was approved on behalf of the Council of the Standards Association of Australia on was approved on behalf of the Council of the Standards Association of Australia on 21 April 1988 and published on 15 July 1988.
21 April 1988 and published on 15 July 1988.
The following interests are represented on Committee TM/102: The following interests are represented on Committee TM/102:
Austra
Australian lian British Chamber of British Chamber of CommeCommercerce Austra
Australian lian FedeFederation of ration of Timber Timber MerchMerchants Associationsants Associations Australian Institute of Building
Australian Institute of Building Austra
Australian lian Timber Importers’ Timber Importers’ FedeFederationration
CSIRO, Division of Construction and Engineering CSIRO, Division of Construction and Engineering Department of Forestry, Qld
Department of Forestry, Qld Electrici
Electricity ty Supply AssociaSupply Association tion of of AustraAustralialia Forest
Forest ProducProducts ts AssAssociation, W.A.ociation, W.A. Forest
Forestry ry CommissCommission ion of of N.S.WN.S.W..
Master Builders Federation of Australia Master Builders Federation of Australia
National Association of Australian State Road Authorities National Association of Australian State Road Authorities New South Wales Timber Advisory Council
New South Wales Timber Advisory Council Public Works Department, New South Wales Public Works Department, New South Wales Radiata Pine
Radiata Pine ResResearcearch h Institute Inc.Institute Inc. Rail Track and Sleeper Association Rail Track and Sleeper Association Railwa
Railways of ys of AustraliAustralia a CommitteCommitteee Royal Australian Institute of Architects Royal Australian Institute of Architects Tasmanian Timber Promotion Board Tasmanian Timber Promotion Board The
The AssocAssociation of iation of ConsultinConsulting Engineers Australiag Engineers Australia Timber Merchants Association of South Australia Timber Merchants Association of South Australia Timber Merchants Association of
Timber Merchants Association of VictoriaVictoria Timber Preservers Associa
Timber Preservers Association tion of of AustraliAustraliaa Timber Promotion Council
Timber Promotion Council
Timber Research and Development Advisory Council Timber Research and Development Advisory Council Timber and
Timber and Building MateriaBuilding Material l MercMerchants hants AssocAssociation, N.S.Wiation, N.S.W Universit
Universities and ies and collegcollegeses Victorian S
Victorian S awmawmillers illers AssocAssociationiation Woods and Forests Department, S.A Woods and Forests Department, S.A Additional interes
Additional interests ts particparticipating in ipating in preparpreparation of ation of StandarStandard:d: Austra
Australian lian Timber ResearcTimber Research h institute Inc.institute Inc. Austra
Australian lian Uniform Building Uniform Building RegulaRegulations Co-ordinating Counciltions Co-ordinating Council
Rev
Rev iew iew of of AustrAustr aliaalia n n StandaStanda rds.rds. To keep abreast of To keep abreast of progress in industry, Australiprogress in industry, Australian Standards are subject an Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensure that they are in possession of the latest edition, and any important therefore that Standards users ensure that they are in possession of the latest edition, and any amendments thereto.
amendments thereto.
Full details of all Australian Standards and related publications will be found in the Standards Australia Full details of all Australian Standards and related publications will be found in the Standards Australia Catalogue of Publications; this information is supplemented each month by the magazine ‘The Australian Catalogue of Publications; this information is supplemented each month by the magazine ‘The Australian Standard’, which subscribing members receive, and which gives details of new publications, new editions Standard’, which subscribing members receive, and which gives details of new publications, new editions and amendments, and of withdrawn Standards.
and amendments, and of withdrawn Standards.
Suggestions for improvements to Australian Standards, addressed to the head office of
Suggestions for improvements to Australian Standards, addressed to the head office of Standards AusStandards Australia,tralia, are welcomed. Notification of any inaccuracy or ambiguity found in
are welcomed. Notification of any inaccuracy or ambiguity found in an Australian Australian Standard should be madean Standard should be made without delay in order that the matter may be investigated and appropriate action taken.
without delay in order that the matter may be investigated and appropriate action taken.
This Standard was issued in draft form for comment as DR 83171. This Standard was issued in draft form for comment as DR 83171.
AS 1720.1—1988
AS 1720.1—1988
Australian Standard
Australian Standard
®
®
SAA TIMBER STRUCTURES CODE
SAA TIMBER STRUCTURES CODE
Part 1—DESIGN METHODS
Part 1—DESIGN METHODS
Firs
First t publispublished as hed as AS CA65—1972.AS CA65—1972. Revis
Revised ed and redesignateand redesignated d AS 1720—1975.AS 1720—1975. Revis
Revised ed and redesignated AS and redesignated AS 1720.1—191720.1—1988.88. Incorporating:
Incorporating: Amdt 1—1993 Amdt 1—1993
PUBLISHE
PUBLISHED D BY STBY ST ANDARANDARDS AUSTRALIADS AUSTRALIA (STANDARD
(STANDARDS S ASSOCASSOCIATION OF IATION OF AUSTRALAUSTRALIA)IA) 1 THE CRESCENT, HOMEBUSH, NSW 2140 1 THE CRESCENT, HOMEBUSH, NSW 2140
ISBN 0 7262 5090 2 ISBN 0 7262 5090 2
PREFACE
PREFACE
This Standard was prepared by the Association’s Committee on Timber Engineering This Standard was prepared by the Association’s Committee on Timber Engineering to supersede AS 1720—1975,
to supersede AS 1720—1975, SAA SAA Timber EngineeTimber Engineering Code.ring Code.
In considering the revision of
In considering the revision of AS 1720—1975 the committee decAS 1720—1975 the committee decided that ided that it would beit would be appropriate if its subject matter and other material to be included in the revision was appropriate if its subject matter and other material to be included in the revision was divided into four parts as follows:
divided into four parts as follows: Part 1:
Part 1: Design methodsDesign methods (this Standa(this Standard)rd) Part 2:
Part 2: Timber propertiesTimber properties (in course of preparation)(in course of preparation) Part 3:
Part 3: Non-standard connectorsNon-standard connectors (in course of preparation(in course of preparation Part 4:
Part 4: Fire resistance of Fire resistance of timer structurtimer structureses (in course of preparation)(in course of preparation) Whil
While e this Standathis Standard rd is is primprimarilarily y conconcercerned ned with design with design memethodsthods, , it it alsalso o cocontaintainsns structural design properties for a modest range of timber species and metal connectors. structural design properties for a modest range of timber species and metal connectors. Se
Sectioction n 1 1 deadeals ls witwith h genegeneral ral mamattertters s sucsuch h as definitas definitions and ions and conconditioditions for ns for thethe application of this Standard. Design rules are given in Sections 2 to 7, with Section 2 application of this Standard. Design rules are given in Sections 2 to 7, with Section 2 containing the basic structural design properties of timber essential to the use of the containing the basic structural design properties of timber essential to the use of the Standard.
Standard.
Normal procedure for users is to note the general requirements of Section 1, obtain the Normal procedure for users is to note the general requirements of Section 1, obtain the ba
basic sic strstrucucturtural al dedesigsign n propropepertirties es frofrom m SeSectiction on 2 2 anand d thethen n to to proproceceed ed to to onone e of of Sections 3 to 7 depending on th type of element being designed.
Sections 3 to 7 depending on th type of element being designed. In general, the
In general, the simplesimpler design situations are coverr design situations are covered in ed in the main body othe main body o f the tf the t ext, andext, and acceptable procedures for detailed design situations
acceptable procedures for detailed design situations are given in the related appeare given in the related appendices.ndices. For ease of
For ease of use the use the appenappendices correldices correlate sequentiaate sequentially with the lly with the sectsections of ions of the text, i.e.the text, i.e. Append
Appendices A, B, C ices A, B, C etc are related to the Sections 1, 2, 3, etc are related to the Sections 1, 2, 3, etc, in the main body of etc, in the main body of thisthis text. It should be noted that Appendix A gives rules for the acceptance of timber text. It should be noted that Appendix A gives rules for the acceptance of timber structures based on proof and prototype testing.
structures based on proof and prototype testing.
The appendices, which form an integral part of this Standard, have been drafted in The appendices, which form an integral part of this Standard, have been drafted in mandatory terms to facilitate cross reference by Regulatory Authorities.
mandatory terms to facilitate cross reference by Regulatory Authorities. Design informa
Design information for tion for timber piles which was included in the timber piles which was included in the previous edition of thisprevious edition of this Standard is now provided in AS 2159,
Standard is now provided in AS 2159, SAA Piling Code.SAA Piling Code.
©
©Copyright Copyright STANSTANDARDS DARDS AUSAUSTRALTRALIAIA Users of
Users of StaStandards are ndards are remindreminded ed that copyright subsistthat copyright subsists s in all in all StaStandards Andards Australustralia publicatioia publications ns and software. Except where and software. Except where thethe Copyright Act allows and except where provided for below no publications or software produced by Standards Australia may be Copyright Act allows and except where provided for below no publications or software produced by Standards Australia may be rep
reproducroduced, stored, stored ed in in a a retretrierieval val syssystem in tem in any any forform m or or tratransmnsmittitted ed by by any means any means witwithout prior hout prior permpermissission ion in in wriwritinting g frofromm Standards Australia. Permission may be conditional on an appropriate royalty payment. Requests for permission and information on Standards Australia. Permission may be conditional on an appropriate royalty payment. Requests for permission and information on commerc
commercial softwarial software e royaltroyalties should be ies should be directdirected ed to the to the head office of head office of StandaStandards Australiards Australia.. St
Standaandards Austrds Australralia ia wilwill l permpermit up it up to to 10 10 percpercent of ent of the technthe technicaical l contcontent pages of ent pages of a a StStandaandard rd to to be be copicopied ed for for useuse exclus
exclusively in-housively in-house e by by purchasepurchasers of rs of the Standarthe Standard d withwithout payment out payment of a of a royaltroyalty y or advice to or advice to StandStandards Austraards Australia.lia. Standards Australia will also permit the inclusion of its copyright material in computer software programs for no royalty Standards Australia will also permit the inclusion of its copyright material in computer software programs for no royalty payment provide
payment provided d such programs are used such programs are used exclusexclusively in-housively in-house by e by the creators of the creators of the programs.the programs.
Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Stand
Standard is ard is amended or revised. The amended or revised. The number and date number and date of the of the StandaStandard should therefore be rd should therefore be clearlclearly identifiy identified.ed. The use
The use of of matmaterierial al in print form in print form or or in in compcomputeuter r sofsoftwatware programre programs s to to be be used commeused commercirciallally, y, wiwith th or or witwithout paymenthout payment, , or or inin commerci
CONTENTS
CONTENTS
Page Page
SECTI
SECTION ON 1. 1. SCOSCOPE APE AND ND GENERAGENERALL 1
1..1 1 SSCCO PO PE E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 1.
1.2 2 REREFEFERRENENCCED ED DDOCOCUMUMENENTS TS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 1.
1.3 3 NENEW MW MAATETERIRIALALS S ANAND MD METETHHODODS S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 1.
1.4 4 TITIMBMBER ER QQUAUALILITY . TY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 1.
1.5 5 GEGENENERARAL DL DESESIGIGN CN CONONSISIDEDERARATIOTIONS NS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 1.
1.6 6 DEDESISIGN GN ANAND SD SUUPEPERVRVISISIOION N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 1.
1.7 7 WOWORKRKMAMANSNSHIHIP ANP AND MD MAIAINTNTENENANANCE CE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 1 1..8 8 DDE FE FIINNIIT IT IOONNS S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 1 1..9 9 NNOOT AT AT IT IO N O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 1. 1.10 U10 UNNITITS S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 SECTI
SECTION ON 2. 2. BASIBASIC PROPC PROPERTIES OERTIES OF STRUCTF STRUCTURAURAL TIML TIMBERBER 2
2..1 1 GGE NE NE RE RAAL L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 2.
2.2 2 STSTRURUCTCTURURAL AL CLACLASSSSIFIFICICATATIOIONS . . . NS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 2.
2.3 3 BABASIC SIC WOWORKIRKING NG STRSTRESSESSES ES AND AND MOMODULDULUS US OF OF ELAELASTISTICITCITY Y 88 2
2..4 4 DDE SE SIIGGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 2.
2.5 5 MMODODIFIFICICAATITION ON FFACACTOTORS RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 SECTI
SECTION ON 3. 3. DESIDESIGN OF BASGN OF BASIC STRUIC STRUCTURCTURAL MAL MEMBERSEMBERS 3
3..1 1 GGE NE NE RE RAAL L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188 3
3..2 2 BBE AE AM DM DE SE SIIGGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188 3.
3.3 3 COCOLULUMMN DN DESESIGIGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2121 3.
3.4 4 TETENSNSIOION MN MEMEMBEBER R DEDESSIGIGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2222 3.
3.5 5 COCOMBMBININED ED BENBENDIDING NG ANAND AD AXIXIAL SAL STRTRESESSESES S . . . . . . . . . . . . . . . . . . . . . . 2222 SECTI
SECTION ON 4. 4. CONCONNECNECTIONTIONSS 4
4..1 1 GGE NE NE RE RAAL L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2233 4
4..2 2 NNAAI LI LE D E D JJOOI NI NT S T S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2233 4.
4.3 3 SCSCREREWWED ED JJOOININTS . . . . TS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2626 4.
4.4 4 BOBOLTLTED ED JJOIOINNTS TS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2727 4.
4.5 5 COCOACACH SH SCRCREWEWS S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3636 4.
4.6 6 SPSPLILIT-T-RIRINNG CG COONNNNECECTOTORS RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3737 4.
4.7 7 SHSHEAEAR PR PLALATE TE COCONNNENECCTOTORS RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3737 SECTI
SECTION ON 5. 5. PLYWPLYWOODOOD 5
5..1 1 GGE NE NE RE RAAL L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4400 5.
5.2 2 BABASISIC WC WORORKIKING NG STSTRERESSSSES ES ANAND SD STIFTIFFNFNESS ESS . . . . . . . . . . . . . . . . . . . . . . 4040 5
5..3 3 DDE SE SIIGGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4400 5.
5.4 4 MMODODIFIFICICAATITION ON FFACACTOTORS RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4040 5
5..5 5 JJOOI NI NT S T S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4400 SECTI
SECTION ON 6. 6. ROUNROUND D TIMBTIMBERSERS 6
6..1 1 GGE NE NE RE RAAL L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4433 6.
6.2 2 BABASISIC WC WORORKIKING NG STSTRERESSSSES ES ANAND SD STIFTIFFNFNESS ESS . . . . . . . . . . . . . . . . . . . . . . 4343 6
6..3 3 DDE SE SIIGGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4433 6.
6.4 4 ADADDIDITITIONONAL AL MOMODIDIFIFICACATITION ON FAFACTCTORORS S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4343 6.
6.5 5 DEDESISIGN GN DEDETATAILILS S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4343 SECTION
SECTION 7. 7. GLUED-LAMIGLUED-LAMINATED NATED CONSTRUCCONSTRUCTIONTION 7
7..1 1 GGE NE NE RE RAAL L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4455 7
7..2 2 DDE SE SIIGGN N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4455 7.
7.3 3 MMODODIFIFICICAATITION ON FFACACTOTORS RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4545 7.
Page Page
APPENDICES APPENDICES
A
A ACACCECEPTPTANANCE CE TETESTSTINING G OOF F TITIMMBEBER R SSTRTRUUCTCTURURES ES AANDND E L
E LE ME ME NE NT S T S . . . 4477 B
B BABASISIC C DEDESISIGN GN PRPROPOPERERTIETIES S OF OF STRSTRUCUCTUTURARAL L TITIMBMBER ER . . . . . . 5252 C
C DEDESISIGN GN OF OF BABASISIC C STSTRURUCTCTUURARAL ML MEMEMBEBERS RS . . . . . . . . . . . . . . . . . . . . . . 5353 D
D JJOOININTS TS IN IN TITIMMBEBER R STSTRRUCUCTUTURERES . . S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6767 E
E BUBUCKCKLILING NG STRSTRENGENGTH TH OF OF PLPLYWYWOOOOD D DIDIAPAPHRHRAGAGMS MS . . . . . . . . . . 7171 F
F COCONNNNECECTITIOONS NS FOFOR RR ROUOUNND TD TIMIMBEBERS . . . RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7676 G
G GLUEDGLUED-LAM-LAMINATINATED ED CONCONSTRUSTRUCTIONCTION—SP—SPECIAECIAL L CONCONDITIDITIONS ONS 7777 H
H REREFERFERENCENCED ED ANAND RD RELAELATED TED DODOCUCUMEMENTNTS . S . . . . . . . . . . . . . . . . . . . . . . . . . 7979 I
I NNOOT AT AT IT IO N O N AANND FD FA CA CT OT OR S R S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8800 IN
STANDARDS ASSOCIATION OF AUSTRALIA
STANDARDS ASSOCIATION OF AUSTRALIA
Austral
Australian ian StandStandardard TIMBER
TIMBER STRUCTSTRUCTURESURES
PART
PART 1:
1: DESI
DESIGN ME
GN METHOD
THODS
S
SECTISECTION 1. ON 1. SCOPSCOPE AND GE AND GENERAENERALL
1.1 SCOPE.
1.1 SCOPE. This Standard sets out the design methodsThis Standard sets out the design methods for the structural use of timber which are based on the for the structural use of timber which are based on the princi
principles ofples of strucstructural mechatural mechanicsnics andand on data estabon data establishedlished by
by resresearearch. The ch. The StaStandandard is rd is intintendended for ed for use in use in thethe design or appraisal of structural elements comprised of design or appraisal of structural elements comprised of tim
timber ber or or woowood d proproducducts ts and and of of strstructuctureures s comcompriprisedsed su
subsbstatantntiaialllly y of of titimbmberer. . To To ththis is enend, d, ththe e StStanandadardrd provides design data for sawn timber, laminated timber, provides design data for sawn timber, laminated timber, ti
timbmber er in in popole le foformrm, , plplywywooood d anand d vavaririouous s tytypepes s of of faste
fasteningsnings. In . In additaddition, it ion, it providprovides es methomethods of ds of test fortest for com
componponentents s or or assassembemblielies s of of uncunconvonvententionional al desdesignign which may not
which may not be readily amenable to be readily amenable to detaildetailed analysied analysis.s. For ease of use, the simpler design situations are covered For ease of use, the simpler design situations are covered in the main body of the text. Related appendices, which in the main body of the text. Related appendices, which for
form m an an intintegregral part al part of of the the StaStandandard, give rd, give accaccepteptablablee proce
procedures for dures for detaidetailed design led design situatsituations.ions. 1.2 REFERENCED DOCUMENTS.
1.2 REFERENCED DOCUMENTS. A list with titlesA list with titles of the documents referred to in this Standard is given in of the documents referred to in this Standard is given in Appendix H.
Appendix H. 1.
1.3 3 NENEW W MAMATETERIRIALALS S ANAND D MEMETHTHODODS.S. ThisThis Standard shall not be interpreted to prevent the use of Standard shall not be interpreted to prevent the use of mat
materierial al or or of of metmethodhods s of of desdesign or ign or conconstrstructuction ion notnot specifically referred to herein. Nor is the classification of specifically referred to herein. Nor is the classification of ti
timbmberers s ininto to ststrerengngth th grgrououps ps (C(Clalaususe e 1.1.4) 4) or or ththeieirr grouping for joint design (Clause 4.1) to be interpreted grouping for joint design (Clause 4.1) to be interpreted as precluding the use of design stresses or other design as precluding the use of design stresses or other design data derive
data derived for d for a a particparticular timber or grade of ular timber or grade of timber ontimber on the basis of authoritative research information.
the basis of authoritative research information. NOT
NOTE: E: It usuallIt usually y wilwill l be be necnecessessary to ary to seeseek k apprapproval from oval from thethe Building Authority or other appropriate Regulatory Authority for the Building Authority or other appropriate Regulatory Authority for the use of new materials or methods.
use of new materials or methods. 1.4
1.4 TIMBTIMBER QUALITER QUALITY.Y. All timber used in accordanceAll timber used in accordance with this Standard shall comply with the requirements of with this Standard shall comply with the requirements of appropriate Australian Standards. The following points appropriate Australian Standards. The following points shall be noted:
shall be noted: (a)
(a) GeneralGeneral. Tables 2.1 and 2.2 herein and AS 1720.2,. Tables 2.1 and 2.2 herein and AS 1720.2, lis
list t comcommon mon spespeciecies s useused d for for strstructucturaural l purpurposposeses together with their
together with their strengthstrength classifications and classifications and designdesign density.
density. (b)
(b) Timber classificationTimber classification. Timber species are classified. Timber species are classified iinntto o sseevveen n ssttrreennggtth h ggrroouupps s SS1 1 tto o SS7 7 iin n tthhee unseasoned condition and eight strength groups SD1 unseasoned condition and eight strength groups SD1 to SD8 in the seasoned condition. The timber species to SD8 in the seasoned condition. The timber species are also classified into six joint groups J1 to J6 if are also classified into six joint groups J1 to J6 if used unseasoned, and JD1 to JD6 if used seasoned. used unseasoned, and JD1 to JD6 if used seasoned. Sawn structural timber, pole timbers and plywood Sawn structural timber, pole timbers and plywood are classified into 12 stress grades F2 to F34 when are classified into 12 stress grades F2 to F34 when these have been graded
these have been graded accoraccording to ding to the appropriathe appropriatete gradin
grading g StandaStandard rd or or other other approvapproved ed specispecificatfication.ion.
(c)
(c) StresStress s grade grade and and specispecies es identiidentificatification.on. StructuralStructural timber used in conjunction with this Standard shall timber used in conjunction with this Standard shall have its stress grade identified.
have its stress grade identified. Fo
For r mamany ny pupurprpososes es it it mamay y alalso so be be nenececessssarary y toto sp
spececifify y a a papartrticiculular ar spspececieies. s. WhWhen en a a papartirticuculalarr speci
species es is is specispecified the fied the specispecificatification shall on shall requirrequiree that all pieces of timber be suitably identified as to that all pieces of timber be suitably identified as to species.
species. NOTES: NOTES: 1.
1. The desigThe design n propproperterties ies recrecommeommendended d in in thithis s StaStandandard rd havhavee been chosen on the assumption that structures of unseasoned been chosen on the assumption that structures of unseasoned timber that are allowed to dry
timber that are allowed to dry will not receive their full designwill not receive their full design load until a period of air drying for at least 2 weeks has taken load until a period of air drying for at least 2 weeks has taken pla
place. ce. FreFreshlshly y sawsawn n timtimber which ber which is is unsunseaseasoneoned, d, or or hashas recently been treated with waterborne chemicals, tends to have recently been treated with waterborne chemicals, tends to have a reduced resistance and stiffness to sustained loads during the a reduced resistance and stiffness to sustained loads during the initia
initial l drying period.drying period. 2.
2. UsuUsuallally, only y, only a a limlimiteited d numbnumber of er of the timbthe timber specier species andes and stress grades listed in this Standard will be readily available at stress grades listed in this Standard will be readily available at any particular place and time.
any particular place and time. (d)
(d) Change of grade or durability.Change of grade or durability. Care shall be takenCare shall be taken to
to accaccounount t for for any changany change e in in orioriginginal al gragradinding g oror pr
preseserervavatitive ve tretreatatmement nt as as a a reresusult lt of of sasawiwing ng oror dress
dressing. Regradining. Regrading will g will be necessabe necessary ry if if membemembersrs are
are longitlongitudinaludinally ly resawresawn. n. MachiMachining may ning may removeremove pre
preserservatvative ive envenveloelopes pes renrenderdering ing the the tretreatmatmentent ineffective.
ineffective. (e)
(e) Special provisions.Special provisions. DesDesign ign loaloads ds for for timtimber ber joijointsnts and design rules for
and design rules for notchenotched beams given d beams given herein areherein are ba
basesed d on on ththe e asassusumpmptiotion n ththat at ththerere e arare e no no loloososee knots, severe sloping grain, gum veins, gum or rot knots, severe sloping grain, gum veins, gum or rot pocke
pockets, ts, lyctuslyctus-susc-susceptibleptible e sapwosapwood, od, holes holes or or splitssplits in the
in the near vicinnear vicinity of ity of any connectorany connectors or s or notch rootsnotch roots.. (f)
(f) TreatTreated ed timbertimber.. TimbTimber, er, tretreateated d by by impimpregregnatnationion with waterborne chemicals such as preservatives, is with waterborne chemicals such as preservatives, is classified as unseasoned timber unless seasoning is classified as unseasoned timber unless seasoning is specified.
specified. NOT
NOTE: E: WherWhere e the the matmaterierial al is is resreseaseasonedoned, , regregradirading ng wouwouldld normall
normally y be required.be required.
1.5 GENERAL DESIGN CONSIDERATIONS. 1.5 GENERAL DESIGN CONSIDERATIONS. 1.5
1.5.1 .1 LoaLoadsds.. 1.5.1.1
1.5.1.1 General.General. A A sstrtrucuctuturere, , anand d aany ny papart rt of of aa str
structuctureure, , shashall ll be be desdesignigned ed for for the the loaloads ds spespecifcified ied inin AS
AS 1170 or such other loa1170 or such other loading Standing Standard as isdard as is appropappropriateriate to
to ththe e enend-d-ususe e of of a a spspececifific ic ststruructcturure e or or papart rt of of aa structure.
structure. 1.5.1.2
1.5.1.2 Load duration.Load duration. The significance of duration of The significance of duration of loading in the design of timber structures shall be noted loading in the design of timber structures shall be noted and parti
and particulcular ar attattentention paid ion paid to to the term the term ‘du‘duratration ion of of loading’. (For the definition of this term see Clause 1.8.2 loading’. (For the definition of this term see Clause 1.8.2 and for further information Clause 2.5.1.)
1.5.2 Design methods. 1.5.2 Design methods. 1.5.2.1
1.5.2.1 General.General.A structure, or part of a structure, orA structure, or part of a structure, or an
an indindiviividuadual l strstructucturaural l eleelemenment t shashall ll be be capcapablable e of of sustaining the most adverse likely combination of loads. sustaining the most adverse likely combination of loads. Every part of the structure shall be proportioned so that Every part of the structure shall be proportioned so that the permissible stresses determined in accordance with the permissible stresses determined in accordance with this Standard are not exceeded.
this Standard are not exceeded. NOTE: Some of the clauses of this
NOTE: Some of the clauses of this StandaStandard have been rd have been simplsimplified asified as far
far as as prpracactiticacablble e to to pepermirmit t rarapipid d cacalclcululatatioion n anand d mamay y as as aa con
conseseququenence ce ininvolvolve ve sosome me dedegregree e of of coconsnserervavatitismsm. . WhWhereree app
appropropririatate, e, momore re refrefinined ed dedesisign gn memeththods ods arare e gigiveven n in in ththee appendices which form an integral part of this Standard.
appendices which form an integral part of this Standard. 1.5.2.2
1.5.2.2 Stress analysis.Stress analysis. All stresses shall be calculatedAll stresses shall be calculated on
on ththe e babassis is of of elelasastitic c ththeoeory ry in in orordeder r ththaat t ththee re
reququirirememenents ts of of ththis is cocode de in in reregagard rd to to pepermirmissssibiblele stresses may be satisfied with regard to the load effects stresses may be satisfied with regard to the load effects at
at anany y papartrticiculular ar lolocacatitionon. . FoFor r exexamamplple e ththe e apapplplieiedd bendi
bending ng momenmomentt M M and and sheshear ar forforcece V V on a beam of on a beam of recta
rectangular cross-sengular cross-section shall ction shall be be checkchecked ed by—by—
M M ≤≤ ((bd bd 22 /6) /6)F F bb . . . . . . (1(1.1.1)) V V ≤≤ (2(2bd bd /3) /3)F F ss . . . . . . (1(1.2.2)) where where b
b andand d d = = the breathe breadth and ddth and depth of the mepth of the memberember
F
F bb andand F F ss = = ththe e pepermrmisissisiblble e dedesisign gn ststreresssses es inin bending and shear.
bending and shear. Whe
When n sevseveraeral l matmaterierials are als are gluglued ed togtogethether er to to forform m aa structural element, stresses may be calculated from an structural element, stresses may be calculated from an equivalent transformed section, where the transformation equivalent transformed section, where the transformation is made with respect to the moduli of elasticity.
is made with respect to the moduli of elasticity. 1.5.2.3
1.5.2.3 Experimentally based design.Experimentally based design. Where a structureWhere a structure or
or a a ststruructcturural al elelememenent t is is of of an an ununcoconvnvenentiotionanal l oror complex nature, and it is demonstrated by the full-scale complex nature, and it is demonstrated by the full-scale tes
tests ts spespecifcified ied in in AppAppendendix ix A A thathat t reqrequiruiremeements nts forfor stren
strength, gth, deformdeformation, stability and ation, stability and servicserviceabilieability ty areare satisfied, the corresponding design requirements of this satisfied, the corresponding design requirements of this Standard shall be deemed also to have been satisfied. Standard shall be deemed also to have been satisfied. 1.5.3 Other design considerations.
1.5.3 Other design considerations. 1.5.3.1
1.5.3.1Stability.Stability.The stability of the The stability of the structstructure as a ure as a wholewhole shall be investigated, and mass and anchorage shall be shall be investigated, and mass and anchorage shall be provided so that the structure is in overall equilibrium. provided so that the structure is in overall equilibrium. NOTE: Suitable recommendations for this purpose will be given in NOTE: Suitable recommendations for this purpose will be given in AS 1170.1.
AS 1170.1. 1.5.3.2
1.5.3.2 Buckling restraints.Buckling restraints. Where there may be someWhere there may be some dou
doubt bt as as to to the the effeffectectiveivenesness s of of bucbucklikling ng resrestratraintints,s, app
appropropriariate te comcomputputatiationsons, , sucsuch h as as thothose se indindicaicated ted inin Paragraph C7, Appendix C, shall be made to check the Paragraph C7, Appendix C, shall be made to check the stiffness and strength of the restraints.
stiffness and strength of the restraints. 1.5.3.3
1.5.3.3 Erection and other extraneous forces.Erection and other extraneous forces. AdequateAdequate pro
provisvision shall ion shall be made be made to to resresist ist the latethe lateral and ral and othotherer forces that can occur during the transport of structural forces that can occur during the transport of structural elements, and during and after the erection of a structure. elements, and during and after the erection of a structure. 1.5.3.4
1.5.3.4SeconSecondarydary stresstresses.ses.CarefCareful ul consiconsideratiderationon shall beshall be given to possible secondary stresses. Where these cannot given to possible secondary stresses. Where these cannot be reduced to negligible proportions, suitable provisions be reduced to negligible proportions, suitable provisions in the design or some reduction in permissible primary in the design or some reduction in permissible primary stresses shall be made.
stresses shall be made. 1.5.3.5
1.5.3.5 Shrinkage.Shrinkage. WheWhen n usiusing ng unsunseaseasoneoned d timtimberber,, consideration shall be given to the effects of shrinkage. consideration shall be given to the effects of shrinkage. Detai
Detailing of ling of the the joints shaljoints shall l not restrain shrinknot restrain shrinkage whereage where splitting could render the joint ineffective. Consideration splitting could render the joint ineffective. Consideration sha
shall ll alsalso o be be givgiven en to to arcarchithitectecturaural l detdetailailing ing to to avoavoidid
da
damamage ge or or ununsisighghtltly y apappepeararananceces s reresusultltining g frfromom differential movement on structural members caused by differential movement on structural members caused by timber shrinkage. These comments also apply to timber timber shrinkage. These comments also apply to timber which has
which has been impregnatebeen impregnated d with waterborne chemicalwith waterborne chemicalss and which has not been reseasoned after treatment. and which has not been reseasoned after treatment.
NOTE: For most timbers the magnitude of shrinkage is in the range NOTE: For most timbers the magnitude of shrinkage is in the range of 0.1% to 0.3% in th
of 0.1% to 0.3% in the direction of the we direction of the wood grain and ood grain and 2% to 10%2% to 10% transve
transverse to rse to this direction. Informatiothis direction. Information n on on shrinkashrinkage ge for specificfor specific species can be obtained from:
species can be obtained from: (a
(a) ) KIKINGNGSTSTONON, , R.R.S.S.T. T. and and RISRISDODON N C.C.J.J.E. E. ‘S‘Shrihrinknkage andage and Density of Australian and Other South-west Pacific Woods’. Density of Australian and Other South-west Pacific Woods’. Div
Divisiision on of of ForForest est ProdProductucts s TecTechnolhnologicogical al PapPaper er No No 13,13, CSIRO, 1961.
CSIRO, 1961. (b)
(b) BUDGENBUDGEN, B. ‘, B. ‘ShrinkaShrinkage and ge and DensitDensity of y of some Aussome Australiatralian ann andd South-e
South-east Asian ast Asian TimberTimbers’. s’. DivisDivision ion of of BuildiBuilding ng ReseaResearchrch Technological Paper (Second Series) No 38, CSIRO, 1981. Technological Paper (Second Series) No 38, CSIRO, 1981. 1.5.3.6
1.5.3.6 Deformations. Deformations.Timber Timber structstructuresures shallbeshallbe desigdesignedned so that deformat
so that deformations incurrions incurreded in-serin-service do not impairvice do not impair thethe strength and serviceability of the structures or any part strength and serviceability of the structures or any part thereof, nor cause damage to other building components. thereof, nor cause damage to other building components. Timber members shall have sufficient stiffness so that Timber members shall have sufficient stiffness so that undesirable deflections and vibrations are avoided. undesirable deflections and vibrations are avoided.
NOTES: NOTES: 1.
1. The responsThe responsibiliibility for deflection and stiffnesty for deflection and stiffness limits should ress limits should restt with the design engineer.
with the design engineer. 2.
2. In In comcomputiputing ng desdesign defleign deflectictionsons, , it should be it should be appapprecreciatiated ed thathatt tim
timber ber is is varvariabiable le witwith h resrespecpect t to to its its strstructuctural properural propertieties. s. ItIt should also be noted that the moduli given in Table 2.3 refer to should also be noted that the moduli given in Table 2.3 refer to design values for groups of timber. If for some reason (e.g. to design values for groups of timber. If for some reason (e.g. to specify camber) accurate predictions of deflection are required, specify camber) accurate predictions of deflection are required, detail
detailed information relevant to ed information relevant to the specific species of the specific species of timbertimber under consideration should be used.
under consideration should be used. 1.5.3.7
1.5.3.7Timber dimensions for engineering calculations.Timber dimensions for engineering calculations.
Al
All l enengigineneererining g cacalclcululatatioions ns shshalall l be be babasesed d on on ththee minimum net cross-section. Such calculations shall not minimum net cross-section. Such calculations shall not be based on the nominal cross-section.
be based on the nominal cross-section. 1.5.3.8
1.5.3.8 TimbeTimber in r in naturanatural pole l pole form.form. For logs or polesFor logs or poles complying with the quality requirements of AS 2209, the complying with the quality requirements of AS 2209, the cor
corresresponpondendence ce betbetweeween n strstrengength th grogroups ups and and strstressess grades is as shown in Table 6.1.
grades is as shown in Table 6.1. 1.5.3.9
1.5.3.9Biological deterioration.Biological deterioration.Generally, timber underGenerally, timber under cover and in well ventilated conditions and not in contact cover and in well ventilated conditions and not in contact with the ground or free water, is not subject to fungal with the ground or free water, is not subject to fungal attack. However, such timber may be subject to termite attack. However, such timber may be subject to termite attack and to attack by other insects in parts of Australia. attack and to attack by other insects in parts of Australia. If conditions favourable for biological attack exist, then If conditions favourable for biological attack exist, then ste
steps ps shashall ll be be taktaken en to to elieliminminate the ate the hazhazardards. This s. This isis particularly important in structures where there is no load particularly important in structures where there is no load sharing capacity, e.g. large trusses.
sharing capacity, e.g. large trusses. 1.6 DESIGN AND SUPERVISION. 1.6 DESIGN AND SUPERVISION. 1.6.1 Design.
1.6.1 Design. The design of timber structures to whichThe design of timber structures to which thi
this s StaStandandard rd appapplielies, s, incincludluding ing the the spespecifcificaicatiotion n of of materials and any protective treatment, shall be carried materials and any protective treatment, shall be carried out in accordance with the requirements of this Standard out in accordance with the requirements of this Standard and the relevant documents in Appendix H.
and the relevant documents in Appendix H. NOT
NOTE: E: The desigThe design n of of a a strstructucture complyure complying ing witwith h thithis s StaStandandardrd should be the responsibility of a design engineer experienced in the should be the responsibility of a design engineer experienced in the design of such structures.
design of such structures. 1.6.2 Supervision.
1.6.2 Supervision. The fabrication and erection of theThe fabrication and erection of the timber structures or the parts of structures to which this timber structures or the parts of structures to which this Standard applies shall be supervised to ensure that all of Standard applies shall be supervised to ensure that all of th
the e rereququireiremementnts s of of ththe e dedesisign gn arare e sasatitisfsfieied d in in ththee completed structure.
completed structure. NOT
NOTE: E: The The supsupervervisiision on of of fabfabricricatiation on and and ereerectiction on of of timtimberber struct
structures should be ures should be the responsibthe responsibility of ility of a a supervisupervision engineersion engineer experienced in the fabrication and erection of such structures. experienced in the fabrication and erection of such structures.
COPYRIGHT COPYRIGHT
1.7 WORKMANSHIP AND MAINTENANCE. 1.7 WORKMANSHIP AND MAINTENANCE. 1.7.1 General.
1.7.1 General. The following requirements are intendedThe following requirements are intended to
to hehelp lp eensnsurure e ththat at a a ststrurucctuture re or or elelememenent t whwhenen fa
fabrbricicatated ed peperfrformorms, s, anand d wiwill ll cocontntininue ue to to peperfrfororm,m, struc
structurallturally in y in thethe mannemanner r intenintended by the designer of theded by the designer of the structure.
structure. 1.7.2 Moistur
1.7.2 Moisturee contecontent.nt. When structures or elements areWhen structures or elements are to be fabricated with seasoned timber in situations where to be fabricated with seasoned timber in situations where dim
dimensensionional al stastabilbility ity is is cricritictical, al, the the desdesignigner er of of thethe structure shall
structure shall ascertain theascertain the average equilibrium moaverage equilibrium moistureisture content for the environment in which the structures or content for the environment in which the structures or elements are to be erected, and shall specify that each elements are to be erected, and shall specify that each pie
piece ce of of timtimber used ber used shashall ll havhave e an an aveaveragrage e moimoistusturere content at the time of fabrication that is within 3 percent content at the time of fabrication that is within 3 percent of the equilibrium value.
of the equilibrium value. NOTES:
NOTES: 1.
1. DefDefiniinitiotions used in this Stans used in this Standarndard for the moistud for the moisture re contcontent of ent of seasoned and unseasoned timber are given in Clause 1.8.2. For seasoned and unseasoned timber are given in Clause 1.8.2. For int
intermermediediate ate valvalues ues of of moimoistusture re contcontentent, , the the terterm m ‘pa‘partirtiallallyy seasoned timber’ will be used.
seasoned timber’ will be used. 2.
2. InformaInformation on equilibrium moisture conttion on equilibrium moisture content values in timbersent values in timbers lo
locacateted d in in AuAuststralralia ia cacan n be be obtobtaiainened d frfrom om ththe e folfollowlowiningg references:
references: (a)
(a) FINFINIGHIGHAN, R. ‘MoiAN, R. ‘Moistusture Contere Content Prednt Predictictions foions for r EigEightht Seaso
Seasoned ned Timbers under Sheltered Outdoor Timbers under Sheltered Outdoor ConditiConditions inons in Austra
Australia and lia and New Guinea’. Division of Forest New Guinea’. Division of Forest ProducProductsts Technological Paper No 44, CSIRO, 1966.
Technological Paper No 44, CSIRO, 1966. (b)
(b) BRAGG, BRAGG, C. ‘AC. ‘An Eqn Equilibruilibrium ium MoistuMoisture re Content Content Survey of Survey of Ti
Timbmber er in in QuQueeeensnslaland’nd’. . QuQueeeensnslaland nd DeDepapartrtmement nt of of Forestry Technical Paper No 40, QFD, 1986.
Forestry Technical Paper No 40, QFD, 1986. 1.7.3 Corrosion.
1.7.3 Corrosion. The designer of The designer of the structurthe structure shall e shall taketake due account of any possible corrosive effects on metal due account of any possible corrosive effects on metal connectors.
connectors.
NOTE: Information on the protection of steel can be obtained from NOTE: Information on the protection of steel can be obtained from AS 2312.
AS 2312.
1.7.4 Maintenance.
1.7.4 Maintenance. Where in the opinion of the designerWhere in the opinion of the designer of
of a a ststruructcturure e spspececiaial l mamainintetenanancnce e is is rereququirired ed fofor r aa st
strucructuture re to to fufulflfil il itits s inintetendnded ed fufuncnctitionon, , ththen en susuchch maintenance shall be specified in relevant documents. maintenance shall be specified in relevant documents. 1.8 DEFINITIONS.
1.8 DEFINITIONS. For the For the purpurpospose e of of thithis s StaStandandard,rd, the definitions given in AS 01 and those below apply. the definitions given in AS 01 and those below apply. 1.8.1 Administrative definitions.
1.8.1 Administrative definitions.
Building Authority or
Building Authority or other Regulatory Authorityother Regulatory Authority— body— body ha
haviving ng ststatatututory ory popowewers rs to to cocontntrorol l ththe e dedesisign gn anandd erection of buildings or structures, including scaffolding, erection of buildings or structures, including scaffolding, in the area in which the building or structure concerned in the area in which the building or structure concerned is to be erected.
is to be erected.
Engineer
Engineer —pers—personon qualiqualifiedfied for for CorporCorporateate MembeMembersrshiphip of of The Institution of Engineers, Australia.
The Institution of Engineers, Australia.
NOTE: The definition of engineer does not require that the person NOTE: The definition of engineer does not require that the person be a Corporate Member of The Institution of Engineers.
be a Corporate Member of The Institution of Engineers. 1.8.2 Technical definitions.
1.8.2 Technical definitions.
Basic working
Basic working stressstress—stress appropriate to an arbitrarily—stress appropriate to an arbitrarily chosen, but constant, basic reference set of conditions. It chosen, but constant, basic reference set of conditions. It is
is dedeririveved d frofrom m ththe e knknowown n ststrerengngth th prpropoperertities es of of aa timber, due allowance having been made for such factors timber, due allowance having been made for such factors as
as materimaterial al variabvariability, long-duratility, long-duration loading, grade ion loading, grade of of timber, and a safety factor.
timber, and a safety factor.
Basic
Basic working working load load for for connectorsconnectors—load —load approappropriate topriate to an arbitrarily chosen, but constant, basic reference set of an arbitrarily chosen, but constant, basic reference set of co
condndititioionsns. . It It is is dederivrived ed frfrom om ththe e knknowown n ststrerengngthth properties of the timber-connector system, due allowance properties of the timber-connector system, due allowance having been made for such factors as material variability, having been made for such factors as material variability,
lon
long-dg-durauratiotion n loaloadinding, g, gragrade de of of timbtimber, er, and and a a safsafetyety factor.
factor.
Colla
Collapse-spse-suscepusceptible tible timbetimber r —t—timimbeber r fofor r whwhicich h ththee shrin
shrinkagekage valuevalues before ands before and after recondiafter reconditionintioning differ byg differ by more than 2 percent.
more than 2 percent.
NOTE: Information on shrinkage values can be obtained from: NOTE: Information on shrinkage values can be obtained from: (a
(a) ) KIKINGNGSTSTONON, R, R.S.S.T.T. a. and Rnd RISISDODON CN C.J.J.E.E. ‘. ‘ShShririnkankage ge anandd Den
Densitsity y of of AusAustratralialian n and and OthOther er SouSouth-wth-west est PacPacifiificc Woods’. Divisi
Woods’. Division on of of ForesForest Products t Products TechnoTechnological Paperlogical Paper No 13, CSIRO, 1961.
No 13, CSIRO, 1961. (b)
(b) BUDBUDGENGEN, , B. B. ‘Sh‘Shrinrinkage kage and and DenDensitsity y of of somsome e AusAustratralialiann and
and SoutSouth-eah-east st AsiAsian an TimTimberbers’. s’. DivDivisiision on of of BuiBuildildingng Res
Researearch ch TecTechnolhnologicogical al PapPaper er (Se(Second cond SerSeriesies) ) No No 38,38, CSIRO, 1981.
CSIRO, 1981. Corewood
Corewood —timber adjacent to or including the pith, that—timber adjacent to or including the pith, that is of density less than 80 percent that of the density of is of density less than 80 percent that of the density of mature trees.
mature trees. NOTE: For planta
NOTE: For plantation grown softwotion grown softwoods, corewods, corewood may ood may be be avoideavoidedd by excluding all timber within a radius of 50 mm from the pith, that by excluding all timber within a radius of 50 mm from the pith, that has a ring width greater than 6 mm.
has a ring width greater than 6 mm. Duration
Duration of of loadingloading—period during which a member, a—period during which a member, a structural element or a complete structure is stressed as structural element or a complete structure is stressed as a consequence of the loads applied.
a consequence of the loads applied. NOTES:
NOTES: 1.
1. For the purpFor the purposeoses of s of intinterprerpretaetatiotion in n in the use of the use of loaload-dud-duratrationion factors in this Standard, see Clause 2.5.1.
factors in this Standard, see Clause 2.5.1. 2.
2. The strengThe strength propertith properties of timber under load are time depees of timber under load are time dependent.ndent. In-grade
In-grade verificationverification — — veveririficficatatioion n of of ththe e dedesisigngn pro
properpertieties s assassignigned to ed to strstress gradess graded timbeed timber. r. WheWherere ap
applplicicabablele, , ththesese e prpropoperertities es shshalall l be be evevalaluauateted d inin accordance with AS 4063.
accordance with AS 4063. NOTE:
NOTE: Where AS 4063 is employed to assign desiWhere AS 4063 is employed to assign design propertiegn properties tos to str
stress graded ess graded timtimberber, , the the strstress ess gragrading ding proproceducedures res shoshould uld bebe subjec
subjected ted to to a continuing a continuing qualitquality-contry-control ol program.program. Permissible stress
Permissible stress—maximum stress to be used in the—maximum stress to be used in the design of an element of a structure. It is obtained from design of an element of a structure. It is obtained from the basic working stress appropriately modified for the the basic working stress appropriately modified for the type of structure and service conditions.
type of structure and service conditions.
Seaso
Seasonedned timbetimber r —wo—woodod in whiin whichch thethe maxmaximuimumm moimoistusturere co
contntenent t ananywywhehere re wiwiththin in a a pipiecece e dodoes es nonot t exexceceeded 15 percent.
15 percent.
NOTE: Seasoned timber is sometimes referred to as ‘dry’ or NOTE: Seasoned timber is sometimes referred to as ‘dry’ or ‘air-dried’ timber. It includes kiln-dried timber.
dried’ timber. It includes kiln-dried timber. Str
Stress ess gragradede—cl—classassificificatiation on of of timtimber ber for for strstructucturaurall purposes by means of either visual or machine grading purposes by means of either visual or machine grading to indicate the basic working stresses and stiffnesses to to indicate the basic working stresses and stiffnesses to be used for structural design purposes.
be used for structural design purposes.
NOTE: The stress grade is designated in a form such as ‘F7’ which NOTE: The stress grade is designated in a form such as ‘F7’ which indicates that, for such a grade of material, the basic working stress indicates that, for such a grade of material, the basic working stress in bending is approximately 7 MPa.
in bending is approximately 7 MPa. Uns
Unseaseasoneoned d timtimber ber ——wowood od in in whwhicich h ththe e aaveveraragege moisture content of each piece exceeds 25 percent. moisture content of each piece exceeds 25 percent.
NOT
NOTE: E: UnsUnseaseasoned oned timtimber ber is is somsometietimes mes refreferreerred d to to as as ‘gre‘green’en’ timber.
timber.
1.9 NOTATION.
1.9 NOTATION. Except where specifically defined inExcept where specifically defined in a particular clause, the quantity symbols and factors used a particular clause, the quantity symbols and factors used in this Standard are listed in Appendix I.
in this Standard are listed in Appendix I. 1.1
1.10 0 UNIUNITSTS.. UnUnleless ss ototheherwrwisise e ststatateded, , ththe e ununitits s of of mea
measursuremeement nt useused d in in thithis s StaStandandard rd are are in in accaccordordancancee with the International System of Units (SI).
with the International System of Units (SI). NO
NOTETE: : In In gegeneneraral l N N (n(newewtoton)n), , mm mm (m(milillilimemetrtre) e) anand d MPMPaa (megapascal) are appropriate units to be used.
SECTI
SECTION 2. ON 2. BASIBASIC PROPERC PROPERTIES OF STRUCTIES OF STRUCTURATURAL L TIMBETIMBERR
2.1
2.1 GENGENERAERAL.L. PerPermismissibsible le strstressesses es for for strstructucturaurall ti
timbmber er shshalall l be be obobtatainined ed ththrorougugh h momodidifyfyining g babasisicc wor
workinking g valvalues ues by by facfactors tors appappropropriariate te to to the the serservicvicee conditions. This general procedure applies to all types of conditions. This general procedure applies to all types of str
structucturaural l timtimberber, , incincludluding ing sawsawn n timtimberber, , lamlaminainatedted timber, natural round timber and plywood.
timber, natural round timber and plywood. 2.2 STRUCTURAL CLASSIFICATIONS.
2.2 STRUCTURAL CLASSIFICATIONS. Tables 2.1Tables 2.1 and
and 2.2 2.2 lislist t the the strstructucturaural l claclassissificficatiations ons and and desdesignign densi
densities (for ties (for compucomputing dead ting dead loadsloads) of ) of timbetimber r specispecieses and species groups that are commonly used in Australia. and species groups that are commonly used in Australia. Th
The e dadata ta gigiveven n in in TaTablbles 2.1 es 2.1 anand d 2.2.2 2 arare e tatakeken n frfromom ot
otheher r StStanandadardrds, s, in in papartrticiculular ar AS AS 20208282, , AS AS 22220909,, AS 2269, AS 2858 and AS 2878; any changes to these AS 2269, AS 2858 and AS 2878; any changes to these Sta
Standandards shall rds shall be be taktaken en to to supsupersersede the ede the datdata a citciteded herein. In addition, any stress grades evaluated through herein. In addition, any stress grades evaluated through in-grade testing of full size structural material shall be in-grade testing of full size structural material shall be taken to supersede all the above information.
taken to supersede all the above information. NOTES:
NOTES: 1.
1. The densiThe density of ty of unsunseaseasoneoned d timtimber dependber depends s on on its moisits moisturturee content which reduces as the timber dries. The values given in content which reduces as the timber dries. The values given in Tables 2.1 and 2.2 have been computed on the basis that the Tables 2.1 and 2.2 have been computed on the basis that the per
percencentage satutage saturatration of ion of the timbethe timber r is 45 is 45 and 80 and 80 percpercent forent for softwo
softwoods ods and and hardwoohardwoods ds respecrespectively.tively. 2.
2. ThThe e vavalulues es of densof densitity y gigiveven n in Tablin Tables 2.1 es 2.1 anand d 2.2.2 2 do do notnot rep
represresent ent aveaverage rage valvalues ues for for the speciethe species s indindicaicatedted; ; thethey y areare int
intendended ed for use for use in in comcomputiputing ng the dead the dead loaloading imposding imposed ed byby timber.
timber. 3.
3. ThThe e modmodululi i of of elelasastiticicity ty gigiveven n in in TaTable 2.3 ble 2.3 arare e inintetendended d toto rep
represresent ent aveaveragrage e valvalues ues excexcept ept whewhere re spespeciecies s mixtmixtureures s oror speci
species with es with high variabilihigh variability ty are concerneare concerned; d; in the in the latter case, thelatter case, the cited moduli of elasticity are less than the average values. cited moduli of elasticity are less than the average values. 4.
4. A more extensivA more extensive list of timber species and spece list of timber species and species groups willies groups will be given in AS 1720.2.
be given in AS 1720.2. 2.3
2.3 BASBASIC IC WOWORKRKINGING STSTRESRESSESESS ANDAND MOMODULDULUSUS OF ELASTICITY.
OF ELASTICITY. 2.3
2.3.1 .1 BasBasic ic worworkinking g strstressesses es parparallallel el to to gragrain, in, andand shear stresses in beams.
shear stresses in beams. These basic These basic workinworking g stresstressesses are given in Table 2.3 for the various stress grades. are given in Table 2.3 for the various stress grades. 2
2..33..2 2 BBaassiic c wwoorrkkiinng g sstrtreesss s in in ccoommpprreessssioionn perpendicular to the grain and shear stress at joint perpendicular to the grain and shear stress at joint details.
details. ThThesese e babasisic c woworkrkining g ststreresssses es arare e gigiveven n inin Table 2.4 for each strength group and are applicable to Table 2.4 for each strength group and are applicable to all stress grades within the strength group.
all stress grades within the strength group.
2.3.3 Basic working stress in compression at an angle 2.3.3 Basic working stress in compression at an angle to the grain.
to the grain. The basic working stress in compression atThe basic working stress in compression at an
anglgles es to to ththe e grgraiain n ototheher r ththan an 00°° anand d 9090°° shashall ll bebe d
deennootteed by d by aannd shd shaalll be cl be caallccuullaatteed frd froom thm thee Hankinson formula Hankinson formula . . . (2.1) . . . (2.1) where where =
= the athe anglngle bete betweeween the dn the direirectiction of on of the lothe loadad and the direction of the grain.
and the direction of the grain. 2.3.4 Modulus of elasticity and rigidity.
2.3.4 Modulus of elasticity and rigidity. Design valuesDesign values of
of the the modmoduluulus s of of elaelastisticitcity y and rigidiand rigidity ty are given inare given in Table 2.3.
Table 2.3. NOT
NOTE: E: It shoulIt should d be be notnoted ed thathat t the modulthe modulus us of of elaelastisticitcity, for y, for thethe vari
various stresous stress s gragrades des givgiven en in in TabTable le 2.32.3, , referefers rs to to the averagthe averagee modulus of elasticity for the stress-graded timbers that are grouped modulus of elasticity for the stress-graded timbers that are grouped togethe
together within a r within a stresstress grade. s grade. TherefTherefore, when a ore, when a bettebetter estimate forr estimate for deflection is required, the modulus of elasticity values derived solely deflection is required, the modulus of elasticity values derived solely fr
from om TaTablble e 2.2.3. 3. fofor r a a gigiveven n ststreress ss grgradade e shshouould ld eieithther er bebe conserv
conservativelatively y modifiemodified d or or accuraaccurate values te values should be should be obtainobtained fromed from in-grade verification.
in-grade verification. 2.3
2.3.5 .5 BasBasic ic worworkinking g strstressesses es in in tentensiosion n (so(softwftwoodoodss only).
only). The The basbasic ic worworkinking g strstressesses es in in tentensiosion, for n, for thethe
va
variorious us F-gF-graradedes s gigiveven n in in TaTablble e 2.2.3 3 fofor r sosoftwftwoooodd timbers, shall be multiplied by the factor 0.85.
timbers, shall be multiplied by the factor 0.85. 2.4 DESIGN.
2.4 DESIGN. 2.4.1
2.4.1 PermPermissibissible le stresstresses.ses. PerPermismissibsible le strstressesses es forfor sstrtrucuctuturaral l titimbmberer, , whwhetetheher r ssawawn n or or lalamiminanatetedd co
consnstrtrucuctiotion, n, or or in in popole le forform, m, shshalall l be be obobtatainined ed byby mu
multltipiplylyining g ththe e babasisic c woworkrkining g ststreresssses es gigiveven n inin Clause 2.3 by modification factors such as those given in Clause 2.3 by modification factors such as those given in Clause 2.5 as are appropriate to the service conditions. Clause 2.5 as are appropriate to the service conditions. For
For exampexample,le, F F bb the the perpermismissibsible le strstress ess in in benbendinding g isis given by — given by — F F b b == . . . . . . (2(2.2.2)) where where k
k = = the prthe produoduct of the rct of the releelevanvant modit modificficatiationsons factors, such as those in Clause 2.5, as are factors, such as those in Clause 2.5, as are ap
apprpropopririatate e to to ththe e papartrticiculular ar seservrvicicee condi
conditions for whichtions for which the structuthe structural memberral member is being designed.
is being designed. NOTES:
NOTES: 1.
1. As an examAs an exampleple, the fact, the factoror k k for the design bending stress of afor the design bending stress of a solid timber beam is typically given by
solid timber beam is typically given by k k == k k 11k k 22k k 88k k 1111k k 1212..
2.
2. For For convconvenienienceence, , the the modmodifiificatcation ion facfactortors s are are colcollatlated ed andand referenced in Appendix I.
referenced in Appendix I. 2.4.2 Deflections.
2.4.2 Deflections. Deflection calculations shall take intoDeflection calculations shall take into account the modification factors in Clause 2.5.1.2. account the modification factors in Clause 2.5.1.2. 2.5 MODIFICATION FACTORS.
2.5 MODIFICATION FACTORS. 2.5.1 Duration of load.
2.5.1 Duration of load. 2.5.1.1
2.5.1.1Effect on strength.Effect on strength. In order to derive permissibleIn order to derive permissible de
desisign gn ststreresssseses, , ththe e babasisic c woworkrkining g ststreress ss shshalall l bebe multiplied by the appropriate duration of load factor multiplied by the appropriate duration of load factor k k 11
fr
from om TaTablble e 2.2.5. 5. ThThis is fafactctor or is is shshowown n grgrapaphihicacalllly y inin Figure 2.1.
Figure 2.1.
In checking the strength of a structural element, all load In checking the strength of a structural element, all load combinations must be considered.
combinations must be considered.
For any given combination of loads of differing duration, For any given combination of loads of differing duration, the factor
the factor k k 11 to be used is that appropriate to the loadto be used is that appropriate to the load wh
whicich h is is of of ththe e shshorortetest st duduraratitionon. . In In TaTablble e 2.2.5, 5, ththee effective duration of a peak load refers to the cumulative effective duration of a peak load refers to the cumulative duration for which the peak load occurs.
duration for which the peak load occurs. For
For the purpothe purposes of ses of intinterperpretretatiation on in in the the selselectection of ion of load-duration factors in this Standard, the following shall load-duration factors in this Standard, the following shall apply:
apply: (a)
(a) DeaDead d loaloads, and live ds, and live loaloads which are removds which are removed ored or replaced at regular intervals such that the structure replaced at regular intervals such that the structure remains fully loaded for a substantial proportion of remains fully loaded for a substantial proportion of its life, are to be considered ‘permanent loads’. its life, are to be considered ‘permanent loads’. (b)
(b) Live loads (sucLive loads (such as those due to vehiclh as those due to vehicles or people)es or people) that act on floors, and are applied at frequent but that act on floors, and are applied at frequent but irregular intervals such
irregular intervals such that the structurethat the structure is unloaded,is unloaded, or loaded well below the allowable maximum, for or loaded well below the allowable maximum, for most of each day, are to be considered ‘loads of five most of each day, are to be considered ‘loads of five months duration’.
months duration’. (c)
(c) Live loadsLive loads, such as tho, such as those arising durse arising during erecting erection andion and ma
mainintetenanancnce, e, anand d at at ininfrfreqequeuent nt crcrowowd d loloadadining,g, applied for periods of a few days and at infrequent applied for periods of a few days and at infrequent int
intervervalsals, , are to are to be be conconsidsidereered d ‘lo‘loads of ads of fivfive e daydayss duration’.
duration’. (d
(d) ) GuGust st wiwind nd loloadads s wiwith th a a lolong ng reretuturn rn peperioriod, d, susuchch asthose referred to in AS 1170.2, and impact loads asthose referred to in AS 1170.2, and impact loads suc
such h as as thothose causese caused d by by falfallinling g weiweightghts s or or snasnatchtch li
liftfts, s, arare e to to be be coconsnsididerered ed ‘l‘loaoads ds of of fifive ve sesecocondnd duration’.
duration’. COPYRIGHT