SOUTH AFRICAN NATIONAL STANDARD

Transcription

1 ICS ; ISBN SANS 2001-CS1:2005 SOUTH AFRICAN NATIONAL STANDARD Construction works Part CS1: Structural steelwork

2 Table of changes Change No. Date Scope Abstract Establishes construction requirements for structural steelwork for buildings and other structures, excluding bridges, offshore structures, mobile equipment (stackers, reclaimers, draglines, cranes, etc.), mine shaft steelwork (buntons and guides) and mining conveyances. Also establishes requirements for materials, drawings, workmanship (general, welding and erection), inspections during manufacture, testing of welders, non-destructive tests of welds and permissible deviations. Keywords erection, fabrication, materials, permissible deviations, structural steelwork, welding, workmanship. Acknowledgement Standards South Africa wishes to acknowledge the input of the Southern African Institute of Steel Construction, and the Joint Structural Division of the South African Institution of Civil Engineering and the Institution of Structural Engineers in the development of this part of SANS Foreword This South African standard was approved by National Committee StanSA TC , Construction standards, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. SANS 2001 consists of a number of parts in various stages of preparation, under the general title Construction works. Annex A forms an integral part of this part of SANS Annex B is for information only. Introduction The different parts of SANS 2001 each address a specific component of construction works. The prime purpose in the production of these standards is to create a set of standards that are generally applicable to construction works, and which can be readily modified to make them applicable to particular works. The SANS 2001 family of standards provides technical descriptions of the standard of materials and workmanship that will be used in the works that are executed or in the performance of the works when completed (or both). These standards do not make reference to the actions of those responsible for executing the works or the parties to a contract, i.e. to the constraints relating to the manner in which contract work is to be performed. Neither do they deal with the commercial arrangements of such contracts. These standards are suitable for use in any "in-house" construction work or in all types of engineering and construction works contracts, for example, design by employer, design and build, develop and construct, construction management or management contracts. Standard requirements pertaining to the manner in which works are constructed can be found in the SANS 1921 family of standards.

3 Construction works Part CS1: Structural steelwork 1 Scope This part of SANS 2001 covers structural steelwork for buildings and other structures, excluding bridges, offshore structures, mobile equipment (stackers, reclaimers, draglines, cranes, etc.), mine shaft steelwork (buntons and guides) and mining conveyances. This part of SANS 2001 does not cover roof and side cladding, or the detailed aspects of sundry items such as handrails, ladders, steel flooring and the like, neither does it cover protection of steelwork against corrosion or fire. NOTE This part of SANS 2001 may, with additional clauses and suitable variations made in the specification data (see annex A), be applied to structural steelwork falling outside the scope of this part of SANS Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of SANS All standards are subject to revision and, since any reference to a standard is deemed to be a reference to the latest edition of that standard, parties to agreements based on this part of SANS 2001 are encouraged to take steps to ensure the use of the most recent editions of the standards indicated below. Information on currently valid national and international standards can be obtained from Standards South Africa. ANSI/AWS A5.1/A5.1M, Specification for carbon steel covered arc-welding electrodes. ANSI/AWS A5.17/A5.17M, Specification for carbon steel electrodes and fluxes for submerged arc welding. ANSI/AWS A5.18/A5.18M, Specification for carbon steel electrodes and rods for gas shielded arc welding. ANSI/AWS A5.20, Specification for carbon steel electrodes for flux cored arc welding. ANSI/AWS D1.1/D1.1M, Structural welding code Steel. ASTM A 6/A 6Mb, Standard specification for general requirements for rolled structural steel bars, plates, shapes, and sheet piling. BS 4-1, Structural steel sections Part 1: Specification for hot-rolled sections. 3

4 DIN , Hot rolled steel channels Part 1: Taper flange steel channels; dimensions, masses and sectional properties. EN 10024, Hot rolled taper flange I sections Tolerances on shape and dimensions. EN , Hot rolled products of structural steels Part 2:Technical delivery conditions for nonalloy structural steels. EN 10034, Structural steel I and H sections Tolerances on shape and dimensions. EN , Structural steel equal and unequal leg angles Part 2: Tolerances on shape and dimensions. EN , Hot finished structural hollow sections of non-alloy and fine grain structural steels Part 1: Technical delivery requirements. EN , Hot finished structural hollow sections of non-alloy and fine grain structural steels Part 2: Tolerances, dimensions and sectional properties. ISO , Preparation of steel substrates before application of paints and related products Visual assessment of surface cleanliness Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings. SANS 657-1, Steel tubes for non-pressure purposes Part 1: Sections for scaffolding, general engineering and structural applications. SANS 1282 (SABS 1282), High-strength bolts, nuts and washers for friction-grip joints. SANS 1431, Weldable structural steels. SANS /ISO , Fasteners Part 4: Tolerances Section 1: Tolerances for fasteners Bolts, screws, studs and nuts Product grades A, B and C. SANS /ISO 898-1, Fasteners Part 5: General requirements and mechanical properties Section 1: Mechanical properties of fasteners made of carbon steel and alloy steel Bolts, screws and studs. SANS /ISO 898-2, Fasteners Part 5: General requirements and mechanical properties Section 2: Nuts with specified proof load values Coarse thread. SANS /ISO 4014, Fasteners Part 7: External drive hexagon bolts and screws Section 1: Hexagon head bolts Product grades A and B. SANS /ISO 4016, Fasteners Part 7: External drive hexagon bolts and screws Section 3: Hexagon head bolts Product grade C. SANS /ISO 4017, Fasteners Part 7: External drive hexagon bolts and screws Section 4: Hexagon head screws Product grades A and B. SANS /ISO 4018, Fasteners Part 7: External drive hexagon bolts and screws Section 5: Hexagon head screws Product grade C. SANS /ISO 4033, Fasteners Part 14: Hexagon nuts Section 2: Hexagon nuts, style 2 Product grades A and B. 4

5 SANS /ISO 4034, Fasteners Part 14: Hexagon nuts Section 3: Hexagon nuts Product grade C. SANS /ISO 7413, Fasteners Part 14: Hexagon nuts Section 9: Hexagon nuts for structural bolting, style 1, hot-dip galvanized (oversize tapped) Product grades A and B Property classes 5, 6 and 8. SANS /ISO 7417, Fasteners Part 14: Hexagon nuts Section 11: Hexagon nuts for structural bolting Style 2, hot-dip galvanized (oversize tapped) Product grade A Property class 9. SANS /ISO 7089, Fasteners Part 16: Washers Section 2: Plain washers Normal series Product grade A. SANS /ISO 7090, Fasteners Part 16: Washers Section 3: Plain washers, chamfered Normal series Product grade A. SANS /ISO 7415, Fasteners Part 16: Washers Section 8: Plain washers for highstrength structural bolting, hardened and tempered. SANS (SABS 094), The use of high-strength friction-grip bolts. SANS (SABS 0143), Building drawing practice. SANS (SABS ), The structural use of steel Part 1: Limit-states design of hot-rolled steelwork. SANS (SABS ), The structural use of steel Part 2: Limit-states design of coldformed steelwork. SANS 10403, Formatting and compilation of construction procurement documents. SANS 14713/ISO (SABS ISO 14713), Protection against corrosion of iron and steel in structures Zinc and aluminium coatings Guidelines. 3 Definitions and abbreviation For the purposes of this part of SANS 2001, the following definitions and abbreviation apply: 3.1 Definitions connection bolt, weld, cleat, plate and fitting required to provide an adequate load path between a member and the component to which it connects design drawing fully dimensioned drawing or its electronic equivalent which details the size, material grades and special connections of all the members deviation difference between the actual (i.e. measured) dimension or position and the specified dimension or position 5

6 3.1.4 erection mark drawing drawing or its electronic equivalent that shows erection marks, orientation and, where applicable, the erection method and sequence and details of any temporary steelwork fabrication drawing drawing or its electronic equivalent that shows all the necessary information and detail required to fabricate the structural steelwork fitting plate, flat or rolled section that forms a cleat, gusset or similar part to facilitate the connection or stiffening of structural steel components holding-down bolt/interface drawing drawing that indicates the location of holding-down bolts or details of connections or the interface between the steelwork (or any combination of these) and elements or structures made of other materials ordinary bolt bolt used in a non-preloaded bolt assembly permissible deviation specified limit(s) of deviation within which a dimension or position lies production test plate plate used for testing purposes, and which is made of the same material and using the same procedures as the joint in a component specification data data, provisions and variations that make this part of SANS 2001 applicable to a particular contract or works (see annex A) 3.2 Abbreviation HSFG high-strength friction grip 4 Requirements 4.1 Materials Structural steel Steel used in the fabrication of structural steelwork shall comply with the requirements of SANS 1431 or EN unless otherwise specified in the specification data (see annex A) or in the design drawings. The dimensions and permissible deviations of all steel profiles shall comply with the requirements of the standards listed in table 1. 6

7 Table 1 Standards governing dimensional and permissible deviations 1 2 Profile Applicable standard Angles EN Hollow sections cold-formed SANS Hollow sections hot-formed EN I, IPE and H sections EN Imperial channels BS 4-1 Metric channels DIN Plates, flats and bars ASTM A 6/A 6Mb Taper flange I-sections EN Test certificates The chemical composition and mechanical properties of all steel incorporated into structures shall be stated in a mill test certificate Surface condition Steel surfaces shall not be more heavily pitted or rusted than rust grade C of ISO Surface defects in hot-rolled sections, plates and wide flats revealed during surface preparation, and which are not in accordance with the requirements of SANS 1431, shall be rectified to comply with such requirements. Surface defects in hot-rolled hollow sections revealed during surface preparation and which are not in accordance with the requirements of EN , shall be rectified to comply with such requirements Welding consumables Standards Consumables for use in metal arc welding shall comply with the appropriate standards listed in table Storage Consumables shall be stored in accordance with the manufacturer s recommendations. Any drying or baking of consumables before use shall be carried out in accordance with the manufacturer s recommendations. 7

8 Table 2 Approved parent metal-filler weld metal combinations for steels acceptable for prequalified welding procedure standards Minimum yield strength MPa Parent metal Minimum ultimate tensile strength MPa or Process SMAW (Shielded metal arc welding) SAW (Submerged arc welding) GMAW (Gas metal arc welding) FCAW (Flux-cored arc welding) SMAW (Shielded metal arc welding) SAW (Submerged arc welding) GMAW (Gas metal arc welding) FCAW (Flux-cored arc welding) Electrode AWS A5.1 E70XX AWS A5.17 F7XX EXXX AWS A5.18 ER70S X AWS A5.20 E7XT X AWS A5.1 Filler weld metal Minimum yield strength MPa Minimum ultimate tensile strength MPa / E7015, E E7018, E7028 AWS A5.17 F7XX EXXX AWS A5.18 ER70S X AWS A5.20 E7XT X (except 2, 3, 10, 13, 14, GS) Structural fasteners Ordinary bolt assemblies The mechanical properties of bolts, screws and nuts shall be in accordance with the following standards, as stated in the specification data or indicated in the design drawings: a) Class 4.8, 8.8 and 10.9 bolts and screws: SANS b) Class 4 to 11 nuts: SANS Bolts, screws and nuts shall comply with the following standards: a) bolts: SANS or SANS b) screws: SANS or SANS c) nuts: SANS or SANS d) hot-dip galvanized bolts: SANS or SANS

9 NOTE 1 See for bolt/nut combinations. NOTE 2 The term "class" is used here to indicate the mechanical properties of the material of which a fastener is made. This is equivalent to the term "property class" which is used by ISO and in SANS 1700, or the term grade which has customarily been used in the steel construction industry High-strength friction-grip (HSFG) bolt assemblies HSFG bolt assemblies shall be in accordance with the provisions of SANS Through-hardened washers shall be in accordance with the provisions of SANS Holding-down (HD) bolts Holding-down bolts shall be fabricated from round bar that complies with the requirements of SANS 1431 grade 300WA Washers Plain material washers shall be in accordance with the provisions of SANS Throughhardened washers shall be in accordance with the provisions of SANS Shear studs Studs used in composite construction shall be the headed type with the following properties after being formed: a) Minimum yield strength (0,2 % offset): 345 MPa. b) Minimum ultimate tensile strength: 415 MPa. c) Elongation of 20 % on a gauge length of 5,65 A, where A is the area of the test specimen Substitution of steel quality and shape The steel quality or shape of components may be substituted if it can be demonstrated that all the relevant performance criteria of the original design will be satisfied. 4.2 Drawings General Standards All drawings shall be prepared in accordance with recognized industry standards. NOTE The Southern African Institute of Steel Construction publication, Southern African structural steelwork detailing manual, establishes industry standards for drawings Revisions Revised drawings shall have a term added to the drawing number and a description in the notes stating the changes that have been made and the date they were made. Furthermore, whenever possible, the most recent revisions to design drawings should be individually highlighted where they occur in the drawing. 9

10 Format of drawings Drawings that will be filed by microfilming for record purposes shall be prepared in accordance with SANS and as specified in the specification data Design drawings Design drawings shall include a general arrangement of the proposed structure with plans, cross sections, elevations and dimensions, indicating all the structural members with their respective sizes, material grades and special connections, and shall be sufficiently comprehensive to allow the detailing of all connections. Dimension figures in the drawings shall be deemed to be correct, even if the drawings are not to scale. No dimension shall be obtained from a drawing by scaling or determining the distance between lines or points by electronic means. Where necessary, the architectural or other relevant drawings shall also be provided. If applicable, the combinations of forces to be resisted by connections and any cambers, eccentricities and other information required for the design of connections shall be provided Holding-down bolt/interface drawings Holding-down bolt/interface drawings shall show the base location, level, orientation and details of members in contact with concrete or other supporting material, the supporting material as such, and any interface devices such as HD bolts, cast-in items or pockets Fabrication drawings General Fabrication drawings shall show all necessary details, dimensions, and all welding and welding inspection requirements to enable fabrication of components Attachments to facilitate erection The fabrication drawings shall show details of holes and fittings necessary for lifting and erecting components; such holes and fittings may remain part of the permanent structure, unless otherwise specified in the specification data. The detailing of welding of temporary attachments shall comply with the requirements in Packing, clearances and camber When preparing fabrication drawings, provision shall be made for a) packings which might be necessary to ensure proper fit-up of joints (see and ); b) the need for clearances between the fabricated components so that the permissible deviations in fabrication and erection are not exceeded (see 5.4); and c) the requirements for cambers Hole sizes Holes shown in the fabrication drawings shall be as follows: a) For ordinary bolts and HSFG bolts not exceeding 24 mm diameter: greater than 24 mm diameter: 2 mm greater than the bolt diameter. 3 mm greater than the bolt diameter. 10

11 b) For HD bolts less than 24 mm diameter: from 24 mm to 36 mm diameter: greater than 36 mm diameter: 6 mm greater than the bolt diameter. 10 mm greater than the bolt diameter. as specified in the specification data or shown in the design drawings. c) For fitted bolts: in accordance with Hole spacing The spacing between holes for fasteners and the distance between holes and edges shall comply with the relevant requirements of SANS and SANS Holding-down bolts HD bolt details shall include washers with holes not more than 3 mm greater than the HD bolt diameter; and the size and thickness of a washer shall be appropriate to the bolt diameter and size of the hole Connections to allow movement Where the specification data requires the connection to be designed to allow for movement, the bolt assembly used shall be detailed to remain secure without impeding the movement Machining Any machining requirements shall be clearly indicated in the fabrication drawings or described in the specification data Location of drilled holes The fabrication drawings shall indicate clearly those locations where holes shall only be made by drilling. NOTE 1 Common situations where drilling is mandatory are a) with non-slip connections for HSFG bolts, b) at locations where plastic hinges are assumed in the design, c) holes in regions susceptible to fatigue design constraints, and d) where the design code does not permit punched holes. NOTE 2 For guidance on punched holes see Faying surfaces with HSFG connections The surface finish assumed in the design of the friction grip connections together with the method or procedure to achieve such a surface shall be stated in the fabrication drawings Erection drawings Temporary steelwork Details and arrangements of temporary steelwork necessary for erection purposes shall be shown in the erection drawings. 11

12 Marking system (erection marks) Every assembly or part which is to be erected shall be allocated an erection mark. Members which are identical in all respects may have the same erection mark Erection mark drawings Erection mark drawings shall show plans and elevations at a scale such that the erection marks for all members can be shown. The drawings shall show the grid locations (as indicated in the design drawings), main dimensions, member levels and centre lines. Details at an enlarged scale should also be made if these are necessary to show the assembly of members "As erected" drawings The "as erected" drawings shall consist of one set of paper prints of all drawings which have been marked up after completion and acceptance of the steelwork, to reflect changes that have occurred. Such "as erected" drawings shall include a) general arrangement drawings or erection mark drawings, b) fabrication drawings, c) drawings made after fabrication to show revisions, and d) the fabrication drawing register. 4.3 Workmanship General Identification Material grade identification The material grades of all steel shall be positively identifiable, excluding grade 300WA. Where required in the specification data, all steel elements shall be marked so as to be traceable to a specific cast or heat of steel Marking of steelwork Individual pieces shall be identifiable at all stages of fabrication. Completed components shall be marked with a durable and distinguishing erection mark in such a way as not to damage the material. Hard-stamping may be used, except where otherwise stated in the specification data. Elements to be hot-dip galvanized shall be marked by hard-stamping or welded lettering. Water-based paint or an appropriate marking pen shall be used for any temporary marks on steel before galvanizing Handling Steelwork shall be bundled, packed, handled and transported in a safe manner so that permanent distortion does not occur and surface damage is minimized. 12

13 4.3.3 Cutting and shaping Cutting operations Cutting and shaping of steel may be carried out by shearing, cropping, sawing, nibbling, laser cutting, plasma cutting, water-jet cutting or machine-flame cutting. Where machine-flame cutting is impractical, hand-flame cutting may be used Flame-cut edges Flame-cut edges shall be dressed to remove irregularities and to achieve a smooth and straight surface, unless such edges are free from significant irregularities. Before galvanizing, 1,5 mm shall be ground from flame-cut edges to remove any signs of flame cutting Columns Columns with ends not in direct bearing or intended to be erected on packs or shims, shall be fabricated to the accuracy given in item 2 in table Columns which are intended to be in direct bearing shall be fabricated to the accuracy given in item 3 in table Column sections which are intended to be in direct bearing shall be prepared at the butting ends so that the permissible erection deviations can be complied with Machining The thickness of elements that require machining shown in the drawings shall indicate the minimum thickness after the machining operations Dressing Cut edges shall be dressed to remove dross, burrs and irregularities. Holes shall be dressed as required to remove burrs and protruding edges. Sharp edges shall be dressed Holing Matching All matching holes for fasteners or pins shall align with each other so that the fasteners can be inserted without undue force through the assembled members in a direction at right angles to the faces in contact. Drifts may be used but holes shall not be distorted Drilling through more than one thickness Drilling shall be permitted through more than one thickness where the separate parts are tightly clamped together before drilling Full size punching of holes Full size punching of holes shall be permitted when a) the permissible deviation on the distortion of the punched hole does not exceed that described in item 3 in table 4, b) the holes are free from burrs which would prevent solid seating of the parts when tightened, 13

14 c) the thickness of the material is not greater than the hole diameter plus 3 mm; nor greater than 12 mm, d) the component will not be subjected to fatigue, and e) the holes in mating surfaces of spliced connections are punched in the same direction Punching and reaming Punching is permitted without the conditions in , provided that the holes are punched at least 2 mm less in diameter than the required size and the hole is subsequently reamed to the full diameter Slotted holes Slotted holes shall be made by one of the following methods: a) punched in one operation; or b) formed by drilling two holes and completed by cutting; or c) machine-operated cutting Assembly All components shall be assembled within the permissible deviations specified in and in such a manner that they are not bent, twisted or otherwise damaged. Drifting of holes to align the components shall be permitted, but shall not cause damage or distortion to the final assembly Curving and straightening Curving or straightening of components during fabrication shall be performed by one of the following methods: a) mechanical means, taking care to minimize indentations or change of cross section; or b) the local application of heat, ensuring that the temperature is carefully controlled and does not exceed 650 C; or c) the induction-bending process where the procedure used includes careful temperature control. After curving or straightening, welds within the area of curving or straightening shall be visually inspected. Welds which are to be subjected to non-destructive examination shall have these tests carried out after curving or straightening Storage Stacking Fabricated components which are stored before being transported or erected shall be stacked clear of the ground and arranged, if possible, so that water cannot accumulate. They shall be kept clean and supported in such a manner as to avoid permanent distortion. 14

15 Visible markings Individual components shall be stacked and marked in such a way as to ensure that they can be identified. 4.4 Workmanship Welding General Welding activities shall be undertaken by appropriately qualified welders only (see 5.2) Welding processes Welding shall be a metal-arc process in accordance with ANSI/AWS D1.1/D1.1M, read in conjunction with this part of SANS Welding consumables shall be chosen to ensure that the mechanical properties of the weld metal are not less than those required for the parent metal. Approved parent metal and filler weld metal combinations are listed in table 2. For parent metals and filler weld metals which are not listed in table 2, ANSI/AWS D1.1/D1.1M shall be utilized. Joints shall be prepared in accordance with ANSI/AWS D1.1/D1.1M. Precautions shall be taken to ensure cleanliness of the connection before welding, and to ensure the required preheat temperatures Welding procedures All welding procedures shall be prepared in accordance with ANSI/AWS D1.1/D1.1M. The zinc coating on galvanized components shall be removed before welding in accordance with the welding recommendations related to coatings and the provisions of SANS A written welding procedure specification (WPS) shall be prepared for each different welding procedure to be used in fabrication. This shall include the prequalified procedures, which are exempt from tests. For the purpose of WPS prequalification, the parent metal-filler weld metal combination given in table 2 shall be taken to form part of table 3.1 in ANSI/AWS D1.1/D1.1M:2002. Welders, welding operators, tack welders and inspection personnel shall have access to the written prequalified WPS Assembly techniques Fit-up Joints shall be fitted up to the dimensional accuracy required by the welding procedure, depending on the process to be used Jigs Fabrications assembled in jigs may be completely welded in the jig, or may be removed from the jig after tack welding Tack welds Tack welds to be incorporated into main welds shall be made using the same procedures as for the root runs of main welds. The length of the tack shall be the lesser of four times the thickness of the thicker part or 50 mm, unless otherwise demonstrated by a weld procedure qualification. 15

16 Tack welds which are not defective may be incorporated into main welds provided that the welder is qualified in accordance with 5.2. However, where joints are welded using an automatic or mechanized process, the suitability of the tack weld used for incorporation into automatic processes shall be demonstrated in the weld procedure qualification. Where, in terms of the specification data or the design drawings, tack welds are not to be incorporated into final welds, they shall be removed. For statically loaded structures, they need not be removed Distortion control The sequence of welding a joint or a sequence of joints shall be such that distortion is minimized (see 5.4.1) Fabrication or erection attachments Welding of temporary attachments required for fabrication or erection purposes shall be made in accordance with the requirements for a permanent weld. When removal is necessary (as specified in the specification data), attachments shall be flame cut or gouged at a point not less than 3 mm from the surface of the parent material. The residual material shall be ground flush and the affected area visually inspected. When thicknesses are greater than 20 mm, attachments shall also be checked by magnetic particle inspection. Attachments shall not be removed by hammering Extension pieces (run on/run off pieces) Where the profile of a weld is maintained to the free end of a run by the use of extension pieces, they shall be of a material of a similar composition, but not necessarily the same grade, as the component. They shall be arranged so as to provide continuity of preparation and shall be removed after completion of the weld, and the surface shall be ground smooth Production test plates Where production test plates are required for testing purposes, they shall be clamped in line with the joint. The grade of material and rolling direction shall match the parent plate, but need not be cut from the same plates or cast Shear stud welding Welding of shear studs and the acceptance criteria shall be in accordance with ANSI/AWS D1.1/D1.1M Weld repairs Defective welds shall be replaced or repaired in accordance with ANSI/AWS D1.1/D1.1M. Repaired or replaced welds shall be re-tested. 4.5 Workmanship Bolting Ordinary bolted assemblies Bolt/nut combinations The combinations of bolts and nuts shall be not less than the following: a) class 4.8 bolts or screws with class 4 nuts in accordance with SANS ; or 16

17 b) class 8.8 bolts with class 8 nuts in accordance with SANS Any bolt assembly which seizes when being tightened shall be replaced Multiple bolt classes and diameters Different bolt classes of the same diameter shall not be used in the same structure Bolt length The bolt length shall be chosen such that, after tightening, at least one thread plus the thread runout will be clear between the nut and the unthreaded shank of the bolt and at least one clear thread shall show above the nut. Unless otherwise stated in the specification data, the maximum protrusion beyond the nut shall be 25 mm Washers Except in the case of fitted bolts, and unless otherwise required in terms of the specification data or specifically ordered, washers need not be used where surfaces are flat and flanges are untapered, and where holes have normal clearances. When the members being connected have already had the top/final coat of the surface protective treatment applied, and this treatment might be damaged by the nut or bolt head being rotated, a washer shall be placed under the rotating part. A suitable plate, or heavy-duty washer, shall be used under the head and nut when bolts are used to assemble components with oversize or slotted holes. Washers used in hot-dip galvanized assemblies shall also be hot-dip galvanized Taper washers When the bolt head or nut is in contact with a surface which is inclined at more than 3 from a plane at right angles to the bolt axis, a taper washer shall be used to achieve satisfactory bearing Galvanized nuts Nuts that are to be hot-dip galvanized shall be of a higher class than the associated bolt or screw. Nuts shall be checked after being galvanized for free running on the bolt and shall be re-tapped to the permissible deviations if necessary to ensure a satisfactory tightening performance Bolt tightening Bolts may be assembled using power tools or shall be fully tightened by hand using appropriate standard length spanners Fitted bolts Bolts that comply with the requirements for product grade A in accordance with SANS may be used as fitted bolts when holes are drilled or reamed after assembly so that the clearance in the hole is not more than 0,3 mm. 17

18 4.5.2 Fit-up and reaming when using ordinary bolts Fit-up Connected parts shall be firmly drawn together. If large distortion gaps (in excess of 2 mm) remain between the plies of the joint, it shall be taken apart and a pack or shim inserted or irregularities ground down Reaming Where parts cannot be brought together by drifting without distorting the steelwork, rectification may be made by reaming, provided that the design of the connection will allow for larger diameter holes and bolts High-strength friction-grip (HSFG) assemblies Bolt/nut/washer combinations HSFG bolt assemblies shall be in accordance with SANS Tightening The use of HSFG bolts shall comply with SANS Tightening of HSFG bolts shall be by the turn of nut method in accordance with SANS 10094, or with direct tension-indicating devices used in accordance with the manufacturer s recommendations Reuse of bolt assemblies in HSFG joints One reuse of class 8.8S bolts shall be acceptable. Class 10.9S or galvanized class 8.8S bolts shall not be reused Hot-dip galvanized assemblies A thread lubricant shall be used on all hot-dip galvanized HSFG assemblies that are to be tensioned in accordance with SANS Beeswax or molybdenum disulfide-based lubricants have proved suitable. Thread lubricants shall be applied to the threads away from the connection so as to prevent lubricant ingress into the faying surfaces Fit-up and reaming when using HSFG bolts Fit-up Connected parts shall be firmly drawn together with all bolts snug tight. If it is not possible at the snug tightened point to fully compact plies due to distortional out-of-flatness of interfaces, the joint shall be taken apart and a pack or shim inserted or high points ground down before recommencing the tightening procedure Reaming Where parts cannot be brought together by drifting without distorting the steelwork, rectification can be made by reaming, provided that the design of the connection will allow the use of larger diameter bolts. 18

19 4.6 Workmanship Erection General Handling and storage Components shall be handled and stored clear of the ground in such a manner as to minimize the risk of surface abrasion and damage. Fasteners and similar small fittings shall be stored under cover in dry conditions Damaged steelwork Any steelwork damaged during off-loading, transportation, storage or erection shall be restored to comply with the standards for fabrication as given in this part of SANS Column base plates and slabs Steel packings shall be used to allow the structure to be properly aligned and levelled and shall be of sufficient size to avoid local crushing of the concrete or distortion of the base plate under construction loads. Base packings shall be placed so that they do not prevent subsequent grouting from completely filling all spaces directly under the base plates. Base packings shall be left permanently in place Cladding Cladding of a structure can only commence following acceptance of the structure. Unless otherwise stated in the specification data, a structure shall have been aligned and levelled within the permissible deviations given in and grouting shall have been completed Site operations Hard standings The load spread under cranes and lifting plant shall not exceed the strength of the hard standing or that stated in the specification data Temporary restraints and supports until permanent features are built Temporary bracing or supports that will be necessary until walls, floors or other non-steel structures are built, shall be installed and kept in position as long as they are required Other temporary restraints or supports Temporary restraints during erection shall be removed after the structure has been aligned, levelled and plumbed, provided that sufficient steelwork or permanent bracing (or both) has been erected Erection loads No part of the structure shall be permanently distorted by stacking of materials or temporary erection loads during the erection process. 19

20 4.6.3 Alignment and levelling Alignment of parts of the structure Each part of the structure shall be aligned as soon as is practicable after it has been erected. Permanent connections shall not be made between members until a large enough portion of the structure has been aligned, levelled, plumbed and temporarily connected to ensure that members will not be displaced during subsequent erection or alignment of the remainder of the structure Temperature effects Unless otherwise specified, due account shall be taken of the effects of temperature on the structure and on tapes and instruments when measurements are made for setting out during erection, and for subsequent dimensional checks. The reference temperature shall be 20 C unless otherwise stated in the specification data Grouting of supports Timing All grouting shall be completed before cladding or loading is applied to the structure Preparation No bedding or grouting shall be carried out until enough of the structure has been aligned or, for multistorey buildings, until a sufficient number of bottom lengths of stanchions has been aligned, levelled and plumbed and adequately braced by means of other structural components that have been levelled and are securely held by their permanent connections. Steel wedges or packings or other levelling devices of adequate strength and rigidity shall be used to support the steelwork. Immediately before being grouted, the space and all pockets under the steel shall be cleared of all debris and free water Bedding of stanchions in foundation pockets Before steel sections are embedded in concrete, the complete specified corrosion protection system shall be applied to each member down to at least 100 mm below the level of the concrete. In the case of a paint system, an additional final coat of the specified protection shall be applied to at least 100 mm above and below the level of the concrete. Where grouting forms part of the works, stanchions in pocket bases shall be grouted with dense concrete that has a characteristic cube strength at 28 d of not less than that of the surrounding concrete base, or 20 MPa, whichever is the greater, and with a maximum aggregate size of 10 mm. At least two-thirds of the depth of the pocket shall be filled initially and the stanchions shall then remain undisturbed for at least 48 h (or an equivalent period where rapid-hardening or high alumina cement is used) after which the pocket shall be filled Site welding Site welding shall be carried out in accordance with 4.4. Welding shall not be permitted during inclement weather, unless adequate protective measures are taken Site bolting Site bolting shall be carried out in accordance with

21 5 Compliance with the requirements 5.1 General inspection of steelwork during manufacture Sufficient components shall be checked for dimensional accuracy and conformity to drawings, to prove that the manufacturing process is working satisfactorily. 5.2 Welder qualification Welders, welding operators and tack welders shall be qualified by a fabricator, steelwork erector or an independent testing agency, in accordance with the provisions of ANSI/AWS D1.1/D1.1M. 5.3 Non-destructive testing of welds Record of testing Records of the test results shall be kept by the fabricator or steelwork erector Visual inspection of welds All welds shall be visually inspected in accordance with ANSI/AWS D1.1/D1.1M, over the full length of the weld before non-destructive testing is performed. Any welds which will be rendered inaccessible by subsequent work shall be examined before the loss of access. A suitably qualified person for visual inspection of welds may be a welding inspector or a welder who can provide evidence of having been trained and assessed for competence in visual inspection of the relevant types of welds Surface flaw detection Where a closer examination of a weld surface is required, magnetic particle inspection shall be used in accordance with the recommendations given in ANSI/AWS D1.1/D1.1M. If magnetic particle inspection is impractical, dye penetrant inspection may be used in accordance with the recommendations given in ANSI/AWS D1.1/D1.1M. A suitably qualified person for surface flaw detection of welds may be a welding inspector or a welder who holds a current certificate of competence in surface flaw detection of the relevant types of work, from a nationally recognized authority Ultrasonic and radiographic examination Where ultrasonic or radiographic examination is required in terms of the specification data, it shall be made in accordance with ANSI/AWS D1.1/D1.1M. Operators carrying out final ultrasonic or radiographic examination of the weld shall hold a current certificate of competence from a nationally recognized authority Scope of inspection All welds shall be visually inspected and shall be deemed acceptable if the criteria given in the visual inspection acceptance criteria of ANSI/AWS D1.1/D1.1M are satisfied. Where non-destructive testing other than visual examination is required, it shall be so stated in the specification data. This information shall designate the categories of welds to be examined, the extent of each category, and the method or methods of testing. 21

22 5.4 Permissible deviations Accuracy of fabrication The permissible deviations in cross section, length, straightness, flatness, cutting, holing and position of fittings shall be in accordance with the provisions of tables 3 to Accuracy of foundations, walls and anchor bolts The permissible deviations for foundations, walls and anchor bolts shall be in accordance with the provisions of table Accuracy of erected steelwork The permissible deviations in erected steelwork shall be in accordance with the provisions of tables 8 and 9, taking account of the following: a) All measurements shall be taken in calm weather, and due note shall be taken of temperature effects on the structure (see ). b) The deviations shown for I-sections shall apply also to box and tubular sections. c) Where deviations are shown relative to normal centre lines of the section, the permissible deviation on cross section and straightness, given in 5.4.1, may be added. 22

23 Table 3 Permissible deviations in rolled components after fabrication 1 2 Aspect Permissible deviation ( ) 1 Cross section after fabrication In accordance with the relevant provisions of table 1 a. 2 Squareness of ends not intended for bearing See h is the overall width or depth of the section 3 Squareness of ends prepared for bearing Prepare ends with respect to the longitudinal axis of the member, see also h is the overall width or depth of the section 4 Straightness on both axes For compression members and beams (other than purlins and sheeting rails), L is the distance between points that are to be laterally restrained. For other members, L is the overall length 5 Length L Length after cutting measured on the centre line of the section or on the heel of angles L is the overall length 6 Curved or cambered Deviation from intended curve or camber at the mid-length of the curved portion when measured with the web horizontal L is the overall length a For ease of reference, see permissible deviations given in the structural steel tables in the Southern African Institute of Steel Construction publication, Southern African steel construction handbook (limit states design). 23

24 Table 4 Permissible deviations for elements of fabricated members Position of fittings Aspect Deviations from the intended position of fittings and components the location of which is critical to the force path in the structure, shall not exceed. Permissible deviation ( ) 2 Position of holes The deviation from the intended position of an isolated hole, or a group of holes, relative to each other, shall not exceed. 3 Punched holes The distortion caused by a punched hole shall not exceed (see ). D is the diameter of the punched hole 4 Sheared or cropped edges of plates or angles The deviation from a 90 edge shall not exceed. t is the thickness of the plate or angle 5 Flatness of load transfer areas Where bearing is specified, the flatness of load transfer areas shall be such that when measured against a straight edge not exceeding 1 m in length, which is laid against the bearing surface in any direction, the gap does not exceed. 24

25 Table 5 Permissible deviations in plate girder sections Depth Depth on centre line Aspect Permissible deviation ( ) h is the overall depth of the section 2 Flange width Width of either top or bottom flange B t is the width of the top flange B b is the width of the bottom flange 3 Squareness of section Out-of-squareness of flanges B is the width of the flange 4 Web eccentricity Intended position of web from one edge of flange b is the distance from the face of the web to the end of the flange 5 Flanges Out of flatness B is the width of the flange 6 Top flange of crane girder Out of flatness of the rail seat W is the rail width plus 20 mm 25

26 Table 5 (continued) Length Aspect L is the length on centre line Permissible deviation ( ) 8 Flange straightness Straightness of individual flanges L is the overall length of the member 9 Curved or cambered Deviation from intended curve or camber at midlength of curved portion when measured with web horizontal L is the overall length of the member 10 Web distortion Distortion on web depth or gauge length d is the depth of the web 11 Cross section at bearings Squareness of flanges to web h is the overall depth of the section 26

27 Table 5 (concluded) 1 2 Aspect 12 Web stiffeners out of plane of web Straightness of stiffener out of plane of web, after welding Permissible deviation ( ) d s is the depth of the web stiffener 13 Web stiffeners in plane of web Straightness of stiffener in plane of web, after welding d s is the depth of the web stiffener 14 Twist L is the overall length of the section 27

28 Table 6 Permissible tolerances in fabricated box sections Plate widths Width of B f or B w Aspect Permissible deviation ( ) B f and B w are the two orthogonal sides of a plate 2 Squareness Squareness at diaphragm positions h is the overall width or depth of the section 3 Plate distortion Distortion on width or gauge length W 4 Web or flange straightness Straightness of individual web or flanges L is the overall length of the member 5 Web stiffeners out of plane of web Straightness out of plane of web after welding d s is the depth of stiffener 28

29 Table 6 (concluded) 1 2 Aspect 6 Web stiffeners in plane of web Straightness in plane of web after welding Permissible deviation ( ) d s is the depth of stiffener 7 Length Length on centre line (L) 8 Curved or cambered Deviation from intended curve or camber at the mid-length of the curved portion when measured with the web horizontal L is the overall length of the member 9 Twist L is the overall length of the member 29

30 Table 7 Permissible deviations for foundations, walls and anchor bolts Foundation level Aspect Deviation from specified level Permissible deviation ( ) 2 Vertical wall Deviation from specified position at steelwork support point = ± 20 mm 3 Pre-set foundation bolt or bolt groups in pockets Deviation from the specified location and level and minimum movement in pocket x is the horizontal permissible deviation y is the vertical permissible deviation 4 Pre-set foundation bolt or bolt groups Deviation from the specified location, level and protrusion x is the horizontal permissible deviation y is the vertical permissible deviation 30

31 Table 8 Permissible deviations of erected components 1 2 Aspect 1 Position at column base Deviation of section centre line from the specified position Permissible deviation ( ) 2 Single-storey columns plumb Deviation of top relative to base, excluding portal frame columns, on main axes h s is the storey height 3 Multistorey columns plumb Deviation in each storey and maximum deviation relative to base H is the building height h s is the storey height 4 Gap between bearing surfaces (See , and table 3). h is the overall width or depth of a member 31