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DEEP FOUNDATION

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Deep foundation and types..

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DEEP FOUNDATION

  1. 1. PRESENTED BY….. Thamina Sharmin CEN 00805500 Beauty Akter CEN 00805502
  2. 2. DEFINITION  Deep Foundations are those  In which the depth of the foundation is very large in comparison to its width.  Which are not constructed by ordinary methods of open pit excavations.
  3. 3. FORMS OF CONSTRUCTION  Most common forms of construction pertaining to deep foundations are:  Pile Foundation (more commonly used in building construction)  Cofferdams  Caisson or Well Foundation
  4. 4. PILE FOUNDATIONS  The term ‘Pile Foundation’ denotes a construction for the foundation of a wall or pier which is supported on piles.  Where Used :  stratum of required bearing capacity is at greater depth  Advantages:  Provides a common solution to all difficult foundation site problems  Can be used for any type of structure and in any type of soil
  5. 5. PILE FOUNDATIONS
  6. 6. TYPES OF PILES BASED ON FUNCTION Classification based on Function or Use  Bearing Piles or End Bearing Piles  Friction Piles or Skin Friction Piles  Sheet Piles  Tension Piles or Uplift Piles  Anchor Piles  Batter Piles  Fender Piles  Compaction Piles
  7. 7. TYPES OF PILES BASED ON FUNCTION Bearing Piles  Driven into the ground until a hard stratum is reached.  Acts as pillars supporting the super-structure and transmitting the load to the ground. Friction Piles (Floating Piles)  Piles are driven at a site where soil is weak or soft to a considerable depth and it is not economical or rather possible to rest the bottom end of the pile on the hard stratum.
  8. 8. TYPES OF PILES BASED ON FUNCTION
  9. 9. TYPES OF PILES BASED ON FUNCTION Sheet Piles  Sheet piles are used for the following purposes:  To construct retaining walls in docks, and other marine works.  To protect erosion of river banks.  To retain the sides of foundation trenches.
  10. 10. TYPES OF PILES BASED ON FUNCTION
  11. 11. TYPES OF PILES BASED ON FUNCTION Anchor Piles  Piles are used to provide anchorage against horizontal pull from sheet piling wall or other pulling forces. Batter piles:  Piles are driven at an inclination to resist large horizontal and inclined forces. Fender piles:  Piles are used to protect concrete deck or other water front structures from the abrasion or impact caused from the ships or barges. Compaction piles:  When piles are driven in granular soil with the aim of increasing the bearing capacity of the soil, the piles are termed as compaction piles.
  12. 12. TYPES OF PILES BASED ON FUNCTION
  13. 13. TYPES OF PILES BASED ON MATERIALS Classification based on Materials 1. Timber Piles 2. Concrete Piles 3. Composite Piles 4. Steel Piles
  14. 14. TYPES OF PILES BASED ON MATERIALS Timber Piles:  Transmission of load takes place by the frictional resistance of ground and the pile surface. Advantages of Timber Piles:  Economical where timber is easily available.  Can be driven rapidly & as such saves time. Disadvantages of Timber Piles:  Liable to decay or deteriorate by salt water/insects.  Low bearing capacity.
  15. 15. TYPES OF PILES BASED ON MATERIALS
  16. 16. TYPES OF CONCRETE PILES Concrete Piles are of 3 types:  Pre-cast Piles  Cast in situ Piles  Prestressed Concrete Piles
  17. 17. TYPES OF CONCRETE PILES
  18. 18. CONCRETE PILES Advantages of Pre-cast Piles:  Very effective  Simple quality control  Improves the entire area Disadvantages of Pre-cast Piles:  Limited in length  Difficult to transport  Not suitable for densely built up area
  19. 19. CONCRETE PILES
  20. 20. Advantages of Cast-in-Situ Concrete Piles:  Not limited in length  Can be cast at any place  Requires less equipment Disadvantages of Cast-in-Situ Concrete Piles:  Quality control is difficult  Load carrying is mostly done through end bearing only  Skin frictional resistance is very low. CONCRETE PILES
  21. 21. CONCRETE PILES
  22. 22. COMPOSITE PILES  Piles of two different materials are driven one over the other, so as to enable them to act together to perform the function of a single pile.  This type of composite pile is used with the object of achieving economy in the cost of piling work.
  23. 23. STEEL PILES Types of Steel Piles:  The types of steel piles commonly used are:  H-Piles  Pipe-piles  Screw piles  Disc piles
  24. 24. STEEL PILES
  25. 25. CAUSES OF FAILURE OF PILES Unequal settlement of the sub-soil. Unequal settlement of masonry. Horizontal movement of the soil adjoining the structure. Shrinkage due to withdrawal of moisture from the soil below the foundation. Lateral pressure tending to over-turn the structure. Action of atmosphere. Lateral escape of the soil below the foundation.
  26. 26. COFFERDAMS  Cofferdams may be defined as a temporary structure constructed in a river or a lake or any other water bearing surface for excluding water form a given site to enable the building operation to be performed on dry surface. Bridge Bhairab, Bangladesh
  27. 27. Cofferdam for bridge foundations COFFERDAMS
  28. 28. TYPES OF COFFERDAM  Cofferdams may on the materials used during construction:  be divided into the following category based  Earthen cofferdam.  Rock fill cofferdam.  Single-walled cofferdam  Double-walled cofferdam.  Crib V  Cellular cofferdam.(Circular or diaphragm type)
  29. 29. TYPES OF COFFERDAM Earthen cofferdam It essentially consists of an earthen embankment built around the area to be enclosed. It is constructed in places where the depth of water is not much.
  30. 30. TYPES OF COFFERDAM
  31. 31. TYPES OF COFFERDAM Rock-fill cofferdam This construction is adopted only if the stone is easily available in the nearby areas. The stones are assembled in the required shape of the embankment and the voids are partially filled with earth and stone-chips.
  32. 32. TYPES OF COFFERDAM
  33. 33. TYPES OF COFFERDAM Single-walled cofferdam This type of cofferdam is used in places where the area to be enclosed is very small and the depth of water is more.
  34. 34. TYPES OF COFFERDAM
  35. 35. TYPES OF COFFERDAM Double-walled cofferdam Required to enclose larger areas in deep water. Larger sections of trussed struts would be necessary to resist the water pressure.
  36. 36. TYPES OF COFFERDAM
  37. 37. Crib cofferdam In deep waters where it is difficult to penetrate the guide piles or sheet piles into the hard bed below. TYPES OF COFFERDAM
  38. 38. Timber crib cofferdam TYPES OF COFFERDAM
  39. 39. TYPES OF COFFERDAM Cellular cofferdam Used for de-watering large areas in places where the depth of water may be of the order of 18 to 21 m. Mostly used during the construction of marine structures like dams, locks, whales etc. Circuler type cellular cofferdam
  40. 40. Diaphragm type cellular cofferdam TYPES OF COFFERDAM
  41. 41. CAISSONS  Caissons are water light structures made up of wood, steel or reinforced concrete, constructed in connection with excavation for foundations of bridges, piers, abutments in river and lake dock structure fore shore protection etc.  The caisson remains in its pose and ultimately becomes as integral parts of the permanent structure.
  42. 42. CAISSONS
  43. 43. TYPES OF CAISSONS  Caisson can be broadly classified into the following three types:  Open Caisson  Box Caisson (Floating Caisson)  Pneumatic Caisson
  44. 44. TYPES OF CAISSONS Open caisson with dredging wells This type of caisson has the distinction of being employed for the deepest foundation for, bridge piers, abutments and other similar structures..
  45. 45. TYPES OF CAISSONS
  46. 46. TYPES OF CAISSONS Box caisson It is closed at bottom. The caisson is cast and cured on land and when required. It is launched in water and towed to the site for sinking.
  47. 47. TYPES OF CAISSONS
  48. 48. TYPES OF CAISSONS Design and Construction of the World's Largest Pneumatic Caisson Main Pump Construction of the Higashi Ogu Sewage Treatment Plan Pneumatic caisson This type of caisson is closed at top and open (during construction) at the bottom. The water is excluded from the caisson chamber by means of compressed air.
  49. 49. THANK YOU. . .

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