Hướng dẫn thiết kế và thi công cọc khoan nhồi theo 22TCN272:05 và AASHTO LRFD

U.S. Department of Transportation
Federal Highway Administration

Publication No. FHWA-NHI-10-016
FHWA GEC 010
May 2010

NHI Course No. 132014

Drilled Shafts: Construction Procedures
and LRFD Design Methods
Developed following:
AASHTO LRFD Bridge Design Specifications,
4th Edition, 2007, with 2008 and 2009 Interims.


NOTICE
The contents of this report reflect the views of the authors, who are responsible for the facts and
accuracy of the data presented herein. The contents do not necessarily reflect policy of the
Department of Transportation. This report does not constitute a standard, specification, or
regulation. The United States Government does not endorse products or manufacturers. Trade
or manufacturer's names appear herein only because they are considered essential to the object of
this document.


Technical Report Documentation Page
1. Report No.

2. Government Accession No.

3. Recipient’s Catalog No.

FHWA NHI-10-016
4. Title and Subtitle

5. Report Date

DRILLED SHAFTS:
CONSTRUCTION PROCEDURES AND LRFD DESIGN METHODS
NHI COURSE NO. 132014
GEOTECHNICAL ENGINEERING CIRCULAR NO. 10
7. Author(s)

May 2010
6. Performing Organization Code

8. Performing Organization Report No.

Dan A. Brown*, Ph.D, P.E., John P. Turner**, Ph.D, P.E., and
Raymond J. Castelli, P.E.
9. Performing Organization Name and Address

10. Work Unit No. (TRAIS)

PB Americas, Inc.
One Penn Plaza, New York, NY 10119

11. Contract or Grant No.

*

Dan Brown and Associates, PLLC., Sequatchie, TN 37374
University of Wyoming, Laramie, WY 82071

**

DTFH-61-D-00011/T-07-002

12. Sponsoring Agency Name and Address

13. Type of Report and Period Covered

National Highway Institute
U.S. Department of Transportation
Federal Highway Administration, Washington, D.C. 20590

14. Sponsoring Agency Code

15. Supplementary Notes

FHWA COTR – Louisa Ward/ Larry Jones
FHWA Task Manager – Silas Nichols, P.E.
FHWA Technical Reviewers – J. Maswoswe, Ph.D, P.E.; J. DiMaggio, P.E. and F. I. S. Ibrahim, Ph.D., P.E.
See Acknowledgement for Additional Co-Authors, Contributors and Technical Reviewers
This document is a major update and revision of the 1999 FHWA Drilled Shafts manual authored by
Michael W. O’Neill and Lymon C. Reese, Publication No. FHWA-IF-99-025.
16. Abstract

This manual is intended to provide a technical resource for engineers responsible for the selection and design of drilled
shaft foundations for transportation structures. It is used as the reference manual for use with the three-day National
Highway Institute (NHI) training course No. 132014 on the subject, as well as the 10th in the series of FHWA

Geotechnical Engineering Circulars (GEC). This manual also represents a major revision and update of the FHWA
publication on drilled shaft foundations co-authored by the late Michael O’Neal and late Lymon C. Reese, published in
1988 and revised in 1999. This manual embraces both construction and design of drilled shafts, and addresses the
following topics: applications of drilled shafts for transportation structure foundations; general requirements for
subsurface investigations; construction means and methods; LRFD principles and overall design process; geotechnical
design of drilled shafts for axial and lateral loading; extreme events including scour and earthquake; LRFD structure
design; field loading tests; construction specifications; inspection and records; non-destructive integrity tests;
remediation of deficient shafts; and cost estimation. A comprehensive design example (Appendix A) is included to
illustrate the step-by-step LRFD design process of drilled shafts as foundations for a highway bridge.
17. Key Words

18. Distribution Statement

Drilled Shafts, LRFD, Foundations, Site Characterization,
Geomaterial Properties, Axial Capacity, Lateral Capacity,
Seismic, Scour, Structural Design, Construction, Soil, Rock,
Specifications, Inspection, Integrity Testing, Field Loading
Test, Remediation.
19. Security Classif. (of this report)

UNCLASSIFIED
Form DOT F 1700.7(8-72)

20. Security Classif. (of this page)

No restrictions.

21. No. of Pages

UNCLASSIFIED

Reproduction of completed page authorized

970

22. Price


CONVERSION FACTORS
Approximate Conversions to SI Units
When you know
Multiply by
To find

Approximate Conversions from SI Units
When you know
Multiply by
To find
(a) Length

inch
foot
yard
mile

25.4
0.305
0.914
1.61

millimeter

meter
meter
kilometer

millimeter
meter
meter
kilometer

0.039
3.28
1.09
0.621

inch
foot
yard
mile

0.0016
10.764
2.47
0.386

square inches
square feet
acres
square miles

0.034

0.264
35.32
1.308

fluid ounces
gallons
cubic feet
cubic yards

0.035
2.205
1.102

ounces
pounds
short tons (2000 lb)

0.2248

pound

0.021
0.145

pounds per square foot
pounds per square inch

0.0624

pounds per cubic feet

(b) Area
square inches
square feet
acres
square miles

645.2
0.093
0.405
2.59

fluid ounces
gallons
cubic feet
cubic yards

29.57
3.785
0.028
0.765

ounces
pounds
short tons (2000 lb)

28.35
0.454
0.907

pound

4.448

pounds per square foot
pounds per square inch

47.88
6.895

pounds per cubic foot

16.019

Fahrenheit temperature(oF)

5/9(oF- 32)

square millimeters
square millimeters
square meters
square meters
hectares
hectares
square kilometers
square kilometers
(c) Volume
milliliters
milliliters
liters

liters
cubic meters
cubic meters
cubic meters
cubic meters
(d) Mass
grams
grams
kilograms
kilograms
megagrams (tonne)
megagrams (tonne)
(e) Force
Newton
Newton
(f) Pressure, Stress, Modulus of Elasticity
Pascals
Pascals
kiloPascals
kiloPascals
(g) Density
kilograms per cubic meter kilograms per cubic meter
(h) Temperature
Celsius temperature(oC)
Celsius temperature(oC)

9/5(oC)+ 32

Fahrenheit temperature(oF)

Notes: 1) The primary metric (SI) units used in civil engineering are meter (m), kilogram (kg), second(s), newton (N) and pascal (Pa=N/m2).
2) In a "soft" conversion, an English measurement is mathematically converted to its exact metric equivalent.
3) In a "hard" conversion, a new rounded metric number is created that is convenient to work with and remember.


ACKNOWLEDGMENTS
This reference manual is a major update and revision of the very successful Federal Highway
Administration (FHWA) publication on drilled shaft foundations co-authored by the late Michael W.
O’Neal and late Lymon C. Reese, published in 1988 and revised in 1999. Permission by the FHWA to
include some original manuscripts and graphics from the previous versions is gratefully acknowledged.
This reference manual provides the technical contents for the NHI 132014 Course “Drilled Shafts”
developed by Parsons Brinckerhoff (PB) team including Dan Brown, John Turner, Ray Castelli. And C.
Jeremy Hung. The Drilled Shafts course is also a major update and revision of the 2003 National
Highway Institute (NHI) 132014 Course “Drilled Shafts” developed by PB and authored by late Michael
W. O’Neill, Dan Brown, & William Isenhower.
The authors would like to acknowledge the overwhelming support of Louisa Ward, NHI Program
Manager, and Silas Nichols, FHWA Task Manger, and the reviews and contributions from Jerry
DiMaggio of the Strategic Highway Research Program (SHRP2) at the National Academies. Especially
Mr. DiMaggio’s guidance and input prior to his retirement from FHWA in 2008, and his continuing
support afterward have been invaluable. In addition, the authors thank the reviews and recommendations
provided by the following individuals that served on the Technical Working Group for this project:
•
•
•
•
•
•
•

Silas Nichols, P.E.

Justice Maswoswe, Ph.D, P.E.
Firas I. S. Ibrahim, Ph.D, P.E.
Curtis Monk, P.E.
Naser Abu-Hejleh, Ph.D, P.E.
Peter Osborn, P.E.
Naresh C. Samtani, Ph.D, P.E.

FHWA
FHWA
FHWA
FHWA
FHWA
FHWA
NCS Consultants, Inc.

Furthermore, the authors thank the following organizations and their technical committees and
representatives for providing valuable information and review of the manual:
•
•
•
•

International Association of Foundation Drilling (ADSC-IAFD).
Deep Foundation Institute (DFI)
The Deep Foundations Committee of the Geo-Institute of ASCE
Transportation Research Board

In addition, the authors are grateful for the generous contributions and reviews of John Bryson and
Kwang Ro of PB, Anton Schindler of Auburn University, James Long of University of Illinois. Mr. K.
Gifford Goodhue, Jr., of KB International, reviewed an early draft of Chapter 7 and offered many useful

suggestions regarding the materials on use of drilling fluids in drilled shaft construction. Mr. Alan
Macnab, Condon-Johnson & Associates, contributed the first draft of Section 22.5 on Contractor Cost
Computations. Professor Fred H. Kulhawy, Cornell University, offered many useful suggestions and
references on revisions to the beta-method for side resistance of drilled shafts in cohesionless soils
presented in Chapter 13 and Appendix C.
Lastly, the Authors would also like to extend our gratitude to the supports provided by a number of
professionals from Parsons Brinckerhoff and Dan Brown and Associates, PLLC., including Lauren Chu
Amy Pavlakovich, Matthew Smith, Alejandra Morales, and Maria Roberts of PB for their assistance and
overall word processing and compiling.
FHWA-NHI-10-016
Drilled Shafts Manual

Acknowledgments
May 2010


This page is intentional left blank.


TABLE OF CONTENTS

LIST OF FIGURES ...................................................................................................................................xiii
LIST OF TABLES................................................................................................................................... xxiv
CHAPTER 1 - OVERVIEW - SELECTION AND USE OF DRILLED SHAFT FOUNDATIONS FOR
TRANSPORTATION STRUCTURES .....................................................................................1-1
1.1

INTRODUCTION - PURPOSE AND ORGANIZATION OF MANUAL ...............................1-1

1.2

TYPES OF DEEP FOUNDATIONS .........................................................................................1-3

1.3

DRILLED SHAFT FOUNDATIONS – DESCRIPTION AND HISTORY..............................1-3

1.4

SELECTION OF DRILLED SHAFTS....................................................................................1-10

1.4.1

Applications .........................................................................................................................1-10

1.4.2

Advantages and Limitations.................................................................................................1-15

1.5

KEYS TO SUCCESSFUL USE OF DRILLED SHAFTS ......................................................1-15

1.6

SUMMARY .............................................................................................................................1-17

CHAPTER 2 - SITE CHARACTERIZATION .........................................................................................2-1
2.1

INTRODUCTION .....................................................................................................................2-1

2.2

ROLE OF THE GEOTECHNICAL ENGINEER......................................................................2-1

2.3

SITE CHARACTERIZATION PROGRAM .............................................................................2-3

2.3.1

Data Collection ......................................................................................................................2-3

2.3.2

Field Reconnaissance.............................................................................................................2-4

2.3.3

Detailed Field Investigations .................................................................................................2-5

2.3.4

Information Required for Construction................................................................................2-22

2.4

GEOTECHNICAL REPORTS ................................................................................................2-24

2.4.1

Geotechnical Investigation Report.......................................................................................2-24

2.4.2

Geotechnical Design Report ................................................................................................2-24

2.4.3

Data Presentation .................................................................................................................2-26

2.4.4

Differing Site Conditions .....................................................................................................2-27

2.4.5

Geotechnical Baseline Report..............................................................................................2-29

2.4.6

SUMMARY .........................................................................................................................2-29

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CHAPTER 3 - GEOMATERIAL PROPERTIES......................................................................................3-1
3.1

IN-SITU TESTING ...................................................................................................................3-1

3.1.1

Standard Penetration Test ......................................................................................................3-1

3.1.2

Cone Penetration Test ............................................................................................................3-5

3.2

SOIL PROPERTIES ..................................................................................................................3-7

3.2.1

Soil Index Properties and Classification ................................................................................3-8

3.2.2

Shear Strength Properties.......................................................................................................3-8

3.2.3

Deformation Properties ........................................................................................................3-14

3.2.4

Soil Erodibility.....................................................................................................................3-16

3.2.5

In-Situ State of Stress...........................................................................................................3-18

3.2.6

Unsaturated Soil Properties..................................................................................................3-19

3.3

PROPERTIES OF ROCK........................................................................................................3-21

3.3.1

Index Properties of Rock......................................................................................................3-21

3.3.2

Properties of Intact Rock......................................................................................................3-22

3.3.3

Strength of Rock Discontinuities .........................................................................................3-23

3.3.4

In-Situ Tests for Rock ..........................................................................................................3-23

3.3.5

Rock Mass Classification.....................................................................................................3-26

3.3.6

Engineering Properties of Rock Mass..................................................................................3-28

3.4

GEOMATERIALS REQUIRING SPECIAL CONSIDERATION .........................................3-30

3.5

GEOMATERAL PROPERTIES AND LRFD.........................................................................3-31

CHAPTER 4 - GENERAL CONSTRUCTION METHODS ....................................................................4-1
4.1

INTRODUCTION .......................................................................................................................4-1

4.2

DRY METHOD OF CONSTRUCTION .....................................................................................4-2

4.3

CASING METHOD OF CONSTRUCTION...............................................................................4-6

4.4

WET METHOD OF CONSTRUCTION ...................................................................................4-12

4.5

BASE GROUTING ...................................................................................................................4-17

4.6

UNDERREAMS (BELLS) ........................................................................................................4-20

4.7

BATTERED SHAFTS...............................................................................................................4-22

4.8

SUMMARY...............................................................................................................................4-23

CHAPTER 5 - TOOLS AND EQUIPMENT ............................................................................................5-1
5.1

INTRODUCTION ....................................................................................................................5-1

5.2

DRILLING MACHINES .........................................................................................................5-1

5.2.1

Overview of Rotary Systems................................................................................................5-2

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5.2.2

Mechanical vs Hydraulic Systems .......................................................................................5-3

5.2.3

Methods of Mounting Drilling Machine ..............................................................................5-3

5.2.4

Other Excavation Systems ...................................................................................................5-9

5.2.5

Summary ............................................................................................................................5-13

5.3

TOOLS FOR EXCAVATION ...............................................................................................5-13

5.3.1

Rotary Tools .....................................................................................................................................5-13

5.3.2

Percussion and Other Tools................................................................................................5-25

5.4

OTHER TECHNIQUES .........................................................................................................5-29

5.4.1

Tools for Cleaning the Base of the Drilled Shaft Excavation ............................................5-29

5.4.2

Grouting .............................................................................................................................5-30

5.4.3

Soil Mixing.........................................................................................................................5-30

5.4.4

Concrete Liner....................................................................................................................5-31

5.5

SUMMARY ...........................................................................................................................5-32

CHAPTER 6 - CASING AND LINERS...................................................................................................6-1
6.1

TEMPORARY CASING..........................................................................................................6-1

6.1.1

Types and Dimensions .........................................................................................................6-1

6.1.2

Installation and Extraction of Temporary Casing ................................................................6-4

6.1.3

Possible Effects of Temporary Casing on Axial and Lateral Resistance ...........................6-10

6.1.4

Removing Casing after Concrete Sets................................................................................6-12

6.2

PERMANENT CASING........................................................................................................6-14

6.2.1

Types and Dimensions .......................................................................................................6-16

6.2.2

Installation of Permanent Casing .......................................................................................6-17

6.2.3

Effects of Permanent Casing on Axial and Lateral Resistance ..........................................6-17

6.2

SUMMARY ...........................................................................................................................6-18

CHAPTER 7 - DRILLING FLUIDS IN DRILLED SHAFT CONSTRUCTION.....................................7-1
7.1

INTRODUCTION AND BACKGROUND .............................................................................7-1

7.2

PRINCIPLES OF DRILLING FLUID PERFORMANCE FOR DRILLED SHAFTS ............7-2

7.2.1

Mineral Slurries....................................................................................................................7-2

7.2.2

Polymer Slurries...................................................................................................................7-5

7.2.3

Blended Slurries ...................................................................................................................7-8

7.2.4

Example Applications and Limitations of Drilling Fluids in Drilled Shaft
Construction.........................................................................................................................7-9

7.3

MATERIAL CHARACTERISTICS AND SLURRY MIX DESIGN ...................................7-10

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7.3.1

Bentonite ..............................................................................................................................7-10

7.3.1

Polymers ..............................................................................................................................7-10

7.4

CONTROL OF DRILLING FLUID DURING CONSTRUCTION ......................................7-15

7.4.1

Mixing and Handling of Mineral Slurry ............................................................................7-15

7.4.2

Mixing and Handling of Polymer Slurry............................................................................7-17

7.4.3

Sampling and Testing.........................................................................................................7-19

7.4.4

Specifications for Drilling Slurry .......................................................................................7-27

7.5

ADDITIONAL DESIGN AND CONSTRUCTION CONSIDERATIONS...........................7-29

7.5.1

Borehole Inspection Under Drilling Fluids ........................................................................7-29

7.5.2

Influence of Slurry on Axial Resistance of Drilled Shafts .................................................7-29

7.5.3

Bond with Reinforcing Steel ..............................................................................................7-35

7.5.4

Summary of Major Handling Considerations ....................................................................7-36

7.6

SELECTION OF DRILLING FLUIDS .................................................................................7-38

7.7

EXAMPLES OF PROBLEMS AND SOLUTIONS WITH CONSTRUCTION
UNDER DRILLING FLUIDS................................................................................................7-39

7.6

SUMMARY ...........................................................................................................................7-43

CHAPTER 8 - REBAR CAGES................................................................................................................8-1
8.1

INTRODUCTION .....................................................................................................................8-1

8.2

PROPERTIES OF STEEL .........................................................................................................8-1

8.3

LONGITUDINAL REINFORCING..........................................................................................8-3

8.4

TRANSVERSE REINFORCING ..............................................................................................8-5

8.5

SPLICES ....................................................................................................................................8-8

8.6

CONNECTION BETWEEN DRILLED SHAFT AND COLUMN ........................................8-10

8.7

SIZING HOOPS ......................................................................................................................8-14

8.8

CENTERING DEVICES .........................................................................................................8-15

8.9

STRENGTHENING THE CAGE TO RESIST LIFTING FORCES.......................................8-16

8.10

ARRANGEMENTS FOR LIFTING CAGE............................................................................8-17

8.11

FABRICATION AND STORAGE..........................................................................................8-19

8.12

SUMMARY .............................................................................................................................8-21

CHAPTER 9 - PLACEMENT AND DESIGN OF CONCRETE FOR DRILLED SHAFTS ...................9-1
9.1

INTRODUCTION .....................................................................................................................9-1

9.2

BASIC CHARACTERISTICS OF DRILLED SHAFT CONCRETE.......................................9-1

9.3

PLACEMENT OF CONCRETE ...............................................................................................9-2

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9.3.1

Placement in a Dry Shaft Excavation...................................................................................9-3

9.3.2

Placement in a Dry Shaft Excavation within a Cased Hole .................................................9-6

9.3.3

Placement of Concrete in a Wet Excavation ........................................................................9-8

9.3.4

Records of Concrete Volume During Placement ...............................................................9-17

9.3.5

Completion of Concrete Placement at Shaft Head .............................................................9-18

9.4

DRILLING NEAR A RECENTLY CONCRETED SHAFT...................................................9-18

9.5

BASE GROUTING .................................................................................................................9-19

9.6

CONCRETE MIX DESIGN ....................................................................................................9-21

9.6.1

Cementitious Materials ........................................................................................................9-21

9.6.2

Chemical Admixtures ..........................................................................................................9-24

9.6.3

Aggregate and Water ...........................................................................................................9-26

9.6.4

Workability ..........................................................................................................................9-28

9.6.5

Control of Concrete Temperatures......................................................................................9-30

9.6.6

Mixture Proportions .............................................................................................................9-31

9.6.7

Communication of Project Specific Requirements for the Concrete ...................................9-38

9.6.8

Strength ................................................................................................................................9-39

9.7

CONCRETE TESTS................................................................................................................9-39

9.7.1

Testing to Obtain Mixture Approval....................................................................................9-39

9.7.2

Tests at the Batch Plant........................................................................................................9-40

9.7.3 Tests at the Jobsite ...............................................................................................................9-41
9.7.4
9.7

Addition of Water at Jobsite ................................................................................................9-42

SUMMARY .............................................................................................................................9-39

CHAPTER 10 - LRFD FOR DRILLED SHAFT DESIGN.....................................................................10-1
10.1

INTRODUCTION TO LRFD ................................................................................................10-1

10.1.1

Development of Resistance Factors ................................................................................10-3

10.2

AASHTO LIMIT STATES AND LOAD COMBINATIONS ...............................................10-7

10.3

AASHTO LIMIT STATES AND DRILLED SHAFT RESISTANCES..............................10-10

10.4

RESISTANCE FACTORS FOR DRILLED SHAFTS ........................................................10-11

10.4.1

Summary of Resistance Factors...................................................................................10-11

10.4.2

Foundation Redundancy ..............................................................................................10-16

10.4.3

Comparison with Driven Piles .....................................................................................10-16

10.5

CALIBRATION TO REGIONAL CONDITIONS OR AGENCY PRACTICE..................10-16

10.5

SUMMARY .........................................................................................................................10-17

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CHAPTER 11 - DESIGN PROCESS ......................................................................................................11-1
11.1

OUTLINE OF THE OVERALL DESIGN AND CONSTRUCTION PROCESS .................11-1

11.2

SUMMARY .........................................................................................................................11-11

CHAPTER 12 - LATERAL LOADING..................................................................................................12-1
12.1

INTRODUCTION ...................................................................................................................12-1

12.2

EXAMPLES OF LATERAL LOADING ................................................................................12-1

12.2.1

Monoshaft Support for a Bridge Column.........................................................................12-1

12.2.2

Shaft Group Foundations for Bridge Structures...............................................................12-3

12.2.3

Drilled-Shaft-Supported Bridge Over Water ...................................................................12-4

12.2.4

Sound Walls, Sign Structures, High Mast Lighting .........................................................12-4

12.2.5

Foundation for a Bridge Abutment ..................................................................................12-5

12.2.6

Earth Retaining Structures ...............................................................................................12-7

12.2.7

Stabilization of a Moving Slope.......................................................................................12-8

12.3

DESIGN FOR LATERAL LOADING....................................................................................12-9

12.3.1

Design Process .................................................................................................................12-9

12.3.2

Planning Stage Estimates ...............................................................................................12-12

12.3.3

Computational Procedures and Design Methodology....................................................12-15

12.3.4

Alternative Models for Computation of Shaft Response ...............................................12-42

12.3.5

Design of Drilled Shaft Walls ........................................................................................12-47

12.3.6

Design for Drilled Shaft Foundations with Lateral Movement of Soil Mass ................12-58

12.4

SUMMARY ...........................................................................................................................12-62

CHAPTER 13 - AXIAL LOADING .......................................................................................................13-1
13.1

AXIAL LOAD TRANSFER – BASIC CONCEPTS...............................................................13-1

13.2

RELATIONSHIP TO OVERALL DESIGN PROCESS .........................................................13-2

13.3

STEP-BY-STEP PROCEDURE: DESIGN FOR AXIAL LOAD ...........................................13-3

13.3.1

Idealized Geomaterial Layer Profiles...............................................................................13-5

13.3.2

Review Limit States and Factored Axial Loads...............................................................13-7

13.3.3

Geomaterial Properties and Loading Response Mode .....................................................13-7

13.3.4

Trial Designs ....................................................................................................................13-8

13.3.5

Calculate Nominal Side and Base Resistances ..............................................................13-10

13.3.6

Evaluate Trial Design for Strength Limit States ............................................................13-28

13.3.7

Evaluate Trial Design for Service Limit States..............................................................13-28

13.3.8

Final Trial Design for Axial Compression.....................................................................13-39

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13.4

DESIGN FOR UPLIFT...........................................................................................................13-39

13.5

DESIGN FOR SCOUR...........................................................................................................13-42

13.5.1

Background and Definitions ..........................................................................................13-42

13.5.2

Design Philosophy for Scour .........................................................................................13-43

13.5.3

Analysis and Prediction of Scour...................................................................................13-44

13.5.4

Application to Drilled Shaft Design...............................................................................13-46

13.5.4

Effects of Scour on Axial Resistance.............................................................................13-47

13.6

DOWNDRAG.........................................................................................................................13-48

13.6.1

Occurrence .....................................................................................................................13-48

13.6.2

Downdrag – Basic Concepts ..........................................................................................13-50

13.6.3

Analysis of Downdrag ...................................................................................................13-51

13.6.4

Downdrag Forces ...........................................................................................................13-54

13.6.5

Limit States Evaluation Under Downdrag .....................................................................13-55

13.6.6

Strategies to Address Downdrag....................................................................................13-57

13.7

DESIGN FOR EFFECTS OF EXPANSIVE SOIL ................................................................13-58

13.7.1

Occurrence and Identification of Expansive Soils .........................................................13-58

13.7.2

Estimating the Zone of Seasonal Moisture Change .......................................................13-59

13.7.3

Design Solutions ............................................................................................................13-60

13.8

SUMMARY............................................................................................................................13-65

CHAPTER 14 - DESIGN OF GROUPS OF DRILLED SHAFTS..........................................................14-1
14.1

INTRODUCTION ....................................................................................................................14-1

14.2

GROUP VERSUS SINGLE SHAFT FOUNDATION.............................................................14-2

14.3

CONSIDERATIONS FOR SPACING .....................................................................................14-2

14.4

Group Effects on Axial Resistance ...........................................................................................14-3

14.4.1

Group Effects on Strength................................................................................................14-4

14.4.2

Settlement of Shaft Groups ..............................................................................................14-9

14.4.3

Group Effects in Rock and Cohesive IGM ....................................................................14-16

14.5

GROUP EFFECTS IN LATERAL LOADING......................................................................14-16

14.5.1

P-multiplier Concept ......................................................................................................14-16

14.5.2

Use of P-multiplier in Computer Codes..........................................................................14-18

14.5.3

Strain Wedge Approach .................................................................................................14-20

14.6 COMBINED LOADING AND COMPUTATION OF LOAD DISTRIBUTION TO
GROUP ...................................................................................................................................14-20
14.6.1

Simple Static Equilibrium..............................................................................................14-21

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14.6.2

Simple Elastic Solution..................................................................................................14-23

14.6.3

Nonlinear Computer Solution ........................................................................................14-27

14.7

SUMMARY............................................................................................................................14-28

CHAPTER 15 - DESIGN FOR EXTREME EVENTS............................................................................15-1
15.1

DESIGN FOR EXTREME EVENT SCOUR ..........................................................................15-1

15.2

DESIGN FOR EARTHQUAKE ..............................................................................................15-2

15.2.1

Framework for Analysis of Earthquake Effects...............................................................15-2

15.2.2

Time-History Analysis.....................................................................................................15-8

15.2.3

Effects of Liquefaction.....................................................................................................15-9

15.2.4

Discussion of the AASHTO Guide Specifications for LRFD Seismic Bridge
Design ............................................................................................................................15-12

15.3

DESIGN FOR EFFECTS OF ICE AND COLLISIONS .......................................................15-13

15.3.1

LRFD Framework for Extreme Event II........................................................................15-13

15.3.2

Determination of Force Effects on Drilled Shafts..........................................................15-14

15.4

DESIGN FOR COMBINED EXTREME EVENTS..............................................................15-17

15.5

SUMMARY ...........................................................................................................................15-18

CHAPTER 16 - STRUCTURAL DESIGN .............................................................................................16-1
16.1

INTRODUCTION ...................................................................................................................16-1

12.2

MATERIAL PROPERTIES ....................................................................................................16-3

16.2.1

Concrete ...........................................................................................................................16-3

16.2.2

Reinforcing Steel..............................................................................................................16-4

16.2.3

Casings.............................................................................................................................16-4

16.3

MINIMUM AND MAXIMUM AMOUNT OF LONGITUDINAL STEEL
REINFORCEMENT ................................................................................................................16-4

16.4

MINIMUM AMOUNT OF TRANSVERSE STEEL REINFORMENT.................................16-5

16.5

CONCRETE COVER AND CAGE CENTERING DEVICES ...............................................16-7

16.6

CASES WITH AXIAL LOAD ONLY ....................................................................................16-7

16.6.1

Axial Compression...........................................................................................................16-7

16.6.2

Tension Members.............................................................................................................16-8

16.6

CASES WITH AXIAL LOAD AND BENDING MOMENT .................................................16-9

16.7.1

General Concepts .............................................................................................................16-9

16.7.2

Structural Design Procedure: Longitudinal and Transverse Reinforcement..................16-12

16.7.3

Depth of Transverse Reinforcement ..............................................................................16-17

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16.7.4
16.8

Splices, Connections, and Cutoffs .................................................................................16-18

OTHER CONSIDERATIONS...............................................................................................16-19

16.8.1

Drilled Shafts with Rock Sockets ..................................................................................16-19

16.8.2

Drilled Shafts with Permanent Casing ...........................................................................16-21

16.8.3

Structural Analysis of Plain-Concrete Underreams .......................................................16-24

CHAPTER 17 - FIELD LOADING TEST ..............................................................................................17-1
17.1

GENERAL .............................................................................................................................17-1

17.1.1

Benefits and Limitations of Field Load Testing ..............................................................17-2

17.1.2

Design-Phase Load Testing Program...............................................................................17-3

17.1.3

Field Load Testing Program at the Start of Construction ................................................17-4

17.1.4

Proof Tests on Production Shafts.....................................................................................17-4

17.1.5

Field Load Testing for Research ......................................................................................17-6

17.2

LOAD TESTS TO MEASURE AXIAL RESISTANCE .......................................................17-7

17.2.1

General Considerations in Planning Axial Load Tests ....................................................17-7

17.2.2

Test Methods..................................................................................................................17-16

17.2.3

Instrumentation ..............................................................................................................17-50

17.2.4

Interpretation of Axial Test Results for Design .............................................................17-61

17.3

LOAD TESTS TO MEASURE LATERAL RESISTANCE................................................17-62

17.3.1

General Considerations in Planning Lateral Load Tests................................................17-62

17.3.2

Test Methods and Procedures ........................................................................................17-64

17.3.3

Instrumentation ..............................................................................................................17-68

17.3.4

Interpretation of Lateral Test Data.................................................................................17-72

17.4

SUMMARY .........................................................................................................................17-73

CHAPTER 18 - GUIDE DRILLED SHAFT CONSTRUCTION SPECIFICATION.............................18-1
18.1

DESIGN CONSIDERATIONS..............................................................................................18-1

18.2

QUALIFICATIONS OF DRILLED SHAFT CONTRACTORS...........................................18-2

18.3

CONSTRUCTION METHOD ...............................................................................................18-2

18.4

DRILLING FLUID ................................................................................................................18-3

18.5

LOAD TESTING ...................................................................................................................18-3

18.6

INTEGRITY TESTING .........................................................................................................18-4

18.7

CONSTRUCTION PHASE SUBSURFACE INVESTIGATIONS .......................................18-5

18.8

DRILLED SHAFT INSTALLATION PLAN ........................................................................18-5

18.9

MEASUREMENT AND PAYMENT....................................................................................18-6

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18.10

SUMMARY ...........................................................................................................................18-7

CHAPTER 19 - INSPECTIONS AND RECORDS ................................................................................19-1
19.1

RESPONSIBILITIES .............................................................................................................19-1

19.2

INSPECTION ACTIVITIES..................................................................................................19-3

19.2.1

Set-Up ..............................................................................................................................19-6

19.2.2

Casing ..............................................................................................................................19-6

19.2.3

Drilling Fluid ...................................................................................................................19-7

19.2.4

Drilled Shaft Excavation..................................................................................................19-7

19.2.5

Placement of Reinforcement............................................................................................19-9

19.2.6

Concrete Placement........................................................................................................19-10

19.2.7

Completed Drilled Shaft ................................................................................................19-12

19.3

COMMON PROBLEMS......................................................................................................19-12

19.4

DIFFERING SITE CONDITION.........................................................................................19-14

19.5

RECORDS AND FORMS....................................................................................................19-14

19.6

SUMMARY .........................................................................................................................19-15

CHAPTER 20 - TESTS FOR COMPLETED DRILLED SHAFTS........................................................20-1
20.1

INTRODUCTION ..................................................................................................................20-1

20.2

NON-DESTRUCTIVE INTEGRITY TESTS........................................................................20-1

20.2.1

Sonic Methods .................................................................................................................20-2

20.2.2

Gamma-Gamma Method..................................................................................................20-9

20.2.3

Methods Based on Analysis of Stress Waves ................................................................20-13

20.2.4

Thermal Methods ...........................................................................................................20-19

20.3

DRILLING AND CORING .................................................................................................20-20

20.3.1

Downhole Video Inspection...........................................................................................20-22

20.4

LOAD TESTING FOR DRILLED SHAFT INTEGITY EVALUATION ..........................20-22

20.5

DESIGN OF AN INTEGRITY TESTING PROGRAM AND ACCEPTANCE
CRITERIA............................................................................................................................20-23

20.5.1

When to Use NDT..........................................................................................................20-23

20.5.2

Evaluation of Defects and Acceptance Criteria .............................................................20-24

20.4

SUMMARY .........................................................................................................................20-22

CHAPTER 21 - Remediation of Deficient Drilled Shafts .......................................................................21-1
21.1

INTRODUCTION ...............................................................................................................21-1

21.2

PROBLEMS PRIOR TO COMPLETION OF CONCRETE PLACEMENT......................21-4

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21.3

Types of Deficiencies in Completed Shafts .........................................................................21-4

21.3.1

Geotechnical Strength or Servicability ............................................................................21-5

21.3.2

Structural Strength ...........................................................................................................21-6

21.4

EVALUATION....................................................................................................................21-7

21.5

REMEDIATION METHODS..............................................................................................21-8

21.5.1

Ground Improvement.......................................................................................................21-9

21.5.2

Supplemental Foundations and/or Structural Bridging....................................................21-9

21.5.3

Excavation and Replacement .........................................................................................21-13

21.5.4

Structural Enhancement .................................................................................................21-13

21.5.5

Grouting .........................................................................................................................21-14

21.6

SUMMARY .......................................................................................................................21-18

CHAPTER 22 - COST ESTIMATION ...................................................................................................22-1
22.1

GENERAL .............................................................................................................................22-1

22.2

FACTORS INFLUENCING COST .......................................................................................22-1

22.3

COMMENTARY ...................................................................................................................22-4

22.4

HISTORICAL PRICE DATA AVAILABLE THROUGH THE INTERNET ......................22-4

22.5

CONTRACTORS' COST COMPUTATION .........................................................................22-7

22.5.1

Variable Costs................................................................................................................22-8

22.5.2

Jobsite Fixed Costs ........................................................................................................22-9

22.5.3

Overhead........................................................................................................................22-9

22.5.4

Contingencies.................................................................................................................22-9

22.5.5

Markup.........................................................................................................................22-10

22.5.6

Unit Prices....................................................................................................................22-10

22.5.7

Other Considerations ...................................................................................................22-10

22.6

EXAMPLES .........................................................................................................................22-11

22.6.1

Texas............................................................................................................................22-11

22.6.2

Washington ..................................................................................................................22-11

CHAPTER 23 - REFERENCES ..............................................................................................................23-1

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LIST OF APPENDICES
APPENDIX A - DESIGN EXAMPLE FOR REPLACEMENT BRIDGE.............................................. A-1
APPENDIX B - GEOMATERIAL PROPERTIES FOR DRILLED SHAFTS IN SPECIFIC GEOLOGIC
ENVIRONMENTS....................................................................................................... B-1
APPENDIX C - COMMENTARY ON METHODS FOR COMPUTING NOMINAL AXIAL
RESISTANCE OF DRILLED SHAFTS ...................................................................... C-1
APPENDIX D - ANALYSIS OF AXIAL LOAD DEFORMATION RESPONSE ................................ D-1
APPENDIX E - DRILLED SHAFT LOAD TEST DATA...................................................................... E-1
APPENDIX F - SAMPLE DRILLED SHAFT INSPECTION FORMS, CHECKLISTS AND
TABLES .........................................................................................................................F-1
APPENDIX G - STANDARD CIDH PILE ANOMALY MITIGATION PLAN .................................... G-1

APPENDIX H - ALTERNATIVE MODELS FOR ANALYSIS OF LATERAL LOADING................. H-1

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LIST OF FIGURES
Figure 1-1
Figure 1-2
Figure 1-3
Figure 1-4
Figure 1-5
Figure 1-6
Figure 1-7
Figure 1-8
Figure 1-9
Figure 1-10
Figure 1-11
Figure 1-12
Figure 1-13
Figure 1-14
Figure 1-15
Figure 1-16
Figure 1-17
Figure 1-18

Figure 2-1
Figure 2-2
Figure 2-3
Figure 2-4
Figure 2-5
Figure 2-6
Figure 2-7
Figure 2-8
Figure 2-9
Figure 2-10
Figure 2-11
Figure 3-1
Figure 3-2
Figure 3-3
Figure 3-4
Figure 3-5
Figure 3-6
Figure 3-7
Figure 3-8
Figure 3-9
Figure 3-10
Figure 4-1
Figure 4-2
Figure 4-3
Figure 4-4
Figure 4-5
Figure 4-6
Figure 4-7
Figure 4-8

Holistic Design Example
1-2
Schematic of Axial and Lateral Resistance of a Drilled Shaft
1-4
Pneumatic Caisson for Firth of Forth Bridge
1-5
Caisson Construction for Greenville Bridge
1-6
“Caisson” Foundation Construction in Kansas City
1-6
Early “Caisson” Foundations
1-7
An Early Drilled Shaft Rig and Crew
1-8
Typical Modern Drilled Shaft Rigs
1-9
Construction of 12ft Dia. Drilled Shafts for the Main Pylon Foundation, Christopher S.
Bond Bridge, Kansas City
1-9
Construction of Drilled Shaft in Dry, Cohesive Soils
1-11
Drilled Shafts for Bridge Foundations where Small Footprint is Desirable
1-11
Drilled Shafts for Individual Column Support over Water
1-12
Group of Drilled Shafts for Large Loads
1-12
Drilled Shafts Installed for Deep Scour Problem
1-13
Drilled Shafts with Low Headroom

1-13
Drilled Shafts for Soundwall and Sign
1-14
Drilled Shafts Used to Support Earth Retaining Structures
1-14
Drilled Shaft Secant Wall and Tangent Wall
1-15
Seismic Refraction Method
2-7
ReMi Seismic Velocity Profile
2-8
Field Configuration for Resistivity Test
2-8
Resistivity Tomogram, Pennsylvania Bridge Site in Karst
2-9
Common Sampling Devices for Soil
2-14
Field Photography of Rock Core
2-17
RQD Determination from Rock Core
2-17
Example of Key to Rock Core Log
2-20
Example of Key to Rock Core Log, continued from Figure 2-8
2-21
Example of Site Investigation Plan Location Map
2-27
Example Subsurface Profile for a Bridge Site
2-28
Schematic of Common In-Situ Tests

3-2
Split-Spoon Sampler for Determination of Soil Stratigraphy
3-4
Cone Penetration Test Equipment
3-6
Soil Behavior Type Classification Chart Based on Normalized CPT and
CPTu Data
3-7
Typical Ranges of Friction Angle for Rockfills, Gravels, and Sands
3-11
Relationship Between φ' and PI of Clay Soils
3-12
Example of Soil Stress-Strain Curve and 50% Secant Modulus
3-15
Erosion Function Apparatus and Measured Erosion Function
3-18
Typical Pressure-Dilation Graphs for a Pressuremeter Test in Rock
3-25
Chart for Determination of GSI for Jointed Rock Mass
3-27
Dry Hole in Stable Soil
4-3
Cuttings from a Dry Hole Spun off the Auger
4-4
Placement of Reinforcing Cage into the Excavation
4-5
Placement of Concrete into a Dry Excavation
4-5
Dry Method of Construction
4-6

Drilling into Rock through a Cased Hole
4-7
Construction Using Casing Through Slurry-Filled Starter Hole
4-8
Construction Using Casing Advanced Ahead of Excavation
4-8

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Figure 4-9
Figure 4-10
Figure 4-11
Figure 4-12
Figure 4-13
Figure 4-14
Figure 4-15
Figure 4-16
Figure 4-17
Figure 4-18
Figure 4-19
Figure 4-20
Figure 4-21
Figure 4-22

Figure 4-23
Figure 4-24
Figure 5-1
Figure 5-2
Figure 5-3
Figure 5-4
Figure 5-5
Figure 5-6
Figure 5-7
Figure 5-8
Figure 5-9
Figure 5-10
Figure 5-11
Figure 5-12
Figure 5-13
Figure 5-14
Figure 5-15
Figure 5-16
Figure 5-17
Figure 5-18
Figure 5-19
Figure 5-20
Figure 5-21
Figure 5-22
Figure 5-23
Figure 5-24
Figure 5-25
Figure 5-26
Figure 5-27
Figure 5-28

Figure 5-29
Figure 5-30
Figure 5-31
Figure 5-32
Figure 5-33
Figure 5-34
Figure 5-35

Oscillator Rig Used to Advance Segmental Casing Ahead of the Excavation
Use of a Vibro-Hammer and Twister Bar to Advance Casing
Cutting Teeth on the Casing to Assist Penetration into the Bearing Stratum
Breach of Casing/Concrete Seal During Casing Extraction Due to Cavity
Telescoping Casing
Slurry Provides Seepage Pressure Against Excavation Surface
Slurry Drilling Process
Use of Surface Casing to Overcome Artesian Groundwater
Bottom Clean-out Bucket with Portal for Slurry Passage
Wet Hole Construction Using Full Length Casing
Reverse Circulation Drilling
Schematic of Base Grout Process
Base Grouting Systems Tied to Reinforcing Cage
Pumping Grout to the Base of the Shaft
Exhumed Shafts after Grouting
Shapes of Typical Underreams
An Early Drilled Shaft Machine and Crew
Drill Rig Terminology
Mechanical and Hydraulic Powered Drilling Machines
Truck Mounted Drilling Rigs
Crane Mounted Drilling Rig
Crawler Mounted Drilling Rigs

Excavator Mounted Drilling Machines for Restricted Overhead Conditions
Oscillator Machine
Rotator Machine
Top-Drive Reverse Circulation Drill
Reverse Circulation Cutting Heads for Top-Drive Drill
Manual Excavation in Rock
Excavation of a Diaphragm Wall or Barrette Using a Clam
Excavation of a Diaphragm Wall or Barrette Using a Hydromill
Single Flight Earth Augers
Double Flight Earth Augers
Large Diameter Auger with Double Cutting Edge
Auger with Slurry Bypass
Boulder Rooters
Rock Augers
Typical Drilling Buckets
Clean-out Buckets
Single Wall Core Barrels
Double Wall Core Barrels
Rock Cores
Full-Faced Rotary Cutters
Belling Buckets
Special Rotary Tools: Grooving Tool and “Backscratcher”
Boulder-Grabber Tool
Clam-shell Buckets
Hammergrabs
Drop Chisels and Rock Breakers
Downhole Impact Hammers
Airlift and Hydraulic Pumps for Shaft Base Cleanout
Use of Soil Mixed Columns in Conjunction with Drilled Shafts for a Wall

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4-9
4-9
4-10
4-10
4-12
4-13
4-14
4-15
4-15
4-16
4-17
4-18
4-19
4-19
4-19
4-21
5-2
5-2
5-4
5-5
5-6
5-7
5-7
5-8
5-8

5-10
5-10
5-11
5-12
5-12
5-14
5-15
5-15
5-16
5-17
5-18
5-19
5-20
5-21
5-22
5-22
5-23
5-24
5-25
5-25
5-26
5-27
5-28
5-29
5-30
5-31

Table of Contents
May 2010

Figure 5-36
Figure 6-1
Figure 6-2
Figure 6-3
Figure 6-4
Figure 6-5
Figure 6-6
Figure 6-7
Figure 6-8
Figure 6-9
Figure 6-10
Figure 6-11
Figure 6-12
Figure 6-13
Figure 6-14
Figure 6-15
Figure 6-16
Figure 7-1
Figure 7-2
Figure 7-3
Figure 7-4
Figure 7-5
Figure 7-6
Figure 7-7
Figure 7-8
Figure 7-9
Figure 7-10
Figure 7-11
Figure 7-12

Figure 7-13
Figure 7-14
Figure 7-15
Figure 7-16
Figure 7-17
Figure 7-18
Figure 7-19
Figure 8-1
Figure 8-2
Figure 8-3
Figure 8-4
Figure 8-5
Figure 8-6
Figure 8-7
Figure 8-8
Figure 8-9
Figure 8-10
Figure 8-11

Construction of Concrete-Lined Shaft
5-32
A Typical View of Stored Temporary Casing
6-2
Exceptionally Large Temporary Casings
6-3
Segmental Casing Installation with Oscillator System
6-4
Installation of Casing Joint on Standard Pipe
6-4
J Slots in Top of Casing for Use with Casing Twister

6-5
Teeth for Use in Sealing Casing into Rock
6-6
Use of Telescoping Casing
6-6
Extraction of Temporary Casing Using a Vibratory Hammer
6-8
Cutting Shoe for Segmental Casing
6-9
Adverse Effect of Casing Extended into Rock Socket
6-10
Exposed Surface of Drilled Shafts Constructed Using Oscillated and Rotated Casing 6-11
Locking Mechanism for a Removabnle Casing
6-13
Construction Joint Below the Water Surface
6-14
Example of Use of Permanent Casing
6-15
Permanent Casing Used for a Shaft Group Foundation in a River
6-16
Corrugated Metal Pipe (CMP) Used as Permanent Liner
6-17
Formation of Filter Cake and Positive Effective Pressure, Mineral Slurry in Sand
Formation
7-3
Mineral Slurry Plates in Pores of Open-pored Formation
7-4
PAM Polymer Slurry
7-6
Stabilization of Borehole by the Use of Polymer Drilling Slurries

7-7
Schematic Diagram of Unit for Mixing and Treating Mineral Slurry
7-16
Field Mixing Polymer Slurry by Circulating Between Tanks
7-18
Techniques for Hanling Polymer Slurry
7-18
Device for Downhole Sampling of Slurry
7-20
Mud Density Balance for Field Measurement of Slurry Density
7-21
Marsh Funnel Test for Field Evaluation of Slurry Viscosity
7-22
Schematic of Slurry Viscometer
7-22
Interpretation of Data from a Viscometer Test
7-23
Photograph of Sand Content Test Apparatus
7-25
Average Load Transfer in Side Shear for Different Construction Methods
7-34
Mobilized Unit Side Resistance in Lower Fort Thompson Formation Rock Sockets 7-35
Placing Concrete through Heavily-Contaminated Slurry
7-40
Placing Casing into Mineral Slurry with Excessive Solids Content
7-40
Pulling Casing with Insufficient Head of Concrete
7-41
Placing Concrete where Casing was Improperly Sealed
7-42

GR75 Reinforcement Cage Being Assembled, Showing Threaded Couplers
8-3
View of a Rebar Cage Being Assembled, Showing Longitudinal Steel
8-4
View of Bundles of No.18 Rebar in a Drilled Shaft Cage
8-5
Transverse Ties and Spiral Steel, Showing Hook Anchors and Spiral Laps
8-6
Possible Distortion of Poorly Assembled Cage Due to Pickup Forces or Hydraulic Forces
from Fresh Concrete
8-7
Examples of Inadequate Flow of Concrete Through Tightly Spaced Spiral
Reinforcement
8-7
Bundled Hoops Used to Improve Flow of Concrete Through Transverse
Reinforcement
8-8
Constructability Problem From Excessive Concentration of Lap Splices
8-9
Bar Couplers Used to Construct Splices
8-9
Adjustment to Drilled Shaft Reinforement for Alignment to Column Cage
8-10
Type I and II Connections
8-11

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Figure 8-12
Figure 8-13
Figure 8-14
Figure 8-15
Figure 8-16
Figure 8-17
Figure 8-18
Figure 8-19
Figure 8-20
Figure 8-21
Figure 8-22
Figure 8-23
Figure 8-24
Figure 9-1
Figure 9-2
Figure 9-3
Figure 9-4
Figure 9-5
Figure 9-6
Figure 9-7
Figure 9-8
Figure 9-9
Figure 9-10
Figure 9-11
Figure 9-12

Figure 9-13
Figure 9-14
Figure 9-15
Figure 9-16
Figure 9-17
Figure 9-18
Figure 9-19
Figure 9-20
Figure 9-21
Figure 9-22
Figure 9-23
Figure 9-24
Figure 9-25
Figure 9-26
Figure 9-27
Figure 9-28
Figure 9-29
Figure 10-1
Figure 10-2
Figure 11-1
Figure 12-1

Washington DOT Type II Connection Detail
8-12
Construction of a Type II Connection Detail over Water
8-13
Splice Cage Used to Fabricate Column to Shaft Connection
8-14
Sizing Hoop Assembly
8-14

Roller Centralizers on Reinforcing Cage
8-15
Chairs for Base of Reinforcing Cage
8-16
Transverse and Longitudinal Stiffeners for Temporary Strengthening of the Rebar
Cage
8-17
Transverse Stiffeners Attached with Tack-Welds to Sizing Hoops
8-17
Photograph of Rebar Cage Being Lifted Improperly
8-18
Photograph of Rebar Cage Being Lifted Properly
8-18
Photograph of Rebar Cage Being Lifted with a Tipping Frame
8-19
Photograph of Rebar Cage Being Delivered to Site
8-20
Photograph of Rebar Cage Being Assembled Over the Shaft Excavation
8-20
Free Fall Concrete Placement in a Dry Excavation
9-3
Placement into a Dry Excavation Using a Drop Chute
9-4
Excessive Seepage Precludes Free Fall Placement of Concrete
9-5
Concrete Pressure Head Requirement During Casing Extraction
9-6
Slurry Displaced from Annular Space during Casing Extraction
9-7
Concrete Placement with Telescoping Casing

9-8
Tremie Must be Clean
9-9
Solid Tremie Pipes
9-10
Assembly of Segmental Tremie for Concrete Placement
9-10
Closure Plates for Closed Tremie
9-11
Control of Tremie to Establish Concrete Head
9-12
Breach of Tremie Due to Failure to Establish Concrete Head
9-12
Schematic of Concrete “Vent” Due to Loss in Concrete Mix Workability During Tremie
Placement
9-13
Effects of Loss in Concrete Mix Workability During Tremie Placement
9-14
Pump Line Operations for Underwater Concrete Placement
9-15
Exposed Bottom Surface of an Exhumed Drilled Shaft
9-16
Example Concrete Volume Plots
9-17
Over-pour of the Shaft Top Until Clean Concrete is Revealed
9-18
Sleeve Port System for Distribution of Grout to the Base of the Shaft
9-20
Good Passing Ability is Required to Flow through Reinforcement
9-21

Simulated Effects of using SCMs on the Maximum Concrete Temperature Reached 9-23
The Effect of Different Initial Mixture Temperatures on the Temperature Development
During Adiabatic Conditions
9-30
Slump Loss Relationship from a Trial Mixture Design
9-33
Concrete with Insufficient Workability for Use in Drilled Shafts
9-36
Concrete with High Workability but with Improper Mixture Design for Tremie
Placement
9-37
Drilled Shaft Concrete with High Workability - 9.0 inch Slump
9-37
Drilled Shaft Concrete with Moderate Workability - 6.5 inch Slump
9-37
Self-consolidating Concrete with a 20 in. Slump Flow Used in Drilled Shaft
Construction
9-38
3
9-40
Worksite Concrete Batch Plant Capable of Batching 130 yd /hr
Reliability Concepts
10-5
Structural Analysis of Bridge Used to Establish Foundation Force Effects
10-9
Drilled Shaft Design and Construction Process
11-2
Single Column Piers with Monoshaft Foundations
12-2

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Figure 12-2
Figure 12-3
Figure 12-4
Figure 12-5
Figure 12-6
Figure 12-7
Figure 12-8
Figure 12-9
Figure 12-10
Figure 12-11
Figure 12-12
Figure 12-13
Figure 12-14
Figure 12-15
Figure 12-16
Figure 12-17
Figure 12-18
Figure 12-19
Figure 12-20
Figure 12-21
Figure 12-22

Figure 12-23
Figure 12-24
Figure 12-25
Figure 12-26
Figure 12-27
Figure 12-28
Figure 12-29
Figure 12-30
Figure 12-31
Figure 12-32
Figure 12-33
Figure 12-34
Figure 12-35
Figure 12-36
Figure 12-37
Figure 12-38
Figure 12-39
Figure 12-40
Figure 12-41
Figure 12-42
Figure 12-43
Figure 12-44
Figure 12-45
Figure 13-1
Figure 13-2
Figure 13-3
Figure 13-4
Figure 13-5

Monoshaft Foundations Used by Caltrans

12-2
Example of a Drilled Shaft Group Foundation for a Bridge
12-3
Drilled Shafts for Bridge Over Water, Somerset, KY
12-4
Elevation View of an Overhead Sign Structure
12-5
Sketch of Foundation for a Bridge Abutment
12-6
Drilled Shaft Abutment Foundations
12-6
Arch Bridge
12-7
Drilled Shaft Secant Wall and Tangent Wall
12-7
Drilled Shaft Foundation for Retaining Wall using Soldier Piles and Precase Panels 12-8
Drilled Shafts for Stabilizing a Slide
12-8
Analysis of Drilled Shafts in Moving Soil
12-9
Drilled Shaft Design Process for Lateral Loads
12-10
Equivalent Length Concept for Preliminary Design
12-13
Equivalent Length of Shaft for Preliminary Design of Single Shaft Foundation
12-13
Model of a Drilled Shaft Foundation Under Lateral Loading Showing
Concept of Soil
12-17
Definition of Terms in Equations 12-6 and 12-7

12-21
Variation of EI of a Drilled Shaft Cross Section with Bending Moment and Axial 12-22
Stress-Strain Model for Concrete
12-23
Stress-Strain Model for Steel Reinforcement
12-23
Simple Lateral Load Example, Factored Loads Shown
12-27
Results of Analyses of Geotechnical Strength for Simple Example
12-28
Results of Analyses of Structural Strength and Serviceability for Simple Example 12-29
Bending Moment vs. Curvature for Simple Example
12-30
EI vs. Bending Moment for Simple Example
12-30
Conceptual p-y Curve for Cohesive Soil
12-31
Conceptual p-y Curve for Stiff Clay in the Presence of Free Water
12-32
Conceptual p-y Curve for Cohesionless Soil
12-33
Proposed p-y Criterion for Weak Rock
12-34
Proposed p-y Criterion for Strong Rock
12-35
Example for Sensitivity Analysis of Stratigraphy
12-36
Basic Strain Wedge in Uniform Soil
12-38
Deflection Pattern of Laterally Loaded Long Shaft and Associated Strain

12-38
Proposed Geometry of Compound Passive Wedge
12-39
Pushover Analysis of a Column Supported on a Drilled Shaft
12-41
Broms Earth Pressures for Cohesive Soils
12-43
Broms Pressure, Shear, Moment Diagrams for Cohesive Soils
12-43
Broms Pressure, Shear, Moment Diagrams for Cohesionless Soils
12-46
Secant, Tangent, and Soldier Pile Walls
12-47
Geometry for Drilled Shaft Wall
12-49
Simplified Earth Support Diagram for a Cantilever Wall using Effective Stress
Strength
12-53
Example of Drilled Shaft Wall Problem
12-53
Earth Pressure Diagram for Drilled Shaft Wall Example Problem
12-55
Analysis of Drilled Shafts in Moving Soil
12-59
Spreading the Displaces Foundation with Soil
12-60
Generalized Load Transfer Behavior of Drilled Shaft in Compression
13-2
Flow Chart, Recommended Procedure for Axial Load Design
13-4

Idealized Geomaterial Layering for Computation of Compression Resistances
13-6
Frictional Model of Side Resistance, Drilled Shaft in Cohesionless Soil
13-11
Subsurface Profile and Drilled Shaft for Illustrative Example 13-1
13-14

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Figure 13-6
Figure 13-7
Figure 13-8
Figure 13-9
Figure 13-10
Figure 13-11
Figure 13-12
Figure 13-13
Figure 13-14
Figure 13-15
Figure 13-16
Figure 13-17
Figure 13-18
Figure 13-19

Figure 13-20
Figure 13-21
Figure 13-22
Figure 13-23
Figure 13-24
Figure 14-1
Figure 14-2
Figure 14-3
Figure 14-4
Figure 14-5
Figure 14-6
Figure 14-7
Figure 14-8
Figure 14-9
Figure 14-10
Figure 14-11
Figure 14-12
Figure 14-13
Figure 14-14
Figure 14-15
Figure 15-1
Figure 15-2
Figure 15-3
Figure 15-4
Figure 15-5
Figure 15-6
Figure 15-7
Figure 16-1
Figure 16-2
Figure 16-3

Figure 16-4
Figure 16-5

Soil Profile and Trial Shaft for Illustrative Example 13-2
13-18
Base Resistance Factor for Rock
13-22
Ground Profile and Trial Shaft for Illustrative Example 13-3
13-26
Factor α for Cohesive IGM
13-27
Normalized Load-Displacement Curve, Drilled Shaft in Axial Compression
13-30
Idealized Subsurface Profile and Drilled Shaft Trial Dimensions
13-33
Mechanistic Model of Axially Loaded Drilled Shaft
13-38
Axially Loaded Shaft in Rock or Very Hard Geomaterial, Elastic Analysis
13-39
Typical Loading Combination Resulting in Uplift
13-41
Forces and Idealized Geomaterial Layering for Computation of Uplift Resistance 13-41
Components of Scour Affecting Bridge Supports on Deep Foundations
13-43
Flow Charts for Hydrology, Hydraulics, and Scour Analysis
13-45
Illustration of Scour Prism and Effects on Drilled Shaft
13-47
Downdrag on a Drilled Shaft Caused by Soil Settlement
13-50

Common Sources of Downdrag at Drilled Shaft Supported Bridge Abutments
13-50
Mechanics of Downdrag
13-51
Idealized Example of a Drilled Shaft in Expansive Ground
13-60
Use of embedded structural shape with weak concrete, Procedure B
13-62
Axial Force Effecrs and Resistances for Design of Drilled Shafts by Procedure C 13-63
Group of Drilled Shafts During Construction of the Benetia-Martinez Bridge near
San Francisco
14-1
Group Versus Single Shaft
14-2
Overlapping Zones of Influence in a Frictional Pile Group
14-4
Block Type Failure Mode
14-6
Efficiency (η) vs. Center-to-Center Spacing (s), Normalized by Shaft Diameter (Bshaft),
for Under Reamed Model Drilled Shafts in Compression in Moist, Silty Sand.
14-7
Relative Unit Side and Base Resistances for Model Single Shaft and Typical Shaft in a
Nine-Shaft Group in Moist Alluvial Silty Sand
14-7
Axial Resistance from FE Model Results of Bored Pile Groups
14-8
Deeper Zone of Influence for End Bearing Shaft Group than for a Single Shaft
14-10
Equivalent Footing Concept for Pile Groups
14-13

Pressure Distribution Below Equivalent Footing for Pile Group
14-14
Typical e versus Log p Curve from Laboratory Consolidation Testing
14-15
The P-Multiplier Concept
14-17
Example Plots of Lateral Load Response by Row Position
14-19
Simple Static Analysis of a 2 x 2 Group
14-21
Simple Static Analysis of a 2 x 3 Group
14-23
Flowchart of Major Steps for Analysis of Drilled Shafts for Earthquake Effects
15-4
Response Spectrum for Determination of Seismic Response Coefficient
15-6
Relationship Between Connected Blow Count and Undrained Residual Strength (Sr)
from Case Studies
15-11
Design Impact Force, Ship Colliding with Bridge Pier
15-16
Response Spectrum for Determination of Seismic Response Coefficient
15-12
Relationship Between Corrected Blow Count and Undrained Residual Strength (Sr)
from Case Studies
15-17
Design Impact Force, Ship Colliding with Bridge Pier
15-21
Flow Chart for Structural Design
16-2

Transverse (Confinement) Reinforcement Details
16-7
Interaction Diagram for a Reinforced Concrete Column (a-h)
16-9
Nominal and Factored Interaction Diagrams
16-11
Variation of φ with Net Tensile Strain, εt and dt/c for Grade 60 Reinforcement
16-12

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Figure 16-6
Figure 16-7
Figure 16-8
Figure 16-9
Figure 16-10
Figure 16-11
Figure 16-12
Figure 16-13
Figure 17-1
Figure 17-2
Figure 17-3
Figure 17-4

Figure 17-5
Figure 17-6
Figure 17-7
Figure 17-8
Figure 17-9
Figure 17-10
Figure 17-11
Figure 17-12
Figure 17-13
Figure 17-14
Figure 17-15
Figure 17-16
Figure 17-17
Figure 17-18
Figure 17-19
Figure 17-20
Figure 17-21
Figure 17-22
Figure 17-23
Figure 17-24
Figure 17-25
Figure 17-26
Figure 17-27
Figure 17-28
Figure 17-29
Figure 17-30
Figure 17-31
Figure 17-32
Figure 17-33
Figure 17-34

Figure 17-35
Figure 17-36
Figure 17-37
Figure 17-38
Figure 17-39

Illustration of Terms bv, dv and dc for Circular Sections
16-14
SampleElevation of Drilled Shaft without Casing
16-16
Typical Sections without Casing
16-17
Comparison of Moment and Shear for a Cantilevered Column and a Socketed Drilled
Shaft
16-20
Sample Elevation with Casing
16-22
Typical Section with Casing
16-23
Typical Underream
16-24
Tensile Stress Contours for Flat-bottom Bell
16-25
Kentledge Static Load Tests with Bi-directional Test and Rapid Load Test
17-1
Proof Test on Production Shafts can Verify Axial Resistance
17-5
Instrumental Research Load Tests
17-7
Observation of Test Shaft Excavation Helps Define Geologic Condition

17-10
Example Borehole Calipers & Logs; Mechanical and Sonic
17-12
Unit Side Shear vs Displacement for Drilled Shaft Sockets in Rock of Moderate
Roughness with qu = 450 psi
17-14
Computed Relationship Between Shaft Diameter and Maximum Unit Side Shear
Resistance for Rock Sockets
17-15
“Chicago Method” Load Test using Bi-directional Cell
17-15
Conventional Static Load Test on a Drilled Shaft
17-17
4,000 ton Capacity Reaction System
17-18
5,700 ton Capacity Load Test in Taiwan
17-18
Bi-DirectionalTesting Schematic
17-20
Example Test Result from Bi-Directional Test
17-21
O-Cell Test with Added Reaction System
17-21
Multiple-Level Arrangement for O-cells
17-22
Single O-Cell and Multiple O-Cell Assembly and Multi-Level O-Cell Assembly 17-23
Construction Of Equivalent Top-Loaded Settlement Curve
17-26
Top Down and O-Cell Load Test at a Soil Site
17-27

Effect of “Shoulder” at Top of Rock
17-27
Average Compressive Load in Shaft During Top Down and O-Cell Loading
17-28
17-28
Analytical Model Results for O-Cell Loading in a Rock Socket
Analytical Model Results for O-Cell Loading in a Rock Socket
17-29
Comparison of Rapid Load and Hammer Blow
17-31
Conceptual Sketch of the Statnamic Rapid Load Test
17-32
Statnamic Loading Devices
17-32
Schematic Diagram of Statnamic Loading Apparatus
17-33
Statnamic Loading Apparatus
17-34
Measurements of Force and Displacement During Statnamic Loading
17-34
Force-Time Measurements for a Drilled Shaft
17-35
Single Degree of Freedom Model of a Statnamic Test
17-36
Statnamic Load versus Displacement
17-37
Computed Damping Coefficient, c
17-37
Segmental Unloading Point Method
17-38

Comparative Static and Statnamic Load Tests for Drilled Shafts
17-39
Dynamic Load Test of Drilled Shafts using Drop Weight and Pile Hammer
17-40
Transducers for Measurement of Force and Acceleration Photos courtesy of Pile
Dynamics, Inc.
17-42
Signal Matching Concept
17-43
Computational Model of Shaft/Soil System
17-44
Factors Most Influencing CAPWAP Force Matching
17-45

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