Title Page
Contents
ABSTRACT 16
국문초록 19
CHAPTER 1. INTRODUCTION 22
1.1. Research background 22
1.2. Research significance and objectives 24
1.3. Organization of the thesis 25
CHAPTER 2. LITERATURE REVIEW 27
2.1. Overview of previous test results for masonry walls 27
2.2. Structural behaviors of unreinforced masonry walls 36
2.3. Seismic retrofit methods of unreinforced masonry walls 49
2.4. Structural behaviors of retrofitted masonry walls 53
CHAPTER 3. DEVELOPMENT OF RETROFIT TECHNOLOGY FOR MASONRY WALLS 58
3.1. Prototype masonry building to quantify retrofit demand 59
3.2. FRCC precast panel technology 67
3.2.1. FRCC mix proportion 68
3.2.2. Material characteristics of FRCC 71
3.2.3. Direct shear test on FRCC materials 75
3.2.4. Z-type push off test on FRCC panel connections 92
3.2.5. Design method using FRCC precast panel technology 112
3.3. FRCC cast-in-place technology 115
3.3.1. Material characteristics of FRCC system 115
3.3.2. Design method using FRCC cast-in-place technology 115
3.4. TRM cast-in-place technology 117
3.4.1. Material characteristics of TRM composites 117
3.4.2. Design method using TRM cast-in-place technology 118
3.5. GFRP cast-in-place technology 120
3.5.1. Material characteristics of GFRP strips 120
3.5.2. Design method using GFRP cast-in-place technology 121
3.6. Application process of developed retrofit technology 123
CHAPTER 4. EXPERIMENTAL INVESTIGATING SEISMIC PERFORMAND OF MASONRY WALLS WITH OR WITHOUT RETROFIT 127
4.1. Experimental program 127
4.1.1. Materials 127
4.1.2. Design of the test specimens 129
4.1.3. Details and parameters of test specimens 132
4.1.4. Test setup, loading protocol and measuring instruments 138
4.2. Cyclic loading test results and discussion 143
4.2.1. Crack characteristics 143
4.2.2. Load-drift responses 150
4.2.3. Nonlinear characteristics based on bilinear backbone curves 158
4.2.4. Stiffness degradation 162
4.2.5. Energy dissipation capacity 164
CHAPTER 5. NONLINEAR MODELING FOR RETROFITTED MASONRY WALLS USING DEVELOPED TECHNOLOGY 170
5.1. Development of strength evaluation model 170
5.2. Investigation of nonlinear modeling parameters 181
5.3. Model verification 186
5.4. Application of nonlinear modeling methods 191
CHAPTER 6. CONCLUSIONS 198
6.1. Summary 198
6.2. Conclusions 199
(1) Development of various practical retrofit technologies 199
(2) Direct shear test results of FRCC materials 200
(3) Push-off test results of FRCC precast panel connections 201
(4) Structural test results of masonry walls retrofitted by FRCC precast and cast-in-place methods 202
(5) Theoretical approach to predict the idealized backbone curves of masonry walls retrofitted by FRCC precast and cast-in-place methods 203
6.3. Expected applications and further investigations 203
REFERENCES 205
APPENDICIES 225
APPENDIX A. NONLINEAR ANALYSIS MODEL FOR UNREINFORCED MASONRY WALLS BASED ON FRAGILITY ANALYSIS 226
A.1. Comparison with current nonlinear modeling methods of unreinforced masonry walls 226
A.2. Fragility analysis for unreinforced masonry walls 230
A.3. Model development and verification 236
APPENDIX B. DATABASE OF PREVIOUS STUDIES 244
APPENDIX C. RESEARCH ACHIEVEMENT BY THE AUTHOR 250
[Table 2-1] Nonlinear modeling parameters for URM in-plane walls 44
[Table 3-1] Comparison of shear demands and capacities of URM in-plane walls in X direction of prototype masonry system 64
[Table 3-2] Comparison of shear demands and capacities of URM in-plane walls in Y direction of prototype masonry system 65
[Table 3-3] Material properties of steel and nylon fibers used in this study 69
[Table 3-4] Mix proportion of fiber reinforced cementitious composite 70
[Table 3-5] Compressive strength of test specimens 73
[Table 3-6] Tensile strength of test specimens 74
[Table 3-7] Shear test results in the pre-peak stage 80
[Table 3-8] Shear test results in the post-peak stage 81
[Table 3-9] Mortar mix proportion used for shear keys of the panel connections 93
[Table 3-10] Compressive test results of mortar mixtures 93
[Table 3-11] Details of push-off test specimens 95
[Table 3-12] Summary of push-off test results 102
[Table 3-13] Characteristics of carbon fiber textile used in this study 118
[Table 3-14] Mechanical characteristics of glass fiber reinforced polymers 121
[Table 4-1] Designed lateral strengths of URM-CS specimen 131
[Table 4-2] Main test parameters and details of the test specimens 132
[Table 4-3] Summary of test results 143
[Table 4-4] Performance indices obtained from idealized backbone curves 160
[Table 5-1] Nonlinear modeling parameters for retrofitted masonry walls in ASCE/SEI 41-17 183
[Table 5-2] Comparison between experimental and estimated lateral strengths 187
[Table 5-3] Comparison of shear demands and capacities of masonry in-plane walls in 1st floor of prototype masonry system before and after system retrofitting[이미지참조] 193
[Table 5-4] Comparison of shear demands and capacities of masonry in-plane walls in 1st floor of prototype masonry system before and after member retrofitting...[이미지참조] 194
[Table 5-5] Comparison of shear demands and capacities of masonry in-plane walls in 1st floor of prototype masonry system before and after member retrofitting[...이미지참조] 195
[Table A-1] Proposed nonlinear modeling parameters for URM in-plane walls 238
[Figure 1-1] Collapse of masonry buildings after Gyeong-ju and Po-hang earthquakes occurred 23
[Figure 2-1] Structural test setup for masonry walls in previous studies 28
[Figure 2-2] Strength distribution levels in accordance with key variables 29
[Figure 2-3] Distribution levels of drift ratio corresponding to peak strength at cantilever boundary conditions in accordance with key variables 32
[Figure 2-4] Distribution levels of ultimate drift ratio at cantilever boundary conditions in accordance with key variables 33
[Figure 2-5] Distribution levels of drift ratio corresponding to peak strength at fixed ends boundary conditions in accordance with key variables 34
[Figure 2-6] Distribution levels of ultimate drift ratio at fixed ends boundary conditions in accordance with key variables 35
[Figure 2-7] Typical failure modes of masonry walls 37
[Figure 2-8] The pictures of brittle failure of masonry 39
[Figure 2-9] Deformation relationships of URM walls 44
[Figure 2-10] Computational strategies for masonry modeling 47
[Figure 2-11] Various seismic retrofit method of URM walls 50
[Figure 2-12] Various application of FRCC materials in construction fields 51
[Figure 2-13] Different types of fibers utilized for FRCC 53
[Figure 2-14] Sem observation of the FRCC composites 53
[Figure 2-15] Application of FRCC for URM walls 55
[Figure 3-1] Floor plan of prototype masonry system 60
[Figure 3-2] Elevation of prototype masonry system 61
[Figure 3-3] Schematic of L-shaped precast FRCC panel details 67
[Figure 3-4] Microscope photos of steel and nylon fibers 69
[Figure 3-5] Test setups for mortar flow, air content, compressive, and tensile strength tests 71
[Figure 3-6] Details of test specimen and schematic of test setup 76
[Figure 3-7] Representative crack patterns of test specimens 79
[Figure 3-8] Shear stress-crack slip and crack width curves of the NM specimens 83
[Figure 3-9] Shear stress-crack slip and crack width curves in N series 84
[Figure 3-10] Shear stress-crack slip and crack width curves in S series 85
[Figure 3-11] Shear stress-crack slip and crack width curves in S-N series 86
[Figure 3-12] Crack slip and crack width at failure versus incorporated fiber volume fraction in N and S series 88
[Figure 3-13] Effect of nylon and steel fiber volume fractions on the shear stress of the test specimens in N and S series 91
[Figure 3-14] Representative tensile stress-strain relationships for reinforcing bars 94
[Figure 3-15] Details of push-off test specimens 96
[Figure 3-16] Representative manufacturing process of the 100-H specimen 99
[Figure 3-17] Direct push-off test setup and measuring instruments 100
[Figure 3-18] Crack patterns and failure modes of test specimens 103
[Figure 3-19] The shear load-vertical displacement curves in V series 106
[Figure 3-20] The shear load-vertical displacement curves in D series 107
[Figure 3-21] The shear load-vertical displacement curves in C series 110
[Figure 3-22] Re-bar strain in shear keys of specimens in V-S0.75 112
[Figure 3-23] Retrofitting procedure of FRCC precast panel technology 114
[Figure 3-24] Retrofitting procedure of cast-in-place technology using FRCC 116
[Figure 3-25] Characteristics of carbon fiber mesh 118
[Figure 3-26] Retrofitting procedure of cast-in-place technology using TRM composites 119
[Figure 3-27] Retrofitting procedure of cast-in-place technology using GFRP 122
[Figure 3-28] Application examples of developed retrofit technology 124
[Figure 4-1] Masonry material tests 128
[Figure 4-2] Details of control specimen URM-CS 130
[Figure 4-3] Details of retrofitted specimens using precast method 135
[Figure 4-4] Details of retrofitted specimens using cast-in-place methods 137
[Figure 4-5] Lateral cyclic test setup of masonry specimens 140
[Figure 4-6] Layout of measuring instruments 141
[Figure 4-7] Loading protocol of lateral cyclic test 142
[Figure 4-8] Observed crack patterns and failure mode 144
[Figure 4-9] Hysteresis load-drift ratio curves in S1 series 152
[Figure 4-10] Hysteresis load-drift ratio curves in S2 series 154
[Figure 4-11] Hysteresis load-drift ratio curves in CIP series 155
[Figure 4-12] Load-drift ratio envelope curves 156
[Figure 4-13] Bilinear backbone curves in accordance with ASTM E2126 159
[Figure 4-14] Stiffness deterioration 163
[Figure 4-15] Energy dissipation capacity 166
[Figure 4-16] Equivalent viscous damping ratio 168
[Figure 5-1] Analytical model of multiaxial compression for masonry 172
[Figure 5-2] Idealized backbone model for retrofitted masonry specimens 181
[Figure 5-3] Comparison between test results and predictions by the proposed model for all test specimens 189
[Figure 5-4] Comparison between nonlinear modeling results of masonry walls with or without retrofit by using developed technologies 197
[Figure A-1] The ratio between ultimate drift from previous test results and current design code 229
[Figure A-2] Fragility curves of previous test results based on three limit state 231
[Figure A-3] Fragility curves of previous test results failed in rocking & toe crushing based on various parameters 233
[Figure A-4] Fragility curves of previous test results failed in diagonal tension based on various parameters 234
[Figure A-5] Fragility curves for ratio between ultimate drift ratio from previous test results and current design code 235
[Figure A-6] Proposed idealized backbone curve based on ASCE/SEI 41-17 238
[Figure A-7] The standard normal distribution of the major influential variables 241
[Figure A-8] Fragility curves for ratio between ultimate drift ratio from previous test results and proposed model 242