Innovative AE and NDT Techniques for On-Site Measurement of Concrete and Masonry Structures (eBook)

RILEM Publications 6
Contents 14
1 Introduction 15
Abstract 15
2 Concrete Structures 19
Abstract 19
2.1 Introduction 20
2.2 Material and Structural Conditions for Measurements 20
2.3 Requirements by the Stakeholders 21
2.4 New Developments on Devices 22
2.4.1 Improvement of Devices and Sensors 22
2.4.2 Calibration of Equipment and Transfer Functions of Transducers 23
2.4.3 Coupling of Transducers 25
2.5 Data Processing Techniques 27
2.5.1 Examples of Present Applications 27
2.5.2 Automation and Combination of Techniques 28
2.6 Improvement of Data Processing Techniques 29
2.6.1 New Inversion Techniques for Ultrasound 30
2.6.2 Reliability Analysis for NDT Methods and the Effect of a Defect 31
2.7 Numerical Simulation and Forward Modeling 32
2.8 Temporal and Spatial Evaluation of PC Cable Breakage 35
2.9 Concluding Remarks 36
References 36
3 Masonry Structures 40
Abstract 40
3.1 Introduction 40
3.2 AE Monitoring of Historical Buildings and Monuments 41
3.3 The Medieval Towers of Alba 42
3.4 The Cathedral of Syracuse 43
3.5 The Monte Tabor Chapel in Varallo 48
3.5.1 Scaling Laws for AE Monitoring 49
3.5.2 b-Value Analysis for AE Monitoring 50
3.5.3 Monitoring Results 52
3.6 Conclusions 56
Acknowledgments 56
References 56
4 Computerized AE Tomography 60
Abstract 60
4.1 Introduction 60
4.2 Computational Flow of AE Tomography 61
4.3 Source Location Technique 62
4.4 Elastic-Wave Tomography with Estimation of Source Location 63
4.5 Numerical Verification of Two-Dimensional AE Tomography 66
4.5.1 Source Location Technique in Two-Dimensional Problem 66
4.5.2 AE Tomography in Two-Dimensional Problem 68
4.6 Numerical Examples of Three-Dimensional AE Tomography 69
4.6.1 Source Location Technique in Three-Dimensional Problem 69
4.6.2 AE Tomography in Three-Dimensional (3D) Problem 71
4.7 Applications 73
4.7.1 Planar Structure 73
4.7.2 Cylindrical Specimens 78
4.8 Concluding Remarks 80
References 81
5 Acoustic Emission Analysis for NDE in Concrete 82
Abstract 82
5.1 Introduction 82
5.2 Analysis Based on the Total Activity 84
5.3 AE Parameter Analysis 86
5.3.1 Relation of AE Waveform to Fracture Process 86
5.4 AE Waveform Parameter Analysis 88
5.5 Combination of NDT Techniques 95
5.6 Conclusions 96
References 97
6 Cross-Sectional Visualization of Defects by SIBIE 102
Abstract 102
6.1 Introduction 102
6.2 Impact-Echo and Key Issues Associated 103
6.3 Development of Impactors 105
6.3.1 Impactors 105
6.3.2 Impact Test 106
6.3.3 Theory for Analysis 107
6.3.4 Evaluation of Impactor Response 108
6.4 Selection of the Sensor 109
6.5 SIBIE Procedure 110
6.6 On-site Applications 111
6.6.1 Imperfectly Grouted Sheath in Prestressed Concrete 111
6.6.2 Depth of Surface Crack 113
6.7 Concluding Remarks 115
References 115
7 3D Visualization of Crack Kinematics by AE-SiGMA 117
Abstract 117
7.1 Introduction 117
7.2 Theoretical Background and Principle 118
7.3 Simplified Procedure 119
7.4 First-Motion Detection 121
7.5 Implementation of SiGMA Code 123
7.6 Visualization of SiGMA Results 125
7.7 Concluding Remarks 127
Appendix: Sample Program of SiGMA 128
References 143
8 Hybrid NDE for Rebar Corrosion in Concrete 144
Abstract 144
8.1 Introduction 145
8.2 Phenomenological Model of Corrosion Process and AE Observation 146
8.2.1 The Model of Corrosion Process 146
8.2.2 Accelerated Corrosion Experiments 147
8.2.3 AE Observation 148
8.2.4 Visual Confirmation 151
8.3 Mechanisms of Corrosion-Induced Cracks 152
8.3.1 Cyclic Wet-Dray Tests 152
8.3.2 Numerical Analysis 153
8.3.3 AE Activity and Half-Cell Potential 154
8.3.4 Numerical Analysis by FEM and BEM 154
8.3.5 SiGMA Analysis and Visual Observation 155
8.4 Electro-Chemical Measurement and PiBEM Analysis 156
8.4.1 PiBEM Analysis 157
8.4.2 Experiments for Hybrid NDE 158
8.4.3 AE Activities 159
8.4.4 Potential Analysis 159
8.4.5 Confirmation by Micrograph Observation 160
8.5 Concluding Remarks 161
Appendix: Program for PiBEM Aanalysis 162
References 166
9 On-Site Damage Evaluation by AE and CT in Concrete 167
Abstract 167
9.1 Introduction 167
9.2 Crack Evolution in Concrete Structures In-Service 168
9.2.1 Concrete Damage in Damage Mechanics 168
9.2.2 Visualization and Quantification of Cracks in Concrete Using X-ray CT 169
9.3 Evaluation of Mechanical Properties in Cracked Concrete by AE 172
9.3.1 Characteristics of AE Generation Behavior in Core Test 172
9.4 On-site Damage Evaluation Using DeCAT 172
9.4.1 DeCAT Procedure 172
9.4.2 Damage Estimation of Concrete by DeCAT and Dynamic Modulus of Elasticity Ed 176
9.4.3 Case Study: Damage Evaluation of RC Arch Member in Service for 87 Years 177
9.4.4 Case Study: Concrete Canal Structure Affected by Earthquake 178
9.5 Conclusion 180
References 181
10 Overview of Visualized NDE for On-Site Measurement 182
Abstract 182
10.1 Introduction 182
10.2 Overview and Achievements 183
10.3 Concluding Remarks 185