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1、BRITISH STANDARD BS 7533:1992 Incorporating Amendment No. 1 Guide for Structural design of pavements constructed with clay or concrete block pavers Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:55:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7533:1992 T
2、his British Standard, having been prepared under the direction of the Technical Sector Board for Building and Civil Engineering (B/-), was published under the authority of the Standards Board and comes into effect on 31 January 1992 BSI 01-1999 The following BSI references relate to the work on this
3、 standard: Committee reference B/507 Draft for comment 90/11700 DC ISBN 0 580 20244 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Technical Sector Board for Building and Civil Engineering (B/-) to Technical Committee B/507, upon whic
4、h the following bodies were represented: Brick Development Association British Aggregate Construction Materials Industries British Cement Association British Ceramic Research Ltd. British Precast Concrete Federation Ltd. Cementitious Slag Makers Association County Surveyors Society Department of Tra
5、nsport Institution of Highways and Transportation Interpave (the Concrete Block Paving Association) Landscape Institute National Paving and Kerb Association Society of Chemical Industry Stone Federation Amendments issued since publication Amd. No.DateComments 7644May 1993Indicated by a sideline in t
6、he margin Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:55:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7533:1992 BSI 01-1999i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 General design criteria 1 4 Ne
7、w pavement design 2 5 Pavement course specification 5 6 Pavement overlay design 7 Appendix A Specification for Highway Works clauses 10 Appendix B Example of the use of the component overlay design method 10 Figure 1 Pavement cross section 5 Figure 2 New pavement design procedure 6 Table 1 Equilibri
8、um suction index CBR values 3 Table 2 Relationship between commercial vehicles per day and the number of standard axles for design lives of 20 years and 40 years at growth rates of 0 % and 2 % per annum 3 Table 3 Specification for Highway Works clauses 5 Table 4 Material conversion factors for evalu
9、ating highway pavement materials 7 Table 5 Equivalent thickness of pavers 8 Table 6 Condition factor CF1 8 Table 7 Condition factor CF2 8 Table 8 Existing pavement construction 10 Table 9 Structural DBM equivalence 10 Table 10 Paver overlay 10 Publication(s) referred toInside back cover Licensed Cop
10、y: London South Bank University, London South Bank University, Fri Dec 08 14:55:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7533:1992 ii BSI 01-1999 Foreword The design of pavements using clay or concrete block pavers is hampered by the lack of data on the performance of highway pavements in th
11、e United Kingdom with this type of surfacing. The information given in this standard is the current state of the art. Few of the pavements laid to-date have reached the end of their design life, however, premature failures have been uncommon. Current UK experience is based on the application of clay
12、 and concrete block pavers on roads with traffic speeds up to 30 miles/h (50 km/h). Research has indicated that block paving behaves in a similar manner to conventional flexible pavement construction materials. This similarity has been used as a basis for this standard and has been proven in several
13、 design projects worldwide over a period of approximately 15 years. The Technical Committee has studied the performance of pavements in the UK, looked at overseas practice and the extensive work carried out in laboratories worldwide and at the Transport and Road Research Laboratory (TRRL). The resul
14、ts of these studies give no unequivocal evidence on the relative structural performance of clay and concrete block pavers compared with more traditional pavement construction materials. A surface deflection overlay procedure and a component overlay design method are recommended for determining wheth
15、er an existing pavement can be overlain with clay or concrete block pavers. The surface deflection method is based upon the method described in TRRL Reports 833, 834 and 8351). The component overlay method was first introduced by The Asphalt Institute, Maryland, USA and has been used in the British
16、Ports Federation heavy duty pavement design manual and in many other pavement design procedures. The design recommendations have been based on the principle that the roadbase will remain intact for the design life which is based on traffic damaging power. During the design life, maintenance of the s
17、urface may be required in the form of lifting and relaying the pavers on sand to correct for surface deformations exceeding current design tolerances. This is more likely where there is channelized traffic. Designers should note that this is a structural design guide to provide guidance on the sub-b
18、ase and roadbase thicknesses beneath the pavers, necessary for the anticipated traffic. Surface characteristics such as skid resistance, surface irregularity, ride quality and noise are not considered in this standard. The agreement of the appropriate highway authority is required before any type of
19、 clay or concrete block paver can be used on a highway which is to be adopted by that authority. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard doe
20、s not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. T
21、his will be indicated in the amendment table on the inside front cover. 1) Available from TRRL, Wokingham Road, Crowthorne, Berkshire RG 11 6AU. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:55:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7533:1992 BSI
22、01-19991 1 Scope This British Standard provides guidance on the design of pavements surfaced with clay or concrete block pavers manufactured and laid in accordance with BS 6677 and BS 6717. It sets out the design procedures for pavements constructed with clay or concrete block pavers. It applies to
23、all pavements subjected to the usual road spectrum of axle loads up to 18 000 kg and trafficked by up to 12 000 000 cumulative standard axles, including both highway pavements and industrial pavements where the traffic is similar in character to highway vehicles. It specifically excludes very heavy
24、duty pavements such as those in ports. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard, the definitions given in BS 6100 apply, together with the following. 2.1 paver either clay pavers or co
25、ncrete block pavers NOTEClay pavers should comply with BS 6677-1 and concrete block pavers should comply with BS 6717-1. 2.2 laying course (bedding course) layer of material on which pavers are bedded 2.3 subgrade upper part of the soil, natural or constructed, that supports the loads transmitted by
26、 the overlaying road structure 2.4 subgrade improvement layer (capping layer) layer of granular or treated material at the top of the subgrade to provide an improved foundation for the pavement 2.5 sub-base one or more layers of material placed immediately above the subgrade 2.6 roadbase one or more
27、 layers of material placed above the sub-base that constitute the main structural elements of a flexible or a composite pavement 2.7 cement bound material (CBM) material to which cement has been added. The material is compacted to form a roadbase 2.8 stabilized material material to which cement, bit
28、umen or other binding material has been added 2.9 channelized traffic traffic where the vehicle track width and the traffic lane width are virtually the same NOTENormal lane widths in a highway do not constitute channelized traffic. 2.10 dynamic loading the spectrum of loads normally occurring on hi
29、ghway pavements at vehicle speeds exceeding 30 miles/h (50 km/h) 2.11 standard axle an axle carrying a load of 8 200 kg (18 000 lb) 2.12 cumulative traffic the number of standard axles a pavement is designed to carry, measured in million standard axles (msa) 2.13 commercial vehicles commercial vehic
30、les having an unladen weight exceeding 1.5 t 3 General design criteria 3.1 Basis of design The design of new pavements is based upon the method given in TRRL Report 1132 The structural design of bituminous roads. In the case of overlay design, either a surface deflection method or the component over
31、lay method, is used according to the type of pavement to be overlain. 3.2 Special cases The design method described in clause 4 can be applied directly to the majority of pavements. However in some cases, unusual or particularly onerous loading effects or other conditions will need to be taken into
32、account, e.g. the following. a) Where channelized traffic is expected, the traffic figures should be multiplied by three before carrying out the design, to allow for the increase in the concentrated application of loads at a particular point on the pavement. Normal lane widths in a highway do not ge
33、nerally constitute channelized traffic but channelized traffic can develop on any road, e.g. on steep hills or approaches to traffic signals. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:55:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7533:1992 2 BSI 0
34、1-1999 b) Where speeds in excess of 30 miles/h are expected, the cumulative traffic should be multiplied by two before carrying out the design to allow for dynamic loading effects. c) Pavements constructed over frost-susceptible soils should have an overall thickness of non frost-susceptible materia
35、l of not less than 450 mm. d) Materials, whose successful performance is dependent upon compaction being undertaken at critical moisture contents, should only be used when engineering supervision can ensure that a stable construction can be achieved. NOTESome materials given in clause 804 of the Dep
36、artment of Transport Specification for Highway Works2) (see Appendix A) fall into this category. 4 New pavement design 4.1 Subgrade assessment The design California Bearing Ratio (CBR) should be obtained either by direct measurement, or by measurement of the plasticity index of the subgrade material
37、. In the case of direct CBR measurement, the method described in clause 7 of BS 1377-4:1990 should be used. In situations where it is possible that the subgrade will become saturated during part or all of the life of the pavement, the method employing the soaking procedure should be used. Alternativ
38、ely, equilibrium suction index CBR values should be used. In the case of fine grained soils, the equilibrium suction index CBR can be determined from a knowledge of the plasticity index as detailed in Table 1. Effective subgrade drainage can have a significant effect on long-term CBR values, and nee
39、ds consideration during the design procedure. Filter drains set at the appropriate level and discharging to a satisfactory outfall or main drainage system have been found to perform satisfactorily. On sites where the CBR varies from place to place, the lowest recorded values should be used or, alter
40、natively, appropriate designs should be provided for different parts of the site using the lowest CBR recorded in each part. It may be possible to remove soft spots and therefore ignore those low CBR values which relate to the removed material. Consideration should be given to using portable CBR mea
41、suring apparatus, for example the MEXIprobe has been found to give sufficiently accurate results on fine-grained soils. It is often the case that a large number of CBR measurements undertaken with this type of apparatus is preferable to a relatively few measurement undertaken with the full scale in
42、situ CBR measuring apparatus. Care should be exercised in the interpretation of site investigation data. In the case of soils whose strength is a function of their moisture content the in-service strength may be much lower than the recorded values. Care should also be exercised in using CBR values m
43、easured in summer as artificially high figures may be obtained due to the dryness of the soil. Particular care should be exercised with soils having CBRs of 3 % or less. It should be recognized that BS 1377 requires that CBRs are quoted to the nearest whole figure, so that for very low CBRs the reco
44、rded value will be an approximation. The surface of the subgrade material should be prepared according to clause 616 of the Department of Transport Specification for Highway Works. In the case of silty clays the use of a vibrating roller may fluidize the material rather than compact it. In such case
45、s a deadweight roller is preferred. Detailed preparation of the subgrade shall be in accordance with the recommendations in BS 6717-3, or BS 6677-3, as appropriate. 4.2 Design life Design has to take into account the cumulative amount of traffic which the pavement has to carry, measured either in te
46、rms of the number of commercial vehicles per day (cv/d), or alternatively, the number of standard axles. Table 2 shows the relationship between commercial vehicles per day and million standard axles for design lives of 20 years and 40 years, in each case with zero growth and with growth in traffic o
47、f 2 % per annum. 2) Available from HMSO, 49 High Holborn, London WC1 for personal callers or by post from HMSO, PO Box 276, London SW8 5DT. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:55:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7533:1992 BSI 01-19
48、993 Table 1 Equilibrium suction index CBR values Table 2 Relationship between commercial vehicles per day and the number of standard axles for design lives of 20 years and 40 years at growth rates of 0 % and 2 % per annum It is suggested that a 20 year design life will be generally applicable unless
49、 access for possible maintenance of the roadbase is likely to be difficult or expensive. Where the pavement serves a finite area, zero growth in traffic is likely to be applicable, otherwise 2 % growth is recommended. If calculated growth figures are available these should be used to ascertain the number of standard axles. It may be necessary to reset the pavers during the life of a pavement if the rut depth exceeds 10 mm. This may be a result of displacement of the laying course sand and is not necessarily an indication of pavement failure. An inspect