BS 7533-8-2003 Pavements constructed with clay natural stone or concrete pavers - Guide for the structural design of lightly trafficked pavements of precast concrete flags and natu.pdf

1、BRITISH STANDARD BS 7533-8:2003 Pavements constructed with clay, natural stone, or concrete pavers Part 8: Guide for the structural design of lightly trafficked pavements of precast concrete flags and natural stone flags ICS 93.080.20 BS 7533-8:2003 This British Standard was published under the auth

2、ority of the Standards Policy and Strategy Committee on 19 March 2003 BSI 19 March 2003 The following BSI references relate to the work on this British Standard: Committee reference B/507 Draft for comment 01/102974 DC ISBN 0 580 41295 4 Committees responsible for this British Standard The preparati

3、on of this British Standard was entrusted to Technical Committee B/507, Paving units and kerbs, upon which the following bodies were represented: Brick Development Association British Cement Association British Ceramic Research Ltd. British Precast Concrete Federation Ltd. Concrete Society County Su

4、rveyors Society Department of the Environment, Transport and the Regions (Highways Agency) Institution of Civil Engineers Interlay (Association of Block Paving) Interpave (Concrete Block Paving Association) Landscape Institute Society of Chemical Industry Stone Federation Transport Research Laborato

5、ry The following organizations were also represented in the drafting of the standard, through subcommittees B/507/1 and B/507/2: British Slate Association British Civil Engineering Manufacturers Association Department of the Environment, Transport and the Regions (Building Research Establishment) Mi

6、nistry of Defence Amendments issued since publication Amd. No. Date CommentsBS 7533-8:2003 BSI 19 March 2003 i Contents 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 4M a t e r i a l s 2 5G e n e r a l d e s

7、i g n 2 6D e s i g n 2 Annex A (informative) Design example 7 Annex B (normative) Overlay pavements 10 Figure 1 Graph: base design for paving flag overstressing 4 Figure 2 Graph: base design for subgrade overstressing (400 mm 400 mm and 450 mm 450 mm paving units) 5 Figure 3 Graph: base design for s

8、ubgrade overstressing (300 mm 300 mm paving units) 6 Figure A.1 Graph: base design for paving flag overstressing Design example 8 Figure A.2 Graph: base design for subgrade overstressing (400 mm 400 mm and 450 mm 450 mm paving units) Design example 9 Table 1 Estimated equilibrium CBR values for desi

9、gn 2 Table 2 Number of commercial vehicles 3 Table 3 Standard axle conversion 3 Table B.1 Condition Factor CF1 10 Table B.2 Condition Factor CF2 10BS 7533-8:2003 ii BSI 19 March 2003 Foreword This part of BS 7533 has been prepared by Technical Committee B/507. BS 7533 will be published in the follow

10、ing 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 concrete paving blocks. Part 3: Code of practice for

11、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 than structural aspects). Part 6: Code of practice for layin

12、g 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: Guide for the structural design of lightly trafficked pavements of precast concrete flags and natural stone slabs. Part 9 1) : Code of practice for la

13、ying clay pavers. NOTE This part of BS 7533 is based largely on research work commissioned by Interpave, the precast concrete paving and kerb association. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compl

14、iance with a British Standard does not of itself confer immunity from legal obligations. 1) In preparation. 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. The BSI copyright notice displayed in this

15、document indicates when the document was last issued.BS 7533-8:2003 BSI 19 March 2003 1 1 Scope This British Standard gives guidance on the design of flexible pavements surfaced with precast concrete flags or natural stone slabs and laid on a 30 mm sand laying course with sand filled narrow joints,

16、in accordance with BS 7533-4. It applies to pavements subject to occasional overrun by no more than 15 commercial vehicles per day at speeds not exceeding 50 kph (30 mph). The fundamental objective is the assessment of the thickness of base material to be used beneath precast concrete flags and natu

17、ral stone slabs to ensure that the allowable stresses in the paving units and the subgrade are not exceeded. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references,

18、 the latest edition of the referenced document (including any amendments) applies. BS 6100-2.4.1:1992, Glossary of building and civil engineering terms Part 2: Civil engineering Section 4.1: Highway, railway and airport engineering Highway engineering. BS 7263-1:2001, Precast concrete flags, kerbs,

19、channels, edgings and quadrants Part 1: Precast, unreinforced concrete paving flags and complementary fittings Requirements and test methods. BS 7533-1, Pavements constructed with clay, natural stone or concrete pavers Part 1: Guide for the structural design of heavy duty pavements constructed of cl

20、ay pavers or precast concrete paving blocks. BS 7533-4:1998, Pavements constructed with clay, natural stone or concrete pavers Code of practice for the construction of pavements of precast concrete flags or natural stone slabs. BS EN 1341:2000, Slabs of natural stone for external paving Requirements

21、 and test methods. Department of Transport, Specification for Highway Works, 1986 edition. Department for Transport, Local Government and the Regions, London: The Stationery Office. 3 Terms and definitions For the purposes of this part of BS 7533 the terms and definitions given in BS 6100-2.4.1:1992

22、 and the following apply. 3.1 paving unit precast concrete flag of designation E, F or G, conforming to BS 7263-1:2001 (excluding 50 mm thick), with a class B2 bending stress; or a natural stone flag of square plan, not exceeding 450 mm 450 mm, conforming to BS EN 1341:2000 with a class 5 breaking l

23、oad 3.2 laying course layer of material on which paving units are bedded 3.3 subgrade upper part of the soil, natural or constructed, that supports the loads transmitted by the overlying pavement 3.4 pavement any paved area subject to pedestrian and/or vehicular traffic 3.5 base material layer of ma

24、terial, either Type 1 or Type 2 granular material or cement bound material, as specified in the Specification for Highway Works (see Clause 2), placed immediately above the subgradeBS 7533-8:2003 2 BSI 19 March 2003 3.6 cement bound material (CBM) granular material to which cement has been added 3.7

25、 standard axle axle carrying a load of 8 200 kg 3.8 cumulative traffic number of standard axles a pavement is designed to carry over its lifetime 3.9 commercial vehicle vehicle having an unladen weight exceeding 1.5 t 4 Materials Precast concrete flags should conform to BS 7263-1. Natural stone slab

26、s should conform to BS EN 1341. NOTE Marble slabs are unsuitable for external trafficked pavements in the U.K. 5 General design The design of the pavement should be based on the following assumptions regarding the construction. a) The construction generally conforms to BS 7533-4. b) The minimum thic

27、kness of any base material is 100 mm. c) The laying course sand conforms to BS 7533-4:1998, 6.9.1. d) The joints are filled with sand conforming to BS 7533-4:1998, 6.9.1. Sedimentary stones should be laid on their bedding plane, where this is apparent. 6 Design NOTE See Annex A for an example of des

28、ign. 6.1 Subgrade assessment If laboratory CBR values are not available then Table 1 may be used as a guide to the equilibrium CBR values. Table 1 Estimated equilibrium CBR values for design 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

29、10 5 Sand poorly graded 20 Sand well graded 40 Sandy gravel 60BS 7533-8:2003 BSI 19 March 2003 3 6.2 Evaluation of traffic Firstly the total number of commercial vehicles using an area during the design life of the pavement should be obtained. In the absence of more reliable information, an estimate

30、 may be made based on Table 2. Table 2 Number of commercial vehicles For pavements subject to normal vehicle loads, it may be assumed that each commercial vehicle per day is equivalent to one standard axle per day. Otherwise, where the actual traffic mix is known, Table 3 should be used to determine

31、 the standard axles per day. Table 3 Standard axle conversion 6.3 Determination of construction thickness NOTE For overlay pavements see Annex B. The following information should be obtained for design. a) The type and number of commercial vehicles per day. b) The required design life NOTE 20 years

32、is commonly used. c) The type of base. d) The paving unit size and thickness. 6.4 Design procedure 6.4.1 General It is essential that the required thickness of the base is determined by the use of the graphs in Figure 1, Figure 2 and Figure 3, to prevent overstressing of the paving unit or the subgr

33、ade. The thicker of the two values should be adopted. 6.4.2 Paving unit stress limiting method To determine the base thickness required to prevent overstressing of the paving unit, the cumulative standard axles determined in 6.2 should be plotted on the “number of standard axles” axis on Figure 1. A

34、 vertical line should then be projected upwards to intersect the selected base material curve and a horizontal line projected from this intersection to cut the “base thickness axis”. 6.4.3 Subgrade stress limiting method To determine the base thickness required to prevent overstressing of the subgra

35、de, the cumulative standard axles determined in 6.2 should be plotted on the “number of standard axles” axis on Figure 2 or Figure 3 as appropriate. A vertical line should then be projected upwards to intersect the base CBR curve and a horizontal line projected from this intersection to cut the “bas

36、e type axis”, and then vertically downward to indicate the required base thickness. 6.4.4 Base thickness The thicker of the two base thicknesses evaluated in 6.4.2 and 6.4.3 should be adopted for the design. Location Commercial vehicles per day Residential areas 1 Small shopping areas 5 Large shoppi

37、ng areas 10 Precincts and pedestrianized areas 15 Vehicle type Number of standard axles per commercial vehicle 2 axle rigid 0.34 3 axle rigid 1.70 4 axle 2.60BS 7533-8:2003 4 BSI 19 March 2003 Figure 1 Graph: base design for paving flag overstressingBS 7533-8:2003 BSI 19 March 2003 5 Figure 2 Graph:

38、 base design for subgrade overstressing (400 mm 400 mm and 450 mm 450 mm paving units)BS 7533-8:2003 6 BSI 19 March 2003 Figure 3 Graph: base design for subgrade overstressing (300 mm 300 mm paving units)BS 7533-8:2003 BSI 19 March 2003 7 Annex A (informative) Design example A pavement in a shopping

39、 centre is to be constructed using 400 mm 400 mm 65 mm paving units. It is estimated that five days per week there will be 10 commercial vehicles per day servicing the shops. It is anticipated that this daily traffic will comprise six number 2-axle rigid, three number 3-axle rigid, and one number 4-

40、axle, vehicles. Servicing will take place 50 weeks a year over a 20 year design life. A site investigation indicates the CBR of the subgrade is 3 % and the base material to be used is Type 1. a) The conversion factors in Table 3 can be used to determine the number of standard axles: b) The total num

41、ber of standard axles in the 20 year design life: c) From the graph of Figure A.1: Base thickness = 165 mm Type 1 d) From the graph of Figure A.2: Base thickness = 240 mm Type 1 e) The greater thickness from steps c) and d) is adopted for design purposes, i.e.: Required thickness of Type 1 = 240 mm

42、6 number 2-axle rigid at 0.34 = 2.04 3 number 3-axle rigid at 1.70 = 5.10 1 number 4-axle vehicle at 2.60 = 2.60 =9.74 =5 50 20 9.74 = 48 700 Say 50 000BS 7533-8:2003 8 BSI 19 March 2003 Figure A.1 Graph: base design for paving flag overstressing Design exampleBS 7533-8:2003 BSI 19 March 2003 9 Figu

43、re A.2 Graph: base design for subgrade overstressing (400 mm 400 mm and 450 mm 450 mm paving units) Design exampleBS 7533-8:2003 10 BSI 19 March 2003 Annex B (normative) Overlay pavements In pedestrian schemes, paving units are often used as an overlay to existing bituminous pavements. If vehicles a

44、re to use the area, then it is first necessary to estimate the residual life of the existing pavement to determine the overlay depth needed to give the required design life. The existing pavement should be inspected for surface cracking and rutting and an assessment on the residual life should be ma

45、de. By using one or both of the factors given in Table B.1 and Table B.2, the equivalent thickness can be calculated. Table B.1 Condition Factor CF1 Table B.2 Condition Factor CF2 The existing construction thickness should be multiplied by the Condition Factors CF1 and CF2, where applicable. This eq

46、uivalence value should then be compared with the base design thickness, excluding flag and laying course, obtained by the design method given in this standard. If the base design thickness exceeds the equivalence value of the existing pavement then the new design is adequate. If the base design thic

47、kness is less than the equivalence value of the existing pavement then the base thickness should be increased. Where the new base material is different from the existing base material both base thicknesses should be converted to an equivalent thickness of DBM (dense bitumen macadam), using the proce

48、dure outlined in BS 7533-1. Condition of material CF1 As new 1.0 Some cracking 0.8 Substantial cracking 0.5 Fully cracked, crazed and spalling 0.2 Degree of localized rutting or settlement mm CF2 0 to 10 1.0 11 to 20 0.9 21 to 40 0.6 40 plus 0.3blankBS 7533-8:2003 BSI 389 Chiswick High Road London W

49、4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest ame