Title Page
ABSTRACT
국문 초록
Contents
NOMENCLATURE 21
CHAPTER 1. INTRODUCTION 24
CHAPTER 2. BACKGROUND & OBJECTIVES 26
2.1. Design specifications 26
2.1.1. ASCE 10-15 (Design of Latticed Steel Transmission Structures) 26
2.1.2. ASCE 74 (Guidelines for Electrical Transmission Line Structural Loading) 27
2.1.3. NESC (National Electrical Safety Code) 29
2.1.4. IEC 60826 (Design Criteria of Overhead Transmission Lines) 30
2.1.5. DS-1111 31
2.1.6. Summary 33
2.2. Literature reviews 35
2.2.1. State of art for research of optimization in the transmission towers 35
2.2.2. Summary 46
2.3. Research objectives and scope 48
CHAPTER 3. INVESTIGATION OF DESIGN STRATEGY IN TRANSMISSION TOWERS 50
3.1. Conventional design practice for transmission towers 50
3.2. Observation for optimization of design and geometric configuration 52
CHAPTER 4. STRUCTURAL ANALYSIS 56
4.1. Model descriptions 56
4.1.1. 154kV-class transmission tower 58
4.1.2. 345kV-class transmission tower 61
4.1.3. 765kV-class transmission tower 64
4.2. Examined load combinations 67
4.3. Analysis methodologies 76
4.3.1. Linear static analysis 76
4.3.2. Eigenvalue analysis 77
4.3.3. Geometric nonlinear and inelastic analysis 78
CHAPTER 5. OPTIMIZATION IN DESIGN FOR SLIMING THE GEOMETRIC CONFIGURATION 79
5.1. Evaluation standard of optimization of the geometric configuration 81
5.2. Investigation of dominant load condition 85
5.3. Analytical variables for the slope of the main post 89
5.4. Analyzation of parametric studies 92
5.5. Model replaced with circular hollow sections 97
5.5.1. 154kV-class transmission tower 98
5.5.2. 345kV-class transmission tower 103
5.5.3. 765kV-class transmission tower 114
5.6. Implication of optimization in the geometric configuration 121
CHAPTER 6. OPTIMIZATION OF DEISN IN TERMS OF STRENGTH ENHANCEMENT 123
6.1. Effect of distortional resistance 124
6.1.1. 154kV-class transmission tower 125
6.1.2. 345kV-class transmission tower 133
6.1.3. 765kV-class transmission tower 140
6.1.4. Summary 144
6.2. Enhancement effect of elastic buckling strength 147
6.2.1. 154kV-class transmission tower 149
6.2.2. 345kV-class transmission tower 155
6.2.3. 765kV-class transmission tower 159
6.2.4. Summary 163
6.3. Contribution of horizontal members enhancing load-carrying capacity 166
6.3.1. 154kV-class transmission tower 166
6.3.2. 345kV-class transmission tower 172
6.3.3. 765kV-class transmission tower 179
6.3.4. Summary 183
6.4. Implication of optimized design for strength enhancement 189
CHAPTER 7. CONCLUSION 191
REFERENCES 194
Table 1. Summary of analytical methodologies for investigating the influence of the horizontal members 54
Table 2. Section properties of 154kV-class 59
Table 3. Details of the conductors and overhead ground wires in the 154kV-class 60
Table 4. Section properties of 345kV-class 62
Table 5. Details of the conductors and overhead ground wires in the 345kV-class 63
Table 6. Section properties of 765kV-class 65
Table 7. Details of the conductors and overhead ground wires in the 765kV-class 66
Table 8. Reference speed pressure by terrain influence (DS-111) 68
Table 9. Standard equivalent wind pressure of the tower (L-angle) (DS-1111) 70
Table 10. Standard equivalent wind pressure of the tower (circular pipe) (DS-1111) 71
Table 11. Standard equivalent wind pressure of wires (DS-1111) 72
Table 12. Standard equivalent wind pressure of insulator (DS-1111) 72
Table 13. Standard equivalent wind pressure of cross-arm (DS-1111) 73
Table 14. Application of standard equivalent wind pressure applied to the transmission tower 74
Table 15. Dimensions by variables in Case I 91
Table 16. Dimensions by variables in Case II 91
Table 17. Comparison of appropriate models by variable (765kV-class) 94
Table 18. Comparison of reduction rate in footprint and weight (154kV-class) 101
Table 19. Comparison of models with a diameter of 406.4 mm (345kV-class) 106
Table 20. Comparison of models with a diameter of 457.2 mm (345kV-class) 108
Table 21. Comparison of models with a diameter of 500.0 mm (345kV-class) 110
Table 22. Comparison of models with a diameter of 508.0 mm (345kV-class) 111
Table 23. Comparison of models with a diameter of 558.8 mm (345kV-class) 112
Table 24. Comparison of reduction rate in footprint and weight (345kV-class) 113
Table 25. Comparison of models with a diameter of 508.0 mm (765kV-class) 116
Table 26. Comparison of models with a diameter of 558.8 mm (765kV-class) 118
Table 27. Comparison of models with a diameter of 600.0 mm (765kV-class) 119
Table 28. Comparison of footprint and weight reduction rate (765kV-class) 120
Table 29. Displacement of points in the main posts by torsional loads (154kV-class) 130
Table 30. Displacement of points in the braces by torsional loads (154kV-class) 131
Table 31. Displacement of points in the main posts by torsional loads (345kV-class) 137
Table 32. Displacement of points in the braces by torsional loads (345kV-class) 138
Table 33. Displacement of points in the main posts by torsional loads (765kV-class) 142
Table 34. Displacement of points in the braces by torsional loads (765kV-class) 142
Table 35. Details of slenderness ratio (154kV-class) 147
Table 36. Details of slenderness ratio (345kV-class) 148
Table 37. Details of slenderness ratio (765kV-class) 148
Table 38. Comparison of elastic buckling strength by the effect of horizontal members (154kV-class) 154
Table 39. Comparison of elastic buckling strength by the effect of horizontal members (345kV-class) 159
Table 40. Comparison of elastic buckling strength by the effect of horizontal members (765kV-class) 162
Table 41. Comparison of load-carrying capacity by the effect of horizontal members (154kV-class) 169
Table 42. Comparison of load-carrying capacity by the effect of horizontal members (345kV-class) 172
Table 43. Comparison of load-carrying capacity by the effect of horizontal members (765kV-class) 181
Table 44. Appropriate number of horizontal members for strength enhancement 190
Figure 1. Description of diaphragm locations (ASCE 10-15) 27
Figure 2. Standardized design condition of transmission tower (DS-1111) 31
Figure 3. Conventional design process of transmission towers 51
Figure 4. Social issues related to transmission towers (Technical Report by KEPRI) 52
Figure 5. Functional role of horizontal members 54
Figure 6. Overview of variables 55
Figure 7. Description of section members 57
Figure 8. Description of boundary condition 57
Figure 9. Characteristics and dimensions of 154kV-class 58
Figure 10. Details of 154kV-class analytical model 60
Figure 11. Characteristics and dimensions of 345kV-class 61
Figure 12. Details of 345kV-class analytical model 63
Figure 13. Characteristics and dimensions of 765kV-class 64
Figure 14. Details of 765kV-class analytical model 66
Figure 15. Description of load direction in the transmission tower (ASCE 74) 68
Figure 16. Analytical model applied in the design load combinations. 75
Figure 17. Description of an L-angle section subjected to biaxial bending 83
Figure 18. Comparison of FEM and manual calculation 84
Figure 19. Definition of main post's location 85
Figure 20. Investigation of dominant load conditions 87
Figure 21. Parametric variables of the slope of the main post 90
Figure 22. Description of the panel in each capacity 92
Figure 23. Investigation of stress ratio in each capacity 93
Figure 24. Investigation of the optimizing the geometric configuration in 765kV-class 96
Figure 25. Description of model replaced by circular pipe (154kV-class) 98
Figure 26. Description of the failed member in parametric models 99
Figure 27. Comparison of stress ratio in the parametric model (154kV-class) 100
Figure 28. Evaluation of parametric model (154kV-class) 101
Figure 29. Description of model replaced by circular pipe (345kV-class) 103
Figure 30. Description of the panel in model replaced by circular pipe (345kV-class) 104
Figure 31. Comparison of models with a diameter of 406.4 mm (345kV-class) 105
Figure 32. Comparison of models with a diameter of 457.2 mm (345kV-class) 107
Figure 33. Details of limitation in Case I (345kV-class) 108
Figure 34. Comparison of models with a diameter of 500.0 mm (345kV-class) 109
Figure 35. Comparison of models with a diameter of 508.0 mm (345kV-class) 110
Figure 36. Comparison of models with a diameter of 558.8 mm (345kV-class) 111
Figure 37. Details of limitation of Case II (345kV-class) 112
Figure 38. Evaluation of parametric model (345kV-class) 113
Figure 39. Description of variables (765kV-class) 114
Figure 40. Comparison of models with a diameter of 508.0 mm (765kV-class) 115
Figure 41. Comparison of models with a diameter of 558.8 mm (765kV-class) 117
Figure 42. Comparison of models with a diameter of 600.0 mm (765kV-class) 118
Figure 43. Evaluation of parametric model (765kV-class) 120
Figure 44. Position and plane of horizontal members 124
Figure 45. Comparison of deformed shape under the examined load combination (154kV-class) (Scale factor: 10.0) 126
Figure 46. Comparison of distortional resistance effect with or without horizontal members (154kV-class) (Scale factor: 1.0) 127
Figure 47. Comparison of distortional resistance effect with parametric variables (154kV-class) (Scale factor: 3.0) 129
Figure 48. Comparison of deformed shape under the examined load combination (345kV-class) (Scale factor: 10.0) 134
Figure 49. Comparison of distortional resistance effect with or without horizontal members (345kV-class) (Scale factor: 1.0) 135
Figure 50. Comparison of distortional resistance effect with parametric variables (345kV-class) (Scale factor: 3.0) 136
Figure 51. Comparison of deformed shape under the examined load combination (765kV-class) (Scale factor: 10.0) 140
Figure 52. Comparison of distortional resistance effect with or without horizontal members (765kV-class) (Scale factor: 3.0) 141
Figure 53. Comparison of the distortion resistance contributed by the effect of horizontal members (Scale factor: 3.0) 145
Figure 54. Proper models contributed by distortional resistance effect of horizontal members 146
Figure 55. Details of variables in the 154kV-class analytical model 149
Figure 56. Comparison of elastic buckling strength and corresponding modes contributed by the number and position of horizontal members (154kV-class) 151
Figure 57. Investigation of elastic buckling strength and corresponding modes (154kV-class) 153
Figure 58. Elastic buckling strength and Corresponding mode in the low-order mode through parametric analysis (345kV-class) 155
Figure 59. Investigation of elastic buckling strength and corresponding modes (345kV-class) 158
Figure 60. Investigation of elastic buckling strength and corresponding modes (765kV-class) 161
Figure 61. Comparison of enhancing of elastic buckling strength by effect of horizontal members 164
Figure 62. Proper positions contributed by horizontal members to enhance elastic buckling strength 165
Figure 63. Progress of deformation contributed by the effect of horizontal members (154kV-class) (scale factor: 5.0) 169
Figure 64. Comparison of load-displacement curves contributed by horizontal members (154kV-class) 171
Figure 65. Progress of deformation contributed by the effect of horizontal members (345kV-class) (scale factor: 5.0) 175
Figure 66. Comparison of failed members by effect of horizontal members (345kV-class) 175
Figure 67. Comparison of load-displacement curves contributed by horizontal members (345kV-class) 177
Figure 68. Comparison of moment flow at the vulnerable point in the models with two and three horizontal members 178
Figure 69. Progress of deformation contributed by the effect of horizontal members (765kV-class) (scale factor: 5.0) 181
Figure 70. Comparison of failed members by effect of horizontal members (765kV-class) (scale factor: 10.0) 182
Figure 71. Comparison of the contribution by the horizontal members enhancing load-carrying capacity (Scale factor: 5.0) 184
Figure 72. Comparison of stress flow according to the effect of horizontal members (Scale factor: 10.0) 186
Figure 73. Additional comparison of stress flow in the 765kV-class model (Scale factor: 10.0) 187
Figure 74. Proper models contributed by the effect of horizontal members enhancing load-carrying capacity. 188
Figure 75. Proper position of horizontal members for strength enhancement 190