CIDH piles). Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1200 × 1600 pixel, file size: 703 KB, MIME type: image/jpeg) Deep foundation machine in Amsterdam File historyClick on a date/time to view the file as it appeared at that time. ...
Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1200 × 1600 pixel, file size: 703 KB, MIME type: image/jpeg) Deep foundation machine in Amsterdam File historyClick on a date/time to view the file as it appeared at that time. ...
It has been suggested that Mokum be merged into this article or section. ...
Rotary boring techniques offer 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-logged but stable strata - i.e. 'wet boring'.
'Dry' boring methods employ the use of a temporary casing to seal the pile bore through water-bearing or unstable strata overlying suitable stable material. Upon reaching the design depth, a reinforcing cage is introduced, concrete is poured in the bore and brought up to the required level. The casing can be withdrawn or left in situ.
'Wet' boring also employs a temporary casing through unstable ground and is used when the pile bore cannot be sealed against water ingress. Boring is then undertaken using a digging bucket to drill through the underlying soils to design depth. The reinforcing cage is lowered into the bore and concrete is placed by tremmie pipe, following which, extraction of the temporary casing takes place.
In some cases there may be a need to employ drilling fluids (such as bentonite suspension) in order to maintain a stable shaft. Rotary auger piles are available in diameters from 350 mm to 2400 mm and using these techniques, pile lengths of beyond 50 metres can be achieved. Bentonite - USGS Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite, (Na,Ca)0. ...
Underreamed piles Underream piles have mechanically formed enlarged bases that have been as much as 6 m in diameter. The form is that of an inverted cone and can only be formed in stable soils. In such conditions they allow very high load bearing capacities.
Auger cast pile An auger cast pile, often known as a 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 high slump concrete mix is then pumped down the stem of the auger. While the concrete is pumped, the auger is slowly withdrawn, lifting the spoil on the flights. A shaft of fluid concrete is formed to ground level. Reinforcement placed by hand is normally limited to 6 metres in depth. Longer reinforcement cages can be installed by a vibrator, or placed prior to pouring concrete if appropriate specialized drilling equipment is used. Study of a man using an auger, for The Seven Sorrows of the Virgin, Albrecht Dürer, ca 1496 An auger is a device for moving material or liquid by means of a rotating helical flighting. ...
Casing is a metal tube used during drilling an oil well in combination with cement to sequentially stabilize recently drilled formation. ...
Concrete being poured, raked and vibrated into place in residential construction in Toronto, Ontario, Canada. ...
An electrically driven pump (electropump) for waterworks near the Hengsteysee, Germany. ...
A tied rebar beam cage. ...
Auger cast piles cause minimal disturbance, and are often used for noise and environmentally sensitive sites. Auger cast piles are not generally suited for use in contaminated soils, due to expensive waste disposal costs. In ground containing obstructions or cobbles and boulders, auger-cast piles are less suitable as damage can occur to the auger.
Pier and grade beam foundation In most drilled pier foundations, the piers are connected with grade beams - concrete beams at grade (also referred to as 'ground' beams) - and the structure is constructed to bear on the grade beams, 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 remodeling. A statically determinate beam, bending under an evenly distributed load. ...
Look up grade in Wiktionary, the free dictionary. ...
Electrical wiring in general refers to insulated conductors used to carry electricity, and associated devices. ...
Specialty piles ImageMetadata File history File links Download high resolution version (2400x1800, 711 KB) Minipiling File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
ImageMetadata File history File links Download high resolution version (2400x1800, 711 KB) Minipiling File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
Micropiles Micropiles, also called mini piles, are used for underpinning. Micropiles are normally made of steel with diameters of 60 to 200 mm. Installation of micropiles can be achieved using drilling, impact driving, jacking, vibrating or screwing machinery.[1] In construction, underpinning is the process of strengthening and stabilizing the foundation of an existing building or other structure. ...
Where the demands of the job require piles in low headroom or otherwise restricted areas and for specialty or smaller scale projects, micropiles can be ideal. Micropiles are often grouted as shaft bearing piles but non-grouted micropiles are also common as end-bearing piles.
Tripod piles The use of a tripod rig to install piles is one of the more traditional ways of forming piles, and 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. It can work in restricted sites (particularly where height limits exist), it is reliable, and it is usable in almost all ground conditions.
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 steel sheet piles is in retaining walls and cofferdams erected to enable permanent works to proceed. Structure in the foreground is called a mud box, a type of retaining wall built to hold flood waters in check. ...
This article does not cite any references or sources. ...
Soldier piles
A soldier pile wall using reclaimed railway sleepers as lagging 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. Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 321 KB, MIME type: image/jpeg) Green Piling, homemade, www. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 321 KB, MIME type: image/jpeg) Green Piling, homemade, www. ...
The horizontal earth pressures are concentrated on the soldier piles because of their relative rigidity compared to the lagging. Soil movement and subsidence 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.
Piled walls These methods of retaining wall 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 cost efficient temporary or permanent means of retaining the sides of bulk excavations even in water bearing strata. Image File history File links Download high resolution version (3008x2000, 1527 KB) Summary The 17th Street Canal stretches southward between Jefferson and Orleans Parishes in this aerial photo taken Sunday, September 4. ...
Image File history File links Download high resolution version (3008x2000, 1527 KB) Summary The 17th Street Canal stretches southward between Jefferson and Orleans Parishes in this aerial photo taken Sunday, September 4. ...
NOLA redirects here. ...
Lowest pressure 902 mbar (hPa; 26. ...
Structure in the foreground is called a mud box, a type of retaining wall built to hold flood waters in check. ...
When used in permanent works, these walls can be designed to accommodate vertical loads in addition to moments and horizontal forces. It has been suggested that this article or section be merged with torque. ...
In physics, force is anything that can cause a massive body to accelerate. ...
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 nature of the soils.
Secant piled 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 in order to key 'male' piles between them. 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 cantilevers, or may be propped if space and sub-structure design permit. Where party wall agreements allow, ground anchors can be used as tie backs. The cantilevered beam (green) projects from its supports (blue), balanced by the structure (red block), which supports the load (red arrow). ...
Materials
Timber As the name implies, timber piles are piles made of timber. Historically, timber has been a plentiful, locally-available resource in many areas of the globe. Today, timber piles are still more affordable than concrete or steel. Compared to other types of piles (steel or concrete), timber piles are not suitable for heavier loads. A main consideration regarding timber piles is that they should be protected from deterioration above groundwater level. Timber will last for a long time below the groundwater level. For timber to deteriorate, two elements are needed: water and oxygen. Below the groundwater level, oxygen is lacking even though there is ample water. Hence, timber tends to last for a long time below groundwater level. It has been reported that some timber piles used during 16th century in Venice still survive since they were below groundwater level. Timber can be treated with paints and various other techniques to protect from boring insects. One of the main disadvantages of timber piles is the difficulty in splicing. Splicing is the process of joining two piles to make a longer pile. Unlike steel and concrete piles, splicing is a difficult process with timber piles. Timber in storage for later processing at a sawmill Timber is a term used to describe wood, either standing or that has been processed for use—from the time trees are felled, to its end product as a material suitable for industrial use—as structural material for construction or wood...
Pipe piles Pipe piles are a type of steel driven pile foundation and are a good candidate for battered piles. PIPE can refer to PIPE (explosive) PIPE Networks Private Investment in Public Equity (PIPE) Physical Interface for PCI Express (PIPE) For other meanings, see also pipe. ...
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. The thickness of the steel should be reduced to account for corrosion, typically by 1/16 in.
The amount of corrosion for a steel pipe pile can be categorized; for a pile embedded in a non aggressive and natural soil, 0.015 mm per side per year can be assumed from the British Steel Piling Handbook. Eurocode 3 now specifies various corrosion rates based on the nature or soil conditions and pipe pile exposure.
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.
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. A tied rebar beam cage. ...
Traditional reinforced concrete is based on the use of steel reinforcement bars, rebar, inside poured concrete. ...
See also The Deep Foundations Institute (DFI) is an international membership association of contractors, engineers and suppliers in the field of design and construction of deep foundations and excavations. ...
A drilling rig is a structure housing equipment used to drill into underground reservoirs for water, oil, or natural gas, or into sub-surface mineral deposits. ...
Slurrywall excavator A slurry wall is a type of wall used to build tunnels, open cuts and foundations in areas of soft earth close to open water or with a high ground water table. ...
A pile integrity test (also known as low strain dynamic test, sonic echo test, and low strain integrity test) is one of the methods for assessing the condition of piles or shafts. ...
Dynamic load testing is a fast and effective method of assessing foundation bearing capacity that requires instrumenting a deep foundation with accelerometers and strain transducers and analyzing data collected by these sensors. ...
High strain dynamic testing is a method of testing deep foundations to obtain information about their capacity and integrity, and in some cases, to monitor their installation. ...
Crosshole sonic logging is a method to verify the integrity of drilled shafts and other concrete piles. ...
Wave equation analysis is a numerical method of analysis for the behavior of driven foundation piles. ...
Geolograph is a trademarked name for an apparatus designed to automatically record the rate of penetration and depth during a drilling operation. ...
Notes - ^ International Society for Micropiles. Retrieved on 2007-02-02.
Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ...
is the 33rd day of the year in the Gregorian calendar. ...
References - Ruwan Rajapakse, Pile Design and Construction Guide, 2002.
- Fleming, W. G. K. et al, 1985, Piling Engineering, Surrey University Press; Hunt, R. E., Geotechnical Engineering Analysis and Evaluation, 1986, McGraw-Hill.
- Caduto, 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
External links - Deep Foundations Institute
- International Society for Micropiles
- Federation of Piling Specialists (UK)
- Procedure of Installing Drilled Shaft (Bored Pile)
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