SANS 10120-3 H-1990 Code of practice for use with standardized specifications for civil engineering construction and contract documents Part 3 Guidance for design Section H Structu.pdf

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 H-1990 Structural steelwork PART 3 : GUIDANCE FOR DESIGN SECTION H CONTENTS Clause PRE-TENDER CONSIDERATIONS Investigations .

4、General Cost . Administration . Selection of design codes Details to be given on drawings Type of contract . Data for tendering purposes Hard-standings . Documentation Drawings . Compi l ing tenderlcontract document for structural steelwork Corrosion protection . Dressing edges of flame-cut plates .

5、 Tolerances . Tests DESIGN REQUIREMENTS General Materials Weather-resistant steel . Brittle fracture Welding of special steels Steel of unknown properties Loading Dead and imposed loads . Wind loads . Loads due to temperature changes . . F1 uctuations of stress (fatigue) Holes for Holding-down Bolts

6、 . Joints in Compression Lifting Devices for Erection and Maintenance . Welding Techniques . General Guidance on weldability and methods Butt welds . Protective Treatment . General Safety During Erection . Sundry Items . Handrails Open grid floors . Floorplate floors APPLICABILITY OF OTHER CODES . T

7、EST PROCEDURES Normal Tests . Destructive Tests Tensioning of Steel Tape for Measurement of Tolerances . QUALITY CONTROL AND OTHER CONSIDERATIONS . General Lessons from Design Failures . General . Failure of the West Gate Bridge Page Number TEXT REFERENCES . 6 Second Revision August 1990 This sectio

8、n of the code supersedes SABS 0120 : Part 3 : Section H-1983 Approved by the COUNCIL OF THE SOUTH AFRICAN BUREAU OF STANDARDS SABS 0120 : Part 3 Section H-1990 Structural steelwork SABS 1200 H : STRUCTURAL STEELWORK NOTE: The clause number(s) given at the beginning or after the heading of a clause i

9、slare, unless otherwise stated, the number(s) of the relevant clause(s) of SABS 1200 H. PRE-TENDER CONSIDERATIONS INVESTIGATIONS General. In addition to investigating founding conditions, investigate the dimen- sionl requirements for the structure(s), and the loads to be carried (see 2.3) by the str

10、ucture(s). Cost The cost of completed structural steelwork depends on the amount of work (man-hours plus plantlequipment-hours) required per unit of mass, in addition to the cost of the steel itself and the cost of the corr sion protection system chosen (for corro- sion protection details see SABS 1

11、200 HC13). The completed cost per unit of mass of heavy steelwork involving a minimum of work will be less than that of light steelwork involving long lengths of light sections and still less than that of steelwork involving short lengths of light steelwork with many joints. ADMINISTRATION Selection

12、 of Desi n Codes. Ensure that structural steelw rk to be executed in terms of SABS 1200 H isgdesigned in accordance with SABS 016223 and this part of the code. Details to be Given onJyzint. Ensure that drawings for steelwork referred to in Im-ml the requiremen% of Subclause 5.1.l.of SABS 1200 H and

13、give sufficient detail for the schedule to be drawn up as shown in the typical schedule of Section H of Part 4 of the code. T e of Contract. Decide whether the documentation is to provide for the structural -P S eelwork to be executed a) as part of a main civil contract; b as part of an architectura

14、l contract; C as a separate contract; or d) as a nominated subcontract to the contract referred to in either (a) or (b) above. Data for Te derin Pur oses. Where the data called for in Subclause 2.1 of SZEfio?i-df-ofhe code have not been provided in the tender document or on the drawings, ensure that

15、 the information is issued before the closing date for receipt of tenders so that all tenders may be evaluated on the same basis and the need for subsequent negotiation is avoided. Hard-standin s (Subclause 5.5). Where SABS 1200 H i S used for a nominated sub- - confifrEw beeciwith SABS 1200 nfF or

16、SABS 1200 AA f 1, with any other general specifAcation, and with any other civil or mechanical engineering or architects general con- ditions of contract (such as those of Spoornet (E5), the Public Works Department (PW 54), and the A reement and schedule of conditions of building_contract as recomme

17、nded by thh-%T-iFoh Af rl can Arcliit%6TtfFi$Ssocii-01: South African Quantity Surveyors, and the Building Industries Federation (South Africa) provided that the contract includes a) special conditions of contract, or b) in the project specification, clauses that comply with the requirements of 1.3.

18、2.2 and 1.3.2.3. Contract erice adustmeg. Where SABS 1200 AH) is omitted from the contrac;, tkiT-ln .fddj- specification the contents of Su lause 8.2.2 of SABS 1200 AH37. (S ee also Subclause 1.2.1 of Section AH $5 , and Subclause l.L(b) of Section AH) of Part 2 of the code.) roved laboratories. Unl

19、ess otherwise stated in the project specification, tests or dKsiiiiwofIlirequ7-Fed in terms of a specification may be carried out in the testing laboratories of the South African Bureau of Standards, the Council for Scientific and Industrial Research, the relevant government departments or local aut

20、horities, or by other recognized or approved laboratories or inspection authori - ties. Definitions. Where GCC are not included in the contract, ensure that suitable defi- iiifiloiiS-of the following are included: a Employer b Engineer c Contractor site Prel imi nary and genes!-!terns not scheduled.

21、 When the engineer requires that the - conEact6FTTEeT“For sunin7 etc., should cover all costs of a pre- liminary and general nature in addition to the applicable of the operations spe- cified in Subclauses 8.3.1-8.3.11 of SABS 1200 H, include in the project specifi- cation the following: a) If SABS

22、12003) is included in the contract, requirement to theeffect that 7 the rovi sions of Subclause 8.3.1 of SABS 1200 AH amlv to each af Subclauses - 8.3.i-8.3.11, as r levant, of SABS 00 H, or S 51 b) if SABS 1200 A47 or SABS 120 AA is included in the contract, the contents of Subcl ause 8.3.1 of SABS

23、 1200 AH ), suitably amended with regard to the clause - refsrences. Corrosion Protect*. Refer to SABS 1200 HC) and Section HC of the code. Dressi n Edges of F1 ame-cut Pi ates (Subcl ause 5.2.3). Note that f l ame-cutti ng i S - accept% normardure and that where f l ame-cutt ng i S not to be a1 low

24、ed, this must be stated in the project specification. (See also Subclause 2.l(b) of Section H of Part 2 and Subclause 3.2.2.2 of Section H of Part 5 of the coce.) To1 erances - Tolerances - for extensions to existin structure (Subclause 6.2). Where the project nvolves extensions %?K3xTig-hncIude in

25、the project specif tcation a clause that enabl es the contractor to obtain the engineer S agreement to varying the tolerance reauirements where necessitated by errors in the existing structure. SABS 0120 : Part 3 Section H-1990 Structural steelwork Tension on steel ta e (Subclause 6.1.1). Where the

26、tolerances applicable to a 3FUcTuKare h-Ri at the tape must be tensioned to the standard rating given on the tape, include in the project specification a clause based on Subclause 3.2.6.1 of Section H of Part 5 of the code. To1 erances for gantry crane rail S (Subclause 6.2). Excessive mi sal ignmen

27、t i S a ma or cause of rail wear and high lateral forces on gantries. Some authorities reiard the to1 erances specifled in Subclause 6.2 of SABS 1200 H as sul tab1 e on1 y for run-of-the-mill buildings and consider that the cost of greater accuracy is justifiable for gantries where satisfactory cran

28、e performance is required under heavy and constant traffic conditions and, in particular, for gantries spanning more than 15 m . Tests Radio ra hic tests (Subclause 7.3). The cost to the contractor of radiographic es ing on lTG3Te of the work is made up of the cost of ffee a) hiring the equipment wi

29、th qualified technicians and moving it to and from the site; b) film and its processing; and c) standby time while decisions are awaited whether repairs and retesting are to be carried out or not. The i tems referred to in (a) and (c) above are independent of the length of we1 ds to be subjected to

30、radiographic testing, whereas those in (b) are dependent solely on the length of weld. Where such tests are to be scheduled, provide items for each of (a), (b) and (c) above and state the total length of joints that may have to be tested and a reason- able forecast of the standby time. Mechanical te

31、sting of welds (Subclause 7.3). For the mechanical testing of welds, ca or he tests given Tn the applicable project welding specification, such as AWi1D:.j6t. Avoid the use of welding tests given in speclflcations such as BS 5500 1, as such tests apply to pressure vessels and not to tanks for storin

32、g liquids at near atmospheric pressures. The mechanical tests laid down in BS 55007) are expensive and should not be applied except where the stresses or pressures i nvol ved make them necessary. Bear in mind the fact that should the welds be found to be sound, the employer will be required to meet

33、the costs of such tests. Furthermore, if tests that are more sophisticated than necessary are specified, the contractor may have a valld claim for delay to his work program or for an extension of time. Naturally, should the welds be found to be defective, all costs will be for the contractors accoun

34、t. (See also Subclause 3.2.6 of Section H of Part 5 of the code.) DESIGN REQUIREMENTS GENERAL a Design in accordance with the requirements of SABS 01622). b The design considerations set out in 2.2-2.7 are intended primarily to give guidance as to the matters that may need to be specified or on whic

35、h verification data may be required for design-and-construct contracts and to ensure compliance with thos requirements of BS 51358) that do not conflict with SABS 1200 H or S SABS 0162 1. c) See 5.2.2. MATERIALS Weather-resistant Steel (Subclause 3.1). Weather-resistant steel having a minimum yWfiFe

36、357T3?53E and a minimum tensile st ength of 480 MPa may be regarded r as complying with the requirements of SABS 14319 Grade 350WC. Bri ttl e Fracture (Subcl ause 3.1) When deciding whether or not to grant approval for the use of steels other than those specified in Subclause 3.1 of SABS 1200 H, con

37、sider the requirements of SABS 01622) and note that, for welded elements subject to tensile stresses, steels excluded in term of Subclauses 3.1.l(a)-(c) of SABS 1200 H may be used provided that they comply with Subclause 3.1.l(c) of that specification. Where welded structures are to be exposed to lo

38、w temperatures and especially if dynamic loads may be applied when the structure is at a low temperature, take spe- cial care to prevent the occurrence of brittle fracture. SABS 0120 : Part 3 Section H-1990 Structural steelwork 2.2.2.3 Information on brittle fracture and its avoidance is obtainable

39、from technical pub1 icationslo). 2.2.3 Welding of Special Steels (Subclause 3.2). Where welding of special steel is to be done, ascertain the weldability of the steel. 2.2.4 Steel of -. Unknown Properties (Subclause 3.3) 2.2.4.1 Be cautious in the choice of design stresses when angle sections having

40、 arms of length 90 mm and less, cold-formed sections and hollow sections are being used, as these may have been manufactured by a wide variety of manufacturers. The material properties of these sections depend on the source manufacturer and must therefore be verified, since the sections may have bee

41、n manufactured from steel that d es not comply with the applicable requirements of SABS 14319) or SABS 657: Part 1113 Their physical properties cannot be guaranteed and the actual factor of safet; may differ from the theoretical factor of safety. The steel industry is reluctant to state a minimum yi

42、eld stress for such steel but in South Africa a yield stress of 225 MPa may generally be assumed. (See Subclause 3.2.1.2 of Section H of Part 5 of the code. ) 2.2.4.2 Whilst the following items are available in SABS 14319) grade steels, they ai-e usual l y manufactured from commerci a1 qual i ty ste

43、el (such tee1 general l y doe:$ not have a guaranteed minimum yield strength) (see SABS 01622f): a) Angle sections having arms of length 90 mm or less; b cold-formed sections such as Z, top-hat and lipped channels; C egg-crate flooring, ladders, etc. ; d) rounds of diameter less than 45 mm; e) flats

44、 of width less than 180 mm. 2.2.4.3 Welding quality steel (a low carbon steel that is generally used for structural hollow sections and tubes) also has no guaranteed yield strength. LOADING Dead and Im osed Loads. Apply a1 l dead and osed loads strictly in accordarice 18 iikirements of SABS 0160 . S

45、tate crane loads, surge loads and other special loads. Although snow loads may not occur, do not reduce imposed roof loads. Wind Loads. Refer to Chapter V: Part 2 of CP 313)* and SABS 016012) for the selec- tion of factors for topography, basic wind velocity and ground roughness for each design. NOT

46、E: Data are obtainable from the Weather Bureau for the determination of the basic wind velocity for a particular site. Loads Due to Tem era.$-re Chanae?. Where loads due to temperature changes have to be SkmEo 55iuicaa-E such loads using a temperature variation of 17 C above and below the mean tempe

47、rature for internal steelwork and a range of -12 “C to +43 “C for exterior unprotected steelwork. F1 uctuations of Stress ratiw. Design, in accordance with the requirements of SABS, for probab exress fluctuations. HOLES FOR HOLDING-DOWN BOLTS (Subclause 5.2.4 - see also SABS 016114). State, on the d

48、esign drawings, the diameters of holes for holding-down bolts (see Tab1 e 1). SABS 0120 : Part 3 Section H-1990 Structural steelwork TABLE 1 - HOLES FOR HOLDING-DOWN BOLTS 1 Boltsize I Hole diameter* (theoretical ) , mm *a) Smaller holes are permissible where holding-down bolts are grouted into Up t

49、o M24 M30 to M48 M56 and larger pockets. b) For bolt sizes in excess of M24, round bar diameters and thread diameters do not coincide, e.g. an M56 bolt has a 60 mm diameter shank, and the hole diameter required is (60+25) mm . Bolt diameter +l0 Bolt diameter +l5 Bolt diameter t25 JOINTS IN COMPRESSION (Subclause 5.2.5). Each joint that is required to transfer a load in bearing should, after being aligned correctly on both axes, have at least 75 % of each section area in contact located mainly in the flanges. LIFTING DEVICES FOR ERE