Deep foundations and its types
Deep foundations are useful to deliver loads out of a structure via feeble consumptive soils or fills over sturdy and incompressible soils or rocks at depth, or toward functional purposes. These foundations are set up too intensely under the finished ground surface due to their strong base bearing capacity that can cope up with the surface conditions. Here the deepness is set at >3 m under finished ground level. Deep foundations are utilized to transmit the loading to a thicker, more effective strata at depth provided unfitting soils are present adjacent to the surface.
The deep foundations are categorized as follows :-
- Buoyancy rafts (hollow box foundations)
- Shaft foundations
Basement foundations: These types of foundations belong to empty substructures which are formed to make working or storage space under ground level. The structural design is managed with their functional conditions instead of concern of the most appropriate process of combating external earth and hydrostatic pressures. These are built up in exchange for an open excavation.
Buoyancy rafts (hollow box foundations): Buoyancy rafts refer to empty substructures which are formed to create a buoyant or semi-buoyant substructure under which the net loading over the soil is decreased to the required low intensity. Buoyancy rafts are constructed so that they can be easily submerged like caissons.
Caissons foundations: Caissons refer to empty substructures which are created for being built up over or adjacent to the surface and then submerge as a single unit to their desired level.
Cylinders: Cylinders refer to minor single-cell caissons.
Shaft foundations: Shaft foundations are built up inside intense excavations supported with lining constructed in place and later on stuffed with concrete or other pre-fabricated load-bearing units.
Download - Pile foundation
Pile foundations: Pile foundations are comparatively lengthy and thin members which are built up by moving predetermined units to the optimal founding level, or by moving or drilling-in tubes to the desired depth – the tubes are stuffed with concrete earlier or throughout withdrawal or by drilling unseamed or completely or partially lined boreholes to be stuffed with concrete.
Image Courtesy: detallesconstructivos.net