The book introduces all the aspects needed for the safe and economic design and analysis of connections using bolted joints in steel structures. This is not treated according to any specific standard but making comparison among the different norms and methodologies used in the engineering practice, e.g. Eurocode, AISC, DIN, BS.
Several examples are solved and illustrated in detail, giving the reader all the tools necessary to tackle also complex connection design problems.
The book is introductory but also very helpful to advanced and specialist audiences because it covers a large variety of practice demands for connection design. Parts that are not taken to an advanced level are seismic design, welds, interaction with other materials (concrete, wood), and cold formed connections./p
Table of Contents
Acknowledgments xxi
List of Abbreviations xxiii
1 Fundamental Concepts of Joints in Design of Steel Structures 1
1.1 Pin Connections and Moment Resisting Connections 1
1.1.1 Safety, Performance, and Costs 1
1.1.2 Lateral Load Resisting System 2
1.1.3 Pins and Fully Restrained Joints in the Analysis Model 7
1.2 Plastic Hinge 8
1.2.1 Base Plates 9
1.2.2 Trusses 11
References 12
2 Fundamental Concepts of the Behavior of Steel Connections 13
2.1 Joint Classifications 13
2.2 Forces in the Calculation Model and for the Connection 14
2.3 Actions Proportional to Stiffness 17
2.4 Ductility 18
2.5 Load Path 19
2.6 Ignorance of the Load Path 20
2.7 Additional Restraints 21
2.8 Methods to Define Ultimate Limit States in Joints 21
2.9 Bolt Resistance 22
2.10 Yield Line 22
2.11 Eccentric Joints 22
2.12 Economy, Repetitiveness, and Simplicity 22
2.13 Man-hours and MaterialWeight 23
2.14 Diffusion Angles 23
2.15 Bolt Pretensioning and Effects on Resistance 24
2.15.1 Is Resistance Affected by Pretensioning? 24
2.15.2 Is Pretensioning Necessary? 24
2.15.3 Which PretensioningMethod Should Be Used? 25
2.16 Transfer Forces 25
2.17 Behavior of a Bolted Shear Connection 25
2.18 Behavior of Bolted Joints Under Tension 27
References 29
3 Limit States for Connection Components 31
3.1 Deformation Capacity (Rotation) and Stiffness 31
3.1.1 Rotational Stiffness 32
3.2 Inelastic Deformation due to Bolt Hole Clearance 33
3.3 Bolt Shear Failure 34
3.3.1 Threads Inside the Shear Plane 35
3.3.2 Number of Shear Planes 37
3.3.3 Packing Plates 37
3.3.4 Long Joints 38
3.3.5 Anchor Bolts 39
3.3.6 Stiffness Coefficient 39
3.4 Bolt Tension Failure 40
3.4.1 Countersunk Bolts 41
3.4.2 Stiffness Coefficient 41
3.5 Bolt Failure in Combined Shear and Tension 42
3.6 Slip-Resistant Bolted Connections 42
3.6.1 Combined Shear and Tension 44
3.7 Bolt Bearing and Bolt Tearing 44
3.7.1 Countersunk Bolts 49
3.7.2 Stiffness Coefficients 49
3.8 Block Shear (or Block Tearing) 49
3.9 Failure ofWelds 52
3.9.1 Weld Calculation Procedures 54
3.9.1.1 DirectionalMethod 54
3.9.1.2 Simplified Method 57
3.9.2 TackWelding (Intermittent FilletWelds) 58
3.9.3 Eccentricity 58
3.9.4 FilletWeld Groups 58
3.9.5 Welding Methods 60
3.9.6 Inspections 60
3.9.6.1 Visual Testing 60
3.9.6.2 Penetrant Testing 60
3.9.6.3 Magnetic Particle Testing 60
3.9.6.4 Radiographic Testing 60
3.9.6.5 Ultrasonic Testing 61
3.10 T-stub, Prying Action 61
3.10.1 T-stub with Prying Action 62
3.10.2 Possible Simplified Approach According to AISC 64
3.10.3 Backing Plates 65
3.10.4 Length Limit for Prying Forces and T-stub without Prying 66
3.10.5 T-stub Design Procedure for Various “Components” According to Eurocode 67
3.10.5.1 Column Flange 67
3.10.5.2 End Plate 71
3.10.5.3 Angle Flange Cleat 71
3.10.6 T-stub Design Procedure for Various “Components” According to the “Green Book” 71
3.10.6.1 𝓁eff for Equivalent T-stubs for Bolt Row Acting Alone 74
3.10.6.2 𝓁eff to Consider for a Bolt Row Acting Alone 77
3.10.6.3 𝓁eff to Consider for Bolt Rows Acting in Group 79
3.10.6.4 Examples of 𝓁eff for Bolts in a Group 80
3.10.7 T-stub for Bolts Outside the Beam Flanges 81
3.10.8 Stiffness Coefficient 81
3.11 Punching 82
3.12 Equivalent Systems 82
3.13 Web Panel Shear 82
3.13.1 Stiffness Coefficient 84
3.14 Web in Transverse Compression 84
3.14.1 Transformation Parameter 𝛽 86
3.14.2 Formulas for Other Local Buckling Limit States 87
3.14.3 Stiffness Coefficient 88
3.14.4 T-stub in Compression 88
3.15 Web in Transverse Tension 88
3.15.1 Stiffness Coefficient 89
3.16 Flange andWeb in Compression 89
3.17 BeamWeb in Tension 89
3.18 Plate Resistance 90
3.18.1 Material Properties 90
3.18.2 Tension 90
3.18.2.1 Staggered Bolts 92
3.18.3 Compression 92
3.18.4 Shear 92
3.18.5 Bending 93
3.18.6 Design for Combined Forces 93
3.18.7 Whitmore Section 93
3.19 Reduced Section of Connected Profiles 93
3.19.1 Shear Lag 95
3.20 Local Capacity 99
3.21 Buckling of Connecting Plates 100
3.21.1 Gusset Plate Buckling 100
3.21.2 Fin Plate (Shear Tab) Buckling 101
3.22 Structural Integrity (and Tie Force) 103
3.23 Ductility 105
3.24 Plate Lamellar Tearing 106
3.25 Other Limit States in Connections with Sheets and Cold-formed Steel Sections 108
3.26 Fatigue 108
3.27 Limit States of Other Materials in the Connection 109
References 109
4 Connection Types: Analysis and Calculation Examples 113
4.1 Common Symbols 113
4.1.1 Materials 113
4.1.2 Design Forces 113
4.1.3 Bolts 113
4.1.4 Geometric Characteristics of Plates and Profiles 114
4.2 Eccentrically Loaded Bolt Group: Eccentricity in the Plane of the Faying Surface 115
4.2.1 Elastic Method 115
4.2.1.1 Example of Eccentricity Calculated with Elastic Method 116
4.2.2 Instantaneous Center-of-Rotation Method 118
4.2.2.1 Example of Eccentricity Calculated with the Instantaneous Center-of-Rotation Method 119
4.3 Eccentrically Loaded Bolt Group: Eccentricity Normal to the Plane of the Faying Surface 120
4.3.1 Neutral Axis at Center of Gravity 121
4.3.1.1 Example of Eccentricity Normal to Plane Calculated with Neutral Axis at Center-of-Gravity Method 122
4.3.2 Neutral Axis Not at Center of Gravity 123
4.3.2.1 Example of Eccentricity Normal to Plane Calculated with Neutral Axis not at Center-of-Gravity Method 124
4.4 Base Plate with Cast Anchor Bolts 125
4.4.1 Plate Thickness 125
4.4.1.1 AISC Method 125
4.4.1.2 Eurocode Method 130
4.4.2 Contact Pressure 135
4.4.2.1 AISC Method 135
4.4.2.2 Eurocode Method 136
4.4.3 Anchor Bolts in Tension 139
4.4.3.1 AISC Method 139
4.4.3.2 Eurocode Method 140
4.4.3.3 Other Notes 141
4.4.4 Welding 142
4.4.5 Shear Resistance 142
4.4.5.1 Friction 142
4.4.5.2 Anchor Bolts in Shear 143
4.4.5.3 Shear Lugs 144
4.4.6 Rotational Stiffness 144
4.4.7 Measures to Improve Ductility 145
4.4.8 Practical Details and Other Notes 145
4.4.9 Fully Restrained Schematization of Column Base Detail 148
4.4.10 Example of Base Plate Design According to Eurocode 149
4.4.10.1 Uplift and Moment 149
4.4.10.2 Shear 152
4.4.10.3 Welding 153
4.4.10.4 Joint Stiffness 153
4.4.10.5 Comparison with AISC Method for SLU1 153
4.5 Chemical or Mechanical Anchor Bolts 153
4.6 Fin Plate/Shear Tab 154
4.6.1 Choices and Possible Variants 155
4.6.1.1 Pin Position 155
4.6.1.2 Location of PlateWelded to Primary Member 156
4.6.1.3 Notches (Copes) in Secondary Member 157
4.6.1.4 Reinforcing BeamWeb 158
4.6.2 Limit States to Be Considered 161
4.6.3 Rotation Capacity 161
4.6.4 Measures to Improve Ductility 162
4.6.5 Measures to Improve Structural Integrity 162
4.6.6 Design Example According to DIN 162
4.6.6.1 Bolt Shear 163
4.6.6.2 Bearing 165
4.6.6.3 Block Shear 166
4.6.6.4 Plate Resistance 167
4.6.6.5 Beam Resistance 167
4.6.6.6 Plate Buckling 168
4.6.6.7 Local Check for Primary-BeamWeb 168
4.6.6.8 Welding 168
4.6.6.9 Rotation Capacity 169
4.6.6.10 Ductility 169
4.6.6.11 Structural Integrity 169
4.7 Double-Bolted Simple Plate 169
4.7.1 Rotation Capacity 170
4.7.2 Ductility 170
4.7.3 Structural Integrity 171
4.7.4 Beam-to-Beam Example Designed According to Eurocode 171
4.7.4.1 Bolt Shear 172
4.7.4.2 Bearing 173
4.7.4.3 Block Shear 174
4.7.4.4 Plate Resistance 174
4.7.4.5 Beam Resistance 174
4.7.4.6 Plate Buckling 174
4.7.4.7 Primary-BeamWeb Local Check 174
4.7.4.8 Welding, Ductility, and Structural Integrity 174
4.8 Shear (“Flexible”) End Plate 175
4.8.1 Variants and Rotation Capacity 175
4.8.2 Limit States to be Considered 177
4.8.3 Rotational Stiffness 177
4.8.4 Ductility 178
4.8.5 Structural Integrity 178
4.8.6 Column-to-Beam Example Designed According to IS 800 178
4.8.6.1 Bolt Resistance 179
4.8.6.2 Rotation Capacity and Structural Integrity 179
4.8.6.3 Bearing 180
4.8.6.4 Block Shear 180
4.8.6.5 Plate Check 180
4.8.6.6 Beam Shear Check 180
4.8.6.7 Column Resistance 180
4.8.6.8 Welds 181
4.8.6.9 Conclusion 181
4.9 Double-Angle Connection 181
4.9.1 Variants 183
4.9.2 Limit States to Be Considered 183
4.9.3 Structural Integrity, Ductility, and Rotation Capacity 183
4.9.4 Practical Advice 183
4.9.5 Beam-to-Beam Example Designed According to AISC 184
4.10 Connections in Trusses 186
4.10.1 Intermediate Connections for Compression Members 186
4.11 Horizontal End Plate Leaning on a Column 188
4.11.1 Limit States to be Considered 189
4.12 Rigid End Plate 189
4.12.1 ColumnWeb Panel Shear 191
4.12.2 Lever Arm 191
4.12.3 Stiffeners 192
4.12.4 SupplementaryWeb Plate Check 193
4.12.5 Check for Column Stiffeners in Compression Zone 193
4.12.6 Check for Column Stiffeners in Tension Zone 195
4.12.7 Check of Column Diagonal Stiffener for Panel Shear 196
4.12.8 Shear Due to Vertical Forces 196
4.12.9 Design with Haunches 196
4.12.10 Beam-to-Beam Connections 196
4.12.11 BS Provisions 197
4.12.12 AISC Approach 197
4.12.13 Limit States to Be Considered 199
4.12.14 Rotational Stiffness 200
4.12.15 Simplifying the Design 201
4.12.16 Practical Advice 201
4.12.17 Structural Integrity, Ductility, and Rotation Capacity 201
4.12.18 Beam-to-Column End-Plate Design Example According to Eurocode 202
4.12.18.1 Column FlangeThickness Check for Bolt Row 1 204
4.12.18.2 ColumnWeb Tension Check for Bolt Row 1 204
4.12.18.3 Beam End-Plate Thickness Check for Bolt Row 1 205
4.12.18.4 BeamWeb Tension Check for Bolt Row 1 205
4.12.18.5 Final Resistant Value for Bolt Row 1 205
4.12.18.6 Column FlangeThickness Check for Bolt Row 2 Individually 205
4.12.18.7 ColumnWeb Tension Check for Bolt Row 2 Individually 206
4.12.18.8 Beam End-Plate Thickness Check for Bolt Row 2 Individually 206
4.12.18.9 BeamWeb Tension Check for Bolt Row 2 Individually 206
4.12.18.10 Column Flange Thickness Check for Bolt Row 2 in Group with Bolt Row 1 207
4.12.18.11 ColumnWeb Tension Check for Bolt Row 2 in Group with Bolt Row 1 207
4.12.18.12 Beam End-PlateThickness Check for Bolt Row 2 in Group with Bolt Row 1 207
4.12.18.13 BeamWeb Tension Check for Bolt Row 2 in Group with Bolt Row 1 207
4.12.18.14 Final Resistant Value for Bolt Row 2 208
4.12.18.15 Vertical Shear 208
4.12.18.16 Web Panel Shear 209
4.12.18.17 ColumnWeb Resistance to Transverse Compression 209
4.12.18.18 Stiffener Design 210
4.12.18.19 Welds 210
4.12.18.20 Rotational Stiffness 210
4.13 Splice 212
4.13.1 Calculation Model and Limit States 213
4.13.2 Structural Integrity, Ductility, and Rotation Capacity 215
4.13.3 Column Splice Design Example According to AS 4100 215
4.13.3.1 Flanges 216
4.13.3.2 Web 217
4.13.3.3 Conclusions and Final Considerations 217
4.13.3.4 Possible Alternative 217
4.14 Brace Connections 217
4.14.1 AISC Methods: UFM and KISS 220
4.14.1.1 KISS Method 222
4.14.1.2 Uniform Force Method 222
4.14.1.3 UFM Variant 1 223
4.14.1.4 UFM Variant 2 224
4.14.1.5 UFM Variant 3 225
4.14.1.6 UFM Adapted to Existing Connections 226
4.14.2 Practical Recommendations 227
4.14.3 Complex Brace Connection Example According to CSA S16 227
4.14.3.1 Friction Connection for Brace 227
4.14.3.2 Brace and Gusset Bearing 228
4.14.3.3 Block Shear 228
4.14.3.4 Channel Shear Lag 229
4.14.3.5 Whitmore Section for Tension Resistance and Buckling of Gusset Plate 229
4.14.3.6 UFM Forces 229
4.14.3.7 Gusset-to-Column Shear Tab 229
4.14.3.8 Gusset-to-BeamWeld 229
4.14.3.9 Beam-to-Column Shear Tab 229
4.14.3.10 Ductility and Structural Integrity 230
4.15 Seated Connection 230
4.16 Connections for Girts and Purlins 233
4.17 Welded Hollow-Section Joints 236
4.18 Connections in Composite (Steel-Concrete) Structures 236
4.19 Joints with Bolts andWeldsWorking in Parallel 236
4.20 Expansion Joints 237
4.21 Perfect Hinges 238
4.22 Rollers 239
4.23 Rivets 240
4.24 Seismic Connections 241
4.24.1 Rigid End Plate 242
4.24.2 Braces 243
4.24.3 Eccentric Braces and “Links” 244
4.24.4 Base Plate 244
References 246
5 Choosing the Type of Connection 249
5.1 Priority to Fabricator and Erector 249
5.2 Considerations of Pros and Cons of Some Types of Connections 249
5.3 Shop Organization 250
5.3.1 Plates or Sheets 250
5.3.2 Concept of “Handling” One Piece 250
5.4 Culture 252
References 252
6 Practical Notes on Fabrication 253
6.1 Design Standardizations 253
6.1.1 Materials 253
6.1.2 Thicknesses 253
6.1.3 Bolt Diameters 253
6.2 Dimension of Bolt Holes 254
6.2.1 Bolt Hole Clearance in Base Plates 255
6.3 Erection 256
6.3.1 Structure Lability 256
6.3.2 Erection Sequence and Clearances 256
6.3.3 Bolt Spacing and Interferences 257
6.3.4 Positioning and Supports 257
6.3.5 Holes orWelded Plates for Handling and Lifting 258
6.4 Clearance Needed to Operate TighteningWrenches 258
6.4.1 Double Angles in Connections 259
6.5 Bolt Spacing and Edge Distances 260
6.6 Root Radius Encroachment 260
6.7 Notches 264
6.8 Bolt Tightening and Pretensioning 265
6.8.1 CalibratedWrench 266
6.8.2 Turn of the Nut 266
6.8.3 Direct Tension Indicators 270
6.8.4 Twist-Off Type Bolts 271
6.8.5 HydraulicWrenches 273
6.9.1 Tapered (Beveled)Washers 275
6.9.2 Vibrations 277
6.10 Dimensions of Screws, Nuts, andWashers 277
6.10.1 Depth of Bolt Heads and Nuts 277
6.10.2 WasherWidth and Thickness 277
6.11 Reuse of Bolts 278
6.12 Bolt Classes 279
6.13 Shims 280
6.14 Galvanization 281
6.14.1 Tubes 281
6.14.2 PlateWelded over Profiles as Reinforcement 281
6.14.3 Base Plates 282
6.15 Other Finishes After Fabrication 282
6.16 Camber 283
6.17 Grout in Base Plates 284
6.18 Graphical Representation of Bolts and Connections 286
6.19 FieldWelds 287
6.20 Skewed Joints 287
References 291
7 Connection Examples 293
Index 355
