SANS 10120-3 HE-1983 Code of practice for use with standardized specifications for civil engineering construction and contract documents Part 3 Guidance for design Section HE Struc.pdf

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1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. SABS 0120 : Part 3 Section HE-1983 Structural aluminiumwork PART 3 : GUIDANCE FOR DESIGN SECTION HE CONTENTS Clause PRE-TENDER CONSIDERATIONS . Investiga

4、tions Administration . Documentation Structural quality aluminium Principal alloys . Surface treatment prevention of corrosion at interfaces with other materials Drawings DESIGN REQUIREMENTS . General . . Selection of alloys Aluminium aloy groups . Reduction of strength when welded . Avoidance of “s

5、econdary“ alloys . Choosing a SuLtable Aluminium Section . Selecting from sections and dies in stock . Design of a new section . Design of the Structure Loads . . Design for aluminium. not steel APPLICABILITY OF OTHER CODES . TEST PROCEDURES QUALITY CONTROL AND OTHER CONSIDERATIONS Page Number Novem

6、ber 1983 Approved by the COUNCIL OF THE SOUTH AFRICAN BUREAU OF STANDARDS SABS 0120 : Part 3 Section HE-1983 Structural aluminiumwork SABS 1200 HE : STRUCTURAL ALUMINIUMWORK NOTE: The clause number(s) given at the beginning or after the heading of-a clause is/are, unless otherwise stated, the number

7、ts) of the relevant clause(s) of SABS 1200 HE. PRE-TENDER CONSIDERATIONS INVESTIGATJONS. Ascertain which sections and alloys will be most readily obtainable for the project but, before selecting any section from a catalogue, study 2.2 below and consider the following recommenda- tions : a) If the qu

8、antity is small, ascertain which sections are available from the local distributors or their branches in other centres and select from those sections only. b) If the quantity is moderate and time permits, select sections for which dies are available so that the sections may be produced readily if st

9、ocks are insufficient. C) If the quantity is large and an uncatalogued section is warranted (and provided that there is enough time), design the required profile for the new section (see 2.2.2 below). ADMINISTRATION DOCUMENTATION Sitr Aluminium. Because the physical properties of structural quality

10、aluminium are guaranteed by the supplier, specify this material for all elements that are designed on the basis of the permissible stresses given in CP 11). The contractor can be required to confirm (see Subclause 7.1 of SABS 1200 HE) by means of test certificates (from the supplier or an independen

11、t approved laboratory). that any particular member made of structural quality aluminium does in fact possess the guaranteed physical properties. Principal Alloys (See also 1.3.5 and 2.1.2 below.) Extruded sections. Specify extruded sections of one of the following materials that conform to the requi

12、rements of BS 1414) or SABS llz3), and are available in South Africa: 6082 or 62610. Sheets and plates. Specify sheet and plate sections of one of the following materials that conform to - the requirements of BS 1470) and are available in South Africa: 5083, 5251, or 6082. Alloys not to be specified

13、. Do not design for the use of, or specify, any of the wide range of “secondary“ alloys whose chemical composition and mechanical properties are set out in BS 1470) and BS 1474) but which are not normally available from South African sources. Surface Treatment Structural work a) Do not specify anodi

14、zing of structural members unless abnormal corrosion risks exist or architectural requirements dictate such a finish, as it is an expensive process and untreated aluminium is highly resistant to corrosion. b) On average, a breakdown of the cost of an anodized structure is aluminium material - 33 X,

15、fabrication and erection - 33 X, and anodizing - 33 X. C) In the case of t.he alloys normally used for engineering structures such as masts, towers, and bridges, the members have a mill finish that is sufficintly resistant to atmospheric corrosion to require no protection. d) If structures such as m

16、asts, towers, and bridges require any colour finish, specify a paint finish of white and international orange for masts and towers and red for a structure that constitutes an obstruction. e) Specify thorough cleaning and an etch primer that will ensure that the paint finish will not peel off. Take s

17、pecial care in the selection of paints. Consult the SABS and reputable manufacturers and suppliers of paint for advice and information. Architectural work. Where the maintenance of a particular surface finish or colour is necessary for architectural reasons, a special surface treatment such as anodi

18、zing, spray painting, or enamelling, or provided that the cost of importation or special manufacture is warranted, special alloys that develop a characteristic colour finish in the anodizing process may be specified. Consult the relevant industry for advice and information. Frevention of Corrosion a

19、t Interfaces with Other Materials. Design to avoid direct contact of aluminium with other metals, concrete, soil, and other materials that may attack aluminium. Specify, or show on drawings, a non-metallic non-absorbent insulation or a suitable coating on the aluminium surface or on both surfaces. S

20、chedule such insulation. Drawings (Subclause 3.1). State the alloy designation(s1 on the detail drawings on which the sizes of members are stated (see 1.3.2 above). 1) The structural use of aluminium. 2) Wrought aluminium and aluminium alloys for general engineering purposes - bars, extruded round t

21、ube and sections. 3) Aluminium and aluminium alloys for wrought products. 4) Wrought aluminium and aluminium alloys for general engineering purposes - plate, sheet and strip. SARS 0120 ! Part 3 Section HE-1983 Structural a1umini;lmwork DESIGN REQUIREMENTS GENERAL Selection of hlloys. Consider alumin

22、ium alloys only, because alloys are used, normally, for all types of structures and because an adequate range of alloy compositJons are readily available, NOTE: Aluminium in commercial or chemically pure condition i8 generally used only for el6ctrical plaht and equipment and for various chemical app

23、lications. Select alloys that are corrosion resistant end that have the requjred mechanical properties. lloys that are readily obtainable are 6082 (see BS 1474) and 62610 (see SABS 712) as extrusions, and 5083 (see BS 1470) as plate. Aluminium Alloy Groups Non-heat-treatable (work-hardening) alloys.

24、 Non-heat-treatable alloys are classified as iollows according to the treatment they have received: Condition Treatment (temper) As manufactured. Material which acquirps some temper from shaping processe8s in which there is no special control over thermal treatment or amount of strain harc!enj.ng. 0

25、 Annealed. Material which is fully annealed to obtain the lowest-strength condition. H1 - H8 Strain hardened. Material subjected to the applicatlon of cold work after annealing (or hot forming) or to a combination of cold work and partial annealing/stabilizing in order to secure the specified mechan

26、ical properties. The designations are in ascending order of tensile strength. Beat-treatable alloys. Heat-treatable alloys produced in South Africa are classified as follows according to the treatment they have received: Condition Treatment (teH - Relative tensile -p strenytr properties TB Solution

27、heat-treated and naturally aged. Material which receives low no cold work after solution heat treatment except as may be required to flatten or straighten it. Properties of some alloys in this temper are unstable. TE Cooled from an elevated temperature shaping process and precipitation-treated. medi

28、um TF Solution heat-treated and precipitation-treated. kiigh Reduction of Strength when Welded. Xn the design of load-bearing parts of structures that are to be joined by welding, take account of the fact that heat-treated alloys are weakened by weldiny. Avoidance of “Secondary“ Alloys, Do not desig

29、n for the use of the “secondary“ alloys refrred to in 1.3.2.3 above. CHOOSING A SUITABLE ALUMINIUM SECTION Selecting from Sections and Dies in Stock. Most manufacturers have in stock a wide range of dies and - their catalogues of aluminium sections available list the sections normally held in stock

30、and the dies from which sections that are not held in stock can be extruded. Design of a New Section. The extrusion process permits the designer to develop a section of any shape ,within certain limits, and permits the manufacturer to produce that section, provided on11 that the required quantity ju

31、stifies the cost of a new die. In the design of a new section, take account of the IoLlowing: a) The deflection of aluminium is 3 times that of steel. This flexibility can be counteracted by so placing metal in the section as to increase the moment of inertia. Stability against buckling can be incre

32、ased by strengthening the outer edges of angles, channels, etc., with bulbs or lips. b) Functions which on a steel structure require additional members or extra components can be incorporated in the shape of the aluminium section. c) The shape must be suitable for the extrusion process and must ensu

33、re the even flow of the metal. Sharp corners, sudden variation of thickness, and thin walls must be avoided. The manufacturers of alumunjum sections should be consulted for advice on these aspects. d) The shape of the section must suit the proposed method of fabrication of the structure such as the

34、fitting of bolts, welding, etc, DESIGN OF THE STRUCTURE Loads. Design the structure to carry the loads specified in accordance with the recommendations of SABS 0160) and CP 118). 1) See p.1. 2) Seep.1. 3) See p.1. 4) See p.1. 5) General procedures and loadings to he adopted for the design of buildin

35、gs. SABS 0120 :, Part 3 Section HE-1983 structural aluminiumwork 2.3.2 Design for Aluminium, not Steel. In the design take cognizance of the significant inherent differences hetween aluminium and steel, as set out in Table 1. Develop an arrangement of structural aluminium elements that will carry an

36、d transmit the loads and that takes account of the low modulus of elasticity of aluminium, but makes use of its lightness and of the large variety of profiles available and the consequent flexibility in stress distributj.on over those profiles. Do not create a structure designed for steel but made w

37、ith aluminium members by starting with a traditional or other steel framework and, selecting aluminium sections to carry the stresses. TABLE 1 - COMPARISON OF ALIJMINIUM AND STEEL Typical density Method of producing sections Range of available profiles Typical modulus of elasticity Aluminium 2 700 k

38、g/m 3 0,344 X steel) Extruding Unlimited 70 000 MPa (1/3 x steel) 3 Steel 7,850 kg/m 3 (2,9 X aluminium) Rolling Limited number of standard profiles 210 000 MPa (3 X aluminium) 3. APPLICABILITY OF OTHER CODES 3.1 With the exception of SARS 01605), there are no SARS codes of practice that are applica

39、ble to the design of aluminium structures. 4. TEST PROCELNJRES 4.1 Except where otherwise speciEied, the test procedures recommended in Section H are applicable. 5. QUALITY CONTROL AND OTHER CONSIDERATIONS 5.1 Apply the relevant recommendations of SABS 0157) to the design of structural aluminiumwork. 5) See p.2. 6) Quality management systems. sabs pta