资源描述：
British Standard A single copy of this British Standard is licensed to Giorgio Cavalieri on March 05, 2001 This is an uncontrolled copy. Ensure use of the most current version of this standard by searching British Standards Online at bsonline.techindex.co.uk | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 6779-41999 ICS 93.040 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Highway parapets for bridges and other structures Part 4 Specification for parapets of reinforced and unreinforced masonry construction Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI This 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 Committee and comes into effect on 15 August 1999 BSI 08-1999 The following BSI references relate to the work on this standard Committee reference B/509/1 Draft for comment 97/108800 DC ISBN 0 580 28291 0 BS 6779-41999 Amendments issued since publication Amd. No.DateComments Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee B/509, Road equipment, to Subcommittee B/509/1, Road restraint systems, upon which the following bodies were represented Aluminium Federation Association of Consulting Engineers Association of County Councils Association of Safety Fencing Contractors British Cement Association British In-situ Concrete Paving Association British Precast Concrete Federation Ltd County Surveyors Society Department of Transport Highways Agency Institution of Civil Engineers Motor Industry Research Association National Fencing Training Authority Railtrack Royal Society for the Prevention of Accidents Transport Research Laboratory UK Steel Association Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI BS 6779-41999 BSI 08-1999i Contents Page Committees responsibleInside front cover Forewordiii Introduction1 1Scope1 2Normative references1 3Terms and definitions2 4Symbols3 5Designation of masonry vehicle parapets4 6Design4 6.1Levels of containment4 6.2Wind loading4 6.3Parapet heights4 6.4Front face and top face profile5 6.5Pilasters5 6.6Reinforced masonry parapets5 6.7Unreinforced masonry parapets10 7Materials and workmanship18 7.1General18 7.2Materials18 Annex A inative Risk assessment related to vehicle impacts on unreinforced masonry parapets20 Annex B inative Site specific levels of containment, assessment of existing parapets22 Annex C inative Reinforced masonry parapets dimensions and reinforcement of prototype25 Annex D inative Reinforced masonry parapets strain in vertical reinforcement25 Annex E normative Determination of the characteristic shear strength of masonry29 Annex F inative Background to the derivation of the containment charts for unreinforced masonry parapets33 Annex G inative Movement joints in unreinforced masonry parapets34 BibliographyInside back cover Figure 1 Reinforced masonry parapets, dimensions and profiles6 Figure 2 Containment chart, high mortar adhesion13 Figure 3 Containment chart, medium mortar adhesion14 Figure 4 Containment chart, low mortar adhesion15 Figure 5 Containment chart, drystone or mortared slate or similar parapets16 Figure 6 Drystone construction showing the basis for determining voids percentage17 Figure 7 Curved ends to parapet to prevent end on impact18 Figure A.1 Theoretical trajectory of a masonry block21 Figure B.1 Impacts with curved parapets23 Figure B.2 Relationship between divergent width and impact speed for impact angle of 208 from TRRL report no. 80123 Figure B.3 Chart relating divergent width and impact speed of errant vehicle24 Figure B.4 Chart relating divergent width and impact speed of errant vehicle for a curved layout25 Figure C.1 High containment bridge parapet26 Figure C.2 High containment bridge parapet reinforcement27 Figure D.1 Strain versus time in vertical reinforcement28 Figure E.1 Dimensions of shear test specimen30 Figure E.2 Loading of shear test specimen31 Figure E.3 Precompression load32 Figure E.4 Types of failure32 Figure E.5 Shear strength and angle of internal friction33 Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI BS 6779-41999 ii BSI 08-1999 Table 1 Designation of masonry vehicle parapets4 Table 2 Equivalent static nominal loads Qk for panel lengths L 2.0 m to 3.5 m inclusive5 Table 3 Values of gfl7 Table 4 Values of fcu, fy, fkand gm, ulitimate limit state7 Table 5 Criteria for unreinforced masonry parapets designed in accordance with Figure 211 Table 6 Criteria for unreinforced masonry parapets designed in accordance with Figure 311 Table 7 Shear transfer at movement joints12 Table A.1 Risk uation20 Table E.1 Dimensions and type of shear test specimens29 Table G.1 Suggested spacing of movement joints in unreinforced masonry parapets34 Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI BSI 08-1999iii BS 6779-41999 Foreword This part of BS 6779 has been prepared under the direction of Subcommittee B/509/1, Road restraint systems. Other parts already published in the series are Part 1 Specification for vehicle containment parapets of metal construction; Part 2 Specification for vehicle containment parapets of concrete construction; Part 3 Specification for vehicle containment parapets of combined metal and concrete construction. Anns A, B, C, D, F and G are inative. Annex E is normative. A British Standard does not purport to include all necessary 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, pages i to iv, pages 1 to 34, an inside back cover and a back cover. The BSI copyright notice displayed throughout this document indicates when the document was last issued. Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI ivblank Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI BSI 08-19991 BS 6779-41999 Introduction Reinforced or unreinforced masonry parapets are often used for economic reasons or where a masonry finish is required on the exposed surfaces of parapets. Reinforced masonry parapets contain steel reinforcement which is adequately anchored into the supporting structure. Unreinforced masonry parapets are built directly onto the supporting structure without any special provision for anchorage. As masonry parapets are of solid construction they provide effective pedestrian protection without modification, subject to satisfying the minimum height requirements specified in 6.3. The requirements in this standard, for both the reinforced and unreinforced masonry parapets, are based on the results of tests. The requirements for unreinforced masonry parapets are additionally based on mathematical modelling of vehicle impacts by computer which has been subsequently verified by full scale vehicle impact tests. In the case of unreinforced masonry parapets, individual blocks or sections of the masonry may be dislodged and mobilized by a vehicle impact. The tests and computer modelling have shown that most of this masonry will be propelled away from the highway, but some can come to rest on the highway in the immediate vicinity of the parapet. An assessment of the possible injury or damage risk from mobilized masonry can be used to determine the acceptability of the use of an unreinforced masonry parapet at a particular site. A suitable of risk assessment is described in annex A. Vehicle containment levels are related to defined vehicle impacts. Only normal and high containment levels are specified for reinforced masonry parapets. The low containment level described in part 1 of this standard, for the design of metal parapets in certain circumstances, is not considered appropriate for reinforced masonry constructions. For unreinforced masonry parapets only low and normal containment levels are specified since the use of unreinforced masonry at the high risk sites associated with high level containment is not appropriate due to the possibility of masonry becoming detached as a result of an impact. Advice is included for alternative levels of containment where the vehicle speed or angle of impact with the parapet may be restricted see annex B. The main objectives of the types of parapet defined in this part of BS 6779 are a to provide specified levels of containment to limit penetration by errant vehicles; b to protect highway users and others in the vicinity by either redirecting vehicles on to a path close to the line of the parapet, or arresting the vehicle motion with acceptable deceleration forces; c to reduce the risk of errant vehicles overtopping the parapet or overturning. It is possible in the case of both reinforced and unreinforced masonry parapets to give design criteria to produce satisfactory designs. In consequence full scale acceptance testing, as required for metal parapets in part 1 of this standard, is not necessary. The criteria for reinforced masonry parapets include equivalent static loads for the design of the parapet. In unreinforced masonry parapets a significant proportion of the kinetic energy of an impacting vehicle is absorbed by momentum transfer into the masonry, in addition to that absorbed by structural deation. The criteria for unreinforced masonry parapets are, therefore, based on the materials of construction and dimensions of the parapets. NOTEComposite action with the main structure can be minimized by the sub-division of parapets into panels. 1 Scope This part of BS 6779 specifies requirements for the design and construction of a specific of reinforced, and various s of unreinforced, masonry parapets which are designed to provide specified levels of containment for vehicles on highways. This part of BS 6779 also specifies requirements for the assessment of existing unreinforced masonry parapets. This part of BS 6779 is applicable to unreinforced masonry parapets of 10 m or greater in length or, if the parapet contains movement joints, with a minimum panel length between joints of 10 m and to reinforced masonry parapets with panels 2 m, or greater, in length. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions 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 referred to applies. BS 1449-21983, Specification for stainless and heat-resisting steel plate, sheet and strip. BS 39211985, Specification for clay bricks. BS 44491997, Specification for carbon steel bars for the reinforcement of concrete. BS 5328-21997, Concrete Part 2 s for specifying concrete mixes. BS 5328-31990, Concrete Part 3 Specification for the procedures to be used in producing and transporting concrete. BS 5328-41990, Concrete Part 4 Specification for the procedures to be used in sampling, testing and assessing compliance of concrete. BS 53901976, Code of practice for stone masonry. BS 5400-21978, Steel, concrete and composite bridges Part 2 Specification for loads. Licensed Copy Giorgio Cavalieri, ALSTOM, 5-Mar-01, Uncontrolled Copy. BSI 2 BSI 08-1999 BS 6779-41999 BS 5400-31982, Steel, concrete and composite bridges Part 3 Code of practice for design of steel bridges. BS 5400-41990, Steel, concrete and composite bridges Part 4 Code of practice for design of concrete bridges. BS 5628-11992, Code of practice for use of masonry Part 1 Structural use of unreinforced masonry. BS 5628-21995, Code of practice for use of masonry Part 2 Structural use of reinforced and prestressed masonry. BS 5628-31985, Code of practice for use of masonry Part 3 Materials and components, design and workmanship. BS 6073-11981, Precast concrete masonry units Part 1 Specification for precast concrete masonry units. BS 6073-21981, Precast concrete masonry units Part 2 for specifying precast concrete masonry units. BS 64571984, Specification for reconstructed stone masonry units. BS 67441986, Specification for austenitic stainless steel bars for the reinforcement of concrete. BS 6779-11998, Highway parapets for bridges and other structures Part 1 Specification for vehicle containment parapets of metal construction. BS 8000-31989, Workmanship on building sites Part 3 Code of practice for masonry. BS EN 10088-11995, Stainless steels Part 1 List of stainless steels. BS EN ISO 3506-11998, Mechanical properties of corrosion resistant stainless steel fasteners Part 1 Bolts, screws and studs. BS EN ISO 3506-21998, Mechanical properties of corrosion resistant stainless steel fasteners Part 2 Nuts. 3 Terms and definitions For the purposes of this part of BS 6779, the following terms and definitions apply. 3.1 vehicle restraint system installation to provide a level of containment for errant vehicles to limit damage or injury to users of the highway 3.2 highway parapet barrier at the edge of a bridge, or on top of a retaining wall or similar structure, associated with a highway 3.3 safety fence installation provided for the protection of users of the highway consisting of horizontal beams or wire ropes mounted on posts 3.4 front face face nearest to the traffic 3.5 outer face face furthest from traffic 3.6 supporting structure part of the bridge, retaining wall or other structure on which the parapet is mounted 3.7 adjoining paved surface paved area on the traffic side of a parapet, immediately adjacent to the base of a parapet 3.8 datum for height considerations highest level of footway, verge, carriageway or any other part of the road construction, on a horizontal line at right angles to the line of the parapet and within 1.5 m of the front face NOTEThis will normally be the adjoining paved surface. 3.9 datum for design considerations transverse plane through the parapet, or at the intersection with the main structure, which is critical for design purposes 3.10 top of parapet top of coping for determining parapet height with respect to the datum for height considerations or top of front face of parapet for determining height for impact considerations 3.11 anchorage arrangement within the supporting structure to which the parapet is direc
展开阅读全文
