Nondestructive Testing of Deep Foundations

BERNARD H. HERTLEIN, M.ASCEBernard Hertlein started his professional career as a mechanical engineering student but soon realized that he had a natural affinity for electronics. After working professionally with automotive electronic systems and pursuing audio engineering as a hobby for several years, he migrated through audio engineering to instrumentation of civil engineering structures and finally to nondestructive testing. After joining Testconsult, the English subsidiary of the French National Center for Building and Civil Engineering Research (CEBTP), Mr Hertlein became deeply involved with the development of both the software and the hardware for several nondestructive test techniques for deep foundations that are now in common use worldwide. He worked on construction testing projects throughout Europe, HongKong, parts of North Africa and the United States, eventually settling in the United States, where he and Allen Davis introduced the Cross-hole Sonic-Logging technique, the Parallel-Seismic test and the Impulse-Response (Sonic-Mobility) test in the mid 1980s.In 1992, Mr Hertlein joined STS Consultants, based inVernon Hills, Illinois, where he has continued to design and build test equipment and research new applications for the test techniques that he had helped to introduce to the United States. Mr Hertlein is an active member of several key professional societies. At the time of writing this book, he is a member of the American Society of Civil Engineers, Chairman of the Nondestructive and In-place Testing Committee of the American Society for Testing and Materials (ASTM C9-64), Chairman of the Testing and Evaluation Committee of the Deep Foundations Institute, and Secretary of the Nondestructive Testing Committee of the American Concrete Institute (ACI 228). He also serves as a member of ACI Committee 336: Footings, Mats and Drilled Piers, ASTM Committee C9-47:Self-Consolidating Concrete, D18-11: Deep Foundations and G9-14: Corrosion of Reinforcing Steel. Mr Hertlein has written numerous conference papers and journal articles. He is a regular member of the faculty for the International Association of Foundation Drilling(ADSC-IAFD) Drilled Shaft Inspector's School and a frequent lecturer at other educational seminars presented byACI International, ADSC regional chapters, the ASCE Geo-Institute and the Deep Foundations Institute.ALLEN G. DAVIS, PH.D., D.SC., PEAllen Davis qualified as a geologist and his first career was as prospector for De Beers Corporation in Central Africa. He then converted to Civil Engineering through Geotechnics, gaining his Ph.D. from Birmingham University, UK in that subject. He has had Academic, Research and Industrial experience in fairly equal proportions, including: Professor at the University of Birmingham, UK, for 10 years. Head of the Geotechnical and Highways Research Division, National Center for Building and Civil Engineering Research (CEBTP), Paris, France, for 8 years. Technical and Managing Director, Testconsult CEBTP (UK) for 8 years. He was one of the founding members of Testconsult in 1974. Principal Engineer, STS Consultants, Ltd and Manager for NDE, Madsen, Kneppers Associates, Chicago, Illinois and Salt Lake City, Utah, USA for 6 years. Senior Principal Engineer, Construction Technology Laboratories, Inc. (CTL), Skokie, Illinois, USA for the last 6 years.At the time of writing this book he was Manager of Nondestructive Evaluation at CTL in Skokie, Illinois. His special interests included vibration problems and realtime data acquisition from dynamic testing of concrete foundations and structures, and he was a member and past Chairman of Committee 228 (Nondestructive Testing of Concrete) of the American Concrete Institute and also a member ofASTMCommittee Nondestructive and In-place Testing. He has published over 80 technical articles and publications to date in the fields of Civil Engineering and Building, Transportation and Materials Resources. Eleven Ph.D. research students (seven in France, four in England) have graduated under his supervision, and he was awarded the degree of Doctor of Science by Birmingham University in 1980. His contributions to the concrete industry and to the work of the ACI were recognized at the October 2004 meeting of the ACI in San Francisco, where it was announced that he had been elected a Fellow of the Institute. Unfortunately ill-health had prevented him from going to San Francisco, and he passed away suddenly at his home a few hours after learning of the fellowship announcement. Rest in peace, old chum.

• FOREWORD xiPREFACE xiiiABOUT THE AUTHORS xvACKNOWLEDGEMENTS xviiPHOTOGRAPHY AND ILLUSTRATION CREDITS xix1 INTRODUCTION AND BRIEF HISTORY 11.1 Introduction 11.2 A Brief History of Deep Foundations and the Advent of NDT 31.3 Deep Foundation Failures and NDT 101.4 Deficiencies in Existing Foundations 162 DEEP FOUNDATION CONSTRUCTION METHODS 192.1 Driven Piles – Timber, Steel and Concrete 202.2 Caissons and Drilled Shafts 282.3 Diaphragm Walls, Cut-off Walls and Barrettes 322.4 Augered, Cast-in-Place Piles 332.5 Micropiles or Minipiles 352.6 Stone Columns and other Soil Improvement Techniques 403 HOW SOILS AFFECT THE CHOICE OF FOUNDATION 434 TRADITIONAL, VISUAL AND NEW INSPECTION METHODS FOR DEEP FOUNDATION CONSTRUCTION 474.1 Driven Piles 474.2 Augered, Cast-in-Place Piles 484.3 Drilled Shafts 504.4 The Inspector's Role 555 A REVIEW OF FULL-SCALE LOAD-TESTING TECHNIQUES 595.1 Static Load-Test Techniques – Axial Compression 615.2 Static Load-Test Techniques – Axial Tension 685.3 Static Load-Test Techniques – Lateral 686 HIGH-STRAIN TESTING FOR CAPACITY AND/OR INTEGRITY 716.1 High-Strain Dynamic (Drop-Weight) Testing of Driven Piles 716.2 High-Strain Testing of Drilled Shafts and Augered, Cast-in-Place Piles 796.3 Modification of Shaft Head for High-Strain Tests 846.4 Practical Considerations for Drop-Weight Techniques 876.5 HSDT Alternatives 896.6 Limitations of High-Strain Dynamic Testing 987 LOW-STRAIN SURFACE TESTS – SONIC ECHO 1017.1 Sonic Echo (Impulse ECHO) 1028 SONIC MOBILITY (IMPULSE RESPONSE) 1158.1 Principles of Impulse–Response Curve Interpretation 1228.2 Practical Considerations 1248.3 Classification of Signal Responses 1278.4 Pile Simulation Techniques 1328.5 Time Domain–Velocity Reflectors 1359 THE IMPEDANCE-LOG ANALYSIS 13710 LOW-STRAIN DOWN-HOLE TESTS 14310.1 Introduction 14310.2 Cross-Hole Sonic Logging 14310.3 Cross-Hole Tomography 14810.4 Single-Hole Sonic Logging 15210.5 Gamma–Gamma Logging 15510.6 Parallel Seismic Testing 16211 FIELD MOCK-UPS OF DEEP FOUNDTIONS: CLASS-A PREDICTIONS 16712 THE RELIABILITY OF PILE SHAFT INTEGRITY TESTING 17512.1 Statistical NDT Sampling Schemes 17612.2 Methodology Reliability 17813 CURRENT RESEARCH 18913.1 Developments in Measurement and Analysis 19013.2 Electrical Methods 19013.3 Optical Techniques 19813.4 Guided Wave Analysis 20113.5 Statistical Analysis 20213.6 Self-Consolidating Concrete 20313.7 Acceptable Vibration Levels 20613.8 Automated Monitoring Systems 20613.9 Wireless Acquisition Systems 20713.10 'SMART' Structures 20814 THE PLACE OF NONDESTRUCTIVE TESTING AT THE BEGINNING OF THE 21ST CENTURY 21114.1 Nondestructive testing and load and resistance factor design 21414.2 Setting up an Effective Quality Management Program 21514.3 Who's Testing the Tester? 21614.4 Acceptance Criteria 22014.5 Evaluating Defects 221APPENDIX I STRESS-WAVE PROPAGATION IN CYLINDRICAL STRUCTURES 2231. General Theory 2232. Determination of Damping 2283. Determination of Harmonic Response – Mechanical Impedance 2294. Resonant frequency of an infinitely long pile 2325. Impedance input for a finite length pile with unknown mechanical impedance at its base 233APPENDIX II CONTACT ADDRESSES 235APPENDIX III STANDARDS REFERRED TO IN THIS BOOK 2391. Cross–Hole Sonic Logging 2392. GAMMA–GAMMA Logging 2403. High-Strain Testing of Piles 2404. Impulse-echo and Impulse-Response Tests 2405. Parallel Seismic 2416. Static Load Testing of Deep Foundation Shafts 241APPENDIX IV SAMPLE SPECIFICATIONS FOR NDT METHODS FOR DEEP FOUNDATIONS 2431. Sample Specification for Low-Strain Testing by Either Impulse Echo or Impulse Response 2442. Sample Specification for Cross-Hole Sonic Logging (CSL) 248REFERENCES 255INDEX 267