Deep Foundation Design Methods

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Deep Foundation

Deign Methods

Pile SelectionGuide

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Ultimate Pile Load Capacity

Shaft Resistance

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Shaft Capacity in Clay(Alpha Method)


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Soft-stiff clay Adhesion

factors

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Nature of variation of undrained shear strength (cu) with time around a pile driven into soft clay

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Variation of Qs with time for a pile driven into soft clay(based on load test results of Terzaghi and Peck, 1967)

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Compaction of sand near driven piles (after Meyerhof, 1961)

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Unit frictional resistance for piles in sand© 2004 Brooks/Cole Publishing / Thomson Learning™

= pile critical depth

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• For z = 0 to L’fs = Kσo’tanδ =βtanδ

Where β = Kσo’

• For z = L’ to Lfs = fz=L

Qs = fs Σp ΔLWherep = perimeter of pileΔL = incremental pile length which p and fs

are taken constant

Shaft Capacity in Sand(Beta Method)

δ is the shaft soil friction angle

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Vesic Tests

Shaft Capacity in Sand(Practical Design)

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Shaft Resistance

End Bearing

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End Bearing Failure Assumptions

End Bearing Failure

Assumptions

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End Bearing Factor (Nq)

End Bearing based on SPT

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End Bearing Layered Soils

End Bearing Issues

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Cone Penetration Test (cpt)

Shaft Resistance in Clays

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Shaft Resistance in SAND

Beware of variability with different methods

End Bearing

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Piles to Rock

Piles to Rock

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Importance of Shaft Friction

Piles to Rocka, b reduction factors

(Williams & Pells 1981)

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Piles to RockEnd Bearing Parameters

Uplift Capacity

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Uplift Capacity SAND

Uplift Capacity SANDSingle Pile

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Cyclic Loading

Cyclic Stability Diagram

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Negative skin friction on a pile in the harbor of Oslo, Norway

(based on Bjerrum et al. (1969) and Wong and Teh (1995)

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Pile Groups

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Block Analysis

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Other Pile Group Cases

Effect of Weak Under Layer

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Pile Structural Design

Buckling

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Buckling

Corrosion Rates for Steel

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Corrosion Protection Methods

Deep Foundation Design Methods

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