DESIGN AND ANALYSIS OF DEEP FOUNDATION
WEEK 10
• DESIGN OF BORED PILE
• DESIGN OF GROUP AND RAKE PILE
• PILE SETTLEMENT
Learning Outcomes
Student should be able to:
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Design bored pile. (CO3-PO10)
Design pile group. (CO3-PO10)
Design rake pile.(CO3-PO10)
Estimate pile settlement (CO3-PO10)
Bored Pile Design
In Kenny Hill residual soil ie sedimentary soil
Fsu = KsNs
Fbu = KbNb
Chiu and Perumalawamy (1987) used Ks = 2.5 Kb = 50
When socketed into rock, the skin and end bearing shall be based
On the allowable friction and end bearing values
Structural Capacity is taken as F = 0.25fcuA
Where fcu = concrete strength at 28 days
A = cross sectional area of bored pile
Optimise by designing geotechnical capacity to equal structural
capacity
SETTLEMENT OF PILE
PILE SPACING
MINIMUN OF 3 DIAMETER CENTRE TO CENTRE OF PILE
FOR NON-CIRCULAR –CENTRE TO CENTRE SPACING
SHOULD BE AT LEAST BE SAME AS THE PERIMETER
LATERAL LOAD ON PILES
A pile resists lateral load by mobilising passive pressure of
Surrounding soil.
The soil reactions depends on
1) Stiffness of the soil
2) Stiffness of the pile
3) Fixity of the ends of the pile
Two categories:
1) Short or rigid piles
2) Long or elastic piles
Rake Pile
• Resist lateral loading in axial.