As4100

AS 4100—1998 (Incorporating Amendment No. 1)

Australian Standard ®

Steel structures

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This Australian Standard® was prepared by Committee BD-001, Steel Structures. It was

approved on behalf of the Council of Standards Australia on 17 April 1998.

This Standard was published on 5 June 1998.

The following are represented on Committee BD-001:

• Association of Consulting Engineers Australia • Australian Construction Services • Australian Institute of Steel Construction • AUSTROADS • Building Management Authority, W.A. • Bureau of Steel Manufacturers of Australia • CSIRO, Division of Building, Construction and Engineering • Confederation of Australian Industry • Institution of Engineers, Australia • Metal Trades Industry Association of Australia • New Zealand Heavy Engineering Research Association • Public Works Department, N.S.W. • Railways of Australia Committee • University of New South Wales • University of Queensland • University of Sydney • Welding Technology Institute of Australia

This Standard was issued in draft form for comment as DR 97347.

Standards Australia wishes to acknowledge the participation of the expert individuals that

contributed to the development of this Standard through their representation on the

Committee and through the public comment period.

Keeping Standards up-to-date Australian Standards® are living documents that reflect progress in science, technology and

systems. To maintain their currency, all Standards are periodically reviewed, and new editions

are published. Between editions, amendments may be issued.

Standards may also be withdrawn. It is important that readers assure themselves they are

using a current Standard, which should include any amendments that may have been

published since the Standard was published.

Detailed information about Australian Standards, drafts, amendments and new projects can

be found by visiting www.standards.org.au

Standards Australia welcomes suggestions for improvements, and encourages readers to

notify us immediately of any apparent inaccuracies or ambiguities. Contact us via email at

mail@standards.org.au, or write to Standards Australia, GPO Box 476, Sydney, NSW 2001.

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AS 4100—1998 (Incorporating Amendment No. 1 )

Australian Standard ®

Steel structures

Originated in part as SAA INT 351—1956. Previous edition AS 4100—1990.

Second edition 1998. Reissued incorporating Amendment No. 1 (February 2012).

COPYRIGHT

© Standards Australia Limited

All rights are reserved. No part of this work may be reproduced or copied in any form or by

any means, electronic or mechanical, including photocopying, without the written

permission of the publisher, unless otherwise permitted under the Copyright Act 1968.

Published by SAI Global Limited under licence from Standards Australia Limited, GPO Box

476, Sydney, NSW 2001, Australia

ISBN 0 7337 1981 3

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AS 4100—1998 2

PREFACE

This Standard was prepared by the Standards Australia Committee BD-001, Steel Structures, to supersede AS 4100—1990.

This Standard incorporates Amendment No. 1 (February 2012). The changes required by

the Amendment are indicated in the text by a marginal bar and amendment number against

the clause, note, table, figure or part thereof affected.

The objective of this Standard is to provide designers of steel structures with specifications for steel structural members used for load-carrying purposes in buildings and other structures.

This new edition of the Standard incorporates Amendments No. 1—1992, No. 2—1993, No. 3—1995 and draft Amendment No. 4 issued for public comment as DR 97347. Draft Amendment No. 4 was not published separately as a green slip.

Amendment No. 1—1992 includes the following major changes:

(a) Strength of steels complying with AS 1163 and AS/NZS 1594. (Table 2.1.)

(b) Shear buckling capacity for stiffened web. (Clause 5.11.5.2.)

(c) Bearing buckling capacity. (Clause 5.13.4.)

Amendment No. 2—1993 includes the following major changes:

(a) Shear and bending interaction method. (Clause 5.12.3.)

(b) Minimum area for the design of intermediate transverse web stiffeners. (Clause 5.15.3.)

(c) Section capacity of members subject to combined actions. (Clause 8.3.)

(d) Strength assessment of a butt weld. (Clause 9.7.2.7.)

(e) Fatigue. (Section 11.)

Amendment No. 3—1993 includes the following major changes:

(a) Compressive bearing action on the edge of a web. (Clause 5.13.)

(b) Section capacity of members subject to combined actions. (Clause 8.3.)

(c) In-plane and out-of-plane capacity of compression members. (Clauses 8.4.2.2 and 8.4.41.)

(d) Strength assessment of a butt weld. (Clause 9.7.2.7.)

(e) Earthquake. (Section 13.)

Amendment No. 4 includes the following major changes:

(a) Strengths of steels complying with AS/NZS 3678, AS/NZS 3679.1 and AS/NZS 3679.2. (Table 2.1.)

(b) Minimum edge distance of fasteners. (Clause 9.6.2.)

(c) Permissible service temperatures according to steel type and thickness. (Table 10.4.1.)

(d) Steel type relationship to steel grade. (Table 10.4.4.)

(e) Welding of concentrically braced frames for structures of earthquake Design Category D and E. (Clause 13.3.4.2.)

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3 AS 4100—1998

Amendment No. 1—2012 to the 1998 edition includes the following major changes:

(a) Revisions to AS/NZS 1163, AS/NZS 3678, AS/NZS 3679.1 and AS/NZS 3679.2 reflected by amendments to Sections 2 and 10.

(b) Revisions to AS/NZS 1554.1, AS/NZS 1554.4 and AS/NZS 1554.5 reflected by amendments to Sections 9 and 10.

(c) Section 13 brought into line with revisions to AS 1170.4.

(d) Quenched and tempered steels included by adding ‘AS 3597’ to listed material Standards in Section 2.

(e) Typographical errors corrected.

The terms ‘normative’ and ‘informative’ have been used in this Standard to define the application of the appendix to which they apply. A ‘normative’ appendix is an integral part of a Standard, whereas an ‘informative’ appendix is only for information and guidance.

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AS 4100—1998 4

CONTENTS

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SECTION 1 SCOPE AND GENERAL 1.1 SCOPE AND APPLICATION ..................................................................................... 8 1.2 REFERENCED DOCUMENTS ................................................................................... 8 1.3 DEFINITIONS ............................................................................................................. 8 1.4 NOTATION ............................................................................................................... 12 1.5 USE OF ALTERNATIVE MATERIALS OR METHODS ........................................ 24 1.6 DESIGN .................................................................................................................... 24 1.7 CONSTRUCTION ..................................................................................................... 24

SECTION 2 MATERIALS 2.1 YIELD STRESS AND TENSILE STRENGTH USED IN DESIGN .......................... 25 2.2 STRUCTURAL STEEL ............................................................................................. 25 2.3 FASTENERS ............................................................................................................. 25 2.4 STEEL CASTINGS ................................................................................................... 27

SECTION 3 GENERAL DESIGN REQUIREMENTS 3.1 DESIGN .................................................................................................................... 30 3.2 LOADS AND OTHER ACTIONS ............................................................................. 30 3.3 STABILITY LIMIT STATE ...................................................................................... 31 3.4 STRENGTH LIMIT STATE ...................................................................................... 31 3.5 SERVICEABILITY LIMIT STATE .......................................................................... 32 3.6 STRENGTH AND SERVICEABILITY LIMIT STATES BY LOAD TESTING ...... 33 3.7 BRITTLE FRACTURE .............................................................................................. 34 3.8 FATIGUE .................................................................................................................. 34 3.9 FIRE .......................................................................................................................... 34 3.10 EARTHQUAKE ........................................................................................................ 34 3.11 OTHER DESIGN REQUIREMENTS ........................................................................ 34

SECTION 4 METHODS OF STRUCTURAL ANALYSIS 4.1 METHODS OF DETERMINING ACTION EFFECTS ............................................. 35 4.2 FORMS OF CONSTRUCTION ASSUMED FOR STRUCTURAL ANALYSIS ...... 35 4.3 ASSUMPTIONS FOR ANALYSIS ........................................................................... 36 4.4 ELASTIC ANALYSIS ............................................................................................... 37 4.5 PLASTIC ANALYSIS ............................................................................................... 42 4.6 MEMBER BUCKLING ANALYSIS ......................................................................... 43 4.7 FRAME BUCKLING ANALYSIS ............................................................................ 47

SECTION 5 MEMBERS SUBJECT TO BENDING 5.1 DESIGN FOR BENDING MOMENT ....................................................................... 49 5.2 SECTION MOMENT CAPACITY FOR BENDING ABOUT A PRINCIPAL

AXIS .......................................................................................................................... 50 5.3 MEMBER CAPACITY OF SEGMENTS WITH FULL LATERAL RESTRAINT ... 52 5.4 RESTRAINTS ........................................................................................................... 54 5.5 CRITICAL FLANGE ................................................................................................. 58 5.6 MEMBER CAPACITY OF SEGMENTS WITHOUT FULL LATERAL

RESTRAINT ............................................................................................................. 58 5.7 BENDING IN A NON-PRINCIPAL PLANE ............................................................ 65 5.8 SEPARATORS AND DIAPHRAGMS ...................................................................... 65 5.9 DESIGN OF WEBS ................................................................................................... 66 A

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5.10 ARRANGEMENT OF WEBS ................................................................................... 66 5.11 SHEAR CAPACITY OF WEBS ................................................................................ 68 5.12 INTERACTION OF SHEAR AND BENDING ......................................................... 71 5.13 COMPRESSIVE BEARING ACTION ON THE EDGE OF A WEB ........................ 72 5.14 DESIGN OF LOAD BEARING STIFFENERS ......................................................... 77 5.15 DESIGN OF INTERMEDIATE TRANSVERSE WEB STIFFENERS ...................... 78 5.16 DESIGN OF LONGITUDINAL WEB STIFFENERS ............................................... 80

SECTION 6 MEMBERS SUBJECT TO AXIAL COMPRESSION 6.1 DESIGN FOR AXIAL COMPRESSION ................................................................... 81 6.2 NOMINAL SECTION CAPACITY ........................................................................... 81 6.3 NOMINAL MEMBER CAPACITY .......................................................................... 83 6.4 LACED AND BATTENED COMPRESSION MEMBERS ....................................... 87 6.5 COMPRESSION MEMBERS BACK TO BACK ...................................................... 90 6.6 RESTRAINTS ........................................................................................................... 91

SECTION 7 MEMBERS SUBJECT TO AXIAL TENSION 7.1 DESIGN FOR AXIAL TENSION ............................................................................. 93 7.2 NOMINAL SECTION CAPACITY ........................................................................... 93 7.3 DISTRIBUTION OF FORCES .................................................................................. 93 7.4 TENSION MEMBERS WITH TWO OR MORE MAIN COMPONENTS ................ 94 7.5 MEMBERS WITH PIN CONNECTIONS ................................................................. 96

SECTION 8 MEMBERS SUBJECT TO COMBINED ACTIONS 8.1 GENERAL ................................................................................................................. 97 8.2 DESIGN ACTIONS ................................................................................................... 97 8.3 SECTION CAPACITY .............................................................................................. 98 8.4 MEMBER CAPACITY .............................................................................................. 99

SECTION 9 CONNECTIONS 9.1 GENERAL ............................................................................................................... 107 9.2 DEFINITIONS ......................................................................................................... 111 9.3 DESIGN OF BOLTS ............................................................................................... 112 9.4 ASSESSMENT OF THE STRENGTH OF A BOLT GROUP ................................. 115 9.5 DESIGN OF A PIN CONNECTION ....................................................................... 116 9.6 DESIGN DETAILS FOR BOLTS AND PINS ......................................................... 117 9.7 DESIGN OF WELDS .............................................................................................. 118 9.8 ASSESSMENT OF THE STRENGTH OF A WELD GROUP ................................ 130 9.9 PACKING IN CONSTRUCTION ........................................................................... 131

SECTION 10 BRITTLE FRACTURE 10.1 METHODS .............................................................................................................. 132 10.2 NOTCH-DUCTILE RANGE METHOD .................................................................. 132 10.3 DESIGN SERVICE TEMPERATURE .................................................................... 132 10.4 MATERIAL SELECTION ....................................................................................... 133 10.5 FRACTURE ASSESSMENT ................................................................................... 137

SECTION 11 FATIGUE 11.1 GENERAL ............................................................................................................... 138 11.2 FATIGUE LOADING ............................................................................................. 141 11.3 DESIGN SPECTRUM ............................................................................................. 141 11.4 EXEMPTION FROM ASSESSMENT ..................................................................... 142 11.5 DETAIL CATEGORY ............................................................................................. 142 A

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AS 4100—1998 6

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11.6 FATIGUE STRENGTH ........................................................................................... 154 11.7 EXEMPTION FROM FURTHER ASSESSMENT .................................................. 155 11.8 FATIGUE ASSESSMENT ...................................................................................... 156 11.9 PUNCHING LIMITATION ..................................................................................... 156

SECTION 12 FIRE 12.1 REQUIREMENTS ................................................................................................... 157 12.2 DEFINITIONS ......................................................................................................... 157 12.3 DETERMINATION OF PERIOD OF STRUCTURAL ADEQUACY ..................... 158 12.4 VARIATION OF MECHANICAL PROPERTIES OF STEEL WITH

TEMPERATURE .................................................................................................... 158 12.5 DETERMINATION OF LIMITING STEEL TEMPERATURE .............................. 159 12.6 DETERMINATION OF TIME AT WHICH LIMITING TEMPERATURE IS

ATTAINED FOR PROTECTED MEMBERS ......................................................... 159 12.7 DETERMINATION OF TIME AT WHICH LIMITING TEMPERATURE IS

ATTAINED FOR UNPROTECTED MEMBERS .................................................... 161 12.8 DETERMINATION OF PSA FROM A SINGLE TEST .......................................... 162 12.9 THREE-SIDED FIRE EXPOSURE CONDITION ................................................... 162 12.10 SPECIAL CONSIDERATIONS .............................................................................. 163

SECTION 13 EARTHQUAKE 13.1 GENERAL ............................................................................................................... 165 13.2 DEFINITIONS ......................................................................................................... 165 13.3 DESIGN AND DETAILING REQUIREMENTS .................................................... 165

SECTION 14 FABRICATION 14.1 GENERAL ............................................................................................................... 168 14.2 MATERIAL ............................................................................................................. 168 14.3 FABRICATION PROCEDURES ............................................................................ 168 14.4 TOLERANCES........................................................................................................ 172

SECTION 15 ERECTION 15.1 GENERAL ............................................................................................................... 177 15.2 ERECTION PROCEDURES ................................................................................... 177 15.3 TOLERANCES........................................................................................................ 181 15.4 INSPECTION OF BOLTED CONNECTIONS ........................................................ 185 15.5 GROUTING AT SUPPORTS .................................................................................. 185

SECTION 16 MODIFICATION OF EXISTING STRUCTURES 16.1 GENERAL ............................................................................................................... 186 16.2 MATERIALS........................................................................................................... 186 16.3 CLEANING ............................................................................................................. 186 16.4 SPECIAL PROVISIONS ......................................................................................... 186

SECTION 17 TESTING OF STRUCTURES OR ELEMENTS 17.1 GENERAL ............................................................................................................... 187 17.2 DEFINITIONS ......................................................................................................... 187 17.3 TEST REQUIREMENTS......................................................................................... 187 17.4 PROOF TESTING ................................................................................................... 187 17.5 PROTOTYPE TESTING ......................................................................................... 188 17.6 REPORT OF TESTS ............................................................................................... 189

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7 AS 4100—1998

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APPENDICES A REFERENCED DOCUMENTS ............................................................................... 190 B SUGGESTED DEFLECTION LIMITS ................................................................... 193 C CORROSION PROTECTION ................................................................................. 195 D ADVANCED STRUCTURAL ANALYSIS ............................................................ 197 E SECOND ORDER ELASTIC ANALYSIS .............................................................. 198 F MOMENT AMPLIFICATION FOR A SWAY MEMBER ...................................... 199 G BRACED MEMBER BUCKLING IN FRAMES ..................................................... 200 H ELASTIC RESISTANCE TO LATERAL BUCKLING .......................................... 202 I STRENGTH OF STIFFENED WEB PANELS UNDER COMBINED ACTIONS .. 208 J STANDARD TEST FOR EVALUATION OF SLIP FACTOR ............................... 210 K INSPECTION OF BOLT TENSION USING A TORQUE WRENCH .................... 215

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AS 4100—1998 8

© Standards Australia www.standards.org.au

STANDARDS AUSTRALIA

Australian Standard

Steel structures

S E C T I O N 1 S C O P E A N D G E N E R A L

1.1 SCOPE AND APPLICATION

1.1.1 Scope

This Standard sets out minimum requirements for the design, fabrication, erection, and modification of steelwork in structures in accordance with the limit states design method.

This Standard applies to buildings, structures and cranes constructed of steel.

‘Text deleted’

This Standard does not apply to the following structures and materials:

(a) Steel elements less than 3 mm thick, with the exception of sections complying with AS/NZS 1163 and packers.

(b) Steel members for which the value of the yield stress used in design (fy) exceeds 690 MPa.

(c) Cold-formed members, other than those complying with AS/NZS 1163, which shall be designed in accordance with AS/NZS 4600.

(d) Composite steel-concrete members, which shall be designed in accordance with AS 2327.

(e) Road, railway and pedestrian bridges, which shall be designed in accordance with AS 5100.1, AS 5100.2 and AS 5100.6.

NOTE: The general principles of design, fabrication, erection, and modification embodied in this

Standard may be applied to steel-framed structures or members not specifically mentioned herein.

1.1.2 ‘Text deleted’

1.2 REFERENCED DOCUMENTS

The documents referred to in this Standard are listed in Appendix A.

1.3 DEFINITIONS

For the purpose of this Standard, the definitions below apply. Definitions peculiar to a particular Clause or Section are also given in that Clause or Section.

Action—the cause of stress or deformations in a structure.

Action effect or load effect—the internal force or bending moment due to actions or loads.

Authority—a body having statutory powers to control the design and erection of a structure.

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9 AS 4100—1998

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Bearing-type connection—Connection effected using either snug-tight bolts, or high- strength bolts tightened to induce a specified minimum bolt tension, in which the design action is transferred by shear in the bolts and bearing on the connected parts at the strength limit state.

Bearing-wall system—see AS 1170.4.

Braced frame—see AS 1170.4.

Braced frame, concentric—see AS 1170.4.

Braced frame, eccentric—see AS 1170.4.

Braced member—one for which the transverse displacement of one end of the member relative to the other is effectively prevented.

‘Text deleted’

Capacity factor—a factor used to multiply the nominal capacity to obtain the design capacity.

Complete penetration butt weld—a butt weld in which fusion exists between the weld and parent metal throughout the complete depth of the joint.

‘Text deleted’

Constant stress range fatigue limit—highest constant stress range for each detail category at which fatigue cracks are not expected to propagate (see Figure 11.6.1).

Cut-off limit—for each detail category, the highest variable stress range which does not require consideration when carrying out cumulative damage calculations (see Figures 11.6.1 and 11.6.2).

Design action effect or design load effect—the action or load effect computed from the design actions or design loads.

‘Text deleted’

Design action or design load—the combination of the nominal actions or loads and the load factors specified in AS/NZS 1170.0, AS/NZS 1170.1, AS/NZS 1170.2, AS/NZS 1170.3, AS 1170.4 or other standards referenced in Clause 3.2.1.

Design capacity—the product of the nominal capacity and the capacity factor.

Design life—period over which a structure or structural element is required to perform its function without repair.

Design resistance effect—the resistance effect computed from the loads and design capacities contributing towards the stability limit state resistance.

Design spectrum—sum of the stress spectra from all of the nominal loading events expected during the design life.

Detail category—designation given to a particular detail to indicate which of the S-N curves is to be used in the fatigue assessment.

Discontinuity—an absence of material, causing a stress concentration.

‘Text deleted’

‘Text deleted’

Ductility (of structure)—see AS 1170.4.

‘Text deleted’

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AS 4100—1998 10

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‘Text deleted’

‘Text deleted’

Exposed surface area to mass ratio—the ratio of the surface area exposed to the fire to the mass of steel.

Fatigue—damage caused by repeated fluctuations of stress leading to gradual cracking of a structural element.

Fatigue loading—set of nominal loading events described by the distribution of the loads, their magnitudes and the numbers of applications of each nominal loading event.

Fatigue strength—the stress range defined in Clause 11.6 for each detail category (see Figures 11.6.1 and 11.6.2) varying with the number of stress cycles.