AS/NZS 4600:2005 Australian/New Zealand Standard Cold-formed steel structures AS/NZS 4600:2005 AS/NZS 4600:2005 ThisJointAustralian/NewZealandStandardwaspreparedbyJointTechnical Committee BD-082, Cold-formed Steel Structures. It was approved on behalf of the Council of Standards Australia on 28 September 2005 and on behalf of the Council of Standards New Zealand on 23 September 2005.This Standard was published on 30 December 2005. The following are represented on Committee BD-082: Association of Consulting Engineers Australia Australian Building Codes Board Australian Chamber of Commerce and Industry Australian Steel Institute Bureau of Steel Manufacturers of Australia Engineers Australia NZ Structural Engineering Society NZ Heavy Engineering Research Association NZ Metal Roofing and Cladding Manufacturers Association Inc. Queensland University of Technology University of Sydney Welding Technology Institute of Australia Keeping Standards up-to-date Standardsarelivingdocumentswhichreflectprogressinscience,technologyand systems.Tomaintaintheircurrency,allStandardsareperiodicallyreviewed,and neweditionsarepublished.Betweeneditions,amendmentsmaybeissued. Standardsmayalsobewithdrawn.Itisimportantthatreadersassurethemselves theyareusingacurrentStandard,whichshouldincludeanyamendmentswhich may have been published since the Standard was purchased. Detailed information about joint Australian/New Zealand Standards can be found by visitingtheStandardsWebShopatwww.standards.com.auorStandardsNew Zealandwebsiteatwww.standards.co.nzandlookinguptherelevantStandardin the on-line catalogue. Alternatively,bothorganizationspublishanannualprintedCataloguewithfull detailsofallcurrentStandards.Formorefrequentlistingsornotificationof revisions,amendmentsandwithdrawals,StandardsAustraliaandStandardsNew Zealandofferanumberofupdateoptions.Forinformationabouttheseservices, users should contact their respective national Standards organization. WealsowelcomesuggestionsforimprovementinourStandards,andespecially encouragereaderstonotifyusimmediatelyofanyapparentinaccuraciesor ambiguities.PleaseaddressyourcommentstotheChiefExecutiveofeither StandardsAustraliaorStandardsNewZealandattheaddressshownontheback cover. This Standard was issued in draft form for comment as DR 03518. AS/NZS 4600:2005 Australian/New Zealand Standard Cold-formed steel structures First published in Australia as AS 15381974. Second edition 1988. AS 15381988 jointly revised and redesignated AS/NZS 4600:1996. Second edition 2005. COPYRIGHT Standards Australia/Standards New Zealand All rights are reserved. No part of this work may be reproduced or copied in any form or byanymeans,electronicormechanical,includingphotocopying,withoutthewrittenpermission of the publisher. Jointly published by Standards Australia, GPO Box 476, Sydney, NSW 2001 and StandardsNew Zealand, Private Bag 2439, Wellington 6020 ISBN 0 7337 7073 8 AS/NZS 4600:20052 PREFACE ThisStandardwaspreparedbytheJointStandardsAustralia/StandardsNewZealand Committee BD-082, Cold-formed Steel Structures, to supersede AS/NZS 4600:1996. TheobjectiveofthisStandardistoprovidedesignersofcold-formedsteelstructureswith specificationsforcold-formedsteelstructuralmembersusedforload-carryingpurposesin buildings and other structures. This edition incorporates the following major changes to the previous edition: (a)Alignment of terminology with AS/NZS 1170 series for structural design actions. (b)TheacceptanceofweldingofG450steeltoAS 1397usingexistingruleswitha minorchangeincapacityfactors.Thiscircumventstheconfusionforweldingof G450 steel. (c)IncreaseinthedesignstressofG550steeltoAS 1397,lessthan0.9 mmthickand greaterthanorequalto0.6 mmthick,from75%to90%,and75%forthicknessless than 0.6 mm of the specified values of yield stress and tensile strength. (d)The addition of web with holes to allow for holes in webs in shear and bearing. (e)Anewsetofdesignrulesforunstiffenedelementsandedgestiffenersunderstress gradient. (f)Minormodificationstotherulesforuniformlycompressedelementswithedgeand intermediatestiffenerstoremoveadiscontinuityintheequationswhichformerly existed. (g)A new approach for edge-stiffened elements with intermediate stiffeners. (h)A new approach for multiple intermediate stiffeners in compression flanges where the stiffeners no longer need to be fully effective. (i)The significant liberalization of the lateral buckling rules for beams to allow the AISI designcurvetobeusedwitharationalbucklinganalysis.Thiswillsignificantly increase the capacity of purlins throughout Australia and New Zealand. (j)The introduction of a whole new set of equations for web crippling (bearing) of webs withoutholesandremovalofunconservatisminthepreviouseditionwhichwas discovered by Australian research. (k)Bearing of nested Z-section. (l)The removal of l/1000 for angle sections in compression which are fully effective. (m)Additional design rules for fillet welds, flare welds and resistance welds. (n)Modification of the bearing coefficient for bolts to be a function of d/t for high values ofd/tandaseparatebearingcapacitygivenforboltswhereboltholedeformationis considered. (o)Significantreductionintheedgedistanceprovisionfrom3.0dto1.5dforscrew fasteners and blind rivets. (p)The addition of a new section on fatigue of cold-formed members. (q)Inclusionofnewdirectstrengthmethodasanalternativetotheeffectivewidth method of design. (r)Alignment of testing provisions with AS/NZS 1170.0. 3AS/NZS 4600:2005 ThisStandardwillbereferencedintheBuildingCodeofAustralia2006,thereby supersedingAS 46001996,whichwillbewithdrawn12 monthsfromthedateof publication of this Standard. Notestothetextcontaininformationandguidance.Theyarenotanintegralpartofthe Standard. A statement expressed in mandatory terms in a note to a table is deemed to be a requirement of this Standard. ThetermsnormativeandinformativehavebeenusedinthisStandardtodefinethe 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. AS/NZS 4600:20054 CONTENTS Page SECTION 1SCOPE AND GENERAL 1.1SCOPE ........................................................................................................................ 6 1.2NORMATIVE REFERENCES.................................................................................... 6 1.3DEFINITIONS ............................................................................................................ 6 1.4NOTATION .............................................................................................................. 13 1.5MATERIALS ............................................................................................................ 24 1.6DESIGN REQUIREMENTS ..................................................................................... 28 SECTION 2ELEMENTS 2.1SECTION PROPERTIES .......................................................................................... 34 2.2EFFECTIVE WIDTHS OF STIFFENED ELEMENTS ............................................. 36 2.3EFFECTIVE WIDTHS OF UNSTIFFENED ELEMENTS........................................ 41 2.4EFFECTIVE WIDTHS OF UNIFORMLY COMPRESSED ELEMENTS WITH AN EDGE STIFFENER................................................................................. 44 2.5EFFECTIVE WIDTHS OF UNIFORMLY COMPRESSED STIFFENED ELEMENTS WITH ONE INTERMEDIATE STIFFENER....................................... 47 2.6EFFECTIVE WIDTHS OF UNIFORMLY COMPRESSED STIFFENED ELEMENTS WITH MULTIPLE INTERMEDIATE STIFFENER............................ 48 2.7EFFECTIVE WIDTHS OF UNIFORMLY COMPRESSED EDGE-STIFFENED ELEMENTS WITH INTERMEDIATE STIFFENERS.............................................. 51 2.8ARCHED COMPRESSION ELEMENTS ................................................................. 52 SECTION 3MEMBERS 3.1GENERAL ................................................................................................................ 53 3.2MEMBERS SUBJECT TO AXIAL TENSION ......................................................... 53 3.3MEMBERS SUBJECT TO BENDING...................................................................... 54 3.4CONCENTRICALLY LOADED COMPRESSION MEMBERS .............................. 74 3.5COMBINED AXIAL COMPRESSION OR TENSION, AND BENDING................ 77 3.6CYLINDRICAL TUBULAR MEMBERS................................................................. 79 SECTION 4STRUCTURAL ASSEMBLIES 4.1BUILT-UP SECTIONS ............................................................................................. 81 4.2MIXED SYSTEMS ................................................................................................... 82 4.3LATERAL RESTRAINTS ........................................................................................ 82 4.4WALL STUDS AND WALL STUD ASSEMBLIES................................................. 87 SECTION 5CONNECTIONS 5.1GENERAL ................................................................................................................ 88 5.2WELDED CONNECTIONS...................................................................................... 88 5.3BOLTED CONNECTIONS....................................................................................... 99 5.4SCREWED CONNECTIONS.................................................................................. 104 5.5BLIND RIVETED CONNECTIONS....................................................................... 107 5.6RUPTURE............................................................................................................... 109 5.7OTHER CONNECTIONS USING ANY TYPE OF FASTENERS.......................... 110 5AS/NZS 4600:2005 Page SECTION 6FATIGUE 6.1GENERAL .............................................................................................................. 111 6.2CALCULATION OF MAXIMUM STRESSES AND STRESS RANGE................ 114 6.3DETAIL CATEGORIES FOR CLASSIFIED DETAILS......................................... 114 6.4FATIGUE ASSESSMENT...................................................................................... 117 SECTION 7DIRECT STRENGTH METHOD 7.1GENERAL .............................................................................................................. 119 7.2MEMBERS.............................................................................................................. 120 SECTION 8TESTING 8.1TESTING FOR DETERMINING MATERIAL PROPERTIES............................... 125 8.2TESTING FOR ASSESSMENT OR VERIFICATION............................................ 126 APPENDICES ANORMATIVE REFERENCES................................................................................ 128 BFLEXURAL MEMBERS SUBJECTED TO POSITIVE AND NEGATIVE BENDING................................................................................. 130 CPROTECTION ........................................................................................................ 131 DDISTORTIONAL BUCKLING STRESSES OF GENERAL CHANNELS, LIPPED CHANNELS AND Z-SECTIONS IN COMPRESSION AND BENDING .................................................................... 133 ESECTION PROPERTIES ........................................................................................ 137 FSTANDARD TESTS FOR SINGLE-POINT FASTENER CONNECTIONS.......... 141 GBIBLIOGRAPHY.................................................................................................... 146 AS/NZS 4600:20056 COPYRIGHT STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand Standard Cold-formed steel structures S E C T I O N 1 S C O P E A N D G E N E R A L1.1 SCOPE ThisStandardsetsoutminimumrequirementsforthedesignofstructuralmemberscold-formedtoshapefromcarbonorlow-alloysteelsheet,strip,plateorbarnotmorethan 25 mminthicknessandusedforload-carryingpurposesinbuildings.Itisalsoapplicable forstructuresotherthanbuildingsprovidedappropriateallowancesaremadefordynamic effects. This Standard does not apply to the design of structures subject to fire and brittle fracture. 1.2 NORMATIVE REFERENCES DocumentsreferredtointhisStandardarelistedinAppendix Aandareindispensablefor the application of this document. 1.3 DEFINITIONS ForthepurposeofthisStandard,thedefinitionsbelowapply.Definitionspeculiartoa particular clause or section are also given in that clause or section. 1.3.1 Action Set of concentrated or distributed forces acting on a structure (direct action), or deformation imposed on a structure or constrained within it (indirect action). 1.3.2 Action effect (internal effects of actions, load effects) Internal forces and bending moments due to actions (stress resultants). 1.3.3 Arched compression element Acircularorparabolicarch-shapedcompressionelementhavinganinsideradius-to-thickness ratio greater than 8, stiffened at both ends by edge stiffeners. (See Figure 1.3(d).) 1.3.4 Assemblage of elements A system of interconnected cold-formed steel elements that act together to resist earthquake actioninsuchawaythatthestrengthanddeformationcapacityofthesystemisnot adversely affected by the buckling or crippling of any one element of the assemblage. 1.3.5 Bend Portionadjacenttoflatelementsandhavingamaximuminsideradius-to-thicknessratio (ri/t) of 8. (See Figure 1.1.) 1.3.6 Braced member Memberforwhichthetransversedisplacementofoneendofthememberrelativetothe other is effectively prevented. 7AS/NZS 4600:2005 COPYRIGHT 1.3.7 Can Implies a capability or possibility and refers to the ability of the user of the Standard, or to a possibility that is available or that might occur. 1.3.8 Capacity design principles Appropriatematerialstandarddesignanddetailingprovisionswhichenablezoneswhere post-elasticresponseisacceptabletobeidentifiedanddetailedinamannerthatensures these zones are capable of accepting the inelastic demands placed upon them. NOTE: Allotherzonesaretobedesignedtoensurethatallotherundesirableinelasticresponse mechanismsaresuppressedanddetailedinamannerthattheultimatelimitstatehorizontal deformations that they are expected to be subjected to, can be sustained without significant (e.g., greater than 20%) loss of load-carrying capacity after four complete cycles of loading. 1.3.9 Capacity reduction factor A factor used to multiply the nominal capacity to obtain the design capacity. 1.3.10 Clinching Structuralfasteningoftwoormoreflatelementsbysingle-pointembossingorpiercing without using additional material. 1.3.11 Cold-formed steel structural members Shapesthataremanufacturedbypress-brakingblanksshearedfromsheets,cutlengthsof coilsorplates,orbyrollformingcold-orhot-rolledcoilsorsheets;bothforming operations being performed at ambient room temperature, that is, without manifest addition of heat as required for hot-forming. 1.3.12 Direct strength method Analternativedesignmethodthatprovidespredictionsofmemberresistancewithoutthe use of effective widths. 1.3.13 Design action effect The action effect computed from the design values of the actions or design loads. 1.3.14 Design capacity The product of the capacity reduction factor and the nominal capacity. 1.3.15 Distortional buckling A mode of buckling involving change in cross-sectional shape, excluding local buckling. 1.3.16 Doubly-symmetric section A section symmetric about two orthogonal axes through its centroid. (See Figure 1.5(a).) 1.3.17 Effective design width Where the flat width of an element is reduced for design purposes, the reduced design width is termed the effective width or effective design width. 1.3.18 Elements Simpleshapesintowhichacold-formedstructuralmemberisconsidereddividedandmay consist of the following shapes: (a)Flat elements Appearing in cross-section as rectangles. (See Figure 1.2.) (b)Bends Appearingincross-sectionassectorsofcircularrings,havingtheinside radius-to-thickness ratio less than or equal to eight (ri/t 8). (See Figure 1.2.) (c)Archedelements Circularorparabolicelementshavingtheinsideradius-to- thickness ratio greater than eight (ri/t > 8). (See Figure 1.2.) AS/NZS 4600:20058 COPYRIGHT 1.3.19 Feed width (wf) Width of coiled or flat steel used in the production of a cold-formed product. 1.3.20 Flexural-torsional buckling Amodeofbucklinginwhichcompressionmemberscanbendandtwistsimultaneously without change of cross-sectional shape. 1.3.21 Length (of a compression member) Theactuallength(l)ofanaxiallyloadedcompressionmember,takenasthelengthcentre-to-centre of intersections with supporting members, or the cantilevered length in the case of a freestanding member. 1.3.22 Limit states States beyond which the structure no longer satisfies the design criteria. NOTE: Limit states separate desired states (compliance) from undesired states (non-compliance). 1.3.23 Limit states, serviceability Statesthatcorrespondtoconditionsbeyondwhichspecifiedservicecriteriaforastructure or structural element are no longer met. 1.3.24 Limit states, stability Statesthatcorrespondtothelossofstaticequilibriumofastructureconsideredasarigid body. 1.3.25 Limit states, ultimate States associated with collapse, or with other similar forms of structural failure. NOTE: Thisgenerallycorrespondstothemaximumload-carryingresistanceofastructureor structural element, but, in some cases, to the maximum applicable strain or deformation. 1.3.26 Load The value of a force appropriate for an action. 1.3.27 Local buckling A mode of buckling involving plate flexure alone without transverse deformation of the line or lines of intersection of adjoining plates. 1.3.28 May Indicates the existence of an option. 1.3.29 Multiple-stiffened element Anelementthatisstiffenedbetweenwebs,orbetweenawebandastiffenededge,by meansofintermediatestiffenersthatareparalleltothedirectionofstress.(See Figure 1.3(c).) 1.3.30 Nominal action effect or nominal load Anunfactoredactioneffectorloaddeterminedinaccordancewiththerelevantloading Standard. 1.3.31 Nominal capacity Thecapacityofamemberorconnection,calculatedusingtheparametersspecifiedinthis Standard. 1.3.32 Nominal dimension A specified manufactured dimension. 9AS/NZS 4600:2005 COPYRIGHT 1.3.33 Point-symmetric section Asectionsymmetricalaboutapoint(centroid)suchasaZ-sectionhavingequalflanges. (See Figure 1.5(b).) 1.3.34 Primary structure Thestructuralsystemprovidedtocarrytheearthquakeforcesgeneratedinthestructureto the ground. 1.3.35 Proof testing Applicationoftestloadstoastructure,sub-structure,memberorconnection,toascertain the structural characteristics of only that one item under test. 1.3.36 Prototype testing Application of test loads to one or more structures, sub-structures, members or connections, to ascertain the structural characteristics of that class of structures, sub-structures, members or connections which are nominally identical to the units tested. 1.3.37 Pull-over (pull-through) Failureof asingle-pointconnectionby the sheetbeingpulledovertheheadof thefastener or the head of the fastener being pulled through the sheet. 1.3.38 Pull-out Failureofasingle-pointconnectionbytheembeddedpartofthefastenerbeingpulledout of the member. 1.3.39 Segment (in a member subjected to bending) Thelengthbetweenadjacentcross-sections,whicharefullyorpartiallyrestrained,orthe lengthbetweenanunrestrainedendandtheadjacentcross-section,whichisfullyor partially restrained. 1.3.40 Shall Indicates that a statement is mandatory. 1.3.41 Should Indicates a recommendation (non-mandatory). 1.3.42 Single-point fastener A mechanical connection at a single discrete point such as a screw or rivet. 1.3.43 Singly-symmetric (monosymmetric) section A section symmetric about only one axis through its centroid. (See Figure 1.5(c).) 1.3.44 Special study Aprocedurefortheanalysisordesign,orboth,ofthestructure,agreedbetweenthe authorityhavingstatutorypowerstocontrolthedesignanderectionofastructure,andthe design engineer. 1.3.45 Stiffened or partially stiffened compression element Aflatcompressionelement(i.e.,aplanecompressionflangeofaflexuralmemberora plane web or flange of a compression member) of which both edges parallel to the direction ofstressarestiffenedbyaweb,flange,edgestiffener,intermediatestiffener,orthelike. (See Figure 1.3(a).) AS/NZS 4600:200510 COPYRIGHT 1.3.46 Stiffeners 1.3.46.1 Edge stiffener Formed element at the edge of a flat compression element. (See Figure 1.4(a).) 1.3.46.2 Intermediate stiffeners Formedelements,employedinmultiple-stiffenedsegments,andlocatedbetweenedgesof stiffened elements. (See Figure 1.4(b).) 1.3.47 Structural ductility factor Anumericalassessmentoftheabilityofastructuretosustaincyclicinelastic displacements. 1.3.48 Structural performance factor A numerical assessment of the ability of a building to survive cyclic displacements. 1.3.49 Structural response factor The level of force reduction available for a given system compared with an elastic structural system. 1.3.50 Sub-element Theportionbetweenadjacentstiffeners,orbetweenwebandintermediatestiffener,or between edge and stiffener. 1.3.51 Tensile strength The minimum ultimate strength in tension specified for the grade of steel in the appropriate Standard. 1.3.52 Thickness The base steel thickness (t), exclusive of coatings. 1.3.53 Unformed steel Steel as received from the steel producer or warehouse before being cold-worked as a result of fabricating operations. 1.3.54 Unformed steel properties Mechanical properties of unformed steel, such as yield stress, tensile strength and ductility. 1.3.55 Unstiffened compression element Aflatcompressionelementwhichisstiffenedatonlyoneedgeparalleltothedirectionof stress. (See Figure 1.3(b).) 1.3.56 Yield stress Theminimumyieldstressintensionspecifiedforthegradeofsteelintheappropriate Standard. FIGURE1.1 BENDS 11AS/NZS 4600:2005 COPYRIGHT NOTE:The member illustrated consists of the following nine elements: (a)Elements 1, 3, 7, 9 are flat elements (flats). (b)Elements 2, 4, 6, 8 are bends (ri/t 8). (c)Element 5 is an arched element (ri/t > 8). FIGURE1.2 ELEMENTS FIGURE1.3 STIFFENING MODES AS/NZS 4600:200512 COPYRIGHT FIGURE1.4 STIFFENERS FIGURE1.5 EXAMPLES OF SECTION SYMMETRY 13AS/NZS 4600:2005 COPYRIGHT 1.4 NOTATION The symbols used in this Standard are listed in Table 1.4. Wherenon-dimensionalratiosareinvolved,boththenumeratoranddenominatorare expressed in identical units. The dimensional units for length and stress in all expressions or equations are to be taken as millimetres (mm) and megapascals (MPa) respectively, unless specifically noted otherwise. Anasteriskplacedafterasymboldenotesadesignactioneffectduetothedesignloadfor the ultimate limit state. TABLE 1.4 NOTATION SymbolDescriptionClause reference Acminor diameter area of a bolt5.3.5.1 Aeeffective area of the bearing stiffener subjected to uniform compressive stress; or effective area at the yield stress (fy) to calculate Ns; or effective area at the critical stress (fn) to calculate Nc 3.3.8.2, 3.4.1, 3.6.3 Aggross area of the element including stiffeners; or gross area of the cross-section 2.6.1, 3.2.2 Agtgross area subject to tension in block shear rupture5.6.3 Agvgross area subject to shear in block shear rupture5.6.3 Annet area of the cross-section; or net area of the connected part 3.2.2, 5.3.3, 5.4.2.2, 5.5.2.2 Antnet area subject to tension in block shear rupture5.6.3 Anvnet area subject to shear in block shear rupture5.6.3 Aoreduced area due to local buckling; or plain shank area of a bolt 3.6.3, 5.3.5.1 Asreduced area of a stiffener; or gross area of the stiffener; or cross-sectional area of a transverse stiffener; or tensile stress area of a bolt 2.5.2, 2.6.2.1, 3.3.8.1, 5.3.5.2 Aseeffective area of a stiffener2.4.2, 2.5.2 Astgross area of a shear stiffener3.3.8.3 As1, As2area of a member in compression consisting of the transverse stiffeners and a portion of the web 3.3.8.1 Awnnet area of the web5.6.1 abracing interval; or shear panel length for unstiffened web elements; or distance between transverse stiffeners for stiffened web elements; or distance between centre-lines of braces 3.3.3.2.1, 3.3.4.1, 3.3.8.3, 4.3.3.4 Bcconstant1.5.1.2 bflat width of element excluding radii; or length of the web hole; or flat width of element excluding corners or bends; or half the length of the arched compression element 2.2.1.2, 2.2.4.1, 2.5.2, 3.3.5, 4.1.2 (continued)AS/NZS 4600:200514 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference beeffective width of uniformly compressed stiffened and unstiffened elements used for determining the capacity 2.2.1.2, 2.2.2.2, 2.2.3.2, 2.3.1.2, 2.3.1.3, 2.3.2.2, 2.3.2.3, 2.4.2, 2.4.3, 2.5.3, 2.6.1, 2.6.2.2, 2.7 bedeffective width of uniformly compressed stiffened and unstiffened elements used for determining the deflection 2.2.1.3, 2.2.2.3 be1, be2effective width of stiffened element with stress gradient2.2.3.2, 2.2.3.3 bfflange width of a channel- or Z-section3.4.7, 4.3.3.3 bototal flat width of the stiffened element2.6.1, 2.6.2.1 bpgreatest sub-element flat width2.6.3.1 b1width of the flange projecting beyond the web for I-beams and similar sections; or half the distance between webs for box- or U-type sections; or sum of the flange projection beyond the web and the depth of the lip for I-beams and similar sections; or width of stiffened element 2.1.3.2, 2.1.3.3, 2.3.2.2 b2width of unstiffened element; or flat width of element with intermediate stiffener excluding radii; or total flat width of the edge-stiffened element 2.3.2.2, 2.5.2, 2.7 Cfor compression members, ratio of the total bend cross-sectional area to the total cross-sectional area of the full section; and for flexural members, ratio of the total bend cross-sectional area of the controlling flange to the full cross-sectional area of the controlling flange; or coefficient; or bearing factor 1.5.1.2, 3.3.6.2, 5.3.4.2, 5.4.2.3 Cbcoefficient depending on moment distribution in the laterally unbraced segment 3.3.3.2.1 Cihorizontal distance from the edge of the element to the centre-line of the stiffener 2.6.3.1 CTFcoefficient for unequal end moment3.3.3.2.1, 3.5.1 Clcoefficient of bearing length3.3.6.2 Cmscoefficient used to determine *ibNfor multiple-span system with midspan restraints 4.3.3.3 Cmx, Cmycoefficient for unequal end moment3.5.1 Crcoefficient of inside bent radius3.3.6.2 Cscoefficient for moment causing compression or tension on the shear centre side of the centroid 3.3.3.2.1 Cthcoefficient used to determine *ibNfor multiple-span system with third-point restraints 4.3.3.3 Ctrcoefficient used to determine *ibNfor multiple-span system with restraints at the support 4.3.3.3 Cwcoefficient of web slenderness3.3.6.2 Cycompression strain factor3.3.2.3 cfamount of curling2.1.3.2 (continued)15AS/NZS 4600:2005 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference ddepth of a section; or actual stiffener dimension 2.1.3.2, Figure 2.4.2(a), 3.3.6.3, 3.4.7 daaverage diameter of an arc spot weld at mid-thickness of tc; or average width of an arc seam weld 5.2.4.2, 5.2.5.2 deeffective diameter of a fused area of an arc spot weld; or effective width of an arc seam weld at fused surfaces 5.2.4.1, 5.2.4.2, 5.2.5.2 dfnominal diameter of a bolt, screw, blind rivetTable 5.3.1, 5.3.2, 5.3.4.2, 5.4.1, 5.4.2.1, 5.4.2.2, 5.4.2.3, 5.5.1, 5.5.2.1, 5.5.2.2, 5.5.2.3 dhdiameter of a hole2.2.2.2, Table 5.3.1, 5.3.2, 5.6.1 dlactual stiffener dimension; or overall depth of lip Figure 2.4.2(a) dooutside diameter of a tubular member3.6.1, 3.6.2 dsreduced effective width of a stiffener; or effective stiffener dimension Figure 2.4.2(b) dseeffective width of a stiffener; or effective stiffener dimension Figure 2.4.2(b) dshnominal shank diameterFigure F1, Appendix F dwdepth of the compressed portion of the web; or visible diameter of the outer surface of an arc spot weld; orwidth of an arc seam weld; or screw head or washer diameter 3.3.2.3, 5.2.4.2, 5.2.5.2, 5.4.3.2 dwccoped depth of a web5.6.1 dwhdepth of the web hole2.2.4.1, 3.3.4.2 d1depth of the flat portion of a web measured along the plane of the web; or width of elements adjoining the stiffened element 2.1.3.4, 2.2.4.1, 2.6.1, 3.3.4.1, 3.3.4.2, 3.3.6.2 EYoungs modulus of elasticity (200 103 MPa)2.2.1.2, 3.3.2.3, 5.2.4.2 eedge distance measured in the line of the force from centre-line of an arc spot weld, arc seam weld or from centre of a bolt hole to the nearest edge of an adjacent weld or bolt hole, or to the end of the connected part toward which the force is directed; or distance measured in the line of force from the centre of a standard hole to the nearest end of the connected part 5.2.4.3, 5.2.5.3, 5.3.2, 5.4.2.4, 5.5.2.4 eyyield strain3.3.2.3 *pF vertical design load supported by all purlin lines being restrained 4.3.3.3 fcstress at service load in the cover plate or sheet; or fatigue strength corrected for thickness of material 4.1.2, 6.1.3 fcrplate elastic buckling stress2.2.1.2, 3.4.2 ffuncorrected fatigue strength6.1.3 fncritical stress3.3.8.1, 3.4.1, 3.6.3 focelastic flexural, torsional and flexural-torsional buckling stress 3.4.1, 3.4.2, 3.4.3, 3.6.3 (continued)AS/NZS 4600:200516 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference fodelastic distortional buckling stress of the cross-section3.3.3.3, Paragraphs D1, D2, D3, Appendix D foxelastic buckling stress in an axially loaded compression member for flexural buckling about the x-axis 3.3.3.2.1 foyelastic buckling stress in an axially loaded compression member for flexural buckling about the y-axis 3.3.3.2.1 fozelastic buckling stress in an axially loaded compression member for torsional buckling 3.3.3.2.1, 3.4.3 frndetail category reference fatigue strength at nr-normal stress 6.1.3 frnccorrected detail category reference fatigue strength for normal stress 6.1.3 frsdetail category reference fatigue strength at nr-shear stress6.1.3 frsccorrected detail category reference fatigue strength for shear stress 6.1.3 futensile strength used in design; or tensile strength of sheet 1.5.1.1, 1.5.1.4, 1.5.1.6, 1.5.2, 3.2.2, 5.3.4.2 fufminimum tensile strength of a bolt5.3.5.1 fuvtensile strength of unformed steel1.5.1.2 fuwnominal tensile strength of a weld metal5.2.2.2, 5.2.3.4 fu1tensile strength used in the design of the connected plate of the thickness t1; or tensile strength of the sheet in contact with the screw head or with the rivet head 5.2.3.3, 5.4.2.3, 5.5.2.3 fu2tensile strength used in the design of the connected plate of the thickness t2; or tensile strength of the sheet not in contact with the screw head or with the rivet head 5.2.3.3, 5.4.2.3, 5.5.2.3 fyyield stress used in design; or yield stress of web steel; or yield stress of stiffener; or yield stress used in design for the lower strength base steel; or tensile or compressive yield stress 1.5.1.1, 1.5.1.4, 1.5.1.6, 1.5.2, 3.2.2, 3.3.2.3, 3.3.8.2, 5.2.2.1, 6.1.3, 8.1.3 fwylower yield stress value of the beam web (fy) or of the stiffener section (fys) 3.3.8.1 fyaaverage design yield stress of a full section1.5.1.2 fyctensile yield stress of bends1.5.1.2 fyfyield stress of flat portions; or yield stress of unformed steel if tests are not made; or yield stress of flat coupons of formed members 1.5.1.2, 8.1.4.1 fysyield stress of stiffener steel3.3.8.1 fyvtensile yield stress of unformed steel1.5.1.2 f3detail category fatigue strength at constant amplitude fatigue limit (5 106 cycles) 6.1.3 f3ccorrected detail category fatigue strength at constant amplitude fatigue limit 6.1.3 (continued)17AS/NZS 4600:2005 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference f5detail category fatigue strength at cut off limit (108 cycles) 6.1.3 f5ccorrected detail category fatigue strength at cut off limit6.1.3 f*design stress in the compression element calculated on the basis of the effective design width; or design stress range 2.2.1.2, 2.4.2, 6.1.3 *avf average design stress in the full, unreduced flange width2.1.3.2 *df design compressive stress in the element being considered, based on the effective section at the load for which deflections are determined 2.2.1.3, 2.2.2.3, 2.6.2.2, 2.6.3.2 *d1f calculated stress *1f 2.2.3.3 *d2f calculated stress *2f 2.2.3.3 *if design stress range for loading event i6.1.3 *2*1, f f web stresses calculated on the basis of the effective section specified in Clause 2.2.3.2 or the full section specified in Appendix F 2.2.3.2, 2.3.2.2 Gshear modulus of elasticity (80 103 MPa)3.3.3.2.1 Iaadequate second moment of area of a stiffener, so that each component element behaves as a stiffened element 2.4.2, 2.5.2 Ibsecond moment of area of the full, unreduced cross-section about the bending axis 3.5.1 Ieffeffective second moment of area for deflection7.1.4 Iggross second moment of area7.1.4 Imi n.minimum second moment of area2.8 Issecond moment of area of a full stiffener about its own centroidal axis parallel to the element to be stiffened 2.4.2, 2.5.2 Ispsecond moment of area of a stiffener about the centre-line of the flat portion of the element 2.6.2.1 Iwwarping constant for a cross-section3.3.3.2.1, Paragraph E1, Appendix E Ix, Iysecond moment of area of the cross-section about the principal x- and y-axes 3.3.3.2.1, 4.3.3.4 xI second moment of area of the cross-section about its centroidal axis perpendicular to the web 4.3.3.4 y x I product of second moment of area of the full section about its major and minor principal axes parallel and perpendicular to the web 4.3.3.4 Iycsecond moment of area of the compression portion of a section about the centroidal axis of the full section parallel to the web, using the full unreduced section 3.3.3.2.1 iindex for stiffener i2.6.3.1 Jtorsion constant for a cross-section3.3.3.2.1, Paragraph E1, Appendix E kplate buckling coefficient; or non-dimensional yield stress 2.2.1.2, 2.3.2.2, Table 2.4.2, 2.5.2, 2.6.1 kdplate buckling coefficient for distortional buckling2.6.1 kftotal population variation due to fabrication8.2.2 (continued)AS/NZS 4600:200518 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference klocplate buckling coefficient for local sub-element buckling2.6.1 kmtotal population of variation due to material8.2.2 ksshear stiffener coefficient3.3.8.3 kststiffener type coefficient3.3.8.2 ktcorrection factor for distribution of forces; or factor to allow for variability of structural units 3.2.2, Tables 3.2 and 8.2.3 kvshear buckling coefficient3.3.4.1, 3.3.8.3 k coefficient used to determine *ibNwhere neither flange is connected to the sheeting or connected to the sheeting with concealed fasteners 4.3.3.4 lactual length of a compression member; or full span for simple beams; or distance between inflection points for continuous beams; or twice the length of cantilever beams; or unbraced length of a member; or laterally unbraced length of a member; or length of a member 1.3.21, 2.1.3.3, 3.3.3.2.1, 3.3.3.2.2, 4.1.1, 4.3.3.3, 6.1.3 lalap lengthFigure F1, Appendix F lbactual length of bearing3.3.6.2, 3.3.6.3, 4.3.3.4 lbrunsupported length of bracing or other restraint that restricts distortional buckling of the element 2.6.2.1 lcunclamped length of the specimenFigure F1, Appendix F leeffective length of the member3.4.2 lex, ley, lezeffective buckling for bending about the x- and y-axes, and for twisting, respectively 3.3.3.2.1 lebeffective length in the plane of bending3.5.1 lggauge length for measuring the joint displacementFigure F1, Appendix F lstlength of transverse stiffener3.3.8.1 lsblength of bearing stiffener3.3.8.1 lulimit of unbraced length by which lateral-torsional buckling is not considered 3.3.3.2.2 lwlength of the full size of the weld; or length of fillet weld 5.2.2.1, 5.2.3.3, 5.2.3.4, 5.2.5.2 lw1, lw2leg lengths of fillet weld5.2.3.4 Mmoment due to nominal loads on member to be considered7.1.4 Mbnominal member moment capacity2.2.1.2, 3.3.1, 3.3.3.1, 3.3.3.2.1, 3.3.3.2.2, 3.3.3.3, 3.3.3.4, 3.3.5, 3.6.2, 7.2.2.1 Paragraph B2, Appendix B Mbx, Mbynominal member moment capacities about the x- and y-axes, respectively 3.5.1, 3.5.2 Mccritical moment3.3.3.2.1, 3.3.3.3 Mbdnominal member capacity for distortional buckling7.2.2.1, 7.2.2.4 Mbenominal member capacity for lateral-torsional buckling7.2.2.1, 7.2.2.2 (continued)19AS/NZS 4600:2005 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference Mblnominal member capacity for local buckling7.2.2.1, 7.2.2.3 Mmax.absolute value of the maximum moment in the unbraced segment 3.3.3.2.1 Mnnominal flexural capacity7.1.4 Moelastic buckling moment; or elastic lateral-torsional buckling moment 3.3.3.2.1, 7.2.2.2 Modelastic buckling moment in the distortional mode3.3.3.3, 7.2.2.4 Molelastic local buckling moment7.2.2.3 Msnominal section moment capacity2.2.1.2, 3.3.1, 3.3.2.1, 3.3.2.2, 3.3.2.3, 3.3.3.5, 3.3.5, 3.3.7 Msxf, Msyfnominal section yield moment capacity of the full section about the x- and y-axes, respectively 3.5.2 Mymoment causing initial yield at the extreme compression fibre of a full section 2.2.1.2, 3.3.3.2.1, 3.3.3.3 M1smaller bending moment at the ends of the unbraced length3.3.3.2 M2larger bending moment at the ends of the unbraced length3.3.3.2 M3absolute value of the moment at quarter point of the unbraced segment 3.3.3.2.1 M4absolute value of the moment at mid-point of the unbraced segment 3.3.3.2.1 M5absolute value of the moment at three-quarter point of the unbraced segment 3.3.3.2.1 M*design bending moment3.3.1, 3.3.5, 3.3.7, 3.6.2, Paragraph B2, Appendix B *y*x , M M design bending moment about the x- and y-axes, respectively 3.5.1, 3.5.2 mconstant; or non-dimensional thickness; or distance from the shear centre of one channel to the mid-plane of its web; or distance from the concentrated load to the brace 1.5.1.2, 4.1.1, 4.3.3.4, Paragraph E1, Appendix E Ncnominal member capacity of a member in compression2.2.1.3, 3.3.8.1, 3.4.1, 3.4.7, 3.5.1, 7.2.1.1 Ncdnominal member capacity for distortional buckling7.2.1.1, 7.2.1.4 Ncenominal member capacity for flexural, torsional or flexural-torsional buckling 7.2.1.1, 7.2.1.2 Nclnominal member capacity for local buckling7.2.1.1, 7.2.1.3 Neelastic buckling load3.5.1 Nfnominal tensile capacity of the section of the connected part 5.3.3 Nftnominal tensile capacity of a bolt5.3.5.2 Nocleast of the elastic column buckling load in flexural, torsional and flexural-torsional buckling 7.2.1.2 Nodelastic distortional compression member buckling load7.2.1.4 Nolelastic local buckling load7.2.1.3 (continued)AS/NZS 4600:200520 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference Nounominal pull-out capacity of a screw5.4.3.2 Novnominal pull-over (pull-through) capacity of a screw5.4.3.2 Nsnominal section capacity of a member in compression2.2.1.2, 3.3.8.1, 3.4.1, 3.5.1 Nslnominal axial capacity for local buckling7.2.1.1 Ntnominal section capacity of a member in tension; or nominal capacity of the connection in tension; or capacity of the net section of the connected part 3.2.1, 3.5.2, 5.4.2.2, 5.4.3.2, 5.5.2.2 Nwnominal tensile or compressive capacity of a butt weld or an arc spot weld 5.2.2.1, 5.2.4.4 Nynominal yield capacity of a member in compression7.2.1.2 N*design axial force, tensile or compressive; or design concentrated load or reaction 1.5.1.4, 3.2.1, 3.3.8.1, 3.4.1, 3.5.1, 3.5.2, 3.6.3, 4.1.1 *fN design tensile force on the net section of the connected part 5.3.3 *ftN design tensile force on a bolt5.3.5.2, 5.3.5.3 *ibN design force to be resisted by intermediate beam brace4.3.3.3, 4.3.3.4 *tN design tensile force on the net section of a connected part using screws or blind rivets 5.4.2.2, 5.4.3.2, 5.5.2.2 *wN design tensile or compressive force normal to the area of a butt weld or an arc spot weld 5.2.2.1, 5.2.4.4 nexponent2.5.2 ncnumber of compression flange stiffenersTable 7.1.2 nhnumber of holes in the critical plane5.6.1 ninumber of cycles of nominal loading event i, producing *if6.1.3 nnnumber of the shear planes with threads intercepting the shear plane 5.3.5.1 npnumber of parallel purlin lines4.3.3.3 nrreference number of stress cycles (2 106 cycles)6.1.3 nscnumber of stress cycles6.1.3 ntnumber of tension flange stiffenersTable 7.1.2 nwnumber of web stiffeners/foldsTable 7.1.2 nxnumber of shear planes without threads intercepting the shear plane 5.3.5.1 qintensity of the design load on a beam4.1.1 Rmodification factor for the distortional plate buckling coefficient; or reduction factor; or radius of outside bend surface 2.6.1, 3.3.3.4, 3.3.3.5, 3.6.3, 5.2.6.2 Rbnominal capacity for concentrated load or reaction for one solid web connecting top and bottom flanges 3.3.6.1, 3.3.6.2, 3.3.7 Rddesign capacity1.6.3, 8.2.3 Rfstructural response factor1.6.4.1 Rmi n.minimum value of the test results8.2.3 (continued)21AS/NZS 4600:2005 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference Rnnominal capacity for block shear rupture of the beam-end or tension member connection 5.6.3 Runominal capacity1.5.1.4, 1.6.3 Rwcweb crippling capacity for channel-section flexural member 3.3.8.2 R*design concentrated load or reaction in the presence of bending moment 3.3.6.1, 3.3.7 *bR design concentrated load or reaction4.1.1 rradius of gyration of the full, unreduced cross-section; or centre-line radius 3.4.2, Table 7.1.1 rcyradius of gyration of one channel about its centroidal axis parallel to the web 4.1.1 rfratio of the force transmitted by the bolts or screws, or rivets at the section considered, divided by the tensile force in the member at that section 5.4.2.2, 5.5.2.2 riinside bend radius1.5.1.2, 3.3.6.2 ro1polar radius of gyration of the cross-section about the shear centre 3.3.3.2.1, 3.4.3 rx, ryradii of gyration of the cross-section about the x- and y-axes, respectively 3.3.3.2 r1radius of gyration of I-section about the axis perpendicular to the direction in which buckling occurs for the given conditions of end support and intermediate bracing4.1.1 Sslenderness factor; or fastener distance from the centre-line of the web divided by the flange width for Z-section; or flange width minus the fastener distance from the centre-line of the web divided by the flange width for channel-sections; or spacing in line of the stress of welds, bolts, rivets connecting a cover plate, sheet or a non-integral stiffener in compression to another element 2.4.2, 2.5.2, 2.7, 3.4.7, 4.1.2 Seelastic section modulus of the effective section calculated with extreme compression or tension fibre at fy 3.3.3.5 Spstructural performance factor1.6.4.2.4 S*design action effects [design actions]5.6.3 sfastener distance from the centre-line of the web divided by the flange width for Z-sections 3.4.7, 4.1.2 sfspacing of bolts, screws or rivets perpendicular to the line of the force; or width of sheet, in the case of a single bolt, screw or rivet 5.3.3, 5.4.2.2, 5.5.2.2 sgvertical distance between two rows of connections nearest to the top and bottom flanges; or gauge, the distance measured at right angles to the direction of the design action in the member, centre-to-centre of holes in consecutive lines 4.1.1, 5.3.1 smax.maximum longitudinal spacing of welds or other connectors joining two channels to form an I-section 4.1.1 (continued)AS/NZS 4600:200522 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference spstaggered pitch distance measured parallel to the direction of the design action in the member, centre-to-centre of holes in consecutive lines 5.3.1 swweld spacing4.1.1 tnominal base steel thickness of any element or section exclusive of coatings; or thickness of the uniformly compressed stiffened elements; or base thickness of beam web; or thickness of a channel- or Z-section; or thickness of the cover plate or sheet; or thickness of the thinnest connected part; or thickness of element; or thickness of thinnest outside sheet; or thickness of the connected part; or thickness of the holed material; or base metal thickness; or thickness of the part in which the end distance is measured; or thickness of coped web 1.3.52, 2.1.3.1, 2.2.1.2, 2.6.1, 3.3.8.1, 3.4.7, 4.1.2, 4.3.3.3, 5.2.4.3, 5.2.5.2, 5.2.7, 5.3.1, 5.3.2, 5.3.4.2, 5.4.2.4, 5.5.2.4, 5.6.1 tctotal combined base steel thickness (exclusive of coatings) of sheets involved in shear transfer 5.2.4.2 tfthickness of the flange2.1.3.2 tpplate thickness6.1.3 tsthickness of the stiffener3.3.8.1 ttdesign throat thickness of a butt weld5.2.2.1, 5.2.3.4, 5.2.6.2 twthickness of a web2.1.3.4, 3.3.4.1, 3.3.6.2, 3.3.7 t1thickness of the connecting plate of the tensile strength fu1; or thickness of the sheet in contact with the screw head or rivet head 5.2.3.3, 5.4.2.3, 5.5.2.3 t2thickness of the connecting plate of the tensile strength fu2; or thickness of the sheet not in contact with the screw head or rivet head 5.2.3.3, 5.4.2.3, 5.5.2.3 Vbnominal bearing capacity of the connected part5.3.4.2, 5.3.4.3, 5.4.2.3, 5.5.2.3 Vfnominal shear capacity of the connected part along two parallel lines in the direction of the applied force 5.3.2 Vfvnominal shear capacity of a bolt or screw5.3.5.1, 5.4.2.1, 5.5.2.1 Vnnominal shear capacity of an arc seam weld or of a beam-end connection 5.2.5.2, 5.6.1 Vsccoefficient of variation of structural characteristic8.2.2, Table 8.2.3 Vvnominal shear capacity of the web3.3.4.1, 3.3.4.2, 3.3.5 Vwnominal shear capacity of a butt, fillet, arc spot, flare or resistance weld; or nominal shear force transmitted by the weld 5.2.2.2, 5.2.3.1, 5.2.4.2, 5.2.4.3, 5.2.6.2, 5.2.7 V*design shear force3.3.2.3, 3.3.4.1, 3.3.5 (continued)23AS/NZS 4600:2005 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference *bV design bearing force on a screw or on a rivet; or design bearing force on the connected part 5.4.2.3, 5.5.2.3 *fV design shear force of the connected part5.3.2 *fvV design shear force on a bolt, screw or rivet5.3.5.1, 5.3.5.3, 5.4.2.4 *nV design shear force on an arc seam weld or a beam-end connection 5.2.5.2, 5.6.1 *wV design shear force on a butt, fillet, arc spot, flare or resistance weld 5.2.2.2, 5.2.3.1, 5.2.4.2, 5.2.4.3, 5.2.6.2, 5.2.7 wwidth of the specimenFigure F1, Appendix F wffeed width of the coiled or flat sheet1.3.19, Note 2 to Figure E1, Appendix E x, yprincipal axes of the cross-section3.3.3.2.1, 3.3.6.3 xo, yocoordinates of the shear centre of the cross-section3.3.3.2 Zceffective section modulus calculated at a stress fc in the extreme compression fibre 3.3.3.3 Zeeffective section modulus calculated with the extreme compression or tension fibre at fy 3.3.2.2, 3.3.3.2.1 Zffull unreduced section modulus for the extreme compression fibre 3.3.3.2.1, 3.3.3.3 Zftsection modulus of the full unreduced section for the extreme tension fibre about the appropriate axis 3.5.2 coefficient; or modification factor for type of bearing connection 4.3.3.3, 5.3.4.2 nx, nymoment amplification factors3.5.1 sinverse of the slope of the S-N curve6.1.3 coefficient2.6.2.1 x, ymonosymmetry section constant about the x- and y-axes, respectively 3.3.3.2.1, Paragraph E2, Appendix E tfthickness correction factor6.1.3 importance factor2.6.2.1 coefficient2.6.2.1 angle between the plane of the web and the plane of the bearing surface; or angle between the vertical and the plane of the web of the Z-section 3.3.6.2, 4.3.3.3 , 1, 2slenderness ratio2.2.1.2, 3.3.2.3, 3.3.7 bnon-dimensional slenderness used to determine Mc for members subject to lateral buckling 3.3.3.2.1 cnon-dimensional slenderness used to determine fn; or non-dimensional slenderness used to determine Nce; or non-dimensional slenderness used to determine Mcd 3.4.1, 3.6.3, 7.2.1.2 dnon-dimensional slenderness used to determine Mc for members subject to distortional buckling; or non-dimensional slenderness used to determine Ncd and Mbd3.3.3.3, 7.2.1.4, 7.2.2.4 lnon-dimensional slenderness used to determine Ncl; or non-dimensional slenderness used to determine Mbl 7.2.1.3, 7.2.2.3 (continued)AS/NZS 4600:200524 COPYRIGHT TABLE 4.1 (continued) SymbolDescriptionClause reference structural ductility factor1.6.4.2.2 Poissons ratio2.2.1.2 capacity reduction factor1.5.1.4, 5.2.2.1, 5.2.2.2, 5.2.3.1, 5.2.4.2, 5.2.4.3, 5.2.5.2, 5.2.6.2, 5.2.7, 5.3.2, 5.3.3, 5.3.5.1, 5.3.5.2, 5.4.2.2, 5.4.2.3, 5.5.2.2, 5.5.2.3, 5.5.2.4, 5.6.1, 5.6.3, 6.1.3 bcapacity reduction factor for bending3.3.1, 3.5.1 ccapacity reduction factor for compression3.3.8.1, 3.4.1, 3.5.1 tcapacity reduction factor for tension3.2.1 vcapacity reduction factor for shear3.3.4.1 wcapacity reduction factor for bearing3.3.6.1, 3.3.8.2 quantity for load capacity; or effective width factor 1.5.1.2, 2.2.1.2, 2.3.2.2, 2.6.1 icoefficient2.6.3.1 stress ratio *1*2 / f f2.2.3.2, 2.3.2.2, 3.3.8.3 1.5 MATERIALS 1.5.1 Structural steel 1.5.1.1 Applicable steels Structural members or steel used in manufacturing shall comply with (a)AS 1163,AS 1397(excludingGrade G550,lessthan0.9 mminthickness), AS/NZS 1594, AS/NZS 1595 and AS/NZS 3678, as appropriate; and (b)othersteels,thepropertiesandsuitabilityofwhichareinaccordancewith Clause 1.5.1.4.Theyieldstress(fy)andtensilestrength(fu)usedindesignshallbe determined in accordance with Section 8 and AS 1391. 1.5.1.2 Strength increase resulting from cold forming Strength increase resulting from cold forming shall be permitted by substituting the average designyieldstress(fya)ofthefullsectionforfy.Suchincreaseshallbelimitedto Clauses 3.3(excludingClause 3.3.3.2),3.4,3.5,3.6and 4.4.Thelimitationsandmethods for determining fya shall be as follows: (a)For axially loaded compression members and flexural members whose proportions are such that the quantity () for load capacity is unity, as determined in accordance with Clause 2.2foreachofthecomponentelementsofthesections,theaveragedesign yield stress (fya) shall be determined on the basis of one of the following: (i)Full section tensile tests (see Section 8). (ii)Stub column tests (see Section 8). (iii)The following calculation: fya = Cfyc + (1 C)fyf fuv. . . 1.5.1.2(1)25AS/NZS 4600:2005 COPYRIGHT where fya=averagedesignyieldstressofthesteelinthefullsectionofcompression members or full flange sections of flexural membersC=forcompressionmembers,ratioofthetotalbendcross-sectional areatothetotalcross-sectionalareaofthefullsection;andfor flexuralmembers,ratioofthetotalbendcross-sectionalareaof thecontrollingflangetothefullcross-sectionalareaofthe controlling flange fyc=tensile yield stress of bends = ( )miyv c/ t rf B . . . 1.5.1.2(2)Equation 1.5.1.2(2)isapplicableonlyiffuv/fyvisgreaterthanor equalto1.2,ri/tislessthanorequalto7andtheminimum included angle is less than or equal to 120. Bc=constant =79 . 1 819 . 0 69 . 32yvuvyvuvffff. . . 1.5.1.2(3)fyv=tensile yield stress of unformed steel ri=inside bend radius m=constant =068 . 0 192 . 0yvuvff. . . 1.5.1.2(4)fuv=tensile strength of unformed steel fyf=yield stress of the flat portions (see Clause 8.1.4); or yield stress of unformed steel if tests are not made (b)Foraxiallyloadedtensionmembers,fyashallbedeterminedbyeitherItem (a)(i)or Item (a)(iii). 1.5.1.3 Effect of welding The effect of any welding on the mechanical properties of a member shall be determined on thebasisoftestsonspecimensofthefullsectioncontainingtheweldwithinthegauge length.Anynecessaryallowanceforsucheffectshallbemadeinthestructuraluseofthe member.WeldedconnectionsforallgradesconformingwithAS 1163andgradesG250, G300,G350andG450steelconformingwithAS 1397,designedinaccordancewith Clause 5.2.3 for fillet welds and Clause 5.2.6 for flare welds do not require further testing. 1.5.1.4 Ductility Steels not listed in Clause 1.5.1.1 and used for forming structural members and connections shall comply with the following requirements: (a)Theratiooftensilestrengthtoyieldstressshallbenotlessthan1.08.Thetotal elongationshallbenot lessthan 10% fora50 mmgauge lengthor7% for a200 mm gaugelengthstandardspecimentestedinaccordancewithAS 1391.Ifthese requirements cannot be met, the following criteria shall be satisfied: AS/NZS 4600:200526 COPYRIGHT (i)Localelongationina13 mmgaugelengthacrossthefractureshallbenotless than 20%. (ii)Uniform elongation outside the fracture shall be not less than 3%. Iftheductilityofthematerialisdeterminedonthebasisofthelocaland uniformelongationcriteria,theuseofsuchmaterialshallberestrictedtothe designofpurlinsandgirtsinaccordancewithClauses 3.3.2.2,3.3.3.2,3.3.3.3 and 3.3.3.4.Forpurlinsandgirtssubjecttocombinedaxialloadandbending moment (see Clause 3.5), N*/Ru shall not exceed 0.15 where N*=design axial force =capacity reduction factor Ru=nominal capacity (b)SteelsconformingtoAS 1397,Grade 550,lessthan0.9 mminthickness,whichdo not comply with Item (a) may be used provided (i)theyieldstress(fy)usedindesigninSections 2,3and 4,andthetensile strength(fu)usedindesigninSection 5aretakenas90%ofthecorresponding specifiedvaluesor495 MPa,whicheveristhelesser,andforsteellessthan 0.6 mminthickness,theyieldstress(fy)usedindesigninSections 2,3and 4, and the tensile strength (fu)used in design inSection 5 are taken as 75%of the corresponding specified values or 410 MPa, whichever is the lesser; or (ii)the suitability of such steel can be demonstrated by load test in accordance with Section 8. 1.5.1.5 Acceptance of steels Certifiedmilltestreports,ortestcertificatesissuedbythemill,shallconstitutesufficient evidence of compliance with the Standards referred to in this Standard. Theuncoatedminimumsteelthicknessatanylocationofthecold-formedproduct,as deliveredtothejobsite,shallbenotlessthan95%ofthevalueusedinitsdesign. However,lesserthicknessesshallbepermittedatbends(formingcorners)duetocold-forming effects. 1.5.1.6 Unidentified steel Ifunidentifiedsteelisused,itshallbefreefromsurfaceimperfectionsandshallbeused onlywheretheparticularphysicalpropertiesofthesteelanditsweldabilitywillnot adversely affect the design capacities and serviceability of the structure. Unless a full test in accordancewithAS 1391ismade,theyieldstressofthesteelusedindesign(fy)shallbe 170 MPa or less, and the tensile strength used in design (fu) shall be 300 MPa or less. 1.5.2 Design stresses Theminimumyieldstress(fy)andtensilestrength(fu)usedindesignshallnotexceedthe values given in Table 1.5 for the appropriate steel grade. NOTE: Regardless of the closeness of yield stress and tensile strength of some steels, steel grades giveninTable 1.5aresuitableforcold-formingprovidedthatanappropriateinsidebendradius (ri) is chosen. 27AS/NZS 4600:2005 COPYRIGHT TABLE 1.5 MINIMUM STRENGTHS OF STEELS COMPLYING WITH AS 1163, AS 1397, AS/NZS 1594, AS/NZS 1595 AND AS/NZS 3678 Applicable Standard Grade Yield stress (fy) MPa Tensile strength (fu) MPa AS 1163C250 and C250L0 C350 and C350L0 C450 and C450L0 250 350 450 320 430 500 G250 G300 G350 250 300 350 320 340 420 AS 1397 G450* G500 G550 450 500 550 480 520 550 HA1 HA3 HA4N (see Note) 200 170 (see Note) 300 280 HA200 HA250, HU250 HA250/1 200 250 250 300 350 350 HA300, HU300 HA300/1, HU300/1 HW350 300 300 350 400 430 430 HW350 HA400 340 380 450 460 AS/NZS 1594 XF300 XF400 XF500 300 380 480 440 460 570 CA220 CA260 CW300 210 250 300 340 350 450 AS/NZS 1595 CA350 CA500 350 500 430 510 200 (t 8 mm) 200 (8 mm < t 12 mm) 200 200 300 300 250, 250L15 (t 8 mm) 250, 250L15 (8 mm < t 12 mm) 250, 250L15 (12 mm < t 20 mm) 250, 250L15 (20 mm < t 25 mm) 280 260 250 250 410 410 410 410 300, 300L15 (t 8 mm) 300, 300L15 (8 mm < t 12 mm) 300, 300L15 (12 mm < t 20 mm) 300, 300L15 (20 mm < t 25 mm) 320 310 300 280 430 430 430 430 350, 350L15 (t 8 mm) 350, 350L15 (8 mm < t 12 mm) 350, 350L15 (12 mm < t 20 mm) 350, 350L15 (20 mm < t 25 mm) 360 360 350 340 450 450 450 450 400, 400L15 (t 8 mm) 400, 400L15 (8 mm < t 12 mm) 400, 400L15 (12 mm < t 20 mm) 400, 400L15 (20 mm < t 25 mm) 400 400 380 360 480 480 480 480 AS/NZS 3678 450, 450L15 (t 8 mm) 450, 450L15 (8 mm < t 12 mm) 450, 450L15 (12 mm < t 20 mm) 450, 450L15 (20 mm < t 25 mm) 450 450 450 420 520 520 520 500 (continued)AS/NZS 4600:200528 COPYRIGHT TABLE 1.5 (continued) Applicable Standard Grade Yield stress (fy) MPa Tensile strength (fu) MPa WR350, WR350/L0 (t 8 mm) WR350, WR350/L0 (8 mm < t 12 mm) WR350, WR350/L0 (12 mm < t 20 mm) WR350, WR350/L0 (20 mm < t 25 mm) 340 340 340 340 450 450 450 450 *Applies to hard-rolled material of thickness greater than or equal to 1.5 mm Applies to hard-rolled material of thickness greater than 1.0 mm but less than 1.5 mm Applies to hard-rolled material of thickness less than or equal to 1.0 mm NOTE: Fordesignpurposes,yieldandtensilestrengthsapproximatethoseofstructuralGrade HA200.For specific information contact the supplier. 1.5.3 Fasteners and electrodes 1.5.3.1 Steel bolts, nuts and washers Steelbolts,nutsandwashersshallcomplywithAS 1110.1,AS 1111.1,AS 1112.1, AS 1112.2,AS 1112.3,AS 1112.4,AS/NZS 1252,AS/NZS 1559andAS 4291.1 (ISO 898-1), as appropriate. Theuseofhigh-strengthfasteners,otherthanthosecomplyingwithAS/NZS 1252,is permitted provided that evidence of their equivalence to high-strength bolts complying with AS/NZS 1252 is available. 1.5.3.2 Welding consumables AllweldingconsumablesshallcomplywithAS/NZS 1554.1,AS/NZS 1554.5and ANSI/AWS D1.3, as appropriate. 1.5.3.3 Screws Self-drilling screws shall comply with AS 3566.1 and AS 3566.2. 1.5.3.4 Blind rivets Blind rivets shall comply with the Industrial Fastener Institute document F114. 1.6 DESIGN REQUIREMENTS 1.6.1 Actions and combination of actions A structure and its components shall be designed for the actions and combination of actions as specified in AS/NZS 1170.0. 1.6.2 Structural analysis and design Structural analysis and design shall be in accordance with AS/NZS 1170.0. NOTE: Guidanceontheapplicabilityofelasticstructuralanalysistocontinuousbeamsand frames is given in Appendix B. 1.6.3 Design capacity The design capacity (Rd) shall be determined by any one of the following: (a)Thenominalcapacity(Ru)inaccordancewithSections 2to 5andthecapacity reduction factor () given in Table 1.6 as appropriate, i.e., Rd = Ru. (b)Testing in accordance with Clause 8.2.3. 29AS/NZS 4600:2005 COPYRIGHT (c)WherethecompositionorconfigurationofsuchcomponentsissuchthatItem (a) or (b)cannotbemadeinaccordancewiththoseprovisions,structuralperformance shallbeestablishedfromthedesigncapacityorstiffnessbyrationalengineering analysisbasedonappropriatetheory,relatedtestingifdataisavailableand engineering judgement. Specifically, the design capacity shall be determined from the calculated nominal capacity by applying the following capacity reduction factors: (i)For members ...................................................................................... = 0.80. (ii)For connections .................................................................................. = 0.65. 1.6.4 Earthquake design 1.6.4.1 For Australia Allstructuresshallbedesignedfortheactionsandcombinationofactionsspecifiedin AS 1170.4.Ifcold-formedsteelmembersareusedastheprimaryearthquakeresistance element,thenthestructuralresponsefactor(Rf)shallbelessthanorequalto2.0,unless specified otherwise. 1.6.4.2 For New Zealand 1.6.4.2.1 General All structures shall be designed for the actions specified in NZS 1170.5 and combination of actions specified in AS/NZS 1170.0, subject to the limitations specified in Clauses 1.6.4.2.2 to 1.6.4.2.4. 1.6.4.2.2 Structural ductility factor For the ultimate limit state, the structural ductility factor () shall be taken as follows: (a)Forseismic-resistingsystemsinvolvinganassemblageofelementsactingasasingle unit, shall be less than or equal to 1.25. (b)Forseismic-resistingsystemsusingsemi-rigidconnections,shallbelessthanor equal to 1.25. (c)Whereaspecialstudyisundertaken(seeClause 1.6.4.2.3),maybeincreasedbut shall not be greater than 4.0. (d)For all other earthquake-resisting systems, = 1.0. For the serviceability limit state, = 1.0. NOTES:1Anexample ofan assemblageof elementsis a braced wallpanel,wherethewholepanel and its attachments at the top and base contribute to the earthquake resistance. 2Earthquake resisting systems using semi-rigid connections cover frames with connections that are flexurally weaker than the members framing into the connection. 1.6.4.2.3 Special studies Where it is demonstrated by special study that for a particular structural system is greater than 1.25, then (a) shall be based specifically from studies including the (i)structural form and configuration under consideration; (ii)ductility of the material; (iii)location of yielding regions of the structure; (iv)structural damping characteristics involved in the structural system; and (v)needtoprovidethestructurewithasmallmarginagainstcollapseunderthe maximum considered event in accordance with NZS 1170.5. AS/NZS 4600:200530 COPYRIGHT (b)where greater than 1.25 is applicable to a design, then capacity design shall be used in order to protect elements of the earthquake resisting system from inelastic demands beyond their capability to dependably resist such demands; and (c)forbuildingscontainingoneormoresuspendedfloors,capacitydesignprinciples shall be used to suppress inelastic demand in individual column members. 1.6.4.2.4 Structural performance factor Whenconsideringlateralstabilityofawholestructure,thestructuralperformancefactor (Sp) shall be taken as 1.0. For the ultimate limit state, Sp shall be taken as follows: (a)Where is less than or equal to 2.0, but not less than 1.0 Sp = 1.3 0.3. . . 1.6.4.2.3(b)Where is greater than 2.0, then Sp = 0.70. For the serviceability limit state, Sp = 0.70. 1.6.5 Durability 1.6.5.1 General A structure shall be designed to perform its required functions during its expected life. Wheresteelworkinastructureistobeexposedtoacorrosiveenvironment,thesteelwork shallbegivenprotectionagainstcorrosion.Thedegreeofprotectionshallbedetermined afterconsiderationhasbeengiventotheuseofthestructure,itsmaintenanceandthe climatic or other local conditions. 1.6.5.2 Corrosion protection NOTE: CorrosionprotectionshouldcomplywithAS/NZS 2311andAS/NZS 2312,as appropriate. For further information, see Appendix C. 31AS/NZS 4600:2005 COPYRIGHT TABLE 1.6 CAPACITY REDUCTION FACTOR Design capacityClause reference Capacity reduction factor() (a)Stiffeners:3.3.8 Transverse stiffeners (c)3.3.8.10.85 Bearing stiffeners (w)3.3.8.20.90 Shear stiffeners (v)3.3.8.30.90 (b)Members subject to axial tension (t)3.2.10.90 (c)Members subject to bending:3.3 Section moment capacity3.3.2 for sections with stiffened or partially stiffened compression flanges (b) 3.3.20.95 for sections with unstiffened compression flanges (b)3.3.20.90 Member moment capacity members subject to lateral buckling (b)3.3.3.20.90 members subject to distortional buckling (b)3.3.3.30.90 beams having one flange through-fastened to sheeting (channels or Z-sections) (b) 3.3.3.40.90 Web design shear (v)3.3.40.90 Bearing (w) for built-up sectionsTable 3.3.6.2(A)0.750.90 for single web channel and channel-sectionsTable 3.3.6.2(B)0.750.90 for single web Z-sectionsTable 3.3.6.2(C)0.750.90 for single hat sectionsTable 3.3.6.2(D)0.750.90 for multiple web deck sectionsTable 3.3.6.2(E)0.600.90 (d)Concentrically loaded compression members (c)3.40.85 (e)Combined axial load and bending:3.5 Compression (c)3.5.10.85 Bending (b)3.5.1 using Clause 3.3.20.90 or 0.95 using Clause 3.3.3.10.90 (f)Cylindrical tubular members:3.6 Bending (b)3.6.20.95 Compression (c)3.6.30.85 (g)Welded connections:5.2 Butt welds5.2.2 tension or compression5.2.2.10.90 shear5.2.2.2(a)0.80 shear (base metal)5.2.2.2(b)0.90 (continued)AS/NZS 4600:200532 COPYRIGHT TABLE 1.6 (continued) Design capacityClause reference Capacity reduction factor() Fillet welds5.2.3 longitudinal loading5.2.3.20.55 or 0.60 transverse loading5.2.3.30.60 Arc spot welds (puddle welds)5.2.4 shear (welds)5.2.4.2(a)0.60 shear (connected part)5.2.4.2(b)0.50 or 0.60 shear (minimum edge distance)5.2.4.30.60 or 0.70 tension5.2.4.40.65 Arc seam welds5.2.5 shear (welds)5.2.5.20.60 shear (connected part)5.2.5.20.60 Flare welds5.2.6 transverse loading5.2.6.2(a)0.55 longitudinal loading5.2.6.2(b)0.55 Resistance welds5.2.7 spot welds5.2.7(a)0.65 (h)Bolted connections:5.3 Tearout5.3.20.60 or 0.70 Net section tension:5.3.3 With washers5.3.3(a) double shear connection0.65 single shear connection0.55 Without washers5.3.3(b)0.65 Bearing5.3.40.55 or 0.65 Bolts5.3.5 bolt in shear5.3.5.10.80 bolt in tension5.3.5.20.80 (i)Screwed connections:5.4 Screwed connections in shear5.4.2 tension in the connected part5.4.2.20.65 tilting and hole bearing5.4.2.30.5 tearout5.4.2.40.60 or 0.70 Screwed connections in tension5.4.3 pull-out of connected parts5.4.3.10.5 pull-over (pull-through) of connected parts5.4.3.10.5 (continued)33AS/NZS 4600:2005 COPYRIGHT TABLE 1.6 (continued) Design capacityClause reference Capacity reduction factor() (j)Blind riveted connections:5.5 Riveted connections in shear5.5.2 tension in the connected part5.5.2.20.65 tilting and hole bearing5.5.2.30.50 tearout5.5.2.40.60 or 0.70 (k)Rupture: Shear rupture5.6.10.75 Block shear rupture (bolted connections)5.6.30.65 AS/NZS 4600:200534 COPYRIGHT S E C T I O N 2 E L E M E N T S2.1 SECTION PROPERTIES 2.1.1 General Propertiesofsections,suchascross-sectionalarea,secondmomentofarea,section modulus,radiusofgyration,andcentroid,shallbedeterminedinaccordancewith conventionalmethodsbydivisionofthesectionshapeintosimpleelements,including bends. Propertiesshallbebasedonnominaldimensionsandnominalbasesteelthickness(see Clause 1.5.1.6). 2.1.2 Design procedures 2.1.2.1 Full section properties Properties of full, unreduced sections shall be based on the entire simplified shape with the flatsandbendslocatedalongtheelementmid-linesunlessthemanufacturingprocess warrants consideration of a more accurate method. Tocalculatethestabilityofmembers,asimplifiedshapewherethebendsareeliminated andthesectionisrepresentedbystraightmid-linesmaybeusedwhencalculatingthe following properties: (a)Parameters for distortional buckling (see Appendix D). (b)Location of shear centre (see Paragraph E1 of Appendix E). (c)Warping constant (see Paragraph E1 of Appendix E). (d)Monosymmetry section constant (see Paragraph E2 of Appendix E). 2.1.2.2 Effective section properties For the design of cold-formed members with slender elements, the area of the sections shall be reduced at specified locations. The reduction of the area is required to (a)compensate for the effects of shear lag (see Clause 2.1.3.3); and (b)compensate for local instabilities of elements in compression (see Clauses 2.2 to 2.5). 2.1.2.3 Location of reduced width The location of reduced width shall be determined as follows: (a)Forthedesignofuniformlycompressedstiffenedelements,thelocationofthelost portion shall be taken at the middle of the element (see Figures 2.2.1 and 2.4.2(b)). (b)For the design of stiffened elements under a stress gradient or where only a part of the element is in compression (e.g., the webs), the location of the lost portion shall be as shown in Figure 2.2.3. (c)Forunstiffenedelements,undereitherastressgradientoruniformcompression,the lostportionshallbetakenattheunstiffenededgeasshowninFigure 2.3.1.Ifthe unstiffened element is subjected to both tension and compression across its width, the lost portion may be taken as specified in Clause 2.3.2. (d)For the design of elements with an edge stiffener, the location of the lost portion shall be as shown in Figure 2.4.2. 35AS/NZS 4600:2005 COPYRIGHT 2.1.3 Dimensional limits 2.1.3.1 Maximum flat-width-to-thickness ratios Themaximumoverallflat-width-to-thicknessratios(b/t),disregardingintermediate stiffeners and taking t as the nominal thickness of the element, shall be as follows: (a)For a stiffened compression element having one longitudinal edge connected to a web or flange element and the other stiffened by (i)simple lip ..............................................................................................60; and (ii)any other kind of stiffener when (A)Is < Ia...........................................................................................60; and (B)Is Ia................................................................................................. 90. (b)For a stiffened compression element with both longitudinal edges connected to other stiffened elements ........................................................ 500. (c)For a unstiffened compression element .................................................................. 60. NOTE: Unstiffenedcompressionelementswithb/tratiosgreaterthan30andstiffened compressionelementswithb/tratiosgreaterthan250arelikelytodevelopnoticeable deformation at the full design load, without affecting the ability of the member to carry the design load.Stiffenedelementswithb/tratiosgreaterthan500canbeusedwithadequatedesign capacitytosustainthedesignloads.However,substantialdeformationsofsuchelementsusually will invalidate the design equations of this Standard. 2.1.3.2 Flange curling Wheretheflangeofaflexuralmemberisunusuallywideanditisdesiredtolimitthe maximumamountofcurlingormovementoftheflangetowardtheneutralaxis,the maximum width (b1) of the compression and tension flanges, either stiffened or unstiffened projectingbeyondthewebforI-beamsandsimilarsectionsorthemaximumhalfdistance (b1)betweenwebsforbox-orU-typebeams,shallbedeterminedfromthefollowing equation: 4f*avf1100 061 . 0dcfdE tb =. . . 2.1.3.2where tf=thickness of the flange d=depth of the section *avf =average design stress in the full, unreduced flange width (see Note 1) cf=amount of curling (see Note 2) NOTES:1Wheremembersaredesignedbytheeffectivedesignwidthprocedure,theaveragestress equalsthemaximumstressmultipliedbytheratiooftheeffectivedesignwidthtotheactual width. 2Theamountofcurlingthatcanbetoleratedwillvarywithdifferentkindsofsectionsand shouldbeestablishedbythedesigner.Amountofcurlingintheorderof5%ofthedepthof the section is usually not considered excessive. 2.1.3.3 Shear lag effects (usually short spans supporting concentrated loads) Where the span of the beam (l) is less than 30b1 and the beam carries one concentrated load, orseveralloadsspacedgreaterthan2b1,theeffectivedesignwidthofanyflange,whether in tension or compression, shall be limited to the values given in Table 2.1.3.3. AS/NZS 4600:200536 COPYRIGHT ForflangesofI-beamsandsimilarsectionsstiffenedbylipsattheouteredges,b1shallbe taken as the sum of the flange projection beyond the web and the depth of the lip. TABLE 2.1.3.3 MAXIMUM RATIO OF EFFECTIVE DESIGN WIDTH TO ACTUAL WIDTH FOR SHORT WIDE FLANGE BEAMS l/b1Ratiol/b1Ratio 301.00140.82 250.96120.78 200.91100.73 180.8980.67 160.8660.55 NOTE: l = full span for simple beams; or distancebetweeninflectionpointsforcontinuousbeams; or twice the length of cantilever beams 2.1.3.4 Maximum web depth-to-thickness ratio The maximum web depth-to-thickness ratio (d1/tw) of flexural members shall not exceed the following: (a)For unreinforced webs:d1/tw.............................................................................. 200. (b)For webs with transverse stiffeners complying with Clause 3.3.8.1 (i)if using bearing stiffeners only:d1/tw................................................... 260; and (ii)if using bearing stiffeners and intermediate stiffeners:d1/tw....................... 300; where d1=depth of the flat portion of the web measured along the plane of the web tw=thickness of web Whereawebconsistsoftwoormoresheets,theratiod1/twshallbecalculatedforeach sheet. 2.2 EFFECTIVE WIDTHS OF STIFFENED ELEMENTS 2.2.1 Uniformly compressed stiffened elements 2.2.1.1 General Foruniformlycompressedstiffenedelements(seeFigure 2.2.1),theeffectivewidthsfor sectionormembercapacityanddeflectioncalculationsshallbedeterminedinaccordance with Clauses 2.2.1.2 and 2.2.1.3 respectively. 2.2.1.2 Effective width for capacity calculations Fordeterminingthesectionormembercapacity,theeffectivewidths(be)ofuniformly compressedstiffenedelementsshallbedeterminedfromEquation 2.2.1.2(1)or Equation 2.2.1.2(2), as appropriate. For 0.673:be = b. . . 2.2.1.2(1)For > 0.673:be = b. . . 2.2.1.2(2)37AS/NZS 4600:2005 COPYRIGHT where b=flat width of element excluding radii (see in Figure 2.2.1(a)) =effective width factor = 0 . 122 . 01 . . . 2.2.1.2(3)The slenderness ratio () shall be determined as follows: =cr*ff. . . 2.2.1.2(4)where f *=designstressinthecompressionelementcalculatedonthebasisoftheeffective design width (see Figure 2.2.1(b)) fcr=plate elastic buckling stress = ( )2221 12 bt E k. . . 2.2.1.2(5)k=plate buckling coefficient =4 for stiffened elements supported by a web on each longitudinal edge (kvalues for different types of elements are given in the applicable clauses)E=Youngs modulus of elasticity (200 103 MPa) =Poissons ratio t=thickness of the uniformly compressed stiffened elements Alternatively,theplatebucklingcoefficient(k)foreachflatelementmaybedetermined fromarationalelasticbucklinganalysisofthewholesectionasaplateassemblage subjected to the longitudinal stress distribution in the section prior to buckling. FIGURE2.2.1 STIFFENED ELEMENTS WITH UNIFORM COMPRESSION Fordeterminingthenominalsectionormembercapacityofflexuralmembers,thedesign stress (f *) shall be taken as follows: (a)Ifthenominalsectionmomentcapacity(Ms)isbasedoninitiationofyieldingas specified in Clause 3.3.2.2, and the initial yielding of the element being considered is incompression,thenf *shallbeequaltofy.Iftheinitialyieldingofthesectionisin tension,thenf *oftheelementbeingconsideredshallbedeterminedonthebasisof the effective section at My (moment causing initial yield). AS/NZS 4600:200538 COPYRIGHT (b)Ifthe nominal sectionmoment capacity (Ms) is basedon inelastic reserve capacity as specified in Clause 3.3.2.3, then f * shall be the stress of the element being considered at Ms. The effective section shall be used to determine Ms. (c)If the nominal member moment capacity (Mb) is based on lateral buckling as specified inClause 3.3.3.2orondistortionalbucklingasspecifiedinClause 3.3.3.3,thenf * shall be equal to fc as described in Clauses 3.3.3.2 and 3.3.3.3 in determining Zc. Fordeterminingthenominalsectionormembercompressioncapacity,f *shallbetakenas follows: (i)Ifthenominalsectioncapacity(Ns)ofthememberincompressionisbasedon initiation of yielding as specified in Clause 3.4, then f * shall be equal to fy. (ii)Ifthenominalmembercapacity(Nc)ofthememberincompressionisbasedon flexural,torsionalorflexural-torsionalbucklingasspecifiedinClause 3.4,thenf * shall be equal to fn, as specified in Clauses 3.4.1 and 3.4.6. 2.2.1.3 Effective width for deflection calculations Fordeterminingthedeflection,theeffectivewidths(bed)shallbedeterminedfrom Equation 2.2.1.3(1) or Equation 2.2.1.3(2), as appropriate. For 0.673:bed = b. . . 2.2.1.3(1)For > 0.673:bed = b. . . 2.2.1.3(2)Theeffectivewidthfactor()shallbedeterminedbyeitherofthefollowingtwo procedures: (a)Procedure I Alowestimateoftheeffectivewidthmaybeobtainedfrom Equations 2.2.1.2(3)and 2.2.1.2(4),exceptthat *df issubstitutedforf *where *df is thedesigncompressivestressintheelementbeingconsideredbasedontheeffective section at the load for which deflections are determined. (b)Procedure II Forstiffenedelementssupportedbyaweboneachlongitudinaledge, animprovedestimateoftheeffectivewidthcanbeobtainedbycalculatingfrom Equations 2.2.1.3(3) to 2.2.1.3(5), as appropriate. For 0.673: = 1. . . 2.2.1.3(3)For 0.673 < 0.5band>3dh,theeffectivewidth(be)ofuniformly compressedstiffenedelementswithcircularholesshallbedeterminedfrom Equation 2.2.2.1(1) or Equation 2.2.2.2(2), as appropriate. For 0.673:be = b dh. . . 2.2.2.2(1)For > 0.673: hhe8 . 0 22 . 01d bbdbb = . . . 2.2.2.2(2)wheredhisthediameterofholesandshallbecalculatedinaccordancewith Clause 2.2.1.2. The value of be shall not exceed (b dh). 2.2.2.3 Effective width for deflection calculations Fordeterminingthedeflection,theeffectivewidth(bed)shallbeequaltobedeterminedin accordance with Procedure I of Clause 2.2.1.3 except that *dfis substituted for f * where *dfisthedesigncompressivestressoftheelementbeingconsidered,basedontheeffective section at the load for which deflections are determined. 2.2.3 Stiffened elements with stress gradient 2.2.3.1 General Forstiffenedelementswithstressgradient(seeFigure 2.2.3),theeffectivewidthsfor sectionormembercapacityanddeflectioncalculationsshallbedeterminedinaccordance with Clauses 2.2.3.2 and 2.2.3.3, respectively. 2.2.3.2 Effective width for capacity calculations For determining the section or member capacity, the effective width (be1) (see Figure 2.2.3) shall be determined from the following: =3ee1bb. . . 2.2.3.2(1)The effective width (be2) (see Figure 2.2.3) shall be determined from Equation 2.2.3.2(2) or Equation 2.2.3.2(3), as appropriate. For 0.236: 2ee2bb = . . . 2.2.3.2(2)where(be1 + be2)shallnotexceedthecompressionportionofthewebcalculatedonthe basis of effective section. For > 0.236:be2 = be be1. . . 2.2.3.2(3)where be= effectivewidthdeterminedinaccordancewithClause 2.2.1.2with *1fsubstituted for f * and with k determined as follows: k=4 + 2(1 )3 + 2(1 ). . . 2.2.3.2(4)= *1*2ff. . . 2.2.3.2(5)AS/NZS 4600:200540 COPYRIGHT *2*1/ f f =webstressescalculatedonthebasisoftheeffectivesection (see Figure 2.2.3) *1f iscompression(+)and *2f canbeeithertension()orcompression (+). In case *1fand *2fare both compression, *1f shall be greater than or equal to *2f . 2.2.3.3 Effective width for deflection calculations Fordeterminingthedeflection,theeffectivewidths(be1)and(be2)shallbedeterminedin accordance with Clause 2.2.3.2 except that *1 dfand *d2fare substituted for *1fand *2f . The calculatedstresses *1f and *2f (seeFigure 2.2.3)shallbeusedtodetermine *1 df and *d2f , respectively.Calculationsshallbebasedontheeffectivesectionfortheloadforwhich deflections are determined. FIGURE2.2.3 STIFFENED ELEMENTS AND WEBS WITH STRESS GRADIENT 41AS/NZS 4600:2005 COPYRIGHT 2.2.4 Channel-section webs with holes and with stress gradient 2.2.4.1 General Thecalculationofcapacityanddeflectionforchannel-sectionwebswithholesandwith stress gradient shall be applicable within the following limits: (a)dwh/d1 < 0.7. . . 2.2.4.1where dwh=depth of the web hole d1=depth of the flat portion of the web measured along the plane of the web(b)d1/t 200. (c)Holes centred at mid-depth of the web. (d)Clear distance between holes is greater than or equal to 450 mm. (e)Non-circular holes corner radii greater than or equal to 2t. (f)Non-circularholeswithdwh 65 mmandb 115 mm,wherebisthelengthofthe web hole. (g)Circular hole diameters less than or equal to 150 mm. (h)dwh > 15 mm. 2.2.4.2 Capacity calculations Whendwh/d1 < 0.38,theeffectivewidths(b1)and (b2)shallbedeterminedinaccordance with Clause 2.2.3 by assuming no hole exists in the web. When dwh/d1 0.38, the effective width shall be determined in accordance with Clause 2.3.1 assuming the compression portion of the web consists of an unstiffened element adjacent to the hole with f * = f1 as shown in Figure 2.3.2. 2.2.4.3 Deflection calculations TheeffectivewidthsshallbedeterminedinaccordancewithClause 2.2.3byassumingno hole exists in the web. 2.3 EFFECTIVE WIDTHS OF UNSTIFFENED ELEMENTS 2.3.1 Uniformly compressed unstiffened elements 2.3.1.1 General Foruniformlycompressedunstiffenedelements(seeFigure 2.3.1),theeffectivewidthsfor sectionormembercapacityanddeflectioncalculationsshallbedeterminedinaccordance with Clauses 2.3.1.2 and 2.3.1.3, respectively. 2.3.1.2 Effective width for capacity calculations Fordeterminingthesectionormembercapacity,theeffectivewidths(be)ofuniformly compressedunstiffenedelementsshallbedeterminedinaccordancewithClause 2.2.1.2 with the exception that k shall be taken as 0.43 and b shall be as shown in Figure 2.3.1. 2.3.1.3 Effective width for deflection calculations Fordeterminingthedeflection,theeffectivewidths(be)shallbedeterminedinaccordance with Procedure I of Clause 2.2.1.3 except that *dfis substituted for f * and k = 0.43. AS/NZS 4600:200542 COPYRIGHT FIGURE2.3.1 UNSTIFFENED ELEMENT WITH UNIFORM COMPRESSION 2.3.2 Unstiffened elements and edge stiffeners with stress gradient 2.3.2.1 General Forunstiffenedelementsandedgestiffenerswithstressgradient,theeffectivewidthsfor sectionormembercapacityanddeflectioncalculationsshallbedeterminedinaccordance with Clauses 2.3.2.2 and 2.3.2.3, respectively. 2.3.2.2 Effective width for capacity calculations Fordeterminingthesectionormembercapacity,theeffectivewidths(be)measuredfrom thesupportededgeofunstiffenedcompressionelementsandedgestiffenerswithstress gradient shall be determined in accordance with Clause 2.2.1.2 with *1*f f =and with k and determined in accordance with this Clause. *2*1, f f=stressesshowninFigures 2.3.2(A)and (B)calculatedonthebasisofthe grosssectionwhere *1f iscompression(+)and *2f canbeeithertension ()orcompression(+).Inthecasewhere *1f and *2f arebothin compression *2*1f f =stress ratio = *1*2 / f f . . . 2.3.2.2(1)Theeffectivewidthfactor()andtheplatebucklingcoefficient(k)shallbedeterminedas follows: (a)Forunstiffenedelementswithstressgradientcausingcompressionatboth longitudinaledgesoftheunstiffenedelement( )*2*1and f f bothincompression,as shown in Figure 2.3.2(A). shallbedeterminedusingEquation 2.2.1.2(3)andshallbedeterminedusing Equation 2.2.1.2(4).Thebucklingcoefficient(k)inEquation 2.2.1.2(5)shallbe determined as follows: (i)Where the stress decreases toward the unstiffened edge of the element as shown in Figure 2.3.2(A)(a), k shall be calculated as follows: 0.340.578+=k. . . 2.3.2.2(2)(ii)Where the stress increases toward the unstiffened edge of the element as shown in Figure 2.3.2(A)(b), k shall be calculated as follows: 20.07 0.21 0.57 + = k . . . 2.3.2.2(3)43AS/NZS 4600:2005 COPYRIGHT (b)For unstiffened elements with stress gradient causing compression at one longitudinal edge and tension at the other longitudinal edge of the unstiffened element: (i)For *1f incompressionattheunsupportededgeand *2f intensionasshownin Figure 2.3.2(B)(a), shall be calculated as follows: = 1for 0.673(1 ) ( )( ) =1 22 . 011 for > 0.673(1 ). . . 2.3.2.2(4) shall be determined using Equation 2.2.1.2(4) k = 0.57 0.21 + 0.072. . . 2.3.2.2(5)(ii)For *1f incompressionatthesupportededgeand *2f intensionasshownin Figure 2.3.2(B)(b), shall be calculated as follows: For 1 < 0: = 1for 0.673 ( ) + =0.2211 for > 0.673 . . . 2.3.2.2(6) shall be determined using Equation 2.2.1.2(4) k = 1.70 5 + 17.12. . . 2.3.2.2(7)For 1: = 1 Alternatively,theplatebucklingcoefficient(k)inEquation 2.3.2.2(5)maybedetermined usingEquation 2.3.2.2(8)forplainchannelsbentintheplaneofsymmetrywiththe unsupported edge of the unstiffened element in compression as follows: k = 0.1451(b2/b1) + 1.256. . . 2.3.2.2(8)where b2=width of the unstiffened element b1=width of the stiffened element Forothertypesofsections,kinEquations 2.3.2.2(2),2.3.2.2(3),2.3.2.2(5)and 2.3.2.2(7) fortheunstiffenedelementandkforeachremainingflatelementofthesectionmaybe determinedfromarationalelasticbucklinganalysisofthewholesectionasaplate assemblage subjected to the longitudinal stress distribution in the section prior to buckling. Incalculatingtheeffectivesectionmodulus(Ze)inClause 3.3.2.2orinClause 3.3.3.2,the extreme compression fibre in Figures 2.3.2(A)(b) and 2.3.2(B)(a) is taken as the edge of the effective section (closer to the unsupported edge). In calculating the effective section modulus (Ze) in Clause 3.3.2.2, the extreme tension fibre in Figure 2.3.2(B)(b) is taken as the edge of the effective section (closer to the unsupported edge). AS/NZS 4600:200544 COPYRIGHT (a)Inward facing lip(b)Outward facing lip FIGURE2.3.2(A) UNSTIFFENED ELEMENTS WITH STRESS GRADIENT BOTH EDGES IN COMPRESSION (a)Compression at the unsupported edge(b)Compression at the supported edge FIGURE2.3.2(B) UNSTIFFENED ELEMENTS WITH STRESS GRADIENT ONE EDGE IN COMPRESSION AND ONE EDGE IN TENSION 2.3.2.3 Effective width for deflection calculations Fordeterminingthedeflection,theeffectivewidths(be)ofunstiffenedelementsandedge stiffeners with stress gradient shall be determined in accordance with Clause 2.3.2.2. except that *1 df and *2 df aresubstitutedfor *1f and *2f .Thecalculatedstresses *1f and *2f (see Figures 2.3.2(A)and 2.3.2(B)shallbeusedtodetermine *1 df and *2 df respectively. Calculationsshallbebasedontheeffectivesectionfortheloadforwhichdeflectionsare determined. 2.4 EFFECTIVEWIDTHSOFUNIFORMLYCOMPRESSEDELEMENTSWITH AN EDGE STIFFENER 2.4.1 General Foruniformlycompressedelementswithanedgestiffener,theeffectivewidthsforsection ormembercapacityanddeflectioncalculationsshallbedeterminedinaccordancewith Clauses 2.4.2 and 2.4.3 respectively. 45AS/NZS 4600:2005 COPYRIGHT 2.4.2 Effective width for capacity calculations Fordeterminingthesectionormembercapacity,theeffectivewidths(be)ofuniformly compressed elements with an edge stiffener shall be determined as follows: (a)Stb0.328 Ia=(no edge stiffener is required) =adequatesecondmomentofareaofthestiffener,sothateachcomponentelement behaves as a stiffened element be=b. . . 2.4.2(1)b1=b2 = b/2(see Figure 2.4.2). . . 2.4.2(2)ds=dse(for simple lip stiffener). . . 2.4.2(3)As=Ase(for other stiffener shapes). . . 2.4.2(4)(b)Stb0.328 >=as e12 II bb(see Figure 2.4.2). . . 2.4.2(5)b2 = be b1(see Figure 2.4.2). . . 2.4.2(6)=asse sIId d(for simple lip stiffener). . . 2.4.2(7)(for other stiffener shapes). . . 2.4.2(8)set seasse s d AIIA A== (for stiffener shown in Figure 2.4.2). . . 2.4.2(9)12sin2 3s t dI = (for stiffener shown in Figure 2.4.2). . . 2.4.2(10)( ) ( )+ = 5 115 0.328 399434aSt btSt bt I . . . 2.4.2(11)IfIsisgreaterthanorequaltoIa,thenIsisequaltoIainEquation 2.4.2(5),(7),(8)and Table 2.4.2. ( )3140.582 =St bn. . . 2.4.2(12)*/ 28 . 1factor s slendernesf ES== . . . 2.4.2(13) *f= stress (see Figure 2.4.2(b)) beshallbecalculatedinaccordancewithClause 2.2.1.2,wherekshallbeasgivenin Table 2.4.2. AS/NZS 4600:200546 COPYRIGHT TABLE 2.4.2 DETERMINATION OF PLATE BUCKLING COEFFICIENT (k) Plate buckling coefficient (k) Simple lip edge stiffener (140 40) dl/b 0.250.25 dl/b 0.8 Other edge stiffener shapes 4 43 . 0 57 . 3nsa +II4 0.4354.82nas +IIbdl4 43 . 0 57 . 3nas +II FIGURE2.4.2 ELEMENTS WITH SIMPLE-LIP EDGE STIFFENER 2.4.3 Effective width for deflection calculations Fordeterminingthedeflection,theeffectivewidths(be)shallbedeterminedinaccordance with Clause 2.4.2, except that *dfis substituted for f *. 47AS/NZS 4600:2005 COPYRIGHT 2.5 EFFECTIVEWIDTHSOFUNIFORMLYCOMPRESSEDSTIFFENED ELEMENTS WITH ONE INTERMEDIATE STIFFENER 2.5.1 General Foruniformlycompressedelementswithanintermediatestiffener(seeFigure 2.5.2),the effectivewidthsforsectionormembercapacityanddeflectioncalculationsshallbe determined in accordance with Clauses 2.5.2 and 2.5.3 respectively. 2.5.2 Effective width for capacity calculations Fordeterminingthesectionormembercapacity,theeffectivewidths(be)ofuniformly compressed elements with one intermediate stiffener shall be determined as follows: (a)Stb2 Ia=0 (no intermediate stiffener is required) =adequatesecondmomentofareaofthestiffener,sothateachcomponent element behaves as a stiffened element be=b. . . 2.5.2(1)b=flat width of element excluding corners or bends (see Figure 2.5.2) As=reduced area of the stiffener =Ase. . . 2.5.2(2)Ase=effective area of the stiffener Asshallbeusedincalculatingtheoveralleffectivesectionproperties.Thecentroidofthe stiffener shall be considered located at thecentroidof the fullarea of the stiffener, and the second moment of area of the stiffener about its own centroidal axis shall be that of the full section of the stiffener. (b)Stb>2 =asse sIIA A. . . 2.5.2(3)n=exponent = ( )3112/583 . 02St b . . . 2.5.2(4)k=plate buckling coefficient =1 3nas+II. . . 2.5.2(5)( ) = 50/502 4aSt bt IforStbS 32< 0.673. . . 2.6.1(2) Eftbk*o1.052= . . . 2.6.1(3)bo=total flat width of the stiffened element (see Figure 2.6.1(B)) Ag=gross area of the element including stiffeners t=thickness of element Theplatebucklingcoefficient(k)shallbedeterminedfromtheminimumofRkdandkloc, determined in accordance with Clause 2.6.2 or Clause 2.6.3 as appropriate, where R=modification factor for the distortional plate buckling coefficient =2if bo/d1 < 1 = ( )215111 o d bif bo/d1 1. . . 2.6.1(4)kd=platebucklingcoefficientfordistortionalbucklingcalculatedusing Equation 2.6.2.1(2) kloc=platebucklingcoefficientforlocalsub-elementbucklingcalculatedusing Equation 2.6.2.1(1) d1=widthofelementsadjoiningthestiffenedelement,e.g.,thedepthof thewebinahatsectionwithmultipleintermediatestiffenersinthe compressionflangeisequaltod1;iftheadjoiningelementshave different widths, use the smallest one FIGURE2.6.1(A) EFFECTIVE WIDTH LOCATIONS FIGURE2.6.1(B) PLATE WIDTHS AND STIFFENER LOCATIONS AS/NZS 4600:200550 COPYRIGHT 2.6.2 Specific case: n identical stiffeners, equally spaced 2.6.2.1 Capacity calculation kloc = 4(n + 1)2. . . 2.6.2.1(1)( ) ( )( ) [ ] 1 11 1222d+ ++ + +=nnk . . . 2.6.2.1(2)( ) [ ]411 1 + + = n . . . 2.6.2.1(3)3osp92 . 10t bI= . . . 2.6.2.1(4)t bAos= . . . 2.6.2.1(5)where =coefficient =importance factor =coefficient Isp=second moment of area of a stiffener about the centre-line of the flat portion of the element. The radii which connect the stiffener to the flat may be included bo=total flat width of the stiffened element (see Figure 2.6.1(B)) As=gross area of the stiffener Iflbr < bathenlbr/boshallbepermittedtobesubstitutedfortoaccountforincreased capacity due to bracing, where lbr is the unsupported length of bracing or other restraint that restricts distortional buckling of the element. 2.6.2.2 Deflection calculation Theeffectivewidth(be)usedincalculatingdeflectionshallbedeterminedinaccordance withClause 2.6.2.1,exceptthat *df shallbesubstitutedforf *,where *df isthedesign compressivestressintheelementbeingconsideredbasedontheeffectivesectionatthe load for which deflections are determined. 2.6.3 General case: Arbitrary stiffener size, location and number 2.6.3.1 Capacity calculation 2poloc4=bbk . . . 2.6.3.1(1)( )++ +===n1 ii i2n1 ii i22d2 12 1 k. . . 2.6.3.1(2)41n1 ii i1 2+ == . . . 2.6.3.1(3)51AS/NZS 4600:2005 COPYRIGHT ( )3oispi92 . 10t bI= . . . 2.6.3.1(4)=oi 2isinbC . . . 2.6.3.1(5)( )t