AS-NZS-4671-2001.pdf

AS/NZS 4671:2001 (Incorporating Amendment No. 1) Australian/New Zealand Standard Steel reinforcing materials AS/NZS 4671 AS/NZS 4671:2001 This Joint Australian/New Zealand Standard was prepared by Joint Technical Committee BD-084, Reinforcing and Prestressing Materials. It was approved on behalf of the Council of Standards Australia on 18 January 2001 and on behalf of the Council of Standards New Zealand on 9 March 2001. It was published on 2 April 2001. The following are represented on Committee BD-084: Association of Consulting Engineers, Australia Australian Chamber of Commerce and Industry Australian Post Tensioning Association Australian Steel Association AUSTROADS Bureau of Steel Manufacturers of Australia Cement (b) ISO 6935 does not contain specific requirements appropriate for reinforcement for earthquake-resistant structures; and (c) consequent differences in both the text and numerical values, although minor in nature, are too numerous to meet the strict definition of technically equivalent. In choosing to vary the above documents where they considered it necessary, the Committee took into account the fact that, to date, neither document has found wide acceptance. 2 Strength grades Only three strength Grades have been considered, i.e., those having lower characteristic yield strengths of 250 MPa, 300 MPa and 500 MPa respectively. The 500 Grade material replaces the Grade 400/450 Australian and the Grade 430/485 New Zealand materials, while 3 AS/NZS 4671:2001 the Grade 300 material corresponds closely to the current New Zealand Standard. Plain round material other than grade 300E is required to correspond to AS/NZS 3679. Requirements for Grade 500 steel have been developed from ENV 10080, while those for earthquake-resistant applications have been developed from the current edition of NZS 3402. 3 Ductility classes The need to provide reinforcement with ductility appropriate to earthquake-resistant concrete structures, coupled with recent investigations into the structural consequences of the relatively low ductility of cold-worked reinforcement, has led to the introduction of three ductility classes. These are distinguished in requirements by the letters L (low), N (normal) and E (earthquake), placed immediately after the strength-grade number, corresponding with different minimum values for uniform elongation and maximum stress to yield stress ratio. 4 Chemical and mechanical properties Adjustments have been made to the chemical composition, carbon equivalent, and mechanical properties parameters, as necessary, to satisfy the (sometimes conflicting) requirements of strength, ductility and weldability. 5 New inclusions In addition to the items noted above the following new material has been included: (a) Production control in all stages of manufacture is a specific requirement (Clauses 6.3 and 8) with the details of how it is to be achieved being spelt out in Appendix B. (b) Purpose-made meshes are covered in Clause 7.5.4 and distinguished from the commonly available meshes, whereas only stock meshes were previously specified. (c) Identification rules for the standard strength grades and ductility classes are given and illustrated in Clause 9 so that the different materials can be readily differentiated visually on site and distinguished from previously manufactured materials. (d) The bond test in Appendix C has been introduced as an alternative means for demonstrating the ability of deformed reinforcement to develop sufficient bond to achieve its characteristic yield strength when embedded in concrete. Statements expressed in mandatory terms in notes to tables are deemed to be requirements of this Standard. AS/NZS 4671:2001 4 CONTENTS Page FOREWORD5 1 SCOPE6 2 REFERENCED DOCUMENTS6 3 DEFINITIONS7 4 NOTATION8 5 CLASSIFICATION AND DESIGNATION9 6 MANUFACTURING METHODS 11 7 CHEMICAL, MECHANICAL AND DIMENSIONAL REQUIREMENTS11 8 SAMPLING AND TESTING FOR MANUFACTURING CONTROL.20 9 IDENTIFICATION.20 APPENDICES A MEANS FOR DEMONSTRATING COMPLIANCE WITH THIS STANDARD .23 B MANUFACTURING CONTROL .25 C REQUIREMENTS FOR DETERMINING THE MECHANICAL AND GEOMETRIC PROPERTIES OF REINFORCEMENT.33 D PURCHASING GUIDELINES40 5 AS/NZS 4671:2001 FOREWORD Prior to 1995, responsibility for the Australian/New Zealand Standards on steel reinforcing and prestressing materials lay with Committee BD-023, Structural Steels, whose interest and expertise were mainly oriented toward materials for steel structures rather than for concrete structures. In recognition of this and in pursuance of the Memorandum of Understanding between Standards Australia and Standards New Zealand, a new joint Australian/New Zealand committee (BD-084) was formed in December 1994 to take on the specific responsibility of upgrading and harmonizing the relevant reinforcing and prestressing materials Standards of both countries. At about this time, the results of international and local research indicated markedly different ductile behaviour between concrete members containing either hot-rolled or cold- rolled reinforcement. As this has consequent implications in the design and detailing for both normal and earthquake-resistant structures, concerns were being expressed regarding the status of the current high strength steels and, in particular, welded mesh. The Australian Standards most directly affected by the latter material are AS 2870, Residential slabs and footings, and AS 3600, Concrete structures. The Committees responsible for those Standards (BD-025 and BD-002 respectively) have reviewed the implications of the proposals in this Standard and as a result have taken the following actions: (a) The latest edition of AS 2870 (June 1996) permits the substitution of ribbed-wire meshes, on an equivalent strength basis with a minimum uniform elongation requirement, for the plain-wire meshes generally specified in that Standard and foreshadows the introduction of this Standard. (b) Committee BD-002 has set up a special Working Group to investigate the consequences, in both design and detailing requirements, of using low ductility steels for reinforcement. As an interim measure, Amendment 1 to AS 36001994 (August 1996) introduced limitations on the use of this material in negative moment regions and flagged other areas where caution in its use should be exercised. When the investigations have been completed and all the results assessed, it is anticipated that further amendments will be necessary and that they will be published at or about the same time as this Standard. While this Standard theoretically provides for three ductility classes and three strength grades, it should be realized that some of the possible combinations are not technically achievable in practice. Furthermore, from a simple commercial viewpoint, it is unlikely that all achievable combinations will be produced in either country. Specifically, it is envisaged that 500E steels are unlikely to be used in Australia, it being considered that Australia's generally low seismicity can be adequately accounted for by using Normal (N) class steels. Conversely, Normal class steels are unlikely to be used in New Zealand where the seismicity is generally high. It is felt that this joint Standard will enable a number of significant benefits to the concrete construction industry, namely (i) more efficient use of materials, and for designers to detail less congested reinforcing layouts (particularly in columns and walls) with the use of higher strength steels; (ii) more reliable member performance as a result of the clarification of minimum ductility levels; (iii) more uniform product as a result of tighter conformance requirements; and (iv) greater compatibility between design and production parameters (e.g. characteristic values), all of which should lead to more efficient, reliable and cost effective concrete structures. AS/NZS 4671:2001 6 COPYRIGHT STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand Standard Steel reinforcing materials 1 SCOPE This Standard specifies requirements for the chemical composition and the mechanical and geometrical properties of reinforcing steel used for the reinforcement of concrete in the form of (a) deformed or plain bars and coils; (b) machine-welded mesh; and (c) continuously threaded bars. This Standard does not apply to prestressing steels, stainless steel reinforcement, epoxy-coated steels and galvanized steels. NOTES: 1 Means for demonstrating compliance with this Standard are given in Appendix A. 2 Prestressing steels are covered by AS 1310, AS 1311, AS 1313. 3 Information on stainless steel reinforcement may be found in other internationally (accepted) Standards such as BS 6744 or ASTM A955M. 2 REFERENCED DOCUMENTS The following documents are referred to in this Standard. AS 1199 Sampling procedures and tables for inspection by attributes 1310 Steel wire for tendons in prestressed concrete 1311 Steel tendons for prestressed concrete 7-wire stress-relieved steel strand 1313 Steel tendons for prestressed concrete Cold-worked high-tensile alloy steel bars for prestressed concrete 1391 Methods for tensile testing of metals 1399 Guide to AS 1199Sampling procedures and tables for inspection by attributes 1554 Structural steel welding 1554.3 Part 3: Welding of reinforcing steel 2193 Methods for calibration and grading of force-measuring systems of testing machines AS/NZS 1050 Methods for the analysis of iron and steel 3679 Structural steel 3679.1 Part 1: Hot-rolled bars and sections ISO 15630-1 Steel for the reinforcement and prestressing of concreteTest methods, Part 1: Reinforcing bars, wire rod and wire 15630-2 Steel for the reinforcement and prestressing of concreteTest methods, Part 2: Welded fabric A1 7 AS/NZS 4671:2001 COPYRIGHT SAI HB 18 Guidelines for third-party certification and accreditation HB 18.28 Guide 28: General rules for a model third-party certification scheme for products 3 DEFINITIONS For the purpose of this Standard, the definitions below apply. 3.1Ageing Heating of the test specimen to 100 ±10°C, maintaining this temperature for a period of 1 h +15, 0 min and then cooling the specimen in still air to room temperature. 3.2 Bar A straight length of reinforcing steel. 3.3 Characteristic value 3.3.1 Lower characteristic value (CvL) The value of a property having a prescribed (high) probability (p) of being exceeded in a hypothetical unlimited series of standard tests. NOTE: The probability of a test value being below this value is (1 p) at a confidence level of 0.9. 3.3.2 Upper characteristic value (CvU) The value of a property having a prescribed (high) probability (p) of not being exceeded in a hypothetical unlimited series of standard tests. NOTE: The probability of a test value being above this value is (1 p) at a confidence level of 0.9. 3.4 Decoiled steel Reinforcing steel manufactured in coils and subsequently processed. 3.5 Deformed reinforcement 3.5.1 Indented reinforcement Reinforcing steel with at least two rows of transverse indentations, which are distributed uniformly along the entire length. 3.5.2 Ribbed reinforcement Reinforcing steel with at least two rows of transverse ribs, which are distributed uniformly along the entire length. 3.6 Mesh Longitudinal and transverse bars of the same or different diameter and length, which are arranged substantially at right angles and factory electrical resistance welded by automatic machines at points of intersection. 3.7 Mesh, length of The longest side of the mesh, irrespective of the manufacturing direction. 3.8 Mesh, longitudinal bars in The reinforcing steel in the manufacturing direction of the mesh. AS/NZS 4671:2001 8 COPYRIGHT 3.9 Mesh, overhang of Length of longitudinal or transverse bars projecting beyond the centre of the outer crossing bar in the mesh. For twin bar mesh, the overhang is measured from the midpoint line of the adjacent bars (see Figure 3). 3.10 Mesh, pitch of The centre-to-centre distance of bars in the mesh. For twin bar mesh, the pitch is measured between the midpoint of the adjacent bars (see Figure 3). 3.11 Mesh, purpose made Mesh manufactured according to specific requirements. 3.12 Mesh, transverse bars in Reinforcing steel perpendicular to the manufacturing direction of the mesh. 3.13 Mesh, twin bars in Two bars of the same designation placed adjacent to each other as a pair. 3.14 Mesh, width of The shortest side of the mesh, irrespective of the manufacturing direction. 3.15 Plain reinforcing steel Reinforcing steel without surface deformations excluding identifying marks. 3.16 Reinforcing steel Steel with a circular or practically circular cross-section, which is suitable for the reinforcement of concrete. 3.17 Rib, longitudinal Uniform continuous protrusion parallel to the axis of the reinforcing steel. 3.18 Rib, transverse Any protrusion on the surface of the product other than a longitudinal rib. 3.19 Steel producer The organization responsible for producing reinforcing steel in bar or coil form from a hot- rolling process. 3.20 Steel processor The organization responsible for subsequent processing of reinforcing steel supplied by a steel producer, which significantly changes the shape and properties of the steel. The processing may include cold-rolling, cold-drawing, decoiling and straightening, or automatic, electrical-resistance welding. 4 NOTATION The following symbols are used in this Standard. Agt = the percentage elongation at maximum force when tested in accordance with Appendix C, as a percentage As = the nominal cross-sectional area of a reinforcing steel, in millimetres squared a= pitch of bars in a mesh, in millimetres CvL = lower characteristic value of a variable parameter CvU = upper characteristic value of a variable parameter 9 AS/NZS 4671:2001 COPYRIGHT c= the longitudinal pitch of the transverse deformations measured parallel to the axis of the reinforcing steel, in millimetres d= the nominal diameter of a reinforcing steel, in millimetres fP = the specific projected area of transverse indentations fR = the specific projected area of transverse ribs g= the circumferential gap between deformations h= the rib height or indentation depth, in millimetres ki = a coefficient Ln = the nominal length of a bar, in millimetres n= the number of tests in a series of tests; or = the number of longitudinal bars in a particular trench mesh Re = the value of the yield stress (or 0.2% proof stress) determined from a single tensile test in accordance with AS 1391, in megapascals Rek.L = the lower characteristic value of the yield stress determined from a series of tensile tests, in megapascals Rek.U = the upper characteristic value of the yield stress determined from a series of tensile tests, in megapascals Rm = the value of the maximum tensile strength determined from a single tensile test in accordance with AS 1391, in megapascals u= edge overhang of a bar in a mesh, in millimetres wc =