1、BRITISH STANDARD BS 7533-2:2001 Incorporating Corrigendum No. 1 Pavements constructed with clay, natural stone or concrete pavers Part 2: Guide for the structural design of lightly trafficked pavements constructed of clay pavers or precast concrete paving blocks ICS 93.080.20 NO COPYING WITHOUT BSI
2、PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS 7533-2:2001 The British Standard, having been prepared under the direction of the Sector Committee for Building and Civil Engineering, was published under the authority of the Standards Board and comes into effect on 15 May 2001 BSI 06-2001 The follo
3、wing BSI references relate to the work on this standard: Committee reference B/507 ISBN 0 580 33259 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee B/507, Paving units and kerbs, upon which the following bodies were rep
4、resented: Brick Development Association British Cement Association British Ceramic Research Ltd. British Precast Concrete Federation Ltd. Concrete Society County Surveyors Society Department of the Environment, Transport and the Regions (Highways Agency) Institution of Civil Engineers Interlay (Asso
5、ciation of Block Paving) Interpave (Concrete Block Paving Association) Landscape Institute Society of Chemical Industry Stone Federation Transport Research Laboratory Amendments issued since publication Amd. No. Date Comments 13217 June 2001 Correction of error in titleBS 7533-2:2001 BSI 06-2001 i C
6、ontents Page Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3T e r m s a n d d e f i n i t i o n s 1 4 General design criteria 3 5 Determination of construction thickness 5 6 Preparation and construction 6 7 Overlay design 6 Annex A (informative) Identifi
7、cation of materials and CBR values using a simple field test 7 Bibliography 8 Figure 1 Typical cross-section of pavement 2 Table 1 CBR values for different materials 4 Table 2 Typical application 4 Table 3 Standard axles per commercial vehicle 5 Table 4 Construction thickness 6 Table 5 Alternative c
8、onstruction thickness (in millimetres) for category IIIa sites only 6 Table A.1 Identification of materials and CBR values using a simple field test 7BS 7533-2:2001 ii BSI 06-2001 Foreword This part of BS 7533 has been prepared by Technical Committee B/507. It supersedes BS 6677-2:1986, which is wit
9、hdrawn. BS 7533 will be published in the following parts: Part 1: Guide for the structural design of heavy duty pavements constructed of clay pavers or precast concrete paving blocks; Part 2: Guide for the structural design of lightly trafficked pavements constructed of clay pavers or precast concre
10、te paving blocks; Part 3: Code of practice for laying precast concrete paving blocks and clay pavers for flexible pavements; Part 4: Code of practice for the construction of pavements of precast concrete flags or natural stone slabs; Part 5 1) : Guide for the design of pavements (other structural as
11、pects); Part 6: Code of practice for laying natural stone, precast concrete and clay kerb units; Part 7 1) : Code of practice for the construction of pavements of natural stone setts; Part 8 1) : Guide for the structural design of lightly trafficked pavements of precast concrete flags and natural st
12、one slabs; Part 9 1) : Code of practice for laying clay pavers. Annex A is informative. 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 does not of
13、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 8, an inside back cover and a back cover. The BSI copyright notice displayed throughout this document indicates when the document was last issued.
14、1) In preparation.BS 7533-2:2001 BSI 06-2001 1 1 Scope This British Standard provides guidance on the design of lightly trafficked pavements surfaced with clay or concrete block pavers manufactured in accordance with BS 6677-1 or BS 6717-1 respectively and laid in accordance with BS 7533-3. It appli
15、es to all paved areas subjected to the usual road spectrum of axle loads up to 11 000 kg and trafficked by up to 0.5 million cumulative standard axles (msa), e.g. culs-de-sac, driveways, car parks, precincts, lightly trafficked roads and paved areas. 2 Normative references The following normative do
16、cuments contain provisions which, through reference in this text, constitute provisions of this part of this British Standard. For dated references, subsequent amendments to, or revisions of any of these publications do not apply. For undated references, the latest edition of the publication referre
17、d to applies. BS 4987-1, Coated macadam (asphalt concrete) for roads and other paved areas Part 1: Specification for constituent materials and for mixtures. BS 6677-1, Clay and calcium silicate pavers for flexible pavements Part 1: Specification for pavers. BS 6717-1, Precast concrete paving blocks
18、Part 1: Specification for paving blocks. BS 7533-1, Pavements constructed with clay, natural stone or concrete pavers Part 1: Guide for structural design of pavements constructed of clay or concrete block pavers. BS 7533-3, Pavements constructed with clay, natural stone or concrete pavers Part 3: Co
19、de of practice for laying precast concrete paving blocks and clay pavers for flexible pavements. 3 Terms and definitions For the purposes of this part of BS 7533 the following terms and definitions apply. 3.1 paver either a clay paver or a concrete block paver 3.2 laying course layer of material on
20、which pavers are bedded 3.3 subgrade upper part of the soil, natural or constructed, that supports the loads transmitted by the overlaying road structure (see Figure 1) 3.4 pavement any paved area subject to pedestrian and/or vehicular traffic 3.5 sub-base one or more layers of material placed immed
21、iately above the subgrade (see Figure 1) 3.6 roadbase one or more layers of material placed above the sub-base that constitute the main structural element of a pavement NOTE The roadbase can be a bituminous material and/or cement bound material. 3.7 cement bound material (CBM) granular material to w
22、hich cement has been added BS 7533-2:2001 2 BSI 06-2001 3.8 channelized traffic traffic where the vehicle track width and the traffic lane width are virtually the same, e.g. narrow entrances such as gates NOTE Normal lane widths in a highway do not constitute channelized traffic. 3.9 standard axle a
23、xle carrying a load of 8 200 kg 3.10 cumulative traffic number of standard axles a pavement is designed to carry, measured in million standard axles (msa) 3.11 commercial vehicle vehicle having an unladen weight exceeding 1 5 t 3.12 lightly trafficked pavement pavement which receives a limited numbe
24、r of heavy vehicles Figure 1 Typical cross-section of pavement Laying Course Roadbase Sub-base Surface SubgradeBS 7533-2:2001 BSI 06-2001 3 4 General design criteria 4.1 Subgrade assessment The design is based upon an assessment of the subgrade bearing strength described as the CBR (California Beari
25、ng Ratio). The weaker the subgrade, the stronger the pavement is required to be. The design CBR should be obtained by measurement of the plasticity index or material description of the subgrade and by use of Table 1. For category IV only (see Table 2), a guide to subgrade strength may be estimated b
26、y using a simple field test given in Annex A (see also Table 1). This is intended to be an indicator of the strength of this layer. Tests are carried out after the initial compaction of the trimmed ground. 4.2 Evaluation of traffic The number of commercial vehicles using the area should first be obt
27、ained. Table 2 gives the categories of classification for the different applications. For category I and II vehicles, usage and the relationship of standard axles should be estimated in accordance with Table 3. As the type of commercial vehicles using the pavement will be mixed the probable daily am
28、ount of each type of vehicle should be determined in order to estimate the total number of standard axles per day. Design should take into account the cumulative traffic which the pavement has to carry, measured either in terms of the number of commercial vehicles per day (cv/d) or the number of sta
29、ndard axles. A 20 year design life should be generally applicable unless access for possible maintenance of the roadbase is likely to be difficult or expensive in which case a longer design life may be advisable. Where the pavement serves a finite area, zero growth in traffic is likely to be applica
30、ble. 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. This may be a result of displacement of the laying course sand and is not necessarily an indication of pavement failu
31、re.BS 7533-2:2001 4 BSI 06-2001 Table 1 CBR values for different materials Table 2 Typical application Type of soil Plasticity index Estimated CBR Heavy clay 70 2 60 2 50 2 40 3 Silty clay 30 4 Sandy clay 20 5 10 5 Silt 1 Sand poorly graded 20 (7 a ) Sand well graded 40 (10 a ) Sandy gravel 60 (15 a
32、 ) NOTE 1 Table 1 is intended for use where the water table is 300 mm or more below formation level. In other conditions, specialist advice should be sought. NOTE 2 Effective subgrade drainage can have a significant effect on long-term CBR values and should be considered during the design procedure.
33、 Filter drains set at the appropriate level and discharging to a satisfactory outfall or main drainage system have been found to perform satisfactorily. NOTE 3 On sites where the CBR varies from place to place, the lowest recorded values should be used or appropriate designs should be provided for d
34、ifferent 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. NOTE 4 Soft spots should be removed and replaced with suitable material. NOTE 5 Care should be exercised in t
35、he 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 measured in summer as artificially high figures may be obtai
36、ned due to dryness of the soil. NOTE 6 Particular care should be exercised with subgrades having measured CBRs of 3 % or less. a The bracketed figures should be considered if these materials are likely to become saturated in service. Category Maximum trafficking (msa) cv/d Typical applications I 0.5
37、 Use BS 7533-1 II 0.5 5 Adopted highways and other roads less than 0.5 msa, e.g. culs-de-sac, petrol station forecourts, pedestrianized areas subject to regular heavy trafficking 5 Car parks receiving occasional heavy traffic Footways regularly overridden by vehicular traffic IIIa 1 Pedestrianized a
38、reas receiving only occasional heavy traffic Footways overridden by occasional vehicular traffic IIIb Nil Car parks receiving no heavy traffic Footways likely to be overridden by no more than occasional vehicular traffic IV Private drives, paths, patio, hard landscaping Areas receiving pedestrian tr
39、affic only, e.g. school playgrounds NOTE 1 Access ways to commercial and business premises and public buildings should be placed either in category II or IIIa depending upon the estimate of the total commercial vehicle traffic likely to use the pavement. NOTE 2 In determining the site category, the
40、use of the surface of the pavement by any construction traffic should be assessed and used in traffic calculations.BS 7533-2:2001 BSI 06-2001 5 Table 3 Standard axles per commercial vehicle 4.3 Additional design factors The design method can be applied directly to the majority of applications. Howev
41、er, in some cases, such as those outlined in a) to b), unusual or particularly onerous loading effects or other conditions should be taken into account. a) Where relatively few standard axles are to be accommodated (less than 100 000) but where the loading is commonly applied by axle loads in excess
42、 of 7 000 kg, the pavement should be designed to withstand either 100 000 standard axles or three times the actual number of standard axles, whichever is the greater. b) Where channelized traffic on pavements in categories II and III (see Table 2) is expected, the traffic figures should be multiplie
43、d 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 generally constitute channelized traffic but channelized traffic can develop on any road, e.g. on steep hills or
44、 approaches to traffic signals, or entrances to parking areas, and can be induced by some traffic calming measures. If the application of this factor leads to traffic exceeding 0.5 msa, the design should be carried out in accordance with BS 7533-1. 4.4 Materials Materials whose successful performanc
45、e 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. Pavements in categories II and III (see Table 2) constructed over frost-susceptible soils should have an overall thick
46、ness of non frost-susceptible material of at least 450 mm. 5 Determination of construction thickness Having assessed the category of application (see Table 2) and the design CBR (see Table 1), the thickness of each pavement layer should be determined in accordance with Table 4 or Table 5. Vehicle ty
47、pe Conversion factor Buses and coaches 1.3 2 axle rigid 0.34 3 axle rigid 1.7 3 axle articulated 0.65 4 axle rigid 3.0 4 axle articulated 2.6 5 axles or more 3.5BS 7533-2:2001 6 BSI 06-2001 Table 4 Construction thickness Table 5 Alternative construction thickness (in millimetres) for category IIIa s
48、ites only 6 Preparation and construction Detailed preparation of the subgrade should be in accordance with the recommendations in BS 7533-3. Where bituminous roadbase is used, it should be 20 mm nominal size dense bitumen macadam (DBM) conforming to BS 4987-1 with 100 pen binder, laid in two layers.
49、 Where cement bound material (CBM) is used it should be either CBM 1A or CBM 2 with minimum individual 7 day compressive strength of 4.5 N/mm 2 . 7 Overlay design When an existing part of a worn pavement is to be overlain, the design should be undertaken using a component overlay design method in accordance with the recommendations in BS 7533-1. When existing flexible roads are to be overlain, the design should be undertaken using a deflection-based method in accordance with the rec
