Nondestructive Testing of Deep Foundations......Page 3
Contents......Page 5
Foreword......Page 11
Preface......Page 13
About the Authors......Page 15
Acknowledgements......Page 17
Photography and Illustration
Credits......Page 19
1.1 Introduction......Page 21
1.2.1 Caveat and Acknowledgement......Page 23
1.2.2 The History......Page 24
1.3 Deep Foundation Failures and NDT......Page 30
1.3.2 Neumaier Hall, Moorhead, MN, USA......Page 31
1.3.3 Tampa Crosstown Expressway, Tampa, FL, USA......Page 33
1.3.4 Yuen Chau Kok, Shatin Area 14B, Phase 2, Hong Kong......Page 34
1.4 Deficiencies in Existing Foundations......Page 36
2 Deep Foundation Construction Methods......Page 39
2.1 Driven Piles – Timber, Steel and Concrete......Page 40
2.1.1 Drop-hammers......Page 42
2.1.2 Diesel Hammers......Page 43
2.1.3 Hydraulic Hammers......Page 44
2.1.4 Pile-driving Vibrators......Page 45
2.1.5 Direct-push Pile Installers......Page 47
2.2 Caissons and Drilled Shafts......Page 48
2.2.1 Advantages and Limitations of Drilled Shafts......Page 50
2.2.2 Advantages and Limitations of Slurry......Page 51
2.3 Diaphragm Walls, Cut-off Walls and Barrettes......Page 52
2.4 Augered, Cast-in-Place Piles......Page 53
2.4.1 Advantages and Limitations of ACIP Piles......Page 54
2.5 Micropiles or Minipiles......Page 55
2.5.1 Applications......Page 56
2.5.2 Drilled Micropile Type/Classification......Page 57
2.5.3 Relationship between Micropile Application, Design Concept and Construction Type......Page 58
2.5.4 Design Aspects......Page 59
2.6 Stone Columns and other Soil Improvement Techniques......Page 60
2.6.2 Deep Mixing......Page 61
2.6.4 Dynamic Compaction......Page 62
3
How Soils Affect the Choice
of Foundation......Page 63
4.1 Driven Piles......Page 67
4.2 Augered, Cast-in-Place Piles......Page 68
4.3.1 Dry Hole Construction......Page 70
4.3.2 Wet Hole Construction......Page 71
4.4 The Inspector’s Role......Page 75
5
A Review of Full-scale
Load-testing Techniques......Page 79
5.1.1 Reaction Systems......Page 81
5.1.2 Proof Testing......Page 83
5.1.3 Load-Transfer Tests......Page 84
5.1.5 Constant Rate of Penetration Test......Page 85
5.1.6 Bi-directional Load Test (Osterberg Cell)......Page 86
5.3 Static Load-Test Techniques – Lateral......Page 88
6.1 High-Strain Dynamic (Drop-Weight) Testing of Driven Piles......Page 91
6.1.1 The Case Method......Page 94
6.1.2 The TNO Method......Page 95
6.1.3 The Effect of Soil and Other Factors......Page 96
6.2.1 CEBTP Simbat......Page 99
6.2.2 SIMBAT Test Methodology......Page 102
6.3 Modification of Shaft Head for High-Strain Tests......Page 104
6.4 Practical Considerations for Drop-Weight Techniques......Page 107
6.4.1 Newton’s Apple......Page 108
6.5.1 The Statnamic Method......Page 109
6.5.2 The Fundex Method......Page 116
6.6 Limitations of High-Strain Dynamic Testing......Page 117
7
Low-strain Surface
Tests – Sonic Echo......Page 121
7.1 Sonic Echo (Impulse ECHO)......Page 122
7.1.2 Typical Test Procedure......Page 124
7.1.3 Data Processing and Display......Page 125
7.1.4 Effect of Impedance Change......Page 126
7.1.5 Use of Multiple Response Transducers – Double Sensor Testing......Page 130
7.1.6 Sample Specification......Page 133
8
Sonic Mobility
(Impulse Response)......Page 135
8.1.1 Characteristic Mobility......Page 142
8.2.1 Acoustic Length......Page 144
8.2.3 Pile Static/Dynamic Stiffness Relationship......Page 145
8.3 Classification of Signal Responses......Page 147
8.3.1 Type 0 signal......Page 148
8.3.3 Type 2 signal......Page 149
8.4.1 Mobility Simulation......Page 152
8.5 Time Domain–Velocity Reflectors......Page 155
8.5.1 Sample Specification......Page 156
9
The Impedance-Log Analysis......Page 157
10.2 Cross-Hole Sonic Logging......Page 163
10.2.1 Capabilities......Page 164
10.2.2 Limitations and Cost......Page 165
10.3 Cross-Hole Tomography......Page 167
10.4 Single-Hole Sonic Logging......Page 172
10.4.2 Limitations......Page 173
10.5 Gamma–Gamma Logging......Page 175
10.5.2 Limitations and cost......Page 181
10.6 Parallel Seismic Testing......Page 182
10.6.1 Capabilities......Page 183
10.6.2 Limitations and Cost......Page 184
11
Field Mock-ups of Deep
Foundations: Class-A Predictions......Page 187
12
The Reliability of Pile Shaft
Integrity Testing......Page 195
12.1 Statistical NDT Sampling Schemes......Page 196
12.2.1 Group A: Shaft Head Impact Tests......Page 198
12.2.2 Group B: Cross-Hole and Down-Hole Tests......Page 206
13
Current Research......Page 209
13.2 Electrical Methods......Page 210
13.2.2 Self-potential......Page 211
13.2.4 Resistivity (Wenner Array)......Page 212
13.2.5 Induced Polarization......Page 214
13.2.6 Cross-Borehole Radar and Electrical Resistivity Tomography......Page 215
13.3 Optical Techniques......Page 218
13.4 Guided Wave Analysis......Page 221
13.5 Statistical Analysis......Page 222
13.6 Self-Consolidating Concrete......Page 223
13.8 Automated Monitoring Systems......Page 226
13.9 Wireless Acquisition Systems......Page 227
13.10 ‘SMART’ Structures......Page 228
14
The Place of Nondestructive
Testing at the Beginning of
the 21st Century......Page 231
14.1 Nondestructive testing and load and resistence factor design......Page 234
14.2 Setting up an Effective Quality Management Program......Page 235
14.3 Who’s Testing the Tester?......Page 236
14.4 Acceptance Criteria......Page 240
14.5 Evaluating Defects......Page 241
1. General Theory......Page 243
2. Determination of Damping......Page 248
3. Determination of Harmonic Response – Mechanical Impedance......Page 249
4. Resonant frequency of an infinitely long pile......Page 252
5. Impedance input for a finite length pile with unknown mechanical impedance at its base......Page 253
Appendix II Contact Addresses......Page 255
1. Cross–Hole Sonic Logging......Page 259
4. Impulse-echo and Impulse-Response Tests......Page 260
6. Static Load Testing of Deep Foundation Shafts......Page 261
Appendix IV Sample
Specifications for NDT Methods
for Deep Foundations......Page 263
1. Sample Specification for Low-Strain Testing by Either Impulse Echo or Impulse Response......Page 264
2. Sample Specification for Cross-Hole Sonic Logging (CSL)......Page 268
References......Page 275
Index......Page 287