HB48-1999 Steel structures design handbook

HB 48—1999 

STEEL STRUCTURES DESIGN HANDBOOK 

Accessed by UNSW - LIBRARY on 05 Oct 2002 

i

National Library of Australia 

Cataloguing in Publication Data 

Steel Structures Design Handbook 

Standards Australia 

1 The Crescent, Homebush NSW 

ISBN 0 7337 2754 9 

Copyright – Standards Australia 

First published 1993 

Second edition 1999 


© Copyright ⎯ STANDARDS AUSTRALIA 

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ii

STEEL STRUCTURES DESIGN HANDBOOK 

Edited by: 

L. Pham 

P. Boxhall 

D. Mansell 


Publishers 

Standards Australia 

1 The Crescent, Homebush 

NSW Australia 2140 

iii

The first edition of this Handbook was prepared by a consortium of design, 

construction and research engineers. 

This Edition has been reviewed by the Institution of Engineers Australia’s National Committee 

on Structural Engineering. 


iv

Preface 

Notation 

Index 

CONTENTS 

Page 

vii 

ix 

xiii 

Part I 

Simplified Design Rules 

Chapter 

1 Scope and General 2 

2 Materials 4 

3 Design 6 

4 Methods of Structural Analysis 14 

5 Members Subject to Bending 21 

6 Members Subject to Axial Compression 41 

7 Members Subject to Axial Tension 50 

8 Members Subject to Combined Action 51 

9 Connections 52 

10 Brittle Fracture 64 

11 Fatigue 65 

Appendix 

A Alternative Method for Moment Amplification 67 

B Alternative Method for Members Subject to Combined Actions 73 

Part II 

Design Aids 

Connection Capacity, Bolts 

Connection Capacity, Welds 

Universal Section Capacities 

Welded Section Capacities 

Design Moment Capacity of Universal Sections 

for Given Effective Length 

Design Moment Capacity of Welded Sections 

for Given Effective Length 

D1 

D2 

D3-D4 

D5-D6 

D7-D16 

D17-D24 

(continued overleaf) 


v

Part III 

Worked Examples 

Introduction 


1 Example 1 

Design of Elements of a Braced Frame 

• Problem 1.1 

Design of a Simply-Supported Beam 


Design of a Simply-Supported Beam with Axial 

Compression 


Design of a Column with Biaxial Bending 

2 Example 2 

Design of Elements of a Portal Frame 


Design of a Member Under Combined Compression and 

Bending 


Design of the Rafter and a Column Under Tension 


Design of a Haunch 

3 Example 3 

Design of a Roof Truss 


Design of a Web Member 


Design of a Bottom Chord 


Design of a Top Chord 

4 Example 4 

Design of a Transporter Support Beam 


Bearing Capacity Under Wheel Load 


Bending Strength of a Cantilevered Beam 


Design of Web Stiffeners at Beam Support 


Assessment of Fatigue Life 

E1/2 

E1/4 

E1/6 

E2/1 

E2/4 

E2/5 

E3/1 

E3/2 

E3/3 

E4/2 

E4/3 

E4/4 

E4/6 

vi

PREFACE 

This second edition of the Handbook is an update of the 1993 edition to incorporate: 

• The amendments to the Steel Structures Standard embodied in AS 4100—1998 

• The replacement of BHP Grade 250 steel sections with 300PLUS sections 

• Changes to the available range of sizes of BHP steel sections. 

As a consequence of 300PLUS becoming the standard grade for hot-rolled steel 

sections, most rules, tables, design aids and examples relating to sections of grade 250 

have been replaced with ones corresponding to grade 300. Designers requiring 

information relating to grade 250 should consult the 1993 edition. 

The preface to the 1993 edition outlines the essential features of the Handbook and is 

reproduced below. It is unchanged apart from an updating of the recommended 

publications in the final paragraph. 

Preface to the 1993 edition 

The first Australian Limit States Design Standard for Steel Structures, AS 4100—1990, 

incorporates material which permits a more advanced approach to some design 

problems than is found in most other Standards. It is written in such a way that, in some 

instances, designers may choose to use simpler options with some penalty in the design 

capacity of the members in the sense that their design would be more conservative. 

Incorporating various tiers of design in one Standard may make the total document less 

convenient than it could be for those designers who wish to do most of their work in the 

lower tier mode. 

To overcome this drawback, this Handbook offers a lower tier design method on its 

own, providing rules and procedures which will result in designs fulfilling the 

requirements of AS 4100. The reader will find the appropriate cross-referencing to 

AS 4100 which may be needed in some circumstances. 

The use of AS 4100 may enable the designer to justify a greater capacity in a given 

member than can be demonstrated by the use of this Handbook. There is therefore a 

price to be paid for the simplicity of the rules contained herein. In most instances, 

however, the effect on the combined cost of design and materials will be marginal. 


The Handbook contains three parts and each member of the consortium of engineers 

who wrote it participated as author of the design rules, or author of the worked 

examples, or as editorial adviser representative of future users. Therefore, the 

consortium includes research engineers from CSIRO and the universities, and designers 

from large and small practices, and from the construction and fabrication industries. It is 

believed that the outcome is a book which is technically sound, and well-suited to use 

by a designer who wishes to make decisions with minimal design aids and only a handheld 

calculator. The users of this Handbook are assumed to be qualified to undertake 

structural design. 

vii

Part I of the book provides advice and rules in a structure similar to that of the first 

eleven sections of AS 4100. The chapter and paragraph numbers, titles, and notation, 

are kept as close to those of AS 4100 as possible so that designers can move readily 

from one document to the other in order to use the tier of their choice. 

Chapter 1 sets out the scope and the limitations for the use of this Handbook and 

Chapter 2 lists the relevant standards with which the materials should comply. 

Chapter 3 describes the difference between Working Stress and Limit States Design and 

describes the classes of Limit States which should be anticipated. It also sets 

serviceability limits. Chapter 4 defines the methods of analysis for the purposes of 

obtaining design effects and displacements, the forms of construction, the assumptions 

for analysis and the limitations to the use of plastic analysis in this Handbook. 

Chapters 5 to 8 provide rules and procedures for calculating the strength of members 

subjected to flexural, compressive, tensile and combined actions. Chapter 9 recognizes 

the fact that a large part of Australian structural practice uses a very limited and discrete 

range of fasteners. It therefore also contains simple tables of bolt and weld capacities, 

and of the relevant geometric data on hole sizes and edge distances. 

Chapter 10 identifies circumstances under which brittle fracture is not likely to be a 

problem. Chapter 11 presents a simplified approach to design against fatigue. Advice is 

given only on situations where the stress range is constant and material is thin. The form 

of expression of the S-N curves is simplified by changing the definition of the detail 

category to reduce the number of ‘variables’ in the equations. The structure of 

Chapter 11 is such that the designer will often be able quickly to exempt the detail from 

fatigue analysis with little or no computation. A more fundamental change in 

philosophy is that the Handbook enables the designer to calculate the life of the detail 

when it is fatigue-prone. 

Part II is a set of design aids in the form of tables and charts derived from the 

dimensions of standard sections and from the rules in the Chapters of this Handbook. 

They speed up the design process and reduce the opportunity for computational error. 

Part III consists of worked examples of the application of the rules in Part I. The 

examples are chosen to demonstrate realistic situations and have been worked out by 

designers in active commercial practice. 


Users of the Handbook are expected to have a copy of the tables of section properties 

(published by BHP under the title Hot Rolled and Structural Steel Products 1998), and 

would find their work expedited even further by having access to Design Capacity 

Tables for Structural Steel, 2 nd ed, Vol 1: Open Sections published in 1994 by the 

Australian Institute of Steel Construction (AISC) and DuraGal Design Capacity Tables 

for Steel Hollow Sections produced in 1996 by Tubemakers Structural and Pipeline 

Products (now BHP Structural and Pipeline Products). For reference to higher tier 

methods, designers should use this Handbook together with AS 4100. 

viii

NOTATION 


A c = minor diameter area of a bolt, as defined in AS 1275 

A g = gross area of a cross-section 

A n = net area of a cross-section; or 

= sum of the net areas of the flanges and the gross area of the web 

A o = plain shank area of a bolt 

A s 

= tensile stress area of a bolt as defined in AS 1275; or 

= area of a stiffener or stiffeners in contact with a flange; or 

= area of an intermediate web stiffener 

A w = gross sectional area of a web 

a e = minimum distance from the edge of a hole to the edge of a ply 

measured in the direction of the component of a force plus half the 

bolt diameter 

b = width; or 

= clear width of an element outstand from the face of a supporting 

plate element; or 

= clear width of a supported element between faces of supporting 

plate elements 

b b , b bf = bearing widths defined in Para. 2.2.3 

b es = stiffener outstand from the face of a web 

b f = width of an RHS Section 

b s = stiff bearing length 

b w = depth of an RHS Section 

c m = factor for unequal moments 

d = depth of a section; or 

= depth of preparation for incomplete penetration butt weld; or 

= maximum cross-sectional dimension of a member 

d f = diameter of a fastener (bolt or pin) 

d h = hole diameter 

d o = overall section depth including out-of-square dimensions; or 

= overall section depth of a segment; or 

= outside diameter of a circular hollow section 

d p = clear transverse dimension of a web panel 

d v = coped web depth 

d 1 = depth of a web 

d 3 , d 4 = depths of preparation for incomplete penetration butt welds 

E = young’s modulus of elasticity, 200 × 10 3 MPa 

F * = total design load on a member between supports 

f u = tensile strength used in design 

f uf = minimum tensile strength of a bolt 

f up = tensile strength of a ply 

f uw = nominal tensile strength of weld metal 

f y = yield stress used in design 

f ys = yield stress of a stiffener used in design 

f 3 = detail category fatigue strength at constant amplitude fatigue limit 

f * = design stress range 

G = shear modulus of elasticity, 80 × 10 3 MPa; or 

= nominal dead load 

G R = part of the dead load tending to resist instability 

ix


H * = design horizontal force 

h = height to the eave of a portal frame 

h s = storey height 

I = second moment of area of a cross-section 

I c = I of a column 

I r = I of a rafter 

I s = I of a pair of stiffeners or a single stiffener about centreline of web 

I w = warping constant for a cross-section 

I y = I about the cross-section minor principal y-axis 

J = torsion constant for a cross-section 

k = modifying factor 

k e = member effective length factor 

k f = form factor for members subject to axial compression 

k h = factor for different hole types 

= load height effective length factor 

= factor for pin rotation 

= effective length factor for restraint against lateral rotation; or 

= effective length factor for a restraining member; or 

k l = load height factor 

k r = lateral rotation restraint factor 

= reduction factor to account for the length of a bolted or welded lap 

splice connection 

k ss = factor for type of shear stress distribution 

k t = twist restraint effective length factor; or 

= correction factor for distribution of forces in a tension member 

l = span; or 

= member length; or 

= segment or sub-segment length 

l b = length between points of effective bracing or restraint 

l c = distance between adjacent column centres 

l e = effective length of a compression member = k e l; or 

= effective length of a laterally unrestrained member 

l e /r = geometrical slenderness ratio 

l h = slotted hole length 

l j = length of a bolted lap splice connection 

l w = greatest internal dimension of an opening in a web; or 

= length of a fillet weld in a welded lap splice connection 

M b = nominal member moment capacity 

M bx , M by = M b about major principal x-axis, and minor principal y-axis, 

respectively 

M o = nominal out-of-plane member moment capacity; or 

= reference elastic buckling moment for a member subject to 

bending 

M ox = enhanced nominal out-of-plane member moment capacity about 

major principal x-axis 

M rbx , M rby = reduced nominal capacity in bending of member about major x- 

axis and minor y-axis, respectively 

M rsx = M s about major principal x-axis reduced by axial force 

M rsy = M s about minor principal y-axis reduced by axial force 

M s = nominal section moment capacity 

x


M sx = M s about major principal x-axis 

M sy = M s about minor principal y-axis 

M tx = lesser of M rsx and M ox 

M * = design bending moment (amplified from first order analysis) 

M * m = maximum calculated design bending moment along the length of a 

member or in a segment using first order analysis 

M * x = design bending moment about major principal x-axis 

M * y = design bending moment about minor principal y-axis 

N c = nominal member capacity in compression 

N omb = elastic flexural buckling load for a braced member (= π 2 EI/(k e l) 2 ) 

N s = nominal section capacity of a compression member; or 

= nominal section capacity for axial load 

N t = nominal member capacity in tension 

N tf = nominal tension capacity of a bolt 

n ti = minimum bolt tension at installation; or 

tension induced in a bolt during installation 

N * = design axial force, tensile or compressive 

* 

N tf = design tensile force on a bolt 

n ei = number of effective interfaces 

n i = number of stress cycles 

n n = number of shear planes with threads intercepting the shear plane 

= for bolted connections 

n x = number of shear planes without threads intercepting the shear 

plane for bolted connections 

n max = maximum number of stress cycles 

P c = the average of the computed first order compression forces in the 

columns of a portal frame 

P r = the average of the computed first order compression forces in the 

rafters of a portal frame 

Q = nominal live load 

Q * = design transverse force; or 

= design live load 

r = radius of gyration 

R = nominal total design resistance 

R bb = nominal bearing buckling capacity 

R by = nominal bearing yield capacity 

R sb = nominal buckling capacity of a stiffened web 

R sy = nominal yield capacity of a stiffened web 

R u 

= nominal capacity 

R * = design bearing force; or 

= design reaction 

r y = radius of gyration about minor principal y-axis 

S * = design action 

s = length of rafter from eave to ridge 

t = thickness; or 

= thickness of thinner part joined; or 

= wall thickness of a circular hollow section; or 

= thickness of an angle section 

t f = thickness of a flange; or 

= thickness of the critical flange 

xi

t p = thickness of a ply; or 

= thickness of thinner ply connected; or 

= thickness of a plate 

t s = thickness of a stiffener 

t t , t t1 , t t2 = design throat thickness of a weld 

t w = thickness of a web 

V b = nominal bearing capacity of a ply or a pin; or 

= nominal shear buckling capacity of a web 

V f = nominal shear capacity of a bolt or pin—strength limit state 

V sf = nominal shear capacity of a bolt—serviceability limit state 

V * = design shear force; or 

= design horizontal storey shear force at lower column end; or 

= design transverse shear force 

V * b = design bearing force on a ply at a bolt or pin location 

V * f = design shear force on a bolt or a pin—strength limit state 

V * sf = design shear force on a bolt—serviceability limit state 

V x1 , V x2 , V x3 = design shear capacity for uncoped and coped beam webs 

W u = wind load for the strength limit state 

W s = wind load for the serviceability limit state 

Z e = effective section modulus 

Z min = elastic section modulus for an angle about relevant axis normal to 

leg and perpendicular to load 


α b = compression member section constant, as defined in Para. 6.3.3 

α c = compression member slenderness reduction factor 

α m = moment modification factor for bending 

α s = slenderness reduction factor 

α v = shear buckling coefficient for a web 

β e = modifying factor to account for conditions at the far ends of beam 

members 

β m = ratio of smaller to larger bending moment at the ends of a member 

γ, γ 1 

, γ 2 

= ratios of compression member stiffness to end restraint stiffness 

used in Para. 4.6.3.3 

∆s1 = 1st order sway displacement ∆s of top relative to the bottom 

storey height 

∆s2 = 2nd order sway displacement ∆s 

δ b = moment amplification factor for a braced member 

δ m = moment amplification factor, taken as the greater of δ b and δ s 

δ s = moment amplification factor for a sway member 

λ c = elastic buckling load factor 

µ = slip factor 

φ = capacity factor 

ψ c = live load combination factor used in assessing the design load for 

strength limit state 

ψ s = short-term live load factor used in assessing the design load for 

serviceability limit state 

xii

INDEX 

Action 

combined Chapter 8 

design 3.1 

nominal 3.1 

other 3.2.2 

Amplification 

4.4.2, Appendix A 

Analysis 

assumptions for 4.3 

elastic 4.4 

plastic 4.5 

Angle 

bending 5.1.7 

compression 6.6 

Area 

effective 6.2 

gross 6.2, 7 

net Chapter 7 

Beam Chapter 5 

Bearing 

web 5.2.3 

bolt 9.2.3 

Bending Chapter 5 

biaxial Chapter 8 

Bolt 9.2 

Braced member 

4.4.2, A1 

Bracing 5.1.6 

Brittle fracture Chapter 10 


Capacity factor Table 3.1 

Column Chapter 6 

Combined actions 

Chapter 8, App B 

Compression member Chapter 6 

form factor 6.2 

section constant Table 6.2 

slenderness reduction factor Table 6.3 

effective length 6.5 

Connection Chapter 9 

minimum design action 9.1 

shear 9.4 

xiii

Corrosion 3.5.5 

Critical flange Fig. 5.1 

Deflection 3.5.2, Table 3.2 

Design Chapter 3 

Detail category Table 11 

Eccentricity 4.3.2 

Edge distance 9.2.2 

Effective length 

bending 5.1.5 

compression 6.5 

Elastic analysis 4.4.1 

Fatigue Chapter 11 

Form of construction 4.2 

rigid 4.2.1 

simple 4.2.1, 4.3.2 

Frame 4.4.2 

Hole 9.2.1 

Hollow section 

circular 5.2.2, Table 6.2 

rectangular 5.1.4.2, Table 5.1, Table 6.2 


Lateral buckling 5.1.5 

Limit state Chapter 3 

serviceability 3.5, 5, 9.2.4 

stability 3.3 

strength 3.4, 5, 6, 7, 8, 9, 9.2.3, 9.4 

Limitation 1.2, 5.1.1 

Load 3.2.1 

arrangement of live 4.3.3 

bearing stiffeners 5.2.4 

combinations 3.3 

design 3.2.1 

Load height 5.1.5 

Materials Chapter 2 

Member 4, 5, 6, 7, 8 

bending Chapter 5 

xiv

aced 4.4.2 

compression 4.4.2, 4.4.3, 6 

parallel restrained 5.1.6 

sway 4.4.2 

tension Chapter 7 

Moment amplification 

4.4.2, Appendix A 

Moment connection 4.5.1 

Moment capacity 

member 5.1.2, 5.1.4 

section 5.1.3 

slenderness reduction factor 5.1.2, 5.1.4.1, 5.1.4.2 

moment modification factor 

5.1.2, Fig. A1 

Pitch 9.2.2 

Plastic analysis 4.1, 4.5 

Restrained cross-section 5.1.5 

fully lateral 5.1.4.1 

Restrained member, parallel 5.1.6 

Restraint 

compression member 6.5.1 

full lateral 5.1.4.1, 5.1.6 

immediate lateral 5.1.5 

lateral deflection 5.1.5, 6.5.1 

lateral rotation 5.1.5 

partial 5.1.5 

torsional end 5.1.5, 5.2.4 

twist rotation 5.1.5, 5.1.6 


Second-order effect 1.1, 4.4 

Section 

angle 5.1.7 

capacity 5.1.3 

circular hollow 5.1.1 

compact 5.1.1 

non-compact 5.1.1 

rectangular hollow 5.1.4., 5.1.4.2 

Section modulus 5.1.3 

Shear capacity 

bolt 9.2.3, 9.2.5 

web 5.2.2 

xv

Shear connection capacity 9.4 

single angle cleat Table 9.4.1 

double angle cleat Table 9.4.2 

flexible end plates Table 9.4.3 

bearing pad Table 9.4.4 

angle seat Table 9.4.5 

web side plate Table 9.4.6 

Shear stress distribution Fig. 5.6 

Slenderness 

compression member 6.4, 6.5 

flexural member 5.1.4, 5.1.5, 5.1.6 

plate or section element Table 5.1, Table 6.1 

web 5.2 

Slenderness reduction factor 5.1.4.1, 5.1.4.2 

compression member 6.4, Table 6.3 

Slip 9.2.4, 3.5.4, Table 3.1 

Slip factor 9.2.4 

Steel 

grade Chapter 2 

strength Table 2.1 

type Table 2.1 

Stiffener 5.2.4 

Stress cycle Chapter 11 

Stress range Chapter 11 

Sway 4.4 


Temperature (design service) Chapter 10 

Tensile strength 2.2, 9.2.1, 9.3.2 

Tension Chapter 7 

Tension (minimum bolt) 9.2.5 

Tension capacity 

bolt 9.2.3 

section Chapter 7 

Tension member Chapter 7 

Tensioning (snug tight) 9.2.1 

Thickness 

design throat of weld 9.3.2 

effect on yield stress Table 2.1 

Triangulated structure 4.4.1, 6.5.2, 6.6 

Unrestrained cross-section 5.1.5 

xvi

Web 

design 5.2 

transversely stiffened 5.2.1 

unstiffened 5.2.1 

Weld 

butt 9.3.1 

category Table 3.1 

fillet 9.3.2 

GP (general purpose) Table 3.1 

incomplete penetration Table 9.3.1 

SP (special purpose) Table 3.1 

size 9.3.1, 9.3.2 


xvii


xviii


xix


xx

PART I 

SIMPLIFIED DESIGN RULES 

Accessed by UNSW - LIBRARY on 05 Oct 2002

2 

1 SCOPE AND GENERAL 

1.1 SCOPE 

This Handbook gives simplified rules and procedures for the design of a 

limited range of steel structures. The exclusions are given in Para. 1.2; other 

limitations to the use of the Handbook are given at the appropriate sections. 

The rules are based on and comply with Australian Standard AS 4100— 

1998. 

AS 4100 Ref. 

1.1 

The Handbook is not a comprehensive textbook; nor is it a commentary on AS 4100 except to the extent 

needed to facilitate the use of the Standard itself. Because it is a Handbook and not a Standard, the 

mandatory ‘shall’ is not used unless the rule is quoted verbatim from AS 4100, in which case it is 

identified by an asterisk in the AS 4100 Reference marking. Only AS 4100 has the authority to assert 

mandatory requirements for design. If a designer chooses to act beyond the advice offered here, it is 

necessary to ensure that such action is not beyond the mandatory limits set out in AS 4100. Any part of 

AS 4100 may be used and the outcome substituted safely in a procedure based on this Handbook. While a 

design determined with this Handbook complies with AS 4100, the reverse is not necessarily so. 

The rules in this Handbook are intended to be self-sufficient for application in the design of a wide range 

of common structures which do not need or justify the refined methods of a higher tier design. Such 

applications are found in domestic structures, in low-rise buildings, in fully braced situations and in 

industrial structures where the designer is confident that second-order effects can be ignored. 

The main objective of this Handbook is simplicity, which is achieved by restricting the ranges of crosssections 

and of materials to which the rules apply; members and materials produced in accordance with 

Australian Standards mostly fall inside these restrictions, and specific exclusions, such as members with 

slender elements, are set down clearly in the rules. 

Simplicity is bought at a price. Correspondingly, the effort incurred in using the higher tiers of AS 4100 

must be expected to offer some gain and, therefore, designs prepared by using this Handbook will 

frequently be able to be refined by using AS 4100. 

Throughout the Handbook, the rules are given in boxes in the text in order to make them easy to 

find and read. The appropriate cross-referencing to AS 4100 is given in a marginal box adjacent to 

the rule, and commentary is provided immediately under the text of the rule. This page 

demonstrates such a format. The rules given in the boxes either comply with or are conservative 

with respect to AS 4100. However, it should be noted that some of the simple approximations 

provided in the commentary are intended for preliminary design only, and are not always 

conservative. 


A lower tier design method differs from a higher tier one in the way in which it assures the reliability of 

the structure being designed. Higher tier methods are designed to use more sophisticated models of 

structural behaviour so that the outcome is a structure which can be more severely loaded but still have 

acceptable reliability. In Chapter 4, a more detailed commentary is given on restricting lower tier methods 

to structures for which second-order analysis is not necessary. 

An example of the limitations of a lower tier approach is to be found in the way this Handbook handles 

yield stress. Advice is given in some rules for a specific yield stress of 300 MPa only. By contrast, 

AS 4100 gives the engineers the flexibility of selecting a value of yield stress to use in an algebraic 

expression. A second example is the limitations of the advice on fracture-sensitive structures.

3 

1.2 EXCLUSIONS 

AS 4100 Ref. 

This Handbook is not intended for use outside the limits given in the 

text, nor is it intended for: 

(a) Lattice towers fabricated from angle sections* 

(b) Cranes and crane beams† 

(c) 

(d) 

(e) 

(f) 

Buildings for which analysis for earthquake forces is required by 

AS 1170.4‡ 

Vehicular bridges 

Arches 

Tall, wide, multistorey frames more than 10 storeys high and 

5 bays wide 

(g) Structures fabricated from unidentified materials§ 

(h) Non-standard fabricated sections 

(i) Fasteners other than those specified in Para. 2.3 of this Handbook 

(j) Other structures and materials listed in Clause 1.1.1 of AS 4100, 

viz. 

• Steel elements less than 3 mm thick, with the exception of 

sections complying with AS 1163 

• Steel members for which the design yield stress exceeds 

450 MPa 

• Cold-formed members, other than those complying with 

AS 1163, which must be designed in accordance with 

AS/NZS 4600 

• Composite steel-concrete members, which must be designed 

in accordance with AS 2327. 

* Refer to AS 3995 

† Refer to AS 1418.1 and AS 3500 respectively 

‡ Refer to AS 1170.4 

§ Refer to Clause 2.2.3 of AS 4100 


4 

2 MATERIALS 

2.1 AUSTRALIAN STANDARDS FOR STEEL 

Before fabrication, all structural steel coming within the scope of 

this Handbook is required to comply with the following Australian 

Standards: 

AS 4100 Ref. 

2.2.1 

AS 1163 

AS/NZS 3678 

AS/NZS 3679 

Structural steel hollow sections 

Structural steel—Hot-rolled plates, floor plates and 

slabs 

Structural steel 

Part 1: Hot-rolled bars and sections 

Part 2: Welded I sections 

2.2 YIELD STRESS AND TENSILE STRENGTH OF 

STEEL 

The yield stress fy and tensile strength fu used in design may be 

obtained from Table 2.1. 

AS 4100 Ref. 

2.1 

2.3 STEEL BOLTS, NUTS AND WASHERS 


Steel bolts, nuts and washers complying with AS/NZS 1111 ISO 

metric hexagon commercial bolts and screws and AS/NZS 1112 

ISO metric hexagon nuts, including thin nuts, slotted nuts and castle 

nuts, and AS/NZS 1252, High strength steel bolts with associated 

nuts and washers for structural engineering, are suitable for 

construction based on this Handbook. 

2.4 WELDS 

Welds complying with AS/NZS 1554.1 Structural Steel welding, 

Part 1: Welding of steel structures are suitable for construction 

based on this Handbook. 

AS 4100 Ref. 

2.3.1 

AS 4100 Ref. 

2.3.3

5 

Table 2.1 Strengths of steel complying with AS 1163, 

AS/NZS 3678 and AS/NZS 3679.1 

Form 


grade 

Thickness 

of 

material (t) 

Yield 

stress 

fy 

Tensile 

strength 

fu 


Standard 

(mm) (MPa) (MPa) 

Rolled 

sections 

300 or 

300 LO or 

300 L15 

350 or 

350 LO or 

350 L15 

t ≤ 11 

11 < t ≤ 17 

17 ≤ t 

t ≤ 11 

11 < t ≤ 40 

40 ≤ t 

320 

300 

280 

360 

340 

330 

440 

440 

440 

480 

480 

480 

AS/NZS 3679.1 

Structural Steel— 

Part 1: Hot-rolled 

bars and sections 

250 only 12 < t ≤ 50 

50 < t ≤ 80 

80 < t ≤150 

250 

240 

230 

410 

410 

410 

250 L15 only 12 < t ≤ 50 

50 < t ≤ 150 

250 

240 

410 

410 

Plate 

300 or 

300 L15 

350 or 

350 L15 

8 < t ≤ 12 

12 < t ≤ 20 

20 < t ≤ 150 

t ≤ 12 

12 < t ≤ 20 

20 < t ≤ 80 

80 < t ≤ 150 

310 

300 

280 

360 

350 

340 

330 

430 

430 

430 

450 

450 

450 

450 

AS/NZS 3678 

Structural steel— 

Hot-rolled plates, 

floor plates and 

slabs 

400 or 

400 L15 

t ≤ 12 

12 < t ≤ 20 

20 < t ≤ 50 

400 

380 

360 

480 

480 

480 


Hollow 

sections 

C250 or 

C250 LO 

C350 or 

C350 LO 

C450 or 

C450LO 

All 

All 

All 

All 

All 

All 

250 320 

350 430 

450 500 

AS 1163 

Structural steel 

hollow sections

6 

3 DESIGN 

3.1 LIMIT STATES DESIGN PRINCIPLES 

Limit states design requires that structures, including all members and 

connections, be designed so that the relevant design resistances are not 

less than the design actions arising from the design loadings for all 

limit states. 

AS 4100 Ref. 

3.1 

The aim of structural design is to provide a structure which is stable, has adequate strength, is serviceable 

and durable, and which satisfies other objectives such as economy and ease of construction. This aim is 

achieved by using the ‘Limit States Design’ method to ensure that the limit states of stability, strength and 

serviceability are satisfied; a structure is considered to be unacceptable if it does not satisfy each of these 

limit states. Conditions for which limit states have been selected take into account the statistical variations 

which occur in both member behaviour and material properties as well as the variations in the loads and 

actions applied to the structure and the imperfections of modelling of behaviour. 

A structure is stable if it does not overturn, tilt or slide throughout its intended life. A structure has 

adequate strength and is serviceable if the probabilities of structural failure and of loss of serviceability 

throughout its intended life are acceptably low. A structure is durable if it withstands the expected wear 

and deterioration throughout its intended life without the need for undue maintenance. 

For strength limit states, the design actions S * , such as bending moments, shear or axial forces, are 

obtained from the strength combination of dead, live, wind and other loads as specified in AS 1170.1, 

AS 1170.2, AS 1170.3 and AS 1170.4. The nominal loads provided in these Standards are multiplied by 

the appropriate load factors to obtain the design loads (the load factors are generally greater than 1.0). 

The total design capacity is φRu and is determined in accordance with Para. 3.4. 

For serviceability limit states, the design action, such as deflection, sway or bolt slip, is obtained from an 

analysis of the structure or the member using the loads and load combinations for the appropriate 

serviceability limit states. (The load factors for serviceability are generally equal to or less than 1.0.) The 

computation may be carried out without amplification for second order effects (see Section 4). The total 

design resistances in this case are the serviceability limits such as those given in Table 3.2. 

For stability limit states, the design criteria incorporating the required load combination are specified in 

AS 1170.1. The total design actions S* are obtained from the components of the loads tending to cause 

instability. The total design resistance φR is calculated as 0.8 times the part of the dead load tending to 

resist instability plus the design capacity φRu of any element contributing toward resisting instability. 


7 

3.2 LOADS AND ACTIONS 

3.2.1 Loads 

The design of a structure should account for all potential loads arising 

from its operation. These may include construction loads, the 

appropriate dead, live, wind, earthquake and snow loads specified in 

AS 1170, crane loads in AS 1418, lift loads in AS 1735 and platform, 

walkway, stairway and ladder loads in AS 1657. The design load 

combinations are those specified in AS 1170.1 for the appropriate 

limit state. 

AS 4100 Ref. 

3.2.1 

3.2.2 Other actions 

There are other actions which may need to be considered because 

they may significantly affect the stability, strength or serviceability of 

the structure, including the following: 

(a) Foundation movements 

(b) 

(c) 

(d) 

Temperature changes and gradients 

Axial shortening 

Dynamic effects 

AS 4100 Ref. 

3.2.1 

3.2.2 


8 

3.3 LOAD COMBINATIONS 

Load combinations can be obtained from AS 1170.1. For the cases 

involving dead, G, live, Q, and wind loadings, Wu, Ws, the 

requirements can be expressed by the following: 

Load Combinations for Strength Limit State 

(a) 1.25G + 1.5Q 

(b) 1.25G + Wu + ψCq 

(c) 0.8G + 1.5Q 

(d) 0.8G + Wu 

where ψc = 0.0 for non-trafficable roofs 

ψc = 0.6 for storage structures 

ψc = 0.4 for all other situations 

AS 4100 Ref. 

Load Combinations for Serviceability Limit State 

(a) Ws 

(b) Q 

(c) G + ψsQ 

ψs = 1.0 for storage structures 

ψs = 0.7 for all other structures 

Design Criteria for Stability Limit State 

(a) 

(b) 

1.25G + 1.5Q < 0.8G R + φR u 

1.25G + ψcQ + Wu < 0.8G R + φR u 

G R is the part of the dead load tending to resist instability. G, Q, Wu 

are parts of the dead, live and wind loads that tend to cause 

instability. 


For the serviceability limit state, the serviceability loads should be appropriate for the serviceability 

condition. For steel structures, there should not be any long-term structural serviceability problem. The 

serviceability loads and load combinations suggested here are the normal load combinations to be 

checked for steel structures, but do not cover all the possibilities given in AS 1170.1 (e.g. long-term 

effects such as creep). This should serve to remind designers that the load combinations need to be 

selected depending on the circumstances.

9 

3.4 STRENGTH LIMIT STATE 

AS 4100 Ref. 

The structure and its components are designed for the strength limit 

state by ensuring that all members and connections are proportioned 

so that the design capacity φRu is not less than the design action S* 

3.4 

S * ≤ φRu 

Specific values of φRu are given in Sections 5 to 9, as appropriate. A 

summary of the φ values is found in Table 3.1. 

DESIGN ACTIONS 

The design actions S * are the actions such as axial force, shear force and bending moment which are 

produced by the design loads. Separate design actions are calculated for each of the limit states. 

DESIGN CAPACITIES 

The design capacity φRu is obtained from the nominal capacity of the structure or member Ru modified 

by a capacity factor φ. The capacity factor φ is always less than unity and reflects the variability and 

uncertainty of material properties and member behaviour. Significant variation in the value of the 

capacity factors is therefore to be expected. In this Handbook the capacity factor is incorporated 

numerically in the design rules as printed. 

It is important to recognise that the limit states design method has some very significant differences from 

the allowable stress method of design which was used in AS 1250. In the allowable stress method, an 

elastic analysis is used to determine the design actions under so-called working load conditions, these 

being roughly comparable to the serviceability loads of the limit state design method. The design actions 

are then used with allowable stresses which have been set to provide a margin of safety which is intended 

to take account of both overloading and uncertainties of member behaviour and material variations. 

This approach is in direct contrast to the limit states design method where load factors are applied to loads 

to allow for overloading and load variability; a separate allowance is made to the member behaviour 

through the use of a capacity reduction factor. 

It is of utmost importance that the distinction between the two methods is recognised and that the loads, 

load combinations and design capacities are appropriate to the method used. 


10 

Table 3.1 Capacity factors (φ) for strength limit states 

(These capacity factors have been incorporated in the design capacity 

formulae in this Handbook, and are provided here for information only.) 

Design capacity for 

Capacity factor 

φ 

Relevant section 

of AS 4100 

Structural members and connection 

components other than a bolt, pin or 

weld 

0.90 5 to 9 

Bolted and pinned connections 

— ply in bearing 

— friction-grip with slip 

— all other conditions 

0.90 

0.70 

0.80 

9.3 to 9.5 

3.5.5 

Welded connections 

— complete penetration butt weld 

— longitudinal fillet weld in RHS 

(t < 3 mm) 

— all other welds 

SP* 

0.90 

0.70 

0.80 

GP* 

0.60 

- 

0.60 

9.7.1.3 

9.7.2.7 

9.7.3.10 

* SP — special purpose weld 

GP — general purpose weld 

Refer to AS/NZS 1554.1 for definition of SP and GP and for other requirements. 


11 

3.5 SERVICEABILITY LIMIT STATE 

3.5.1 General 

The serviceability limit states to be considered are deflection, 

vibration, bolt slip and corrosion. The loads and actions are to be 

determined in accordance with Para. 3.2. 

AS 4100 Ref. 

3.5.1 

3.5.2 Deflection limits 

Deflections may be determined by the elastic analysis method. The 

deflection limits are the responsibility of the designer and need to be 

appropriate to the structure and its intended use, the nature of the 

loading, and the elements supported by it. Guidance on some 

deflection limits can be gained from Table 3.2. These may be midspan 

deflections for beams, sway deflections for columns, or the 

relative horizontal deflection between adjacent frames at the eaves 

level of industrial buildings. 

AS 4100 Ref. 

App. B 

Deflection limits of Table 3.2 are not mandatory in accordance with AS 4100. The footnotes to 

Table 3.2 give some guide as to the levels of deflection at which different forms of serviceability failure 

might occur. In some instances more conservative values may need to be adopted. 

For guidance on the deflection limit below which moment amplification may be ignored, refer to 

comments in Para. 4.4.2. 

3.5.3 Vibration of beams 

AS 4100 Ref. 

Beams which support floors or machinery shall be checked to ensure 

that the vibrations induced by machinery, or vehicular or pedestrian 

traffic, do not adversely affect the serviceability of the structure. 

Where there is a likelihood of a structure being subjected to 

vibration from causes such as wind forces or machinery, measures 

shall be taken to prevent discomfort or alarm, damage to the 

structure, or interference with its proper function. 

3.5.4* 


AS 2670.2 gives guidance for the evaluation of human exposure to whole-body vibrations of the type 

likely to be transmitted by structures. 

An asterisk (*) on the AS 4100 reference indicates that the paragraph is a direct quotation from AS 4100.

12 

3.5.4 Slip in bolted connections 

Chapter 9 assumes that where slip in a bolted connection under the 

serviceability design loads is to be prevented, the selected fasteners are 

of grade 8.8/TF. 

3.5.5 Corrosion protection 

Where steelwork in a structure is to be exposed to a corrosive 

environment, the steelwork needs to be given protection against 

corrosion. Refer to AS 4100 Appendix C and AS/NZS 2312, Guide to 

the protection of iron and steel against exterior atmospheric 

corrosion. 

AS 4100 Ref. 

3.5.5 

AS 4100 Ref. 

3.5.6 

App. C 


13 

Table 3.2 Suggested deflection limits from Appendix B of AS 4100 

Type of member Deflection to be considered Deflection limit 

l 

500 

Beam supporting 

masonry partitions 

All beams 

Building clad in flexible 

sheeting without gantry 

cranes and without 

internal partitions against 

external walls 

Deflection which occurs after 

the attachment of partitions 

Total deflection 

Relative horizontal deflection 

between adjacent frames at 

eaves level of industrial 

building due to wind load 

where provision is made to 

minimize the effect of 

movement, otherwise 

l 

1000 

l 

250 

h s 

150 

Building with masonry 

walls supported by 

steelwork 

Relative horizontal deflection 

between adjacent frames at 

eaves level of industrial 

building due to wind load 

h s 

240 

Notes 

1 l/250 limit for all beams may not safeguard against ponding or dynamic response of floors or 

problems caused by end rotation on simply supported beams. 

2 l = span of beam — for cantilevers the value of l to be used in Table 3.2 is twice the cantilever 

span. 

3 h s = storey height. 

4 The following behaviour might be expected at the indicated level of deflection: 

Typical behaviour 

Deflection 

Cracking of brickwork l/1000 not visible 

Cracking of brittle partition wall h s /500 not visible 


General architectural damage, cracking of 

reinforced walls 

Damage to ceiling and flooring, cladding 

leakage 

Damage to lightweight partitions, 

display windows, finishes 

Impaired operations of movable componentsdoors, 

windows sliding partitions 

l/300, h s /300 

l/200 to l/300 

h s /200 to h s /300 

l/100 to l/200 

h s /100 to h s /200 

visible 

visible 

visible

14 

4 METHODS OF STRUCTURAL ANALYSIS 

4.1 METHODS OF DETERMINING DESIGN ACTIONS 

The design actions in a structure and its members and connections 

caused by the design loads may be determined by structural analysis 

using the assumptions of Paragraphs 4.2 and 4.3 and one of the 

methods of 

(a) 

(b) 

Elastic analysis, in accordance with Para. 4.4 (for strength and 

serviceability limit states), 

Plastic analysis, in accordance with Para. 4.5 (for strength limit 

state). 

AS 4100 Ref. 

4.1 

4.2 FORMS OF CONSTRUCTION ASSUMED FOR ANALYSIS 

4.2.1 General 

Structures may be analysed by assuming that both shear and moment 

are transferred across a connection (rigid construction) or only shear 

is transferred across a connection (simple construction). 

AS 4100 Ref. 

4.2 

For design under the simplified conditions applicable to this Handbook, semi-rigid construction is not 

appropriate. 

4.2.2 Design of connections 

The design of connections should be consistent with the assumptions 

made for structural analysis in Para 4.2.1. Connections in rigid 

construction need to be at least as stiff as the more flexible of the two 

members being connected and to be designed for the maximum 

expected loads at the connection. 

Connections in simple construction should be capable of transferring 

the shear forces acting at an eccentricity appropriate to the 

connection detailing. The connection should be capable of deforming 

to provide the required rotation at the connection, without developing 

a significant restraining bending moment. 

AS 4100 Ref. 

4.2.5 

9.1.2 


15 

4.3 ASSUMPTIONS FOR ANALYSIS 

4.3.1 Arrangements of live loads for buildings 

For building structures, the arrangements of live loads considered in 

the analysis shall include at least the following: 

(a) 

(b) 

(c) 

Where the loading pattern is fixed, the arrangement concerned. 

Where the nominal live load (Q) is variable and not greater 

than three-quarters of the nominal dead load (G), the design 

live load (Q * ) on all spans. 

Where the nominal live load (Q) is variable and exceeds threequarters 

of the nominal dead load (G), arrangements for the 

floor under consideration consisting of 

AS 4100 Ref. 

4.3.3 * 

(i) 

(ii) 

(iii) 

the design live load (Q * ) on alternate spans; 

the design live load (Q * ) on two adjacent spans; and 

the design live load (Q * ) on all spans. 

The term ‘nominal’ refers to the unfactored values of the loads as given in AS 1170.1 

The arrangement under (c) above assumes approximately equal spans for beams. 

4.3.2 Simple construction 

Bending members may be assumed to have their ends connected for 

shear only and to be free to rotate. In triangulated structures, axial 

forces may be determined by assuming that all members are pin 

connected. 

A beam reaction or a similar load on a column shall be taken as acting 

at a minimum distance of 100 mm from the face of the column 

towards the span or at the centre of bearing, whichever gives the 

greater eccentricity, except that for a column cap, the load shall be 

taken as acting at the face of the column, or the edge of the packing if 

used, towards the span. 

AS 4100 Ref. 

4.3.4* 

. 


For a continuous column, the design bending moment (M * ) due to 

eccentricity of loading at any one floor or horizontal fame level shall 

be taken as: 

(a) Ineffective at the floor or frame levels above and below that floor; 

and 

(b) Divided between the column lengths above and below that floor or 

frame level in proportion to the values of I/l of the column lengths.

16 

4.4 ELASTIC ANALYSIS 

4.4.1 General 

The method of elastic analysis can be used generally. In a first order 

analysis, the effects of changes in the geometry on the distribution and 

magnitude of design actions are not taken into account; the changes in 

the effective stiffness of members due to axial force are neglected. The 

effects of these changes on the first order bending moments are allowed 

for by using one of the methods of moment amplification of 4.4.2 or 

Appendix A, as appropriate. When the moment amplification factor is 

greater than 1.4, then a second order analysis is required by AS 4100. 

AS 4100 Ref. 

4.4.2.1 

For design under the simplified conditions applicable to this Handbook, the determination of design 

actions may be made by the use of a first order analysis for both the general frame analysis and for 

member design. 

The types of structural systems for which first order frame analysis may be used to determine design 

action S* without any corrections for second order effects, include: 

(a) 

(b) 

triangulated frames in which the member forces are predominantly axial, i.e. where lateral 

forces acting on the compression chord are negligible. 

structures in which there are negligible axial compressive forces. 

Structural systems for which a first order frame analysis may need to be modified to account for second 

order effects in order to obtain design actions S* include: 

(a) braced rigidly-jointed frames in which sway is negligible but with: 

(i) high axial force; and 

(ii) moments due to lateral loads on members. (Refer Figure 4.1) 

(b) unbraced rigidly-jointed frames with: 

(ii) high axial forces; and 

(ii) moments due to sway-displacement. (Refer Fig. 4.2) 


17 

N* N* 

H* 

Deflections 

Bending moments 

(a) First order behaviour 

N* N* 

H* 

Amplified deflections 

Amplified bending moments 

(b) Second order behaviour 


Note: The symbols used in the above illustrations are defined solely by their use in these 

figures. 

FIGURE 4.1 BRACED SYSTEMS

18 

H* 

N* N* 

∆s 1 

V s * . h s 

V s * . h s 

V s * = H* /2 

h s 

V s * 

V s * 

Deflections 

Bending moments 

(a) First order behaviour 

H* 

∆s 

N* 2 N* 

V s * . h s + N*. ∆s 2 

V s * V s * 

Amplified deflections 

Amplified bending moments 

(b) Second order behaviour 


Note: The symbols used in the above illustrations are defined solely by their use in these 

figures. 

FIGURE 4.2 UNBRACED SYSTEM WITH SWAY

19 

4.4.2 Moment amplification 

For a member with a design axial compressive force N* and a calculated 

design bending moment M * m as determined by the first order analysis, 

the design bending moment M* may be taken as: 

AS 4100 Ref. 

4.4.2.2 

M 

* = 11 . M * 

m 

without any further analysis for amplification provided that the 

following conditions apply: 

(i) 

For both braced and sway members of grade 300 steel, 

l 

e 

/ r ≤ 

N 

* 

27 

/ 0.9 

N 

s 

≤ 300 

where l e /r is the member slenderness about the same axis as that about 

which the design bending moment is applied and N s is the nominal 

compressive axial section capacity of the member (see Para. 6.2). For 

steel grades other than 300 the above limit is changed by a factor equal 

to 300 / f . 

(ii) 

y 

For sway members in rectangular frames only 

∆ s ∑ F 

≤ 01 . h 

hs 

∑ Fv 

where ∆ s is the horizontal displacement of the top relative to the bottom 

of member, h s is the height of the member, and ∑ Fh 

is the ratio of the 

∑ Fv 

total horizontal loads to the vertical loads above the storey. 

If the above limits are not satisfied, a moment amplification analysis in 

accordance with AS 4100 is recommended and is explained in 

Appendix A. 


Moment amplification can be effectively neglected (M 

* ≤1. 

01 M * 

m ) if the limits corresponding to the 

conditions above are: 

9 

le 

/ r ≤ and ∆ s ∑ F 

≤ 

h 

001 . 

* 

N / 0.9N 

hs 

∑ Fv 

s 

For preliminary design, moment amplification in a portal frame may be neglected. For a more careful 

assessment refer to Appendix A (Para. A3).

20 

4.5 PLASTIC ANALYSIS 

4.5.1 Limitation 

(a) 

(b) 

(c) 

For the use of this Handbook, plastic analysis may be applied to 

the design of beams and portal frames only if the axial forces in 

the members are less than 5% of their design axial capacities. 

Plastic analysis may be used only for members of hot-formed, 

doubly symmetric, compact I section with minimum specified 

yield stress not exceeding 450 MPa and complying with 

AS/NZS 3678 or AS/NZS 3679.1. 

All moment connections are limited to full strength moment 

connections. 

AS 4100 Ref. 

4.5.2 

4.5.2 Analysis 

(a) 

(b) 

Design actions may be determined using a rigid plastic 

analysis. 

The moment capacity of a connection may not be less than that 

of the members being connected. 

AS 4100 Ref. 

4.5.3 

For the type of simplified design applicable to this Handbook, it is preferable to have the hinges in 

members for maximum rotation capacity rather than in the connections. 

When plastic design is used, it is essential to ensure the members are fully restrained (as defined in 5.1.5). 

In addition, for plastic design of beams, the shear connections at the ends of a beam require adequate 

rotational capacity so that a plastic hinge can form elsewhere in the beam. This requirement is to be 

achieved without reducing the connection shear capacity. 


21 

5 MEMBERS SUBJECT TO BENDING 

The procedure for checking of members subject to bending is as follows: 

(a) 

(b) 

(c) 

Establish the bending moment diagram, the conditions of supports and lateral restraints (see 

Para. 5.1.5). 

For long span beams (say span exceeding 25 times beam depth), first check the serviceability 

limit of deflection; although the deflection limits are not mandatory according to AS 4100, it 

will often be the controlling factor for long span beams. 

For other beams, first check the strength limit states: 

(i) 

Member bending capacity 

• Calculate the section capacity (Para. 5.1.3, Design aids D3-D6) to provide a basic load 

capacity irrespective of length. 

• Calculate the member capacity (Para 5.1.4, Design aids D7-D24), which allows for 

member length. 

• Check the adequacy of the restraining elements (Para 5.1.6). 

(ii) Shear capacity (Para 5.2.2, Design aids D3-D6). 

(iii) Check the bearing condition at the support (Para 5.2.3) and if necessary provide load 

bearing stiffeners (Para 5.2.4, Design aids D3-D6). 

5.1 DESIGN FOR BENDING MOMENT 

5.1.1 General 

(a) 

Classification of sections 

Steel sections are classified on the basis of the maximum widththickness 

ratios of their compressive elements as specified in 

Table 5.1 

Section in bending with: 

• maximum (b/t) less than the plastic limit are COMPACT sections 

• maximum(b/t) less than the yield limit but more than the plastic 

limit are NON-COMPACT sections 

• maximum(b/t) more than the yield limit are SLENDER sections 

AS 4100 Ref. 

5.2.2 

5.2.3 

5.2.4 

5.2.5 


Limiting b/t is necessary to avoid local buckling problems which depend on stress levels, plate geometry 

and boundary conditions.

22 

(b) Limitations 

The rules in this section are applicable only for 

• SECTION TYPES: Compact or non-compact sections with single 

or double symmetry such as Australian standard universal and 

welded beams and columns, channels, rectangular and circular 

hollow sections or angles. 

• DESIGN METHODS: Elastic design method generally and 

plastic design for beams and for beam-columns where the axial 

load is limited to 5% of the design axial capacity. The type of 

sections suitable for plastic design requires the width-thickness 

ratios of both the flange and web components be within the 

plastic limit of Table 5.1. 

AS 4100 Ref. 

5 

4.5.2 

5.10.6 

Table 5.1 Limiting width-thickness ratios for elements in flexural compression 

Description of element 

Flanges of universal sections, 

tee sections and channels 

(major axis bending) 

Flanges of welded sections 

(major axis bending) 

Flanges of universal sections 

and channels 

(minor axis bending) 

Flanges of welded sections 

(minor axis bending) 

(b/t)lim 

Plastic limit 

Yield limit 

300 350 400 300 350 400 

8 7.5 14 13 

7 6 12 11 

8 7.5 22 21 

7 6 20 17 

Flanges of RHS 

Grade 450: 

25 

22 

34 

Angles 8 7.5 22 21 

Stems of tees 8 7.5 22 21 

Grade 450: 

30 

Webs 74 69 65 105 97 91 

Circular hollow sections 

(b = do) 

Grade 250: 

42 

30 

Grade 250: 

120 

85 


Table 5.1 is an interpretation of Table 5.2 of AS 4100 as applicable to commonly used types of sections 

using the grade designation as the yield stress. 

If a section is compact, the effective section properties are the same as the gross section properties. If the 

section is non-compact or slender, the effective section properties are less than the gross section 

properties. Note that the minimum radius of gyration ry is based on GROSS section geometry.

23 

5.1.2 Design requirements 

When a member is subject to a design bending moment M * about the 

section principal axis it is recommended that: 

M 

* 

≤ 0.9 Mb 

( = 0.9α 

) 

s M s 

AS 4100 Ref. 

5.1 

5.2 

5.6 

where 

Mb = 

Ms = 

i.e. 

M 

* ≤ 0.9 α s 

f y Ze 

the nominal capacity of the member in bending 

the nominal capacity of the section in bending about the 

relevant principal axis as specified in 5.1.3 

αs = slenderness reduction factor (as specified in 5.1.4 

and 5.1.5) which never exceeds 1.0. 

This is a simplified form of Equation 5.6.1.1(1) of AS 4100 with αm = 1.0, which is conservative for all 

situations. Further increase in the design moment capacity for a member lightly restrained is possible by 

introducing a factor αm calculated as follows: 

where 

* 

M m 

M * * 

2 ,M 4 

* 

M 3 

α m 

= 

* 

17 . Mm 

* 

2 2 * 

+ 3 2 * 

+ 4 2 

( M ) ( M ) ( M ) 

= maximum design bending moment in the segment 

≤ 25 . 

= design bending moments at the quarter points of the segment 

= design bending moment at the midpoint of the segment 

Note that (αs α m) must never exceed 1.0. 


24 

5.1.3 Nominal section capacity 

AS 4100 Ref. 

The nominal capacity of a section in bending is given by 

Ms = fy Z e 

where 

Ze is the effective section modulus and is given in BHP Structural 

Products Handbook or similar 

Deduction for holes in the computation of the effective section 

modulus is required by AS 4100 when the hole area exceeds the 

following percentages of either of the flange areas: 

5.2.3 

5.2.4 

5.2.6 

Grade 250 300 350 400 

% of hole areas 25 15 11 2 

For standard types of sections, refer to the supplier's catalogues for section classification and properties, 

e.g. 

BHP Hot Rolled and Structural Steel Products 1998 edition; 

BHP Structural and Pipeline Products – DuraGal design capacity tables: 

For steel hollow sections, June 1996. 

For structural steel angles, channels and flats, July 1997. 

For fabricated sections, refer to AS 4100 for the computation of Ze. 

5.1.4 Nominal member capacity 

AS 4100 Ref. 

The nominal capacity of a member in bending is given by 

5.6.1 

Mb = αs M s 

Where αs is a slenderness reduction factor and is given in 

Para. 5.1.4.1 and Para. 5.1.4.2. and never exceeds 1.0. 

Refer to comments on Para. 5.1.2. 


25 

5.1.4.1 Slenderness reduction factor for members with full lateral restraints 

AS 4100 Ref. 

The slenderness reduction factor αs has the value of 1.0 for: 5.1 

• A member bending about its minor principal axis 5.3 

• A member with the compression flange continuously restrained 

against lateral movement 

• A member with an effective length le which does not exceed the 

limit described below (for determination of le see 5.1.5). 5.3.2.4 

Type of section 

Limiting slenderness ratio 

(le/ry) 

I section, 300 grade 27 

Channel section, 300 grade 18 

Rectangular hollow section, 

⎛ b f 

350 grade ⎟ ⎞ 

214 

⎜ 

⎝ bw 

⎠ 

Rectangular hollow section, 

⎛ b 

f 

450 grade ⎟ ⎞ 

214 ⎜ 

⎝ bw 

⎠ 

⎛ b 

⎜ 

⎝ b 

f 

w 

⎞ 

⎟ is the ratio of width to depth of the rectangular hollow section. 

⎠ 

For the design of restraining elements refer to Para. 5.1.6. 


26 

5.1.4.2 Slenderness reduction factor for members without full lateral restraints 

AS 4100 Ref. 

The slenderness reduction factor for members without full lateral 5.6.1.1(a) 

restraint, αs, is given by: 

α s 

⎧ 

⎪ 

= 0.6⎨ 

⎪⎩ 

⎡⎛ 

⎢ 

⎜ 

⎢⎣ 

⎝ 

M s 

M o 

⎞ 2 

⎟ 

⎠ 

⎤ ⎛ M ⎞⎫ 

⎪ 

+ 3 − 

⎜ s 

⎥ 

⎟⎬ 

⎥⎦ 

⎝ M o ⎠⎪⎭ 

with 

M o = 

π 

2 

EI y 

l 

2 e 

⎡ ⎛ ⎞ 

⎥ ⎥ ⎤ 

⎢ ⎜π 

2 

GJ + 

EIw ⎟ 

⎢ ⎜ 2 ⎟ 

⎣ ⎝ l e ⎠⎦ 

For rectangular hollow sections I w = 0. 

The design moment capacities for beams without full lateral restraints are provided in the Design aids D7- 

D24. 

For preliminary design of beams, the following simple approximations for α S may be useful (but not 

always conservative): 

For I sections— 

assume α S is 1.0 up to l e /r y = 25, then varies linearly to 0.5 at l e /r y = 120. 

For channel sections— 


For rectangular hollow sections— 



27 

5.1.5 Effective length l e of beams for lateral buckling 

In the design of beams, one of the most important steps is the 

assessment of the relevant restraints and their location. The prime 

requirement is that the overall stability of the member must be 

maintained, i.e. the rigid body rotation of the cross-section must be 

prevented for at least one cross-section along the beam or cantilever 

length. 

AS 4100 Ref. 

5.4 

5.6.3 

Critical flange The critical flange at any cross-section is the flange 

which, in the absence of any restraint at that section, would deflect 

most during buckling. The critical flange at any section of a segment 

restrained at both ends is the compression flange. 

The member effective length for lateral buckling depends on the type 

of the rotational and lateral restraints on the member. 

y 

x 

z 

Lateral restraint is the restraint of movement of the critical flange in 

the direction of the x axis. 

Twist restraint is the restraint of rotation of the section about the z axis. 

Lateral rotational restraint is the restraint of rotation of the critical 

flange about the y axis (see Fig. 5.1(c)). 

A section is fully restrained if either— 

(a) the critical flange is laterally restrained and the section is fully or 

partially restrained against twisting; or 


(b) the non-critical flange is laterally restrained and the section is fully 

restrained against twisting (see Fig. 5.1(a)). 

A section is partially restrained if the non-critical flange is laterally 

restrained and the section is partially restrained against twisting (see 

Fig. 5.1(b)).

28 

5.1.5 Effective length l e of beams for lateral buckling (continued) 

AS 4100 Ref. 

The general procedure for determining effective length le for lateral 

buckling is as follows: 

5.4 

5.6.3 

Classify the type of restraints for each end of the beam segments under 

consideration as fully restrained, partially restrained or laterally 

restrained as shown in Figure 5.1(a) and (b). 

Effective length le for lateral buckling is given by: 

le = kt kl kr l 

Twist restraint factor kt is to be taken as 1.0 unless the segment has one 

or both ends partially restrained, in which case kt is greater than 1.0. 

For universal beams or columns with span/depth ratios greater than 6, 

it is conservative to assume: 

For one end partially restrained kt = 1.1 

For both ends partially restrained kt = 1.2 

Load height factor kl is to be taken as 1.0 unless the load is on the top 

flange and free to move laterally and 

One end unrestrained kl = 2.0 

Both ends restrained kl = 1.4 

Lateral rotation restraint factors kr are to be taken as 1.0 unless it is a 

segment with each end fully or partially restrained and: 

One end with lateral rotation restraint k = 0.85 

Both ends with lateral rotation restraint kr = 0.70 

For beams and cantilevers with restraints at both ends, the effective length for lateral buckling is given in 

Fig. 5.2 for cases in which the loads are applied at the shear centres of the sections. 

Fig. 5.3 gives further examples of types of restraints occurring in practice. These examples have been 

obtained from Steel Designers Handbook by Gorenc and Tinyou. 


29 

Web stiffener 

C 

C 

Flexible 

Flexible 

Flybrace 

C 

C 

Stiff 

Web stiffener 

C 

Stiff 

Flybrace 

LEGEND 

= Pin connection 

= Moment connection 

C = Critical flange 

(a) Fully restrained cross sections 

C 

C 

Flexible 

C 

Flexible 

Web stiffener 

Flybrace 

(b) Partially restrained cross sections 

z 

x 

Rotationally 

restrained 

flange 

Buckling shape of flange 

z 

x 

Rotationally 

unrestrained 

flange 

Buckling shape of flange 


(c) Rotationally restrained and unrestrained flanges 

FIGURE 5.1 DEFINITIONS OF FULLY, PARTIALLY AND ROTATIONALLY 

RESTRAINED CROSS-SECTIONS

30 

or 

(a) Continuous lateral restraint l e = 0 

l 

(b) Fully restrained ends without intermediate restraints l e = l 

l 

( >6) 

d 

l 

(c) Partially restrained ends without intermediate restraints l e = 1.2 l 

B 

C 

Restraining beam 

A 

D 

l 

( 

2 

>6) 

d 


l 1 l r l 2 

Segment AB l e = l 1 Segment BC l e = l r Segment CD l e = 1.1 l 2 

(d) Intermediate lateral restraints 

FIGURE 5.2 ILLUSTRATIONS OF EFFECTIVE LENGTHS 

FOR LATERAL BUCKLING

31 

Load bearing stiffeners 

to AS 4100, clause 5.14 


FIGURE 5.3(a) EXAMPLES OF CONNECTIONS WHICH MAY BE CONSIDERED 

TO BE FULLY RESTRAINED WITHOUT LATERAL ROTATIONAL RESTRAINT

32 

Beam 

supported 

under 

Beam 

supported 

over 

Continuous under 

supporting beam 

Continuous over 

supporting beam 

column or wall 

FIGURE 5.3(b) EXAMPLES OF CONNECTIONS WHICH MAY BE CONSIDERED 

TO BE PARTIALLY RESTRAINED WITHOUT LATERAL ROTATIONAL RESTRAINT 


33 

Masonry or 

concrete wall 

FIGURE 5.3(c) EXAMPLES OF CONNECTIONS WHICH MAY BE CONSIDERED 

TO BE LATERALLY ROTATIONALLY RESTRAINED 


34 

5.1.6 Design of restraining elements 

Restraint against lateral deflection The lateral restraint at any section 

is to be designed to have a capacity to transfer a transverse force acting 

in either direction at the critical flange equal to 0.025 times the 

maximum force in the critical flange. 

AS 4100 Ref. 

5.4.3 * 

Restraint against twist rotation A torsional restraint at a cross-section 

may be deemed to provide effective restraint against twist rotation if it 

is designed to transfer a transverse force equal to 0.025 times the 

maximum force in the critical flange from any unrestrained flange to 

the lateral restraint. 

Parallel restrained member When a series of parallel members is 

restrained by a line of restraints, each restraining element is to be 

designed to transfer a transverse force equal to the sum of 0.025 times 

the flange force from the connected member and 0.0125 times the sum 

of the flange forces in the connected members beyond, except that no 

more than seven members need be considered. 

Restraint against lateral rotation A restraint at a cross-section which 

is considered to be fully or partially restrained may be deemed to 

provide restraint against lateral rotation out of the plane of bending, 

providing its flexural stiffness in the plane of rotation is comparable 

with the corresponding stiffness of the restrained member. 

For restraint against lateral buckling, the design force needs to be equal to 2.5% of the flange force caused 

by M*. 

The rule for parallel restrained members may be interpreted to mean that each restraining element is to be 

designed for 10% of the flange force in one of the connected members. Provision should be made for 

anchoring the restraining system effectively. 


35 

5.1.7 Angles as simple beams 

Angles subject to bending in a principal plane are to be assessed as in 

Para. 5.1.4.2. Angles subject to bending in a non-principal plane are to 

be assessed using a rational analysis with the calculated principal axis 

bending moment satisfying the requirements for biaxial bending of 

Chapter 8. 

AS 4100 Ref. 

5.7 

For grade 300 angles which are subject to a design moment M* about an axis n-n normal to one leg, and 

which are— 

(a) torsionally restrained at supports, and 

(b) under continuous lateral restraint (see Fig. 5.4(a)), 

the following approximation may be useful (but not always conservative) for preliminary design: 

M* ≤ 0.9 β f y Z min 

where Z min is the minimum elastic section modulus about the relevant axis normal to the leg, and 

β = 1.2 for equal angles 

β = 1.1 for unequal angles with the vertical leg (long or short) down 

β = 1.0 for unequal angles with the vertical leg (long or short) up. 

For angles without lateral restraint which are subject to a design moment M* about an axis n-n normal to 

one leg (see Fig. 5.4(b)), designers are referred to AISC Design Capacity Tables for Structural Steel, 2 nd 

Edition, Volume 1: Open Sections (including Addendum No. 1). It is not possible to propose a simple 

rule of thumb similar to that given above for angles with continuous lateral restraint; the maximum design 

moment will usually reduce with increasing span, and shear/torsion may control the design up to even 

moderate spans. The moment capacity is most reduced for the case of an unequal angle with the long leg 

up. 

W 

W 

n n n n 


(a) With lateral restraints 

(b) Without lateral restraints 

FIGURE 5.4 REPRESENTATION OF ANGLE SITUATIONS

36 

5.2 DESIGN OF WEBS 

5.2.1 Limitations 

The recommendations in this Section are applicable to webs with d/t 

values less than the plastic limit given for webs in flexural 

compression in Table 5.1. The webs are unstiffened with respect to 

their resistance to shear forces and bending but may have load bearing 

stiffeners for concentrated loads and reactions. 

AS 4100 Ref. 

5.10.1 

For webs exceeding these limits, stiffeners should be used or if the web is unstiffened, the shear 

6400 250 

capacity of 5.2.2 should be reduced by a factor αv = 

(rule 5.11.5.1 of AS 4100) 

2 

( d / t ) f 

(As this Handbook does not provide advice concerning stiffeners, dp = d 1 

) 

5.2.2 Shear capacity 

AS 4100 Ref. 

• For sections with webs V * ≤ 0.9 kss (0.6 fy Aw ) 5.11.1 

5.11.2 

• For circular hollow sections V * ≤ 0.9 (0.36 fy Ae) 5.11.3 

5.11.4 

where 

kss = a factor for type of shear stress distribution (see Fig. 5.5) 

Aw = d v t w 

For I sections, d v is the clear depth between flanges. 

For a coped section d v (see Fig. 5.5) should be greater than d 1 /2, and the length of cope should be kept to 

d 1 /2 for single coped and d 1 /4 for double coped sections to avoid the problem of shear and bending 

interaction. For coping lengths longer than these limits, the effects of shear and bending moment 

interaction should be considered (see Clause 5.12 of AS 4100). 

Design shear capacities for universal sections are given in Design aids D3-D4. 

Design shear capacities for welded sections are given in Design aids D5-D6. 

p 

w 

y 


37 

UNCOPED COPED DOUBLE COPED 

dv = d 1 

dv 

dv 

(a) Cope details 

dv 

dv 

dv 

k ss = 1.0 k ss = 0.89 k ss = 0.81 

(b) Shear stress distribution 

FIGURE 5.5 FACTOR FOR SHEAR STRESS DISTRIBUTION 

N.B. 

For RHS, the outside radius of 

section applies here instead of 

the flange thickness. 

(Refer Fig. 5.13.1.3 of AS 4100) 

1:2.5 

bs 

t f 

bs 

1:1 

1:1 

b bf 

b b 


b 1:2.5 

bf 

b b 

FIGURE 5.6 DISPERSION OF FORCES THROUGH FLANGES AND WEBS

38 

5.2.3 Bearing 

Design requirements 

AS 4100 Ref. 

A web subject to a bearing force R * needs to be reinforced with load 

bearing stiffeners if : 

where 

and 

R * > 0.9 times the lesser of R by and R bb 

5.13.2 

R by = the nominal yield capacity in bearing 5.13.3 

= 1.25 b bf t w f y for sections other than square and 

rectangular hollow sections 

b bf = 5t f +b s 5.13.1 

R bb = the nominal buckling capacity in bearing 

buckling 

= axial compressive capacity of a member (with 

 

b = 0.5 and k f = 1.0) of area t w b b and 

slenderness ratio 2.5d 1 /t w where b b is the load 

dispersion length at mid depth of the web 

b b = 5t f + b s + d 1 

for interior force 

= 2.5t f + b s + d 1 

/2 for end force 

5.13.4 

See Fig. 5.6 for illustration of bbf and bb. 

AS 4100 provides a method for the calculation of R by for the case of square and rectangular hollow 

sections. The simple expression for R by given above is only applicable if the web is in direct compression 

such as in an I section. In square and rectangular hollow sections with an external radius, the web is under 

combined bending and compression; the use of the simple expression could be up to 40% unconservative, 

and the procedure in AS 4100 is thus recommended if the bearing load is very high. 

Tabulated values of (Rby/bbf) and (Rbb/bb) are given in Design aids D3-D6 in Part II. 


39 

5.2.4 Load bearing stiffeners 


If load bearing stiffeners are needed, they should be provided in pairs 

(one on each side of the web) at the mid-point of the stiff bearing 

length, such that both: 

(a) 

b es 

≤14 t (for 300 grade) or b ≤12t s 

(for 400 grade) 

es s 

AS 4100 Ref. 

5.10.2 

5.14.1 

5.14.2 

5.14.3 

(b) 

where 

b es 

is the stiffener outstand from the face of the web and t s 

is the 

thickness of this stiffener 

and 

R* ≤ 0.9 times the lesser of R sy 

and R sb 

where 

R sy 

= the nominal yield capacity in bearing (stiffened 

web) 

= R by 

+ A s 

f ys 

R by 

is calculated in 5.2.3 and A s 

is the area of the stiffeners in 

contact with the flange 

R sb 

= nominal buckling capacity of the stiffened web 

= axial compressive capacity of a member 

(with b = 0.5 and k f 

= 1.0) of area taken as the area of the 

stiffener together with a length of web on each side of the 

centre-line equal to 16 t (for 300 grade) or 14 t w 

(for 400 

w 

grade). The effective length of this member shall be equal to the 

clear depth between flanges. 


40 

5.2.4 Load bearing stiffeners (continued) 

Design for torsional end restraints 

AS 4100 Ref. 

When load bearing stiffeners are the sole means of providing torsional 

end restraint at supports, they should be proportioned to have at least 

the following second moment of area I s about the centre-line of the 

web 

5.14.5 

where 

I 

s ≥ 

d 

3 

t 

f 

R 

250F 

F * = total design load on the member between supports 

* 

* 

This rule is a conservative approximation to rule 5.14.5 of AS 4100. 


41 

6 MEMBERS SUBJECT TO AXIAL COMPRESSION 

The procedure for checking a member subject to compression is as follows: 

(a) Estimate the k f value for the section using the BHP Handbook or similar; for fabricated sections use 

Clause 6.2 of AS 4100. 

(b) Estimate the design section capacity, i.e. the short column capacity Ns = 0.9 kf An fy (=Ns which is 

tabulated in Design aids D3-D6). 

(c) Select the member section constant b, to allow for residual stresses and section type, from 

Table 6.2. 

(d) Estimate the member effective length factor ke (from Para. 6.5). 

(e) Estimate the slenderness ratio (ke l/r) for the relevant buckling axis. 

(f) Obtain the member slenderness reduction factor c from Table 6.3. 

(g) The axial load nominal design capacity is cNs. 

Note that all columns in simple construction should be designed for a nominal load eccentricity 

(see Para. 4.3.2) and, therefore, have to be checked for combined axial compression and bending. 

6.1 GENERAL 

AS 4100 Ref. 

For a concentrically loaded member subject to a design axial 

6.1 

compressive force N * , it is recommended that: 

6.2.1 

N * ≤ 0.9 N c ( = 0.9 c N s ) 

i.e. N * ≤ 0.9 c k f A n f y 

where 

N c 

N s 

c 

= the nominal capacity of the member in axial 

compression 

= the nominal capacity of the section in axial 

compression as specified in Para. 6.2 

= a member slenderness reduction factor as specified in 

Para. 6.4 


42 

6.2 NOMINAL SECTION CAPACITY 

The nominal capacity of a section in axial compression is given by 

N s = A e f y 

AS 4100 Ref. 

6.2 

where 

Ae = k f A n = effective area of the cross-section 

k f 

= form factor and is given in BHP Structural Products 

Handbook or similar 

For a section with maximum (b/t) more than the yield limit of Table 6.1, the effective area should be 

calculated from the gross area by summing the effective areas of the individual elements, where effective 

widths are given by be = b((b/t)lim/(b/t)actual). Refer to AS 4100 for further details. 

6.3 NOMINAL MEMBER CAPACITY 

The nominal capacity of a member in axial compression is given by 

N c = cN s 

where 

c 

= a member slenderness reduction factor as specified 

in Para. 6.4 

AS 4100 Ref. 

6.3.3 

6.4 MEMBER SLENDERNESS REDUCTION FACTOR c 

The member slenderness reduction factor c may be determined 

from the slenderness ratio l e /r and the member section constant b 

using Table 6.3. 

AS 4100 Ref. 

6.3 


• The slenderness ratio le/r is the ratio of the effective length to 

the radius of gyration about the relevant axis. The effective 

length le is determined from the actual length l and the effective 

length factor ke: 

where ke is specified in 6.5 

le = ke l 

• The member section constant b is specified in Table 6.2. 

The member section constant α b reflects the section type and the residual stress distribution and 

magnitude.

43 

Table 6.1 Limiting width-thickness ratios for elements with axial compression 

Description of element 

Flanges of universal sections 

and channels 

(b/t)lim 

Yield limit 

250 300 350 400 450 

— 14.5 13.5 — — 

Flanges of welded sections — 13 — 11 — 

RHS — — 34 — 30 

Angles — 14.5 13.5 — — 

Tees — 14.5 13.5 — — 

Webs of universal sections — 41 38 — — 

Webs of welded sections — 32 — 27.5 — 

Circular hollow sections (b = d o ) 82 — 58.5 — — 

Table 6.2 Values of member section constant b 

Section description 

Hot-rolled UB and UC sections with 

• flange thickness up to 40 mm 

• flange thickness over 40 mm 

Hot-rolled channels 

Hot-rolled angles 

RHS and CHS 

• cold-formed non-stress-relieved 

• cold-formed stress-relieved 

• hot-formed 

b 

for kf = 1.0 

0 

1.0 

0.5 

0.5 

-0.5 

-1.0 

-1.0 

b 

for kf < 1.0 

0 

1.0 

1.0 

1.0 

-0.5 

-0.5 

-0.5 


Welded H and I sections 

• from flame-cut plates 

• from rolled plates 

— flange thickness up to 40 mm 

— flange thickness up to 40 mm 

Tees flame-cut from universal sections 0.5 1.0 

Welded box sections 0 0 

Other sections 0.5 1.0 

0 

0.5 

1.0 

1.0 

0.5 

1.0

44 

Table 6.3 Values of member slenderness reduction factor, c , for k f = 1.0 


le/r Compression member section constant ( b ) le/r 

grade 300 -1.00 -0.50 0.00 0.50 1.00 grade 400 

10 1.000 1.0 00 1.000 1.000 1.000 8.5 

20 0.999 0.985 0.972 0.958 0.943 17 

30 0.987 0.961 0.933 0.902 0.868 26 

40 0.963 0.928 0.889 0.844 0.791 34.5 

50 0.928 0.886 0.837 0.779 0.713 43 

60 0.882 0.833 0.775 0.709 0.637 52 

70 0.825 0.768 0.704 0.635 0.566 60.5 

80 0.754 0.692 0.627 0.562 0.501 69 

90 0.672 0.611 0.550 0.494 0.442 78 

100 0.587 0.532 0.480 0.433 0.391 86.5 

110 0.507 0.460 0.418 0.380 0.347 95 

120 0.436 0.399 0.365 0.335 0.308 104 

130 0.376 0.347 0.320 0.296 0.275 112.5 

140 0.327 0.304 0.283 0.263 0.246 121 

150 0.286 0.267 0.251 0.235 0.221 130 

160 0.252 0.237 0.224 0.211 0.200 138.5 

170 0.223 0.211 0.201 0.191 0.181 147 

180 0.199 0.190 0.181 0.173 0.165 155.5 

190 0.179 0.171 0.164 0.157 0.151 164.5 

200 0.161 0.155 0.149 0.143 0.138 173 

210 0.146 0.141 0.136 0.131 0.127 181.5 

220 0.133 0.129 0.125 0.121 0.117 190.5 

230 0.122 0.118 0.115 0.111 0.108 199 

240 0.112 0.109 0.106 0.103 0.100 207.5 

250 0.103 0.101 0.098 0.096 0.093 216.5 

260 0.096 0.093 0.091 0.089 0.087 225 

270 0.089 0.087 0.085 0.083 0.081 233.5 

280 0.082 0.081 0.079 0.077 0.076 242.5 

290 0.077 0.075 0.074 0.072 0.071 251 

300 0.072 0.071 0.069 0.068 0.067 259.5

45 

6.5 MEMBER EFFECTIVE LENGTH FACTOR ke 

6.5.1 General 

The member effective length factor ke depends on the rotational 

restraints and the translational restraints at the ends of the member. It 

may be determined by the simple method in Para. 6.5.2 or by the more 

refined method in Para. 6.5.3. 

AS 4100 Ref. 

4.6.3 

The member effective length in compression varies with the condition to be checked. 

For out-of-plane buckling, the effective length is the distance between lateral restraints. 

If the interaction effect is computed using Appendix B, then the following should be noted: 

For in-plane buckling, the effective length for checking the member as a column (i.e. without bending) is 

the effective length as determined using Para. 6.5.2 and 6.5.3, but the effective length for checking the 

member under combined action is the actual length of the member as given in Appendix B. 

l 

1 

l 

out of plane restraint 

l 

2 

FIGURE 6.1 FREESTANDING COLUMN WITH LATERAL BRACING 


Referring to Figure 6.1 above note that: 

(a) for out-of-plane buckling l e = max (l 1 

, 0.85l 2 

) 

(b) for in-plane buckling 

(i) as axial compression member l e = 2.2l 

(ii) under combined action l e = l

46 

6.5.2 Simple method 

The factor ke may be determined in accordance with Figure 6.2 for 

braced members in frames, or for sway members in rectangular frames 

with regular loading and negligible axial force in the beams. The 

effective length le of a member in a triangulated structure may be taken 

as not less than its length l from centre to centre of intersections with 

other members. 

AS 4100 Ref. 

4.6.3 

6.5.3 is generally applicable to members in frames where the idealised conditions of end restraints given 

in 6.5.2 are not realisable. 

Braced member—one for which the transverse displacement of one end of the member relative to the 

other is effectively prevented. This situation applies in triangulated frames or trusses or to frames where 

in-plane stiffness is provided by diagonal bracing, or by shear walls, or by floor slabs or roof decks 

secured horizontally to walls or to bracing systems parallel to the plane of buckling of the member. 

Sway member—one for which the transverse displacement of one end of the member relative to the other 

is not effectively prevented. Such members occur in structures which depend on flexural action to limit 

the sway. 

BRACED MEMBER 

SWAY MEMBER 

BUCKLED 

SHAPE 

Effective length 

factor (k e ) 

0.70 0.85 1.00 1.20 2.20 2.20 

Symbols for end 

restraint conditions 

= Rotation fixed, Translation fixed 

= Rotation free, Translation fixed 

= Rotation fixed, Translation free 

= Rotation free, Translation free 


FIGURE 6.2 EFFECTIVE LENGTH FACTORS FOR MEMBERS FOR 

IDEALIZED CONDITIONS OF END RESTRAINT

47 

6.5.3 Refined method 

For a compression member that forms part of a rigidly jointed structure, 

the member effective length factor ke may be obtained from 

Figure 6.3(a) for a braced member and from Figure 6.3(b) for a sway 

member. In Figure 6.3(a), the translational restraint is assumed to be 

infinite and in Figure 6.3(b) it is assumed to be zero. 1 

and 2 

are the 

ratios of the compression member stiffnesses to the end restraint 

stiffnesses and are determined, if there is negligible axial force in the 

beams, by: 

∑ ( I / l) 

c 

γ = 

∑ β I / l 

e 

( ) b 

except that for a compression member whose base is: 

(a) rigidly connected to a footing, the value is not to be taken as less 

than 0.6. 

(b) not rigidly connected to a footing, the value is not to be taken as 

less than 10. 

AS 4100 Ref. 

4.6.3.3 

The quantity ∑ ( I / l) 

c is calculated from the sum of the stiffnesses in the 

plane of bending of all the compression members rigidly connected at 

the end of the member under consideration, including the member itself. 

The quantity ∑ β e ( I / l) 

b is calculated from the sum of the stiffnesses in 

the plane of the bending for all the beams rigidly connected to the end of 

the member under consideration. The contributions of any beams pinconnected 

to the member are neglected. 

The modifying factor β e , which accounts for the condition at the far 

ends of the beams, is determined from Table 6.4. 

Table 6.4 Modifying factor e for joint stiffness 


Fixity condition at far end of 

beam 

Beam restraining 

a braced member 

Beam restraining 

a sway member 

Pinned 1.5 0.5 

Rigidly connected to a column 1.0 1.0 

Fixed 2.0 0.67

4 

3 

2.5 

2.0 

48 

8 

50 

10 

6 

4 

3 


8 

8 

50 

10 

6 

0.95 

50 

10 

6 

4 

3 

0.90 

4 

3 

1.8 

1.6 

1.5 

1.4 

k e 

1.3 

1.25 

1.20 

1.15 

2 

1.5 

1.2 

1.0 

0.5 

STIFFNESS RATIO AT END 1, γ1 

0.85 

0.80 

k e 

0.75 

0.70 

0.65 

2 

1.5 

1.2 

1.0 

0.5 

STIFFNESS RATIO AT END 1, γ1 

1.10 

0.60 

1.05 

0.55 

0 

0 0.5 1.0 1.2 1.5 2 

STIFFNESS RATIO AT END 2, γ 2 

8 

0 

0 0.5 1.0 1.2 1.5 2 3 4 6 10 50 

STIFFNESS RATIO AT END 2, γ 2 

(a) For braced members (b) For sway members 

FIGURE 6.3 EFFECTIVE LENGTH FACTORS

49 

6.6 ECCENTRICALLY LOADED DOUBLE BOLTED OR WELDED 

SINGLE ANGLES 

AS 4100 Ref. 

AS 4100 requires that eccentrically loaded, double bolted or welded, 8.4.6 

single angles be treated as a combined action problem. 

Clause 8.4.6 of AS 4100 is applicable only to single angle web 

compression members in trusses. 

For the general problem of angles as compression members loaded through the leg, the approach of 

Clause 8.4.6 of AS 4100, if used, is conservative and can be approximated by the following simplified 

method: 

Single angle web compression members in trusses, which are connected with at least two bolts or welded 

at their ends and loaded through one leg (see Fig. 6.4), may be designed as axially loaded members in 

accordance with Para. 6.1, but with slenderness ratios modified to account for end eccentricities and 

fixities as follows: 

Angles on the same side (l/r)e = 0.45(l/ry)+130 

Angles on opposite sides (l/r)e = 0.30(l/ry)+250 

where l is the member length and ry is the radius of gyration about the minor principal axis. 

For the design of lattice tower members, refer to AS 3995—1994. 

Web 

tension 

member 

Web 

compression 

member 

Web 

tension 

member 

Web 

compression 

member 

Chord 

Chord 

(a) Angles on same side 

(b) Angles on opposite sides 


FIGURE 6.4 SINGLE ANGLES LOADED THROUGH ONE LEG

50 

7 MEMBERS SUBJECT TO AXIAL TENSION 

AS 4100 Ref. 

For a member subject to an axial tension force N * , it is recommended 7.1 

that : 

7.2 

N * ≤0.9 N 

7.3 

t 

where 

N t 

where 

An 

A g 

kt 

= nominal capacity of the member in tension 

= the lesser of A g f y (section capacity) and 0.85kt An fu 

= net area of the cross-section 

= gross area of the cross-section 

= a factor for eccentricity of loading 

= 1.00 where there is uniform force distribution 

= 0.90 for tee sections connected by flange 

= 0.85 for: 

• channel sections connected by web 

• equal angles connected by leg 

• unequal angles connected by long leg 

• I sections or channels connected by both flanges only 

= 0.75 for unequal angles connected by short leg 

For any eccentric connections other than the above, it is suggested that k t = 0.75. 

For threaded rods k t = 1.0 and A n = tensile stress area of the equivalent threaded fastener (refer to 

Para. 9.2.5 for tensile stress area). 

For holding down bolts, f y and f u of the material used for the bolt may not be the same as that for bolts to 

AS/NZS 1111 and therefore can be designed to this Chapter instead of Chapter 9. 


51 

8 MEMBERS SUBJECT TO COMBINED ACTION 

The interaction equation for a section subject to an axial load, N * , a 

major axis bending moment, M , and a minor axis moment M : 

where 

N 

M bx 

M by 

N 

0.9N 

* 

x 

* * 

* 

M x 

+ 

0.9M 

bx 

M y 

+ 

0.9M 

by 

≤1.0 

= N t or N c = the nominal axial tension or compression 

capacity, respectively, of the member (for a 

compression member it is the lesser of the capacities 

for either principal axis). 

= nominal capacity of the member in bending about the 

x-axis 

= nominal capacity of the member in bending about the 

y-axis 

* 

y 

AS 4100 Ref. 

8 

This is a simplified procedure which avoids the need for checking section and member capacity 

separately. Considerably less conservative results can be obtained by using the more complex checking 

procedure of AS 4100 which is explained in Appendix B. 


52 

9 CONNECTIONS 

9.1 MINIMUM DESIGN ACTIONS ON CONNECTIONS 

AS 4100 Ref. 

Connections are to be designed to transmit the greater of: 9.1.4 

(a) the design action in the member 

(b) the minimum design actions specified below: 

Type of connection 

Minimum design action 

In rigid construction 

In simple construction 

Axially loaded member 

Full contact bearing splices in 

compression 

Other splices 

Threaded rods 

0.5 (member design moment 

capacity) 

40 kN shear force 

0.3 (member design capacity) 



member design capacity 

For rigid construction, the connection is assumed to have sufficient stiffness to hold the original angles 

between the members unchanged. 

For simple construction, the connections at the ends of members are assumed not to develop bending 

moments. 

In addition, for plastic design of beams, the shear connections at the ends of a beam require adequate 

rotational capacity so that a plastic hinge can form elsewhere in the beam. This requirement must be 

achieved without reducing the connection shear capacity. 


53 

9.2 DESIGN OF BOLTS 

9.2.1 Bolts and bolting categories 

AS 4100 Ref. 

Bolting 

category 

Bolt standard 

Bolt grade 

Method of 

tensioning 

fuf 

(MPa) 

9.3.1 

4.6/S AS/NZS 1111 4.6 Snug tight 400 

8.8/S AS/NZS 1252 8.8 Snug tight 830 

8.8/TB AS/NZS 1252 8.8 Full tensioning 830 

8.8/TF AS/NZS 1252 8.8 Full tensioning 830 

Refer to Chapter 7 for the design of holding-down bolts. 

9.2.2 Detailing requirements 

(a) Pitch and edge distance 

AS 4100 Ref. 

• Minimum pitch 2.5df 9.6 

• Maximum pitch lesser of (15tp, 200 mm) 

• Minimum edge 

distance 

Sheared or hand flame-cut edge 

Rolled plate, flat bar or section: 

machine flame-cut, sawn or 

planed edge 

Rolled edge of rolled flat bar or 

section 

1.75df 

1.50df 

1.25df 

(b) Hole type 


AS 4100 Ref. 

• Standard (kh = 1.0) dh < df + 2 mm df ≤ 24 mm 14.3.5.2 

9.3.3.1 

dh < df + 3 mm df > 24 mm 

• Oversize (kh = 0.85) dh ≤ max (1.25d f, df + 8 mm) * 

• Short slot (kh = 0.85) lh ≤ max (1.33d f, df + 10 mm) * 

• Long slot (kh = 0.70) lh < 2.5df 

* These are the requirements for oversize and short slotted holes as presented in AS 4100, 14.3.5.2 (a) 

(i) and (ii). However, in the now withdrawn High-strength Structural Bolting Code (AS 1511), these 

requirements were based on the minimum, not the maximum, of the two values.

54 

9.2.3 Strength requirements 

Condition 


AS 4100 Ref. 

Bolts in tension 

Bolts in shear 

f 

f 

N 

* ≤ 0.8N 

= 0. 8A 

f 

9.3.2.2 

tf 

tf 

V 

* ≤ 0. 8V 

= ( 0.8)(0.62) k r fuf 

( nn 

Ac 

+ nx 

Ao 

) 9.3.2.1 

s 

uf 

Bolts in bearing V 

* 

b 

0.9Vb 9.3.2.4 

Bolts in combined 

tension and shear 

⎛ 

⎜ V 

f 

⎜ 0.8V 

⎝ 

= lesser of 0.9ae t p f up 

and ( 09 . )( 32 . ) df t p f up 

* ⎞ 

2 

⎞ 2 

f 

⎟ 

⎟ 

⎠ 

⎛ * 

⎜ N 

tf 

+ 

⎟ 

⎜ 0.8N 

⎟ 

tf 

⎝ ⎠ 

For common bolt sizes, designers may use the design aids given in D1. 

≤1.0 

9.3.2.3 

k r = length factor for lap connection 

= 1.0 for l j < 300 mm 

= 1.075 – l j /4000 for 300 mm ≤ l j ≤ 1300 mm 

= 0.75 for l j > 1300 mm 

n n = No. of shear planes with threads included 

n x = No. of shear planes with threads excluded 

a e = edge distance which is the distance from the nearer edge of a hole and the physical edge of a 

plate or rolled section, plus half the fastener diameter d f 

t p = ply thickness 

f up = tensile strength of ply material 

f uf = minimum tensile strength of the bolt 

A c = bolt minor area (see Para. 9.2.5) 

A o = nominal shank area (see Para. 9.2.5) 

A s = tensile stress area (see Para. 9.2.5) 

d f = diameter of the bolt 

d h = diameter of the hole 

l h = hole length 


55 

9.2.4 Serviceability requirements (bolts in friction grip only) 

AS 4100 Ref. 

Condition Design requirements 9.3.3 

Shear 

V 

* 

sf ≤ 0. 7V sf = (0.7) µ kh n ei N ti 

⎛ * ⎞ ⎛ * ⎞ 

⎜ Vsf 

⎟ ⎜ N 

tf ⎟ 

Combined shear and tension + ≤1. 

0 

⎜ 0.7V 

⎟ 

⎜ 0.7 

⎟ 

sf Nti 

⎝ ⎠ ⎝ ⎠ 

µ = slip factor (0.35 for ‘as rolled’ surfaces) 

k h = hole factor (refer to Para. 9.2.2 (b)) 

d h = hole diameter 

d f = bolt diameter 

l h = hole length of slotted hole 

n ei = number of effective interfaces 

N ti = minimum bolt tension at installation (see Para. 9.2.5) 

If the surface coating is such that the slip factor µ would normally be more than 0.35 and if the load is 

shared by more than two bolts in a line, designers are advised to exercise caution by reducing the slip 

factor by 25%. (This recommendation goes beyond the requirements of AS 4100.) 

9.2.5 Bolt properties for design 

AS 4100 Ref. 

Size M12 M16 M20 M24 M30 M36 

Tensile stress area 

(mm 2 ) 

A s 84 157 245 353 561 817 9.3.2.2 

Shear area 

(thread included) 

(mm 2 ) 

A c 

76.2 

(80) 

144 

(150) 

225 

(235) 

324 

(338) 

519 

(539) 

759 

(787) 9.3.2.1 

Shear area 

(thread excluded) 

(mm 2 ) 

A o 113 201 314 452 707 1017 


Min. tension at 

installation 

(8.8/TF only) 

(kN) 

N ti — 95 145 210 335 490 15.2.5 

The figures in brackets in the table above are those given in AS 1275—1985, which are approximately 

5% larger than those in AS 1275—1972. The more conservative values have been adopted in this 

Handbook.

56 

9.3 DESIGN OF WELDS 

9.3.1 Butt welds 

Complete penetration butt welds: no analysis is required for SP 

welds. The design capacity is equal to the design capacity of the 

weaker part for SP welds and 2/3 of the design capacity of the weaker 

part for GP welds. 

AS 4100 Ref. 

9.7.2 

Incomplete penetration butt welds: the design capacity is calculated 

as for fillet welds using the following design throat thickness tt for 

angle of preparation less than or equal to 60° (see Fig. 9.3): 

Single-V butt 

Double-V butt 

tt = (d – 3) mm 

tt = (d 3 + d 4 – 6) mm 

except for submerged arc welds where the design throat thickness can 

be taken to the full depth of penetration. 

Refer to AS/NZS 1554.1 for definitions of SP, GP and other requirements such as prequalification. 

9.3.2 Fillet welds 

AS 4100 Ref. 

The design capacity of a fillet weld per unit length is 9.7.3.10 

0.36 fuw tt kr for GP welds 

0.48 fuw tt kr for SP welds 


where 

fuw = nominal tensile strength of the weld metal 

= 410 MPa for E41xx/W40x electrodes 

= 480 MPa for E48xx/W50x electrodes 

tt = design throat thickness (see Fig. 9.3) 

kr = a reduction factor for lap connections 

= 1.0 for lw < 1.7 m 

= 1.1 – 0.06l w for 1.7 m < lw < 8.0 m 

= 0.62 for lw > 8.0 m 

lw = weld length 

Design capacities of fillet welds of common sizes are tabulated in Design aid D2.

57 

Reinforcement 

Reinforcement 

Leg 

s 

Q 

θ 

R 

DTT 

90° 

P 

Leg 

s 2 

Q 

θ 

R 

DTT 

90° 

P 

s 

s 1 

Leg 

Leg 

(a) Equal leg fillet weld 

(b) Unequal leg fillet weld 

Design throat thickness for deep penetration 

welds made by fully automatic processes 

DTT 

D 2 D 1 

= D 1 + 0.85D 2 

Leg 

(d) Deep penetration weld 

θ < 60° 

t t 

d 

Leg 

Apparent 

size 

s 

Q 

θ 

R 

90° P 

s 

Gap 

(c) Fillet weld with gap 


t t 

3mm 

(e) Incomplete penetration single V butt weld 

t t 

3mm 3mm 

d 

d 

(f) Incomplete penetration double V butt weld 

FIGURE 9.3 NOTATION FOR WELDS

58 

9.4 SIMPLE SHEAR CONNECTIONS 

AS 4100 Ref. 

The shear capacity and the detailing requirements of a range of simple 

connections are given in Tables 9.4.1 to 9.4.6. For greater detail, 

reference should be made to the Australian Institute of Steel 

Construction publication Standardized Structural Connections—4th 

edition, due 2000. 

Tables 9.4.1 to 9.4.6 are the original ones prepared for the 1993 edition and are based on a plate and 

section grade of 250. Thus some connection capacity values, those based on plate failure rather than bolt 

or weld failure, will be conservative if plate or sections of higher grade are used. 

Table 9.4.1 Single Angle Cleat Connection Capacity 

Single angle cleat connections (kN) 

Member 9 8 7 6 5 4 3 2 

Bolts Bolts Bolts Bolts Bolts Bolts Bolts Bolts 

760UB 531 472 413 354 

690UB 472 413 354 284 

610UB 413 354 284 207 

530UB 354 284 207 136 

460UB 284 207 136 

410UB 207 136 73 

360UB 136 73 

310UB 136 73 

250UB 73* 

* Double web cope not recommended 


ANGLES: USE 100 × 100 × 6 ANGLE, LENGTH = 70 × No. ROWS BOLTS. 

BOLTS: USE M20 8.8\S

59 

Table 9.4.2 Double Angle Cleat Connection Capacity 

Double angle cleat connections (kN) 

Member 9 8 7 6 5 4 3 2 


760UB244-197 1061 943 826 708 

760UB173 1061* 943 826 708 

760UB147 1061* 905 826 708 

690UB140 943* 772 708 568 

690UB125 943* 750 708 554 

610UB125 808* 671 563 411 

610UB113 755* 625 530 386 

610UB101 710* 585 502 366 

530UB92 593* 481 352 230 

530UB82 551* 445 330 216 

460UB82 469* 342 224 

460UB78 430* 314 205 

460UB67 401* 293 192 

410UB60 269* 176 96 

410UB54 262* 172 93 

360UB57 175 97 

360UB51 157 89 

360UB45 144 82 

310UB46 155* 82 

310UB40 138* 75 

250UB37 78** 

250UB31 75** 


** Double or single web cope not recommended 


ANGLES: USE 100 × 100 × 6 ANGLE, LENGTH = 70 × No. ROWS BOLTS 

BOLTS: USE M20 8.8\S

60 

Table 9.4.3 Flexible End Plate Connection Capacity 

Flexible end plate connections (kN) 

Member 9 8 7 6 5 4 3 2 


760UB244-197 1122 1095 958 821 

760UB173 1016 1016 946 811 

760UB147 1066* 905 853 731 

690UB140 918* 772 703 586 

690UB125 894* 750 690 575 

610UB125 808* 671 585 486 

610UB113 755* 625 550 440 

610UB101 710* 625* 521 417 

530UB92 583* 481 401 301 

530UB82 551* 445 375 282 

460UB82 485* 383 292 

460UB78 442* 348 268 

460UB67 409* 321 250 

410UB60 307 230 153 

410UB54 298* 224 149 

360UB57 234* 156 

360UB51 215* 143 

360UB45 202* 135 

310UB46 198* 117 

310UB40 179* 120* 

250UB37 126** 

250UB31 120** 


** Double or single web cope not recommended 


END PLATE: 

BOLTS: 

ALL WELDS: 

WIDTH = 150 mm, THICKNESS = 8 mm, LENGTH = 70 × No. ROWS BOLTS 

USE M20, 8.8\S 

USE 6E48 FILLET WELDS — FULL LENGTH OF PLATE

61 

Member 

Table 9.4.4 Bearing Pad Connection Capacity 

Bearing pad connections (kN) 

End plate Bearing pad CAP. 

Member 

Bearing pad connections (kN) 

End plate Bearing pad CAP. 

760UB244 140×800×25 140×650×25 1144 310UB46 90×320×20 90×200×20 290 

760UB220 1144 310UB40 260 

760UB197 1144 250UB37 90×270×20 90×150×20 230 

760UB173 1144 250UB31 215 

760UB147 1144 200UB30 90×220×20 183 

690UB140 140×700×25 1082 200UB25 167 

690UB125 1082 310UC283 90×360×25 90×300×25 579 

610UB125 140×630×25 140×600×25 962 310UC240 579 

610UB113 955 310UC198 579 

610UB101 140×550×25 896 310UC158 579 

530UB92 90×550×25 90×500×25 763 310UC137 579 

530UB82 90×450×25 708 310UC118 525 

460UB82 90×480×25 90×400×25 640 310UC97 428 

460UB74 90×470×20 90×400×20 583 250UC89 90×280×20 90×250×20 352 

460UB67 90×350×20 540 250UC73 90×200×20 308 

410UB60 90×420×20 90×300×20 445 200UC60 90×230×20 273 

410UB54 429 200UC52 232 

360UB57 90×380×20 400 200UC46 90×150×20 209 

360UB51 90×250×20 364 150UC37 90×180×20 185 

360UB45 339 150UC30 145 

150UC23 131 


PLATES: USE DIMENSIONS AS GIVEN IN TABLE 

BOLTS: USE M20, 8.8\S 

WELDS: USE 6 mm E48 FILLET WELDS — FULL LENGTH OF PLATES , OR 

USE 8 mm E48 FILLET WELDS — FULL LENGTH OF PLATES (310UC ONLY)

62 

Member 

Table 9.4.5 Angle Seat Connection Capacity 

Angle seat connections (kN) 

Bolted 

seat 

6E48 

Welded 

seat 

8E48 

Welded 

seat 

Member 

Angle seat connections (kN) 

Bolted 

seat 

6E48 

Welded 

seat 

8E48 

Welded 

seat 

760UB244 - - 386 310UB46 151 151 151 

760UB220 - 287 386 310UB40 135 135 135 

760UB197 357 287 386 250UB37 357 287 386 

760UB173 357 287 386 250UB31 357 287 386 

760UB147 342 287 342 200UB30 357 287 386 

690UB140 331 287 331 200UB25 357 287 386 

690UB125 308 287 308 310UC283 357 287 385 

610UB125 318 287 318 310UC240 329 287 329 

610UB113 287 287 287 310UC198 260 260 260 

610UB101 259 287 259 310UC158 NR NR NR 

530UB92 225 252 255 310UC137 NR NR NR 

530UB82 228 228 228 310UC118 NR NR NR 

460UB82 237 237 237 310UC97 NR NR NR 

460UB74 213 213 213 250UC89 NR NR NR 

460UB67 192 192 192 250UC73 NR NR NR 

410UB60 180 180 180 200UC60 NR NR NR 

410UB54 168 168 168 200UC52 NR NR NR 

360UB57 183 183 183 200UC46 NR NR NR 

360UB51 165 165 165 150UC37 NR NR NR 

360UB45 151 151 151 150UC30 NR NR NR 

150UC23 NR NR NR 


ANGLE SEAT: USE 150 × 90 × 12 ANGLE, LENGTH = 180 mm, SHORT LEG IS USED AS SEAT 

(MAY BE BOLTED OR WELDED AS GIVEN) 

RESTRAINING 

CLEAT: USE 100 × 75 × 6 ANGLE, LENGTH = 140 mm 

BOLTS: USE M20, 8.8\S 

WELDS: USE 6 mm E48 FILLET WELDS—FULL LENGTH OF SEAT LEG (2 × 150 mm), OR 

USE 8 mm E48 FILLET WELDS—FULL LENGTH OF SEAT LEG (2 × 150 mm) 

(AS GIVEN IN TABLE)

63 

Table 9.4.6 Web Side Plate Connection Capacity 

Web side plate connections (kN) 

Member 9 8 7 6 5 4 3 2 


760UB 726* 632 538 444 

690UB 632* 538 444 351 

610UB 538* 444 351 260 

530UB 444* 351 260 173 

460UB 351* 260 173 

410UB 260* 173 96 

360UB 173 96 

310UB 173* 85 

250UB 85* 


SIDE PLATE: 

BOLTS: 

WELDS: 

WIDTH = 90 mm, THICKNESS = 10 mm, LENGTH = 70 × No. ROWS BOLTS 

USE M20, 8.8\S 

USE 6E48 FILLET WELDS — FULL LENGTH OF PLATE 


64 

10 BRITTLE FRACTURE 

Brittle fracture is unlikely if all of the following conditions apply: 

AS 4100 Ref. 

10.4 

• Thickness does not exceed 70 mm 

• Not exposed to sub zero temperature 

• Fabrication does not result in a bending radius of less than 50 times 

the plate thickness 

This Handbook highlights the conditions under which brittle fracture is not a problem; otherwise refer to 

AS 4100 for detailed consideration. 


65 

11 FATIGUE 

11.1 LIMITATIONS 

The advice in this Section is applicable to conditions where all cyclic 

loadings can be assumed to be equal to the most severe and where 

metal thickness does not exceed 25 mm. 

AS 4100 Ref. 

11 

This Handbook highlights the conditions under which fatigue is not a problem; otherwise refer to 

AS 4100 for detailed consideration. 

11.2 METHOD OF ASSESSMENT 

(a) Number of stress cycles: estimate the number of stress cycles n i for 

the expected life of the detail. If n i < 10 4 (i.e. one application every 

day for 25 years), no further assessment is required. 

(b) Stress range: estimate the stress range f * , i.e. the algebraic 

difference between two extremes of stress. The stresses are 

calculated taking into account all cyclic design actions but 

excluding stress concentrations due to the geometry of the detail. 

The loading is to be the actual cyclic service loading including 

dynamic effects. 

No further assessment is required if: 

(i) f * < 26 MPa or 

3 

⎛ 

6 27 

⎞ 

(ii) n i < 5 10 ⎜ ⎟ ⎛ 

11 

× 

⎜ * ⎟ 

⎝ f ( ) ⎟ ⎞ 

⎜ 

10 

= 

3 

⎠ ⎝ f * 

⎠ 

(c) Detail category: select the appropriate detail category in accordance 

with Table 11, to obtain the constant stress range fatigue limit f 3 . 

(i) 

(ii) 

if f * < f3 no further assessment is required. 

if f * > f3 the number of cycles the detail can survive is 

n i max = 5 × 10 

6 

⎛ ⎞ 

⎜ 

f3 

⎟ 

⎜ * ⎟ 

⎝ f ⎠ 

3 

AS 4100 Ref. 

11.1.6 

11.4 

11.5 

11.7 


If the structural system is such that failures of the detail lead to the collapse of the structure, AS 4100 

requires that the expected life should be increased by a factor of at least 3.0. To avoid this penalty it is 

necessary to modify the structural system to one that is fail-safe (i.e. with alternative load paths).

66 

Table 11 Detail Category 

Type of detail 

• Bolts and threaded rods in tension 

• Joints with partial penetration butt welds or fillet welds (stress 

range on the weld throat) 

• Cover plates in beams and plate girders 

f3 (MPa) 

27 

• Beams subjected to bending with stiffeners fillet-welded to 

flanges and webs 

• Tapered built-up members connected by full penetration buttwelds 

perpendicular to the direction of applied stress 

• Stud-welded base metal 

• Base metal having fillet welded attachments 

52 

• Prismatic members connected by full penetration butt-welds 

perpendicular to the direction of applied stress 

• Bolt in shear 8.8/TB 

• Any continuous longitudinal butt or fillet weld other than those 

with an f 3 value of 92 MPa 

66 

• Manual flame-cut base metal, automatic flame-cut base metal with 

drag line 

• Built-up members connected by continuous full penetration buttwelds 

or continuous fillet welds parallel to the direction of applied 

stress (no unrepaired stop-start positions and welded from both 

sides) 

92 

• Automatic flame-cut or shear edge base metal 

• Material for bolted connection using 8.8/TF procedure 

103 

• Rolled and extruded products 118 


This Table is based on AS 4100 but has been simplified greatly to be used for preliminary fatigue 

assessment. For detailed fatigue assessment refer to AS 4100. 

For bolts subject to fluctuating stresses in tension it is common practice to fully tension the bolt to 

alleviate fatigue problems.

67 

APPENDIX A 

ALTERNATIVE METHOD FOR MOMENT AMPLIFICATION 

A1 

Moment amplification for a braced member 

For a braced member with a design axial compressive force N * and a 

calculated design bending moment M m * as determined by the first order 

analysis, the design bending moment M * is calculated as follows: 

AS 4100 Ref. 

4.4.2.2 

M * = bM * m 

where b is a moment amplification factor for a braced member 

calculated as follows: 

cm 

b = ≥1 

⎛ N * ⎞ 

1− 

⎜ 

⎟ 

⎝ Nomb 

⎠ 

and Nomb is the elastic buckling load for the braced member buckling 

about the same axis as that about which the design bending moment 

M * is applied. 

For a braced member subject to end bending moments only, the factor 

cm is calculated as follows: 

cm = 0.6 – 0.4m ≤ 1.0 

where m is the ratio of the smaller to the larger bending moment at 

the ends of the member, taken as positive when the member is bent in 

reverse curvature. 

For a braced member with a transverse load applied to it, m is taken 

as –1.0 or approximated by the value obtained by matching the 

distribution of bending moment with one shown in Fig. A1. 


N omb = π 2 EI/l 2 e where l e and EI are the effective length and rigidity of the member about the same axis as 

the applied bending moment M*. See Chapter 6, Fig. 6.1 and Fig. 6.2 for braced members. 

For most practical designs the factor N * /Nomb is usually small so that the amplification factor should also 

be small. A limiting value of δb not greater than 1.4 has been set before it is necessary to proceed to a full 

second order analysis. 

Values of l e /r for δb = 1.0 and δb = 1.1 are plotted in Fig. A2 as a function of βm and the applied axial 

load N * /0.9Ns.


Moment distribution β m Moment distribution 

β m Moment distribution β m Moment distribution β m 

M* 

-1.0 

M* 

-1.0 

M* 

M*/2 

-0.4 

M* 

M*/2 

-0.5 

M* 

M* 

+0.2 

M* 

M* 

+0.5 

M* 

M* 

+0.1 

M* 

M* 

-0.1 

M* 

+0.6 

M*/2 

M* 

+1.0 

M*/2 

M* 

+0.7 

M*/2 

M* 

+0.3 

M* 

M*/2 

-0.5 

M* 

M*/2 

+0.4 

M*/2 

M* 

M*/2 

-0.5 

M*/2 

M* 

M*/2 

+0.4 

68 

M* 

M* 

+0.2 

M* 

M* 

0.0 

M*/2 

M* 

M* 

M*/2 

+0.2 

M* 

M* 

-0.1 

M* 

M*/2 

M* 

+0.2 

M* 

M*/2 

M* 

+0.5 

M* 

βM* 

β 

M* 

M* 

+1.0 

FIGURE A1 EXTRACTS FROM AS 4100 FIGURE 4.4.2.2 FOR VALUES OF βm FOR 

VARIOUS DISTRIBUTIONS OF BENDING MOMENT

69 

180 

160 

δ b = 1.1 

δ b = 1.0 


( l e /r) 

140 

120 

100 

80 

p = 0.25 

p = 0.5 

p = 1.0 

60 

40 

N* 

p = 

φN s 

20 

0 

–1.0 0 +1.0 

FIGURE A2 LIMITING VALUES OF 

l e / r FOR MOMENT AMPLIFICATION

70 

A2 

Moment amplification for a sway member 

For a sway member with a design axial compressive force N * and a 

calculated design bending moment M m * as determined by the first order 

analysis, the design bending moment M * is calculated as follows: 

AS 4100 Ref. 

4.4.2.3 

M * = mM * m 

The moment amplification factor m is taken as the greater of— 

b = 

the moment amplification factor for a braced member 

determined in accordance with A1, or 

s = the moment amplification factor for a sway member 

For all sway columns in a storey of a rectangular frame, s is 

calculated from: 

1 

s = 

⎛ ⎞ 

⎜ Σ 

− ∆ * 

s N 

1 

⎟ 

⎜ h ⎟ 

⎝ s ΣV 

* 

⎠ 

where ∆s is the translational displacement of the top relative to the 

bottom in the storey of height hs, caused by the design horizontal 

storey shears V * at the column ends, N * is the design axial force in a 

column of the storey, and the summations include all the columns of 

the storey. 

ΣN 

* 

The term 

ΣV 

* 

above the storey. 

can also be considered as the ratio of the total vertical loads to the total horizontal loads 

The limiting value for m is set at 1.4 for rectangular frames but for most practical designs the 

amplification factor should be considerably less. If m is greater than 1.4 then it is necessary to perform a 

second order analysis. 


71 

A3 

Moment amplification for pitched-roof portal frames 

λ 

The moment amplification factor for a steel pitched-roof portal 

frame is obtained from the frame elastic buckling load factor λ c 

using: 

1 

δ = 

1 − (1/ 

λ c 

) 

AS 4100 Ref. 

4.4.2.3 

where 

cis the ratio of the elastic buckling load set of the frame to 

the design load set (with load factors) for the frame. 

• For sway buckling mode 

3EIr 

λc 

= 

s[ 

P h + 0.3P s] 

c 

r 

for pinned based frames 

5E(10 

+ R) 

λc 

= 

2 

2 

(5Pr 

s / I r ) + (2RPc 

h / I c ) 

for fixed based frames 

where 

I c , I r = the second moments of area of the column and 

rafter, respectively 

P c , P r = the averages of the computed first-order 

compression forces in the columns and rafters, 

respectively 

s = the length of the rafter 

h = the height to the eaves 

R = (I c /h) / (I r /s) 


72 

A3 

Moment amplification for pitched-roof portal frames (continued) 

• For symmetrical buckling mode 

2 

π EI r 

λ c 

= 

2 

(2k 

s) 

P 

in which the effective length factor k e is obtained from the braced 

member effective length chart of Figure 6.3 by using: 

e 

r 

AS 4100 Ref. 

4.4.2.3 

γ 

1 

= γ 2 

= 

I r / 2s 

1.5I 

/ h 

c 

for pinned based frames 

γ 

1 

= γ 2 

= 

I r / 2s 

2I 

/ h 

c 

for fixed based frames 

The above buckling formulae have been obtained from J.M. Davies In-plane Stability of Portal Frames, 

The Structural Engineer Vol. 68, No. 8, April 1990. For multi-bay formulae, refer to J.M. Davies The 

Stability of Multi-bay Portal Frames, The Structural Engineer Vol. 69, No. 12, June 1991. 


73 

APPENDIX B 

ALTERNATIVE METHOD FOR MEMBERS 

SUBJECT TO COMBINED ACTIONS 

The checking of a member subject to combined axial and bending actions may be carried out as follows: 

(a) Establish design section capacities under separate axial and bending actions using Chapters 5, 6 

and 7 as appropriate. 

(b) Use interaction equations in B2 to check design section capacity under combined actions. 

(c) Establish the effective lengths for in-plane and out-of-plane actions for the member. 

(d) If the member is subject to compression, first check it as a compression member in accordance 

with Chapter 6. 

(e) Establish the design member capacity under separate axial and bending action using Chapters 5, 6 

and 7 as appropriate. For in-plane action use the actual member length for the effective length in 

compression. 

(f) 

Use interaction equations in Para. B3 to check the design member capacity under combined actions. 

Note that all members under combined axial compression and bending are to be checked separately 

for axial compression without bending as given in Chapter 6, and then for the combined actions as 

given in Chapter 8 because different effective lengths have to be used in each case. 

Section capacity requirements often control the design of highly restrained members while member 

capacity requirements often control the design of members without full lateral restraint. 

B1 

GENERAL 

For a member subject to combined axial and bending actions, it is 

recommended that the requirements for section capacity under 

combined action be checked in accordance with Para. B2 and member 

capacity under combined action be checked in accordance with 

Para. B3. 

AS 4100 Ref. 

8.1 

Eccentrically loaded angles may be designed using Para. 6.6. 


Note that the applied bending moments Mx * and My * used in the interaction equations of this 

Section are amplified bending moments. They are obtained by modifying the first order design 

bending moments with the appropriate moment amplification factors determined in accordance 

with Para. 4.4.2 or Appendix A.

74 

B2 

SECTION CAPACITY UNDER COMBINED ACTIONS 

B2.1 Section under uniaxial bending and axial force (tension or compression) 

The interaction equation for a section subject to a bending moment 

M * about a principal axis and an axial force N * is: 

⎛ * * ⎞ 

⎜ N M 

+ ⎟ ≤1.0 

⎜ 0.9N 

0.9 ⎟ 

s kM 

⎝ 

s 

⎠ 

where 

k = 1.18 for doubly symmetric compact I-sections and 

rectangular and square hollow sections with k f = 1.0 

= 1.00 for other sections 

M s = nominal capacity of the section in bending without 

axial force 

N s = nominal capacity of the section in tension or 

compression without bending 

AS 4100 Ref. 

8.3.2 

8.3.3 

The effect of axial force can be ignored for doubly symmetric compact 

I-sections and rectangular and square hollow sections with k f = 1.0, if 

N 

* 

0.9 

N s 

N 

* 

0.9 

N s 

≤ 0.15 

≤ 0.40 

for bending about the major 

principal axis 

for bending about the minor 

principal axis 

The checking of section capacity is necessary for the combined action of uniaxial bending and axial 

tension because in Para. B3.1, the member capacity is enhanced with the presence of axial tension. 

The nominal capacity of a section in bending Ms = Ze fy as is specified in Para. 5.1.3. 

The nominal capacity of a section in tension Ns is the lesser of (Ag fy) and (0.85 kt An fu) as is specified in 

Chapter 7. 

The nominal capacity of a section in compression Ns = Ae fy as is specified in Para. 6.2. 


For doubly symmetric compact I sections and rectangular and square hollow sections with k f < 1.0, 

AS 4100 allows values of k between 1.0 and 1.18.

75 

B2.2 Section under biaxial bending and axial force (tension or compression) 

The interaction equation for a section subject to an axial load N * , a 

major axis bending moment M * 

x and a minor axis moment M * 

y is: 

where 

⎛ * 

⎜ N 

⎜ 0.9N 

⎝ 

s 

M 

* 

x 

+ 

0.9M 

sx 

M 

* 

y 

+ 

0.9M 

sy 

⎞ 

⎟ 

≤1.0 

⎟ 

⎠ 

N s = nominal capacity of the section under axial load 

M sx = nominal capacity of the section in bending about x- 

axis 

M sy = nominal capacity of the section bending about y-axis 

AS 4100 Ref. 

8.3.4 

The checking of section capacity for combined biaxial bending and axial force is necessary because a 

more generous allowance has been given to the member combined action capacity in Para. B3.2 and 

Para. B3.4. 

The nominal capacity of a section in tension Ns is the lesser of (A g f y) and (0.85 kt An fu) as specified in 

Chapter 7. 

The nominal capacity of a section in compression Ns = Ae fy as specified in Para. 6.2. 

The nominal capacity of a section in bending about x axis Msx = Zex fy and about y axis is Msy = Zey fy 

where Zex and Zey are the effective section moduli about x and y axes respectively. 

For doubly symmetric compact I sections with kf = 1.0 less conservative results can be obtained by using 

the alternative equations of Clause 8.3.4 of AS 4100 (as given in Fig. B1). 


76 

B3 

MEMBER CAPACITY UNDER COMBINED ACTIONS 

B3.1 Member under axial tension and uniaxial bending 

The interaction equation for a member subject to an axial tensile load 

N * and a principal axis bending moment M * is: 

⎛ * * ⎞ 

⎜ M N 

− ⎟ ≤1.0 

⎜ 0.9M 

0.9 ⎟ 

b N 

⎝ 

t 

⎠ 

where 

M b 

N t 

= nominal capacity of the member in bending 

= nominal capacity of the member in tension 

AS 4100 Ref. 

8.4.4.2 

The enhancement in bending capacity in the presence of axial tension (evident in the minus sign above) is 

available only for beams where bending capacities have been reduced because of lateral buckling 

problems. 

Mb = αs Ms as specified in Para. 5.1. 

N t is the lesser of (A g f y ) and (0.85 kt An fu) as specified in Chapter 7. 


B3.2 Member under axial tension and biaxial bending 

The interaction equation for a member subject to an axial tensile load 

N * , a major axis bending moment Mx * and a minor axis bending 

moment My * is 

where 

⎛ 

⎜ M 

x 

⎜ 0.9M 

⎝ 

⎛ * 

⎜ M 

y 

⎜ 0.9M 

⎝ 

⎞ 

⎟ 

⎟ 

⎠ 

* 1.4 

1. 4 

tx 

⎞ 

⎟ 

⎟ 

⎠ 

+ 

ry 

≤1.0 

M tx = 

⎛ ⎞ 

the lesser of ⎜ N 

* 

M 

⎟ 

sx 1 − and M 

⎜ 0.9N 

⎟ 

t 

⎝ ⎠ 

M ry = 

⎛ 

⎟ ⎟ ⎞ 

⎜ N 

* 

M sy 1 − 

⎜ 0.9N 

t 

⎝ ⎠ 

bx 

⎛ 

⎜1 

+ 

⎜ 

⎝ 

N 

* 

0.9N 

t 

⎞ 

⎟ 

⎟ 

⎠ 

AS 4100 Ref. 

8.4.5.2 

This Para. is applicable to members bent about a non-principal axis or bent about both principal axes. 

Nt is the lesser of (A g f y ) and (0.85 kt An fu) as specified in Chapter 7. 

M bx = αs Ms is the nominal capacity of the member in bending about its major principal axis.

77 

B3.3 Member under axial compression and uniaxial bending 

The interaction equation for a member subject to an axial compressive 

load N * and a principal axis bending moment M * is: 

where 

⎛ * 

⎜ N 

⎜ 0.9N 

⎝ 

M 

* 

+ 

0.9 

c M b 

⎞ 

⎟ ≤1.0 

⎟ 

⎠ 

M b = nominal capacity in bending of the member 

N c = nominal capacity in compression of the member 

M * = applied moment with moment amplification as 

determined in Para. 4.4.2 or Appendix A as 

applicable 

AS 4100 Ref. 

8.4.4.1 

For bending about the minor principal axis or for bending about the major principal axis without lateral 

buckling problems (αs = 1.0), the rule should be checked for in-plane action, i.e. with Nc as the 

compressive capacity for buckling about the same axis as the applied moment using ke = 1.0 for both 

braced or sway members. The member will need to be checked as a compression member in 

accordance with Para. 6.1 using the effective length l e as given in Para. 6.5. 

For bending about the major principal axis with lateral buckling problems (αs < 1.0), the rule should be 

checked twice, once for the in plane action (as above) and once for the out-of plane action, i.e. 

(a) In-plane action 

N c = N cx = the compressive capacity for buckling about the major principal axis using k e =1.0 

M b = M sx = the section capacity in bending about the major principal axis 

(b) Out-of-plane action 

N c = N cy = the compressive capacity for buckling about the minor principal axis using k e = 1.0 

M b = α s M sx = 

the member capacity in bending about the major principal axis (lateral buckling 

included) 

For doubly symmetric I sections with kf = 1.0 less conservative solutions can be obtained using the 

alternatives given in Clauses 8.4.2.2 and 8.4.4.1 of AS 4100. 


78 

B3.4 Member under axial compression and biaxial bending 

AS 4100 Ref. 

The interaction equation for a member subject to an axial compressive 8.4.5.1 

load N * * 

, a major axis bending moment M x and a minor axis moment 

* 

M y is: 

* 

* 

⎛ M ⎞ 1.4 ⎛ M ⎞ 1.4 

⎜ 

x ⎜ 

y 

⎟ + ⎟ 

≤1.0 

0.9 

⎜ 0.9 ⎟ 

⎝ M 

rbx ⎠ ⎝ 

M 

rby ⎠ 

where 

* 

M x , M 

* = applied moments with moment amplifications 

y 

determined in Para. 4.4.2 or Appendix A as 

applicable 

M rbx , M rby = reduced nominal capacity in bending of the 

member about the major and minor axis 

M rbx = 

⎛ ⎞ 

⎜ N 

* 

M 

⎟ 

bx 1 − 

⎜ 0.9N 

⎟ 

c 

⎝ ⎠ 

M rby = 

⎛ 

⎟ ⎟ ⎞ 

⎜ N 

* 

M by 1 − 

⎜ 0.9N 

c 

⎝ ⎠ 

For the major axis bending, Mrbx is the lesser value of the in-plane and out-of-plane capacities 

determined as follows: 

• for in-plane capacities: Nc is the member compressive capacity for buckling about the major 

principal axis using ke = 1.0 for both braced or sway members and Mbx = Msx = nominal capacity of 

section in bending about the major principal axis. The member will need to be checked as a 

compression member in accordance with Para. 6.1 using the effective length l e as given in 

Para. 6.5. 

• for out-of-plane capacities: Nc is the member compressive capacity for buckling about the minor 

principal axis and Mbx = αs Msx = nominal capacity in bending of the member about the major 

principal axis. 


For the minor axis bending Mrby is the minor principal axis in-plane member moment capacity and N c is 

the compressive capacity for buckling about the minor principal axis using ke = 1.0 for both braced and 

sway members and Mby = Msy = nominal capacity of section in bending about the minor principal axis. 

The interaction equation is plotted in Fig. B2. 

Fig. B3 illustrates in-plane and out-of-plane behaviour of a member under axial compression and 

bending. 

Fig. B4 summarizes all interaction equations for combined actions. These equations are exactly the same 

as those given in AS 4100 but cast in a different form.

79 

M X * 

0.9M SX 

Paragraph B.2.2 above 

1.0 

p = 0.0 

Clause 8.3.4 of AS4100 

0.8 

p = 0.3 

0.6 

p = 

N* 

0.9N s 

M Y * 

p = 0.6 

p = 0.0 

0.4 

p = 0.3 

0.2 

p = 0.9 

p = 0.6 

p = 0.9 

0.0 

0.0 0.2 0.4 0.6 0.8 1.0 

0.9M SY 


FIGURE B1 SECTION INTERACTION DIAGRAMS FOR COMBINED AXIAL 

COMPRESSION AND BIAXIAL BENDING FOR DOUBLY SYMMETRIC 

COMPACT SECTIONS

80 

M x * 

1.0 

0.8 

0.6 

0.9M bx 

M y * 

p = 0.0 

p = 0.1 

p = 0.2 

p = 0.3 

p = 0.4 

p = 0.5 

p = 

N* 

0.9N c 

0.4 

0.2 

0.0 

0.0 

0.2 

0.4 

0.6 

0.8 

1.0 

0.9M by 


FIGURE B2 MEMBER INTERACTION EQUATIONS FOR COMBINED AXIAL 

COMPRESSION AND BIAXIAL BENDING

81 

Z 

Z 

Z 

P 

P 

P 

M 

M 

M X 

M Y 

Lateral 

restraints 

l 

l 

Y 

Y 

Y 

P 

M 

X 

P 

M 

X 

P 

M X 

M Y 

X 

(a) In-plane behaviour 

(Column deflects in 

YZ plane only.) 

(b) Flexural-torsional buckling 

(Column deflects in YZ plane, 

then buckles by deflecting in 

XZ plane and twisting about Z.) 

(a) Biaxial bending 

(Column deflects in 

YZ and XZ planes 

and twists about Z.) 

FIGURE B3 BEAM-COLUMN BEHAVIOUR 



FIGURE B4 SUMMARY OF INTERACTION EQUATIONS FOR COMBINED ACTIONS 

Type of combined action Section capacity Member capacity 

Uniaxial bending and tension 

M * N * 

M * N * 

+ ≤ 1.0 

– ≤ 1.0 

0.9kM 

0.9N 

0.9M 

0.9N 

s t 

b t 

Uniaxial bending and compression 

M * 

+ 

0.9kM 

s 

Biaxial bending and tension 

N * 

+ 

0.9N t 

M * x 

+ 

0. 

9M sx 

Biaxial bending and compression N * M * + 

x 

+ 

0.9N s 

0.9M 

sx 

N * 

≤ 1.0 

0.9N 

s 

M * y 

≤ 1.0 

0.9M sy 

M * y 

≤ 1.0 

0.9M sy 

M * 

+ 

0.9M 

b 

⎛ M * ⎞ 

⎜ x ⎟ 

⎝ 

0.9M tx ⎠ 

⎛ M * ⎞ 

⎜ x ⎟ 

⎝ 

0.9M rbx ⎠ 

1.4 

1.4 

N * 

≤ 1.0 

0.9N 

c 

⎛ M ⎞ 

+ 

⎜ y ⎟ 

⎜ 0.9M ⎟ 

⎝ ry ⎠ 

* 1.4 

⎛ M ⎞ 

+ 

⎜ y ⎟ 

⎜ 0.9M ⎟ 

⎝ rby ⎠ 

* 1.4 

≤ 1.0 

≤ 1.0 

• M * , M * x, M * y are amplified applied bending moments 

82 

• N* = the applied axial force 

• Nt = the lesser of (Ag fy) and (0.85 kt An fu) 

• Mb = s Ms; Mbx = s Msx 

• Ms = Ze fy; Msx = Zex fy; Msy = Zey fy 

• Ns = kf An fy 

• k = 1.18 for compact I sections. 

= 1.0 for all other sections. 

• kt = correction factor for distribution of forces in a tension member 

• kf = form factor for members subject to axial compression 

• Nc = c Ns (see Note under Para. B3.3).


• Ncx = the compression capacity for buckling about the x-axis 

• Ncy = the compression capacity for buckling about the y-axis 

• Mrbx = 

• Mrby = 

⎛ 

⎞ ⎛ 

the lesser of ⎜ N * ⎟ ⎜ 

Msx 1 − and 

⎜ 0.9N 

⎟ 

Mbx⎜1 

− 

⎝ cx ⎠ 

⎝ 

⎛ 

⎞ 

⎜ N * ⎟ 

Msy ⎜1 

− ⎟ 

0.9N 

⎝ cy ⎠ 

⎛ ⎞ 

• Mtx = the lesser of ⎜ N * 

⎛ 

⎟ 

Msx 1 − and ⎜ 

⎜ 0.9N 

⎟ 

Mbx 1 + 

⎜ 

⎝ t ⎠ ⎝ 

⎛ 

• Mry = ⎜ Msy 1 − 

⎜ 

⎝ 

N * ⎞ 

⎟ 

0.9N 

⎟ 

t ⎠ 

N * ⎞ 

⎟ 

0.9N 

⎟ 

t ⎠ 

⎞ 

N * ⎟ 

0.9N 

⎟ 

cy 

⎠ 

83


84

PART II 

DESIGN AIDS 


CONNECTION DESIGN DATA 

D1 

BOLTS 

Loading condition 

Bolt grade 

DESIGN CAPACITY (kN) 

Bolt size 

M12 M16 M20 M24 M30 M36 

Bolt in Tension 4.6 27 50 78 113 179 260 

8.8 - 104 163 234 371 540 

Bolt in Shear, with 4.6 14 27 43 62 100 145 

Threads Included # 8.8 - 56 89 128 207 302 

Bolt in Shear, with 4.6 22 40 62 90 140 202 

Threads Excluded # 8.8 - 83 129 186 291 419 

Friction Grip * 8.8/TF - 23 36 52 82 - 


Plate thickness 

Bolt size 

(mm) 12 16 20 24 30 36 

Bolt Bearing 6 - 113 142 170 213 - 

for 250 steel plate 8 - 151 189 227 283 - 


10 - 189 236 283 254 - 

Plate thickness 

(mm) 

Edge distance 

(mm) 

35 40 45 

6 77 89 100 

Plate Tear out 8 103 118 133 

for 250 steel plateo 10 129 148 166 

12 155 177 199 

# capacity per interface 

* serviceability design capacity per interface for standard holes (kh = 1.0) 

° independent of bolt size 

FILLET WELDS 

D2 


Design capacity per unit length (kN/mm) 

Weld type Weld quality 

Weld size (mm) 

5 6 8 10 12 

E41/W40 GP 0.53 0.62 0.83 1.04 1.25 

SP 0.70 0.83 1.11 1.39 1.67 

E48/W50 GP 0.61 0.74 0.98 1.22 1.47 

SP 0.81 0.98 1.30 1.63 1.96


UNIVERSAL SECTION CAPACITIES—GRADE 300 

Axial Moment Shear Bearing 

Designation Ns Msx Msy Vx1 Vx2 Vx3 Rbb/bb Rby/bbf 

kN kNm kNm kN kN kN KN/mm KN/mm 

610UB125 3830 927 130 1103 905 753 1.07 4.02 

610UB113 3384 829 114 1038 847 701 0.92 3.78 

610UB101 3117 783 104 1048 851 700 0.81 3.82 

530UB92 2957 640 92 885 710 575 0.90 3.67 

530UB82 2557 559 78 833 664 535 0.77 3.46 

460UB82 2775 497 79 732 577 457 1.06 3.56 

460UB75 2437 448 62 673 528 417 0.86 3.28 

460UB67 2136 400 55 629 492 385 0.73 3.06 

410UB60 1935 324 47 514 394 301 0.70 2.81 

410UB54 1812 305 56 500 382 290 0.65 2.74 

360UB57 1947 273 45 460 346 256 0.91 2.88 

360UB51 1682 242 38 420 314 231 0.72 2.63 

360UB45 1532 222 47 397 294 214 0.63 2.48 

310UB46 1587 197 38 329 237 166 0.74 2.41 

310UB40 1428 182 25 299 215 149 0.59 2.20 

310UB32 1075 134 33 268 190 129 0.46 1.98 

250UB37 1368 140 33 259 177 NR 0.86 2.30 

250UB31 1155 114 26 247 167 NR 0.77 2.20 

250UB26 894 92 18 200 135 NR 0.48 1.80 

200UB30 1100 91 25 205 128 NR 1.06 2.27 

200UB25 930 75 20 188 116 NR 0.90 2.09 

200UB22 827 65 17 162 100 NR 0.65 1.80 

200UB18 661 52 10 143 87 NR 0.52 1.62 

180UB22 812 56 12 165 96 NR 1.12 2.16 

180UB18 662 45 9 137 78 NR 0.79 1.80 

180UB16 588 40 8 124 70 NR 0.63 1.62 

150UB18 662 39 8 141 74 NR 1.24 2.16 

150UB14 513 29 6 118 60 NR 0.91 1.80 

310UC158 5065 675 305 705 536 406 3.47 5.30 

310UC137 4410 580 262 619 466 346 2.90 4.66 

310UC118 3780 494 222 534 397 289 2.32 4.02 

310UC97 3348 421 187 474 347 247 1.76 3.56 

250UC90 2873 310 143 408 287 NR 2.24 3.78 

250UC73 2516 266 123 334 231 NR 1.62 3.10 

200UC60 2057 177 81 291 187 NR 2.08 3.35 

200UC52 1798 154 70 250 158 NR 1.66 2.88 

200UC46 1593 133 60 228 143 NR 1.43 2.63 

150UC37 1277 84 37 195 107 NR 1.90 2.92 

150UC30 1112 72 32 159 85 NR 1.42 2.38 

150UC23 858 51 21 147 75 NR 1.26 2.20 

100UC15 544 21 10 72 NR NR 1.19 1.80 

Vx1 = design shear capacity for uncoped web. 

Vx2 = design shear capacity for single coped web. (standard cope = 65 mm) 

Vx3 = design shear capacity for double coped web. (standard cope = 65 mm) 

D3


UNIVERSAL SECTION CAPACITIES—GRADE 350 




610UB125 4485 1126 158 1250 1026 853 1.11 4.55 

610UB113 3953 1007 138 1176 960 795 0.95 4.28 

610UB101 3449 887 118 1179 958 788 0.83 4.29 

530UB92 3275 725 105 995 798 647 0.93 4.13 

530UB82 2827 633 88 937 747 602 0.79 3.89 

460UB82 3072 563 89 824 649 514 1.1 4.01 

460UB75 2698 508 70 757 594 469 0.89 3.69 

460UB67 2366 453 62 707 553 434 0.74 3.44 

410UB60 2146 367 53 578 443 339 0.72 3.16 

410UB54 1996 340 63 563 430 327 0.67 3.08 

360UB57 2158 309 51 518 389 288 0.94 3.24 

360UB51 1867 274 43 473 353 260 0.75 2.96 

360UB45 1688 247 53 447 331 241 0.65 2.79 

310UB46 1764 223 42 370 267 187 0.76 2.71 

310UB40 1580 204 28 337 241 167 0.6 2.47 

310UB32 1187 150 38 302 214 145 0.47 2.23 

250UB37 1539 157 38 291 199 NR 0.9 2.59 

250UB31 1288 127 29 277 188 NR 0.8 2.47 

250UB26 987 103 20 226 151 NR 0.5 2.03 

200UB30 1238 102 28 230 144 NR 1.12 2.55 

200UB25 1047 83 22 212 131 NR 0.94 2.35 

200UB22 930 73 19 183 112 NR 0.67 2.03 

200UB18 729 58 11 161 98 NR 0.54 1.82 

180UB22 914 63 13 185 108 NR 1.2 2.43 

180UB18 745 51 11 155 88 NR 0.83 2.03 

180UB16 661 45 9 139 79 NR 0.66 1.82 

150UB18 745 44 9 159 84 NR 1.35 2.43 

150UB14 577 33 6 132 67 NR 0.97 2.03 

310UC158 6151 820 370 798 608 460 3.84 6.01 

310UC137 5355 704 318 702 528 392 3.19 5.28 

310UC118 4590 597 270 605 450 327 2.53 4.55 

310UC97 3794 474 212 533 390 277 1.88 4.01 

250UC90 3488 376 174 459 323 NR 2.44 4.25 

250UC73 2852 299 139 376 260 NR 1.73 3.48 

200UC60 2332 201 91 327 210 NR 2.28 3.77 

200UC52 2038 174 80 281 178 NR 1.8 3.24 

200UC46 1805 150 68 257 160 NR 1.54 2.96 

150UC37 1447 95 42 219 120 NR 2.1 3.28 

150UC30 1251 80 36 178 95 NR 1.55 2.67 

150UC23 966 56 24 165 85 NR 1.37 2.47 

100UC15 612 24 11 81 NR NR 1.31 2.03 

Vx1 = design shear capacity for uncoped web. 

Vx2 = design shear capacity for single coped web. (standard cope = 65 mm) 

Vx3 = design shear capacity for double coped web. (standard cope = 65 mm) 

D4


WELDED SECTION CAPACITIES—GRADE 300 




1200WB455 12140 7106 1260 2903 2526 2246 0.78 5.40 

1200WB423 11124 6502 1134 2903 2517 2230 0.78 5.40 

1200WB392 10123 5897 1008 2903 2508 2213 0.78 5.40 

1200WB342 8507 4990 645 2903 2508 2213 0.78 5.40 

1200WB317 7698 4511 564 2903 2498 2196 0.78 5.40 

1200WB278 6468 3780 386 2903 2491 2184 0.78 5.40 

1200WB249 5528 3251 239 2903 2491 2184 0.78 5.40 

1000WB322 8524 4133 645 2488 2138 1877 1.02 5.40 

1000WB296 7716 3730 564 2488 2129 1860 1.02 5.40 

1000WB258 6475 3100 386 2488 2122 1848 1.02 5.40 

1000WB215 5460 2584 244 2488 2111 1827 1.02 5.40 

900WB282 7590 3427 645 1728 1479 1292 0.57 4.18 

900WB257 6782 3074 564 1728 1471 1279 0.57 4.18 

900WB218 5548 2510 386 1728 1466 1269 0.57 4.18 

900WB175 4456 2025 243 1728 1457 1253 0.57 4.18 

800WB192 5024 2016 318 1272 1077 930 0.43 3.49 

800WB168 4266 1709 238 1272 1073 922 0.43 3.49 

800WB146 3817 1534 204 1272 1065 908 0.43 3.49 

800WB122 3007 1215 134 1272 1059 898 0.43 3.49 

700WB173 4674 1610 267 1105 928 795 0.54 3.49 

700WB150 3942 1353 197 1105 924 786 0.54 3.49 

700WB130 3550 1212 169 1105 916 773 0.54 3.49 

700WB115 3008 1023 134 1105 910 762 0.54 3.49 

500WC440 14112 2621 1263 2419 2019 1715 9.42 12.60 

500WC414 13306 2545 1263 1935 1615 1372 7.27 10.10 

500WC383 12298 2301 1137 1935 1598 1340 7.27 10.10 

500WC340 10886 2263 1008 1701 1403 1176 5.18 7.88 

500WC290 9324 1908 859 1458 1191 987 3.97 6.75 

500WC267 8568 1688 748 1458 1182 971 3.97 6.75 

500WC228 7830 1407 594 1458 1168 945 3.97 6.75 

400WC361 11592 1880 809 2117 1749 1470 9.59 12.60 

400WC328 10534 1789 806 1482 1225 1029 6.36 8.82 

400WC303 9727 1618 726 1482 1209 1001 6.36 8.82 

400WC270 8669 1426 645 1323 1066 870 5.55 7.88 

400WC212 6804 1099 504 1134 894 709 4.43 6.75 

400WC181 6210 921 408 1134 879 682 4.43 6.75 

400WC144 4968 699 302 907 694 529 3.23 5.40 

350WC280 8996 1245 617 1164 942 772 6.61 8.82 

350WC258 8291 1121 557 1164 927 744 6.61 8.82 

350WC230 7384 985 494 1040 814 640 5.81 7.88 

350WC197 6325 844 433 891 686 528 4.74 6.75 

φ Vx1 = design shear capacity for uncoped web. 

φ Vx2 = design shear capacity for single coped web. (standard cope = 65 mm) 

φ Vx3 = design shear capacity for double coped web. (standard cope = 65 mm) 

D5


WELDED SECTION CAPACITIES—GRADE 400 


Designation φ Ns φ Msx φ Msy φ Vx1 φ Vx2 φ Vx3 φ Rbb/bb φ Rby/bbf 


1200WB455 15308 9040 1620 3677 3200 2846 0.81 6.84 

1200WB423 14006 8262 1458 3677 3188 2824 0.81 6.84 

1200WB392 12724 7484 1264 3677 3176 2803 0.81 6.84 

1200WB342 10641 6318 829 3677 3176 2803 0.81 6.84 

1200WB317 9610 5702 723 3677 3165 2782 0.81 6.84 

1200WB278 8017 4795 496 3677 3156 2766 0.81 6.84 

1200WB249 6820 4082 307 3677 3156 2766 0.81 6.84 

1000WB322 10654 5314 829 3152 2709 2377 1.06 6.84 

1000WB296 9626 4795 726 3152 2697 2356 1.06 6.84 

1000WB258 8037 3985 496 3152 2688 2340 1.06 6.84 

1000WB215 6597 3273 303 3152 2674 2314 1.06 6.84 

900WB282 9584 4309 829 2229 1908 1667 0.58 5.40 

900WB257 8539 3856 723 2229 1899 1650 0.58 5.40 

900WB218 6954 3140 496 2229 1892 1638 0.58 5.40 

900WB175 5461 2483 302 2229 1880 1617 0.58 5.40 

800WB192 6340 2505 408 1642 1390 1200 0.44 4.50 

800WB168 5367 2119 307 1642 1384 1190 0.44 4.50 

800WB146 4707 1867 259 1642 1375 1172 0.44 4.50 

800WB122 3681 1471 166 1642 1367 1158 0.44 4.50 

700WB173 5888 2070 343 1426 1198 1025 0.56 4.50 

700WB150 4945 1740 253 1426 1192 1015 0.56 4.50 

700WB130 4366 1529 214 1426 1182 997 0.56 4.50 

700WB115 3680 1289 166 1426 1175 983 0.56 4.50 

500WC440 18144 3370 1623 3110 2595 2204 11.90 16.20 

500WC414 17107 3272 1623 2488 2076 1764 9.10 13.00 

500WC383 15811 2958 1461 2488 2054 1723 9.10 13.00 

500WC340 13997 2861 1270 2187 1804 1512 6.35 10.10 

500WC290 11988 2401 1072 1847 1509 1250 4.68 8.55 

500WC267 11016 2119 927 1847 1498 1230 4.68 8.55 

500WC228 9561 1662 718 1847 1479 1197 4.68 8.55 

400WC361 14904 2417 1040 2722 2249 1890 12.10 16.20 

400WC328 13543 2300 1037 1905 1574 1323 7.97 11.30 

400WC303 12506 2080 933 1905 1555 1287 7.97 11.30 

400WC270 11146 1834 829 1701 1371 1118 6.91 10.10 

400WC212 8748 1383 632 1436 1132 898 5.36 8.55 

400WC181 7866 1139 499 1436 1114 864 5.36 8.55 

400WC144 6066 824 366 1149 880 670 3.82 6.84 

350WC280 11567 1601 794 1497 1211 992 8.34 11.30 

350WC258 10660 1442 716 1497 1192 957 8.34 11.30 

350WC230 9493 1267 635 1337 1047 823 7.30 10.10 

350WC197 8132 1085 557 1129 869 668 5.82 8.55 

φVx1 = design shear capacity for uncoped web. 

φVx2 = design shear capacity for single coped web. (standard cope = 65 mm) 

φVx3 = design shear capacity for double coped web. (standard cope = 65 mm) 

D6

D7 

UNIVERSAL BEAMS—GRADE 300 

1000 

Y 

Section I x I y 

610UB125 

X10 6 mm 4 X10 6 mm 4 

900 

800 

610UB113 

610UB101 

X 

Y 

X 

610 UB 125 986 39.3 

610 UB 113 875 34.3 

610 UB 101 761 29.3 

530 UB 92 554 23.8 

530 UB 82 477 20.1 

700 

530UB92 

460 UB 82 372 18.6 

460 UB 75 335 16.6 

460 UB 67 296 14.5 

410 UB 60 216 12.1 

410 UB 54 188 10.3 

600 

530UB82 

500 

460UB82 

460UB75 

φ 

400 

460UB67 

300 

410UB60 

410UB54 

200 


100 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m)

D8 


300 

360UB57 

Y 


X10 6 mm 4 X10 6 mm 4 

250 

200 

360UB51 

360UB45 

310UB46 

X 

Y 

X 

360 UB 57 161 11.0 

360 UB 51 142 9.60 

360 UB 45 121 8.10 

310 UB 46 100 9.01 

310 UB 40 86.4 7.65 

310 UB 32 63.2 4.42 

250 UB 37 55.7 5.66 

250 UB 31 44.5 4.47 

250 UB 26 35.4 2.55 

310UB40 

150 

310UB32 

φ 

250UB37 

250UB31 

100 

250UB26 


50 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m) 

310UB46 

360UB45

D9 

100 

90 

80 

70 

200UB30 

200UB25 

200UB22 


X 

Y 

Y 

X 


X10 6 mm 4 X10 6 mm 4 

200 UB 30 29.1 3.86 

200 UB 25 23.6 3.06 

200 UB 22 21.0 2.75 

200 UB 18 15.8 1.14 

180 UB 22 15.3 1.22 

180 UB 18 12.1 0.975 

180 UB 16 10.6 0.853 

150 UB 18 9.05 0.672 

150 UB 14 6.66 0.495 

60 

50 

200UB18 

180UB22 

180UB18 

φ 

40 

180UB16 

150UB18 

30 

150UB14 

20 


10 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m) 

180UB16

D10 


1200 

610UB125 

Y 


X10 6 mm 4 X10 6 mm 4 

1100 

1000 

610UB113 

X 

Y 

X 

610 UB 125 986 39.3 

610 UB 113 875 34.3 

610 UB 101 761 29.3 

530 UB 92 554 23.8 

530 UB 82 477 20.1 

900 

610UB101 

460 UB 82 372 18.6 

460 UB 75 335 16.6 

460 UB 67 296 14.5 

800 

410 UB 60 216 12.1 

410 UB 54 188 10.3 

530UB92 

700 

530UB82 

600 

460UB82 

φ 

500 

460UB75 

460UB67 

400 

410UB60 

300 

410UB54 

200 


100 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m)

D11 


350 

Y 


X10 6 mm 4 X10 6 mm 4 

300 

360UB57 

X 

X 

360 UB 57 161 11.0 

360 UB 51 142 9.60 

360 UB 45 121 8.10 

360UB51 

Y 

310 UB 46 100 9.01 

310 UB 40 86.4 7.65 

310 UB 32 63.2 4.42 

250 

360UB45 

310UB46 

250 UB 37 55.7 5.66 

250 UB 31 44.5 4.47 

250 UB 26 35.4 2.55 

200 

310UB40 

310UB32 

φ 

150 

250UB37 

250UB31 

100 

250UB26 


50 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m) 

310UB46 

360UB45

D12 

110 

200UB30 


Y 


X10 6 mm 4 X10 6 mm 4 

100 

90 

200UB25 

X 

Y 

X 

200 UB 30 29.1 3.86 

200 UB 25 23.6 3.06 

200 UB 22 21.0 2.75 

200 UB 18 15.8 1.14 

180 UB 22 15.3 1.22 

180 UB 18 12.1 0.975 

180 UB 16 10.6 0.853 

80 

200UB22 

150 UB 18 9.05 0.672 

150 UB 14 6.66 0.495 

70 

200UB18 

60 

180UB22 

φ 

50 

180UB18 

180UB16 

40 

150UB18 

30 

150UB14 

20 


10 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m) 

180UB16

D13 

UNIVERSAL COLUMNS—GRADE 300 

700 

310UC158 

600 

310UC137 

500 

310UC118 

310UC97 

400 

φ 

300 

250UC90 

250UC73 

200 


X10 6 mm 4 X10 6 mm 4 

Y 


100 

0 

310 UC 158 388 125 

310 UC 137 329 107 

310 UC 118 277 90.2 

310 UC 97 223 72.9 

250 UC 90 143 48.4 

250 UC 73 114 38.8 

X 

Y 

X 

0 1 2 3 4 5 6 7 8 9 10 

l e (m)

D14 


180 

170 

200UC60 

Y 


X10 6 mm 4 X10 6 mm 4 

160 

200UC52 

X 

X 

200 UC 60 61.3 20.4 

200 UC 52 52.8 17.7 

200 UC 46 45.9 15.3 

150 

140 

130 

200UC46 

Y 

150 UC 37 22.2 7.01 

150 UC 30 17.6 5.62 

150 UC 23 12.6 3.98 

100 UC 15 3.18 1.14 

120 

110 

100 

90 

150UC37 

φ 

80 

70 

150UC30 

60 

50 

150UC23 

40 

30 


20 

10 

0 

100UC15 

0 1 2 3 4 5 6 7 8 9 10 

l e (m)

D15 


900 

310UC158 

Y 


X10 6 mm 4 X10 6 mm 4 

800 

X 

X 

310 UC 158 388 125 

310 UC 137 329 107 

310 UC 118 277 90.2 

310 UC 97 223 72.9 

700 

310UC137 

Y 

250 UC 90 143 48.4 

250 UC 73 114 38.8 

600 

310UC118 

500 

310UC97 

φ 

400 

250UC90 

300 

250UC73 

200 


100 

0 

0 1 2 3 4 5 6 7 8 9 10 

l e (m)

D16 


210 

200 

200UC60 

Y 


X10 6 mm 4 X10 6 mm 4 

190 

180 

170 

160 

150 

200UC52 

200UC46 

X 

Y 

X 

200 UC 60 61.3 20.4 

200 UC 52 52.8 17.7 

200 UC 46 45.9 15.3 

150 UC 37 22.2 7.01 

150 UC 30 17.6 5.62 

150 UC 23 12.6 3.98 

100 UC 15 3.18 1.14 

140 

130 

120 

110 

100 

150UC37 

φ 

90 

80 

70 

60 

50 

40 

150UC30 

150UC23 


30 

20 

10 

0 

100UC15 

0 1 2 3 4 5 6 7 8 9 10 

l e (m)

D17 

WELDED BEAMS—GRADE 300 

8000 

Y 


X10 6 mm 4 X10 6 mm 4 

7000 

1200WB455 

1200WB423 

X 

Y 

X 

1200 WB 455 15300 834 

1200 WB 423 13900 750 

1200 WB 392 12500 667 

1200 WB 342 10400 342 

1200 WB 317 9250 299 

6000 

1200WB392 

1000 WB 322 7480 342 

1000 WB 296 6650 299 

1000 WB 258 5430 179 

900 WB 282 5730 341 

900 WB 257 5050 299 

900 WB 218 4060 179 

5000 

1200WB342 

800 WB 192 2970 126 

1200WB317 

700 WB 173 2060 97.1 

700 WB 150 1710 65.2 

1000WB322 

4000 

1000WB296 

φ 

900WB282 

3000 

1000WB258 

900WB257 

900WB218 

2000 

800WB192 

700WB173 


1000 

0 

700WB150 

900WB257 

1000WB258 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

D18 


4000 

1200WB278 

Y 


X10 6 mm 4 X10 6 mm 4 

3500 

X 

X 

1200 WB 278 7610 179 

1200 WB 249 6380 87.0 

1200WB249 

Y 

1000 WB 215 4060 90.3 

900 WB 175 2960 90.1 

3000 

800 WB 168 2480 86.7 

800 WB 146 2040 69.4 

800 WB 122 1570 41.7 

1000WB215 

700 WB 130 1400 52.1 

700 WB 115 1150 41.7 

2500 

2000 

900WB175 

φ 

800WB168 

1500 

800WB146 

800WB122 

700WB130 

1000 

700WB115 


500 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m) 

700WB130

D19 


10000 

Y 


X10 6 mm 4 X10 6 mm 4 

9000 

1200 WB 455 

1200 WB 423 

X 

Y 

X 

1200 WB 455 15300 834 

1200 WB 423 13900 750 

1200 WB 392 12500 667 

1200 WB 342 10400 342 

1200 WB 317 9250 299 

8000 

1200 WB 392 

1000 WB 322 7480 342 

1000 WB 296 6650 299 

1000 WB 258 5430 179 

7000 

1200 WB 342 

900 WB 282 5730 341 

900 WB 257 5050 299 

900 WB 218 4060 179 

800 WB 192 2970 126 

6000 

1200 WB 317 

700 WB 173 2060 97.1 

700 WB 150 1710 65.2 

1000 WB 322 

5000 

1000 WB 296 

φ 

900 WB 282 

4000 

1000 WB 258 

900 WB 257 

900 WB 218 

3000 

800 WB 192 

2000 

700 WB 173 


1000 

0 

700 WB 150 

900WB257 

1000WB258 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

D20 

5000 

1200 WB 278 


Y 


X10 6 mm 4 X10 6 mm 4 

4500 

X 

X 

1200 WB 278 7610 179 

1200 WB 249 6380 87.0 

1200 WB 249 

1000 WB 215 4060 90.3 

4000 

Y 

900 WB 175 2960 90.1 

3500 

800 WB 168 2480 86.7 

800 WB 146 2040 69.4 

800 WB 122 1570 41.7 

1000 WB 215 

700 WB 130 1400 52.1 

700 WB 115 1150 41.7 

3000 

2500 

900 WB 175 

φ 

800 WB 168 

2000 

800 WB 146 

1500 

700 WB 130 

800 WB 122 

700 WB 115 

1000 


500 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

D21 

3000 

WELDED COLUMNS—GRADE 300 

500 WC 440 

2500 

500 WC 414 

500 WC 383 

500 WC 340 

2000 

400 WC 361 

400 WC 328 

500 WC 267 

1500 

500 WC 228 

φ 

350 WC 258 

1000 


X10 6 mm 4 X10 6 mm 4 


500 

0 

500 WC 440 2150 835 

500 WC 414 2110 834 

500 WC 383 1890 751 

500 WC 340 2050 667 

500 WC 267 1560 521 

500 WC 228 1260 417 

400 WC 361 1360 429 

400 WC 328 1320 427 

350 WC 258 661 258 

X 

Y 

Y 

X 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

D22 


2000 

500 WC 290 

Y 


X10 6 mm 4 X10 6 mm 4 

1800 

X 

X 

500 WC 290 1750 584 

1600 

400 WC 303 

Y 

400 WC 303 1180 385 

400 WC 270 1030 342 

400 WC 212 776 267 

400 WC 181 620 214 

400 WC 144 486 171 

1400 

400 WC 270 

350 WC 280 747 286 

350 WC 230 573 229 

350 WC 197 486 200 

350 WC 280 

1200 

400 WC 212 

1000 

350 WC 230 

400 WC 181 

φ 

350 WC 197 

800 

400 WC 144 

600 

400 


200 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

D23 


3500 

500 WC 440 

500 WC 414 

3000 

500 WC 383 

500 WC 340 

2500 

400 WC 361 

400 WC 328 

2000 

500 WC 267 

500 WC 228 

φ 

1500 

350 WC 258 

1000 


X10 6 mm 4 X10 6 mm 4 


500 

0 

500 WC 440 2150 835 

500 WC 414 2110 834 

500 WC 383 1890 751 

500 WC 340 2050 667 

500 WC 267 1560 521 

500 WC 228 1260 417 

400 WC 361 1360 429 

400 WC 328 1320 427 

350 WC 258 661 258 

X 

Y 

Y 

X 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

D24 

2600 

2400 

2200 

2000 

1800 

500 WC 290 

400 WC 303 

400 WC 270 


X 

Y 

Y 

X 


X10 6 mm 4 X10 6 mm 4 

500 WC 290 1750 584 

400 WC 303 1180 385 

400 WC 270 1030 342 

400 WC 212 776 267 

400 WC 181 620 214 

400 WC 144 486 171 

350 WC 280 747 286 

350 WC 230 573 229 

350 WC 197 486 200 

1600 

350 WC 280 

1400 

400 WC 212 

φ 

1200 

350 WC 230 

400 WC 181 

1000 

350 WC 197 

800 

400 WC 144 

600 

400 


200 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

l e (m)

PART III 

WORKED EXAMPLES 


INTRODUCTION TO THE WORKED EXAMPLES 

This part of the Handbook offers a series of sample computations to demonstrate the 

application of the simplified design rules and design aids found in Part I and Part II. 

The examples have been derived from actual designs, but have been simplified to 

demonstrate particular aspects of design problems rather than to provide solutions to 

complete design tasks. 

All examples follow a common format, which includes: 

(i) a statement of the problem, including the geometry of the structure, and its loading, 

(ii) proposed solutions 

(iii) commentary on the solutions offered (in selected instances) 

The alternative solutions make varying use of the design aids and demonstrate different 

‘tiers’ of design methodology in some instances. 

References to the appropriate paragraph of the Handbook are given in the right-hand 

margin. 

All problems are solved using only this Handbook, a booklet of section properties, and a 

rudimentary hand-held calculator. Most of the computations are strength checks, this 

being the area on which the Handbook has concentrated. The loads are calculated with 

the appropriate load factors. In some instances, a serviceability Limit State is also 

checked as a reminder that, in Limit States Design, both types of Limit States must be 

designed for. 

The computations have been carried out with a degree of accuracy appropriate to a 

lower tier design.

HB48-1999 Steel structures design handbook

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