Cold-formed steel structures to the AISI specification

This volume reveals the behaviour and design of cold-formed steel structures, connections and systems. It describes the AISI Specification for the Design of Cold-Formed Steel Structural Members published in July 2000, which governs the design of all cold-formed steel frames, including roof, wall and racking systems, and cold-formed steel residential construction in the USA. The text offers worked examples which can be programmed using MATHCAD or EXCEL.

Author Notes

Gregory J. Hancock is the BHP Steel Professor of Steel Structures in the Department of Civil Engineering at the University of Sydney, New South Wales, Australia
Thomas M. Murray is the Montague-Betts Professor of Structural Steel Design, Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg
Duane S. Ellifritt is Emeritus Professor of Civil Engineering at the University of Florida, Gainesville

Preface	p. v
1. Introduction	p. 1
1.1 Definition	p. 1
1.2 Brief History of Cold-Formed Steel Usage	p. 1
1.3 The Development of a Design Standard	p. 2
1.4 History of Cold-Formed Standards	p. 3
1.5 Common Section Profiles and Applications of Cold-Formed Steel	p. 5
1.6 Manufacturing Processes	p. 13
1.6.1 Roll Forming	p. 13
1.6.2 Brake Forming	p. 14
1.7 General Approach to the Design of Cold-Formed Sections	p. 16
1.7.1 Special Problems	p. 16
1.7.2 Local Buckling and Post-Local Buckling of Thin Plate Elements	p. 16
1.7.3 Effective Width Concept	p. 17
1.7.4 Propensity for Twisting	p. 20
1.7.5 Distortional Buckling	p. 20
1.7.6 Cold Work of Forming	p. 22
1.7.7 Web Crippling Under Bearing	p. 23
1.7.8 Connections	p. 24
1.7.9 Corrosion Protection	p. 26
1.7.10 Inelastic Reserve Capacity	p. 27
1.8 Two Design Methods	p. 27
1.8.1 Allowable Stress Design	p. 28
1.8.2 Load and Resistance Factor Design	p. 28
1.9 Load Combinations	p. 29
References	p. 30
2. Materials and Cold Work of Forming	p. 33
2.1 Steel Standards	p. 33
2.2 Typical Stress-Strain Curves	p. 37
2.3 Ductility	p. 41
2.4 Effects of Cold Work on Structural Steels	p. 46
2.5 Corner Properties of Cold-Formed Sections	p. 49
2.6 Fracture Toughness	p. 52
References	p. 54
3. Buckling Modes of Thin-Walled Members in Compression and Bending	p. 57
3.1 Introduction to the Finite Strip Method	p. 57
3.2 Singly-Symmetric Column Study	p. 60
3.2.1 Unlipped Channel	p. 60
3.2.2 Lipped Channel	p. 64
3.2.3 Lipped Channel (Fixed Ended)	p. 69
3.3 Purlin Section Study	p. 71
3.3.1 Channel Section	p. 71
3.3.2 Z-Section	p. 73
3.4 Hollow Flange Beam in Bending	p. 74
References	p. 76
4. Stiffened and Unstiffened Compression Elements	p. 79
4.1 Local Buckling	p. 79
4.2 Postbuckling of Plate Elements in Compression	p. 81
4.3 Effective Width Formulae for Imperfect Elements in Pure Compression	p. 84
4.4 Effective Width Formulae for Imperfect Elements Under Stress Gradient	p. 89
4.4.1 Stiffened Elements	p. 89
4.4.2 Unstiffened Elements	p. 90
4.5 Effective Width Formulae for Elements with Stiffeners	p. 90
4.5.1 Edge-Stiffened Elements	p. 90
4.5.2 Intermediate Stiffened Elements with One Intermediate Stiffener	p. 93
4.5.3 Intermediate Stiffeners for Edge-Stiffened Elements with an Intermediate Stiffener, and Stiffened Elements with More than One Intermediate Stiffener	p. 93
4.6 Examples	p. 95
4.6.1 Hat Section in Bending	p. 95
4.6.2 Hat Section in Bending with Intermediate Stiffener in Compression Flange	p. 100
4.6.3 C-Section Purlin in Bending	p. 106
4.6.4 Z-Section Purlin in Bending	p. 115
References	p. 124
5. Flexural Members	p. 127
5.1 General	p. 127
5.2 Torsional-Flexural (Lateral) Buckling	p. 129
5.2.1 Elastic Buckling of Unbraced Simply Supported Beams	p. 129
5.2.2 Continuous Beams and Braced Simply Supported Beams	p. 134
5.2.3 Bending Strength Design Equations	p. 141
5.3 Basic Behavior of C- and Z-Section Flexural Members	p. 142
5.3.1 Linear Response of C- and Z-Sections	p. 142
5.3.1.1 General	p. 142
5.3.1.2 Sections with Lateral Restraint Only	p. 143
5.3.1.3 Sections with Lateral and Torsional Restraint	p. 145
5.3.2 Stability Considerations	p. 148
5.4 Bracing	p. 153
5.5 Inelastic Reserve Capacity	p. 155
5.5.1 Sections with Flat Elements	p. 155
5.5.2 Cylindrical Tubular Members	p. 157
5.6 Example: Simply Supported C-Section Beam	p. 158
References	p. 163
6. Webs	p. 167
6.1 General	p. 167
6.2 Webs in Shear	p. 168
6.2.1 Shear Buckling	p. 168
6.2.2 Shear Yielding	p. 170
6.3 Webs in Bending	p. 172
6.4 Webs in Combined Bending and Shear	p. 174
6.5 Web Stiffeners	p. 176
6.6 Web Crippling	p. 176
6.6.1 Edge Loading Alone	p. 176
6.6.2 Combined Bending and Web Crippling	p. 179
6.7 Webs with Holes	p. 182
6.8 Example: Combined Bending with Web Crippling of Hat Section	p. 184
References	p. 186
7. Compression Members	p. 189
7.1 General	p. 189
7.2 Elastic Member Buckling	p. 190
7.3 Stub Column Axial Strength	p. 194
7.4 Long Column Axial Strength	p. 195
7.5 Effect of Local Buckling of Singly-Symmetric Sections	p. 198
7.6 Examples	p. 202
7.6.1 Square Hollow Section Column	p. 202
7.6.2 Unlipped Channel Column	p. 205
7.6.3 Lipped Channel Column	p. 210
References	p. 220
8. Members in Combined Axial Load and Bending	p. 221
8.1 Combined Axial Compressive Load and Bending: General	p. 221
8.2 Interaction Equations for Combined Axial Compressive Load and Bending	p. 223
8.3 Singly Symmetric Sections Under Combined Axial Compressive Load and Bending	p. 227
8.3.1 Sections Bent in a Plane of Symmetry	p. 227
8.3.2 Sections Bent About an Axis of Symmetry	p. 231
8.4 Combined Axial Tensile Load and Bending	p. 231
8.5 Examples	p. 233
8.5.1 Unlipped Channel Section Beam-Column Bent in Plane of Symmetry	p. 233
8.5.2 Unlipped Channel Section Beam-Column Bent About Plane of Symmetry	p. 238
8.5.3 Lipped Channel Section Beam-Column Bent in Plane of Symmetry	p. 242
References	p. 248
9. Connections	p. 251
9.1 Introduction to Welded Connections	p. 251
9.2 Fusion Welds	p. 255
9.2.1 Groove Welds in Butt Joints	p. 255
9.2.2 Fillet Welds Subject to Transverse Loading	p. 256
9.2.3 Fillet Welds Subject to Longitudinal Loading	p. 258
9.2.4 Combined Longitudinal and Transverse Fillet Welds	p. 260
9.2.5 Flare Groove Welds	p. 261
9.2.6 Arc Spot Welds (Puddle Welds)	p. 262
9.2.7 Arc Seam Welds	p. 268
9.3 Resistance Welds	p. 269
9.4 Introduction to Bolted Connections	p. 269
9.5 Design Formulae and Failure Modes for Bolted Connections	p. 272
9.5.1 Tearout Failure of Sheet (Type I)	p. 272
9.5.2 Bearing Failure of Sheet (Type II)	p. 275
9.5.3 Net Section Tension Failure (Type III)	p. 276
9.5.4 Shear Failure of Bolt (Type IV)	p. 279
9.6 Screw Fasteners	p. 280
9.7 Rupture	p. 283
9.8 Examples	p. 285
9.8.1 Welded Connection Design Example	p. 285
9.8.2 Bolted Connection Design Example	p. 291
9.8.3 Screw Fastener Design Example (LRFD Method)	p. 294
References	p. 295
10. Metal Building Roof and Wall Systems	p. 297
10.1 Introduction	p. 297
10.2 Specific AISI Design Methods for Purlins	p. 302
10.2.1 General	p. 302
10.2.2 R-Factor Design Method for Through-Fastened Panel Systems and Uplift Loading	p. 303
10.2.3 The Base Test Method for Standing Seam Panel Systems	p. 304
10.3 Continuous Purlin Line Design	p. 310
10.4 System Anchorage Requirements	p. 318
10.4.1 Z-Purlin Supported Systems	p. 318
10.4.2 C-Purlin Supported Systems	p. 328
10.5 Examples	p. 329
10.5.1 Computation of R-value from Base Tests	p. 329
10.5.2 Continuous Lapped Z-Section Purlin	p. 332
10.5.3 Anchorage Force Calculations	p. 346
References	p. 350
11. Steel Storage Racking	p. 353
11.1 Introduction	p. 353
11.2 Loads	p. 355
11.3 Methods of Structural Analysis	p. 358
11.3.1 Upright Frames	p. 358
11.3.2 Beams	p. 360
11.3.3 Stability of Truss-Braced Upright Frames	p. 361
11.4 Effects of Perforations (Slots)	p. 361
11.4.1 Section Modulus of Net Section	p. 362
11.4.2 Form Factor (Q)	p. 363
11.5 Member Design Rules	p. 363
11.5.1 Flexural Design Curves	p. 364
11.5.2 Column Design Curves	p. 364
11.6 Example	p. 366
References	p. 374
12. Direct Strength Method	p. 375
12.1 Introduction	p. 375
12.2 Elastic Buckling Solutions	p. 376
12.3 Strength Design Curves	p. 378
12.3.1 Local Buckling	p. 378
12.3.2 Flange-Distortional Buckling	p. 381
12.3.3 Overall Buckling	p. 383
12.4 Direct Strength Equations	p. 384
12.5 Examples	p. 386
12.5.1 Lipped Channel Column (Direct Strength Method)	p. 386
12.5.2 Simply Supported C-Section Beam	p. 389
References	p. 391
Index	p. 393

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Author Notes

Table of Contents