EAST AFRICAN STANDARD

Transcription

1 EAS 412-2:2005 ICS EAST AFRICAN STANDARD Steel for the reinforcement of concrete Part 2: Ribbed bars EAST AFRICAN COMMUNITY EAC 2005 First Edition 2005

2 EAS 412-2:2005 Foreword Development of the East African Standards has been necessitated by the need for harmonizing requirements governing quality of products and services in East Africa. It is envisaged that through harmonized standardization, trade barriers which are encountered when goods and services are exchanged within the Community will be removed. In order to achieve this objective, the Partner States in the Community through their National Bureaux of Standards, have established an East African Standards Committee. The Committee is composed of representatives of the National Standards Bodies in Partner States, together with the representatives from the private sectors and consumer organizations. Draft East African Standards are circulated to stakeholders through the National Standards Bodies in the Partner States. The comments received are discussed and incorporated before finalization of standards, in accordance with the procedures of the Community. East African Standards are subject to review, to keep pace with technological advances. Users of the East African Standards are therefore expected to ensure that they always have the latest versions of the standards they are implementing. East African Community 2005 All rights reserved * East African Community P O Box 1096 Arusha Tanzania Tel: /8 Fax: / eac@eachq.org Web: * 2005 EAC All rights of exploitation in any form and by any means reserved worldwide for EAC Partner States NSBs. ii EAC 2005 All rights reserved

3 I_ w _ INTERNATIONAL STANDARD IS First edition o mm ^ _-.-_I~-L em- Steel for the reinforcement of concrete - Part 2: Ribbed bars Acier 3 b&ton pour armatures passives - h-tie 2: Barres nervw&es Reference number IS : 1991 (E)

4 IS :1991(E) Contentq Page 1 scope..._ Normative references Definitions Dimensions, masses and tolerances Geometry of ribs Chemical composition Mechanical properties Testing of mechanical properties Designation... 6 IO Marking Certification and inspection Test report... 7 Annexes A Two multinational systems for identification of ribbed bars Options for agreement between purchaser and supplier... IO C Bibliography...f IS All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. lnternationai Organization for Standardization Case hxtale 56 l CH-1211 Genhve 20 l Switzerland Printed in Switzerland ii

5 IS0 6935=2:1991(E). Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the techtiical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS was prepared by Technical Committee ISO/TC 17, Steel, Sub-Committee SC 16, Steels for fhe reinforcerr)ent and prestressing of concrete. IS consists of the following parts, under the general title Steel for the reinforcement of concrete: - Part 1: Plain bars - Part 2: Ribbed bars - Part 3: Welded fabric Annexes A, E3 and C of this part of IS are for information only.... III

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7 INTERNATIONAL STANDARD IS0 6935=2:1991(E) Steel for the reinforcement of concrete -. Part 2: Ribbed bars 1 Scope This part of IS specifies technical requirements for ribbed bars designed for reinforcement in ordinary concrete structures and for nonprestressed reinforcement in prestressed concrete structures. Five grades of steel are defined. Of these, RB 300, RB 400 and RB 500 should be considered as difficult to weld. The other two grades of steel, RB 400W and RB 5OOW, are readily welded by conventional welding procedures. This part of IS applies to hot-rolled steel without subsequent treatment. to hot-rolled steel with controlled cooling and tempering and to coldworked steel. The production process is at the discretion of the manufacturer. It also applies to reinforcement supplied in coil form. The requirements of this part of IS apply to the straightened product. Ribbed bars produced from finished products, such as plates and railway rails, are excluded. Steel bars for use as lifting hooks are also not included. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of IS At the time of publication, the editions indicated were valid. All standards are subject to revision, and patties to agreements based on this part of IS are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS :1989, Selection and preparation of samples and test pieces of wrought steels - Part 2: Samples for the determination of the chemical composition. IS0 404:1981, Steel and steel products - General technical delivery requirements. IS0 6892:1984, Metallic materials -- Tensile testing. IS :1990, Steel bars for reinforcement of concrete - Bend and rebend tests. IS :1991, Certification scheme for steel bars and wires for the reinforcement of concrete structures. 3 Definitions For the purposes of this part of IS0 6935, the following definitions apply. 3.1 cast analysis: Chemical analysis of a sample of the molten steel during casting. 3.2 certification scheme: Certification system as related to specified products, processes or services to which the same particular standards and rules, and the same procedure, apply. [ISO/IEC Guide characteristic value: Value having a prescribed probability of not being attained in a hypothetical unlimited test series. [ISO NOTE 1 Equivalent to fractile, which is defined in IS core: The part of a cross-section of the bar that contains neither longitudinal nor transverse ribs.

8 IS :1991 (E) 3.5 longitudinal rib: A uniform continuous rib parallel to the axis of the bar, before cold twisting in the case of cold-twisted bars. 3.6 nominal cross-sectional area: The crosssectional area equivalent to the area of a circular plain bar of the nominal diameter. 3.7 pitch, P (for twisted bars only): The distance betweentwo consecutive corresponding points of a longitudinal rib on the same generatrix. 3.8 product analysis: Chemical analysis of a sample from a ribbed bar. 3.9 rib height, a: The distance from the highest point on the rib (transverse or longitudinal) to the surface of the core, to be measured normal to the axis of the bar. (See figure 2) rib spacing, c: The distance between the centres of two consecutive transverse ribs measured parallel to the axis of the bar. (See figure 1.) 3.11 transverse rib: Protuberance at an angle, either perpendicular or oblique, to the longitudinal axis of the bar transversal ribless perimeter, xfi: The sum of the distances along the surface of the core between the transverse ribs of adjacent rows measured as the projection on a plane perpendicular to the bar axis transverse rib inclination, /I: The angle between the transverse rib and the longitudinal axis of the bar. (See figures 1, 3, 4 and 5.) 4 Dimensions, masses and tolerances Dimensions, masses and tolerances are qiven. in table 1. Table 1 - Dimensions, masses and tolerances Nominal bar diameterl) Nominal cross-sectional area Mass pe Requirement mm mm* kg/m 6 28,3 0, ,3 0, ,3 0, , , , , , ,86 length Permissible deviation*) T5 f5 75 T5 T4 T4?4-1) If diameters larger than 40 mm are required, the size increase should be in increments of 5 mm. Permissible deviation on such bars is Oh. 2) Permissible deviation refers to a single bar. Delivery length should be agreed between manufacturer and purchaser. Preferred standard lengths of straight bars are 12 m or 18 m. Permiss~b$ deviation on delivery length from rollinq L mill: o mm. 5 Geometry of ribs Ribbed bars shall have transverse ribs. Longitudinal ribs are optional. The geometry of ribs shall ensure that the bars have adequate bond properties to fulfil their function in concrete structures. The bond properties are adequate if there are at least two rows of transverse ribs equally distributed around the perimeter. The transverse ribs within each row shall be distributed uniformly over the entire length of the bar, except in the area of marking. Requirements for rib geometry are given in table 2.. 2

9 IS0 6935=2:1991(E) Table 2 - Requirements for rib geometry Diameter Hot-rol ed bar Twisted bar l? Ribs of Crescent- Crescent-shaped mm uniform height shaped ribs ribs Height of transverse ribs, n Minimum p-p---, Height of longitudinal ribs, n Minimum All 0,05 I) 0,065 l.> 0,052 l? 0,065 D All 0,07 0 Rib spacing, c Minimum to maximum Transverse rib inclination, /? Minimum Transversal ribless perimeter, Cf;- Maximum Nominal pitch, P I -- 6 to All All All -. 0,5 n to 0,7 n 0,5 D to l,o I> 0,5 n to 0,7 I) 0,5 D to 0,8 n I 0.5 I) to l,o n 0,5 n to 1,2 D 0,5 n to 0,8 D 0,5 11 to l,o I> 35O 35O 35O 0,25 1, 0,35 II -- 10n+2lI - Dimensions defining the rib geometry in table2 are shown in figures I to 5. Figure 1 - Ribbed bar - Definitions of geometry -Rib Rounded transition Figure 3 - Example of non-twisted bar with varying rib inclinations to the longitudinal axis Figure 2 - Rib flank inclination, a, and rib height, n- Section A-A from figure 1 Figure 4 - Example of non-twisted bar with transverse ribs of uniform height (/3=90 ) 3

10 IS :1991 (E) Table 3 - Chemical composition - Maximum values in percentage by mass Steel grade Cl) Si Mn P S N2) ce, ) RB 300 RB ,060 0,060 RB 500 (0,070) 1 ---_I RB 400W 0,22 0,60.1,60 0, z-/-;;;--/--.-r:::. RB SOOViI (0,24)3) uk65) (1,70) Psw 1) For RB 400W and RB 500W with diameters larger than 32 mm, the maximum carbon content (C) is 0,25 % (0,27 %) and the maximum carbon equivalent (C,,) is 0,55 oh (0,57 Oh). 2) A higher nitrogen content may be used if sufficient quantities of nitrogen-binding elements are present. 3) The values in brackets apply for the product analysis. Figure 5 - Twisted bar with oblique ribs Table 4 - Characteristic values for upper yield stress, tensile strength and percentage elongation after fracture Steel grade Upper yield Tensile stress strength R eh R, N/mm2 N/mm2 Elongation A 5,65 RB O/o Rib spacing shall be taken as the mean value measured along one pitch. RB 400 RB 400W _ Chemical composition 500 RB 500W The steel shall not contain quantities of the given elements higher than those specified in table 3. The carbon equivalent, C,,, is calculated according to the formula C --- where C, Mn, Cr, V, MO, Cu and Ni are percentages by mass of the respective elements of the steel. 7 Mechanical properties 7.1 Tensile properties Required tensile properties for the various steel grades are given in table4. At least 95 O/o of the population under consideration shall have tensile properties equal to or above the characteristic values specified. Jo single test result shall be less than 95 % of the characteristic value given in table 4. By agreement between manufacturer and purchaser, the values in table4 may be used as guaranteed minimum values. The ratio of tensile strength to yield stress for each test specimen shall be at least 1,05. A type test of the product shall demonstrate that the total elongation at maximum force,.aql, is equal to or larger than 2,5 %. For steels that have no significant yield stress, the proof stress, R,, 12, shall be used to define the yield stress. 7.2 Bending properties After testing, none of the test pieces shall show fractures or cracks visible to the naked eye.

11 IS :1991 (E) 7.3 Rebending properties By agreement between manufacturer and purchaser, the rebend test may replace the bend test for steel grades RB 400, RB 4OOW, RB 500 and RB 500W. The rebend test is used to verify the ageing properties of bent bars. Aier testing, none of the test pieces shall have fractures or cracks visible to the naked eye. 7.4 Fatigue properties If required by the purchaser, the manufacturer shall demonstrate the fatigue properties of the product. 8 Testing of mechanical properties 8.1 Tensile test The tensile test shall be carried out according to IS For the determination of elongation after fracture, the original gauge length shall be 5 times the nominal diameter. For calculation of mechanical properties, the nominal cross-sectional area shall be used. 8.2 Bend test The bend test shall be carried out according to IS The test piece shall be bent to an angle between 160 and 180 over a mandrel of the diameter specified in table Rebend test The rebend test shall be carried out according to IS The test piece shall be bent over a mandrel of the diameter specified in table 6. The angle of bend before heating (ageing) shall be 90, and the angle of rebend shall be 20. Both angles shall be measured before unloading. Table 5 - Mandrel diameter to be used for the bend test Dimensions in millimetres Nominal diameter ) of bar Steel grade *. -- RB w--e.---_-_-me e--.-e RB RB W me w----v m-e RB 500 RB 500W ) For nominal diameters larger than 40 mm, the mandrel diameter in bend tests shall be agreed between manufacturer and purchaser. -- Nominal diameter of bar._-- Steel grade Table 6 - Mandrel diameter to be used for the rebend test v---w Dimensions in millimetres _----,-WV --. w----v RB 400 RB 400W RB 500 RB 500W

12 IS :1991 (E) 9 Designation Ribbed bars according to this part of IS shall be designated in the following order: - reinforcing steel.; - the number of this part of IS (IS Z); - nomitial diameter, in millimetres, according to table 1; - steel grade. Example: Reinforcing steel IS RB 500W IO Marking 10.1 Marking on the bar All bars should be identifiable by marks introduced during rolling which indicate: - th,e steel grade; - the name of the manufacturer. Some examples of multinational marking systems are shown in annex A Testing of a specific delivery Provisions regarding the nature, extent and evaluation of acceptance tests on deliveries of reinforcing steel not subject to a certification scheme are given in 11.3 and Testing of a specific delivery shall be performed according to By agreement between manufacturer and purchaser, 11.4 may be used Verification of characteristic values Organization The tests shall be organized and carried out according to an agreement between purchaser and manufacturer, taking into consideration the national rules of the receiving country Extent of sampling and testing For the purpose of testing, the delivery shall be subdivided into test units with a maximum mass of 50 t or a fraction thereof. Each test unit shall consist of products of the same steel grade and the same nominal diameter from the same cast. The manufacturer shall confirm in the test report that all samples in the test unit origin; te from the same cast. The chemical composition cast analysis) shall be stated in this test report Marking of bundles Test pieces shall be taken foilows: from each test unit as Each bundle of bars of at least 500 kg shall have a label stating the manufacturer, number of this part of IS (lso ), steel grade, nominal diameter, cast number or reference related to test record and country of origin. 11 Certification and inspection Certification and inspection of reinforcement shall be performed - ina ccordance with a certifi tore Id by an externa I body; cation scheme moni- - according to testing of a specific delivery. 11.l Certification scheme In the case of a certification scheme, certification and inspection shall be performed in accordance with IS a) two test pieces from var -il ous bars for testing chemical composition (product analysis); b) fifteen test pieces (if appropriate 60 test pieces; see ) from various bars for testing all other properties specified in this part of IS Evaluation of the results Inspection by variables For properties which are specified as characteristic values, the following shall be determined: a) all individual values, xi, of the 15 test pieces (t2 = 15) b) the mean value, ml, (for 12 = 15) c) the standard deviation, q5 (for yt = 15). The test unit corresponds to the requirements if the condition stated below is fulfilled for all properties: ml5-2,33 x s15 > & the 6

13 IS :1991 (E) is the required characteristic value; 2,33 is the value for the acceptability index, k, for 12 = 15 for a failure rate of.5 % 0, = 0,95) at a probability of 90 % (1 -a = 0,90). If the condition stated above is not fulfilled, the index f +5 k I m15 - k is determined from the test results available. Where k > 2, testing can be continued. In this case 45 further test pieces shall be taken and tested from different bars in the test unit, so that a total of 60 test results are available (n = 60). The test unit shall be considered to comply with the requirements if the condition stated below is fulfilled for all properties: 4;o- I,93 x $6, > fk where I,93 is the value for the acceptability index, k, for 12 = 60 for a failure rate of 5 % (p = 0,95) at a probability of 90 % (1 - oc = 0,90) Inspection by attributes When testing properties specified as maximum or minimum values, all results determined on the 15 test pieces shall comply with the requirements of this part of IS In this case the test unit shall be considered to comply with the requirements. The tests may be continued when at most 2 results not conforming to conditions occur. In this case 45 further test pieces from various bars in the test unit shall be tested, so that a total of 60 test results are available. The test unit complies with the requirements if at most 2 of the 60 results do not conform to the conditions Chemical composition 11.4 Verification of guaranteed minimum values Tests shall be carried out according to the following. - Bars of the same cast shall constitute one group. For every 50 t or fraction thereof, one tensile and one bendkebend test shall be carried out for each bar diameter. - Each individual test result shall meet the required values in table4 and the required bending/rebendinq. properties in 7.2 and One cast analysis shall be carried out for every cast to verify chemical composition (clause 6). Samples shall be taken in accordance with IS If any test result does not meet the requirements, retests may be carried out, according to IS The manufacturer shall submit a test report stating that products of the delivery satisfy the chemical and mechanical properties defined in clauses 6 and 7, and a confirmation that the other requirements of this part of IS are fulfilled. 12 Test report The test report shall contain the following infor- \ mation: a) designation of the reinforcing steel according to this part of IS0 6935; b) marking on the reinforcing steel; c) date of testing; d) mass of the test unit; e) t&t results. Both test pieces shall comply with the requirements in this part of IS

14 IS :1991 (E) Annex A (informative) Two multinational systems for identification of ribbed bars A.1 References Euronorm 80-85, Reinforcing steel (not for prestressing) - Technical delivery conditions. ASTM A 615 M-88, Deformed and plain billet-steel bar-s for concrete reinforcement (metric). CSA G30.12-M1977, inforcement. A.2 Example No. 1 Billet steel bars for concrete re- System according to EURONORM A.2.1 Marking of the steel grade The steel grade shall be recognizable as follows from the product s surface features (arrangement of the oblique ribs). A Steel grade RB 400W is indicated by means of two opposed rows of parallel oblique ribs. The oblique ribs are at different intervals on each half of the circumference (see figure A.1). Cold-twisted RB 400 reinforcing steel is marked by twisted longitudinal ribs, with the same interval between the oblique ribs on each half of the circumference. A Steel grade RB 500W is indicated by means of two rows of oblique ribs, one row consisting of parallel oblique ribs and the other of ribs with alternating angles of inclination towards the axis of the bar (see figure A.2). Cold-twisted RB 500W reinforcing steel is indicated by additional twisted longitudinal ribs. A.2.2 Marking of the country and producing works A The country in which the steel was produced, and also the producer, is indicated by means of an arrangement of normal oblique ribs between thickened oblique ribs (see figures A.1 and A.2). A The symbol denoting the start of reading of the identification and its direction consists of one normal oblique rib between two thickened ones (see figures A.I and A.2). A The country of origin marking is shown in table A.I. Germany Table A.1 - Marking of country of origin ~ ~ Number of normal oblique Country ribs between two thickened oblique ribs Belgium, Netherlands, Luxemburg France Italy UK, Ireland Denmark, Sweden, Norway, Finland Spain, Portugal Greece, Turkey, Czechoslovakia A According to an index to be individually prepared for each country the mark for the steel producer contains: a) a group of normal oblique ribs (at least two); b) several groups of normal oblique ribs (once again separated by a thickened oblique rib), the number of normal ribs in the last group being at least two.

15 IS0 6935=2:1991(E) A.3.2 Each producer shall identify the symbols of his marking system. Direction of reading A.3.3 All bars shall be identified by a distinguishing set of marks legibly rolled into the surface of one side of the bar to denotc 2, in the following order: w++- Start Country Works No. 8 No. 1 Figure A.1 - Marking of reinforcing steel RB 400 (not cold-twisted) A.3.3.l Point of origin Letter or symbol designation A establl Size designation. ished as the producer s mill Arabic numeral corresponding to bar designation number (nominal diameter) Direction of reading t A Type of steel I WV- v- Start Country No. 4 Works No. 16 Figure A.2 - Marking of reinforcing steel RB 500W (not cold-twisted) A.3 Example No. 2 Letter S, if the bar is produced according to the specification in ASTM A 615 M. No mark, if the bar is produced according to CSA G30.12-Ml977 A Minimum yield designation For steel grade RB 400, either the number 4 (ASTM) or 400 (CSA) or a single continuous longitudinal line through at least five spaces offset from the centre of the bar side. (No marking designation for grade 300 bars) System according to ASTM A 615 M-88 A.3.1 When loading for mill shipment, bars shall be properly separated and tagged with the manufacturer s cast or test identification number. Direction of reading - x IO --e-+---j s 4 Works Bar According Steel symbol size to ASTM grade Figure A.3 - Marking according to ASTM A 615 M - 88

16 IS :1991(E) Annex B (informative) Options for agreement between purchaser and supplier For convenience, the provisions for which this part of IS indicates that additional or deviating requirements can be agreed between purchaser and supplier are listed below. The list does not imply any restriction on agreements concerning other provisions. - Diameter > 40 mm (tables 1 and 5). - Delivery length (clause 4). -- Longitudinal ribs (clause 5). - Guaranteed minimum values (7.1 and 11.4). - Rebending properties (7.3). - Fatigue properties (7.4). -- Organization of delivery testing (I 1.3.1).

17 IS :1991(E) Annex C (informative) Bibliography [I] IS0 3534:1977, statistics - Vocabulary and symbols. [ZJ IS0 8930:1987, General principles on reliability for structures -- List of equivalent terms. [3] ISO/IEC Guide 2, General ferms and their de/initions concerning standardization and related activities. 11

18 weme---- IS :1991(E) UDC 669.li122.4~422.11: : Descriptors: concrete, reinforced concrete, steels, reinforcing steels, reinforcing bars, round bars, specifications, dimensions, designation, marking, certification, inspection. Price based on 11 pages

19 EAC 2005 All rights reserved EAS 412-2:2005