Optimum Design of Steel Structures
اسم المؤلف
Jozsef Farkas and Karoly Jarmai
التاريخ
المشاهدات
496
التقييم
(لا توجد تقييمات)
Loading...
التحميل

Optimum Design of Steel Structures
Jozsef Farkas and Karoly Jarmai
Contents
Preface . V
Acknowledgements IX
About the Authors . XIX
List of Symbols . XXI
Abbreviations .. XXV
1 Experiences with the Optimum Design of Steel Structures .. 1
1.1 Introduction 1
1.2 Foundation of the School for Structural Optimization
at the University of Miskolc . 2
1.3 Derivation of the Structural Optimization System .. 2
1.4 Advantages and Disadvantages of Two Different Design Methods .. 5
1.4.1 Design by Routine . 5
1.4.2 Optimum Design 6
1.5 The Problem of the Interaction of Two Instabilities .. 6
1.6 Detailed Results for Different Structural Types 7
1.6.1 Compressed and Bent Columns Constructed from Stiffened
Shell or from Square Box Walls of Stiffened Plates 7
1.6.2 Stiffened or Cellular Plate Supported at Four Corners
Subject to a Uniformly Distributed Normal Load (Fig.1.4) . 9
1.6.3 A Wind Turbine Tower Constructed as a Shell or Tubular
Truss Structure 9
1.7 Survey of Selected Literature of the Optimum Design of Steel
Structures .. 11
1.7.1 Truss Structures 11
1.7.2 Building Frames .. 11
1.7.3 Industrial Applications . 11
1.8 Conclusions . 13
2 Newer Mathematical Methods in Structural Optimization 15
2.1 Introduction . 15
2.2 Firefly Algorithm .. 16
2.3 Particle Swarm Optimization Algorithm .. 19
2.3.1 The PSO Algorithm 19
2.3.2 Modification of PSO Algorithm with Gradient Estimation 21
2.3.3 Comparing the Standard PSO and the Modified PSO (GPSO) 23
2.4 The IOSO Technique .. 24XII Contents
2.4.1 Main Features of IOSO Technology . 24
2.4.2 Testing of the Method .. 25
2.4.3 Novelty and Distinctive Features of IOSO . 27
3 Cost Calculations .. 29
3.1 Introduction .29
3.2 The Cost Function .29
3.2.1 The Cost of Materials ..30
3.2.2 The Fabrication Cost in General 30
3.2.2.1 Fabrication Times for Welding ..30
3.2.2.2 Thermal and Waterjet Cutting .32
3.2.2.3 Time for Flattening Plates .39
3.2.2.4 Surface Preparation Time ..39
3.2.2.5 Painting Time ..40
3.2.2.6 Times of Hand Cutting and Machine Grinding
of Strut Ends .40
3.2.2.7 Cost of Intumescent Painting ..40
3.2.3 Total Cost Function ..40
3.3 Conclusion 41
4 Beams and Columns 43
4.1 Comparison of Minimum Volume and Minimum Cost Design
of a Welded Box Beam .. 43
4.1.1 Introduction 43
4.1.2 Minimum Cross-Sectional Area Design . 44
4.1.3 Minimum Cost Design . 46
4.1.4 Numerical Data and Results . 46
4.2 Minimum Cost Design for Fire Resistance of a Welded Box Column
and a Welded Box Beam 47
4.2.1 Introduction 47
4.2.2 The Critical Temperature Method . 48
4.2.3 A Centrally Compressed Column with Pinned Ends of Welded
Square Box Cross-Section 50
4.2.3.1 Overall Buckling Constraint for Ambient
Temperature 51
4.2.3.2 Overall Buckling Constraint in Fire .. 51
4.2.3.3 Local Buckling Constraint .. 52
4.2.3.4 Cost Function . 52
4.2.3.5 Numerical Data and Results .. 53
4.2.3.6 Cost Including Protection 53
4.2.4 A Simply Supported Uniformly Loaded Welded Box Beam 54
4.2.4.1 Optimum Design . 54
4.2.4.2 Optimum Design of Unprotected Beam with Stress
Constraint 55
4.2.4.3 Optimum Design of the Protected Beam with Stress
Constraint 57Contents XIII
4.2.4.4 Optimum Design of Unprotected Beam with Deflection
Constraint 57
4.2.4.5 Optimum Design of the Protected Beam with Deflection
Constraint 58
4.2.5 Conclusions 58
5 Tubular Trusses . 61
5.1 Survey of Selected Literature .. 62
5.2 Comparison of Minimum Volume and Minimum Cost Design
of a Welded Tubular Truss .. 63
5.2.1 Introduction 63
5.2.2 Minimum Volume Design . 63
5.2.3 Minimum Cost Design . 66
5.2.4 Numerical Data and Results . 67
5.2.5 Conclusions 68
5.3 Optimum Design of Tubular Trusses for Displacement Constraint . 68
5.3.1 Introduction 69
5.3.2 The Displacement Constraint 69
5.3.3 Design for Overall Buckling . 69
5.3.4 A Truss Column with Parallel Chords (Fig. 5.2) 70
5.3.5 A Truss Column with Non-parallel Chords (Fig. 5.3) . 72
5.4 Volume and Cost Minimization of a Tubular Truss with Non-parallel
Chords in the Case of a Displacement-Constraint .. 75
5.4.1 Introduction 75
5.4.2 Minimum Volume Design of the Tubular Truss
with Non-parallel Chords .. 76
5.4.3 Check of the Compression Rods for Overall Buckling 80
5.4.4 The Cost Function .. 80
5.4.5 Numerical Data 82
5.4.6 The Optimization Process .. 82
5.4.7 Results of the Optimization .. 82
5.4.8 Check of Strength of a Tubular Joint 83
5.4.9 Conclusions 85
5.5 Minimum Cost Design and Comparison of Tubular Trusses
with N- and Cross-(Rhombic)-Bracing . 86
5.5.1 Introduction 86
5.5.2 The Optimization Process .. 87
5.5.3 Optimum Design of an N-Type Planar Tubular Truss . 88
5.5.3.1 Optimum Height and Cross-Sectional Areas
for Stress and Overall Buckling Constraints .. 88
5.5.3.2 Optimum Height and Cross-Sectional Areas
for Deflection Constraint . 90
5.5.4 Optimum Design of a Rhombic-Type Planar Tubular Truss 91
5.5.4.1 Optimum Height and Cross-Sectional Areas for Stress
and Overall Buckling Constraints 91XIV Contents
5.5.4.2 Check of a Truss Joint with Available Tubular
Profiles .. 94
5.5.4.3 Optimum Height and Cross-Sectional Areas
for Deflection Constraint 95
5.5.5 Comparison of the Two Bracing Types .. 97
5.5.6 Conclusions 97
5.6 Optimum Design of a Transmission Line Tower Constructed
from Welded Tubular Truss . 98
5.6.1 Introduction 98
5.6.2 Loads 99
5.6.3 Geometric Data (Fig. 5.10, 5.11) . 100
5.6.4 Rod Forces from a Horizontal Force F = 1 103
5.6.5 Rod Forces from H, F1 and F2 . 104
5.6.6 Optimization Process . 104
5.6.7 Formulae for Cross-Sectional Areas of Governing Rods . 104
5.6.8 Formulae for Volume V and Cost K of the Truss
in the Function of ? . 105
5.6.9 Search for ?opt for Vmin and Kmin .. 106
5.6.10 Selection of Available Profiles .. 107
5.6.11 Optimum Mass of the Tower .. 107
5.6.12 Mass Comparison with the Tower Published by Rao (1995) .. 107
6 Frames .. 109
6.1 Minimum Cost Seismic Design of a Welded Steel Portal Frame
with X-Bracing . 110
6.1.1 Absorbed Energy of CHS and SHS Braces Cyclically Loaded
in Tension-Compression .. 110
6.1.2 Seismic Design of a Portal Frame 116
6.1.2.1 Calculation of the Seismic Force .. 116
6.1.2.2 Normal Forces and Bending Moments in Vertical
Frames (Fig. 6.6) .. 118
6.1.2.3 Geometric Characteristics of the Square Hollow
Section (Fig. 6.7) .. 119
6.1.2.4 Calculation of the Elastic Sway . 120
6.1.2.5 Constraint on Sway Limitation .. 121
6.1.2.6 Local Buckling Constraints . 123
6.1.2.7 Stress Constraint for the Columns 123
6.1.2.8 Stress Constraint for the Beams . 124
6.1.2.9 Investigation of the Joint of the Beam and Brace . 125
6.1.2.10 The Cost Function 126
6.1.2.11 Optimization and Results . 127
6.1.2.12 Conclusions . 128
6.2 Seismic Design of a V-Braced 3D Multi-storey Steel Frame 129
6.2.1 Introduction . 129
6.2.2 Main Dimensions of the Given Frame .. 130
6.2.3 Loads . 131
6.2.3.1 Vertical Loads 131Contents XV
6.2.3.2 Seismic Load .. 131
6.2.4 Design of CHS V-Bracings . 132
6.2.4.1 Constraint on Tensile Stress 132
6.2.4.2 Constraint on Overall Buckling . 133
6.2.4.3 Constraint on Strut Slenderness for Seismic Zone .. 133
6.2.4.4 Constraint on Energy Absorption Capacity . 133
6.2.4.5 Design Results 134
6.2.5 Design of Beams .. 135
6.2.6 Design of Columns . 137
6.2.7 Design of Joints 139
6.2.7.1 Beam-to-Column Connections .. 139
6.2.7.2 Joints of Braces .. 140
6.2.8 Conclusions . 141
7 Stiffened Plates . 143
7.1 Minimum Cost Design of an Orthogonally Stiffened Welded Steel
Plate with a Deflection Constraint . 144
7.1.1 Introduction . 144
7.1.2 Residual Welding Deflection from Longitudinal Welds
of a Straight Beam . 145
7.1.3 Residual Welding Curvatures in an Orthogonally Stiffened
Plate 147
7.1.4 The Grid Effect . 148
7.1.5 Assembly Desk of Square Symmetry with 4-4 Stiffeners 150
7.1.5.1 Solution of the Gridwork from Shrinkage of Welds
(Fig. 7.4) 150
7.1.5.2 Solution of the Gridwork from the Uniformly
Distributed Normal Load (Fig. 7.5) . 152
7.1.6 Minimum Cost Design of the Assembly Desk with 4-4
Stiffeners Considering the Grid-Effect . 153
7.1.6.1 Stress Constraint 153
7.1.6.2 Deflection Constraint .. 154
7.1.6.3 Cost Function .. 155
7.1.6.4 Results of Optimization . 156
7.1.7 Minimum Cost Design of the Assembly Desk
without Grid Effect . 156
7.1.7.1 Stress Constraint 156
7.1.7.2 Deflection Constraint .. 157
7.1.7.3 Cost Function .. 158
7.1.7.4 Results of Optimization . 158
7.1.8 Conclusions . 159
7.2 Minimum Cost Design of a Welded Stiffened Steel Sectorial Plate . 159
7.2.1 Introduction . 160
7.2.2 Non-equidistant Tangential Stiffening .. 160
7.2.2.1 Calculation of Stiffener Distances (x0i) . 160
7.2.2.2 Design of Stiffeners . 162XVI Contents
7.2.2.3 Cost Calculation for a Sectorial Stiffened Plate
Element .. 164
7.2.3 Equidistant Tangential Stiffening with Stepwise Varying Base
Plate Thickness . 167
7.2.3.1 Design of Base Plate Thicknesses 167
7.2.3.2 Design of Stiffeners . 167
7.2.3.3 Cost Calculation 168
7.2.4 Equidistant Tangential Stiffening Combined with Radial
Stiffeners .. 170
7.2.5 Cost of the Unstiffened Plate . 172
7.2.6 Conclusions . 173
7.3 Optimum Design of Welded Stiffened Plate Structure for a Fixed
Storage Tank Roof . 174
7.3.1 Introduction . 174
7.3.2 Loads . 175
7.3.3 Numerical Data (Fig. 7.11) . 175
7.3.4 Design of Sectorial Stiffened Deck Plate Elements 176
7.3.4.1 Cost Calculation for a Sectorial Stiffened Plate
Element .. 177
7.3.5 Design of Radial Beams .. 179
7.3.6 Cost of a Radial Beam .. 180
7.3.7 Additional Cost . 180
7.3.8 Optimization Results .. 181
7.3.9 Conclusions . 181
7.4 A Circular Floor Constructed from Welded Stiffened Steel
Sectorial Plates . 182
7.4.1 Introduction . 182
7.4.2 Problem Formulation . 183
7.4.3 Solution Strategy for the Three Optimization Phases 183
7.4.4 Minimum Cost Design of a Sectorial Plate . 183
7.4.5 Optimum Design of Radial Beams . 188
7.4.6 Optimum Number of Sectorial Plates 190
7.4.7 Cost Comparison with an Unstiffened Thick-Base-Plate
Version .. 191
7.4.8 Conclusions . 193
7.5 Minimum Cost Design of a Cellular Plate Loaded by Uniaxial
Compression .. 193
7.5.1 Introduction . 194
7.5.2 The Basic Formulae of Cellular Plates . 194
7.5.3 The Overall Buckling Constraint . 195
7.5.4 The Cost Function 198
7.5.5 The Optimum Design Data and Results 199
7.5.6 Conclusions . 200
7.6 Minimum Cost Design of a Square Box Column with Walls
Constructed from Cellular Plates with RHS Stiffeners 200
7.6.1 Introduction . 201Contents XVII
7.6.2 Characteristics of Cellular Plates . 202
7.6.3 Minimum Cost Design of the Square Box Column 203
7.6.3.1 Constraint on Overall Buckling of a Cellular Plate
Wall (Fig. 7.21) . 203
7.6.3.2 Constraint on Horizontal Displacement
of the Column Top 205
7.6.3.3 Numerical Data (Fig. 7.20) .. 205
7.6.3.4 Cost Function .. 205
7.6.3.5 Optimization and Results .. 208
7.6.4 Conclusions . 208
8 Cylindrical and Conical Shells 211
8.1 Minimum Cost Design for Various Diameters of a Ring-Stiffened
Cylindrical Shell Loaded by External Pressure 212
8.1.1 Introduction . 212
8.1.2 Characteristics of the Optimization Problem . 213
8.1.3 Constraint on Shell Buckling . 213
8.1.4 Constraint on Ring-Stiffener Buckling . 214
8.1.5 The Cost Function 215
8.1.6 Results of the Optimization 216
8.1.7 Conclusions . 218
8.2 Cost Comparison of Optimized Unstiffened Cylindrical
and Conical Shells for a Cantilever Column Loaded by Axial
Compression and Bending . 218
8.2.1 Introduction . 218
8.2.2 Constraint on Conical Shell Buckling 219
8.2.3 The Cost Function 221
8.2.4 Numerical Data and Results .. 222
8.2.5 Conclusions . 223
8.3 Conical Shell with Non-equidistant Ring-Stiffening Loaded
by External Pressure . 223
8.3.1 Introduction . 223
8.3.2 Design of Shell Segment Lengths 224
8.3.3 Design of a Ring-Stiffener for Each Shell Segment .. 225
8.3.4 The Cost Function 227
8.3.5 Numerical Data . 228
8.3.6 Results of the Optimization 228
8.3.7 Conclusions . 229
Appendix A-D . 231
References . 251
Subject Index .. 263
كلمة سر فك الضغط : books-world.net

The Unzip Password : books-world.net

تحميل

يجب عليك التسجيل في الموقع لكي تتمكن من التحميل

تسجيل | تسجيل الدخول