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 material Provides a brief history of the development of commercially available nondestructive methods Summarises each method's capabilities and limitations Acts as a one stop reference drawing together resources only previously available in conference proceedings and journal papers This 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. 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
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 Testingof 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 Testingof Deep Foundations:
- Describes the most commonly used deep foundation construction techniques, including typical use of material
- Provides a brief history of the development of commercially available nondestructive methods
- Summarises each method's capabilities and limitations
- Acts as a one stop reference drawing together resources only previously available in conference proceedings and journal papers
This 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.
