AS3845 - Road Safety Barrier System

AS/NZS 3845:1999

Australian/New Zealand Standard™

Road safety barrier systems

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AS/NZS 3845:1999

This Joint Australian/New Zealand Standard was prepared by Joint TechnicalCommittee CE/33, Road Safety Barrier Systems. It was approved on behalf of theCouncil of Standards Australia on 9 October 1998 and on behalf of the Council ofStandards New Zealand on 12 October 1998. It was published on 5 January 1999.

The following interests are represented on Committee CE/33:

Australian Automobile AssociationAustralian Motorcycle CouncilAUSTROADSComposites Institute of AustraliaDepartment of Transport, S.A.Galvanizers Association of AustraliaInstitution of Engineers AustraliaMetal Trades Industry Association of AustraliaNew Zealand Concrete SocietyNew Zealand Employers and Manufacturers AssociationNew Zealand Manufacturers FederationPlastics and Chemicals Industries AssociationQueensland University of TechnologyTransit New Zealand

Review of Standards. To keep abreast of progress in industry, Joint Australian/New Zealand Standards are subject to periodic review and are kept up to date by the issueof amendments or new editions as necessary. It is important therefore that Standards usersensure that they are in possession of the latest edition, and any amendments thereto.Full details of all Joint Standards and related publications will be found in the StandardsAustralia and Standards New Zealand Catalogue of Publications; this information issupplemented each month by the magazines ‘The Australian Standard’ and ‘StandardsNew Zealand’, which subscribing members receive, and which give details of newpublications, new editions and amendments, and of withdrawn Standards.Suggestions for improvements to Joint Standards, addressed to the head office of eitherStandards Australia or Standards New Zealand, are welcomed. Notification of anyinaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should be madewithout delay in order that the matter may be investigated and appropriate action taken.

This Standard was issued in draft form for comment as DR 97016.

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AS/NZS 3845:1999

Australian/New Zealand Standard™


First published as AS/NZS 3845:1999.

Published jointly by:

Standards Australia1 The Crescent,Homebush NSW 2140 Australia

Standards New ZealandLevel 10, Radio New Zealand House,155 The Terrace,Wellington 6001 New Zealand

ISBN 0 7337 2293 8

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AS/NZS 3845:1999 2

PREFACE

This Standard was prepared by the Joint Standards Australia /Standards New ZealandCommittee CE/33, Road Safety Barrier Systems.

The objective of this Standard is to provide users with—

(a) issues that have to be addressed when specifying the installation of these devices;

(b) erection and maintenance practices necessary to achieve an acceptable level ofperformance;

(c) the process necessary to assess the nature of repairs to a road safety barrier system,or to a crash attenuator system following a crash; and

(d) methods to test road safety barrier and crash attenuator systems.

This Standard also provides details of non-patented road safety barrier systems that aredeemed to comply with this Standard.

This Standard describes a means of evaluating road safety barrier systems, based on thebest practices identified by the Committee. The National Cooperative Highway ResearchProgram (NCHRP) of the United States Report Number 350 has been adopted as the basisof testing. This Standard is to be read in conjunction with NCHRP Report 350. Referenceto CEN Standards is made in NCHRP 350. The Committee notes that the provisions arerudimentary and steps are being taken which may lead to a mutual recognition of tests infuture NCHRP and CEN documents.

Statements expressed in mandatory terms in notes to tables are deemed to be requirementsof this Standard.

The terms ‘normative’ and ‘informative’ have been used in this Standard to define theapplication of the appendix to which they apply. A ‘normative’ appendix is an integralpart of a Standard, whereas an ‘informative’ appendix is only for information andguidance.

© Copyright STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND

Users of Standards are reminded that copyright subsists in all Standards Australia and Standards New Zealand publications and software.Except where the Copyright Act allows and except where provided for below no publications or software produced byStandards Australia or Standards New Zealand may be reproduced, stored in a retrieval system in any form or transmitted by any meanswithout prior permission in writing from Standards Australia or Standards New Zealand. Permission may be conditional on anappropriate royalty payment. Australian requests for permission and information on commercial software royalties should be directed tothe head office of Standards Australia. New Zealand requests should be directed to Standards New Zealand.

Up to 10 percent of the technical content pages of a Standard may be copied for use exclusively in-house by purchasers of theStandard without payment of a royalty or advice to Standards Australia or Standards New Zealand.

Inclusion of copyright material in computer software programs is also permitted without royalty payment provided such programsare used exclusively in-house by the creators of the programs.

Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Standardis amended or revised. The number and date of the Standard should therefore be clearly identified.

The use of material in print form or in computer software programs to be used commercially, with or without payment, or in commercialcontracts is subject to the payment of a royalty. This policy may be varied by Standards Australia or Standards New Zealand at any time.

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3 AS/NZS 3845:1999

CONTENTS

Page

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SECTION 1 SCOPE AND GENERAL1.1 SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.2 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.3 REFERENCED DOCUMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.4 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.5 NOTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121.6 GENERAL REQUIREMENTS FOR ROAD BARRIER SAFETY SYSTEMS 131.7 USE OF OTHER MATERIALS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

SECTION 2 ROAD SAFETY BARRIER SYSTEMS AND CRASH ATTENUATORS2.1 SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.2 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.3 DESIGN AND DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152.4 SUPPLY AND ERECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192.5 MAINTENANCE AND DISMANTLING . . . . . . . . . . . . . . . . . . . . . . . . . 262.6 POST-CRASH ASSESSMENT AND REPAIR. . . . . . . . . . . . . . . . . . . . . . 27

SECTION 3 RIGID ROAD SAFETY BARRIER SYSTEMS3.1 SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283.2 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283.3 DEVELOPMENT OF DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283.4 ANALYSIS OF STRESSES IN RIGID ROAD SAFETY

BARRIER SYSTEMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.5 OTHER RESULTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.6 RIGID ROAD SAFETY BARRIER PROFILE. . . . . . . . . . . . . . . . . . . . . . 303.7 FOUNDATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303.8 COMBINATIONS OF RIGID ROAD SAFETY BARRIER SYSTEM

AND RAIL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303.9 PROXIMITY OF KERBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323.10 PROVISION FOR PEDAL CYCLISTS AND PEDESTRIANS. . . . . . . . . . 323.11 TERMINALS AND INTERFACE DETAILS . . . . . . . . . . . . . . . . . . . . . . . 323.12 RIGID ROAD SAFETY BARRIER SYSTEMS IN PUBLIC DOMAIN . . . . 32

SECTION 4 NON-RIGID ROAD SAFETY BARRIERS4.1 SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.2 DESIGN OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS. . . . . . . 424.3 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.4 DEVELOPMENT OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS . 424.5 PUBLIC DOMAIN NON-RIGID ROAD SAFETY BARRIER SYSTEMS . . 44

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Page

SECTION 5 TESTING5.1 SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.2 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.3 MODIFICATIONS TO NCHRP 350. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

APPENDICESA BACKGROUND INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53B COMMENTARY ON SECTION 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55C COMMENTARY ON SECTION 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69D COMMENTARY ON SECTION 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74E COMMENTARY ON SECTION 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79F DETAILS OF ROAD SAFETY BARRIER LAYOUT . . . . . . . . . . . . . . . . . . 80

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5 AS/NZS 3845:1999

FOREWORD

The intent of this Standard is to provide a framework that unites the many partiesinvolved in the provision of road safety barrier systems and crash attenuators, so that thecompleted installations provide acceptable performance to the community of road usersover the length of time the barrier systems are expected to operate.

The function of these devices is to improve road safety by reducing the consequences ofcrashes. However, it should be recognized that these devices are themselves a hazard; theyhave the potential to cause serious injuries. The intention of this Standard is that thesedevices are only installed at locations where the riskwith the device installed issignificantly less than the riskwithout the device.

The duty of care to be exercised is emphasized. The community of road users includespeople in a variety of vehicles which vary in size, mass and methods of propulsion. Whatshould be noted is that the users of these vehicles have different levels of protection,especially pedal cyclists and motorcyclists. The community of road users also includespedestrians and those involved in the various construction, operational and maintenanceactivities that occur within the road reserve. At some sites, the community of road usersshould be extended to include those whose activities require them to abut the roadreserve.

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AS/NZS 3845:1999 6

STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND

Australian /New Zealand Standard


S E C T I O N 1 S C O P E A N D G E N E R A L

1.1 SCOPE This Standard sets out the requirements for roadside devices that providesome degree of redirection and containment capability when impacted by a vehicle, orprovide controlled absorption of the kinetic energy of a vehicle that is on a collisioncourse with some significant obstacle.

This Standard includes the following:

(a) Methods and data to test road safety barrier and crash cushion systems.

(b) Issues to be addressed in specifying these devices.

(c) Erection and maintenance practices necessary to achieve acceptable performance.

(d) Steps to evaluate the nature of repairs necessary for road safety barrier systemsfollowing a crash.

The Standard also provides details of non-patented road safety barriers that are deemed tocomply with this Standard.

Where the terms ‘vehicle’ or ‘impacting vehicles’ are referred to in this Standard for theconsideration of effects on or by a road safety barrier system, these terms include thefollowing:

(i) Motorized vehicles, such as cars, trucks and motorcycles.

(ii) Non-motorized vehicles, such as pedal cycles and horse-drawn vehicles.

(iii) Operators, drivers and riders of vehicles specified in Items (i) and (ii) whetherattached or unattached to their vehicle.

(iv) Any other road users, considered appropriate to the conditions being assessed.

This Standard is to be read in conjunction with NCHRP Report Number 350.

NOTE: For commentary on this Section, see Appendix A.

1.2 APPLICATION This Standard applies to both permanent road safety barriersystems and road safety barrier systems designed to be readily erected and dismantled. Italso applies to devices meant for the applications given in Table 1.2.

This Standard does not apply to the following:

(a) Road safety barrier systems erected for special purposes, such as motor racing, orwhere special permit vehicles are the design focus.

(b) Where individual elements of a road safety barrier system are used for specialpurposes, such as protection of gas tanks and delineation of car parks.

(c) Pedestrian fences.

(d) Truck-mounted attenuators (TMAs).

(e) The comparative performance of road safety barrier systems or the preferred type ofroad safety barrier system to be installed.

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(f) Procedures to locate a road safety barrier system, either longitudinally ortransversely, or with related issues considered in positioning of road safety barriers,such as sight distance, drainage, aesthetics, cost and environmental matters.

A fundamental requirement in the application of this Standard shall be the use of riskmanagement techniques. These techniques shall be used to evaluate the hazards and theassociated risks to the community of road users. Where appropriate, the neighbours to aroad shall be included in the analysis. The outcome sought shall be a balanced decisionthat considers the probable benefits, the resources available and the competing investmentopportunities.

TABLE 1.2

TYPICAL APPLICATIONS

Installationtype

Typical applications

Manoeuvre speed(0 to 15 km/h)

Low speed(15 to 60 km/h)

Arterial, sub-arterialand collector roads

Permanent road safetybarriers

Car parks and sites withfeatures requiringprotection fromincidental impact

Local streets, campusesand roads with restricteddesign standards

Arterial, sub-arterial andcollector roads

Temporary road safetybarriers (devicesdesigned to be erectedand dismantled quickly)

Work sites in car parks Work sites on localstreets with infrequentmovements of vehicleslarger than 2000 kg

Work sites on arterial,sub-arterial and collectorroads

Crash attenuators Not appropriate Gore areas andapproaches to toll booths

Gore areas andapproaches to toll booths

1.3 REFERENCED DOCUMENTS The following documents are referred to in thisStandard:

AS1163 Structural steel hollow sections

1214 Hot-dip galvanized coatings on threaded fasteners (ISO metric coarse threadseries)

1302 Steel reinforcing bars for concrete

1303 Steel reinforcing wire for concrete

1304 Welded wire reinforcing fabric for concrete

1348 Road and traffic engineering—Glossary of terms1348.1 Part 1: Road design and construction

1379 Specification and supply of concrete

1604 Timber—Preservative-treated—Sawn and round

1627 Metal finishing—Preparation and pretreatment of surfaces1627.5 Part 5: Pickling, descaling and oxide removal

1650 Hot-dipped galvanized coatings on ferrous articles

1742 Manual of uniform traffic control devices1742.3 Part 3: Traffic control devices for works on roads

3569 Steel wire ropes

3610 Formwork for concrete

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AS/NZS 3845:1999 8

AS/NZS1111 ISO metric hexagon commercial bolts and screws

1112 ISO metric hexagon nuts, including thin nuts, slotted nuts and castle nuts

1252 High strength steel bolts with associated nuts and washers for structuralengineering

1554 Structural steel welding1554.1 Part 1: Welding of steel structures1554.5 Part 5: Welding of steel structures subject to high levels of fatigue loading

1594 Hot-rolled steel flat products

1595 Cold-rolled, unalloyed, steel sheet and strip

3678 Structural steel—Hot-rolled plates, floorplates and slabs

3679 Structural steel3679.1 Part 1: Hot-rolled bars and sections

3750 Paints for steel structures3750.9 Part 9: Organic zinc-rich primer

4360 Risk management

BS4483 Specification for steel fabric for the reinforcement of concrete

NZS3112 Methods of test for concrete

3114 Specification for concrete surface finishes

3402 Steel bars for the reinforcement of concrete

3421 Specification for hard drawn mild steel wire for concrete reinforcement

TRANSIT NZ, Bridge Manual, Transit New Zealand, Wellington 1994.

The National Cooperative Highway Research Program (NCHRP) Report 350,‘Recommended Procedures for the Safety Performance Evaluation of Highway Features’(NCHRP 350), Ross, Sicking, Zimmer and Michie, Washington DC, 1993.

1.4 DEFINITIONS For the purpose of this Standard, the definitions in AS 1348 andthose below, shall apply.

1.4.1 Agency—the organization responsible for managing that part of the road networkwhere a safety barrier or crash attenuator is proposed.

1.4.2 Anchor bracket—a bracket used to anchor the cable assembly to the end rail ofthe modified eccentric loader terminal (MELT) and trailing terminal (TT).

1.4.3 Average recurrence interval (ARI)—a measure of the probability associated witha given flood event.

1.4.4 Bearing plate—a plate to anchor the cable assembly at the first post of the MELTterminal.

1.4.5 Blockout—used to offset the beam from the post.

1.4.6 Buffered end section—the curved section used to terminate the modified eccentricloader terminal (MELT) and trailing terminal (TT).

1.4.7 Cable assembly—used to anchor the terminal rail of the MELT and TT terminals.

1.4.8 Can—a capability or a possibility and refers to the ability of the user of theStandard, or to a possibility that is available or that might occur.

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1.4.9 Clear zone—the horizontal width of space available for the safe use of an errantvehicle which consists of the verge area and is measured from the nearside edge of theleft-hand traffic lane. In the case of a divided road, it is also measured from the offsideedge of the right-hand traffic lane to the edge of the pavement for opposing traffic.

NOTE: This area may consist of a shoulder, a recoverable slope, a non-recoverable slope and arunout area, but all parts can be traversed. The desirable width is dependent on traffic volumes,speeds and the geometry of the road.

1.4.10 Concave—if viewed from the perspective of a road user, the actual midpoint of aconcave installation, or a concave portion of an installation, lies behind the straight linejoining the start and finish of the installation, or joining the start and finish of the concaveportion of the installation.

1.4.11 Convex—if viewed from the perspective of a road user, the actual midpoint of aconvex installation, or a convex portion of an installation, lies in front of the straight linejoining the start and finish of the installation, or joining the start and finish of the convexportion of the installation.

1.4.12 Crash—an event or a series of events resulting from a vehicle colliding withanother person or object, likely to cause property damage, serious injury or death to thevehicle occupants or to persons struck.

1.4.13 Crash attenuators—devices that prevent an errant vehicle from impactinghazardous objects by gradually decelerating the vehicle to a safe stop or by directing thevehicle away from the hazard. They are often used as the end treatment on the leading endof a road safety barrier system.

1.4.14 Crash testing—conducting a series of full scale impact tests on a road safetybarrier system in accordance with recommended guidelines, e.g. NCHRP 350, asappropriate.

1.4.15 Deemed to comply—accepted as complying with the criteria specified inNCHRP 350.

1.4.16 Design horizontal force—an equivalent static force applied horizontally to aroad safety barrier system to represent the dynamic force imparted to a road safety barriersystem by an idealized and specified design vehicle, impacting the road safety barriersystem at a designated speed and angle.

1.4.17 Design life—the length of time during which a road safety barrier system isrequired to perform its function without any repair.

1.4.18 Diaphragm plate—stiffener plate for use in buffered end section.

1.4.19 Dynamic deflection—the largest transverse deflection of a road safety barriersystem recorded during an actual crash or during a full scale impact test.

1.4.20 End treatment—the collective term for devices and features at the leading andtrailing ends of road safety barrier systems, which are selected on the basis of trafficspeed and composition, the type of road barrier system and the particular site constraints.

1.4.21 Flare—change in the offset of a road safety barrier to move it further from thetravelled way or closer to the travelled way.

1.4.22 Flare rate—ratio of the longitudinal distance to the transverse offset by which aroad safety barrier flares away from, or towards, the edge of the travelled way. It can beexpressed as a percentage.

1.4.23 Gating terminals—terminals that are designed to break away, pivot or hinge,and that allow a vehicle to pass through when impacted at an angle to the end, or at apoint upstream of the beginning of the length of the associated road safety barrier system.

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1.4.24 Interface—the length of road safety barrier systems used to connect systemswith different operating characteristics. It is commonly used to connect a non-rigid roadsafety barrier system to a rigid road safety barrier system, such as a bridge safety barrier.

1.4.25 Length of need—the length of a road safety barrier system, excluding leading ortrailing terminals, needed to prevent errant vehicles colliding with a roadside hazard.

1.4.26 Longitudinal road safety barrier system—a road safety barrier system whoseprimary function is to prevent penetration and to safely redirect an errant vehicle awayfrom a nearside, or an offside hazard.

1.4.27 Maintainer—the team that undertakes all relevant works to maintain the roadsafety barrier system in a safe working condition.

1.4.28 Manufacturer—the team that manufactures all the components of a recognizedroad safety barrier system and supplies it to a site for erection.

1.4.29 May—indicates the existence of an option.

1.4.30 Median—the portion of a divided highway separating the travelled ways betweentraffic travelling in opposite directions.

1.4.31 Median road safety barrier system—longitudinal road safety barrier systemdesigned to be impacted from either side.

1.4.32 Modified blockout—a notched blockout used with a thrie-beam road safetybarrier system.

1.4.33 Modified eccentric loader terminal (MELT)—a public domain gating terminal.

1.4.34 Nearside—the side of a vehicle closest to the kerb when the vehicle is travellingin the normal direction of travel. The nearside of a road corresponds to the left-hand ofthe carriageway when looking in the direction of travel.

1.4.35 Non-gating terminals—terminals that are designed to redirect a vehicle andabsorb part of the energy of an impacting vehicle at any point along the terminal withoutallowing it to pass behind the road safety barrier system.

1.4.36 Non-recoverable slope—a slope that is considered traversable but on which theerrant vehicle will continue on to the bottom of the slope.

1.4.37 Non-rigid road safety barrier system—a road safety barrier system whereelements are designed to move substantially in a crash, and where energy is absorbed bymovement of the road safety barrier system and deformation of the vehicle.

1.4.38 Offside—the side of a vehicle furthest away from the kerb when the vehicle istravelling in the normal direction of travel. It corresponds to the driver’s side of thevehicle. The offside of a road corresponds to the right-hand side of the carriageway whenlooking in the direction of travel.

1.4.39 Pipe sleeve—a sleeve to take the cable assembly through the first post of theMELT terminal.

1.4.40 Post—the component supporting the beams of a public domain non-rigid roadsafety barrier system and a wire rope road safety barrier system.

1.4.41 Proprietary system—a road safety barrier system that is the subject of patent orother intellectual property rights within Australia and New Zealand.

1.4.42 Public domain system—a road safety barrier system that is not the subject ofpatent or other intellectual property rights within Australia and New Zealand.

1.4.43 Recoverable slope—a slope on which a motorist may, to some degree, retain orregain control of a vehicle. Slopes flatter than 4:1 are generally considered recoverable.

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1.4.44 Rigid road safety barrier system—a road safety barrier system where there isno observable dynamic deflection. The deformation is contained in the impacting vehicle.

1.4.45 Risk—the chance of something happening, which will have an impact uponobjectives. It is measured in terms of consequences and likelihood (see AS/NZS 4360).

1.4.46 Risk analysis—the systematic use of available information to determine howoften specified events may occur and the magnitude of their likely consequences(see AS/NZS 4360).

1.4.47 Risk management—the systematic application of management policies,procedures and practices to the tasks of identifying, analysing, assessing, treating andmonitoring risk (see AS/NZS 4360).

1.4.48 Road safety barrier system—a roadside device that provides a physicalrestriction to penetration of a vehicle in a way that reduces the risk to vehicle occupantsand other traffic. Its purpose is to contain or redirect an errant vehicle. It is used to shieldroadside obstacles or non-traversable terrain features. Occasionally, it may be used toprotect people from vehicular traffic.

1.4.49 Shall—indicates that a statement is mandatory.

1.4.50 Shelf angle—used to support the W-beam at the posts in the MELT and TTterminals.

1.4.51 Should—indicates a recommendation.

1.4.52 Shy-line—the distance from the edge of the travelled way beyond which aroadside object will not be perceived as an immediate hazard by the typical driver, to theextent that they will not change their vehicle’s placement or speed.

1.4.53 Specifier—a person or a team that produces the drawings and specifications forinstallation at a specified site.

1.4.54 Stiffener—plate located behind the W-beam and thrie-beam at the midspan post.

1.4.55 Structure connector—the plate used to connect W-beam and thrie-beam to arigid barrel or bridge road safety barrier system.

1.4.56 Strut and yoke—used for connecting the first and second posts at ground levelin the MELT terminal.

1.4.57 Temporary road safety barrier system—a device designed to be erected anddismantled quickly, used to prevent vehicular access into construction or maintenancework zones. Its purpose is to redirect an impacting vehicle so as to minimize damage tothe vehicle and injury to the occupants, while providing worker protection.

1.4.58 Terminal—the specially designed end pieces of a road safety barrier system. Theleading terminal is on the end of the road safety barrier system that faces oncoming trafficand the trailing terminal is on the other end. Terminals are subdivided into theclassifications of gating and non-gating terminals (see Clauses 1.4.15 and 1.4.25).

1.4.59 Test level (TL)—a set of conditions, defined in terms of vehicular type andmass, vehicular impact speed, and vehicular impact angle, that quantifies the impactseverity of a matrix of tests.

1.4.60 Test vehicle—a commercially available, production model vehicle or anapproved surrogate vehicle used in a crash test to evaluate the impact performance of atest article.

1.4.61 Thrie-beam—the triple corrugated beam component of a public domain non-rigid road safety barrier system.

1.4.62 Transition beam—the corrugated beam used for the changeover from a thrie-beam road safety barrier system to a W-beam road safety barrier system.

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1.4.63 UV—ultraviolet radiation.

1.4.64 Verge—the land area between the pavement and another pavement or between apavement and the property line.

1.4.65 W-beam—the double corrugated beam component of a public domain non-rigidroad safety barrier system.

1.4.67 Whole of life cost—the sum of the annualized costs associated with thecommissioning, routine maintenance and repair costs of a road safety barrier system.

1.4.68 Working width—the maximum width that is required to prevent an impactingvehicle from colliding with an object behind a road safety barrier system. This includesboth the dynamic deflection (if any) and the extra width due to the roll of the impactingvehicle.

1.4.69 Work zone—a length of road where roadworks are taking place.

1.4.70 85th percentile—85% of all recorded values will be less than or equal to the85th percentile value.

1.5 NOTATION The notation used in this Standard is given in Table 1.6.

Where non-dimensional ratios are involved, the numerator and denominator are expressedin identical units.

The dimensional units for length and stress in all expressions or equations are to be takenas millimetres (mm) and megapascals (MPa) respectively, unless specifically notedotherwise.

TABLE 1.5

NOTATION USED IN CLAUSE 3.5

Symbol Description

alat lateral vehicle deceleration

b width of the vehicle

c height of the vehicle’s centre of gravity above ground

Flat horizontal force

g acceleration due to gravity

glat horizontal vehicle deceleration

hact height of road safety barrier system

heff effective height of the road safety barrier system

hi height of the impact force above road surface

lc critical length of the yield line failure pattern

l t longitudinal length of the distributed impact force

m mass of the vehicle

Mb additional flexural resistance of a beam

Mc flexural resistance of the foundation or cantilever

Mo moment about the contact point ‘O’

Mw flexural resistance of the road safety barrier wall

R total resistance of the road safety barrier system

∆ horizontal displacement of the road safety barrier system or rail, or both

µ coefficient of the pavement friction

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1.6 GENERAL REQUIREMENTS FOR ROAD SAFETY BARRIER SYSTEMS Tocomply with this Standard, road safety barrier systems shall be—

(a) supported by technical literature and assembly instructions that clearly illustrate theessential mode of operation and prominently show the test level achieved in crashtesting that has been carried out in accordance with this Standard;

(b) selected and located in accordance with a recognized design procedure that isprofessionally applied. This procedure shall take account ofrisk managementtechniques that address the community of road users and neighbours, which may beaffected by the installation;

(c) erected in accordance with the manufacturer’s instructions;

(d) maintained in a manner that reflects the specified requirements;

(e) returned into service following a crash only after professional evaluation andexecution of repairs; and

(f) fitted with end treatments and interface devices that are appropriate to the systembeing used.

1.7 USE OF OTHER MATERIALS This Standard is not to be interpreted to meanthat it prevents the use of materials or products not specifically referred to in thisdocument. Substitution shall only occur with the agreement of both the agency and themanufacturer.

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AS/NZS 3845:1999 14

S E C T I O N 2 R O A D S A F E T Y B A R R I E RS Y S T E M S A N D C R A S H A T T E N U A T O R S

2.1 SCOPE This Section applies to all road safety barrier systems and crashattenuators. It specifies the general requirements that shall be addressed by those owning,specifying, constructing, maintaining and refurbishing such devices.

The Section sets out the range of operating conditions that apply, and details the values ofother parameters that shall be used where specific site information is not available. Itprovides details of the performance issues that shall be covered in documentation dealingwith the supply of safety systems.

NOTE: For commentary on this Clause, See Paragraph B2.1 of Appendix B.

2.2 GENERAL

2.2.1 Required information Where a road safety barrier system is to be installed, thesite, road safety barrier system and crash attenuator information shall be determined inaccordance with Clauses 2.2.2, 2.2.3 and 2.2.4.

2.2.2 Site information At sites where a road safety barrier system is proposed, thefollowing data shall be obtained, recorded and made available:

(a) General details of the site.

(b) Design vehicle to be adopted, e.g. mass and principal dimensions.

(c) Impact speed and angle to be used for design purposes.

(d) Period of time the road safety barrier system will be required to operate.

(e) Provisions for access, e.g. traffic, pedestrians and fauna crossings.

(f) The proposed topography and nature of the ground in front of the road safety barriersystem, sufficient to allow the likely approach elevation of an errant vehicle to beestablished.

(g) Details of the topography at the leading end of the road safety barrier system andany restrictions on the use of gating terminals.

(h) Associated infrastructure constraints, such as drainage installations, footways andmaintenance access requirements to road furniture and the like.

(i) Existing delineation.

(j) Operational temperature range.

(k) Flooding.

(l) Other site information.

NOTE: For commentary on this Clause, see Paragraph B2.2.2 of Appendix B.

2.2.3 Road safety barrier system information Where a road safety barrier system isproposed, the following shall be obtained, recorded and made available:

(a) The points where the need for a road safety barrier system begins and ends (lengthof need).

(b) Minimum transverse offset required from the edge of the adjacent traffic lane.

(c) Allowable dynamic deflection and working width restrictions.

(d) Interfaces with existing systems.

(e) The nature of the ground or structural support that is required.

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(f) Provisions that have to be made for expansion or contraction of the foundation.

(g) Whether gating devices can be used as terminals.

(h) The nature of any road furniture or systems that have to be incorporated, such asacoustic devices, delineators, sign support systems, lighting columns and the like.

(i) Spacing and nature of provisions for access through the road safety barrier systemin an emergency or for planned work that requires different traffic arrangements forshort periods.

(j) Whether traffic can impact the road safety barrier system in the reverse direction.

2.2.4 Crash attenuator information Where a crash attenuator is required, thefollowing shall be obtained, recorded and made available:

(a) The nature of the hazard being protected and the live loads (if any) it can resist.

(b) Whether traffic can impact the attenuator in the reverse direction.

(c) Whether gating devices can be used.

(d) Foundation conditions and installation restrictions.

2.3 DESIGN AND DOCUMENTATION

2.3.1 General The process of specifying, constructing and maintaining these devicesshall be documented. Assessment after a crash shall be carefully carried out and anyshortcomings shall be addressed in subsequent designs and any revisions of thedocuments.

‘Whole of life’ costs shall be used in the evaluation of all road safety barrier systemsproposals. These shall include costs to road users and any additional costs borne bypeople whose access and amenity may be affected. The storage requirements for elementsof the road safety barrier systems, which may be replaced during routine maintenance, orafter a collision, shall form part of this analysis.

NOTE: The appearance of a road safety barrier system may be an important issue at some siteswhere compatibility with other architectural and geological features is essential.

Sight lines through the road safety barrier system for operational purposes, or to allowglimpses of scenic vistas, shall be an acceptable selection criterion.

The location of the road safety barrier system and its footings shall not—

(a) interfere with any services, drainage conduits or structures; nor

(b) impair access of personnel or machinery to any services, drainage conduits orstructures.


2.3.2 Operational temperature range Road safety barrier systems shall operate overan ambient temperature range of −20°C to +50°C without any reduction in effectiveness.


2.3.3 Environment The materials and components used in all road safety barriersystems and end treatments shall be specified. They shall meet the design life defined inClause 1.4.17.

Particular environmental issues, such as snow drifts, glare, accumulation of windbornerubbish, shall also be considered. Modifications that are necessary to cope with crashdebris, such as chemical spills, shall be taken into account using a risk managementtechnique.


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2.3.4 Flooding Road safety barrier systems or components that cannot be submergedshall be documented. Also, road safety barrier systems, which can be rendered ineffectiveor which can have a reduced performance as a result of flooding, shall not be used inflood-prone areas. The effect of the road safety barrier system on the flood flows shall beconsidered.


2.3.5 System details All road safety barrier systems and crash attenuators shall betested in accordance with the procedures specified in this Standard. The followingdocumentation on road safety barrier systems, except those manufactured in cast-in-placeconcrete, shall be available:

(a) The test level achieved. The technical literature shall provide details of the testcertificates, together with details of the site conditions and the road safety barrierconfiguration at the time it was certified to that test level.

(b) The working width and the dynamic deflection width that applies to the road safetybarrier system at the test level achieved. Where anchors are part of the road safetybarrier system, the relationship between the anchorage spacing, the working widthand the dynamic deflection width shall be specified. Where the road safety barriersystem comprises inter-connected elements, then any relationship between thenumber of units, the working width and the dynamic deflection width shall bespecified.

(c) The points at the leading and trailing ends of a road safety barrier system where theroad safety barrier system becomes effective, and any minimum lengthrequirements. Details shall be provided of any special requirements where longlengths of the road safety barrier system shall be installed.

(d) The maximum flare rates that apply when the road safety barrier system is locatedinside the shy-line and beyond the shy-line. This can be expressed as a ratio or as apercentage.

Flares at the appropriate flare rate may be used instead of a terminal, provided theflare extends beyond the clear zone.

NOTE: Approved road safety barrier systems that comply with this Standard should be markedwith an inscription bearing the following words:

THIS ROAD SAFETY BARRIER OR CRASH ATTENUATORCOMPLIES WITH AS/NZS 3845.

The material requirements for cast-in-place concrete road safety barrier systems shall beas specified in Clause 2.4.

The profile shapes given in Section 3 shall be used, unless crash testing shows that adifferent profile gives acceptable results.


2.3.6 Plan details The normal range of horizontal road curve radii, both concave andconvex, together with details of the dynamic deflection and working width shall bedocumented.

Details about any combinations of vertical and horizontal geometry that render the roadsafety barrier system ineffective, or reduce the efficiency of the road safety barriersystem, shall be documented. Details shall be provided where this range of applicationscan be extended by modifications.

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Both temporary and permanent road safety barriers shall be installed so that they arestructurally continuous, in accordance with the manufacturer’s specifications. Fortemporary installations, the continuity shall be able to resist a minimum tensile force of150 kN for test level 3 and above.

NOTES:

1 Lesser values of the minimum tensile force may be used for local and manoeuvrable speedapplications.

2 For commentary on this Clause, see Paragraph B2.3.6 of Appendix B.

2.3.7 Elevation details The range of crest and sag vertical curves where the roadsafety barrier system can be used shall be documented. These details shall be providedwhere the range of applications can be extended by modifications.

Any additional dynamic deflection and working width where installations are on a crest oron sag vertical curves shall be documented.


2.3.8 Transverse details For transverse details, the following information shall beavailable:

(a) The design details where the road safety barrier system is to be erected at locationswhere the cross-fall is less than 4.5% and any different installation proceduresrequired where the cross-fall is greater than or equal to 4.5%. These requirementsshall be specified in detail for temporary road safety barrier systems or for anysystems that cannot be fixed to the foundation.

(b) The method of establishing the height of the road safety barrier system at locationswhere kerbs, gutters, or other changes in level, occur in front of the road safetybarrier system.

(c) The prohibited and undesirable transverse details, such as the permissible positionand height of kerbs in front of the road safety barrier system which may affect theworking width and dynamic deflection, and create special hazards for pedal andmotorcyclists.

(d) The acceptable and prohibited practices regarding attachments, such as delineators,noise walls and light poles.


2.3.9 Foundation on natural ground Details of the foundation support necessary forthe road safety barrier system to operate effectively shall be specified. Details shallinclude the following:

(a) The ground conditions that are not appropriate.

(b) The horizontal extent of foundation support necessary, such as the minimumdistance required to hinge points on embankments.

(c) Installation requirements where elements of the road safety barrier system areinstalled in excavations, such as the anchor blocks necessary to allow some roadsafety barrier systems to withstand some tensile loads.

(d) Soil types that do not suit the road safety barrier system, i.e. soil materials that arelikely to reduce the design life of posts and expansive clays that may renderconcrete road safety barrier foundations unstable.

Where modifications are necessary to provide for extraordinary foundation conditions,then these shall be clearly stated.

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AS/NZS 3845:1999 18

The procedures where excavation to the specified depth is not practicable, where drivingposts to the required depth cannot be achieved, or where special care is necessary, shallbe documented. This shall include sites where rock may be encountered, public utilitiesare present or where there are site restrictions, such as underground drainage systems andstreet lighting conduits.


2.3.10 Foundations on structures Road safety barrier systems shall allow forexpansion and contraction of the supporting structure. The measures that are necessary toallow the road safety barrier system to accommodate the movements of supportingstructures under live loads shall be specified.

Failure mechanisms shall be identified and largely contained within the road safety barriersystem. Failure modes that result in serious damage or destruction of elements of thesupporting structure, to the extent that its capacity to perform and its intended function isreduced, shall not be acceptable.

Site constraints, such as the straps of reinforced earth walling systems, that require specialcare shall be documented, and the procedure to be used at sites where interference withsuch installation is possible shall be specified.

Where the strength or the serviceability of an existing structure is to be evaluated forerection of a road safety barrier system, then this Standard shall be applied. The actualproperties of the materials in the structure shall be used.


2.3.11 End treatment The selected end treatment shall be appropriate to the roadsafety barrier system used and tested in accordance with this Standard before it is used onthe road, to warrant the selected end treatment function as required. As tests areconducted in a controlled environment, the actual site conditions shall be considered whenselecting an end treatment.


Where the end treatment is classified as ‘gating’, the terrain for the run-out area behindsuch installations shall be detailed. Gating terminals shall only be selected for sites wherethe area behind the terminal is appropriate.

Temporary and permanent road safety barrier installations shall not be distinguished whenselecting end treatments. However, where the site is effectively managed, i.e. if themaximum traffic speed is controlled atall times, it shall be permissible to use the lowerposted speed limit at temporary installations instead of the normal value of the speedlimit.

2.3.12 Interfaces Where different road safety barrier systems adjoin, the interfacedetails shall be designed to achieve a gradual transition in the horizontal stiffness andheight. The difference in their horizontal stiffness shall not exceed 40% over a minimumlength of 2.5 m. Butting together two road safety barrier systems without properconnections for structural continuity, or only providing end treatments, such as installingadjoining, non-gating terminal systems, shall be prohibited.


2.3.13 Attachments Road furniture, such as delineators, headlight screens, signs,lighting posts and fences for pedestrians, shall not be attached to any road safety barriersystem unless it can be shown by crash testing, clearly documented historical informationor other professionally accepted methods of engineering analysis that this is acceptable.This shall particularly apply to road safety barrier systems that are designed to move onimpact, e.g. non-rigid systems.

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Attachment points for road furniture shall not be located in positions where they increasethe risk of snagging vehicles, nor shall they have features that create an undue hazard tothe community of road users, particularly pedestrians, pedal cyclists and motorcyclists.Sharp edges, pointed elements and dangerous protuberances shall be prohibited.


2.3.14 Emergency accessFor road safety barrier systems, details shall be provided ofthe method for rapid access through the road safety barrier system in emergencies. Detailsshall include the following:

(a) Acceptable and prohibited practices.

(b) Special tools required.

(c) Estimates of the time and resources necessary to dismantle median road safetybarrier system to allow an emergency vehicle to cross.

If a purpose-built road safety barrier system is used (which requires power to open thedevice), provision shall be made to allow manual operation.

For both nearside and off-side installations, permanent emergency access shall only beprovided at sites where the distance is sufficient to allow the manoeuvre to be completedwith safety.

If overlapping is used to provide emergency access, the minimum length, the length ofneed and flare rates shall be maintained.

2.3.15 Tolerances Fabrication tolerances shall be shown on the drawings. Componentsthat are galvanized or metal coated shall be measured before galvanizing or metal coating.

2.3.16 Modifications Modifications shall not be made to any road safety barriersystem, unless crash testing, computer simulation or other professionally acceptedmethods show that the change is acceptable.

2.3.17 Opening in the surface An opening in the surface of the road safety barriersystem shall be avoided in areas shown in Figure 2.3.17(1), unless the road safety barriersystem complies with full scale crash testing in accordance with this Standard. Means ofdetermining the extent of the opening shall be as shown in Figure 2.3.17(2).


2.3.18 Motorcycle road safety barrier system Road safety barrier systemscrash-tested for motorcycle impact shall provide smooth unbroken surfaces without sharpedges.

2.3.19 Impact conditions Road safety barrier systems shall be capable of resisting thevehicle impact parameters given in Table 2.3.19 for the appropriate level withoutpenetration.

Whilst penetration of the road safety barrier system by the design vehicle is notacceptable, severe damage and destruction of the elements during the crash is acceptableprovided that the damage does not cause accelerations in the impacting vehicle which areoutside the limits specified in NCHRP 350.


2.4 SUPPLY AND ERECTION

2.4.1 General Road safety barrier systems shall be erected so that the completed workfollows the details of the crash-tested installations. Erection practices that do not complywith the drawings and specification shall not be permitted.


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2.4.2 Damage All components of road safety barrier systems shall be stored,transported, stacked, handled and installed in such a way to prevent permanent damage,particularly to threaded components and components, such as wire ropes, that are prone todamage from twisting and kinking. Critical elements that are vulnerable to damage shallbe packaged in a manner that provides protection.


2.4.3 Component identification and assembly details To avoid confusion as to themethod of assembly, components of the road safety barrier system shall be identified anddocumented.

Components supplied shall be compared with this documentation and missing pieces shallbe documented. Any concerns about the identification of a particular element shall beclarified before attempting the erection.


TABLE 2.3.19

VEHICLE IMPACT PARAMETERS

Testlevel

Vehicle mass (kg)and type

Speed

km/h

Angle

degrees

Height of centreof gravity

mm

0 820 C 50 20 550

1 600 C 50 25 550

1 820 C 50 20 550

2 000 P 50 25 700

2 820 C 70 20 550

2 000 P 70 25 700

3 820 C 100 20 550

2 000 P 100 25 700

4 820 C 100 20 550

8 000 S 80 15 1 250

5 820 C 100 20 550

36 000 V 80 15 1 850

6 820 C 100 20 550

36 000 T 80 15 2 050

LEGEND:

C = small car

P = four wheel drive or utility truck

S = single-unit van truck

T = tanker type semi-trailer

V = van type semi-trailer

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NOTE: Avoid openings in cross-hatched areas.

DIMENSION IN MILLIMETRES

FIGURE 2.3.17(1) RESTRICTIONS ON OPENINGS IN ROAD SAFETYBARRIER SYSTEMS

FIGURE 2.3.17(2) MEANS OF DETERMINING MEASUREMENTS OF OPENINGSIN ROAD SAFETY BARRIER SYSTEMS

2.4.4 General tolerances A road safety barrier system that conforms to the specifiedtolerances shall be provided. The appearance of the road safety barrier system shall besmooth and even, i.e. free from kinks, in both the vertical and horizontal planes. For allsystems, the top of the road safety barrier system shall be within 20 mm of the specifiedlevel and 50 mm of the specified location shown on drawings.

In general, road safety barrier systems shall be so constructed that the principal axes arevertical. However, if they are installed on a foundation with a cross-fall of more than4.5%, they may be tilted to be perpendicular to the pavement. In such circumstances, thespecification shall be followed.


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2.4.5 Surface finish A road safety barrier system shall have a surface finish thatminimizes the friction between the system and an impacting vehicle.

The surface finish shall be uniform, resistant to incidental damage and shall not beaffected by detergents and similar agents that may be used to clean the external surfaces.

Protrusions from the surface, which are likely to be struck by an impacting vehicle, shallnot exceed 20 mm. Any protrusions shall be rounded or similarly treated, to reduce thepossibility of snagging the body work of a vehicle or catching at the person or clothing ofan individual.

After construction, components shall not be left with splits, burrs or sharp edges afterconstruction. Lapping of elements shall be in the direction of the potential path of anerrant vehicle.


2.4.6 Setting out Before commencing any construction, the start and finish points, andthe transverse location of any road safety barrier system, shall be marked. The location ofany transitions and terminals shall also be marked.

The minimum offset from the edge of the traffic lane shall be not less than 250 mm.(desirable 500 mm.)


2.4.7 Sequence of work Where a road safety barrier system is being constructed on aroad that is open to traffic, arrangements shall be made to the sequence of construction tominimize the hazard to road users. Leading terminals and any transitions between roadsafety barrier systems shall be commissioned at the earliest practicable time.


2.4.8 Installation acceptance criteria for posts Where posts form part of the roadsafety barrier system, they shall be installed to the depth, line and spacing shown on thedrawings. The tolerance on post spacing shall be ±25 mm. The tolerance on post heightshall be ±20 mm. The tolerance on the verticality of posts shall be ±15 mm, measured atthe top of the post. The tolerance on posts rotation shall be ±30 mm, measured as thedifference between the point of attachment of the post to the rail and the free position ofthis same point without the rail attached. After the posts are installed, all elements in theroad safety barrier system shall fit together without the need to enlarge any holes ormodify any component.

The installation process shall not cause damage to the post, such that it reduces theeffective operation of the road safety barrier system or its design life, or introduces sharptearing edges, nor shall it cause damage to any pavement layer located more than 100 mmaway from the post.

The orientation of posts shall be in accordance with the drawing. This shall apply to anyblock-out pieces that are required by the design.

Where the materials in the posts may be affected by rot or attack by termites, the requiredspecifications shall be followed.


2.4.9 Construction acceptance criteria for foundations For road safety barriersystems that are placed on formed foundations, the following criteria shall be met:

(a) The specified level of support shall be available.

(b) Where the road safety barrier system is non-rigid, then the specified treatments forthe interface of the system with the foundation shall be followed.

(c) Where the road safety barrier system is rigid, the method of attachment to thefoundation shall be followed.

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Where the sides of any excavation act as the former for any concrete work, then this shallbe neatly done.


2.4.10 Construction acceptance criteria for concrete construction Reinforcing steelshall be as shown on the drawings. For road safety barrier systems that are less than 1 min height, the area of reinforcement shall not be less than a total of 500 mm2/m length forthe horizontal and vertical directions. For road safety barrier systems greater than 1 m inheight, the area of reinforcement shall be at least 1000 mm2/m horizontally in both faces.A design check shall be made to ensure the road safety barrier system shall perform asintended.

NOTE: Checks for stresses that result from lifting the device may be appropriate with somedesigns.

For high-strength concrete, the concrete cover shall be as given in Table 2.4.10(1). At allsites, the minimum clear concrete cover shall be not less than 1.5 times the maximumnominal size of the aggregate, or 1.5 times the diameter of the reinforcing bar beingprotected. Reinforcing steel shall be supported using concrete or plastic chairs. Pieces ofwire, timber, reinforcing steel or coarse aggregate shall not be used to support reinforcingsteel. All reinforcement shall comply with AS 1302, AS 1303, NZS 3402 or NZS 3421.Tack-welded reinforcement shall be category GP in accordance with AS/NZS 1554.1 andcategory SP for any other welded reinforcement.

The maximum nominal size of aggregate for concrete shall be as shown on the drawings.The minimum content of cementatious material shall be 330 kg/m3.

Road safety barrier systems made of concrete shall be constructed using either pre-castsegments, placing concrete in fixed forms, or by slip forming. Concrete shall be placed ina continuous operation between construction joints. Fresh concrete shall not be placedagainst concrete that has taken its initial set. Concrete shall be thoroughly compacted.Unformed surfaces shall be tamped and screeded to the specified level. They shall betested for high or low spots, and any corrections shall be made immediately. On stripping,any repairs to the formed surfaces shall be carried out immediately. Concrete surfacesshall be finished to a class finish in accordance with AS 3610 or to a Class F4 finish inaccordance with NZS 3114.

Expansion joints shall be constructed as shown on the drawings. Expansion joints shall bestraight, square to the line of the road safety barrier system and to the specified width.Contraction joints shall be square to the line of the road safety barrier system and shall be50 ±5 mm deep. Spacing shall be at the specified interval but not more than 6.0 m apart.

Exposed surfaces shall be effectively protected from rain or damage from other causes,until hard-set has occurred. Concrete shall be cured by steam, moisture or by a curingcompound applied to all exposed surfaces. The process to cure the concrete for the timespecified on the drawings shall be continuous. At the conclusion of the curing period,cracks wider than 0.3 mm shall not be permitted at any point on the surface, other thancontrolled shrinkage cracks.

Sampling, testing and assessment of the strength of concrete shall be carried out inaccordance with AS 1379 or NZS 3112.

The tolerances that apply to cast in situ components shall be as given in Table 2.4.10(2).The tolerances that apply to precast components shall be as given as Table 2.4.10(3).


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TABLE 2.4.10(1)

COVER REQUIREMENTS FOR CONCRETE

Exposure classification(see Note 1)

Minimum cover for concrete strength(see Note 2)

(mm)

32 MPa 40 MPa 50 MPa

B1 40 30 25

B2 NA(see Note 3)

45 35

C NA(see Note 3)

NA(see Note 3)

50

NOTES:

1 Classification ‘A’ is not applicable due to aggressiveness of the site, e.g.fumes from vehicles or abrasiveness.

2 Negative tolerance on the fixing of reinforcement is not permitted.

3 NA denotes not applicable.

TABLE 2.4.10(2)

TOLERANCES FOR CAST IN SITU CONCRETE ELEMENTS

Item Tolerance(mm)

(a) General:(i) Placing of reinforcement(ii) Concrete cover

50 to +5

(b) Variation of cross-section −5 to +5

(c) Variation from vertical or specified batter 5 in 2.5 m (1 or 500)

(d) Variation from grades indicated on drawings 2.5 in 2.5 m (1 or 1 000)

(e) Departure from plan position at any level:(i) Parapets(ii) Relative displacement of adjoining components

25≤10

(f) Departure from alignment 5

(g) Irregularities 2.5 in 2.5 m

TABLE 2.4.10(3)

TOLERANCES FOR PRE CAST CONCRETE ELEMENTS

Item Tolerance(mm)

(a) General:(i) Placing of reinforcement(ii) Concrete cover

50 to +5

(b) Cross-section:(i) Dimension(ii) Out of square

0 to +3

(c) Squareness of ends (deviation from a placeperpendicular to the longitudinal axis)

≤3

(d) Overall length 3

(e) Profile in horizontal plane (bow) 3

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2.4.11 Plastic Plastics used in road safety barrier systems shall provide the following:

(a) Means to clearly identify the month and year of manufacture, or a method ofdetermining the remaining period for which the system shall be fit for use.

(b) Documentation on installation procedures to optimize the life of the plasticcomponent.

(c) Repair methods to be used where plastics are damaged.

(d) Data on the flammability of the plastics used and any special precautions necessaryto reduce the risks associated with fire.

(e) Disposal procedures at the end of the period for which the system shall be fit foruse.


2.4.12 Construction acceptance criteria for steel componentsSteel components shallbe erected in accordance with the drawings.

Metals that have less than 16% tested elongation shall not be used in elements subject toimpact by traffic, unless crash testing has shown that the material is acceptable. Allstructural steel shall comply with AS/NZS 3678 or AS/NZS 3679.1, as appropriate. Weldsshall be category SP in accordance with AS/NZS 1554.1 Welds subject to alternatingtensile or compressive stresses at 500 000 cycles or more shall comply withAS/NZS 1554.5.

Other metal materials, not specified herein, shall comply with the appropriate Australianor New Zealand Standard. If such a Standard is not available, they shall comply withSpecifications or Standards issued by bodies accredited by an authority, such as theAmerican Society for Testing and Materials (ASTM).

Steel railing shall be erected within the following tolerances:

(a) Departure from plan position. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mm.

(b) Departure from alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 mm.

(c) Irregularities in alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 mm in 3 m.

(d) Variation in joint gap width. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 mm.


2.4.13 Acceptance criteria At the end of installation, each road safety barrier systemshall be reviewed to ensure that the design expectations have been met. Issues to beaddressed shall include the following:

(a) Structural adequacy All components shall be installed in the right position. Bolts,cables and similar components shall be torqued, tensioned, or otherwise pre-loadedto the values specified by the manufacturer. Splices shall be checked to ensure theyare in the correct position with respect to traffic direction. Foundations shall bestructurally adequate for the imposed loadings, both horizontal and vertical.Products that require ballast shall be filled. Likely performance of the road safetybarrier system with respect to the design vehicle, its speed and its angle of impactshall be as specified.

(b) Terminals Leading and trailing terminals shall be in the correct position.Integrated anchorages shall be properly installed to provide the designed level ofresistance. Adequate recovery areas shall be provided behind gating terminals andshall be free from significant obstacles. Terminal offsets shall be in accordance withthe drawings.

(c) Functional adequacy Road safety barrier systems shall be installed at the rightheight with respect to the impacting vehicle adopted for the purposes of the design.

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Roadside furniture placed in front of the road safety barrier system, such as kerbs,shall not adversely affect the impact height. The leading and trailing points of needshall be properly located. Flare rates, where used, shall be appropriate. Workingwidth and dynamic deflection width requirements shall be met. The need forpedestrian rails shall also be considered.

(d) Interfaces All components of any transition, where fitted, shall be appropriate,continuous and in the right position. Bolts and similar hardware shall be tensionedto the values specified by the manufacturer.

(e) Site suitability Where anchors are an essential part of the road safety barriersystem, the site conditions shall be appropriate for the installation. Sight distanceshall remain appropriate. Delineation shall be appropriate and properly installed.General site safety issues shall be addressed, especially the needs of other roadusers.

After any roadwork activity in the vicinity of a road safety barrier system, a check shallbe made in accordance with Items (a) to (e) of this Clause.


2.5 MAINTENANCE AND DISMANTLING

NOTE: For commentary on this Clause, see Paragraph B2.5 of Appendix B.

2.5.1 General The following frequency of maintenance inspections of road safetybarrier systems shall be considered:

(a) The manufacturer’s specifications.

(b) The operating environment.

(c) The traffic volumes and composition.

(d) The risk at the sites.

During the maintenance inspection, an assessment shall be made of any changes that mayhave occurred which will alter the frequency of inspections required, or the elements to beinspected. Particular attention shall be given to any changes in the volume of traffic or itsspeed, and whether the vehicle adopted for the original design remains appropriate. Wherereverse direction crashes are a feature of the installation, an assessment shall be made toensure that the original design criteria remain valid.

2.5.2 Vandalism Special measures shall be provided where a road safety barriersystem is located in an area where vandalism is likely and risk management analysisshows that such measures are warranted. Issues such as damage by sharp objects orknives, drainage of any ballast, flammability, deliberate modification to increase thehazard and ease of removal of critical elements shall be taken into consideration. Thesurface shall resist damage from common solvents, especially petrol.

2.5.3 Cleaning Routine maintenance for removal of road grime and graffiti shall formpart of the documentation. In cases where particular solvents damage the road safetybarrier system, documentation on cleaning procedures shall be provided.

NOTE: Cleaning practices could affect the performance of the road safety barrier systembecause of the possibility that they may disable, or substantially reduce the effectiveness ofelements of the device, or cause corrosion that will lock up the system.

2.5.4 Ballast Where a road safety barrier system relies on ballast, such as water in thecase of plastic road safety barrier systems or sand in the case of barrel terminals, tofunction to the required test level, a means of determining whether sufficient ballast ispresent during a drive by inspection shall be provided.

Installations shall be checked for any unacceptable decrease in road safety, e.g. ballastspill onto the carriageway.

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2.5.5 General site maintenance The installation shall be examined to see whetherthere are site issues that have increased the risk of a collision with the device, or theseverity of such a collision. Particular attention shall be given to debris that may reducethe friction supply for other vehicles in the vicinity, or increase the hazard for pedestrians.

2.5.6 Dismantling Following any roadworks that change the vertical alignment of theroad, other works in the road corridor which alter the nature of hazards being protected,or other activities that modify the operating environment of the barrier system, a reviewshall be carried out to ensure that the need for the system remains and that themanufacturer’s operational specifications shall be complied with. The criteria specified inClause 2.4.13 may be used to make this assessment.

Dismantling of the road safety barrier system shall be in accordance with themanufacturer’s specifications.

NOTE: The manufacturer should be contacted if elements of the road safety barrier system areto be reused.

2.6 POST-CRASH ASSESSMENT AND REPAIR

NOTE: For commentary on this Clause, see Paragraph B2.6 of Appendix B.

2.6.1 General Before a road safety barrier system is installed, action plans shall beprepared for assessing and repairing the road safety barriers in case they are damaged.

Assessment of the damage to a road safety barrier system shall be undertaken as soon asis practicable after a crash. Crash sites shall not be left in a condition that increases therisk to other traffic to unacceptable levels. This shall be determined using risk analysistechniques.

2.6.2 Damage Road safety barrier systems shall permit the ready replacement of allelements that are damaged during a crash. As well, the replacement of components at theend of their design life shall be practicable and cost-effective.

2.6.3 Refurbishment Road safety barrier systems shall be inspected on a routine basisto identify incidental damage that has occurred in unreported crashes. Decisions to leavedamaged components in service shall be documented.

NOTES:

1 The document, which contains decisions to leave components in service, is to be preparedby people qualified to make such decisions about the road safety barrier system involved.

2 In general, the need to refurbish individual road safety barrier systems may be deferred toallow resources to be allocated to other road safety barrier systems that are judged to have ahigher priority.

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S E C T I O N 3 R I G I D R O A D S A F E T Y B A R R I E RS Y S T E M S

3.1 SCOPE This Section applies to road safety barrier systems that are designed sothat there will be no movement of the device, other than elastic strain, during a crashinvolving the design vehicle.

It includes road safety barrier systems that have rails, or similar components, that areattached to substantial bases which could be taken as elements of a rigid road safetybarrier system.

This Section also provides details of public domain systems that are deemed to complywith this Standard (both road safety barriers and interface arrangements).

NOTE: For commentary on this Clause, see Paragraph C3.1 of Appendix C.

3.2 GENERAL Proper consideration shall be given to selecting sites for rigid roadsafety barrier systems. Rigid road safety barrier systems shall only be installed atlocations where the hazard and risk associated with impacting the device are significantlyless than the hazard and the risk of impacting the items being protected.


3.3 DEVELOPMENT OF DESIGN


3.3.1 General The procedure for developing a design for a rigid road safety barriersystem shall be as follows:

(a) Determine the desirable outcome of the installations when it is impacted by thedesign vehicle at the nominated speed and impact angle. Pay particular attention tothe working width that is acceptable at the site.

(b) Undertake a risk analysis to determine the appropriate barrier performance level,(see Table 2.3.19), and thus the design vehicle, speed and angle of impact to satisfythe outcomes specified in Item (a).

(c) Select a rigid road safety barrier system that has been crash-tested to the appropriatetest level, or design a new road safety barrier system based on existing tested orproven barriers with only minor modifications, or design a new form of barrier andtest at the appropriate level in accordance with this Standard.

(d) Consider the likely outcome when the proposed road safety barrier installation issubjected to other crashes as specified in Clause 3.3.2.

(e) Repeat the process as necessary.

3.3.2 Other crashes In addition to the crash outcome associated with the designvehicle, the following issues shall be considered:

(a) Other crash vehicles Consider the outcome when the road safety barrier system ishit by a vehicle that is either lighter and lower, lighter and higher, or considerablyheavier and higher than the design vehicle.

(b) Other crash angles and speedsConsider the outcome when the impact angle of thedesign vehicle is larger than the nominated impact angle. The probable speedsassociated with these angles shall be used.

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3.4 ANALYSIS OF STRESSES IN RIGID ROAD SAFETY BARRIER SYSTEMSAnalysis shall be by a rational plastic analysis method (no load factors to be applied)unless other more rigorous analysis or crash testing methods are applied. The road safetybarrier shall resist the transverse longitudinal and bending moment loadings determinedfor the selected test level in accordance with Section 2. When impacted by the designvehicle at the specified speed and angle, destruction of elements of the system isacceptable. However, penetration is not acceptable.

Where the rigid road safety barrier system is placed on a structure, there shall besufficient resistance in the foundations to allow the failure mode to remain within the roadsafety barrier system. In the absence of a more rigorous analysis, the ratio between thestructural capacity of the foundation and the capacity of the rigid road safety barriersystem shall be not less than 1.2.


3.5 OTHER RESULTS Longitudinal road safety barrier systems shall be designed andconstructed to retain the idealized design vehicle for the particular site, e.g. car, truck orbus from rolling over the top of the road safety barrier system.

The height of centre of gravity of an impacting idealized design vehicle varies with thetype of vehicle and may be higher than the effective height of a road safety barriersystem. A vehicle will just roll over if the following condition applies:

. . . 3.5(1)Mo = malat (c − heff) − mg( b2

− ∆) − µmgheff 0

where

Mo = moment about contact point ‘0’ (see Figure 3.5)

m = mass of the vehicle, in tonnes

alat = lateral vehicle deceleration, in metres per second squared

≈ . . . 3.5(2)1.5 (ISx)

m

g = acceleration due to gravity, in metres per second squared

c = height of the vehicle’s centre of gravity above the ground, in metres(see Figure 3.5)

heff = effective height of the road safety barrier system above the ground, in metres(see Figure 3.5)

≥ . . . 3.5(3)

b = width of the vehicle, in metres (see Figure 3.5)

∆ = horizontal displacement of the road safety barrier system or rail, or both(between 0 and 0.3 m)

NOTE: For rigid concrete road safety barrier without steel rails, a value of 0 is to beused.

µ = coefficient of pavement friction (between 0 and 0.3)

NOTE: Recommended value of µ is 0.

ISx = kinetic energy of impacting vehicle expressed as xth percentile of the impactseverity, in kilojoules (see NCHRP 350)

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where

Flat = effective lateral force applied to the road safety barrier

hact = height of the road safety barrier system above ground, in metres

= heff + k

k = 0.05 m for rigid road safety barrier systems. For other barriers, e.g. semi- rigid andflexible, k shall be analysed

FIGURE 3.5 DIMENSIONS

3.6 RIGID ROAD SAFETY BARRIER PROFILE The profile of a rigid road safetybarrier system shall be either that shown to be acceptable by crash testing at design loadsor the deemed to comply type F shape or the vertical concrete barrier (VCB) type shape.Details of the type F shape shall be as shown in Figure 3.6(1). Details of the type VCBshape shall be as shown in Figure 3.6(2).

3.7 FOUNDATION The foundation of a rigid road safety barrier system shall be ofsufficient strength to resist both the shear forces and the bending moments applied duringa crash with the design vehicle. Depending on the nature of the road safety barrier system,some resistance to the vertical loads may be necessary.


3.8 COMBINATIONS OF RIGID ROAD SAFETY BARRIER SYSTEM AND RAILSYSTEM Metal posts and rail systems may be attached to the top of a rigid road safetybarrier system, provided the following requirements are met:

(a) The design shall incorporate a failure mechanism, which means that the anchors willbe the first point of failure followed by the posts and then the rail. The traffic faceof a rail shall be vertically aligned as shown in Figures 3.6(1) and 3.6(2), unlesscrash testing shows that other locations are acceptable.

(b) Rails shall be able to resist at least one third of the total horizontal impact.

(c) Rails shall be continuous and the capacity of any joints shall be at least 75% of therail.

(d) Posts shall be perpendicular to the top of type F or type VCB road safety barriers.

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DIMENSIONS IN MILLIMETRES

FIGURE 3.6(1) CONCRETE ROAD SAFETY BARRIER TYPE F(MEETS TEST LEVEL 3)


FIGURE 3.6(2) VERTICAL CONCRETE ROAD SAFETY BARRIER (VCB)(MEETS TEST LEVEL 3)

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3.9 PROXIMITY OF KERBS Rigid road safety barrier systems shall not be locatedadjacent to kerbs. Where this is not possible, kerbs shall be removed unless the distancefrom the face of the kerb is greater than—

(a) 1.5 m where the speed limit is 60 km/h or less;

(b) 2.1 m where the speed limit is 80 km/h; and

(c) 2.7 m where the speed limit is 100 km/h.

3.10 PROVISION FOR PEDAL CYCLISTS AND PEDESTRIANS Where there is awarrant to provide facilities for pedal cyclists or pedestrians, rails shall be provided inaccordance with Clause 2.3.13.

3.11 TERMINALS AND INTERFACE DETAILS Only tested details and devicesshall be used as terminals or to connect rigid road safety barriers to road safety barriersystems with different operating characteristics.

3.12 RIGID ROAD SAFETY BARRIER SYSTEMS IN PUBLIC DOMAIN Detailsof a design solution for type F and type VCB road safety barriers that are deemed tocomply shall be as shown in Figure 3.12(1) to Figure 3.12(9), as appropriate.

Details of a connection between a non-rigid and a rigid road safety barrier system that aredeemed to comply shall be as shown in Figure F5 and Figure F6 of Appendix F.

Details of a connection, including details of a slotted terminal, between a non-rigid and arigid road safety barrier system that are deemed to comply shall be as shown inFigures F7, F 8 and F9 of Appendix F.


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NOTES:

1 Details of the installation of the foundation are indicative only.

2 Units are to be connected at the top of the barrier to obtain the 150 kN force specified in Clause 2.3.6.


FIGURE 3.12(1) PROFILE TYPE 1 IN SITU(MEETS TEST LEVEL 3)

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NOTES:




FIGURE 3.12(2) PROFILE TYPE 2 IN SITU(MEETS TEST LEVEL 3)

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NOTES:1 Details of the installation of the foundation are indicative only.2 Structural reinforcement is to be provided throughout the full height of the section where the

difference in level between two carriageways requires it.3 Additional reinforcement is to be provided where necessary.4 Units are to be connected at the top of the barrier to obtain the 150 kN force specified in Clause 2.3.6.


FIGURE 3.12(3) PROFILE TYPE 3 IN-SITU SPLIT LEVEL(MEETS TEST LEVEL 3)

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NOTES:




FIGURE 3.12(4) PROFILE TYPE 4 PRECAST UNITS INSTALLED(MEETS TEST LEVEL 3)

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NOTES:

1 For manufacturing tolerances, see Clause 2.4.



FIGURE 3.12(5) PRECAST 3 m STANDARD LENGTH UNIT(MEETS TEST LEVEL 3)

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NOTES:

1 B and C bars shall be placed alternately, i.e. B and C bars are 150 mm apart.

2 Minimum 28-day compressive strength of concrete is to be 30 MPa.

3 Clear cover to reinforcement nearest to the concrete surface is to be 30 mm if no dimension shown.

4 Steel reinforcement shall be Grade 400Y in accordance with AS 1302.

5 This figure shows the bridge railing only, not the design or detailing of the bridge deck. Onlyreinforcement directly related to the bridge rail is shown. Bridge decks should be designed to developthe full strength of the bridge railing.

6 Where rails are provided on top of these barriers for additional crash protection, they are to be alignedwith the traffic face of the wall at the top.

Where the rails provided are not for crash purposes, i.e. rails for pedal cyclists and pedestrians, thenthese rails may be set back from the traffic face.

7 Longitudinal bars (A bars) should be spliced for a minimum length of 750 mm with the splices beingstaggered so not more than 50% of bars are spliced in any one cross-section.

8 A road safety barrier is deemed to comply at test level 3.


FIGURE 3.12(6) 820 HIGH VCB ROAD SAFETY BARRIER SYSTEM

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NOTES:










FIGURE 3.12(7) 820 HIGH TYPE ‘F’ ROAD SAFETY BARRIER SYSTEM

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NOTES:

1 B and C bars shall be placed alternately, i.e. B and C bars are 150 mm apart.










FIGURE 3.12(8) 1100 HIGH VCB ROAD SAFETY BARRIER SYSTEM

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NOTES:










FIGURE 3.12(9) 1100 HIGH TYPE ‘F’ ROAD SAFETY BARRIER SYSTEM

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S E C T I O N 4 N O N - R I G I D R O A D S A F E T YB A R R I E R S

4.1 SCOPE This Section sets out the requirements for non-rigid road safety barriersystems in terms of the following:

(a) Development of designThe design of non-rigid road safety barrier systems forparticular impact conditions including preparation of the specification for theinstallation of non-rigid road safety barrier systems.

(b) Installation The installation of non-rigid road safety barrier systems.

(c) In-service inspection, maintenance and disposalThe inspection, maintenance anddisposal of in-service non-rigid road safety barrier systems.

(d) Systems developmentThe development of new types of non-rigid road safetybarrier systems.

This Section also contains details of selected public domain non-rigid road safety barriersystems that are deemed to comply with this Standard.

NOTE: For commentary on this Clause, see Paragraph D4.1 of Appendix D.

4.2 DESIGN OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS Theprocedure for the development of the design for a non-rigid road safety barrier systemshall be as follows:

(a) Determine the range of vehicle impacts to be provided for the specific location.

(b) Determine the test level of the non-rigid road safety barrier system required toprovide the protection as specified in Step (a).

(c) Determine the desirable outcomes from the installation when impacted by the rangeof vehicles at the nominated speed and impact angle, particularly dynamic deflectionand working width, and by the range of unprotected road users.

(d) Select the type of non-rigid road safety barrier system to be used for the particularlocation.

(e) Design a draft layout of the non-rigid road safety barrier installation.

(f) Undertake a risk analysis to determine whether the risk is appropriate at the site.

(g) Repeat the process as necessary.

(h) Prepare the specification.

4.3 INSTALLATION Prior to installing a non-rigid road safety barrier system, the siteshall be inspected to determine whether—

(a) the proposed type of road safety barrier system and its layout are still appropriate;

(b) the planned type of road safety barrier system or its layout, or both, requiresmodification; or

(c) the installation of the road safety barrier system is to be aborted.

NOTE: For commentary on this Clause, see Paragraph D4.3 of Appendix D.

4.4 DEVELOPMENT OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS

4.4.1 General All non-rigid road safety barrier systems shall comply withClause 4.4.2. Non-rigid road safety barrier systems with tensioned wire ropes shallcomply with Clause 4.4.3.

NOTE: For commentary on this Clause, see Paragraph D4.4.1 of Appendix D.

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4.4.2 All non-rigid road safety barrier systems

4.4.2.1 Intended function The following shall be determined when developing non-rigidroad safety barrier systems:

(a) The test level (see Section 2) that is being addressed.

(b) The essential mode of operation of the road safety barrier system. If the mode issignificantly changed when the impacts are more severe, then all modes shall bespecified.

(c) Whether the road safety barrier system is to embody wire-rope elements.

(d) The manner in which the road safety barrier system is to be terminated and, ifappropriate, the manner in which the road safety barrier system is to be transitionedto rigid road safety barrier systems or structures.

(e) The range of physical environments in which the road safety barrier system iscapable of being used.

NOTE: For commentary on this Clause, see Paragraph D4.4.2.1 of Appendix D.

4.4.2.2 Practical usefulness For the practical usefulness of non-rigid road safety barriersystems, ensure that—

(a) appropriate crash-safe methods shall be available for terminating the non-rigid roadsafety barrier systems and for the changeover from non-rigid road safety barriersystems to more rigid road safety barrier systems and to structures; and

(b) the non-rigid road safety barrier systems shall cater for the existence of commonsite conditions.

Documentation of how the non-rigid road safety barrier systems interact with common siteconditions shall be made available.


4.4.3 Non-rigid road safety barrier systems with tensioned wire ropes

4.4.3.1 Rope construction The rope construction shall be such that individual wires donot fracture nor develop sharp edges.

4.4.3.2 Rope tension, anchorage and tension devicesThe design of the non-rigid roadsafety barrier system including rope anchorage, tension devices and the manufacturingprocess for the whole system shall be as follows:

(a) The ropes shall develop and maintain the specified tension along the full length ofthe road safety barrier system, until the occurrence of an impact.

(b) A sudden release of tension in the rope shall be prevented if one particulartensioning device is released whilst leaving the other tensioning devices fullytensioned.

(c) All the components of the non-rigid road safety barrier system shall remain in theircorrect location relative to each other.


4.4.3.3 Rope diameter The diameter of tensioned ropes shall be not less than 19 mm.


4.4.3.4 Rope manufacture Ropes and the wire from which the rope is made, shall bemanufactured in accordance with the appropriate Australian or New Zealand Standards.

4.4.3.5 Use of non-rigid road safety barrier systems in corrosive or abrasiveenvironments If it is intended to use non-rigid road safety barrier systems in corrosive orabrasive environments, the design shall be such as to—

(a) ensure that the wire ropes, associated anchorages and tension devices do not failprematurely or catastrophically due to corrosion or abrasion; and

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(b) enable easy inspection of the wire ropes, associated anchorages and tension devicesso as to determine the extent and significance of any corrosion and abrasion.

4.4.3.6 Documentation The documentation shall, in the case of non-rigid road safetybarrier systems with tensioned wire ropes, pay particular attention to—

(a) wire ropes, associated tension devices and anchorages; and

(b) corrosion and abrasion.

4.5 PUBLIC DOMAIN NON-RIGID ROAD SAFETY BARRIER SYSTEMS

4.5.1 General Public domain non-rigid road safety barrier systems shall be as given inTable 4.5.1. Details of the non-rigid road safety barrier systems, their assembly andspecification of their parts are shown in the relevant figures of Appendix F. The publicdomain non-rigid road safety barrier systems shall be deemed to comply with therequirements of test level 3.


4.5.2 Area between traffic lane and non-rigid road safety barrier systems The areabetween the traffic lane and the front face of the non-rigid road safety barrier system shallbe a plane, trafficable surface with a cross-fall less than or equal to 1 in 10. The areafrom the face of the road safety barrier to the full extent of the working width shall be inaccordance with the manufacturer’s specification.


4.5.3 Location and orientation of steel blockouts, posts and nailing lapsSteelblockouts and posts shall be located and orientated so as to minimize any potential forerrant vehicles, or all other road users, to snag on that open face or by the laps of rails.


4.5.4 Foundation posts on natural ground The foundation posts shall be such that ifthe non-rigid road safety barrier system is subjected to a design impact, the full bendingstrength of the posts is developed and the posts yield approximately 75 mm below theground line.

Where a post is to be installed into a bound pavement layer, in very stiff clay or inconcrete, the procedure shall be as follows:

(a) Excavate or pre-bore a hole in the ground at least 400 mm in diameter with the holediameter extending at least to within 300 mm of the bottom of the post.

(b) Locate the post in the hole so that either the post will be positioned centrally in thehole, or be closer to the side of the hole further from the traffic lane from whichmost errant vehicles will originate.

(c) Backfill around the posts with clean, well-graded, non-cementitious granularmaterial, compacted so that—

(i) if a horizontal force of 1 kN is applied in any direction to within the top200 mm of a post before the rail is secured, movement of the post at groundlevel will not exceed 3 mm; and

(ii) inservice, the backfill around the posts does not settle nor does the backfill‘arch’, nor do voids form within the backfill.


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4.5.5 Anchorage of the W-beam or thrie-beam The W-beam or thrie-beam shall beanchored at both ends of the non-rigid road safety barrier system installation in such amanner that the full tension of the W-beam or thrie-beam can be developed if the non-rigid road safety barrier system is hit by a vehicle one panel from the end of theinstallation. Where cable terminals are used, the nuts at both ends of each cable shall betightened to 50 Nm.


4.5.6 Fixing of the W-beam or thrie-beam to the blockouts The W-beam or thrie-beam shall be attached to the blockouts as shown in the relevant figures of Appendix F.


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TABLE 4.5.1

TYPES OF PUBLIC DOMAIN NON-RIGID ROAD SAFETY BARRIER SYSTEMS

TypePost

spacing(m)

Dynamicdeflection

(m)Remarks

Index to standard component drawings inAppendix F

Item Figure

G4 2.0 1.0(2 000 kg vehicleat 100 km/h; and25°)

(a) W-beam steel rail system(b) Anchored terminals are essential

W-beam and stiffenerC-postBlockoutSplice bolt and nutBolt and nut (nail to post)Block bolt and nutW-beam structure connector

F12F16F21F36F36F37F27

G9 2.0(seeItem (c))

0.6(2 000 kg vehicleat 100 km/h; and25°)

(a) Thrie-beam steel rail system(b) Can be used with G4 system with

W-thrie transition beam(c) Anchored terminals are essential

Thrie-beam and stiffenerC-postBlockoutW-thrie transition beamThrie-beam structureconnectorSplice bolt and nutPost bolt and nutBlock bolt and nut

F14F17F23F15F27

F36F36F37

G9(Modified)

2.0 1.0(8 000 kg vehicleat 100 km/h; and15°)

(a) Thrie-beam steel rail system withmodified blockout

(b) Can be used with G4 system withW-thrie transition beam

(c) Anchored terminals are essential

Thrie-beam and stiffenerC-postModified blockoutW-thrie transition beamThrie-beam structureconnectorSplice bolt and nutPost bolt and nutBlock bolt and nut

F14F17F23F15F27

F36F37F37

MB4 2.0 0.5(2 000 kg vehicleat 100 km/h; and25°)

(a) W-beam steel rail median system(b) Anchored terminals are essential

W-beam and stiffenerC-postBlockoutSplice bolt and nutPost bolt and nutBlock bolt and nut

F12F21F16F36F36F37

(continued)

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47 AS/NZS 3845:1999

TABLE 4.5.1 (continued)

TypePost

spacing(m)

Dynamicdeflection

(m)Remarks


Item Figure

MB9(Modified)

2.0 0.5(2 000 kg vehicleat 80 km/h and25°

(a) Thrie-beam steel rail median systemwith modified blockouts

(b) Can be used with MB-4 system withW-thrie transition beam

(c) Anchored terminals are essential

Thrie-beam and stiffenerC-postModified blockoutSplice bolt and nutPost bolt and notBlock bolt and nut

F14F17F23F36F36F37

Modified eccentric loader terminal(MELT) 8.0 m

NA (a) Gating terminals for general use withG4 W-beam system (both loadingand trailing)

(b) Can be used with G9 and G9(modified) thrie-beam system

(c) Batter slope to be traversable andfree from fixed object hazards

(d) Flare is critical(e) Use as trailing terminal when barrier

is within clear zone of opposingtraffic

General arrangement drawingW-beam end railsTimber postsSteel blockoutStrut and yoke assemblyShelf angleSoil tube and plateBuffered end section anddiaphragm

Anchor plateCable assemblyPost sleeveBearing plateSplice bolt and nutPost bolt and nutRectangular washerYoke bolt and nutSoil plate bolt and nutAnchor plate bolt and nut

F11F13F19F21F32F31F30F25

F29F33F34F35F36F37F39F38F38F36

(continued)

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AS/NZS 3845:1999 48

TABLE 4.5.1 (continued)

TypePost

spacing(m)

Dynamicdeflection

(m)Remarks


Item Figure

Trailing terminal(TT) 4.0 m

NA (a) Trailing terminal for general usewith G4 W-beam system

(b) Can be used with G9 and G9(modified) thrie-beam system using atransition to G4

(c) Batter slope to be reasonablytraversable and free from fixedobject hazards

(d) Systemnot to be used within clearzone of opposing traffic

General arrangement drawingW-beam end railC-postBlockoutEnd postSoil plateShelf angleBuffered end sectionAnchor plateCable assemblyBearing plateSplice bolt and nutPost bolt and nutRectangular washerSoil plate bolt and nutAnchor plate bolt and nut

F10F13F17F21F18F30F31F25F29F33F35F36F37F39F38F36

Structure transition6.0 m

NA Transition system for barrier designs G4and G9 (modified) to rigid structures suchas type F concrete barriers and bridgeparapets

General arrangement drawingThrie-beamC-postBlockoutW-thrie transition beamC-postBlockoutStructure connectorSplice bolt and nutPost bolt and nutBlock bolt and nut

F10F14F17F23F15F16F21F27F36F36F37

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49 AS/NZS 3845:1999

S E C T I O N 5 T E S T I N G

5.1 SCOPE This Section covers the following types of tests:

(a) Certification of new systems.

(b) Performance validation of existing road safety barrier systems following changes incomponents.

(c) Verification of performance of a road safety barrier system due to site specificissues, such as kerbs and drainage ditches in front of or within the working area ofthe road safety barrier system, and specific application requirements, such as postsin saturated ground.

5.2 GENERAL NCHRP Report 350 shall be the basis of testing procedures. However,to meet some specific applications in Australia and New Zealand, the requirements ofNCHRP 350 have been modified by the addition of a lower test level (TLO), as specifiedin Clause 5.3.

With the exception of Item (c) of Clause 5.1, test procedures shall not be designed toreplicate any specific set of circumstances. Rather, the tests shall be arranged so that theyprovide a representation of an average set of circumstances, in terms of ground support,temperature conditions and vehicle types.

NOTE: This recognizes that the number of variables in a crash test of a road safety barriersystem can be high and performance can only be gauged when as many factors as possible arekept sensibly constant.

5.3 MODIFICATIONS TO NCHRP 350

5.3.1 Chapter 1 There are no modifications to Chapter 1, Introduction, ofNCHRP 350.

5.3.2 Chapter 2 The modifications to Chapter 2, Test Parameters, of NCHRP 350 shallbe as given in Table 5.3.2(1).

TABLE 5.3.2(1)

MODIFICATIONS TO CHAPTER 2 OF NCHRP 350

NCHRP 350Clause

Heading Modifications

2.1 General No change

2.2 Testing Facility No change

2.3 Test Article Delete Clause 2.3.2.4

2.4 Test Vehicles (a) Add 1 600C vehicle, as given inTable 5.3.2(2) of this Standard, toTable 2.1 in NCHRP 350

(b) Delete Clause 2.4.1.3

2.5 Surrogate Occupants No change

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TABLE 5.3.2(2)

PROPERTIES OF 1600C TEST VEHICLE

Property 1 600C

Mass (kg)Test inertialDummyMaximum ballastGross static

1 600 ±4575

1601 675 ±45

Dimensions (mm)WheelbaseFront overhandOverall lengthTrack width

2 800 ±100950 ±100

4 800 ±2001 500 ±200

Centre of mass location (mm)

Aft of front axleAbove ground

1 250 ±150550 ±50

Location of engine Front

Location of drive axle Rear

Type of transmission Manual or automatic

5.3.3 Chapter 3 The modification to Chapter 3, Test Conditions, of NCHRP 350 shallbe as given in Table 5.3.3(1). References to support structures, breakaway utility polesand truck-mounted attenuators shall be deleted.

TABLE 5.3.3(1)


NCHRP 350Clause

Heading Modification

3.1 General Add 1 600C vehicle

3.2 Test matrices Add Tables 5.3.3(2) and 5.3.3(3) ofthis Standard to Tables 3.1 and 3.2of NCHRP 350

3.3 Tolerances on impact conditions Add 1 600C vehicle, as given inTable 5.3.3(4) of this Standard, toTable 3.5 of NCHRP 350

3.4 Impact point for redirectivedevices

No change

3.5 Side impact tests No change

TABLE 5.3.3(2)

ADDITION TO TABLE 3.1 OF NCHRP 350TEST MATRIX FOR LONGITUDINAL BARRIERS

Testlevel

Barriersection

Testdesignation

Impact conditionsImpactpoint

Evaluation criteria(see Table 5.3.2(1))Vehicle

Nominal speed(km/h)

Nominal angle(deg)

0 Length of need 1-101-12

820C1 600C

5050

2025

(b)(b)

A, D, F, K, MA, D, F, K, M

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TABLE 5.3.3(3)

ADDITIONS TO TABLE 3.2 OF NCHRP 350TEST MATRIX FOR TERMINALS AND CRASH ATTENUATORS

TestLevel

FeatureFeature

typeTest

designation

Impact conditionsImpactpoint

Evaluation criteria(see Table 5.2.2(1))Vehicle

Nominalspeed(km/h)

Nominalangle(deg)

0

Terminals andredirective crash

attenuators

G or NG 1-30 820C 50 0 (b,e) C,D,G,K,N

G or NG S1-30a 700C 50 0 (b,e) C,D,G,K,N

G or NG 1-31 1 600C 50 0 (b) C,D,G,K,N

G or NG 1-32 820C 50 15 (b) C,D,G,K,N

G or NG S1-32a 700C 50 15 (b) C,D,G,K,N

G or NG 1-33 1 600C 50 15 (b) C,D,G,K,N

G 1-34 820C 50 15 (b,e) C,D,G,K,N

G S1-34a 700C 50 15 (b,e) C,D,G,K,N

G 1-35 1 600C 50 20 (b) A,D,G,K,L,M

NG 1-36 820C 50 15 (b) A,D,G,K,M

NG S1-36a 700C 50 15 (b) A,D,G,K,M

NG 1-37 1 600C 50 20 (b) A,D,G,K,L,M

NG 1-38 1 600C 50 20 (b) A,D,G,K,L,M

G or NG 1-39 1 600C 50 20 (b) C,D,G,K,L,M,N

Non-redirectivecrash

attenuators

G 1-40 820C 50 0 (e,h) C,D,G

G S1-40a 700C 50 0 (e,h) C,D,G,K

G 1-41 1 600C 50 0 (h) C,D,G,K

G 1-42 820C 50 15 (h) C,D,G,K,N

G S1-42a 700C 50 15 (h) C,D,G,K,N

G 1-43 1 600C 50 15 (h) C,D,G,K,N

G 1-44 1 600C 50 20 (h) C,D,G,K,N

TABLE 5.3.3(4)

ADDITION TO TABLE 3.5 OF NCHRP 350IMPACT SPEED AND ANGLE TOLERANCES

VehicleSpeed tolerance

(km/h)Angle tolerance

(deg)

1 600C ±4.0 ±1.5

5.3.4 Chapter 4 The modifications to Chapter 4, Data Acquisition, of NCHRP 350shall be as given in Table 5.3.4(1).

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TABLE 5.3.4(1)


NCHRP 350Clause


4.1 Typical parameters No change

4.2 Pretest parameters Add 1 600C vehicle to anylisting of ‘C’ vehicles

4.3 Test parameters No instrumentation is requiredon the 1 600C vehicle for testlevel 0

Table 4.1 of NCHRP 350 hasthe measurements of workingwidth added as given inTable 5.3.4(2) of this Standard

4.4 Post-test parameters No change

4.5 Additional parameters No change

TABLE 5.3.4(2)

ADDITION TO TABLE 4.1 OF NCHRP 350KEY TEST PARAMETERS

ParameterRecommendedmeasurement

tolerance

Acceptablemeasurement

techniqueRemarks

Maximum transversedisplacements of vehicle bodybeyond face of barrier at point

of maximum dynamic deflection

±5.0 cm High speed cine

Minimum film speedof 200 frames/secoverhead camera

5.3.5 Chapter 5 There are no modifications to Chapter 5, Evaluation Criteria, ofNCHRP 350.

5.3.6 Chapter 6 The modifications to Chapter 6, Test Documentation, of NCHRP 350shall be as given in Table 5.3.6.

TABLE 5.3.6


NCHRP 350Clause


6.1 General reporting recommendations Add 1 600C vehicle to the700C and 850C vehicles

6.2 Electronic data Not applicable

5.3.7 Chapter 7 There are no modifications to Chapter 7, Implementation and In-Service Evaluation, of NCHRP 350.

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APPENDIX A

BACKGROUND INFORMATION

(Informative)

Road safety barrier and crash attenuator systems are installed on the verges of roads toreduce the hazards associated with road use. These systems can be installed on apermanent or temporary basis.

There are a limited number of ways in which road barrier safety systems can operate.However, all systems attempt to dissipate the kinetic energy of a vehicle crash by one ormore of the following mechanisms:

(a) Heat through friction.

(b) Elastic movement of the device or components of the vehicle, or both.

(c) Plastic deformation of portions of the device or the vehicle, or both.

(d) Fracture of elements of the device or the vehicle, or both.

(e) Physical displacement of the device or the vehicle, or both, such as lifting thevehicle.

By installing devices that dissipate large amounts of kinetic energy by the mechanismsspecified in Items (a) to (e), considerable care should be taken to ensure that the energytransfer does not occur in unexpected or uncontrolled ways, or both. For instance,unintended snagging of the vehicle on an element of the system can cause violent rollingand yawing, which may result in severe injuries to vehicle occupants. Road safety barriersystems that fail to control the exit path may unnecessarily involve nearby vehicles in acrash.

The provision of appropriate systems that substantially reduce the level of hazard on aroad only occurs when there is a close communication and a cooperative approachbetween the owner of the device and those who have the responsibility for specifying,manufacturing, constructing, maintaining and repairing the device, and road users.Without effective communication between these parties, there is the distinct possibilitythat the installation may not perform in the manner intended. In some circumstances, theinstallation may increase the hazard. It is intended that all parties involved in theprovision of the devices communicate effectively to ensure that there is real reduction inthe roadside hazard for all users.

It is expected that owners of these devices will have a realistic understanding of a likelyperformance associated with installing a particular system at the site in question. It shouldnot be expected that the system will provide complete protection over the wide range ofvariables that could apply in a crash, such as vehicle mass, dimensions, speed andorientation of the vehicle on impact. It should also be recognized that the system itselfintroduces a hazard to the travelling community. It should be ensured that the systemselected provides the community with an investment that improves safety at the site andan appropriate balance with the need for investment in such systems on the rest of theroad network.

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Models that accurately predict the behaviour of vehicles in crashes with these devices arebeing developed. Until such models mature, full-scale crash testing is the best way toproperly evaluate the performance. Yet, even crash testing raises questions about detailsof the test procedures adopted, the type of vehicles selected for the test and theapplicability of the results to a particular site. Testing is not meant to replicate anyparticular crash condition. Rather, it provides points on a continuum of energy dissipationwhich provides a guide as to the likely performance of a particular safety barrier systemat a particular site if impacted by any of the range of vehicles of various masses anddimensions, travelling at a range of possible speeds that would be a feature of thelocation.

The technical documentation supporting a road safety barrier system should also includedetails that will enable a maintainer, a specifier or a member of the public to confirm thatan installation is in conformance with the manufacturer’s specification.

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APPENDIX B

COMMENTARY ON SECTION 2

(Informative)

B2.1 SCOPE Great care should be exercised in selecting the sites to install, repair orto replace a road safety barrier system and in selecting the type of system to be used.

This Standard has been developed on the basis that practitioners will be using ‘riskmanagement’ techniques to make informed choices about selecting the sites. Details ofrisk management techniques are contained in AS/NZS 4360. However, Simon Chapman,Associate Professor of Public Health and Community Medicine at the University ofSydney has cautioned experts when applying risk management techniques. He is of theopinion that there is a tendency for experts to systematically overestimate the risk whenthe hazard is high and underestimate the risk when the hazard is low. Chapman points outthat the community tends to focus on ‘outrage’. Outraged people pay little attention toscientific data; the media find outrage more news worthy than statistics. A climate ofoutrage thus overestimates the risk when the outrage is high and underestimates the riskwhen outrage is low.

Some issues that have to be considered when assessing whether outrage may be an issueinclude the following:

(a) Voluntary risk versus coerced riskOutrage is higher when people are forced totake a risk instead of accepting the risk by their own volition.

(b) Natural risk versus industrial risk The community may be more upset byinstallations that are built, such as a road safety barrier, than hazards that naturallyoccur, such as trees on the side of the road.

(c) Familiar risk versus exotic risk New devices (exotic) are treated more suspiciouslythan familiar installations.

(d) ‘Not dreaded’ risk versus ‘dreaded risk’Some issues have generated aniconography in literature that instil dread in people. Nuclear radiation is an obviouscase.

(e) Chronic risk versus catastrophic riskCommunities fear low probability, highmagnitude risk more than high probability low magnitude risk. Bus crashes are morefeared than car crashes.

(f) Knowable risk versus not knowable riskThe potential for dread can often beincreased when the issues are hard to understand.

(g) Morally irrelevant risk versus morally relevant riskThe community tends to havetolerance for outrage-inducing problems where the issue is seen as morallyirrelevant.

With respect to the type of road safety barrier system to be selected, this Standard doesnot attempt to make any comparison between the systems available. The variety ofexisting systems, and the number of new systems that are becoming available, wouldmake this impractical. However, the crash test results required to be provided as part ofthis Standard should be used to assist in the selection. But crash testing is only part of theprocess necessary to provide an effective road safety barrier system on the road. A climateof open communication between the parties involved (from designer to erector) is pivotal.This is particularly necessary at sites where a road safety barrier system is required tooperate near the operating boundaries of any one of the many parameters that affectperformance.

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With respect to current installation, the wide variation in type, age and general conditionof road safety barrier systems should be noted. The intention of this Standard is not tocreate a demand to remove all examples of superseded practice from the roadside. It isanticipated that equipping the road network with road safety barrier systems that complywith this Standard will take many years to achieve. It is essential that due thrift beexercised in meeting the large number of competing demands for scarce resources.Instead, a rational analysis of the hazards and the risks should be used to identify siteswith the highest need and ensuring that these sites are addressed first.

It should also be noted that regular reviews are part of the normal management cycleassociated with a Standard. During the period that will elapse before a review of thisStandard occurs, there will be many advances in technology, changes in the Australianand New Zealand vehicle fleet and changes in community expectations. In applying thisStandard, it is expected that these issues will be recognized.

B2.2 GENERAL

B2.2.2 Site information The proposed location for a new road safety barrier may—

(a) interfere with a utility service, drainage conduit or structure during installation ofposts, excavation for elements of the road safety barrier system, and the like;

(b) be so close to conduits, or some structure, which might be damaged as a result of—

(i) movement of the elements of the road safety barrier system when it is hit bya vehicle; or

(ii) removing or replacing elements after the road safety barrier system has beenhit by a vehicle;

(c) involve interference with the road safety barrier system, its footings, anchorages, oralter the support of the footings or anchorages during inspection or repair of theconduit or structure; and

(d) be through part of an embankment that contains a conduit around which thesurrounding ground has arched or voided.

The information regarding the general site details and the type of vehicle that will be usedfor design purposes requires personal inspection by the designer. The nature of the hazardbeing protected is to be verified. This will allow a realistic assessment about the hazardposed to traffic should it be left unprotected. A road safety barrier system is oftenassociated with a considerable length of installation. Whilst the severity of impacting theroad safety barrier system may be less than hitting the hazard being protected, the lengthof the device may increase the risk of a crash. This trade-off is to be carefully assessed.

The recovery area available to vehicles becomes crucial in any decision associated withthe installation of a road safety barrier system. Preferred practice is to have the devicelocated as far away from the traffic lanes as is possible. This is subject to the dynamicdeflection and working width being available. However, the further away the installationis from the road, the higher is the likely angle of the impact. Accordingly, it can beinappropriate to have rigid road safety barrier systems located more than four metres fromthe lanes. The crash performance of rigid road safety barrier systems is often better whenthey are in close proximity to traffic, but not closer than the offsets specified elsewhere.

The site inspection is also necessary to assess the likely vertical trajectory of an impactingvehicle on the system. This issue is crucial to the satisfactory performance under thedesign conditions.

The outcomes associated with impacts by the design vehicle travelling at higher speeds,impacting at higher angles, or both, should also be assessed together with theconsequences of a vehicle being heavier than the design vehicle impacting the device.

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B2.3 DESIGN AND DOCUMENTATION

B2.3.1 General The process of selecting the appropriate road safety barrier systemonly follows when the objectives are clearly defined and the limitations understood. Theoutcome at a particular site should be decided after the following are taken into account:

(a) The needs ofall road users are properly taken into account.

(b) The road safety barrier system selected is appropriate for the speed and trafficcomposition at the site.

(c) The approach to the road safety barrier system means that the crashing vehicle hitsat the appropriate height.

(d) The foundations provide the required support to the road safety barrier system.

(e) Due regard is taken of the environmental conditions that exist at the site.

(f) Short-term installations are in accordance with the specification and, whereappropriate, comply with either AS 1742.3 or the appropriate guidelines publishedby TRANSIT New Zealand.

(g) Specifiers evaluating their site conditions need to consider the manufacturer’sguidelines and recommendations.

For road safety barrier systems, the following criteria apply:

(i) Road safety barrier systems are considered as a unit, particularly with respect totransitions between systems with different characteristics.

(ii) Appropriate terminals are specified at both the leading and trailing ends.

(iii) Road safety barrier systems are to be located as far away from the traffic lanes as ispracticable.

(iv) The desirable minimum offset from a traffic lane is 500 mm, but not less than250 mm.

For crash attenuators, the following criteria apply:

(A) Gating systems are only used at appropriate locations.

(B) Where reverse direction impacts are likely, the system performance is acceptable.

(C) The period of disablement is appropriate for the site. Once it is being decided that aroad-side safety barrier system is warranted, the specific type of system is to beselected. The selection process is complex as there are many variables and some ofthe performance criteria are subjective.

The most desirable road safety barrier system is usually one that offers the requireddegree of shielding at the lowest total cost. These costs include those incurred by theagency that owns the road safety barrier system, those borne by the road users involved inthe crash and the costs to those who may live in close proximity to the road safety barriersystem and whose amenity will be affected by the erection of a system.

Elements that have to be considered include the following:

(1) Performance The road safety barrier system is to be structurally able to containand redirect the nominated design vehicle.

(2) Deflection The dynamic deflection and the working width required by the roadsafety barrier system should not exceed the space available.

(3) Site conditions The slope, the condition of the terrain on the approach to the roadsafety barrier system and the distance from the travelled way may preclude the useof some types of installations.

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(4) Compatibility The road safety barrier system has to be capable of being changedover to any other systems being used at the site, such as connection to a bridgerailing.

(5) Costs The appropriate investment costs are made. It is generally preferable to havelonger lengths of low-cost protection than very short lengths of high-cost devices.

(6) Maintenance Non-rigid road safety barrier systems generally require moremaintenance than rigid systems. Standardization of system types brings obviousadvantages with respect to components storage, training of field personnel inerection and maintenance practices and the like. Simple designs often prove moreeffective than the complex installations.

(7) Aesthetics The compatibility of the road safety barrier system with its surroundscan be an important selection criteria.

(8) Sight distance At some sites, the requirement to see through or across theinstallation may eliminate some road safety barrier systems from being considered,particularly at intersections or on horizontal curves with a small radius.

B2.3.2 Operational temperature range For the design of road safety barrier systems,issues such as heat, snow, ice and wind should be taken into consideration, as appropriate.Matters that are to be addressed include the following:

(a) The increased risk of incidental impacts, particularly under icy conditions.

(b) The build-up of snow or debris, or both, by some configurations of road safetybarrier systems.

(c) The methods used for clearing the road of drift and debris.

(d) The consequences of shadow on the carriageway lanes.

(e) Surface temperatures are usually much higher than 50°C and in the case of plasticcomposites this could affect the material especially if painted a dark colour.

(f) Allowances for the expansion and contraction forces that may be generated.

B2.3.3 Environment The effects of dust, corrosion or similar environmental factorsthat would reduce the effectiveness of the road safety barrier system during its design lifehave to be considered. Matters to be addressed include the likely changes in theperformance of the road safety barrier system such as the ‘lock up’ of elements due tocorrosion or due to dust. The increased potential for such problems, for example, at siteswith a marine environment or at sites subjected to high levels of industrial fumes or dust,has also to be considered. Where special features are necessary to cope with particularlyadverse environmental circumstances such as marine locations or sites where snow occurs,or where there are critical elements that may undergo disabling property changes beforethe end of the span of life of the road safety barrier system, such as plastic elementssubjected to high UV exposure or any chemical used to maintain the road safety barriersoperational, such as antifreeze for water-filled plastic road safety barriers in sub-zeroconditions, then these are to be clearly detailed.

B2.3.4 Flooding If road safety barrier systems are to be constructed at locations thatare subject to inundation at an ARI of 20 years, or lesser events, the road safety barriersystem is to withstand both the hydrodynamic forces and any loads from waterbornedebris. The road safety barrier system should also allow for the rapid removal of debrisand for the cleaning of the road safety barrier system. For larger flood events, it isacceptable for the devices to be rendered unusable by floodwater. An inspection should bemade before the road is re-opened to general traffic following any flood that could affectthe system.

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B2.3.5 System details The following should be taken into consideration:

(a) Impact The possible crash events at a site and the range of possible outcomes forimpacts by all types of road users should be clearly identified. Traditionally, mostroad safety barrier systems have been tested with typical passenger cars striking thedevice at relatively small angles of impact.

However, road safety barrier systems may have reduced performance if—

(i) struck by cars at larger angles of impact and higher speeds;

(ii) struck by heavier vehicles; or

(iii) impacted by pedal cyclists and motorcyclists.

Similarly, on low volume and low speed roads, a road safety barrier system that isless expensive than road safety barrier systems designed to cope with the higherloadings may be appropriate.

(b) Cost benefit/risk analysisA soundly constructed, cost benefit/risk analysis shouldbe conducted prior to the installation or replacement of road safety barrier systems.An appropriate cost benefit/risk analysis should address, but should not be limitedto, the following minimum impact return frequencies for which a road safety barriersystem is selected:

(i) 1 in 50 years if the consequences of an accident are limited to the errantvehicle only.

(ii) 1 in 100 years otherwise.

(c) Resolution of benefit/cost/risk analysisEarly resolution of the cost benefit/riskanalysis issues should be part of the specification process to ensure that the purposeof the installation is clearly understood. The ‘do nothing’ option of not installingany road safety barrier system at the site should always be considered. Preferredpractice would be to install relatively inexpensive road safety barrier systems atmore sites, instead of providing very expensive road safety barrier systems at fewsites, provided that the trade-off in performance is acceptable.

(d) Heavy or faster vehiclesWhere it is expected that the traffic mix will comprisehigh volumes of truck traffic or higher speeds, or both, or where the site ischaracterized by poor geometry, and a significant hazard exists should the roadsafety barrier system be penetrated by a larger vehicle, then road safety barriersystems designed to cope with the higher loadings may be appropriate.

(e) Pedal and motorcyclists The performance of road safety barrier systems whenimpacted by pedalcyclists and motorcyclists is rarely verified in testing. Specialmeasures may be necessary where the risk of impact by road users of this type isunacceptably high. At sites where a warrant for special measures for pedal andmotorcyclists has been established, modifications to remove gaps that would permita rider’s limbs to penetrate the road barrier system should be considered. The use ofroad safety barrier systems that present an unbroken wall should be given specialweighting when comparing options at such locations. If such treatment is notjustified, consideration should be given to—

(i) attenuation cushions on the exposed lower parts of posts and on wire ropes;

(ii) posts of a more user friendly nature; and

(iii) caps made of plastic or similar soft material on the top of posts.

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(f) Performance The road safety barrier system should be able to contain or redirectthe design vehicle impacting at the speed and angle of impact determined for thesite. At all points along the installation, the likely vertical trajectory of theimpacting vehicle is to be determined, so that impact height can be determined. Formost road safety barrier systems, this height will be critical.

Road furniture, such as kerbs in front of a road safety barrier system should beassessed to determine whether they might influence the vehicle trajectory in such away as to alter the likely impact height and place it outside the range of acceptablevalues for the road safety barrier system. Where appropriate, adjustments should bemade.

(g) Transverse location As a principle, a road safety barrier system should be locatedas far from the traffic lanes as possible, and this should not affect the height atwhich the design vehicle will impact the road safety barrier system. However, theincreased angles of impact at lower speeds, associated with greater offsets, shouldbe taken into account.

(h) Variation from recommended practiceWhere the intended use of a tested roadsafety barrier system varies from the manufacturer’s recommended practice, thespecifier should indicate how the variance will affect the road safety barrier’sintended performance.

B2.3.6 Plan details The link between horizontal radius and road safety barrierperformance can be difficult to establish. Manufacturers of road safety barrier systemshave to provide details which should include the following:

(a) The minimum curve radius that can be accommodated.

(b) The modifications necessary to their road safety barrier system to provide for smallradius curves.

(c) The operational differences that may arise for convex and concave installations.

These matters have special importance at intersections and on roads with alignments inmountainous areas.

The combination of small horizontal radius curves with crest or sag vertical curves shouldbe carefully reviewed.

B2.3.7 Elevation details Road safety barrier systems with relatively narrow widths ofsurface available for impact by a vehicle are vulnerable to vaulting or to vehicleunder-ride. Consequently, the height of such road safety barrier systems becomesimportant both in terms of mounting height and irregularities in the approach terrain,which may cause the impact height to be different than expected.

B2.3.8 Transverse details Preferred practice is for road safety barrier systems to beplumb if the cross-fall is less than 4.5%. For steeper cross-falls, preferred practice is forthe device to be perpendicular to the road surface for traffic which would travel up thecross-fall to hit the device, and vertical if traffic approaches the device down thecross-fall. At bridges and at sites where the road safety barrier system is to be erected ona structure, this practice may not be available and the details specified on the approachesshould then be integrated.

Regulations require that the body of a motor vehicle overhang its wheels. To minimizenuisance damage to both vehicle and the road safety barrier systems, it may be desirableto offset the face behind a road safety barrier kerb. A distance of 200-300 mm isgenerally required. This treatment can only be used where the speed limit is less than70 km/h. The increased risk to pedal and motorcylists should also be considered beforeimplementing such an offset.

A roadside safety barrier is considered to be flared when it is not parallel to the edge ofthe travelled way. A flare is normally used to either—

(a) locate a road safety barrier terminal further from the road way; or

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(b) change the off-set of the road safety barrier system from the travelled way (such aslocations where the width of shoulder changes at the approaches to a bridge).

For rigid road safety barrier systems, the flare rates should not exceed the values given inTable B1 for the relevant condition, unless testing shows that more severe rates areacceptable.

TABLE B1

FLARE RATES FOR RIGID ROAD SAFETY BARRIER SYSTEMS

85th percentile speed

(km/h)

Offside distanceto shy-line

(m)

Nearside distanceto shy-line

(m)

Road safetybarrier inside

shy-line

Road safetybarrier beyond

shy-line

≥100 3.0 2.0 30:1 20:1

90 2.5 1.5 25:1 15:1

80 2.0 1.0 20:1 15:1

70 1.5 1.0 15:1 10:1

≤60 1.5 1.0 15:1 10:1

For non-rigid road safety barrier systems, the flare rates should not exceed the valuesgiven in Table B2 for the relevant condition, unless testing shows that more severe ratesare acceptable.

TABLE B2

FLARE RATES FOR NON-RIGID ROAD SAFETY BARRIER SYSTEMS

85th percentile speed

(km/h)

Offside distanceto shy-line

(m)

Nearside distanceto shy-line

(m)

Road safetybarrier inside

shy-line

Road safetybarrier beyond

shy-line

≥100 3.0 2.0 30:1 15:1

90 2.5 1.5 25:1 10:1

80 2.0 1.0 20:1 10:1

70 1.5 1.0 15:1 10:1

≤60 1.5 1.0 15:1 10:1

The general principle should be that the flare rate adopted should not differentiatebetween permanent and temporary installations. However, the hazard associated with thelonger lengths of road safety barrier systems associated with a small flare rate can beeffectively balanced against the risk associated with a shorter period of exposure. Underthese circumstances, a flare rate as high as 5 to 1 may be adopted, provided it is for ashort-term installation (a few weeks) or where the traffic volumes are very small. A riskanalysis should be used to make this decision.

Where pedestrian facilities are incorporated behind a road safety barrier system, thedesirable minimum height of the road safety barrier system is to be approximately1200 mm above the surface of the footway. Where provision for pedal cyclists is required,the desirable minimum height above the surface of the bikeway should be approximately1400 mm. Separate rails may be provided to meet these requirements provided they do nothave the potential to spear through an impacting vehicle, create debris that poses a serioushazard, or change the characteristics of the road safety barrier system to the extent thatcrash outcomes are significantly altered.

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Road safety barrier systems can be basically classified as rigid or non-rigid. Provided thatsufficient width is available behind the road safety barrier system for the transversedynamic deflection, non-rigid road safety barrier systems are preferred due to the loweraccelerations experienced by the occupants of an impacting vehicle. Where space is notavailable to allow any dynamic deflection, then a rigid road safety barrier system is to beprovided. It is then likely that the accelerations experienced by vehicle occupants will behigher when impacting such road safety barrier systems. As this increases, the possibilityof injury to vehicle occupants, the necessary ‘trade offs’ need to be addressed. A check isto be made to ensure that the working width necessary is available.

For determining the approach conditions, particular care should be taken to ensure that animpacting vehicle will strike the road safety barrier system at an appropriate height.

The selected road safety barrier systems should indicate satisfactory performance eitherthrough crash testing or by careful assessment of the accident history of existing approvedroad safety barrier systems operating within the range of expected impact conditions.Referenced should also be made to Clause 2.3.13.

B2.3.9 Foundations on natural ground The conditions of the foundation at the sitewhere the road safety barrier system is to be installed are to be carefully assessed toensure that the expected level of support is available. Conditions, such as soft ground,rock, mounting on culverts, that may reduce the effectiveness of the installation should bedocumented and the appropriate adjustments or prohibitions should be detailed.

B2.3.10 Foundations on structures Where road safety barrier systems are to beerected on structures, the following are to be ensured:

(a) No damage occurs to the supporting structure due to the loading imposed during acrash.

(b) Rapid restoration of the road safety barrier system is available following a crash.

B2.3.11 End treatments Terminals of road safety barrier systems are known to haveparticular problems that should be addressed to achieve their required crash performance.Particular care should be taken with their selection and location.

Terminals may incorporate an anchor to the road safety barrier system, where this isnecessary, to develop the full tensile strength of the road safety barrier system duringimpacts away from the terminal.

The leading and trailing terminals of road safety barrier systems are not to cause animpacting vehicle to roll, vault or yaw in an inappropriate manner. The terminal is not tospear the vehicle or cause undue problems with debris. The terminal should performacceptably when impacted from either direction, except when erected on single directioncarriageways where there is a low probability of a vehicle coming in the reverse direction.The terminal should not aggravate injuries likely to be sustained by an unprotected roaduser.

Terminal treatments should not distinguish between a temporary or permanent situation.The only exception may be an allowance for the reduction of impact forces where the siteis effectively managed, i.e. if the maximum traffic speed is controlled, then a lowerperformance end treatment may be used than otherwise required.

A terminal is to be tested to NCHRP 350 before it is used on the road to warrant theabove functions. As tests are usually conducted in a controlled environment, the actualsite conditions should be considered when selecting an end treatment. Road safety barriersystems designed prior to this requirement being specified, which can be shown to haveperformed well during in-service evaluation, need not be retested unless their details havebeen modified.

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Terminals are subdivided into the following:

(a) Gating terminals Terminals that are designed to break away, pivot or hinge, and toallow a vehicle to pass through when impacted at an angle to the end or at a pointupstream of the beginning of the length of the associated road safety barrier system.

(b) Non-gating terminals Terminals that are designed to redirect a vehicle and absorbpart of the energy of an impacting vehicle at any point along the terminal withoutallowing it to pass behind the road safety barrier system.

The choice of gating or non-gating terminals is site and traffic specific, and depends upona number of factors, including—

(i) whether the terminal is located in a verge or median;

(ii) what the terminal is protecting; and

(iii) what hazards exist beyond the safe run-out area.

There are many proprietary and public domain systems available in the market. Theproprietary systems are to be installed, maintained and used as recommended by themanufacturer. Table B3 lists the up-to-date systems with the minimum installation and siterequirements.

TABLE B3

UP-TO-DATE SYSTEMS WITH MINIMUM INSTALLATIONAND SITE REQUIREMENTS

Systemname

Run-outrequired length × width

(m)

Maximum slopeadjacent to

installation site

Standard length(excluding transition)

(m)

ProprietarySystem

Slotted breakawaycable terminal

(SBCT)22.5 × 6 10:1 11.5 No

Modified eccentricloader terminal

(MELT)22.5 × 6 10:1 11.5 No

B2.3.12 Interfaces Where a road safety barrier installation is composed of differentsystems, e.g. with different characteristics, it is essential that the total installation act inharmony. This is of great importance where a horizontally weaker system is in advance ofa horizontally stronger system, such as locations where a rigid road safety barrier systemis used on a bridge and a non-rigid road safety barrier system is used on the approaches tothe bridge. Where different road safety barrier systems interface, and there is a markeddifference in the horizontal stiffness of the two systems, a transition is to be provided.Details of the appropriate connections, such as those to be used if the road safety barriersystem is required to operate in conjunction with a road safety barrier system that hasdifferent operational characteristics, should be provided. Detail of inappropriate practices,such as interfaces, should also be provided.

Road safety barrier systems that vary in height are considered as different road safetybarrier systems and should have an appropriate transition detailing.

B2.3.13 Attachments Attachments to a road safety barrier system can change itsmanner of operation in a crash. This is particularly the case where rails, and similarelements that could stiffen a non-rigid road safety barrier system are being considered.The risk that elements will become detached or act as spears is also to be assessed.

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Elements proposed to be located above the road safety barrier system could be struckduring crashes with high vehicles. This is particularly the case where non-rigid road safetybarrier systems are installed, where such systems generally have high working widths.Careful assessment to determine the appropriate crash outcomes is required.

B2.3.17 Opening in the surface Because of the methods of construction associatedwith passenger cars, it is likely that elements, such as the bonnet, can penetrate throughgaps left in the face of a road safety barrier system. This can cause unacceptable ridedown acceleration and yawing as the components of the vehicle hit vertical members. Itcan also cause the components to enter into the passenger cabin.

The provisions of Clause 2.3.17 do not apply if a road safety barrier system has beencrash tested. Where there is a high risk that the crash may involve a pedal cyclist or amotorcyclist, the road safety barrier installation should be reviewed to see whether asystem can be used which does not allow penetration by riders’ limbs. If this is notpossible, the openings should be restricted to 20 mm with a maximum of 100 mm.

B2.3.19 Impact conditions The vehicle and road safety barrier collision involves acomplex sequence of dynamic events. It is very difficult to derive the actual loads to beresisted. From the perspective of road safety barrier strength and vehicle containment, theprimary collision is believed to be the most important factor. If the vehicle can beredirected parallel to the road safety barrier system, it will be contained on the traffic sideof the road safety barrier system in almost every case. Accident data that showspenetration of a road safety barrier system during a second collision is not available.

The impact loading severity can be inferred by a quasi-energy equationE = 1/2 mv2sin θ2.Assigning a vectorial sense to energy, which is a scalar quantity, is technicallymeaningless. However, for uniformly loaded vehicles, it can be shown that there is arelationship between energy and maximum road safety barrier deflection during theprimary collision.

The redirection index estimates the horizontal impulse on a longitudinal road safetybarrier system during a vehicle collision from the incident of impact until the vehiclebecomes parallel with the road safety barrier system, or loses contact with the road safetybarrier system.

B2.4.1 General It is expected that—

(a) the road safety barrier system erected and the materials used are in accordance withthe specification;

(b) advice would be obtained about particular site problems that may arise. Issueswould include curved installations, sites where specified post depths are notpracticable, and site conditions that are different to those envisaged;

(c) documentation of the product is provided, adequate enough to ensure that theinstallation can be performed satisfactorily;

(d) installers follow the documentation provided for installing the road safety barrier inaccordance with the specification. The method of erection should not damage ormark the appearance of the road safety barrier system or other road components inthe vicinity of the installation or create unnecessary hazards for road users such assharp edges and protruding bolts;

(e) where the properties of critical components are expected to change over time, theappropriate procedures to allow determination of the remaining life of suchcomponents are to be specified;

(f) guarantees will be provided as to the availability of replacement components, oracceptable equivalents, within a reasonable time;

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(g) a process is to be used that will not damage or distort components, so that theycannot function in the manner intended or significantly reduce the span of life of theroad safety barrier system;

(h) a method of erection is to be adopted that does not damage or mark the appearanceof the road safety barrier system or other road components that are in the vicinity ofthe installation, or create unnecessary hazards for road users, such as sharp edgesand protruding bolts;

(i) foundation restoration is to be carried out in a manner that will not allow criticalareas, such as the areas of backfill around posts, to develop properties that aresignificantly less than the expected levels of support during wet conditions; and

(j) resources are available to obtain advice about particular site problems that mayarise. Issues would include curved installations, sites where specified post depthsare not practicable and where site conditions are different to those envisaged.

B2.4.2 Damage and B2.4.3 Component identification and assembly detailsIncorrect assembly of a road safety barrier system can introduce profound changes into itsmanner of operation. Incorrect assembly can be caused through damage to criticalcomponents which do not allow the correct assembly to occur. Confusion regarding thecorrect orientation of elements, or even substitution of elements into incorrect positionscan cause problems. It is expected that road safety barrier systems are assembled by thosefamiliar with the process. It is also a requirement that such people are aware of themethods of coping with the variations that can occur in site conditions. However, detailsof the appropriate assembly process should be provided by manufacturers. Texts thatprovide a check-list to ensure that critical elements are properly assembled are alsorequired.

B2.4.4 General tolerances The particular perspective that motorists have of a roadsafety barrier system makes a smooth, even alignment an important necessity to beachieved.

B2.4.5 Surface finish A smooth surface of the road safety barrier system reduces thepossibility of a vehicle yawing on impact. It also promotes a vehicle sliding along theroad safety barrier system, which ensures that ride down accelerations are kept as low asis practical. A smooth surface also reduces the risk of fire.

The surface finish should hard so that it does not show incidental damage. Surfacetreatments may be coloured but these should not accentuate any problems of incidentaldamage.

Great care should be taken with the design, to ensure that any protrusions are minimized.The desirable design would be free of any elements that could snare or penetrate.Protrusions on top of the road safety barrier system, or behind the road safety barriersystem, that are likely to snag people are to be avoided.

B2.4.6 Setting out The proposed installation should be carefully assessed to ensurethat its location is optimal. The area behind any road safety barrier system that ‘gates’ isto be carefully reviewed.

B2.4.7 Sequence of work Where possible, a road safety barrier system is to be erectedso that the leading terminal is completed at the earliest possible moment and the rest ofthe road safety barrier system is erected in the direction of traffic.

Special provisions to reduce the hazard of construction on roads open to traffic should bespecified.

B2.4.8 Installation acceptance criteria for posts Driving posts is an acceptablepractice, provided that it does not cause distortion or damage to the posts such that itreduces either the effectiveness of the road safety barrier system, or its span of life. Siterepairs are acceptable, provided they are in accordance with the specifications.

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It is important that posts are inserted to the full design depth. Where it is considered thatthis is practically impossible, the matter is to be documented. Cutting the ends off postsmay be permissible to one or two adjoining posts, provided that the integrity of the roadsafety barrier system is not reduced by such a practice.

B2.4.9 Construction acceptance criteria for foundations The foundations of the roadsafety barrier system are a critical element which ensures that the road safety barriersystem performs as tested. It is expected that manufacturers, designers and erectors reviewthe foundation conditions to ensure that the intended outcomes will be achieved in case ofa crash.

For non-rigid road safety barrier systems, the provisions of additional anchors may beused at sites where the necessary levels of support are not available. Using rails of heavierthickness, either a thicker gauge or ‘nesting’ of elements can be used. Details ofappropriate crash-tested solutions are available.

For non-rigid road safety barrier systems in the public domain using posts, the followingconditions should be met:

(a) The steel posts should be able to move, i.e. they should not be surrounded byconcrete or similar material that restricts flexibility.

(b) Failure mode of the steel post is to be plastic yielding at a depth not less than75 mm below ground level.

(c) The foundation area should be sufficiently strong to allow the appropriate failuremode of the post to occur. In this regard, due attention is to be paid to the extent ofthe ground support available at each post and an assessment made about any likelychange in the amount of local ground support that may occur during wet weather.

B2.4.10 Construction acceptance criteria for concrete The criteria given inClause 2.4.10 are those normally associated with high quality structural concrete.

B2.4.11 Plastic Plastic road safety barrier systems can be made of materials that cancatch fire. In a crash, there is a risk that the vehicle will catch fire. Accordingly, thematerials of the road safety barrier system are not to act as a fire accelerant to thesituation.

The opportunities for vandals to damage the road safety barrier system is also to beaddressed. Any surface coating on the road safety barrier system should not be capable ofbeing easily ignited nor capable of being easily damaged by sharp objects.

Details of the acceptable sites for the installation of plastic road safety barrier systems areessential given the various applications that occur.

Attention is to be paid to the speed zone to ensure that the road safety barrier system willnot be impacted by vehicles travelling at speeds that are outside the test level regime.

Due to the type of material used in plastic road safety barrier systems and the wide rangeof applications and periods of use on site, plastic road safety barrier systems requirefrequent inspection.

The documentation supplied by the manufacturer should include the methods for thedisposal of discarded plastic road safety barrier sections.

B2.4.12 Construction acceptance criteria for steel componentsDesign elements areto be correctly assembled. Particular care is to be taken with the overlap or orientation, orboth, of components, tension in bolts and the damage to any metal protection system,unless specified otherwise. Damage to protection systems should be restricted in the totalarea that is allowed to be repaired. Particular care is to be taken with stacking ofcomponents so that break down of the protection system does not occur.

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B2.4.13 Acceptance criteria During the process of acceptance of the road safetysystem, care should be taken to ensure that the needs of particular road user groups havebeen properly assessed. Particular attention should be given to the following:

(a) Whether pedestrian rails should be provided at the back of steel posts.

(b) Protruding elements are either removed or rounded.

(c) The orientation of laps is appropriate.

NOTE: For further information, see Paragraph B2.5 of Appendix B.

B2.5 MAINTENANCE AND DISMANTLING It is expected that—

(a) clear guidance is provided about the surveillance procedures necessary to monitorthe road safety barrier systems;

(b) road safety barrier systems are regularly inspected in accordance with a program ofsurveillance;

(c) critical elements can be readily accessed and replacement of elements that havereached the end of their span of life is to be available; and

(d) feedback about issues relating to service performance, which may prove critical atsimilar installation, should be provided.

A program should be established for the inspection of non-rigid road safety barrier systeminstallation. The program should encompass the following:

(i) Stage 1 ‘Drive-by’ inspection to identify the need for repairs after impact andwhether sufficient ballast is present in the case of ballasted road safety barriersystems.

(ii) Stage 2 ‘Walk-by-and-stop’ inspection to identify the need for repairs due tovandalism, weathering, scour, changes to the adjoining ground and pavementsurface, addition or removal of kerbs, loss or looseness of fasteners or other parts,protruding or broken wires, slack in tension members, settlement of footings, loss ofdelineating devices, unauthorized changes made to the road safety barrier layout,changes to any poles, roadside vegetation and whether sufficient ballast is present inthe case of ballasted road safety barrier systems.

(iii) Stage 3 The criteria of Stage 2 applies to Stage 3, however, any specific technicalrequirement regarding that type of road safety barrier system are to be taken intoconsideration.

(iv) Stage 4 Full-scale inspection following the processes specified in Clause 4.2,together with a review of the performance of the non-rigid road safety barriersystem at that location, and considering the specific technical requirementsregarding that type of road safety barrier system.

(v) Stage 5 Detailed examination of the results of the inspections undertaken acrossthe non-rigid road safety barrier installation. Stage 5 should determine whether thereis a need to alter any of the procedures associated with the non-rigid road safetybarrier systems, including those for inspecting the non-rigid road safety barriersystems.

Procedures should be established for each stage of inspection, and should involve thefollowing:

(A) Pre-site inspection preparation, including the review of the findings of previousinspections at that site, recommendations made as a result of those inspections, andany other measures undertaken at that installation since the last inspection.

(B) Site inspection, including the actual inspection, digital and graphical recording offindings, comparison with the results and recommendations of previous inspections,preliminary evaluation of the scope, type and priority of remedial measures,preliminary evaluation of the need for a higher stage inspection.

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(C) Specification of flow-on action, resulting from reflection on the site inspectionfindings, together with any further investigation.

(D) Documentation of findings and recommendations for flow-on action.

B2.6 POST CRASH ASSESSMENT AND REPAIR It is expected that the actionplans as specified in Clause 2.6.1 should be implemented and that records be kept asevidence of that implementation. This plan will include procedures to identify and restorecomponents damaged in crashes, natural events or by vandalism. It is not expected thatrepairs will be undertaken immediately; however, the site should not remain in ahazardous or unsafe condition. Even extraordinary repairs may be deferred depending onthe site, resources and other matters.

The following are to be determined after a crash:

(a) Did the device function in the manner intended.

(b) Would it be appropriate to repair the device and place it back in service.

(c) Should the whole device be replaced with the same type of road safety barriersystem.

(d) Should the type of road safety barrier system be changed.

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APPENDIX C


(Informative)

C3.1 SCOPE All road safety barrier systems can be viewed as rigid during low energyimpacts. However, Section 3 specifies those road safety barrier systems that are designedso that there is no dynamic deflection during an impact by the design vehicle travelling atthe test level speed and angle of impact.

C3.2 GENERAL Rigid road safety barrier systems are often used along the edge ofroad structures, such as bridges, retaining walls and the like. However, the installation ofa rigid road safety barrier system is no guarantee that containment of an impacting vehiclewill occur.

Under the test conditions specified in this Standard, a rigid road safety barrier system isrequired to meet specified outcomes. Included in these outcomes are requirementsregarding the accelerations and velocity of impact experienced by vehicle occupantsduring a crash. Non-rigid road safety barrier systems generally have better outcomes thanrigid road safety barrier systems. However, a rigid road safety barrier system may be theonly option at some locations. These include sites where there are features behind the roadsafety barrier systems, such as a pedestrian footpath and public utility duct, which dictatethat the road safety barrier should not be permitted to move.

Properly designed rigid road safety barrier systems give better results when impacted atlower angles than the test values. This is generally achieved by placing the road safetybarrier system in close proximity to traffic lanes. However, on multi-lane bridges, it ispossible that even this measure will not reduce the impact angles in some crashes. Placingroad safety barrier systems a long distance from the carriageway, increases the impactangles, but reduces impact speed.

C3.3 DEVELOPMENT OF DESIGN For all road safety barrier systems, the need toconsider the outcomes when the road safety barrier is impacted by vehicles that havehigher levels of kinetic energy is necessary. Particular attention should be paid to thelocation of the centre of gravity as some of these higher kinetic energy situations willinvolve vehicles of larger mass and higher centres of gravity. The issue of working widthshould be considered at sites where rigid road safety barrier systems could be impacted byhigh vehicles. Crash tests show that such vehicles can roll over the top of the road safetybarrier system unless it is high enough to restrain such movement. This means that tallelements behind a rigid road safety barrier system may be impacted by the upper parts ofsuch vehicles.

The need for a compromise between limiting horizontal deflection whilst controlling thein-vehicle accelerations during the process of absorbing the energy of the impactingvehicle is a trade off that should be made consciously. Rigid road safety barrier systemscan have higher ride down accelerations. Accordingly, the risk for personal injury tooccupants in the vehicle will be increased with such devices.

In the development of the design, the hazard associated with portions of a vehicle loadcoming off during an impact should be considered. As well, the loss of vehiclecomponents, such as vehicle hubcaps, may pose an unacceptable risk at some sites.

C3.4 ANALYSIS OF STRESSES IN RIGID BARRIERS Longitudinal road safetybarrier systems should be designed and constructed to restrain the idealized designvehicle, e.g. car, truck or bus, from penetrating the road safety barrier system.

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Horizontal and longitudinal loads are to be distributed as shown in Figure C1. Theintensity of longitudinal load should be calculated as a product of the coefficient offriction (µ) and the horizontal load. The coefficient of friction (µ) should not be less than0.4 for concrete type F barrier. It may vary for other shapes.

The value of the longitudinal length of the distributed impact force (l t) should be as givenin Table C1 for the appropriate type of vehicle, unless a crash test of a vehicle provesotherwise.

Sufficient reinforcement should be provided to a concrete road safety barrier system tohave the required flexural capacity along the v-shaped yield line. The critical length of theyield line failure pattern (lc) should be determined as follows:

(a) For impacts at the end of the road safety barrier system or at the joint, from thefollowing equation:

. . . C1(1)

(b) For impacts within the road safety barrier segment, from the following equation:

. . . C1(2)

where

Mb = additional flexural resistance of the beam in addition toMw

Mc = flexural resistance of the foundation or the cantilever

Mw = flexural resistance of the barrier wall

The total resistance of road safety barrier system (R) should be determined as follows:

(i) For impacts at the end of the road safety barrier system or at the joint, from thefollowing equation:

. . . C1(3)RMb

l c −l t

2

Mw hi

l c −l t

2

Mc l 2c

hi(l c −l t

2)

(ii) For impacts within the road safety barrier segment, from the following equation:

. . . C1(4)R8Mb

l c −l t

2

8Mw hi

l c −l t

2

Mc l 2c

hi(l c −l t

2)

Road safety barrier systems that rely on continuous support from the foundation generatesome efficiencies due to the length available to dissipate the impact stresses. Post systemstend to concentrate the loading. Details of the connection between the road safety barriersystem and the structure should be designed with a ‘fuse’ arrangement that facilitatesrepair and ensures that stresses in the supporting structure are not exceeded. Where thissupporting structure is a bridge, it should be noted that there are practical limits in thecapacity of the structure to cope with the loadings from a road safety barrier system.Table C2 provides a guide about the suggested maximum design loads for the appropriatetest level.

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The stiffness of the bodies of trucks means that the crash outcomes with such vehicles islikely to be substantially different to that of passenger cars. The impact from a rigidsingle unit vehicle is often more severe than the impact from an articulated vehicle of thesame mass. The longer impact periods associated with an articulated vehicle are of realbenefit.

Designers should note that there are some practical difficulties associated with containingvehicles having a high centre of gravity. Above a height of approximately 1200 mm fromthe ground, there is a marked reduction in the stiffness of the bodies of such vehicles.Accordingly, it may be difficult to provide effective methods of providing transverserestraints at levels above 1200 mm. Even road safety barrier systems with a solid facemay cause considerable structural damage to vehicles at heights above the tray.

TABLE C1

LONGITUDINAL LENGTH ( l t)

Type of vehicleLongitudinal length ( l t)

(mm)

Pick up or small vehicle 1 200

Van or truck with single rear axle 1 070

Truck with rear tandem axles 2 400

TABLE C2

SUGGESTED MAXIMUM DESIGN LOADS

CategoryDesign load

(kN)

Minimum heightabove road surface

(mm)

Test level 2 100 535



Test level 5 < 700 1 500

NOTE: For test level 3 the minimum height for W-beamrail shall be 535 mm measured to the centre of the rail.

C3.7 FOUNDATIONS The loading that is to be absorbed by the support structureshould also be considered with the design of a rigid road safety barrier system. It isimportant to ensure that the support structure remains intact during the design impact. Anassessment is also to be made about the consequence to the support structure when theactual impact loading is higher than the design levels.

It should also be noted that there is a wide range of energies that could be used in thedesign of a rigid road safety barrier system. It is not possible to design for the worst case.

C3.12 RIGID ROAD SAFETY BARRIER SYSTEMS IN THE PUBLIC DOMAINWhere the speed limit on the road is 80 km/h or higher, preferred practice is to locatepedestrian and pedal cycle facilities on the outside of any road safety barrier system.Figure C2 shows the preferred arrangement.

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where

lc =critical length of the yield line pattern, in millimetres

lt =longitudinal length of the distributed impact force, in millimetres

hi =height of the impact force above road surface, in millimetres

FIGURE C1 STRESSES IN RIGID ROAD SAFETY BARRIER SYSTEM

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FIGURE C2 ARRANGEMENT OF FOOTWAY AND PEDAL CYCLE FACILITIES

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APPENDIX D


(Informative)

D4.1 SCOPE Unprotected road users to be taken into consideration includemotorcyclists, pedal cyclists and pedestrians.

At many sites the following possible events should be considered:

(a) Glancing impacts which may cause significant damage to the road safety barriersystem.

(b) The impacting vehicle or unprotected road user may snag on the road safety barriersystem.

(c) The non-rigid road safety barrier may deflect so far as to cause the impactingvehicle to hit an object or facility located in the roadside or abutting property. Theconsequences of such an impact may then be for a bridge pier to collapse.

(d) The impacting vehicle may penetrate or vault the road safety barrier system. Theconsequences may be that the vehicle penetrates into abutting property and causesinjury to the occupants of that property, for example, children in kindergartenplaygrounds.

(e) On narrow medians, a non-rigid road safety barrier may deflect on impact to theextent that oncoming traffic is caused to swerve or brake suddenly, which may leadto a secondary accident.

At some sites, traffic volumes may be so large or the road geometry may be so confined,or both, that repairing the road safety barrier would cause serious traffic congestion. Suchcongestion could create the risk of additional traffic accidents and place staff repairing theroad safety barrier system at risk. At such sites, special attention would need to be givento the ease and speed of repairs to the non-rigid road safety barrier system. Alternatively,it may be desirable to use a rigid road safety barrier system which rarely requires repairafter impact.

D4.3 INSTALLATION Clause 4.2 specifies that the features of each site willinfluence markedly what type of non-rigid road safety barrier system should be used atthat site and what should be the road safety barrier layout. This means that if the sitefeatures change, then the type of road safety barrier system or its layout, or both, may nolonger be appropriate.

D4.4 DEVELOPMENT OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS

D4.4.1 General The requirements specified in Clause 4.4.2 arise because of the needto minimize the potential for unprotected people to be struck by failing wire ropes. Up tonow the longitudinal components of metal non-rigid road safety barrier systems have beeneither beams or wire ropes. Thus there seems not to have been any road safety barriersystems whose longitudinal components areboth beams and tensioned wire ropes.However, some non-rigid road safety barrier systems under development will comprisebeams and heavily tensioned wire ropes in one and the same road safety barrier.

It has, therefore, been necessary to cease referring to ‘wire rope road safety barriers’ andinstead to ‘road safety barriers embodying tensioned wire ropes’.

The steel cable in the breakaway cable terminal is under very little tension, so there is nopossibility that the steel cable could fail and injure an unprotected person. Accordingly,the breakaway cable terminal and its successors are not considered as ‘road safety barriersembodying tensioned wire ropes’.

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D4.4.2.1 Intended function Already there are a few road safety barrier systems thatperform as rigid road safety barriers when hit by cars, but perform as non-rigid roadsafety barriers when hit by heavy commercial vehicles. In the future it is possible thatroad safety barrier systems will be developed with several redirective stages. With theseroad safety barrier systems, the Stage 1 behaviour will mean that the road safety barriersystems perform as non-rigid road safety barrier systems when hit by cars and the Stage 2behaviour will mean that the same road safety barrier system behaves as a non-rigid roadsafety barrier system when hit by heavy commercial vehicles.

D4.4.2.2 Practical usefulness It is acknowledged that it may be practically impossiblefor developers of non-rigid road safety barrier systems to design systems to cater for thefull range of situations likely to be encountered on site. However, it is important thatdevelopers recognize that to be operational, road safety barrier systems should be sitefriendly. Figure D1 shows some situations into which the road safety barrier systems areoften required to fit.

Clauses 4.2 and 4.3 specify that specialized information is required for making decisionsregarding non-rigid road safety barrier installations. It is recognized that until a roadsafety barrier system has been in service for some time, some of this specializedinformation may be unavailable.

D4.4.3.2 Rope tension, anchorage and tension devicesThe design of anchorages andtension devices, their spacing along the length of the road safety barrier system and theprocedures associated with the road safety barrier system should be such as to—

(a) enable the required tension to be developed in all of the ropes along the full lengthof the road safety barrier system with special consideration being given to thefollowing:

(i) Any curvature of the road safety barrier system in the horizontal plane.

(ii) The vertical alignment of the road safety barrier system.

(iii) Any tension losses along the length of the road safety barrier system. It ispossible, for example, that where a wire rope changes direction at a post, thefriction between the rope and the post may be so large as to cause a tensiondrop at that point. This in turn can mean that along the length of the ropethese tension drops can form a ‘tension profile’ and that the tension ‘loss’becomes so large as to impair the effective performance of the road safetybarrier system.

(iv) The likely temperature range of the ropes in service.

(b) prevent sudden release of tension in a rope if one particular tension device isreleased whilst leaving the other tensioning devices fully tensioned. If the tension ina wire rope is suddenly released, the rope may fly sideways very violently so as toinjure or kill a pedal cyclist, a motorcyclist or an unprotected person nearby. Itcould be argued that the authorities responsible for working with the road safetybarrier systems would be aware of the risks involved with this type of road safetybarrier system. However, in an emergency or through vandalism, a lay-person couldundo a rope tensioning device and this action could have tragic consequences if thisde-tensioning causes the sudden release of the tension; and

(c) ensure that all of the components of the road safety barrier system remain in theircorrect location relative to each other. Normally, this will involve examining andplanning the behaviour of the road safety barrier system under the followingconditions:

(i) When the road safety barrier system is at rest.

(ii) Under any unexpected temperature or climatic conditions.

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(iii) During vehicular impact.

NOTE: This is to ensure, for example, that if a road safety barrier system is used on a sagcurve, then the wire ropes do not pull free of the posts when the road safety barrier is atrest.

(d) avoid any potential for entrapment of limbs by tensioning devices along the lengthof need.

D4.4.3.3 Rope diameter The requirement of 19 mm min. diameter is to prevent the useof smaller diameters which might increase the risk of injury to an unprotected road userwho hits the ropes. Also, the 19 mm minimum diameter ensures that the ropes have atensile strength sufficient to prevent fracture of the ropes during impact.

D4.5.1 General The types of public domain road safety barrier systems given inTable 4.5.1 are the only ones that are permitted. This is because at the time of preparingthis Standard, they are the only public domain road safety barrier systems for which thereare public domain crash-safe terminals and structure transitions.

D4.5.2 Area between traffic lane and road safety barrier system Vehicles mayoverturn following impact with the non-rigid road safety barrier system if the groundbetween the traffic lane and the road safety barrier system is uneven or contains adepression such as a v-shaped drainage channel.

Vehicles may vault the non-rigid road safety barrier if—

(a) there is a barrier kerb or semi-mountable kerb between the traffic lane and the roadsafety barrier system;

(b) the area between the traffic lane and the road safety barrier system has a cross-fallgreater than 1 on 10; or

(c) both.

D4.5.3 Location and orientation of steel blockouts, posts and nailing lapsThis willinvolve examining the potential roadside encroachment frequencies of adjacent trafficlanes.

D4.5.4 Post foundations on natural ground The satisfactory performance of thesenon-rigid road safety barrier systems requires that if the road safety barrier system is hitby the range of vehicles, the posts remain in place to develop a substantial part of theirbending strength and the soil behind the posts then yields enabling the posts to yieldapproximately 75 mm below the ground.

If the soil surrounding the posts is too weak, the posts will plough through the ground toosoon, so that the road safety barrier system may deflect too far and perhaps cause theimpacting vehicle to vault the road safety barrier system.

Post footings are generally satisfactory if—

(a) there is a level area of consolidated material, not soft sand, at least 1 m wide behindthe road safety barrier posts;

(b) the posts are not mounted rigidly on concrete footings such as slab, beams orconcrete piles;

(c) the posts are not encased rigidly in concrete blocks; and

(d) the posts are not driven into cement-stabilized pavements, nor into deep-liftasphaltic concrete.

When backfilling around posts, it should be remembered that failure to rod the materialcan cause an arch or void to form, which cannot be removed by normal tamping methods.If it is suspected that arching or voiding has occurred, the situation can sometimes berectified by water-jetting the backfill around the posts. However, if water-jetting isperformed, care should be taken to ensure that the water-jetting does not damage theparent material surrounding the hole.

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In some locations, the material close to the ground surface is not so hard as to support theposts too rigidly, yet below the ground there is very stiff clay or small boulders such thatwhen the posts are driven into the ground, the head of the post is damaged by the drivinghammer. Sometimes, such damage can be prevented by using a heavier hammer or using adriving helmet, or both, which fits the post more tightly.

D4.5.5 Anchorage of the W-beam or thrie-beam Failure to anchor the non-rigidpublic domain road safety barrier systems can cause the W-beams or thrie-beams todeflect too far between the posts, which can in turn cause the impacting vehicle to snagon the posts.

D4.5.6 Fixing of the W-beam or thrie-beam to the blockouts It is important thatwashers be installed only where shown in the figures of Appendix F. This is because in animpact, the W-beam or thrie beam should be able to pull free of the posts and therebyremain at the correct height. If the W-beam or thrie-beam does not pull free and instead isdragged down with the posts, the impacting vehicle will tend to vault the road safetybarrier system or snag on the posts.

FIGURE D1 (in part) SITUATIONS INTO WHICH NON-RIGID ROAD SAFETYBARRIERS MAY HAVE TO FIT

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FIGURE D1 (in part) SITUATIONS INTO WHICH NON-RIGID ROAD SAFETYBARRIERS MAY HAVE TO FIT

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APPENDIX E


(Informative)

For commentary on Section 5, see NCHRP Report 350.

A 1600 kg vehicle has been added to the test vehicles (see Clause 5.3) to provide analternative vehicle that represents a common larger passenger car. In most cases, a roadsafety barrier system will not be tested with the 1600 kg vehicle. Some road safety barriersystems may be evaluated at test level 0 and with the 1600 kg vehicle. The maximumimpact severity of test level 0 is 80% that of the value for test level 1.

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APPENDIX F

DETAILS OF A ROAD SAFETY BARRIER LAYOUT

(Normative)

This Appendix provides the following details of a road safety barrier system deemed tocomply with NCHRP 350, test level 3:

(a) Layout.

(b) Arrangements of transitions and terminals.

(c) Component details and specifications.

NOTE: The configuration in this Figure is of a typical road safety barrier layout regardless of the type of theroad safety barrier system.

FIGURE F1 DETAILS OF ROAD SAFETY BARRIER LAYOUT

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NOTE: Rail lap, post and blockout orientation in relation to traffic direction as specified in Clause 4.5.3 and shown in Figure F1.


FIGURE F2 AASHTO G4 W-BEAM ASSEMBLY

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NOTE: Rail lap, post and blockout orientation in relation to traffic direction as specified in Clause 4.5.3 and shown in Figure F1.


FIGURE F3 THRIE-BEAM ASSEMBLY—STANDARDS BLOCKOUTS

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NOTES:

1 Rail lap, post and blockout orientation in relation to traffic direction as specified in Clause 4.5.3 and shown in Figure F1.

2 Dimension from ground line to top of blockout is 865 mm as against 805 mm for standard blockout.


FIGURE F4 MODIFIED THRIE-BEAM ASSEMBLY—NOTCHED BLOCKOUTS

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FIGURE F5 INTERFACE DETAILS OF TYPE F TO W-BEAM(MEETS TEST LEVEL 3)

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FIGURE F6 INTERFACE DETAILS OF TYPE F TO THRIE-BEAM(MEETS TEST LEVEL 3)

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FIGURE F7 (in part) LEADING SLOTTED BREAKAWAY CABLE TERMINAL(MEETS TEST LEVEL 3)

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FIGURE F7 (in part) LEADING SLOTTED BREAKAWAY CABLE TERMINAL(MEETS TEST LEVEL 3)

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FIGURE F8 (in part) TRAILING SLOTTED BREAKAWAY CABLE TERMINAL(MEETS TEST LEVEL 3)

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FIGURE F8 (in part) TRAILING SLOTTED BREAKAWAY CABLE TERMINAL(MEETS TEST LEVEL 3)

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FIGURE F9 (in part) GUARD FENCE—BRIDGE APPROACHES (LONG END POST)(MEETS TEST LEVEL 3)

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FIGURE F9 (in part) GUARD FENCE—BRIDGE APPROACHES (LONG END POST)(MEETS TEST LEVEL 3)

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NOTE: Trailing terminals are to be used on departure end of road safety barrier only. They are not to be used within clear zone of opposing traffic.


FIGURE F10 GENERAL ARRANGEMENT TRAILING TERMINAL

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FIGURE F11 GENERAL ARRANGEMENT MODIFIED ECCENTRIC LOADER TERMINAL (MELT)

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FIGURE F12 W-BEAM

SPECIFICATIONS Corrugated W-beam elements shall be formed from steel gradeHA350 or equivalent in accordance with AS/NZS 1594.

Beam elements shall be stamped with the grade and thickness of the steel,i.e. 350-2.7 BMT.

The beam shall be treated and hot dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.

Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-richpaints shall be in accordance with AS/NZS 3750.9.

Dimensional tolerances not shown or implied shall be consistent with the properfunctioning of this part, involving its appearance and accepted manufacturing practices.

INTENDED USE This corrugated W-beam shall be used as a rail element in standardbarrier designs G4, MB4, MELT and trailing terminals.

The corrugated stiffener plate shall be placed behind rail elements at intermediate posts(non-splice posts) in standard barrier designs G4 and MB4.

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FIGURE F13 W-BEAM END RAILS

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SPECIFICATIONS W-beam end rails shall be formed from steel grade HA350 orequivalent in accordance with AS/NZS 1594.

Beam elements shall be stamped with the grade and thickness of the steel,i.e. 350-2.7 BMT.

The beam shall be treated and hot dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2,total both sides.



INTENDED USE These corrugated steel beams shall be used as rail elements in thestandard MELT and trailing terminals. See Figures F7 and F8.

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FIGURE F14 THRIE BEAM

SPECIFICATIONS Corrugated thrie-beam elements shall be formed from steel gradeHA350 or equivalent in accordance with AS/NZS 1594.Thrie-beams shall be stamped with the grade and thickness of the steel, i.e. 350-2.7 BMT.Thrie-beams shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-richpaints shall be in accordance with AS/NZS 3750.9.Dimensional tolerances not shown or implied shall be consistent with the properfunctioning of this part, involving its appearance and accepted manufacturing practices.

INTENDED USE Corrugated thrie-beams shall be used as a rail element in standardbarrier designs G9, G9 modified, MB9 modified and structure transitions.Corrugated stiffener plates shall be placed behind rail elements at intermediate posts(non-splice posts) in standard barrier designs G9, G9 modified and MB9 modified.

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FIGURE F15 W-THRIE TRANSITION SECTION

SPECIFICATIONS W-thrie transition section elements shall be formed from steelgrade HA350 or equivalent in accordance with AS/NZS 1594.

Beams shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE W-thrie transition sections shall be used as the transition sectionbetween the W-beam and thrie-beam barrier types.

NOTE: For further information, see Figure F5.

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FIGURE F16 C-POST — W-BEAM, TRANSITION BEAM

SPECIFICATIONS W-beam posts shall be formed from steel grade HA300 inaccordance with AS/NZS 1594.

Posts shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE W-beam posts shall be used with W-beam and transition beams instandard barrier types G4, MB4, trailing terminals and structure transitions.

For details of end post in the trailing terminals, see Figure F11.

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FIGURE F17 C-POST — THRIE-BEAM

SPECIFICATIONS Thrie-beam posts shall be formed from steel grade HA300 inaccordance with AS/NZS 1594.




INTENDED USE Thrie-beam posts shall be used with thrie-beams in standard barriertypes G9, G9 modified, MB9 modified and structure transitions.

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FIGURE F18 C-POST — END POST

SPECIFICATIONS End posts shall be formed from steel grade HA300 in accordancewith AS/NZS 1594.




INTENDED USE End posts shall be used in the standard trailing terminal.

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FIGURE F19 TIMBER POST

SPECIFICATIONS Timber posts shall be formed from grade F8 Queensland slash pine,preservative treated to hazard level H4/H5 in accordance with AS 1604.


INTENDED USE Timber posts shall be used in the standard MELT terminal.

NOTE: Short posts are installed with a rectangular steel tube and soil plate (see Figure F22 fordetails).

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FIGURE F20 TIMBER POST FOR NEW ZEALAND ONLY

SPECIFICATIONS Timber posts shall be produced from run of the mill pinus radiatapreservative treated to hazard level H4 in accordance with AS 1604.


INTENDED USE Timber posts shall be used in the standard guardrail panels.

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FIGURE F21 BLOCKOUT — W-BEAM

SPECIFICATIONS W-beam blockout blocks shall be formed from steel grade HU300in accordance with AS/NZS 1594.

Blocks shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE W-beam blockout blocks shall be used in standard barrier designs G4and MB4.

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FIGURE F22 BLOCKOUT — THRIE-BEAM

SPECIFICATIONS Thrie-beam blockout blocks shall be formed from steel gradeHU300 in accordance with AS/NZS 1594.

Blocks shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE Thrie-beam blockout blocks shall be used in standard barrier designsG9 and structure transitions.

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FIGURE F23 MODIFIED BLOCK — THRIE-BEAM

SPECIFICATIONS Modified thrie-beam blocks shall be formed from steel gradeHU300 in accordance with AS/NZS 1594.

Blocks shall be treated and hot dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE Modified thrie-beam blocks shall used in the standard barrier designsG9 modified and MB9 modified.

NOTE: Verge or median blocks are to be specified at time of ordering.

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FIGURE F24 BLOCK OUT — TRANSITION

SPECIFICATIONS Block-out transition blocks shall be formed from steel gradeHU300 in accordance with AS/NZS 1594.

Blocks shall be treated and hot dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE Block-out transition blocks shall be used in the standard structuretransition design shown in Figure F2.

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FIGURE F25 (in part) BUFFERED END SECTION AND DIAPHRAGM

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FIGURE F25 (in part) BUFFERED END SECTION AND DIAPHRAGM

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SPECIFICATIONS Buffered terminal sections and diaphragms shall be formed fromsteel grade HA350 or equivalent in accordance with AS/NZS 1594.

Sections and diaphragms shall be treated and hot-dip galvanized after fabrication inaccordance with AS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE Terminal sections shall be used in the standard MELT and trailingterminal designs as shown in Figures F3 and F4.

NOTE: Diaphragms are not required in a trailing terminal.

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FIGURE F26 STRUCTURE CONNECTOR — W-BEAM

SPECIFICATIONS Corrugated W-beam structure connectors shall be formed from steelgrade HA350 or equivalent in accordance with AS 1595.

Connectors shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE W-beam structure connectors shall be used in some of the railelement terminal configurations employed with the standard W-beam barrier type G4 andMB4 designs.

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FIGURE F27 STRUCTURE CONNECTOR — THRIE-BEAM

SPECIFICATIONS Corrugated thrie-beam structure connectors shall be formed fromsteel grade HA350 or equivalent in accordance with AS/NZS 1594.

Connectors shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.



INTENDED USE Thrie-beam structure connectors shall be used in some of the railelement terminal configurations employed with the standard thrie-beam barrier types G9,G9 modified and MB9 modified, and structure transitions as shown in Figure F2.

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NOTES:

1 Steel plate shall be grade 250 in accordance with AS/NZS 3678.

2 Reinforcing bar shall be grade 250 in accordance with AS 1302.

3 Weld category shall be in accordance with AS/NZS 1554.1.

4 Welding symbols shall be in accordance with AS 1101.3.

5 Ferrules only shall be hot-dip galvanized.

6 After assembly, galvanized surfaces shall be renovated with two pack organic zinc-rich primer.


FIGURE F28 CAST-IN ANCHOR ASSEMBLY FOR THRIE-BEAM

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FIGURE F29 ANCHOR BRACKET

SPECIFICATIONS Anchor brackets shall be formed from steel grade HA250 inaccordance with AS/NZS 1594.

Anchor brackets shall be treated and hot-dip galvanized after fabrication in accordancewith AS 1650.



INTENDED USE Anchor brackets shall be used to anchor the cable assembly (seeFigure F25) to the end rail in the standard MELT and trailing terminal design as shown inFigure F3.

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NOTES:

1 Dimensions are subject to manufacturer’s tolerances except where permissible tolerances arenominated.

2 All timber posts shall be grade F8 Australian slash pine preservative treated to hazard level H4 (H5 inextreme wet conditions) in accordance with AS 1604.

3 Timber posts shall be milled square. All longitudinal edges shall be chamfered 5 × 5.


FIGURE F30 STEEL TUBE AND SOIL PLATE

SPECIFICATIONS Steel tubes and soil plates shall be fabricated from steel grade 250in accordance with AS/NZS 1594.

Tubes and plates shall be treated and hot-dip galvanized after fabrication in accordancewith AS 1650. The minimum coating mass shall be 900 g/m2, total both sides.


INTENDED USE Steel tubes and soil plates shall be used in the standard MELTterminal. Soil plates only shall be used in the standard trailing terminal.

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AS/NZS 3845:1999 116


FIGURE F31 SHELF ANGLE

SPECIFICATIONS Shelf angles shall be formed from grade 250 steel in accordancewith AS/NZS 1594.

Shelf angles shall be hot-dip galvanized after fabrication in accordance with AS 1650.The minimum coating mass shall be 900 g/m2, total both sides.


INTENDED USE Shelf angles shall be used in the standard MELT terminal.

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117 AS/NZS 3845:1999

NOTES:


2 Cable shall be minimum∅20, 6 × 19 or 6 × 25 wire strand core or independent wire rope core,galvanized and right regular laid in accordance with AS 3569.

3 Cable shall be supplied with two 36 thick M24 hexagon galvanized steel nuts and two 5 thickgalvanized steel washers.

4 Hexagon nuts shall be in accordance with AS/NZS 1112 (grade 5). Nuts shall be tapped to suitgalvanized thread. Black steel washers, large series in accordance with AS 1237 and shall be hot-dipgalvanized in accordance with AS 1214.

5 All nuts shall be snug tight in accordance with AS 4100.


FIGURE F32 STRUT AND YOKE ASSEMBLY

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AS/NZS 3845:1999 118

SPECIFICATIONS Struts shall be RHS steel grade 350 or equivalent in accordancewith AS 1163.

Yokes shall be steel grade 300 in accordance with AS/NZS 1594.

The beam shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.


INTENDED USE Strut and yoke assemblies shall be used in the standard MELTterminal.

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119 AS/NZS 3845:1999

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2 Cable shall be minimum∅20, 6 × 19 or 6 × 25 wire strand core or independent wire rope core,galvanized and right regular laid in accordance with AS 3569.

3 Cable shall be supplied with two 36 thick M24 hexagon galvanized steel nuts and two 5 thickgalvanized steel washers.

4 Hexagon nuts shall be in accordance with AS/NZS 1112 (grade 5). Nuts shall be tapped to suitgalvanized thread. Black steel washers, large series in accordance with AS 1237 and shall be hot-dipgalvanized in accordance with AS 1214.

5 All nuts shall be snug tight in accordance with AS 4100.


FIGURE F33 CABLE ASSEMBLY

SPECIFICATIONS Cable shall be minimum 20 mm in diameter, 6 × 19 or 6 × 24 wirestrand core or independent wire rope core, right regular lay in accordance with AS 3569.Galvanized, Type A minimum coating mass, in accordance with AS 1650.

Swaged fitting shall be a maximum of 40 mm in diameter, have a breaking strain of200 kN and hot-dip galvanized in accordance with AS 1650. Galvanized nuts shall be inaccordance with AS/NZS 1112.

INTENDED USE Cable assemblies shall be used in the standard MELT and trailingterminal design.

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AS/NZS 3845:1999 120


FIGURE F34 PIPE SLEEVE

SPECIFICATIONS Pipe sleeves shall be manufactured from standard galvanized pipein accordance with AS 1163.

INTENDED USE Pipe sleeves shall be used in anchoring the cable assembly in thestandard MELT terminal.

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121 AS/NZS 3845:1999


FIGURE F35 BEARING PLATE

SPECIFICATIONS Bearing plates shall be manufactured from steel grade HA250 inaccordance with AS/NZS 3678.

Plates shall be treated and hot-dip galvanized after fabrication in accordance withAS 1650. The minimum coating mass shall be 900 g/m2, total both sides.


INTENDED USE Bearing plates shall be used for anchoring the cable assembly to thepost in the standard MELT and trailing terminals.

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AS/NZS 3845:1999 122


FIGURE F36 M16 MUSHROOM HEAD BOLT AND NUT

SPECIFICATIONS Mushroom head splice bolts and oversize nuts (M16 × 30) shall beof property class 8.8 in accordance with AS/NZS 1252.

Mushroom post bolts shall be of property class 4.6 in accordance with AS/NZS 1111.

Hexagon nuts for post bolts shall be of property class 5 in accordance with AS/NZS 1112.

Bolts and nuts shall be hot-dip galvanized in accordance with AS 1214.

The length of thread on mushroom headed bolts shall be such that the nut touches theoval shoulder when tightened by hand.

INTENDED USE M16 × 30 mm bolts and oversize nuts shall be used to—

(a) splice rail elements used in the standard barrier design G4, G9, G9 modified, MB4,MB9 modified, MELT and trailing terminals and structure transitions.

(b) fasten the shelf angle to the steel block in the MELT terminal.

(c) fasten the steel diaphragm to the buffered end section used in the standard MELTterminal.

M16 × 50 mm bolts shall be used for fastening rails to steel C-posts and blocks in thestandard barrier designs G4, G9, G9 modified, MB4, MB9 modified, trailing terminals andstructure transitions.

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123 AS/NZS 3845:1999


FIGURE F37 M16 HEX HEAD BOLT AND NUT

SPECIFICATIONS Bolts shall be of property class 4.6 in accordance withAS/NZS 1111.

Nuts shall be of property class 5 in accordance with AS/NZS 1112.

Bolts and nuts shall be hot-dip galvanized in accordance with AS 1214.

INTENDED USE M16 × 30 bolts and nuts shall be used to fasten—

(a) the steel block to the steel C-post in standard barrier designs G4, G9 modified,MB4, MB9 modified, trailing terminals and structure transitions; and

(b) the anchor plate and trailing ends of the curved bullnose terminal to the W-beamrail used in the standard MELT and trailing terminals.

M16 × 240 bolts and nuts shall be used to fasten—

(i) the W-beam end rail to the No. 1 timber post of the standard MELT terminal; and

(ii) the steel block to the timber post in the standard MELT terminal.

NOTE: See Figure F31 for washers that may be used with these bolts.

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AS/NZS 3845:1999 124


FIGURE F38 M20 HEX HEAD BOLT AND NUT

SPECIFICATIONS Bolts shall be of property class 4.6 in accordance withAS/NZS 1111.

Nuts shall be of property class 5 in accordance with AS/NZS 1112.

Bolts and nuts shall be hot dip galvanized in accordance with AS 1214.

INTENDED USE M20 × 40 bolts and nuts shall be used to fasten the soil plate to thesteel end post used in the standard trailing terminal.

M20 × 220 bolts and nuts shall be used to fasten the soil plate to the steel tubes in thestandard MELT terminal.

M20 × 300 bolts and nuts shall be used to fasten the yoke assembly to the steel tubes inthe standard MELT terminal.

NOTE: See Figure F31 for washers that may be used with these bolts.

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125 AS/NZS 3845:1999


FIGURE F39 RECTANGULAR PLATE AND ROUND WASHER

SPECIFICATIONS Washers shall be made of steel and shall be hot-dip galvanized inaccordance with AS 1650.

INTENDED USE Rectangular plate washers shall be used with the post bolt at theleading and trailing posts in the standard MELT and trailing terminals.

M20 round washers shall be used with the bolts fastening the soil plate and yokeassembly in the standard MELT.

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Documents

AS3845 - Road Safety Barrier System