1、BRITISH STANDARD BS ISO 6446:1994 Implementation of ISO6446:1994 Rubber products Bridge bearings Specification for rubber materials ICS 83.140;93.040BSISO6446:1994 This BritishStandard, having been prepared under the directionof the Sector Board forMaterials and Chemicals, waspublished under the aut
2、horityof the Standards Boardand comes into effect on 15June1996 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PRI/73 Draft for comment85/38034DC ISBN 0 580 25916 1 Committees responsible for this BritishStandard The preparation of this BritishStand
3、ard was entrusted to Technical Committee PRI/73, Industrial rubber products, upon which the following bodies were represented: British Rubber Manufacturers Association British Structural Bearing Manufacturers Association Building Employers Federation Department of Transport (Highways Agency) Institu
4、te of Biomedical Science Institution of Structural Engineers Malaysian Rubber Producers Research Association Ministry of Defence Royal Society of Chemistry Amendments issued since publication Amd. No. Date CommentsBSISO6446:1994 BSI 12-1999 i Contents Page Committees responsible Inside front cover N
5、ational foreword ii Foreword iii Text of ISO 6446 1BSISO6446:1994 ii BSI 12-1999 National foreword This BritishStandard reproduces verbatim ISO6446:1994 and implements it as the UK national standard. This BritishStandard is published under the direction of the Sector Board for Materials and Chemical
6、s whose Technical Committee PRI/73 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and
7、 promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI,389 Chiswick High Road, London W44AL. Additional information This standard has been issued to provide an internationally recognized material specification fo
8、r the rubber used in elastomeric bridge bearings. It is not intended as an alternative to BS5400-9.2:1983 which details the national requirements for materials, manufacture and installation of bridge bearings. Nor is it intended as an alternative to the forthcoming European specifications for these
9、products. BS5400-9.2 contains requirements relevant to the UK climate and the European specifications address European needs and thus do not cater for bridge bearings used in other climates. This standard does not specify design considerations and tests undertaken on finished bearings; for these, re
10、ference should be made to other relevant standards. This standard contains a number of options to accommodate differences in specifications and requirements between countries and between regions. Attention is drawn to clause7 which lists the minimum requirements for a specification. Note that the re
11、quirements for grades3 and4 relating to low temperature resistance are identical. When a material is formulated for these grades, consideration should be given to the longer period of use at sub-zero temperatures applying to grade4 (see4.3.2). Such exposure will normally call for a rubber compound t
12、hat has adequate resistance to low temperature crystallization and so is resistant to stiffening on storage. It is intended that a suitable test for low temperature crystallization will be incorporated in the next revision of this standard. A British Standard does not purport to include all the nece
13、ssary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theISO
14、title page, pagesii toiv, pages1 to8 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BSISO6446:1994 ii BSI 12-1999 Contents Page Foreword iii Introduction 1 1 Scope
15、 1 2 Normative references 1 3 Definitions 2 4 Materials 2 5 Test pieces 3 6 Test requirements 3 7 Details required for a specification 4 Annex A (normative) Assessment of adhesion in laminated bridge bearings 7 Annex B (informative) Alternative rubber materials 8 Figure A.1 Shear-break test piece an
16、d test 7 Table 1 Specification for performance properties 5 Table 2 Low-temperature test conditions 5 Table 3 Specification for quality control properties 6 Table B.1 Tentative quality control requirements for alternative rubber polymers 8BSISO6446:1994 BSI 12-1999 iii Foreword ISO (the Internationa
17、l Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been es
18、tablished 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. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardi
19、zation. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO6446 was prepared by Technical Committee
20、ISO/TC45, Rubber and rubber products, Subcommittee SC4, Miscellaneous products. Annex A forms an integral part of this International Standard. Annex B is for information only.iv blankBSISO6446:1994 BSI 12-1999 1 Introduction This International Standard has been prepared in order to assist national s
21、tandards organizations and other bodies wishing to devise a material specification for rubbers used in elastomeric bridge bearings. It represents a consensus viewpoint, and in doing so recognizes that practices and conditions of service are not the same, and in many cases cannot be the same, in all
22、areas of the world. For this reason, it includes a number of options among its requirements, for example with regard to low-temperature performance. The intention is that the user of this International Standard will select and specify the options most appropriate to his particular needs. The require
23、ments of this specification may be divided into two general categories, namely basic and optional. The basic requirements are those relating to choice of rubber type, overall hardness range, specification of shear modulus or nominal hardness, ozone resistance and source and preparation of test piece
24、s. Furthermore, an ability to form a strong adhesion bond is an essential requirement of a rubber used in a laminated bearing. These requirements are essential for a material specification based on this International Standard, although there is an option within each requirement. In addition, tensile
25、 strength, elongation at break, compression set and an accelerated-ageing test are specified as quality control requirements; in these cases, the test conditions and limits vary with rubber type. Those tests relating to tear strength and resistance to creep are optional and may be added to the speci
26、fication as appropriate. It is acknowledged that requirements for the rubber constitute only part of a specification for elastomeric bridge bearings. A complete specification will include statements on the characteristics and quality of reinforcement in laminated bearings and on sampling and frequen
27、cy of testing as well as load/deflection tests conducted on the complete bearing. 1 Scope This International Standard specifies requirements for rubber materials used in elastomeric bridge bearings, which may be of the plain-pad or laminated type. It also specifies methods of test and describes proc
28、edures for the preparation of test pieces from finished bearings. This International Standard does not contain aspects relating to design properties and quality control of the complete bearing, except where the complete bearing is used as the source of samples and test pieces to determine properties
29、 of the rubber material. Dimensions and tolerances are therefore not included in this International Standard. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the
30、 editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of curr
31、ently valid International Standards. ISO 34-1:1994, Rubber, vulcanized or thermoplastic Determination of tear strength Part1: Trouser, angle and crescent test pieces. ISO 36:1993, Rubber, vulcanized or thermoplastic Determination of adhesion to textile fabric. ISO 37:1994, Rubber, vulcanized or ther
32、moplastic Determination of tensile stress-strain properties. ISO 48:1994, Rubber, vulcanized or thermoplastic Determination of hardness (hardness between10 IRHD and100 IRHD). ISO 188:1982, Rubber, vulcanized Accelerated ageing or heat-resistance tests. ISO 471:, Rubber Times, temperatures and humidi
33、ties for conditioning and testing 1) . ISO 812:1991, Rubber, vulcanized Determination of low-temperature brittleness. ISO 813:1986, Rubber, vulcanized Determination of adhesion to metal One-plate method. ISO 815:1991, Rubber, vulcanized or thermoplastic Determination of compression set at ambient, e
34、levated or low temperatures. ISO 1431-1:1989, Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part1: Static strain test. ISO 1827:1991, Rubber, vulcanized or thermoplastic Determination of modulus in shear or adhesion to rigid plates Quadruple shear method. ISO 4661-1:1993, Rubber,
35、vulcanized or thermoplastic Preparation of samples and test pieces Part1: Physical tests. ISO 8013:1988, Rubber, vulcanized Determination of creep in compression or shear. 1) To be published. (Revision of ISO471:1983 and ISO1826:1979)BSISO6446:1994 2 BSI 12-1999 3 Definitions For the purposes of thi
36、s International Standard, the following definitions apply. 3.1 elastomeric bridge bearing a block of vulcanized rubber, with or without internal reinforcement, that is placed between the bridge deck and bridge support for the purpose of accommodating potentially damaging movements of the bridge deck
37、 resulting from the thermal expansion or contraction, the action of traffic, wind and other effects 3.2 plain-pad bearing a bearing consisting wholly of rubber 3.3 laminated bearing a bearing consisting of rubber with one or more reinforcing layers embedded in, and bonded to, the rubber 3.4 reinforc
38、ing layer a rigid or inextensible layer sandwiched between rubber layers in a laminated bearing for the purpose of increasing the compressive stiffness of the bearing without increasing its shear stiffness. The layer is usually a steel plate or textile fabric 3.5 rubber polymer the polymer type upon
39、 which the vulcanized rubber is based NOTE 1In this International Standard, the terms “rubber” and “rubber material” refer to the compounded and vulcanized material used in the bearing. 4 Materials 4.1 Composition Unless otherwise specified, the rubber material used in the bearing shall be vulcanize
40、d and shall be made of chloroprene rubber (CR) or natural rubber (NR). If other rubbers are used, their nature shall be disclosed. No reclaim rubber or vulcanized waste shall be used. The performance requirements to be met are given in Table 1 and Table 2 and the quality control requirements for chl
41、oroprene rubber (CR) and natural rubber (NR) are given in Table 3. Suggested quality control requirements for other rubbers are given in Annex B. NOTE 2Most practical experience with elastomeric bearing pads has been established with chloroprene rubber (CR) and natural rubber (NR) and the requiremen
42、ts for quality control are based on these rubbers. It is intended that the tentative values given in Annex B for other rubbers will be included in Table 3, in the light of experience, in subsequent editions of this International Standard. 4.2 Load/deflection characteristics The rubber shall have loa
43、d/deflection characteristics lying within prescribed limits. These characteristics shall be indicated in terms of either a given shear modulus(4.2.1) or a given hardness(4.2.2). Irrespective of the method used, the hardness of the rubber shall lie within the overall range of45IRHD to75IRHD. Because
44、the correlation between hardness and shear modulus is inexact, only hardness or shear modulus shall be specified, but not both. NOTE 3Shear modulus is one of the properties determining the load/deflection characteristics of the finished bearing. The customer therefore may require bearings which have
45、 been designed using a rubber of specific shear modulus or require bearings of specific stiffness. For many purposes, however, the supply of a rubber of a given hardness is often sufficient. For a given type of rubber, it is possible to establish an approximate relationship between hardness and shea
46、r modulus, but a close agreement independent of compounding variations should not be assumed. The following correlation at room temperature for chloroprene rubber (CR) and natural rubber (NR) isgiven for guidance purposes. It is not necessarily valid for other types of rubber. 4.2.1 Shear modulus If
47、 shear modulus is requested, the rubber shall be supplied to a shear modulus specified by the customer. For quality control purposes, the shear modulus tolerance shall meet the requirements given in Table 3. 4.2.2 Hardness If hardness is requested, the rubber shall be supplied to a nominal hardness
48、of50,60 or70 IRHD. The hardness tolerance shall meet the requirements given in Table 1. 4.3 Environmental resistance The rubber shall have adequate weathering resistance(4.3.1) and shall remain serviceable over the range of temperatures to which the bearing is exposed(4.3.2). 4.3.1 Ozone resistance
49、The rubber shall be suitably compounded against the effects of ozone. Alternative test severities are specified in6.1.3 in recognition of the wide global variations in ambient ozone concentration. Hardness, IRHD 50 60 70 Shear modulus, MPa 0,65 1,0 1,35BSISO6446:1994 BSI 12-1999 3 4.3.2 Low-temperature resistance Five grades related to low-temperature resistance are defined. The grades and typical operating-temperature conditions for each are asfollows: Grade1: Temperatures down to+5 C. Grade2: Sub-zero temperatures occ
