1 / 52

PILE FOUNDATIONS

PILE FOUNDATIONS. TOPICS. Introduction Type of pile Estimating pile length Load transfer mechanism Pile capacity Mayerhof’s method for estimating Qp Vesic’s method for estimating Qp Coyle and Castello’s method for estimating Qp in sand. Correlation of calculating Qp with SPT

asapp
Download Presentation

PILE FOUNDATIONS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. PILE FOUNDATIONS

  2. TOPICS • Introduction • Type of pile • Estimating pile length • Load transfer mechanism • Pile capacity • Mayerhof’s method for estimating Qp • Vesic’s method for estimating Qp • Coyle and Castello’s method for estimating Qp in sand. • Correlation of calculating Qp with SPT • Frictional Resistance (Qs) in sand • Frictional Resistance in clay • Elastic settlement of piles • Negative skin friction

  3. Introduction Why we need piles. Upper soil layers are highly compressible and too weak to support the load transmitted by the superstructure Bedrock is not encountered at a reasonable depth below the ground surface Foundation subjected to horizontal forces piles are extended beyond the active zone, which is where swelling and shrinking occur. Foundation for structure that subjected to uplifting forces. Bridge abutments and piers are usually constructed over pile foundations to avoid the loss of bearing capacity

  4. Type of Piles • Steel Piles • Concrete piles • Timber piles • Composite piles

  5. Type of Piles Steel Piles • Normally H and I-section • Steel piles are spliced by welding or by riveting • Steel piles can be fitted with driving points or shoes • Steel piles may be subject to corrosion. Additional thickness need to off-set the effect of corrosion. • Usual length: 15 m to 60 m • Usual load: 300 kN to 1200 kN

  6. Type of Piles Concrete Piles • Can be divided into two type; precest pile and cast-in-situ pile Precast Pile • prepared by using ordinary reinforcement, and they can be square or octagonal in cross section • Usual length: 10 m to 15 m • Usual load: 300 kN to 3000 kN

  7. Type of Piles Concrete Piles • Can be divided into two type; precest pile and cast-in-situ pile Cast-in-situ pile • built by making a hole in the ground and then filling it with concrete. • divided into two broad categories: (a) cased and (b) uncased Cased pile Un-cased pile

  8. Type of Piles Timber piles • The maximum length of most timber piles is 10 to 20 m • Timber piles cannot withstand hard driving stress • if splicing is necessary, it can be done by using pipe sleeves • Timber piles can stay undamaged indefinitely if they are surrounded by saturated soil. However, in a marine environment, timber piles are subject to attack by various organisms and can be damaged extensively in a few months. • The life of the piles may be increased by treating them with preservatives

  9. Type of Piles Composite piles • The upper and lower portions of composite piles are made of different materials • The upper and lower portions of composite piles are made of different materials • Forming proper joints between two dissimilar materials is difficult, and for that reason, composite piles are not widely used.

  10. Estimating Pile Length

  11. Estimating Pile Length Under certain circumstances, piles are driven in granular soils to achieve proper compaction of soil close to the ground surface. These piles are called compaction piles.

  12. Load Transfer Mechanism

  13. Load Transfer Mechanism

  14. Equation for Estimating Pile Capacity

  15. Equation for Estimating Pile Capacity

  16. Mayerhof’s method for estimating Qp

  17. Mayerhof’s method for estimating Qp

  18. Mayerhof’s method for estimating Qp

  19. Vesic’s method for estimating Qp

  20. Vesic’s method for estimating Qp

  21. Vesic’s method for estimating Qp

  22. Vesic’s method for estimating Qp

  23. Coyle and Castello’s method for estimating Qp in sand.

  24. Correlation of calculating Qp with SPT

  25. Frictional Resistance (Qs) in sand

  26. Frictional Resistance (Qs) in sand

  27. Frictional Resistance (Qs) in sand For high displacement driven pile For low displacement driven pile

  28. Frictional Resistance in clay

  29. Frictional Resistance in clay

  30. Frictional Resistance in clay

  31. Elastic settlement of piles

  32. Elastic settlement of piles

  33. Elastic settlement of piles

  34. Negative Skin Friction

  35. Negative Skin Friction

  36. Example

  37. Example

  38. Example

  39. Example

  40. Example

  41. Example

  42. Example

  43. Example

  44. Example

  45. Example

  46. Example

  47. Example

  48. Example

  49. Example

  50. Example

More Related