Pile Testing

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Pile Load Test

What is it? Why?

How is it done?

How many piles? Which piles?

When to conduct the test?

What is the maximum test load?

How to interpret test results?

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Which test method should we adopt?

Pile Testing

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Static Load Test - Test Setup

Bracket Attached to Pile

Reaction Beam Stiffeners

PlateLoad Cell Spherical Bearing

Ram

Hydraulic Jack Bourdon Gage

Dial GageLVDT

Mirror

ScaleTest Pile

GradeWire

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Kentledge Reaction System

Pile Testing

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Anchored Piles Reaction System

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Methods of Static Load Test

Pile Testing

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Pile Testing

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Results of a Maintained Load Test

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Osterberg Load Test Concept

Q

Qo

Qs

QtQo

Qt

Qs

Conventional Osterberg Cell

Expanding O-Cell

Pile Testing

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The Osterberg Cell

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Bored Pile Dimaeter = 3 m Length =67m

Max. Load = 279,000 kN

27,900 t

Pile Testing

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The Osterberg Cell

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Pile Testing

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The Osterberg Cell

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Pile Dynamic Analyzer (PDA Tests)

Pile Testing

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Pile Dynamic Analyzer (PDA Tests)

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Statnamic Load Test Setup

Pressure Chamber

Load Cell Base Plate Grouted to Foundation

Concrete or Steel Reaction Mass

Loose Granular Fill Propellant

Launching CylinderPiston BaseDisplacement Measuring Means

Pile or Drilled Shaft

Pile Testing

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Pile Testing

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Comparison of Test Duration

Pile Testing

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Comparisons between Static, Statnamic and Dynamic Pile Load Tests

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When should the pile load test be conducted?

Clay RockSand

Pile Type Driven Piles & Bored Piles

Method of Testing PDA, Statnamic, O-Cell, Static

Pile Testing

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Field Data on Friction Pile Capacity in Clay(after Vesic, 1977)

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Number of piles to be tested?

Pile Testing

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BCA/IES/ACES Advisory Note 1/03

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What is the maximum test load?

Working Load Test Qmax = 2 QALL

Preliminary or Ultimate Load Test Qmax = 2.5 or 3 QALL

QALL QULT2QALL 3QALLQ

∆

Pile Testing

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Interpretation of Failure Load

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Forms of Load-Settlement Curves(Tomlinson, 1987)

Friction pile in soft clay Friction pile in stiff clay Pile end bearing on weak porous rock

Pile Testing

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Forms of Load-Settlement Curves(Tomlinson, 1987)

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Proper Scaling of Load-Displacement Diagram

What are the failure loads of these two tests?

Proper Scaling

Pile Testing

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Determination of Qult

(after De Beer, 1967)

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Determination of Qult(after Mazurkiewics, 1974)

Pile Testing

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Determination of Qult(after Van Der Veen, 1953)

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Brinch Hansen’s 90% Criterion

Pile Testing

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Brinch Hansen’s 80% Criterion

∆u0.25 ∆u

Qu

0.8Qu

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Hirany & Kulhawy’s Method for Bored Piles(Hirany and Kulhawy, 1989)

Pile Testing

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Hirany & Kulhawy’s Method for Bored Piles(Hirany and Kulhawy, 1989)

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Tangent Intersect Method

Pile Testing

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Tangent Intersect Method

(Fuller & Hay, 1970; Butter & Hay, 1977)

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Davisson’s Method (1973)

Pile Testing

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10% Rule

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Chin’s Method(Chin, 1970)

Qu

m = 1/Qu

Pile Testing

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Pile Load Test(after Chin, 1970)

Qs = 1 / a1

Qs + Qp = 1 / a2 = Qult

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Ultimate Skin Friction and End Bearing by Chin’s Method

Pile Testing

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Comparison of Interpretation Methods(Sharma et al, 1984)

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Chin’s Stability Plot (after Chin, 1985)

Pile Testing

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Chin’s Stability Plot (after Chin, 1985)

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Chin’s Stability Plot (after Chin, 1985)

Pile Testing

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Chin’s Stability Plot (after Chin, 1985)

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Pile Instrumentation

Pile Testing

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Static Load Test on Pile with Telltales

Load (Q)

Pile Head

Telltale “A”

Telltale “B”

Telltale “A” Movement

Telltale “B”

Q1+Q2+Q3

Q1+Q2

Q1

Q1+Q2+Q3, etc.

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Load Test of Bored Pile in Old Alluvium(Chin et al, 1985)

Pile Testing

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Load Test of Bored Pile in Old Alluvium(Chin et al, 1985)

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Load Test of Bored Pile in Jurong Formation(Chang & Goh, 1988)

Pile Testing

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Load Test of Bored Pile in Old Alluvium (Chin et al, 1985)

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Load Test of Bored Pile in Old Alluvium (Chin et al, 1985)

Pile Testing

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Load Test of Bored Pile in Reclaimed Land(Wong et al, 1996)

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Load Test of Bored Pile in Reclaimed Land

(Wong et al, 1996)

Pile Testing

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Residual Stresses in Driven Piles

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Correction for Residual Stress in Driven Piles(Altaee et al, 1992)

(-ve)

(+ve)

(+ve)

Pile Testing

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Correction for Residual Stress in Driven Piles(Fellenius, 1989; Altaee et al, 1992)

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Correction for Residual Stress in Driven Piles(Fellenius, 1989; Altaee et al, 1992)

Before correction After correction