Code of Practice for the Structural Use of Steel

Foreword………………………………………………………………..i

Acknowledgments………………………………………………………………..    ii

Contents……………………………………………………………….. …………iii

List of Figures ………………………………………………………………………………….xiv

List of Tables ………………………………………………………………..xvi

1 GENERAL…………………………………………………………………………………………..1

1.1 Scope……………………………………………………………………………………………. 1      

1.2 Design Philosophy……………………………………………………………………………2      
1.2.1 Aims of structural design………………………………………………………………………………………2
1.2.2 Design responsibility and assumptions…………………………………………………………………..2
1.2.3 Structural system, integrity and robustness…………………………………………………………….3
1.2.4 Overall stability……………………………………………………………………………………………………3
1.2.5 Limit state design ………………………………………………………………………………………………..3
1.2.6 Economy ……………………………………………………………………………………………………………3
1.2.7 Design working life………………………………………………………………………………………………3
1.3 References………………………………………………………………………………………………………………..4
1.4 Glossary of Terms and Definitions …………………………………………………………………………….4
1.4.1 General definitions ………………………………………………………………………………………………4
1.4.2 Structural element definitions………………………………………………………………………………..5
1.4.3 Structural behaviour definitions……………………………………………………………………………..6
1.4.4 Material behaviour definitions ……………………………………………………………………………….7
1.4.5 Section type definitions………………………………………………………………………………………..7
1.4.6 Connection definitions………………………………………………………………………………………….8
1.5 Major Symbols…………………………………………………………………………………………………………..8
2 LIMIT STATE DESIGN PHILOSOPHY ………………………………………………………………………..17
2.1 General……………………………………………………………………………………………………………………17
2.1.1 Introduction ………………………………………………………………………………………………………17
2.1.2 Simple design …………………………………………………………………………………………………..17
2.1.3 Continuous design …………………………………………………………………………………………….17
2.1.4 Semi-continuous design……………………………………………………………………………………..17
2.1.5 Design justification by tests…………………………………………………………………………………17
2.1.6 Performance-based design…………………………………………………………………………………17
2.1.7 Calculation accuracy………………………………………………………………………………………….18
2.1.8 Foundation design …………………………………………………………………………………………….18
2.2 Limit State Philosophy …………………………………………………………………………………………….18
2.3 Ultimate Limit States (ULS)………………………………………………………………………………………19
2.3.1 Limit state of strength…………………………………………………………………………………………19
2.3.2 Stability limit states ……………………………………………………………………………………………19
2.3.3 Fatigue …………………………………………………………………………………………………………….20
2.3.4 Structural integrity and robustness ………………………………………………………………………23
2.3.5 Brittle fracture……………………………………………………………………………………………………26
2.4 Serviceability Limit States (SLS)………………………………………………………………………………26
2.4.1 Serviceability loads ……………………………………………………………………………………………26
2.5 Loading …………………………………………………………………………………………………………………..26
2.5.1 General ……………………………………………………………………………………………………………26
2.5.2 Dead and imposed loading …………………………………………………………………………………26
2.5.3 Wind loading …………………………………………………………………………………………………….26
2.5.4 Loads from earth and water pressure…………………………………………………………………..27
2.5.5 Load effects from differential settlement of foundations ………………………………………….27
2.5.6 Load effects from temperature change…………………………………………………………………27
2.5.7 Loads from cranes …………………………………………………………………………………………….27
2.5.8 Notional horizontal forces …………………………………………………………………………………..28
2.5.9 Exceptional loads and loads on key elements……………………………………………………….29
iii
2.5.10 Loads during construction…………………………………………………………………………………..29
2.5.11 Loads on temporary works in construction ……………………………………………………………29
3 MATERIALS …………………………………………………………………………………………………………….30
3.1 Structural Steel………………………………………………………………………………………………………..30
3.1.1 General ……………………………………………………………………………………………………………30
3.1.2 Design strength for normal strength steels……………………………………………………………31
3.1.3 Design strength for high strength steels ……………………………………………………………….35
3.1.4 Uncertified steel ………………………………………………………………………………………………..35
3.1.5 Through thickness properties………………………………………………………………………………35
3.1.6 Other properties ………………………………………………………………………………………………..35
3.2 Prevention of Brittle Fracture …………………………………………………………………………………..36
3.3 Bolts ……………………………………………………………………………………………………………………….38
3.3.1 Normal bolts……………………………………………………………………………………………………..38
3.3.2 High strength friction grip or preloaded bolts…………………………………………………………38
3.4 Welding Consumables……………………………………………………………………………………………..38
3.5 Steel Castings and Forgings ……………………………………………………………………………………38
3.6 Materials for Grouting of Baseplates………………………………………………………………………..38
3.7 Materials for Composite Construction………………………………………………………………………38
3.7.1 Concrete…………………………………………………………………………………………………………..38
3.7.2 Reinforcement…………………………………………………………………………………………………..38
3.7.3 Profiled steel sheets…………………………………………………………………………………………..39
3.7.4 Shear studs………………………………………………………………………………………………………39
3.8 Cold-formed Steel Material Properties………………………………………………………………………39
3.8.1 Mechanical properties………………………………………………………………………………………..39
4 LOAD FACTORS AND MATERIAL FACTORS ……………………………………………………………42
4.1 Partial Safety Factors ………………………………………………………………………………………………42
4.2 Material Factors……………………………………………………………………………………………………….42
4.2.1 Steel plates and sections……………………………………………………………………………………42
4.2.2 Bolts ………………………………………………………………………………………………………………..43
4.2.3 Reinforcement and concrete in composite design………………………………………………….43
4.2.4 Grout for base plates and wall plates …………………………………………………………………..43
4.3 Load Factors and Combinations………………………………………………………………………………43
4.3.1 Load combinations for normal ultimate limit state…………………………………………………..43
4.3.2 Load combinations for overhead traveling cranes………………………………………………….44
4.3.3 Load combinations for building assessment………………………………………………………….44
4.3.4 Load combinations for temporary works in construction …………………………………………44
4.3.5 Load combinations for exceptional events…………………………………………………………….44
4.3.6 Summary of partial load factors …………………………………………………………………………..45
4.3.7 Load combinations for serviceability limit states…………………………………………………….45
5 SERVICEABILITY LIMIT STATES………………………………………………………………………………46
5.1 General……………………………………………………………………………………………………………………46
5.2 Deflection………………………………………………………………………………………………………………..46
5.3 Wind-induced Oscillation…………………………………………………………………………………………47
5.3.1 Wind sensitive buildings and structures………………………………………………………………..47
5.3.2 Serviceability limit state………………………………………………………………………………………47
5.3.3 Dynamic structural characteristics ……………………………………………………………………….47
5.3.4 Serviceability criteria for tall buildings…………………………………………………………………..47
5.3.5 Serviceability criteria for communication and broadcasting towers…………………………..48
5.3.6 Reduction of wind-induced dynamic response ………………………………………………………48
5.4 Human Induced Floor Vibration ……………………………………………………………………………….48
5.5 Durability…………………………………………………………………………………………………………………49
5.5.1 General ……………………………………………………………………………………………………………49
5.5.2 Types of protection against corrosion…………………………………………………………………..49
5.5.3 Corrosion from residual stresses …………………………………………………………………………51
6 DESIGN METHODS AND ANALYSIS …………………………………………………………………………52
6.1 Methods of Analysis ………………………………………………………………………………………………..52
iv
6.2 Analysis Models and Assumptions…………………………………………………………………………..53
6.3 Frame Classification………………………………………………………………………………………………..53
6.3.1 General ……………………………………………………………………………………………………………53
6.3.2 Elastic critical load factor ……………………………………………………………………………………53
6.3.3 Non-sway frames ………………………………………………………………………………………………54
6.3.4 Sway frames …………………………………………………………………………………………………….54
6.3.5 Sway ultra-sensitive frames………………………………………………………………………………..54
6.4 Imperfections…………………………………………………………………………………………………………..54
6.4.1 General ……………………………………………………………………………………………………………54
6.4.2 Frame imperfections ………………………………………………………………………………………….55
6.4.3 Member imperfections ……………………………………………………………………………………….55
6.4.4 Elastic critical mode …………………………………………………………………………………………..56
6.5 Simple Design …………………………………………………………………………………………………………56
6.6 First-order Linear Elastic Analysis (First-order Indirect Analysis)……………………………..56
6.6.1 General ……………………………………………………………………………………………………………56
6.6.2 Moment amplification for sway frames …………………………………………………………………57
6.6.3 Effective length for sway and non-sway frames …………………………………………………….57
6.6.4 Maximum slenderness ratio………………………………………………………………………………..59
6.7 Second-order P-Δ-only Elastic Analysis (Second-order Indirect Analysis)…………………59
6.7.1 General ……………………………………………………………………………………………………………59
6.7.2 Method of analysis …………………………………………………………………………………………….59
6.7.3 Applications and limitations…………………………………………………………………………………59
6.8 Second-order P-Δ–δ Elastic Analysis (Second-order Direct Analysis) ………………………..60
6.8.1 General ……………………………………………………………………………………………………………60
6.8.2 Method of analysis …………………………………………………………………………………………….60
6.8.3 Applications and limitations…………………………………………………………………………………60
6.9 Advanced Analysis ………………………………………………………………………………………………….61
6.9.1 General ……………………………………………………………………………………………………………61
6.9.2 Method of analysis …………………………………………………………………………………………….61
6.9.3 Applications and limitations…………………………………………………………………………………61
6.10 Bracing Members…………………………………………………………………………………………………….61
6.11 Connection Classification in Analysis………………………………………………………………………62
6.11.1 Pinned connections……………………………………………………………………………………………62
6.11.2 Rigid connections………………………………………………………………………………………………62
6.11.3 Semi-rigid connections……………………………………………………………………………………….62
7 SECTION CLASSIFICATION……………………………………………………………………………………..63
7.1 General……………………………………………………………………………………………………………………63
7.2 Classification…………………………………………………………………………………………………………..64
7.3 Stress Ratios for Classification………………………………………………………………………………..68
7.4 Flanges of Compound I- or H-sections……………………………………………………………………..69
7.5 Effective Plastic Modulus…………………………………………………………………………………………70
7.5.1 General ……………………………………………………………………………………………………………70
7.5.2 I- or H-sections with equal flanges……………………………………………………………………….70
7.5.3 Rectangular hollow sections ……………………………………………………………………………….70
7.5.4 Circular hollow sections ……………………………………………………………………………………..71
7.6 Effective Width Method for Slender Cross-sections………………………………………………….71
7.7 Effective Stress Method for Slender Cross-sections…………………………………………………71
7.8 Shift of the Centroid of the Effective Cross-section ………………………………………………….72
8 DESIGN OF STRUCTURAL MEMBERS ……………………………………………………………………..74
8.1 General……………………………………………………………………………………………………………………74
8.2 Restrained Beams……………………………………………………………………………………………………74
8.2.1 Shear capacity ………………………………………………………………………………………………….74
8.2.2 Moment capacity……………………………………………………………………………………………….75
8.2.3 Beams with web openings ………………………………………………………………………………….76
8.2.4 Castellated beams …………………………………………………………………………………………….77
8.3 Lateral-Torsional Buckling of Beams ……………………………………………………………………….78
8.3.1 Intermediate and end lateral restraints …………………………………………………………………78
8.3.2 Torsional restraint ……………………………………………………………………………………………..79
v
8.3.3 Normal and destabilizing loads……………………………………………………………………………79
8.3.4 Effective length for lateral-torsional buckling …………………………………………………………79
8.3.5 Moment resistance to lateral-torsional buckling……………………………………………………..81
8.4 Plate Girders……………………………………………………………………………………………………………88
8.4.1 Design strength…………………………………………………………………………………………………88
8.4.2 Minimum web thickness for serviceability……………………………………………………………..88
8.4.3 Minimum web thickness to avoid compression flange buckling ……………………………….88
8.4.4 Moment capacity of restrained girders………………………………………………………………….88
8.4.5 Effects of axial force…………………………………………………………………………………………..89
8.4.6 Shear buckling resistance…………………………………………………………………………………..89
8.4.7 Intermediate transverse web stiffeners…………………………………………………………………89
8.4.8 End anchorage………………………………………………………………………………………………..104
8.4.9 Panels with openings……………………………………………………………………………………….104
8.4.10 Web capacity and stiffeners design ……………………………………………………………………104
8.4.11 Other types of stiffeners……………………………………………………………………………………107
8.4.12 Connections between web stiffeners and webs……………………………………………………107
8.4.13 Connections between web stiffeners and flanges ………………………………………………..107
8.5 Buckling Resistance Moment for Single Angle Members ………………………………………..108
8.6 Tension Members…………………………………………………………………………………………………..108
8.6.1 Tension capacity ……………………………………………………………………………………………..108
8.6.2 Members with eccentric connections………………………………………………………………….108
8.6.3 Single and double angle, channel and T-sections………………………………………………..108
8.6.4 Double angle, channel and T-sections with intermediate connections…………………….109
8.7 Compression Members ………………………………………………………………………………………….109
8.7.1 Segment length……………………………………………………………………………………………….109
8.7.2 Effective length in general…………………………………………………………………………………109
8.7.3 Restraints……………………………………………………………………………………………………….110
8.7.4 Slenderness ……………………………………………………………………………………………………110
8.7.5 Compression resistance …………………………………………………………………………………..110
8.7.6 Compressive strength………………………………………………………………………………………111
8.7.7 Eccentric connections………………………………………………………………………………………126
8.7.8 Simple construction………………………………………………………………………………………….126
8.7.9 Effective length of sections in triangulated structures and trusses………………………….126
8.8 Tension Members under Combined Axial Force and Moments………………………………..127
8.9 Compression Members under Combined Axial Force and Moments………………………..128
8.9.1 Cross-section capacity……………………………………………………………………………………..128
8.9.2 Member buckling resistance ……………………………………………………………………………..128
8.10 Torsional and Flexural-Torsional Buckling of Compression Members …………………….131
8.11 Portal Frames ………………………………………………………………………………………………………..131
8.11.1 General ………………………………………………………………………………………………………….131
8.11.2 Elastic design………………………………………………………………………………………………….131
8.11.3 Plastic design………………………………………………………………………………………………….131
8.11.4 In-plane stability ………………………………………………………………………………………………131
8.11.5 Out-of-plane stability………………………………………………………………………………………..134
8.12 Laced and Battened Struts …………………………………………………………………………………….138
8.12.1 Laced struts…………………………………………………………………………………………………….138
8.12.2 Battened struts………………………………………………………………………………………………..138
Appendix 8.1 …………………………………………………………………………………………………………………..140
Appendix 8.2 …………………………………………………………………………………………………………………..141
Appendix 8.3 …………………………………………………………………………………………………………………..142
Appendix 8.4 …………………………………………………………………………………………………………………..143
9 CONNECTIONS………………………………………………………………………………………………………144
9.1 General………………………………………………………………………………………………………………….144
9.2 Welded Connections………………………………………………………………………………………………145
9.2.1 Through-thickness tension………………………………………………………………………………..145
9.2.2 Types of welds ………………………………………………………………………………………………..145
9.2.3 Weldability and electrodes………………………………………………………………………………..145
9.2.4 Welded connections to unstiffened flanges …………………………………………………………145
9.2.5 Strength of welds …………………………………………………………………………………………….146
vi
9.3 Bolted Connections ……………………………………………………………………………………………….153
9.3.1 Bolt spacing…………………………………………………………………………………………………….153
9.3.2 End and edge distances …………………………………………………………………………………..153
9.3.3 Hole dimensions ……………………………………………………………………………………………..154
9.3.4 Sectional area of connected parts ……………………………………………………………………..154
9.3.5 Block shear …………………………………………………………………………………………………….156
9.3.6 Design strength of bolts under shear and bearing………………………………………………..156
9.3.7 Design strength of bolts in tension……………………………………………………………………..160
9.3.8 Combined shear and tension…………………………………………………………………………….161
9.3.9 Bolts combined with welds………………………………………………………………………………..161
9.3.10 Pin connections……………………………………………………………………………………………….161
9.3.11 Connections for hollow sections of lattice girders…………………………………………………163
9.4 Baseplate and Anchor Construction……………………………………………………………………….163
9.4.1 Column base plates …………………………………………………………………………………………163
9.4.2 Anchor bolts for base plates, wall plates and hangers ………………………………………….164
9.5 Steel Castings and Forgings ………………………………………………………………………………….166
10 COMPOSITE CONSTRUCTION ……………………………………………………………………………….167
10.1 Materials………………………………………………………………………………………………………………..167
10.1.1 Structural steel ………………………………………………………………………………………………..167
10.1.2 Concrete…………………………………………………………………………………………………………167
10.1.3 Reinforcement…………………………………………………………………………………………………168
10.1.4 Shear connectors…………………………………………………………………………………………….168
10.1.5 Profiled steel sheets…………………………………………………………………………………………168
10.2 Composite Beams………………………………………………………………………………………………….169
10.2.1 General ………………………………………………………………………………………………………….169
10.2.2 Analysis of internal forces and moments …………………………………………………………….171
10.2.3 Establishment of composite cross-sections…………………………………………………………173
10.2.4 Classification of composite cross-sections ………………………………………………………….174
10.2.5 Section capacities and properties of composite cross-sections ……………………………..176
10.2.6 Ultimate limit state design…………………………………………………………………………………179
10.2.7 Serviceability limit state design………………………………………………………………………….181
10.3 Shear Connection ………………………………………………………………………………………………….185
10.3.1 General ………………………………………………………………………………………………………….185
10.3.2 Design resistance of shear connectors……………………………………………………………….185
10.3.3 Provision of shear connectors……………………………………………………………………………188
10.3.4 Detailing of shear connectors ……………………………………………………………………………190
10.3.5 Transverse reinforcement…………………………………………………………………………………191
10.4 Composite Slabs with Profiled Steel Sheets……………………………………………………………195
10.4.1 General ………………………………………………………………………………………………………….195
10.4.2 Form of construction ………………………………………………………………………………………..195
10.4.3 Limit state design …………………………………………………………………………………………….196
10.4.4 Design of profiled steel sheets in construction stage ……………………………………………198
10.4.5 Design of composite slabs in composite stage…………………………………………………….200
10.4.6 Detailing provisions………………………………………………………………………………………….207
10.4.7 Constructional details……………………………………………………………………………………….209
10.5 Composite Columns ………………………………………………………………………………………………211
10.5.1 General ………………………………………………………………………………………………………….211
10.5.2 General method of design…………………………………………………………………………………212
10.5.3 Simplified method of design………………………………………………………………………………213
10.5.4 Shear connection and load introduction ……………………………………………………………..224
10.5.5 Detailing provisions………………………………………………………………………………………….227
11 DESIGN OF COLD-FORMED STEEL OPEN SECTIONS, SHEET PROFILES,
HOLLOW SECTIONS AND SHEET PILE SECTIONS …………………………………………………229
11.1 General Design of Open Sections and Sheet Profiles ……………………………………………..229
11.2 Material Properties…………………………………………………………………………………………………230
11.2.1 Physical properties…………………………………………………………………………………………..230
11.2.2 Mechanical properties………………………………………………………………………………………230
11.3 Section Properties …………………………………………………………………………………………………231
vii
11.3.1 Gross section properties…………………………………………………………………………………..231
11.3.2 Effective section properties under tension…………………………………………………………..232
11.3.3 Effective section properties under compression and bending………………………………..232
11.3.4 Local buckling …………………………………………………………………………………………………232
11.3.5 Flange curling …………………………………………………………………………………………………238
11.4 Members under Lateral Loads………………………………………………………………………………..239
11.4.1 General ………………………………………………………………………………………………………….239
11.4.2 Moment capacity……………………………………………………………………………………………..239
11.4.3 Shear capacity ………………………………………………………………………………………………..240
11.4.4 Combined bending and shear……………………………………………………………………………241
11.4.5 Web crushing capacity……………………………………………………………………………………..241
11.4.6 Combined bending and web crushing ………………………………………………………………..245
11.4.7 Lateral buckling……………………………………………………………………………………………….246
11.4.8 Calculation of deflection……………………………………………………………………………………249
11.4.9 Effects of torsion ……………………………………………………………………………………………..250
11.5 Members under Axial Loads …………………………………………………………………………………..250
11.5.1 Members under tension ……………………………………………………………………………………250
11.5.2 Members under compression ……………………………………………………………………………252
11.5.3 Flexural buckling ……………………………………………………………………………………………..252
11.5.4 Flexural-torsional buckling ………………………………………………………………………………..255
11.5.5 Combined compression and bending …………………………………………………………………256
11.6 Connections ………………………………………………………………………………………………………….257
11.6.1 General recommendations………………………………………………………………………………..257
11.6.2 Fastenings with bolts ……………………………………………………………………………………….257
11.6.3 Fastenings with screws and blind rivets ……………………………………………………………..259
11.6.4 Interconnections in compound members…………………………………………………………….260
11.6.5 Bolted moment connections of compound members ……………………………………………262
11.7 Design for Hollow Sections ……………………………………………………………………………………264
11.7.1 General design for hollow sections…………………………………………………………………….264
11.7.2 Material properties …………………………………………………………………………………………..264
11.7.3 Mechanical properties………………………………………………………………………………………264
11.7.4 Control of external corner profile ……………………………………………………………………….264
11.7.5 Welding at cold-formed zones …………………………………………………………………………..265
11.7.6 Cold formed section properties under loading……………………………………………………..265
11.7.7 Calculation of deflection……………………………………………………………………………………265
11.7.8 Connections ……………………………………………………………………………………………………265
11.8 Design for Cold-formed Sheet Pile Sections …………………………………………………………..266
11.8.1 General design for sheet pile sections………………………………………………………………..266
11.8.2 Material properties …………………………………………………………………………………………..266
11.8.3 Mechanical properties………………………………………………………………………………………266
11.8.4 Minimum inside radii for cold-formed sheet piles………………………………………………….266
11.8.5 Welding at cold-formed zones of cold-formed sheet piles……………………………………..267
11.8.6 Cold-formed section properties under loading……………………………………………………..267
11.8.7 Calculation of deflection……………………………………………………………………………………267
12 FIRE RESISTANT DESIGN………………………………………………………………………………………268
12.1 Design Principles…………………………………………………………………………………………………..268
12.1.1 Basic requirements of fire resistance for a structure …………………………………………….268
12.1.2 Fire exposure ………………………………………………………………………………………………….268
12.1.3 Fire limit states………………………………………………………………………………………………..269
12.1.4 Physical and mechanical properties at elevated temperatures ………………………………269
12.1.5 Material factors and load factors………………………………………………………………………..272
12.2 Fire Resistance Derived from Standard Fire Tests ………………………………………………….273
12.2.1 Fire resistances of structural members……………………………………………………………….273
12.2.2 Failure criteria for standard fire tests ………………………………………………………………….273
12.3 Fire Resistance Derived from Limiting Temperature Method …………………………………..274
12.4 Fire Resistance Derived from Performance-Based Design Methods………………………..275
12.4.1 Basis of analysis ……………………………………………………………………………………………..275
12.4.2 Thermal response ……………………………………………………………………………………………275
12.4.3 Mechanical response……………………………………………………………………………………….275
viii
12.4.4 Validation of performance-based design methods ……………………………………………….276
12.4.5 Simplified calculation methods…………………………………………………………………………..276
12.5 Performance Requirements ……………………………………………………………………………………276
13 PERFORMANCE-BASED DESIGN GUIDANCE FOR PARTICULAR TYPES OF
STRUCTURES, INCLUDING GUIDANCE ON GENERAL MAINTENANCE OF
STEEL STRUCTURES…………………………………………………………………………………………….277
13.1 High-Rise Buildings……………………………………………………………………………………………….277
13.1.1 Structural systems for high-rise buildings……………………………………………………………277
13.1.2 Stability issues for high-rise buildings…………………………………………………………………277
13.1.3 Considerations for particular details …………………………………………………………………..277
13.1.4 Considerations for design against extreme events……………………………………………….278
13.1.5 Wind engineering for high-rise buildings……………………………………………………………..278
13.2 Guidance on Design of Transmission Towers, Masts and Chimneys……………………….279
13.2.1 Structural systems for transmission towers, masts and chimneys ………………………….279
13.2.2 Overall stability of towers, masts and chimneys…………………………………………………..279
13.2.3 Particular details ……………………………………………………………………………………………..280
13.2.4 Considerations for design against extreme events……………………………………………….280
13.2.5 Serviceability issues…………………………………………………………………………………………280
13.2.6 Design issues for steel chimneys ………………………………………………………………………280
13.2.7 Construction and corrosion protection of steel chimneys ………………………………………281
13.2.8 Wind-excited oscillations of circular chimneys……………………………………………………..281
13.3 Glass and Façade Supporting Structures ……………………………………………………………….282
13.3.1 General ………………………………………………………………………………………………………….282
13.3.2 Deflection limit…………………………………………………………………………………………………282
13.3.3 Requirements………………………………………………………………………………………………….282
13.3.4 Loadings and actions……………………………………………………………………………………….283
13.3.5 Tensioning structural systems …………………………………………………………………………..283
13.4 Temporary Works in Construction………………………………………………………………………….284
13.4.1 Design philosophy……………………………………………………………………………………………284
13.4.2 Second-order effects………………………………………………………………………………………..285
13.4.3 Out-of-plumbness ……………………………………………………………………………………………285
13.4.4 Fitness tolerance……………………………………………………………………………………………..285
13.4.5 Member imperfections ……………………………………………………………………………………..285
13.4.6 Support settlements and flexible supports…………………………………………………………..285
13.4.7 Over-turning ……………………………………………………………………………………………………285
13.4.8 Tolerance and clearance ………………………………………………………………………………….286
13.4.9 New and used systems…………………………………………………………………………………….286
13.4.10 Module testing…………………………………………………………………………………………………286
13.5 Long Span Structures…………………………………………………………………………………………….287
13.5.1 Systems for long span structures ………………………………………………………………………287
13.5.2 Overall stability of long span structures ………………………………………………………………287
13.5.3 Particular details ……………………………………………………………………………………………..287
13.5.4 Considerations for design against extreme events……………………………………………….287
13.5.5 Serviceability issues…………………………………………………………………………………………287
13.6 Footbridges …………………………………………………………………………………………………………..288
13.6.1 Design philosophy……………………………………………………………………………………………288
13.6.2 Loads …………………………………………………………………………………………………………….288
13.6.3 Design for strength, deflection and fatigue ………………………………………………………….288
13.6.4 Vibration and oscillation……………………………………………………………………………………290
13.6.5 Bearing design for footbridges…………………………………………………………………………..291
13.7 Design Loads from Overhead Runway Cranes, Tower and Derrick Cranes and
Mobile Cranes ………………………………………………………………………………………………….291
13.7.1 Types and classifications of static cranes……………………………………………………………291
13.7.2 Design issues for crane support structures …………………………………………………………291
13.7.3 Loading from cranes ………………………………………………………………………………………..291
13.8 Guidance on Maintenance of Steel Structures ………………………………………………………..293
13.8.1 General ………………………………………………………………………………………………………….293
13.8.2 Consideration of maintenance in the original design…………………………………………….293
13.8.3 Maintenance of existing structures …………………………………………………………………….294
ix
13.8.4 Health and safety issues on maintenance…………………………………………………………..294
14 FABRICATION AND ERECTION………………………………………………………………………………295
14.1 Dimensions and Tolerances of Sections…………………………………………………………………295
14.2 Workmanship – General…………………………………………………………………………………………295
14.2.1 Identification……………………………………………………………………………………………………295
14.2.2 Handling…………………………………………………………………………………………………………295
14.2.3 Cutting……………………………………………………………………………………………………………295
14.2.4 Shaping and forming………………………………………………………………………………………..295
14.2.5 Holing…………………………………………………………………………………………………………….296
14.2.6 Assembly………………………………………………………………………………………………………..297
14.2.7 Curving and straightening…………………………………………………………………………………297
14.2.8 Inspection……………………………………………………………………………………………………….297
14.2.9 Storage…………………………………………………………………………………………………………..298
14.3 Workmanship – Welding ………………………………………………………………………………………..298
14.3.1 General ………………………………………………………………………………………………………….298
14.3.2 Welder qualification………………………………………………………………………………………….298
14.3.3 Welding procedure specifications ………………………………………………………………………298
14.3.4 Assembly………………………………………………………………………………………………………..299
14.3.5 Non-destructive testing of parent material…………………………………………………………..300
14.3.6 Non-destructive testing of welds (NDT) ………………………………………………………………300
14.3.7 Shear stud welding ………………………………………………………………………………………….307
14.4 Workmanship – Bolting………………………………………………………………………………………….307
14.4.1 General ………………………………………………………………………………………………………….307
14.4.2 Ordinary bolted assemblies ………………………………………………………………………………307
14.4.3 Pre-loaded bolt assemblies……………………………………………………………………………….309
14.5 Workmanship – Erection………………………………………………………………………………………..310
14.5.1 Erection method statement……………………………………………………………………………….310
14.5.2 Handling and storage……………………………………………………………………………………….310
14.5.3 Damaged steelwork …………………………………………………………………………………………311
14.5.4 Column base plates and slabs…………………………………………………………………………..311
14.5.5 Grouting …………………………………………………………………………………………………………311
14.5.6 Stability…………………………………………………………………………………………………………..311
14.5.7 Alignment of part of the structure……………………………………………………………………….311
14.5.8 Temperature effects…………………………………………………………………………………………311
14.5.9 Site welding…………………………………………………………………………………………………….311
14.5.10 Site bolting ……………………………………………………………………………………………………..311
14.6 Protective Treatment ……………………………………………………………………………………………..312
14.6.1 General ………………………………………………………………………………………………………….312
14.6.2 Materials…………………………………………………………………………………………………………312
14.6.3 Surface preparation …………………………………………………………………………………………312
14.6.4 Sprayed metal coatings ……………………………………………………………………………………312
14.6.5 Hot-dip galvanizing ………………………………………………………………………………………….313
14.6.6 Paint treatments………………………………………………………………………………………………313
14.6.7 Inspection and testing………………………………………………………………………………………313
15 ACCURACY OF FABRICATION AND ERECTION ……………………………………………………..314
15.1 General………………………………………………………………………………………………………………….314
15.2 Permitted Deviations in the Cross Section of Rolled Components…………………………..314
15.3 Permitted Deviations in Components after Fabrication……………………………………………315
15.3.1 Squareness of end not prepared for bearing……………………………………………………….315
15.3.2 Squareness of ends prepared for bearing …………………………………………………………..315
15.3.3 Straightness of both axes or of individual webs of flanges…………………………………….315
15.3.4 Length ……………………………………………………………………………………………………………315
15.3.5 Curved or cambered ………………………………………………………………………………………..315
15.3.6 Squareness at bearing……………………………………………………………………………………..315
15.4 Permitted Deviations for Elements of Fabricated Members……………………………………..316
15.4.1 Position of fittings…………………………………………………………………………………………….316
15.4.2 Position of holes………………………………………………………………………………………………316
15.4.3 Punched holes ………………………………………………………………………………………………..316
x
15.4.4 Shared or cropped edges of plates or angles………………………………………………………316
15.4.5 Flatness………………………………………………………………………………………………………….316
15.4.6 Notches………………………………………………………………………………………………………….316
15.4.7 Column base plates and caplates………………………………………………………………………316
15.5 Permitted Deviations in Plate Girder Sections ………………………………………………………..317
15.5.1 Depth……………………………………………………………………………………………………………..317
15.5.2 Flange width……………………………………………………………………………………………………317
15.5.3 Squareness of section ……………………………………………………………………………………..317
15.5.4 Web eccentricity………………………………………………………………………………………………317
15.5.5 Flanges ………………………………………………………………………………………………………….317
15.5.6 Top flange of crane girder…………………………………………………………………………………317
15.5.7 Web distortion …………………………………………………………………………………………………317
15.5.8 Cross section at bearings …………………………………………………………………………………317
15.6 Permitted Deviations in Fabricated Box Sections……………………………………………………318
15.6.1 Plate widths…………………………………………………………………………………………………….318
15.6.2 Squareness…………………………………………………………………………………………………….318
15.6.3 Plate distortion ………………………………………………………………………………………………..318
15.7 Permitted Deviations of Stiffeners ………………………………………………………………………….318
15.7.1 Web stiffeners …………………………………………………………………………………………………318
15.7.2 Web stiffeners …………………………………………………………………………………………………318
15.8 Permitted Deviations of Lattice Components ………………………………………………………….319
15.8.1 Panel length ……………………………………………………………………………………………………319
15.8.2 Cumulative length of panels………………………………………………………………………………319
15.8.3 Joint eccentricity ……………………………………………………………………………………………..319
15.8.4 Overall cross section………………………………………………………………………………………..319
15.8.5 Tubular lattice girders ………………………………………………………………………………………319
15.9 Permitted Deviations of Cold Formed Sections ………………………………………………………320
15.9.1 Position of measurement ………………………………………………………………………………….320
15.9.2 Thickness……………………………………………………………………………………………………….320
15.9.3 External dimensions…………………………………………………………………………………………320
15.9.4 Length ……………………………………………………………………………………………………………320
15.9.5 Angular tolerance…………………………………………………………………………………………….320
15.9.6 Straightness ……………………………………………………………………………………………………320
15.9.7 Angle of twist…………………………………………………………………………………………………..321
15.9.8 Compound members ……………………………………………………………………………………….321
15.9.9 Flatness………………………………………………………………………………………………………….321
15.10 Permitted Deviations for Foundations, Walls and Holding Down Bolts ……………………322
15.10.1 Foundation level………………………………………………………………………………………………322
15.10.2 Vertical wall…………………………………………………………………………………………………….322
15.10.3 Pre-set foundation bolt or bolt groups when prepared for adjustment …………………….322
15.10.4 Pre-set foundation bolt or bolt groups when not prepared for adjustment ……………….322
15.10.5 Pre-set wall bolt or bolt groups when not prepared for adjustment …………………………322
15.10.6 Embedded steel anchor plate ……………………………………………………………………………322
15.11 Application of Permitted Deviation for Erected Components…………………………………..323
15.12 Permitted Deviations of Erected Components and Structures…………………………………323
15.12.1 Position of columns at base………………………………………………………………………………323
15.12.2 Overall plan dimensions……………………………………………………………………………………323
15.12.3 Single storey columns plumb…………………………………………………………………………….323
15.12.4 Multi-storey columns plumb ………………………………………………………………………………323
15.12.5 Alignment of columns at splice ………………………………………………………………………….324
15.12.6 Location of column splice………………………………………………………………………………….324
15.12.7 Gap between bearing surfaces………………………………………………………………………….324
15.12.8 Alignment of adjacent perimeter columns……………………………………………………………324
15.12.9 Beam level ……………………………………………………………………………………………………..324
15.12.10 Level at each end of same beam……………………………………………………………………….324
15.12.11 Level of adjacent beams within a distance of 5 metres …………………………………………324
15.12.12 Level of beams at adjacent floors ………………………………………………………………………325
15.12.13 Beam alignement …………………………………………………………………………………………….325
15.12.14 Position in plan of members………………………………………………………………………………325
15.12.15 Crane gantry column plumb………………………………………………………………………………325
xi
15.12.16 Crane gantries gauge of rail tracks…………………………………………………………………….325
15.12.17 Joints in gantry crane rails – rail surface …………………………………………………………….325
15.12.18 Joints in gantry crane rails – rail edge ………………………………………………………………..326
15.12.19 Profile steel floor decking………………………………………………………………………………….326
15.12.20 Thickness of bedding……………………………………………………………………………………….326
15.12.21 Position on bearing ………………………………………………………………………………………….326
16 LOADING TESTS……………………………………………………………………………………………………327
16.1 General………………………………………………………………………………………………………………….327
16.1.1 Scope…………………………………………………………………………………………………………….327
16.1.2 Requirement for testing…………………………………………………………………………………….327
16.1.3 Recommendations for conduct of tests ………………………………………………………………327
16.2 Proof, Strength and Failure Tests …………………………………………………………………………..328
16.2.1 Proof and strength tests……………………………………………………………………………………328
16.2.2 Failure test ……………………………………………………………………………………………………..329
16.3 Test Conditions, Methods and Procedures……………………………………………………………..329
16.3.1 Test conditions………………………………………………………………………………………………..329
16.3.2 Loading and unloading……………………………………………………………………………………..329
16.3.3 Measurements ………………………………………………………………………………………………..330
16.3.4 Material properties …………………………………………………………………………………………..330
16.3.5 Relative strength coefficient………………………………………………………………………………330
16.3.6 Quality control of load testing…………………………………………………………………………….330
16.3.7 Contents of test report ……………………………………………………………………………………..330
16.4 Testing of Composite Slabs……………………………………………………………………………………331
16.4.1 General ………………………………………………………………………………………………………….331
16.4.2 Specific tests…………………………………………………………………………………………………..331
16.4.3 Parametric tests ………………………………………………………………………………………………334
17 GUIDANCE FOR EVALUATION AND MODIFICATION OF EXISTING STRUCTURES…..337
17.1 General Approach………………………………………………………………………………………………….337
17.2 Structural Assessment Survey……………………………………………………………………………….337
17.2.1 Original materials …………………………………………………………………………………………….337
17.2.2 Appraisal report……………………………………………………………………………………………….338
17.3 Design and Analysis Issues……………………………………………………………………………………338
17.3.1 Structural appraisal analysis and design check……………………………………………………338
17.3.2 Overall stability of existing and new structure………………………………………………………338
17.3.3 Details for connection of new to old structure………………………………………………………338
17.3.4 Upgrading of original structure…………………………………………………………………………..338
17.3.5 Considerations for design against extreme events (fire, accident, terrorism) …………..339
17.3.6 Serviceability issues…………………………………………………………………………………………339
17.4 Load Tests …………………………………………………………………………………………………………….339
ANNEX A REFERENCES…………………………………………………………………………………………….340
A1 Acceptable Standards and References …………………………………………………………………..340
A1.1 Steel materials ………………………………………………………………………………………………..340
A1.2 Castings and forgings ………………………………………………………………………………………341
A1.3 Bolts ………………………………………………………………………………………………………………342
A1.4 Welding ………………………………………………………………………………………………………….345
A1.5 Materials for composite design ………………………………………………………………………….348
A1.6 Shear studs…………………………………………………………………………………………………….348
A1.7 Cold-formed steel materials………………………………………………………………………………348
A1.8 Dimensions and tolerances of sections ………………………………………………………………349
A1.9 Protective treatment…………………………………………………………………………………………351
A1.10 Other acceptable references……………………………………………………………………………..351
A2 Informative References ………………………………………………………………………………………….352
A2.1 Practice Notes for Authorized Persons and Registered Structural Engineers…………..352
A2.2 The Steel Construction Institute, UK…………………………………………………………………..352
A2.3 UK and European Standards …………………………………………………………………………….352
A2.4 Australian Standards………………………………………………………………………………………..353
A2.5 General references ………………………………………………………………………………………….353
xii
ANNEX B RELATIVE STRENGTH COEFFICIENT …………………………………………………………355
B1 General………………………………………………………………………………………………………………….355
B2 Predetermination of the Test Load for a Strength Test ……………………………………………355
B3 Processing the Results of a Failure Test…………………………………………………………………355
ANNEX C TYPICAL WELDING SYMBOLS……………………………………………………………………357
ANNEX D NOTES ON TESTING TO ESTABLISH STEEL CLASS AND ESSENTIALS OF
SOME PRODUCT STANDARDS…………………………………………………………………..361
D1 Testing to Establish Steel Class……………………………………………………………………………..361
D1.1 Essential requirements for hot rolled and hot finished steel…………………………………..361
D1.2 Additional requirements for high strength steels…………………………………………………..363
D1.3 Design strength for high strength steels ……………………………………………………………..363
D1.4 Quality control of testing …………………………………………………………………………………..363
D2 Abstract of Essential Requirements for Bolts …………………………………………………………365