Nondestructive Testing of Deep Foundations

✍ Scribed by Bernard Hertlein, Allen Davis

• Year: 2006
• Tongue: English
• Leaves: 292
• Edition: 1
• Category: Library

✦ Synopsis

Nondestructive Testing involves the use of methods such as wave propagation, electromagnetism, electrical conductivity, and thermal conductivity to test structural integrity and thereby allow nondestructive assessment of structures and the possibility of structural failures before they occur. Nondestructive Testing of Deep Foundations covers different techniques designed to provide information about the integrity and quality of the material that makes up a deep foundation.Nondestructive Testing methods are used at all stages of a structure's life - from new construction quality control to residual lifetime prediction, and even during the monitoring of demolition. In addition, Nondestructive Testing is being increasingly specified in deep foundation projects, though often without a good understanding of its limitations and with the result that methods are often misused. In order to be able to specify an appropriate method, or to recognize an inappropriate specification, it is necessary for the engineer, specifier and/or contractor to understand the capabilities and limitations of each of the methods currently in use.Nondestructive Testing of Deep Foundations:Describes the most commonly used deep foundation construction techniques, including typical use of materialProvides a brief history of the development of commercially available nondestructive methodsSummarises each method's capabilities and limitationsActs as a one stop reference drawing together resources only previously available in conference proceedings and journal papersThis manual will prove to be a welcome addition to the bookshelf of all practitioners in civil/structural and geotechnical engineering and architecture. It will also provide a valuable insight into this highly technical field for university researchers, lecturers and postgraduate students in civil/structural and geotechnical engineering.

✦ Table of Contents

Nondestructive Testing of Deep Foundations......Page 3
Contents......Page 7
Foreword......Page 13
Preface......Page 15
About the Authors......Page 17
Acknowledgements......Page 19
Photography and Illustration
Credits......Page 21
1.1 Introduction......Page 23
1.2.1 Caveat and Acknowledgement......Page 25
1.2.2 The History......Page 26
1.3 Deep Foundation Failures and NDT......Page 32
1.3.2 Neumaier Hall, Moorhead, MN, USA......Page 33
1.3.3 Tampa Crosstown Expressway, Tampa, FL, USA......Page 35
1.3.4 Yuen Chau Kok, Shatin Area 14B, Phase 2, Hong Kong......Page 36
1.4 Deficiencies in Existing Foundations......Page 38
2 Deep Foundation Construction Methods......Page 41
2.1 Driven Piles – Timber, Steel and Concrete......Page 42
2.1.1 Drop-hammers......Page 44
2.1.2 Diesel Hammers......Page 45
2.1.3 Hydraulic Hammers......Page 46
2.1.4 Pile-driving Vibrators......Page 47
2.1.5 Direct-push Pile Installers......Page 49
2.2 Caissons and Drilled Shafts......Page 50
2.2.1 Advantages and Limitations of Drilled Shafts......Page 52
2.2.2 Advantages and Limitations of Slurry......Page 53
2.3 Diaphragm Walls, Cut-off Walls and Barrettes......Page 54
2.4 Augered, Cast-in-Place Piles......Page 55
2.4.1 Advantages and Limitations of ACIP Piles......Page 56
2.5 Micropiles or Minipiles......Page 57
2.5.1 Applications......Page 58
2.5.2 Drilled Micropile Type/Classification......Page 59
2.5.3 Relationship between Micropile Application, Design Concept and Construction Type......Page 60
2.5.4 Design Aspects......Page 61
2.6 Stone Columns and other Soil Improvement Techniques......Page 62
2.6.2 Deep Mixing......Page 63
2.6.4 Dynamic Compaction......Page 64
3
How Soils Affect the Choice
of Foundation......Page 65
4.1 Driven Piles......Page 69
4.2 Augered, Cast-in-Place Piles......Page 70
4.3.1 Dry Hole Construction......Page 72
4.3.2 Wet Hole Construction......Page 73
4.4 The Inspector’s Role......Page 77
5
A Review of Full-scale
Load-testing Techniques......Page 81
5.1.1 Reaction Systems......Page 83
5.1.2 Proof Testing......Page 85
5.1.3 Load-Transfer Tests......Page 86
5.1.5 Constant Rate of Penetration Test......Page 87
5.1.6 Bi-directional Load Test (Osterberg Cell)......Page 88
5.3 Static Load-Test Techniques – Lateral......Page 90
6.1 High-Strain Dynamic (Drop-Weight) Testing of Driven Piles......Page 93
6.1.1 The Case Method......Page 96
6.1.2 The TNO Method......Page 97
6.1.3 The Effect of Soil and Other Factors......Page 98
6.2.1 CEBTP Simbat......Page 101
6.2.2 SIMBAT Test Methodology......Page 104
6.3 Modification of Shaft Head for High-Strain Tests......Page 106
6.4 Practical Considerations for Drop-Weight Techniques......Page 109
6.4.1 Newton’s Apple......Page 110
6.5.1 The Statnamic Method......Page 111
6.5.2 The Fundex Method......Page 118
6.6 Limitations of High-Strain Dynamic Testing......Page 119
7
Low-strain Surface
Tests – Sonic Echo......Page 123
7.1 Sonic Echo (Impulse ECHO)......Page 124
7.1.2 Typical Test Procedure......Page 126
7.1.3 Data Processing and Display......Page 127
7.1.4 Effect of Impedance Change......Page 128
7.1.5 Use of Multiple Response Transducers – Double Sensor Testing......Page 132
7.1.6 Sample Specification......Page 135
8
Sonic Mobility
(Impulse Response)......Page 137
8.1.1 Characteristic Mobility......Page 144
8.2.1 Acoustic Length......Page 146
8.2.3 Pile Static/Dynamic Stiffness Relationship......Page 147
8.3 Classification of Signal Responses......Page 149
8.3.1 Type 0 signal......Page 150
8.3.3 Type 2 signal......Page 151
8.4.1 Mobility Simulation......Page 154
8.5 Time Domain–Velocity Reflectors......Page 157
8.5.1 Sample Specification......Page 158
9
The Impedance-Log Analysis......Page 159
10.2 Cross-Hole Sonic Logging......Page 165
10.2.1 Capabilities......Page 166
10.2.2 Limitations and Cost......Page 167
10.3 Cross-Hole Tomography......Page 169
10.4 Single-Hole Sonic Logging......Page 174
10.4.2 Limitations......Page 175
10.5 Gamma–Gamma Logging......Page 177
10.5.2 Limitations and cost......Page 183
10.6 Parallel Seismic Testing......Page 184
10.6.1 Capabilities......Page 185
10.6.2 Limitations and Cost......Page 186
11
Field Mock-ups of Deep
Foundations: Class-A Predictions......Page 189
12
The Reliability of Pile Shaft
Integrity Testing......Page 197
12.1 Statistical NDT Sampling Schemes......Page 198
12.2.1 Group A: Shaft Head Impact Tests......Page 200
12.2.2 Group B: Cross-Hole and Down-Hole Tests......Page 208
13
Current Research......Page 211
13.2 Electrical Methods......Page 212
13.2.2 Self-potential......Page 213
13.2.4 Resistivity (Wenner Array)......Page 214
13.2.5 Induced Polarization......Page 216
13.2.6 Cross-Borehole Radar and Electrical Resistivity Tomography......Page 217
13.3 Optical Techniques......Page 220
13.4 Guided Wave Analysis......Page 223
13.5 Statistical Analysis......Page 224
13.6 Self-Consolidating Concrete......Page 225
13.8 Automated Monitoring Systems......Page 228
13.9 Wireless Acquisition Systems......Page 229
13.10 ‘SMART’ Structures......Page 230
14
The Place of Nondestructive
Testing at the Beginning of
the 21st Century......Page 233
14.1 Nondestructive testing and load and resistence factor design......Page 236
14.2 Setting up an Effective Quality Management Program......Page 237
14.3 Who’s Testing the Tester?......Page 238
14.4 Acceptance Criteria......Page 242
14.5 Evaluating Defects......Page 243
1. General Theory......Page 245
2. Determination of Damping......Page 250
3. Determination of Harmonic Response – Mechanical Impedance......Page 251
4. Resonant frequency of an infinitely long pile......Page 254
5. Impedance input for a finite length pile with unknown mechanical impedance at its base......Page 255
Appendix II Contact Addresses......Page 257
1. Cross–Hole Sonic Logging......Page 261
4. Impulse-echo and Impulse-Response Tests......Page 262
6. Static Load Testing of Deep Foundation Shafts......Page 263
Appendix IV Sample
Specifications for NDT Methods
for Deep Foundations......Page 265
1. Sample Specification for Low-Strain Testing by Either Impulse Echo or Impulse Response......Page 266
2. Sample Specification for Cross-Hole Sonic Logging (CSL)......Page 270
References......Page 277
Index......Page 289