AS NZS 1664 2 Supp 1-1997 Aluminium structures - Allowable stress design - Commentary (Supplement to AS NZS 1664 2 1997)《铝结构 安全允许应力设计 注释（AS NZS 1664 2 1997的补充）》.pdf

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1、AS/NZS 1664.2 Supp1:1997AS/NZS 1664.2Supplement 1:1997Aluminium structuresPart 2: Allowable stress designCommentary(Supplement 1 toAS/NZS 1664.2:1997)Accessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 2006AS/NZS 1664.2 Supp1:1997This Joint Australian/New Zealand Standard was pre

2、pared by Joint TechnicalCommittee BD/50, Aluminium Structures. It was approved on behalf of the Councilof Standards Australia on 27 June 1997 and on behalf of the Council of StandardsNew Zealand on 11 July 1997. It was published on 5 September 1997.The following interests are represented on Committe

3、e BD/50:The Association of Consulting Engineers, AustraliaAluminium Development CouncilAustralian Building Codes BoardInstitution of Professional Engineers New ZealandUniversity of SydneyReview of Standards. To keep abreast of progress in industry, Joint Australian/New Zealand Standards are subject

4、to periodic review and are kept up to date by the issueof amendments or new editions as necessary. It is important therefore that Standards usersensure that they are in possession of the latest edition, and any amendments thereto.Full details of all Joint Standards and related publications will be f

5、ound in the StandardsAustralia and Standards New Zealand Catalogue of Publications; this information issupplemented each month by the magazines The Australian Standard and StandardsNew Zealand, which subscribing members receive, and which give details of newpublications, new editions and amendments,

6、 and of withdrawn Standards.Suggestions for improvements to Joint Standards, addressed to the head office of eitherStandards Australia or Standards New Zealand, are welcomed. Notification of anyinaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should be madewithout delay in or

7、der that the matter may be investigated and appropriate action taken.Accessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 2006AS/NZS 1664.2 Supp1:1997AS/NZS 1664.2Supplement 1:1997Aluminium structuresPart 2: Allowable stress designCommentary(Supplement 1 toAS/NZS 1664.2:1997)Origi

8、nated in Australia as part of AS 1664 1975.Previous Australian edition AS 1664 1979.Jointly revised and designated AS/NZS 1664.2 Supplement 1:1997.Incorporating:Amdt 11999PUBLISHED JOINTLY BY:STANDARDS AUSTRALIA1 The Crescent,Homebush NSW 2140 AustraliaSTANDARDS NEW ZEALANDLevel 10, Radio New Zealan

9、d House,155 The Terrace,Wellington 6001 New ZealandISBN 0 7337 1285 1Accessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 2006AS/NZS 1664.2 Supp1:1997 2PREFACEThis Commentary was prepared by the Standards Australia/Standards New ZealandCommittee BD/50, Aluminium Structures. It is

10、intended to be read in conjunction withAS/NZS 1664.2, Aluminium Structures, Part 2: Allowable stress design, but it does notform an integral part of that Standard.The objective of this Commentary is to provide background material to the requirementsof AS/NZS 1664.2.The clause numbers and titles used

11、 in this Commentary are the same as those inAS/NZS 1664.2 except that they are prefixed by the letter C.Gaps in the numerical sequence of this Commentarys clause numbering means that noexplanation of or background to the missing clause(s) is necessary. Copyright STANDARDS AUSTRALIA/ STANDARDS NEW ZE

12、ALANDUsers of Standards are reminded that copyright subsists in all Standards Australia and Standards New Zealand publications and software.Except where the Copyright Act allows and except where provided for below no publications or software produced byStandards Australia or Standards New Zealand ma

13、y be reproduced, stored in a retrieval system in any form or transmitted by any meanswithout prior permission in writing from Standards Australia or Standards New Zealand. Permission may be conditional on anappropriate royalty payment. Australian requests for permission and information on commercial

14、 software royalties should be directed tothe head office of Standards Australia. New Zealand requests should be directed to Standards New Zealand.Up to 10 percent of the technical content pages of a Standard may be copied for use exclusively in-house by purchasers of theStandard without payment of a

15、 royalty or advice to Standards Australia or Standards New Zealand.Inclusion of copyright material in computer software programs is also permitted without royalty payment provided such programsare used exclusively in-house by the creators of the programs.Care should be taken to ensure that material

16、used is from the current edition of the Standard and that it is updated whenever the Standardis amended or revised. The number and date of the Standard should therefore be clearly identified.The use of material in print form or in computer software programs to be used commercially, with or without p

17、ayment, or in commercialcontracts is subject to the payment of a royalty. This policy may be varied by Standards Australia or Standards New Zealand at any time.Accessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 20063 AS/NZS 1664.2 Supp1:1997CONTENTSPageSECTION C1 GENERALC1.1 SCO

18、PE . 4C1.2 MATERIALS . 4C1.3 SAFETY FACTORS 4C1.4 REFERENCED DOCUMENTS 4SECTION C2 DESIGN PROCEDUREC2.2 PROCEDURE 5C2.3 LOADING . 5SECTION C3 GENERAL DESIGN RULESC3.4 ALLOWABLE STRESSES . 6SECTION C4 SPECIAL DESIGN RULESC4.1 COMBINED COMPRESSION AND BENDING 14C4.2 TORSION AND SHEAR IN TUBES 14C4.4 C

19、OMBINED SHEAR, COMPRESSION AND BENDING 14C4.5 HORIZONTAL STIFFENERS FOR WEBS 14C4.6 VERTICAL STIFFENERS FOR SHEAR WEBS 14C4.7 EFFECTS OF LOCAL BUCKLING ON MEMBER PERFORMANCE . 15C4.8 FATIGUE . 18C4.9 COMPRESSION IN SINGLE WEB BEAMS AND BEAMS HAVINGSECTIONS CONTAINING TUBULAR PORTIONS . 19C4.10 COMPR

20、ESSION IN ELASTICALLY SUPPORTED FLANGES . 23SECTION C5 MECHANICAL CONNECTIONSC5.1 BOLTED AND RIVETTED CONNECTIONS 24C5.2 METAL STITCHING STAPLES . 25C5.3 SELF TAPPING SCREW CONNECTIONS 25SECTION C6 FABRICATIONC6.6 PAINTING 27SECTION C7 WELDED CONSTRUCTIONC7.1 ALLOWABLE STRESSES FOR WELDED MEMBERS .

21、28C7.2 FILLER WIRE 29C7.3 MEMBERS WITH LONGITUDINAL WELDS . 29C7.4 MEMBERS WITH TRANSVERSE WELDS . 29SECTION C8 TESTINGC8.2 TEST REQUIREMENTS 30C8.4 PROCEDURE 30Accessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 2006AS/NZS 1664.2 Supp1:1997 4STANDARDS AUSTRALIA/STANDARDS NEW ZEA

22、LANDAustralian/New Zealand StandardAluminium structuresPart 2: Allowable stress designCommentarySECTION C1 GENERALC1.1 SCOPE These specifications apply to normal ambient temperature uses ofaluminium alloys. For higher temperatures, strengths and other properties (such ascorrosion resistance) of diff

23、erent alloys are affected to varying degrees. For informationregarding properties at elevated temperatures, the supplier should be consulted.C1.2 MATERIALS The alloys covered in the specifications are those that arenormally used for general structural purposes. Most are covered by applicableAustrali

24、an/New Zealand specifications. Additional information on these alloys, the temperdesignations, and the products available is published in Reference 1.C1.3 SAFETY FACTORS The specifications for aluminium structures inReference 19 are not limited as to type of structure. The general formulas in Table

25、3.4(C)can be applied to any structure, with appropriate values substituted for the factors ofsafety nyand nu. The values of factors of safety are given in Table 3.4(A) for Buildingtype structures and for Bridge structures. Building type structures include highwaysigns, luminaires and traffic signals

26、. The Bridge structures cover bridges that are notdesigned according to Reference 2.C1.4 REFERENCED DOCUMENTS The Standards listed in Clause 1.4 are subject torevision from time to time. A check should be made with Standards Australia or StandardsNew Zealand, as appropriate, as to the currency of an

27、y document referenced in the text.COPYRIGHTAccessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 20065 AS/NZS 1664.2 Supp1:1997SECTION C2 DESIGN PROCEDUREC2.2 PROCEDURE Calculated stresses in the members resulting from externalloading are compared with the appropriate allowable str

28、esses. Alternatively, the provisionsof Section 8, Testing, can be used.C2.3 LOADING AS/NZS 1664.2 permits the use of reduced wind or seismic loads orcombined loads involving wind or seismic loads. This reduction is only applicable inAustralia because for New Zealand NZS 4203:1984 already allows for

29、such a reduction.COPYRIGHTAccessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 2006AS/NZS 1664.2 Supp1:1997 6SECTION C3 GENERAL DESIGN RULESC3.4 ALLOWABLE STRESSESC3.4.2 Tension, axial, net section In general, the allowable tensile stress for buildingstructures is the lower of two

30、 values that results from applying a factor of safety of 1.65to the yield strength or 1.95 to the tensile strength. The corresponding factors of safetyused to determine allowable tensile stresses for bridge structures are 1.85 and 2.2. Thesefactors of safety are the same as those that were used in R

31、eferences 4 and 5.In the general formula for determining allowable tensile stress on the basis of the ultimatetensile strength, the factor of safety nuis multiplied by a factor kt. For regions farther than25 mm from a weld, this factor is 1.0 for all the alloys that appear in the specifications,exce

32、pt for alloy 2014-T6. The value of ktfor 2014-T6 is 1.25. This factor is introduced totake account of the fact that this high-strength alloy is somewhat more notch sensitivethan the other alloys listed in the specifications. The resulting allowable tensile stress forbridge structures of 2014-T6 is t

33、he same as that used in specifications for structures ofthis alloy published in Reference 6.C3.4.3 Tension in extreme fibres of beamsstructural shapes bent about strongaxis, rectangular tubes This allowable tensile stress is the same as that specified foraxial tension. This Clause is intended to app

34、ly to a wide variety of shapes, includingtrapezoidal corrugated sheet. As a result, no attempt is made to take advantage of theshape factor which would apply to standard structural shapes and which justifiessomewhat higher allowable tensile stresses.C3.4.4 Tension in extreme fibres of beamsround or

35、oval tubes The allowabletensile stresses for round or oval tubes subjected to bending are somewhat higher than forstructural shapes. Analysis and tests (Ref. 7) have demonstrated that yielding or failure oftubular beams does not occur until the bending moment considerably exceeds the yieldmoment pre

36、dicted by the ordinary flexure formula. This results from the non-lineardistribution of stress in the inelastic range. Yielding does not become apparent as soon asthe calculated stress in the extreme fibre reaches the yield strength because the less highlystressed fibres near the centre of the beam

37、are still in the elastic range. The constants 1.17and 1.24 can be considered as shape factors for yielding and ultimate strength,respectively.These constants were picked from curves of yield strengths at 0.2 percent offset for tubesof representative proportions. The shape factors on ultimate strengt

38、h were deduced fromapparent and actual stress-strain curves at a stress corresponding to tensile strength of thematerial.C3.4.5 Tension in extreme fibres of beamsshapes bent about weak axis,rectangular bars, solid round bars and plates As in the case of round tubes, theoryand tests have shown that a

39、luminium alloy members of these shapes can undergo bendingmoments that are considerably higher than those predicted on the basis of the ordinaryflexure formula (Ref. 8). In this case, the shape factors used for yielding and ultimatestrength, respectively, are 1.30 and 1.42. That these factors are co

40、nservative can be notedfrom the fact that the shape factor for fully plastic action is 1.50 for a rectangular section.C3.4.6 Bearing on rivets and bolts Bearing yield and ultimate strengths are definedby means of a test on a pin in a hole, as described in ASTM E238 (Ref. 9). The bearingyield stress

41、is the stress at an offset of 2 percent of the hole diameter on a bearing stress-deformation curve. The ratio of edge distance to fastener diameter in this test is normally2.0, where edge distance is the distance measured from the centre of the hole to the edgeof the material in the direction of app

42、lied stress. Bearing tests (Ref. 10) show that forratios of edge distance to fastener diameter as small as 1:5, it is conservative to reduce theallowable bearing stress by the ratio of the edge distance to twice the fastener diameter.The specifications do not allow ratios of edge distance to fastene

43、r diameter smaller than1:5.COPYRIGHTAccessed by ISONET - CHINA STATE BUREAU OF TECHNICAL SUPERVIS on 06 Jun 20067 AS/NZS 1664.2 Supp1:1997Tests (Ref. 11) have demonstrated that a relatively even distribution of load among thefasteners is achieved before ultimate failure of mechanically fastened join

44、ts in structuralaluminium alloys. Nevertheless, the factor of safety normally applied to ultimate strengthis increased by 20 percent since this safety can normally be obtained with relatively littlecost.C3.4.7 Bearing on flat surfaces and pins and on bolts in slotted holes The bearingstrength for fl

45、at surfaces, elements with pins in holes and elements with pins or bolts inelongated holes is 2/3 the bearing strength of elements joined by properly fitting rivetsand bolts. This requirement originally was adopted from steel specifications. A lowerbearing strength appears to be reasonable in these

46、cases because the applied pressure canbe much more concentrated than that in riveted or bolted joints, because the diameter ofthe loading element (pin) can be small compared to the diameter of the opening in theelement that is being loaded. Good practice in bolted and riveted joints requires areason

47、able fit between fastener and hole diameter.C3.4.8 Compression in columns, axial, gross sectionC3.4.8.1 General The formulas in this Clause for values of kL/r exceeding S1approximate the column strength given by the tangent modulus column formula. Thetangent modulus formula is. . . C3.4.8.1(1)whereF

48、cr= column strengthEt= tangent modulus (slope of stress strain curve) corresponding to FcrkL = effective length of columnr = least radius of gyration of columnIn the elastic range, this formula is simply the Euler column formula, which is used as abasis for allowable stresses for values of kL/r exce

49、eding S2. For values of kL/r between S1and S2the tangent modulus formula is approximately closely by the straight line (Ref. 8),which is used as a basis for the allowable stress formula.Numerous tests have shown that these formulas closely predict the strength of essentiallystraight columns (Refs. 8 and 12). To ensure adequate safety in the presence of accidentaleccentricity and initial crookedness, which may reduce the strength of practical columns(Refs. 13 and 14), the factor of safety nurather than nyis applied to column strength.The effective length of columns is no