Nondestructive testing of deep foundations

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\rCredits......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\rHow Soils Affect the Choice\rof 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\rA Review of Full-scale\rLoad-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\rLow-strain Surface\rTests – 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\rSonic Mobility\r(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\rThe 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\rField Mock-ups of Deep\rFoundations: Class-A Predictions......Page 189
12\rThe Reliability of Pile Shaft\rIntegrity 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\rCurrent 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\rThe Place of Nondestructive\rTesting at the Beginning of\rthe 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\rSpecifications for NDT Methods\rfor 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