Contents. Tables. Notation xii Latin upper case letters Latin lower case letters Greek upper case letters Greek lower case letters. Foreword.

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1 Tables x Notation xii Latin upper case letters Latin lower case letters Greek upper case letters Greek lower case letters xii xiv xvi xvi Foreword xviii 1 Introduction Aims of the Manual Eurocode system Scope of the Manual Contents of the Manual Terminology General Changes of axes nomenclature Slenderness Non-contradictory complementary information (NCCI) 7 2 General principles Designing for safety Design process Stability Multi-storey braced structures Single-storey structures Forms of bracing Robustness Movement joints Loading Permanent and variable actions Equivalent forces due to imperfections Second order effects Limit states General Ultimate limit state Serviceability limit states 18 v

2 2.9 Material properties Partial factors for materials Design strength Other properties Properties in fire Brittle fracture Prevention of lamellar tearing Section classification Methods of analysis General approach Joint modelling 27 3 Braced multi-storey buildings General Introduction Actions (loads) Material selection Structural form and framing Stability Framing Flooring Fire resistance Corrosion protection Robustness Introduction Horizontal ties Vertical ties Connections 41 4 Beams Non-composite beams with full lateral restraint Introduction Design procedure Non-composite I and H section beams without full lateral restraint Introduction Design procedure Calculation of relative slenderness Beams with intermediate restraint Other sections without full lateral restraint General Rolled channel sections subject to bending about the major axis Welded I or H sections with equal flanges Welded doubly symmetrical box sections Rolled hollow sections Plates and flats Tee sections Rolled angles General case 56 vi

3 4.4 Composite beams Introduction Construction case Properties of concrete and reinforcement Effective concrete width Vertical shear resistance Bending resistance Shear connectors Spacing and minimum amount of shear connection Transverse shear Serviceability and deflections 67 5 Columns in braced multi-storey buildings Columns Column selection Columns in simple construction Design procedure Columns with additional moments 73 6 Members in bracing systems Introduction Cross sectional areas Buckling lengths and slenderness ratio Resistance of sections in axial compression General Angles in compression Resistance of sections in axial tension General Angles connected by one leg Bending and axial tension (EC3 Part 1-1 cl.6.2.9) 80 7 Single-storey buildings General Introduction Actions (loads) General Permanent actions G Variable actions Q Equivalent horizontal forces Load combinations Material selection Structural form and framing Fire resistance Corrosion protection Bracing Purlins and side rails Roof and cladding materials 86 vii

4 8 Portal frames with pinned bases Introduction Plastic analysis Sizing of rafters and columns Design procedure Sway and snap-through stability General Sway stability check Snap-through stability check Serviceability check deflection Check on position of plastic hinge in rafter and calculation of load resistance Stability checks Restraint of plastic hinges Rafter stability Stability of haunch Stability of column Lattice girders and trusses with pin-base columns Lattice girders and trusses Determination of section sizes Columns for single-storey buildings braced in both directions Columns for single-storey buildings braced in one direction only in the side walls and/or in the valleys Connections Introduction Connection design Bolts Spacing and edge distances Dimensions of holes Design resistance of ordinary bolts Bolts in slip-resistant connections (Category B and C connections) Welds Fillet welds Butt welds Typical connection details Introduction Column bases General Design of base plates Design of bases (moment + axial load) 120 viii

5 11.3 Beam-to-column and beam-to-beam connections in simple construction Beam-to-column web cleats Beam-to-beam web cleats Beam-to-column flexible end plates Beam-to-beam flexible end plates Fin plates Block tearing Column-to-column splices Column bearing splices Column non-bearing splices Portal frame eaves connections General Geometry eaves haunch Resistance of column flange in bending Effective length of equivalent T-stub Web tension in beam or column Final resistance moment Compression checks Column web panel shear Vertical shear Weld sizes Summary of procedure Resistance to transverse forces i.e web bearing and buckling 136 References 137 Appendix A Moment resistances of UB sections 141 Appendix B Resistances of UC sections 148 Contents ix

6 Tables Table 2.1 Values of initial imperfection z 13 Table 2.2 Partial load factors 17 Table 2.3 Typical loadcase combinations 18 Table 2.4 Vertical deflection limits 19 Table 2.5 Horizontal deflection limits 19 Table 2.6 Nominal strengths of steels 21 Table 2.7 Maximum thickness for steelwork in buildings 23 Table 2.8 Selection of width to thickness ratios for classification of elements 26 Table 3.1 Details of typical flooring systems and their relative merits 35 Table 3.2 Fire protection: type of protection 36 Table 3.3 Specifications from CIRIA Table 3.4 Life to first maintenance for external specifications 38 Table 3.5 Environments and life to first maintenance for internal specifications 38 Table 3.6 Building classification for robustness 39 Table 4.1 Section classification for bending only 43 Table 4.2 Simplified expressions for relative slenderness 47 Table 4.3 Determination of C 1 48 Table 4.4 Values of slenderness parameter V 49 Table 4.5 Parameters k and D for simple beams without intermediate restraint 50 Table 4.6 Parameters k and D for a cantilever without immediate restraint 51 Table 4.7 Properties of normal weight concrete 58 Table 4.8 Properties of lightweight concrete 58 Table 4.9 Characteristic resistance of studs 62 Table 4.10 Percentage reinforcement 66 Table 5.1 UB Sections which are not class 4 in direct compression 70 Table 5.2 Selection of buckling curve 73 Table 5.3 Uniform moment factors 74 Table 6.1 Reduction factors b 2 and b 3 80 Table 7.1 Load combinations for single-storey buildings 82 Table 7.2 Typical spacings and spans for single-storey buildings 84 Table 7.3 Lightweight roofing systems and their relative merits 87 Table 10.1 Type of joint model 107 Table 10.2 Bolt spacing and end distance 110 Table 10.3 Nominal clearances for bolts (mm) 110 Table 10.4 Resistance of bolts 111 Table 10.5 Nominal yield strength and ultimate strengths for bolts (used as characteristic values in calculations) 112 Table 10.6 Shear and tensile resistance for class 8.8 bolts 112 Table 10.7 Bearing resistance of class 8.8 ordinary bolts: grade S275 material 113 Table 10.8 Bearing resistance of class 8.8 ordinary bolts: grade S355 material 113 Table 10.9 Resistance of pre-loaded bolts in friction connections 114 x

7 Tables Table Slip resistance of preloaded bolts 114 Table Calculation of resistance of fillet welds 116 Table Fillet weld resistances 116 Table 11.1 Concrete design values and bearing strengths 120 Table 11.2 Expressions for m and e 130 Table 11.3 Resistance of T-stub 131 Table 11.4 Maximum column flange thickness in mm for plastic distribution of bolt forces 133 Table A1 S275 Steel 457 deep and above 141 Table A2 S275 Steel 406 deep and below 143 Table A3 S355 Steel 457 deep and above 144 Table A4 S355 Steel 406 deep and below 146 Table B1 S355 Steel 148 xi

Design of Steel Structures Prof. S.R.Satish Kumar and Prof. A.R.Santha Kumar

Design of Steel Structures Prof. S.R.Satish Kumar and Prof. A.R.Santha Kumar 2.6 Portal frames Portal frames are the most commonly used structural forms for single-storey industrial structures. They are constructed mainly using hot-rolled sections, supporting the roofing and side