1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI British Standards WB9423_BSI_StandardColCov_noK_AW:BSI FRONT COVERS 5/9/08 12:55 Page 1 PD 6703:2009 PUBLISHED DOCUMENT Structural bearings Guidance on the use of structural bearings This publicati
2、on is not to be regarded as a British Standard. PD 6703:2009 PUBLISHED DOCUMENT Publishing and copyright information The BSI copyright notice displayed in this document indicates when the document was last issued. BSI 2009 ISBN 978 0 580 60910 7 ICS 91.010.30 The following BSI reference relates to t
3、he work on this standard: Committee reference B/522 Publication history First published August 2009 Amendments issued since publication Date Text affected BSI 2009 i PD 6703:2009 PUBLISHED DOCUMENTContents Foreword ii 0 Introduction 1 1 Scope 1 2 Normative references 1 3 Terms and definitions 2 4 De
4、sign 2 5 Structural design considerations 4 6 Manufacture 6 7 Connections 11 8 Final assembly, clamping and presetting 13 9 Testing 14 10 Installation 19 11 Guidance on specification requirements 23 Annexes Annex A (normative) Bearing schedule 24 Bibliography 26 List of figures Figure 1 Load distrib
5、ution 4 Figure 2 Knuckle and leaf bearings 11 Figure 3 Typical bearing detail 20 List of tables Table 1 Thickness of austenitic steel sheet 7 Table 2 Chemical composition of applied layers in roller bearings 9 Table A.1 Typical bearing schedule 24 Summary of pages This document comprises a front cov
6、er, an inside front cover, pages i to ii, pages 1 to 26, an inside back cover and a back cover.ii BSI 2009 PD 6703:2009 PUBLISHED DOCUMENTForeword Publishing information This Published Document is published by BSI and came into effect on 31 August 2009. It was prepared by Technical Committee B/522,
7、Structural bearings. A list of organizations represented on this committee can be obtained on request to its secretary. Relationship with other publications This Published Document gives non-contradictory complementary information and additional guidance for use in the UK with BS EN 1337 (all parts)
8、, Structural bearings. Use of this document As a guide, this Published Document takes the form of guidance and recommendations. It should not be quoted as if it were a specification or a code of practice and claims of compliance cannot be made to it. Presentational conventions The provisions in this
9、 Published Document are presented in roman (i.e. upright) type. Its recommendations are expressed in sentences in which the principal auxiliary verb is “should”. Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.
10、 Contractual and legal considerations This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a Published Document cannot confer immunity from legal obligations. BSI 2009 1 PD 6703:2009 PUBLISHED DOCU
11、MENT0 Introduction When there is a need for guidance on a subject that is not covered by a European Standard, a country can choose to publish documents that contain non-contradictory complementary information that supports the European Standard. Where BS EN 1337 (all parts) refers to Eurocodes, the
12、Eurocodes (BS EN 1990 to BS EN 1999 inclusive) once published are deemed to include their UK National Annexes. Eurocodes apply to design, not to assessment. Where bearings are required to be replaced on an existing highway structure, their capacity may, with the agreement of the overseeing organizat
13、ion, be chosen to accommodate the assessment loading based on UK assessment standard BD 21, The assessment of highway bridges and structures 1, with appropriate partial factors of safety for loading. Attention is drawn to the requirements in BS EN 1337 (all parts) of CE marking under the Constructio
14、n Products Directive 2 enabling bearings to be legally placed on the market in any EU Member State. The requirements of BS EN 1337 (all parts) are augmented by BS EN 1993-2:2006, Annex A. The requirements of BS EN 1337-10 are to be implemented in accordance with the Highways Agencys Inspection manua
15、l for highway structures 3.1 Scope This Published Document contains non-contradictory complementary information and additional guidance for use in the UK with BS EN 1337 (all parts). It covers the design, testing and installation of structural bearings. In addition to those bearings covered by BS EN
16、 1337, this Published Document gives guidance on knuckle and leaf bearings and composite roller bearings. NOTE Annex A gives a typical bearing schedule, which has been extended from that given in BS EN 1337-1:2000, B.1, to cover UK practice.2 Normative references The following referenced documents a
17、re indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS 3416, Specification for bitumen-based coatings for cold application, suitable for
18、use in contact with potable water BS 5350-A1, Methods of test for adhesives Part A1: Adherend preparation BS 5400-2, Steel, concrete and composite bridges Part 2: Specification for loads BS 6949, Specification for bitumen-based coatings for cold application excluding use in contact with potable wate
19、r BS EN 1011-4, Welding Recommendations for welding of metallic materials Part 4: Arc welding of aluminium and aluminium alloys2 BSI 2009 PD 6703:2009 PUBLISHED DOCUMENT BS EN 1337-1:2000, Structural bearings Part 1: General design rules BS EN 1337-2:2004, Structural bearings Part 2: Sliding element
20、s BS EN 1337-3:2005, Structural bearings Part 3: Elastomeric bearings BS EN 1337-4, Structural bearings Part 4: Roller bearings BS EN 1337-5, Structural bearings Part 5: Pot bearings BS EN 1337-6, Structural bearings Part 6: Rocker bearings BS EN 1337-7, Structural bearings Part 7: Spherical and cyl
21、indrical PTFE bearings BS EN 1337-8, Structural bearings Part 8: Guide bearings and restraint bearings BS EN 1337-9, Structural bearings Part 9: Protection BS EN 1337-10, Structural bearings Part 10: Inspection and maintenance BS EN 1337-11:1997, Structural bearings Part 11: Transport, storage and i
22、nstallation BS EN 1464, Adhesives Determination of peel resistance of high-strength adhesive bonds Floating roller method BS EN 1600, Welding consumables Covered electrodes for manual metal arc welding of stainless and heat resisting steels Classification BS EN 1990:2002+A1:2005, Eurocode Basis of s
23、tructural design BS EN 1993-1-8, Eurocode 3: Design of steel structures Part 1-8: Design of joints BS EN 10204:2004, Metallic products Types of inspection documents3 Terms and definitions For the purposes of this Published Document, the terms and definitions given in BS EN 1337 (all parts) apply.4 D
24、esign4.1 Function To achieve the required degree of freedom in the function of a specific bearing, it might be necessary to combine the characteristics of different types of bearing, the resultant bearing as a whole providing the required movements and load resistance, e.g. a plane sliding bearing,
25、to allow translation, combined with a pot bearing, to provide for rotation.4.2 Durability Bearings should be detailed to exclude crevices, which allow moisture and dirt to be trapped. Skirts should be provided where specified by the overseeing organization, but the requirements of BS EN 1337-9 shoul
26、d not be modified as a result of skirt provision. BSI 2009 3 PD 6703:2009 PUBLISHED DOCUMENT4.3 Uplift If uplift can occur, bearings and their fixings should limit separation of the components to a value agreed with the overseeing organization and should resist the consequent forces. (See also BS EN
27、 1337-1:2000, A.1, second list point.)4.4 Loads and load effects4.4.1 Compatibility with an existing structure To ensure compatibility with an existing structure, replacement bearings should resist the loads and load effects specified in BS 5400-2 or the assessment-loading standard required by the o
28、verseeing organization and, where applicable, the effects of creep, shrinkage and pre-stress. Due allowance should be made for any eccentricities and specified dimensional tolerances in the application or distribution of loading. The design loads Q* on the bearings should be the nominal loads multip
29、lied by the appropriate values of g fL , all as specified in BS 5400-2. Design load effects S* at the serviceability limit state (SLS) and ultimate limit state (ULS) should be obtained by multiplying the effects of the design load Q* by g f3 . Values of g f3should be taken as 1.0 for the SLS and 1.1
30、 for the ULS unless otherwise stated.4.4.2 Restraints against translation Where restraints are provided on bearings to resist translational movements, they should be designed to resist either the design load effects or 5% of the permanent vertical design load on the bearing, whichever is the greater
31、. If restraint against translation (resistance to a horizontal force) is to be shared by several bearings, consideration should be given to: the effects of any clearance between working parts of the bearings and their guides during their service life; and the effects of the stiffness of the structur
32、e on the distribution of the resulting loads between the bearings. (See also BS EN 1337-1:2000, 7.1.4.) 4.4.3 Proportions of bearing plates The bearings should be so proportioned that concentrated loads are distributed to ensure that the permissible pressures on the adjacent bridge structure are not
33、 exceeded. The effective area for distributing the load may be taken as that between uninterrupted dispersal lines drawn from the bearing contact area at a maximum of 60 to the line of application of the bearing reaction (see Figure 1). Where the adjacent structure is likely to deform significantly
34、under load, the interaction of the structure and the bearing should be considered in the design of both. (See also BS EN 1337-2:2004, 6.9.)4 BSI 2009 PD 6703:2009 PUBLISHED DOCUMENTFigure 1 Load distribution Key 1 Uninterrupted dispersal lines 2 Contact area 3 Outer bearing or spreader plates 4 Effe
35、ctive area4.5 Tolerances NOTE Tolerances given in this document are suitable for bearings in normal use. In special circumstances of unusual loading or movement, different tolerances might be necessary. The tolerances in 10.3 should be drawn to the attention of fabricators providing plates. Toleranc
36、es for holes for fixing bolts should be related to the function of the bolts and the likely conditions prevailing at the time of installation of the bearings. As a guide, holes for fixing bolts or locating devices should be 1 mm from the positions shown on the design drawings. Their diameter should
37、be 2 mm larger than the nominal diameter of the bolt or locating key for fixing bearings to steel or precast concrete members, and 3 mm larger than the nominal diameter of bolt or shear key for replacement. For bolts or locating devices required to resist horizontal forces in shear, a close toleranc
38、e fit might be necessary. The effects of variation in dimensions within the permitted tolerances of the bearing, including those of spacer, spreader and taper plates above and below the bearings, should be considered in the design of bearings, their connections and the associated structure.5 Structu
39、ral design considerations5.1 Positioning of bearings The position of bearings should be such that they are able to operate as assumed in the design of the structure. Any secondary effects resulting from either eccentric loading or movement not truly along a major axis of the bearing should be taken
40、into account in the design of the bearing and surrounding structural elements. BSI 2009 5 PD 6703:2009 PUBLISHED DOCUMENT Bearings should be located so as to avoid the accumulation of dirt and debris likely to interfere with their performance and the structure detailed so that water is prevented fro
41、m reaching the bearings. Space should be provided around bearings to facilitate their inspection and maintenance. Consideration should be given in the design of the structure to the means of access to the bearings. 5.2 Use of different types of bearing When bearings with differing characteristics ar
42、e used on the same line of support, the resulting interactive effects should be considered both in the design of the bearings and the structure. NOTE Here, the “same line of support” is normally taken to mean transverse to the span direction.5.3 Provision for resetting and replacement of bearings (B
43、S EN 1337-1:2000, 7.6) Facilities for correcting the effects of any differential settlement and tilt should be provided in the design of the structure, e.g. by providing jacking points, unless the structure has been designed to accommodate such effects. A strategy for bearing replacement should be d
44、evised at the design stage of the structure, including any load restrictions required, and incorporated in the maintenance manual. The design should allow for live loading to be taken by the propped structure. In some instances it might be necessary to limit traffic during jacking but once the jacks
45、 are locked off, or supports installed, the bridge can be fully opened. The strategy should include the capacity and dimensions of jacks required and the provision, where necessary, of temporary guide and/or restraint bearings during bearing replacement. The structure should be capable of being lift
46、ed sufficiently to permit bearing replacement without the need to break out concrete to remove or replace holding down bolts. Provision should be made for jacking points of adequate size, strength, separation, accessibility and safety on the substructure and superstructure. Separation between jackin
47、g points should allow for the provision of sliding plates combined with the jacks, where required. Anchorage points for temporary guides and restraints should also be provided, as necessary. Jacking is not covered in BS EN 1337 (all parts). Typical aspects to be addressed include ensuring that: the
48、jacks exert acceptable pressures on horizontal surfaces; jacking loads are adequately distributed across the structure; deck joints are not damaged on lifting; temporary fixity is provided when replacing fixed or guided bearings; jacking loads and movements are monitored for structural safety; voids
49、 are eliminated from bearing re-bedding and no excessive deflection is registered when jacking back down on the bedded bearing; and holding down bolts are greased and nuts locked tight by approved means.6 BSI 2009 PD 6703:2009 PUBLISHED DOCUMENT When assessing the effects of jacking operations on the structure, the potential effects of a failure of a jack, or components, should be considered. Where multiple jacks are connected by a common component, e.g. a manifold or a hose,
