AS3845 - Road Safety Barrier System

AS/NZS 3845:1999

Australian/New Zealand Standard™

Accessed by GHD PTY LTD on 05 Mar 2012

Road safety barrier systems

AS/NZS 3845:1999 This Joint Australian/New Zealand Standard was prepared by Joint Technical Committee CE/33, Road Safety Barrier Systems. It was approved on behalf of the Council of Standards Australia on 9 October 1998 and on behalf of the Council of Standards New Zealand on 12 October 1998. It was published on 5 January 1999.

The following interests are represented on Committee CE/33:

Accessed by GHD PTY LTD on 05 Mar 2012

Australian Automobile Association Australian Motorcycle Council AUSTROADS Composites Institute of Australia Department of Transport, S.A. Galvanizers Association of Australia Institution of Engineers Australia Metal Trades Industry Association of Australia New Zealand Concrete Society New Zealand Employers and Manufacturers Association New Zealand Manufacturers Federation Plastics and Chemicals Industries Association Queensland University of Technology Transit 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 issue of amendments or new editions as necessary. It is important therefore that Standards users ensure 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 Standards Australia and Standards New Zealand Catalogue of Publications; this information is supplemented each month by the magazines ‘The Australian Standard’ and ‘Standards New Zealand’, which subscribing members receive, and which give details of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Joint Standards, addressed to the head office of either Standards Australia or Standards New Zealand, are welcomed. Notification of any inaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should be made without 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.

AS/NZS 3845:1999

Australian/New Zealand Standard™ Road safety barrier systems

Accessed by GHD PTY LTD on 05 Mar 2012

First published as AS/NZS 3845:1999.

Published jointly by: Standards Australia 1 The Crescent, Homebush NSW 2140 Australia Standards New Zealand Level 10, Radio New Zealand House, 155 The Terrace, Wellington 6001 New Zealand ISBN 0 7337 2293 8

AS/NZS 3845:1999

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PREFACE This Standard was prepared by the Joint Standards Australia / Standards New Zealand Committee 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 of performance;

(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 are deemed to comply with this Standard. This Standard describes a means of evaluating road safety barrier systems, based on the best practices identified by the Committee. The National Cooperative Highway Research Program (NCHRP) of the United States Report Number 350 has been adopted as the basis of testing. This Standard is to be read in conjunction with NCHRP Report 350. Reference to CEN Standards is made in NCHRP 350. The Committee notes that the provisions are rudimentary and steps are being taken which may lead to a mutual recognition of tests in future NCHRP and CEN documents. Statements expressed in mandatory terms in notes to tables are deemed to be requirements of this Standard.

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

© 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 by Standards Australia or Standards New Zealand may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia or Standards New Zealand. Permission may be conditional on an appropriate royalty payment. Australian requests for permission and information on commercial software royalties should be directed to the 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 the Standard 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 programs are 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 Standard is 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 commercial contracts 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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AS/NZS 3845:1999

CONTENTS Page FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 1 SCOPE AND GENERAL 1.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . 1.4 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 NOTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 GENERAL REQUIREMENTS FOR ROAD BARRIER 1.7 USE OF OTHER MATERIALS . . . . . . . . . . . . . . . .

....... ....... ....... ....... ....... SAFETY .......

......... 6 ......... 6 ......... 7 ......... 8 . . . . . . . . . 12 SYSTEMS 13 . . . . . . . . . 13

SECTION 2 ROAD SAFETY BARRIER SYSTEMS AND CRASH ATTENUATORS 2.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 DESIGN AND DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 SUPPLY AND ERECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 MAINTENANCE AND DISMANTLING . . . . . . . . . . . . . . . . . . . . . . . . . 2.6 POST-CRASH ASSESSMENT AND REPAIR . . . . . . . . . . . . . . . . . . . . . . SECTION 3 RIGID ROAD SAFETY BARRIER SYSTEMS 3.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 DEVELOPMENT OF DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 ANALYSIS OF STRESSES IN RIGID ROAD SAFETY BARRIER SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 OTHER RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6 RIGID ROAD SAFETY BARRIER PROFILE . . . . . . . . . . . . . . . . . 3.7 FOUNDATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8 COMBINATIONS OF RIGID ROAD SAFETY BARRIER SYSTEM AND RAIL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.9 PROXIMITY OF KERBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.10 PROVISION FOR PEDAL CYCLISTS AND PEDESTRIANS . . . . . 3.11 TERMINALS AND INTERFACE DETAILS . . . . . . . . . . . . . . . . . . 3.12 RIGID ROAD SAFETY BARRIER SYSTEMS IN PUBLIC DOMAIN Accessed by GHD PTY LTD on 05 Mar 2012

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SECTION 4 NON-RIGID ROAD SAFETY BARRIERS 4.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 DESIGN OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS . . . . . . 4.3 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 DEVELOPMENT OF NON-RIGID ROAD SAFETY BARRIER SYSTEMS 4.5 PUBLIC DOMAIN NON-RIGID ROAD SAFETY BARRIER SYSTEMS .

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Page SECTION 5 TESTING 5.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5.2 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5.3 MODIFICATIONS TO NCHRP 350 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

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APPENDICES A BACKGROUND INFORMATION . . . . . B COMMENTARY ON SECTION 2 . . . . . C COMMENTARY ON SECTION 3 . . . . . D COMMENTARY ON SECTION 4 . . . . . E COMMENTARY ON SECTION 5 . . . . . F DETAILS OF ROAD SAFETY BARRIER

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AS/NZS 3845:1999

FOREWORD The intent of this Standard is to provide a framework that unites the many parties involved in the provision of road safety barrier systems and crash attenuators, so that the completed installations provide acceptable performance to the community of road users over 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 of crashes. However, it should be recognized that these devices are themselves a hazard; they have the potential to cause serious injuries. The intention of this Standard is that these devices are only installed at locations where the risk with the device installed is significantly less than the risk without the device.

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The duty of care to be exercised is emphasized. The community of road users includes people in a variety of vehicles which vary in size, mass and methods of propulsion. What should 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 includes pedestrians and those involved in the various construction, operational and maintenance activities that occur within the road reserve. At some sites, the community of road users should be extended to include those whose activities require them to abut the road reserve.

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STANDARDS AUSTRALIA / STANDARDS NEW ZEALAND Australian / New Zealand Standard Road safety barrier systems 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 provide some degree of redirection and containment capability when impacted by a vehicle, or provide controlled absorption of the kinetic energy of a vehicle that is on a collision course 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 systems following a crash.

The Standard also provides details of non-patented road safety barriers that are deemed to comply with this Standard. Where the terms ‘vehicle’ or ‘impacting vehicles’ are referred to in this Standard for the consideration of effects on or by a road safety barrier system, these terms include the following: (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) whether attached 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 barrier systems and road safety barrier systems designed to be readily erected and dismantled. It also applies to devices meant for the applications given in Table 1.2. Accessed by GHD PTY LTD on 05 Mar 2012

This Standard does not apply to the following: (a)

Road safety barrier systems erected for special purposes, such as motor racing, or where special permit vehicles are the design focus.

(b)

Where individual elements of a road safety barrier system are used for special purposes, 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 of road safety barrier system to be installed.

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(f)

AS/NZS 3845:1999

Procedures to locate a road safety barrier system, either longitudinally or transversely, 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 risk management techniques. These techniques shall be used to evaluate the hazards and the associated risks to the community of road users. Where appropriate, the neighbours to a road shall be included in the analysis. The outcome sought shall be a balanced decision that considers the probable benefits, the resources available and the competing investment opportunities. TABLE

1.2

TYPICAL APPLICATIONS Typical applications Installation type

Manoeuvre speed (0 to 15 km/h)

Low speed (15 to 60 km/h)

Arterial, sub-arterial and collector roads

Permanent road safety barriers

Car parks and sites with features requiring protection from incidental impact

Local streets, campuses and roads with restricted design standards

Arterial, sub-arterial and collector roads

Temporary road safety barriers (devices designed to be erected and dismantled quickly)

Work sites in car parks

Work sites on local streets with infrequent movements of vehicles larger than 2000 kg

Work sites on arterial, sub-arterial and collector roads

Crash attenuators

Not appropriate

Gore areas and approaches to toll booths

Gore areas and approaches to toll booths

1.3 REFERENCED DOCUMENTS Standard:

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AS 1163

The following documents are referred to in this

Structural steel hollow sections

1214

Hot-dip galvanized coatings on threaded fasteners (ISO metric coarse thread series)

1302

Steel reinforcing bars for concrete

1303

Steel reinforcing wire for concrete

1304

Welded wire reinforcing fabric for concrete

1348 1348.1

Road and traffic engineering — Glossary of terms Part 1: Road design and construction

1379

Specification and supply of concrete

1604

Timber — Preservative-treated — Sawn and round

1627 1627.5

Metal finishing — Preparation and pretreatment of surfaces Part 5: Pickling, descaling and oxide removal

1650

Hot-dipped galvanized coatings on ferrous articles

1742 1742.3

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

3569

Steel wire ropes

3610

Formwork for concrete COPYRIGHT

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AS/NZS 1111 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 structural engineering

1554 1554.1 1554.5

Structural steel welding Part 1: Welding of steel structures 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 3679.1

Structural steel Part 1: Hot-rolled bars and sections

3750 3750.9

Paints for steel structures Part 9: Organic zinc-rich primer

4360

Risk management

BS 4483

Specification for steel fabric for the reinforcement of concrete

NZS 3112

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 and those below, shall apply. 1.4.1 Agency — the organization responsible for managing that part of the road network where a safety barrier or crash attenuator is proposed.

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1.4.2 Anchor bracket — a bracket used to anchor the cable assembly to the end rail of the modified eccentric loader terminal (MELT) and trailing terminal (TT). 1.4.3 Average recurrence interval (ARI) — a measure of the probability associated with a given flood event. 1.4.4 Bearing plate — a plate to anchor the cable assembly at the first post of the MELT terminal. 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 eccentric loader 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 the Standard, or to a possibility that is available or that might occur. COPYRIGHT

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1.4.9 Clear zone — the horizontal width of space available for the safe use of an errant vehicle which consists of the verge area and is measured from the nearside edge of the left-hand traffic lane. In the case of a divided road, it is also measured from the offside edge 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 a runout 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 a concave installation, or a concave portion of an installation, lies behind the straight line joining the start and finish of the installation, or joining the start and finish of the concave portion of the installation. 1.4.11 convex joining portion

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

1.4.12 Crash — an event or a series of events resulting from a vehicle colliding with another person or object, likely to cause property damage, serious injury or death to the vehicle occupants or to persons struck. 1.4.13 Crash attenuators — devices that prevent an errant vehicle from impacting hazardous objects by gradually decelerating the vehicle to a safe stop or by directing the vehicle away from the hazard. They are often used as the end treatment on the leading end of a road safety barrier system. 1.4.14 Crash testing — conducting a series of full scale impact tests on a road safety barrier system in accordance with recommended guidelines, e.g. NCHRP 350, as appropriate. 1.4.15 Deemed to comply — accepted as complying with the criteria specified in NCHRP 350. 1.4.16 Design horizontal force — an equivalent static force applied horizontally to a road safety barrier system to represent the dynamic force imparted to a road safety barrier system by an idealized and specified design vehicle, impacting the road safety barrier system at a designated speed and angle. 1.4.17 Design life — the length of time during which a road safety barrier system is required to perform its function without any repair. 1.4.18

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

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1.4.19 Dynamic deflection — the largest transverse deflection of a road safety barrier system 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 and trailing ends of road safety barrier systems, which are selected on the basis of traffic speed 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 the travelled way or closer to the travelled way. 1.4.22 Flare rate — ratio of the longitudinal distance to the transverse offset by which a road safety barrier flares away from, or towards, the edge of the travelled way. It can be expressed 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 a point 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 systems with different operating characteristics. It is commonly used to connect a non-rigid road safety 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 or trailing terminals, needed to prevent errant vehicles colliding with a roadside hazard. 1.4.26 Longitudinal road safety barrier system — a road safety barrier system whose primary function is to prevent penetration and to safely redirect an errant vehicle away from a nearside, or an offside hazard. 1.4.27 Maintainer — the team that undertakes all relevant works to maintain the road safety barrier system in a safe working condition. 1.4.28 Manufacturer — the team that manufactures all the components of a recognized road 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 between traffic travelling in opposite directions. 1.4.31 Median road safety barrier system — longitudinal road safety barrier system designed to be impacted from either side. 1.4.32 Modified blockout — a notched blockout used with a thrie-beam road safety barrier 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 travelling in the normal direction of travel. The nearside of a road corresponds to the left-hand of the carriageway when looking in the direction of travel. 1.4.35 Non-gating terminals — terminals that are designed to redirect a vehicle and absorb part of the energy of an impacting vehicle at any point along the terminal without allowing it to pass behind the road safety barrier system. 1.4.36 Non-recoverable slope — a slope that is considered traversable but on which the errant vehicle will continue on to the bottom of the slope. 1.4.37 Non-rigid road safety barrier system — a road safety barrier system where elements are designed to move substantially in a crash, and where energy is absorbed by movement 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 is travelling in the normal direction of travel. It corresponds to the driver’s side of the vehicle. The offside of a road corresponds to the right-hand side of the carriageway when looking in the direction of travel.

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1.4.39 Pipe sleeve — a sleeve to take the cable assembly through the first post of the MELT terminal. 1.4.40 Post — the component supporting the beams of a public domain non-rigid road safety 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 or other intellectual property rights within Australia and New Zealand. 1.4.42 Public domain system — a road safety barrier system that is not the subject of patent 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 or regain 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 is no 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 upon objectives. 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 how often 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 and monitoring risk (see AS/NZS 4360). 1.4.48 Road safety barrier system — a roadside device that provides a physical restriction to penetration of a vehicle in a way that reduces the risk to vehicle occupants and other traffic. Its purpose is to contain or redirect an errant vehicle. It is used to shield roadside obstacles or non-traversable terrain features. Occasionally, it may be used to protect 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 TT terminals. 1.4.51

Should — indicates a recommendation.

1.4.52 Shy-line — the distance from the edge of the travelled way beyond which a roadside object will not be perceived as an immediate hazard by the typical driver, to the extent 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 for installation 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 a rigid barrel or bridge road safety barrier system. 1.4.56 Strut and yoke — used for connecting the first and second posts at ground level in the MELT terminal. 1.4.57 Temporary road safety barrier system — a device designed to be erected and dismantled quickly, used to prevent vehicular access into construction or maintenance work zones. Its purpose is to redirect an impacting vehicle so as to minimize damage to the vehicle and injury to the occupants, while providing worker protection.

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1.4.58 Terminal — the specially designed end pieces of a road safety barrier system. The leading terminal is on the end of the road safety barrier system that faces oncoming traffic and the trailing terminal is on the other end. Terminals are subdivided into the classifications 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 and mass, vehicular impact speed, and vehicular impact angle, that quantifies the impact severity of a matrix of tests. 1.4.60 Test vehicle — a commercially available, production model vehicle or an approved surrogate vehicle used in a crash test to evaluate the impact performance of a test article. 1.4.61 Thrie-beam — the triple corrugated beam component of a public domain nonrigid road safety barrier system. 1.4.62 Transition beam — the corrugated beam used for the changeover from a thriebeam road safety barrier system to a W-beam road safety barrier system. COPYRIGHT

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1.4.63

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UV — ultraviolet radiation.

1.4.64 Verge — the land area between the pavement and another pavement or between a pavement and the property line. 1.4.65 W-beam — the double corrugated beam component of a public domain non-rigid road safety barrier system. 1.4.67 Whole of life cost — the sum of the annualized costs associated with the commissioning, 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 impacting vehicle from colliding with an object behind a road safety barrier system. This includes both the dynamic deflection (if any) and the extra width due to the roll of the impacting vehicle. 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 the 85th 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 expressed in identical units. The dimensional units for length and stress in all expressions or equations are to be taken as millimetres (mm) and megapascals (MPa) respectively, unless specifically noted otherwise. TABLE

1.5

NOTATION USED IN CLAUSE 3.5 Symbol alat

lateral vehicle deceleration

b

width of the vehicle

c

height of the vehicle’s centre of gravity above ground

Flat g

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Description

horizontal force 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

lt

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 comply with this Standard, road safety barrier systems shall be —

To

(a)

supported by technical literature and assembly instructions that clearly illustrate the essential mode of operation and prominently show the test level achieved in crash testing that has been carried out in accordance with this Standard;

(b)

selected and located in accordance with a recognized design procedure that is professionally applied. This procedure shall take account of risk management techniques that address the community of road users and neighbours, which may be affected 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 and execution of repairs; and

(f)

fitted with end treatments and interface devices that are appropriate to the system being used.

Accessed by GHD PTY LTD on 05 Mar 2012

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

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S E C T I O N 2 R O A D S A F E T Y B A R R I E R S 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 crash attenuators. 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 of other parameters that shall be used where specific site information is not available. It provides details of the performance issues that shall be covered in documentation dealing with 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, the site, road safety barrier system and crash attenuator information shall be determined in accordance with Clauses 2.2.2, 2.2.3 and 2.2.4.

Accessed by GHD PTY LTD on 05 Mar 2012

2.2.2 Site information At sites where a road safety barrier system is proposed, the following 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 barrier system, sufficient to allow the likely approach elevation of an errant vehicle to be established.

(g)

Details of the topography at the leading end of the road safety barrier system and any restrictions on the use of gating terminals.

(h)

Associated infrastructure constraints, such as drainage installations, footways and maintenance 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 is proposed, the following shall be obtained, recorded and made available: (a)

The points where the need for a road safety barrier system begins and ends (length of 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 as acoustic devices, delineators, sign support systems, lighting columns and the like.

(i)

Spacing and nature of provisions for access through the road safety barrier system in an emergency or for planned work that requires different traffic arrangements for short 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, the following 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 devices shall be documented. Assessment after a crash shall be carefully carried out and any shortcomings shall be addressed in subsequent designs and any revisions of the documents. ‘Whole of life’ costs shall be used in the evaluation of all road safety barrier systems proposals. These shall include costs to road users and any additional costs borne by people whose access and amenity may be affected. The storage requirements for elements of the road safety barrier systems, which may be replaced during routine maintenance, or after a collision, shall form part of this analysis. NOTE: The appearance of a road safety barrier system may be an important issue at some sites where compatibility with other architectural and geological features is essential.

Sight lines through the road safety barrier system for operational purposes, or to allow glimpses 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 or structures.

Accessed by GHD PTY LTD on 05 Mar 2012

NOTE: For commentary on this Clause, see Paragraph B2.3.1 of Appendix B.

2.3.2 Operational temperature range Road safety barrier systems shall operate over an ambient temperature range of −20°C to +50°C without any reduction in effectiveness. NOTE: For commentary on this Clause, see Paragraph B2.3.2 of Appendix B.

2.3.3 Environment The materials and components used in all road safety barrier systems and end treatments shall be specified. They shall meet the design life defined in Clause 1.4.17. Particular environmental issues, such as snow drifts, glare, accumulation of windborne rubbish, shall also be considered. Modifications that are necessary to cope with crash debris, such as chemical spills, shall be taken into account using a risk management technique. NOTE: For commentary on this Clause, see Paragraph B2.3.3 of Appendix B.

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2.3.4 Flooding Road safety barrier systems or components that cannot be submerged shall be documented. Also, road safety barrier systems, which can be rendered ineffective or which can have a reduced performance as a result of flooding, shall not be used in flood-prone areas. The effect of the road safety barrier system on the flood flows shall be considered. NOTE: For commentary on this Clause, see Paragraph B2.3.4 of Appendix B.

2.3.5 System details All road safety barrier systems and crash attenuators shall be tested in accordance with the procedures specified in this Standard. The following documentation on road safety barrier systems, except those manufactured in cast-in-place concrete, shall be available: (a)

The test level achieved. The technical literature shall provide details of the test certificates, together with details of the site conditions and the road safety barrier configuration at the time it was certified to that test level.

(b)

The working width and the dynamic deflection width that applies to the road safety barrier system at the test level achieved. Where anchors are part of the road safety barrier system, the relationship between the anchorage spacing, the working width and the dynamic deflection width shall be specified. Where the road safety barrier system comprises inter-connected elements, then any relationship between the number of units, the working width and the dynamic deflection width shall be specified.

(c)

The points at the leading and trailing ends of a road safety barrier system where the road safety barrier system becomes effective, and any minimum length requirements. Details shall be provided of any special requirements where long lengths of the road safety barrier system shall be installed.

(d)

The maximum flare rates that apply when the road safety barrier system is located inside the shy-line and beyond the shy-line. This can be expressed as a ratio or as a percentage. Flares at the appropriate flare rate may be used instead of a terminal, provided the flare extends beyond the clear zone.

NOTE: Approved road safety barrier systems that comply with this Standard should be marked with an inscription bearing the following words: THIS ROAD SAFETY BARRIER OR CRASH ATTENUATOR COMPLIES WITH AS/NZS 3845.

The material requirements for cast-in-place concrete road safety barrier systems shall be as specified in Clause 2.4. The profile shapes given in Section 3 shall be used, unless crash testing shows that a different profile gives acceptable results. Accessed by GHD PTY LTD on 05 Mar 2012

NOTE: For commentary on this Clause, see Paragraph B2.3.5 of Appendix B.

2.3.6 Plan details The normal range of horizontal road curve radii, both concave and convex, together with details of the dynamic deflection and working width shall be documented. Details about any combinations of vertical and horizontal geometry that render the road safety barrier system ineffective, or reduce the efficiency of the road safety barrier system, shall be documented. Details shall be provided where this range of applications can be extended by modifications.

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Both temporary and permanent road safety barriers shall be installed so that they are structurally continuous, in accordance with the manufacturer’s specifications. For temporary installations, the continuity shall be able to resist a minimum tensile force of 150 kN for test level 3 and above. NOTES: 1

Lesser values of the minimum tensile force may be used for local and manoeuvrable speed applications.

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 road safety barrier system can be used shall be documented. These details shall be provided where the range of applications can be extended by modifications. Any additional dynamic deflection and working width where installations are on a crest or on sag vertical curves shall be documented. NOTE: For commentary on this Clause, see Paragraph B2.3.7 of Appendix B.

2.3.8 Transverse details available:

For transverse details, the following information shall be

(a)

The design details where the road safety barrier system is to be erected at locations where the cross-fall is less than 4.5% and any different installation procedures required where the cross-fall is greater than or equal to 4.5%. These requirements shall be specified in detail for temporary road safety barrier systems or for any systems that cannot be fixed to the foundation.

(b)

The method of establishing the height of the road safety barrier system at locations where kerbs, gutters, or other changes in level, occur in front of the road safety barrier system.

(c)

The prohibited and undesirable transverse details, such as the permissible position and height of kerbs in front of the road safety barrier system which may affect the working width and dynamic deflection, and create special hazards for pedal and motorcyclists.

(d)

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

NOTE: For commentary on this Clause, see Paragraph B2.3.8 of Appendix B.

Accessed by GHD PTY LTD on 05 Mar 2012

2.3.9 Foundation on natural ground Details of the foundation support necessary for the road safety barrier system to operate effectively shall be specified. Details shall include the following: (a)

The ground conditions that are not appropriate.

(b)

The horizontal extent of foundation support necessary, such as the minimum distance required to hinge points on embankments.

(c)

Installation requirements where elements of the road safety barrier system are installed in excavations, such as the anchor blocks necessary to allow some road safety barrier systems to withstand some tensile loads.

(d)

Soil types that do not suit the road safety barrier system, i.e. soil materials that are likely to reduce the design life of posts and expansive clays that may render concrete 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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The procedures where excavation to the specified depth is not practicable, where driving posts to the required depth cannot be achieved, or where special care is necessary, shall be documented. This shall include sites where rock may be encountered, public utilities are present or where there are site restrictions, such as underground drainage systems and street lighting conduits. NOTE: For commentary on this Clause, see Paragraph B2.3.9 of Appendix B.

2.3.10 Foundations on structures Road safety barrier systems shall allow for expansion and contraction of the supporting structure. The measures that are necessary to allow the road safety barrier system to accommodate the movements of supporting structures under live loads shall be specified. Failure mechanisms shall be identified and largely contained within the road safety barrier system. Failure modes that result in serious damage or destruction of elements of the supporting structure, to the extent that its capacity to perform and its intended function is reduced, shall not be acceptable. Site constraints, such as the straps of reinforced earth walling systems, that require special care shall be documented, and the procedure to be used at sites where interference with such installation is possible shall be specified. Where the strength or the serviceability of an existing structure is to be evaluated for erection of a road safety barrier system, then this Standard shall be applied. The actual properties of the materials in the structure shall be used. NOTE: For commentary on this Clause, see Paragraph B2.3.10 of Appendix B.

2.3.11 End treatment The selected end treatment shall be appropriate to the road safety barrier system used and tested in accordance with this Standard before it is used on the road, to warrant the selected end treatment function as required. As tests are conducted in a controlled environment, the actual site conditions shall be considered when selecting an end treatment. NOTE: For commentary on this Clause, see Paragraph B2.3.11 of Appendix B.

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

Accessed by GHD PTY LTD on 05 Mar 2012

Temporary and permanent road safety barrier installations shall not be distinguished when selecting end treatments. However, where the site is effectively managed, i.e. if the maximum traffic speed is controlled at all times, it shall be permissible to use the lower posted speed limit at temporary installations instead of the normal value of the speed limit. 2.3.12 Interfaces Where different road safety barrier systems adjoin, the interface details shall be designed to achieve a gradual transition in the horizontal stiffness and height. The difference in their horizontal stiffness shall not exceed 40% over a minimum length of 2.5 m. Butting together two road safety barrier systems without proper connections for structural continuity, or only providing end treatments, such as installing adjoining, non-gating terminal systems, shall be prohibited. NOTE: For commentary on this Clause, see Paragraph B2.3.12 of Appendix B.

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 barrier system unless it can be shown by crash testing, clearly documented historical information or 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 on impact, e.g. non-rigid systems.

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Attachment points for road furniture shall not be located in positions where they increase the risk of snagging vehicles, nor shall they have features that create an undue hazard to the community of road users, particularly pedestrians, pedal cyclists and motorcyclists. Sharp edges, pointed elements and dangerous protuberances shall be prohibited. NOTE: For commentary on this Clause, see Paragraph B2.3.13 of Appendix B.

2.3.14 Emergency access For road safety barrier systems, details shall be provided of the method for rapid access through the road safety barrier system in emergencies. Details shall include the following: (a)

Acceptable and prohibited practices.

(b)

Special tools required.

(c)

Estimates of the time and resources necessary to dismantle median road safety barrier system to allow an emergency vehicle to cross.

If a purpose-built road safety barrier system is used (which requires power to open the device), provision shall be made to allow manual operation. For both nearside and off-side installations, permanent emergency access shall only be provided at sites where the distance is sufficient to allow the manoeuvre to be completed with safety. If overlapping is used to provide emergency access, the minimum length, the length of need and flare rates shall be maintained. 2.3.15 Tolerances Fabrication tolerances shall be shown on the drawings. Components that 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 barrier system, unless crash testing, computer simulation or other professionally accepted methods show that the change is acceptable. 2.3.17 Opening in the surface An opening in the surface of the road safety barrier system shall be avoided in areas shown in Figure 2.3.17(1), unless the road safety barrier system complies with full scale crash testing in accordance with this Standard. Means of determining the extent of the opening shall be as shown in Figure 2.3.17(2). NOTE: For commentary on this Clause, see Paragraph B2.3.17 of Appendix B.

2.3.18 Motorcycle road safety barrier system Road safety barrier systems crash-tested for motorcycle impact shall provide smooth unbroken surfaces without sharp edges.

Accessed by GHD PTY LTD on 05 Mar 2012

2.3.19 Impact conditions Road safety barrier systems shall be capable of resisting the vehicle impact parameters given in Table 2.3.19 for the appropriate level without penetration. Whilst penetration of the road safety barrier system by the design vehicle is not acceptable, severe damage and destruction of the elements during the crash is acceptable provided that the damage does not cause accelerations in the impacting vehicle which are outside the limits specified in NCHRP 350. NOTE: For commentary on this Clause, see Paragraph B2.3.19 of Appendix B.

2.4

SUPPLY AND ERECTION

2.4.1 General Road safety barrier systems shall be erected so that the completed work follows the details of the crash-tested installations. Erection practices that do not comply with the drawings and specification shall not be permitted. NOTE: For commentary on this Clause, see Paragraph B2.4.1 of Appendix B.

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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 to damage from twisting and kinking. Critical elements that are vulnerable to damage shall be packaged in a manner that provides protection. NOTE: For commentary on this Clause, see Paragraph B2.4.2 of Appendix B.

2.4.3 Component identification and assembly details To avoid confusion as to the method of assembly, components of the road safety barrier system shall be identified and documented. Components supplied shall be compared with this documentation and missing pieces shall be documented. Any concerns about the identification of a particular element shall be clarified before attempting the erection. NOTE: For commentary on this Clause, see Paragraph B2.4.3 of Appendix B.

TABLE

2.3.19

VEHICLE IMPACT PARAMETERS Test level

Speed

Angle

km/h

degrees

Height of centre of gravity mm

820 C

50

20

550

1 600 C

50

25

550

820 C

50

20

550

2 000 P

50

25

700

820 C

70

20

550

2 000 P

70

25

700

820 C

100

20

550

2 000 P

100

25

700

820 C

100

20

550

8 000 S

80

15

1 250

820 C

100

20

550

36 000 V

80

15

1 850

820 C

100

20

550

36 000 T

80

15

2 050

Vehicle mass (kg) and type

0

1

2

3

4

5

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6

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)

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FIGURE 2.3.17(2)

RESTRICTIONS ON OPENINGS IN ROAD SAFETY BARRIER SYSTEMS

MEANS OF DETERMINING MEASUREMENTS OF OPENINGS IN ROAD SAFETY BARRIER SYSTEMS

2.4.4 General tolerances A road safety barrier system that conforms to the specified tolerances shall be provided. The appearance of the road safety barrier system shall be smooth and even, i.e. free from kinks, in both the vertical and horizontal planes. For all systems, the top of the road safety barrier system shall be within 20 mm of the specified level and 50 mm of the specified location shown on drawings. In general, road safety barrier systems shall be so constructed that the principal axes are vertical. However, if they are installed on a foundation with a cross-fall of more than 4.5%, they may be tilted to be perpendicular to the pavement. In such circumstances, the specification shall be followed. NOTE: For commentary on this Clause, see Paragraph B2.4.4 of Appendix B. COPYRIGHT

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2.4.5 Surface finish A road safety barrier system shall have a surface finish that minimizes the friction between the system and an impacting vehicle. The surface finish shall be uniform, resistant to incidental damage and shall not be affected 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, shall not exceed 20 mm. Any protrusions shall be rounded or similarly treated, to reduce the possibility of snagging the body work of a vehicle or catching at the person or clothing of an individual. After construction, components shall not be left with splits, burrs or sharp edges after construction. Lapping of elements shall be in the direction of the potential path of an errant vehicle. NOTE: For commentary on this Clause, see Paragraph B2.4.5 of Appendix B.

2.4.6 Setting out Before commencing any construction, the start and finish points, and the transverse location of any road safety barrier system, shall be marked. The location of any 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.) NOTE: For commentary on this Clause, see Paragraph B2.4.6 of Appendix B.

2.4.7 Sequence of work Where a road safety barrier system is being constructed on a road that is open to traffic, arrangements shall be made to the sequence of construction to minimize the hazard to road users. Leading terminals and any transitions between road safety barrier systems shall be commissioned at the earliest practicable time. NOTE: For commentary on this Clause, see Paragraph B2.4.7 of Appendix B.

2.4.8 Installation acceptance criteria for posts Where posts form part of the road safety barrier system, they shall be installed to the depth, line and spacing shown on the drawings. The tolerance on post spacing shall be ±25 mm. The tolerance on post height shall be ±20 mm. The tolerance on the verticality of posts shall be ±15 mm, measured at the top of the post. The tolerance on posts rotation shall be ±30 mm, measured as the difference between the point of attachment of the post to the rail and the free position of this same point without the rail attached. After the posts are installed, all elements in the road safety barrier system shall fit together without the need to enlarge any holes or modify any component. The installation process shall not cause damage to the post, such that it reduces the effective operation of the road safety barrier system or its design life, or introduces sharp tearing edges, nor shall it cause damage to any pavement layer located more than 100 mm away from the post.

Accessed by GHD PTY LTD on 05 Mar 2012

The orientation of posts shall be in accordance with the drawing. This shall apply to any block-out pieces that are required by the design. Where the materials in the posts may be affected by rot or attack by termites, the required specifications shall be followed. NOTE: For commentary on this Clause, see Paragraph B2.4.8 of Appendix B.

2.4.9 Construction acceptance criteria for foundations For road safety barrier systems 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 for the interface of the system with the foundation shall be followed.

(c)

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Where the sides of any excavation act as the former for any concrete work, then this shall be neatly done. NOTE: For commentary on this Clause, see Paragraph B2.4.9 of Appendix B.

2.4.10 Construction acceptance criteria for concrete construction Reinforcing steel shall be as shown on the drawings. For road safety barrier systems that are less than 1 m in height, the area of reinforcement shall not be less than a total of 500 mm 2/m length for the horizontal and vertical directions. For road safety barrier systems greater than 1 m in height, the area of reinforcement shall be at least 1000 mm 2/m horizontally in both faces. A design check shall be made to ensure the road safety barrier system shall perform as intended. NOTE: Checks for stresses that result from lifting the device may be appropriate with some designs.

For high-strength concrete, the concrete cover shall be as given in Table 2.4.10(1). At all sites, the minimum clear concrete cover shall be not less than 1.5 times the maximum nominal size of the aggregate, or 1.5 times the diameter of the reinforcing bar being protected. Reinforcing steel shall be supported using concrete or plastic chairs. Pieces of wire, timber, reinforcing steel or coarse aggregate shall not be used to support reinforcing steel. 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 and category 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/m 3. Road safety barrier systems made of concrete shall be constructed using either pre-cast segments, placing concrete in fixed forms, or by slip forming. Concrete shall be placed in a continuous operation between construction joints. Fresh concrete shall not be placed against 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 be tested 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 surfaces shall be finished to a class finish in accordance with AS 3610 or to a Class F4 finish in accordance with NZS 3114. Expansion joints shall be constructed as shown on the drawings. Expansion joints shall be straight, 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 be 50 ±5 mm deep. Spacing shall be at the specified interval but not more than 6.0 m apart.

Accessed by GHD PTY LTD on 05 Mar 2012

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 curing compound applied to all exposed surfaces. The process to cure the concrete for the time specified 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 than controlled shrinkage cracks. Sampling, testing and assessment of the strength of concrete shall be carried out in accordance 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). NOTE: For commentary on this Clause, see Paragraph B2.4.10 of Appendix B.

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TABLE

2.4.10(1)

COVER REQUIREMENTS FOR CONCRETE Minimum cover for concrete strength (see Note 2) (mm)

Exposure classification (see Note 1)

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 Tolerance (mm)

Item (a)

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

5 0 to +5

(b) Variation of cross-section (c)

−5 to +5

Variation from vertical or specified batter

5 in 2.5 m (1 or 500)

(d) Variation from grades indicated on drawings (e)

(f)

2.5 in 2.5 m (1 or 1 000)

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

25 ≤10

Departure from alignment

5

(g) Irregularities

2.5 in 2.5 m

TABLE

2.4.10(3)

TOLERANCES FOR PRE CAST CONCRETE ELEMENTS Tolerance (mm)

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Item (a)

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

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

5 0 to +5 0 to +3

Squareness of ends (deviation from a place perpendicular to the longitudinal axis)

≤3

(d) Overall length

3

(e)

3

Profile in horizontal plane (bow)

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AS/NZS 3845:1999

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 of determining the remaining period for which the system shall be fit for use.

(b)

Documentation on installation procedures to optimize the life of the plastic component.

(c)

Repair methods to be used where plastics are damaged.

(d)

Data on the flammability of the plastics used and any special precautions necessary to reduce the risks associated with fire.

(e)

Disposal procedures at the end of the period for which the system shall be fit for use.

NOTE: For commentary on this Clause, see Paragraph B2.4.11 of Appendix B.

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

Steel components shall

Metals that have less than 16% tested elongation shall not be used in elements subject to impact by traffic, unless crash testing has shown that the material is acceptable. All structural steel shall comply with AS/NZS 3678 or AS/NZS 3679.1, as appropriate. Welds shall be category SP in accordance with AS/NZS 1554.1 Welds subject to alternating tensile or compressive stresses at 500 000 cycles or more shall comply with AS/NZS 1554.5. Other metal materials, not specified herein, shall comply with the appropriate Australian or New Zealand Standard. If such a Standard is not available, they shall comply with Specifications or Standards issued by bodies accredited by an authority, such as the American 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c)

Irregularities in alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 mm in 3 m.

(d)

Variation in joint gap width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 mm. 3 mm.

NOTE: For commentary on this Clause, see Paragraph B2.4.12 of Appendix B.

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2.4.13 Acceptance criteria At the end of installation, each road safety barrier system shall be reviewed to ensure that the design expectations have been met. Issues to be addressed 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-loaded to the values specified by the manufacturer. Splices shall be checked to ensure they are in the correct position with respect to traffic direction. Foundations shall be structurally adequate for the imposed loadings, both horizontal and vertical. Products that require ballast shall be filled. Likely performance of the road safety barrier system with respect to the design vehicle, its speed and its angle of impact shall 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 of resistance. Adequate recovery areas shall be provided behind gating terminals and shall be free from significant obstacles. Terminal offsets shall be in accordance with the drawings.

(c)

Functional adequacy Road safety barrier systems shall be installed at the right height with respect to the impacting vehicle adopted for the purposes of the design. COPYRIGHT

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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 need shall be properly located. Flare rates, where used, shall be appropriate. Working width and dynamic deflection width requirements shall be met. The need for pedestrian 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 tensioned to the values specified by the manufacturer.

(e)

Site suitability Where anchors are an essential part of the road safety barrier system, the site conditions shall be appropriate for the installation. Sight distance shall remain appropriate. Delineation shall be appropriate and properly installed. General site safety issues shall be addressed, especially the needs of other road users.

After any roadwork activity in the vicinity of a road safety barrier system, a check shall be made in accordance with Items (a) to (e) of this Clause. NOTE: For commentary on this Clause, see Paragraph B2.4.13 of Appendix B.

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 safety barrier 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 may have occurred which will alter the frequency of inspections required, or the elements to be inspected. Particular attention shall be given to any changes in the volume of traffic or its speed, and whether the vehicle adopted for the original design remains appropriate. Where reverse direction crashes are a feature of the installation, an assessment shall be made to ensure that the original design criteria remain valid.

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2.5.2 Vandalism Special measures shall be provided where a road safety barrier system is located in an area where vandalism is likely and risk management analysis shows that such measures are warranted. Issues such as damage by sharp objects or knives, drainage of any ballast, flammability, deliberate modification to increase the hazard and ease of removal of critical elements shall be taken into consideration. The surface shall resist damage from common solvents, especially petrol. 2.5.3 Cleaning Routine maintenance for removal of road grime and graffiti shall form part of the documentation. In cases where particular solvents damage the road safety barrier system, documentation on cleaning procedures shall be provided. NOTE: Cleaning practices could affect the performance of the road safety barrier system because of the possibility that they may disable, or substantially reduce the effectiveness of elements 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 the case of plastic road safety barrier systems or sand in the case of barrel terminals, to function to the required test level, a means of determining whether sufficient ballast is present during a drive by inspection shall be provided. Installations shall be checked for any unacceptable decrease in road safety, e.g. ballast spill onto the carriageway. COPYRIGHT

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2.5.5 General site maintenance The installation shall be examined to see whether there are site issues that have increased the risk of a collision with the device, or the severity of such a collision. Particular attention shall be given to debris that may reduce the 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 the road, 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 review shall be carried out to ensure that the need for the system remains and that the manufacturer’s operational specifications shall be complied with. The criteria specified in Clause 2.4.13 may be used to make this assessment. Dismantling of the road safety barrier system shall be in accordance with the manufacturer’s specifications. NOTE: The manufacturer should be contacted if elements of the road safety barrier system are to 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 be prepared 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 as is practicable after a crash. Crash sites shall not be left in a condition that increases the risk to other traffic to unacceptable levels. This shall be determined using risk analysis techniques. 2.6.2 Damage Road safety barrier systems shall permit the ready replacement of all elements that are damaged during a crash. As well, the replacement of components at the end of their design life shall be practicable and cost-effective. 2.6.3 Refurbishment Road safety barrier systems shall be inspected on a routine basis to identify incidental damage that has occurred in unreported crashes. Decisions to leave damaged components in service shall be documented. NOTES: The document, which contains decisions to leave components in service, is to be prepared by 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 to allow resources to be allocated to other road safety barrier systems that are judged to have a higher priority.

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3

R I G I D R O A D S A F E T Y S Y S T E M S

B A R R I E R

3.1 SCOPE This Section applies to road safety barrier systems that are designed so that there will be no movement of the device, other than elastic strain, during a crash involving the design vehicle. It includes road safety barrier systems that have rails, or similar components, that are attached to substantial bases which could be taken as elements of a rigid road safety barrier system. This Section also provides details of public domain systems that are deemed to comply with 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 road safety barrier systems. Rigid road safety barrier systems shall only be installed at locations where the hazard and risk associated with impacting the device are significantly less than the hazard and the risk of impacting the items being protected. NOTE: For commentary on this Clause, see Paragraph C3.2 of Appendix C.

3.3

DEVELOPMENT OF DESIGN

NOTE: For commentary on this Clause, see Paragraph C3.3 of Appendix C.

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3.3.1 General The procedure for developing a design for a rigid road safety barrier system shall be as follows: (a)

Determine the desirable outcome of the installations when it is impacted by the design vehicle at the nominated speed and impact angle. Pay particular attention to the 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 satisfy the outcomes specified in Item (a).

(c)

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

(d)

Consider the likely outcome when the proposed road safety barrier installation is subjected 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 design vehicle, the following issues shall be considered: (a)

Other crash vehicles Consider the outcome when the road safety barrier system is hit by a vehicle that is either lighter and lower, lighter and higher, or considerably heavier and higher than the design vehicle.

(b)

Other crash angles and speeds Consider the outcome when the impact angle of the design vehicle is larger than the nominated impact angle. The probable speeds associated with these angles shall be used.

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3.4 ANALYSIS OF STRESSES IN RIGID ROAD SAFETY BARRIER SYSTEMS Analysis 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 safety barrier shall resist the transverse longitudinal and bending moment loadings determined for the selected test level in accordance with Section 2. When impacted by the design vehicle at the specified speed and angle, destruction of elements of the system is acceptable. However, penetration is not acceptable. Where the rigid road safety barrier system is placed on a structure, there shall be sufficient resistance in the foundations to allow the failure mode to remain within the road safety barrier system. In the absence of a more rigorous analysis, the ratio between the structural capacity of the foundation and the capacity of the rigid road safety barrier system shall be not less than 1.2. NOTE: For commentary on this Clause, see Paragraph C3.4 of Appendix C.

3.5 OTHER RESULTS Longitudinal road safety barrier systems shall be designed and constructed to retain the idealized design vehicle for the particular site, e.g. car, truck or bus 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 the type of vehicle and may be higher than the effective height of a road safety barrier system. A vehicle will just roll over if the following condition applies: M o = ma lat (c − h eff) − mg (

b − ∆) − µ m g h eff 2

0

. . . 3.5(1)

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 ≈

1.5 (IS x)

. . . 3.5(2)

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)

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≥

. . . 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 be used.

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 impact severity, in kilojoules (see NCHRP 350) COPYRIGHT

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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 and flexible, k shall be analysed

FIGURE 3.5

DIMENSIONS

3.6 RIGID ROAD SAFETY BARRIER PROFILE The profile of a rigid road safety barrier system shall be either that shown to be acceptable by crash testing at design loads or 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 VCB shape shall be as shown in Figure 3.6(2). 3.7 FOUNDATION The foundation of a rigid road safety barrier system shall be of sufficient strength to resist both the shear forces and the bending moments applied during a crash with the design vehicle. Depending on the nature of the road safety barrier system, some resistance to the vertical loads may be necessary.

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NOTE: For commentary on this Clause, see Paragraph C3.7 of Appendix C.

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

The design shall incorporate a failure mechanism, which means that the anchors will be the first point of failure followed by the posts and then the rail. The traffic face of a rail shall be vertically aligned as shown in Figures 3.6(1) and 3.6(2), unless crash 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 the rail.

(d)

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

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DIMENSIONS IN MILLIMETRES

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FIGURE 3.6(1)

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

DIMENSIONS IN MILLIMETRES

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 located adjacent to kerbs. Where this is not possible, kerbs shall be removed unless the distance from 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 a warrant to provide facilities for pedal cyclists or pedestrians, rails shall be provided in accordance with Clause 2.3.13. 3.11 TERMINALS AND INTERFACE DETAILS Only tested details and devices shall be used as terminals or to connect rigid road safety barriers to road safety barrier systems with different operating characteristics. 3.12 RIGID ROAD SAFETY BARRIER SYSTEMS IN PUBLIC DOMAIN Details of a design solution for type F and type VCB road safety barriers that are deemed to comply 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 are deemed 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 a rigid road safety barrier system that are deemed to comply shall be as shown in Figures F7, F 8 and F9 of Appendix F.

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NOTE: For commentary on this Clause, see Paragraph C3.12 of Appendix C.

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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.

DIMENSIONS IN MILLIMETRES

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

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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.

DIMENSIONS IN MILLIMETRES

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. DIMENSIONS IN MILLIMETRES

FIGURE 3.12(3)

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

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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. DIMENSIONS IN MILLIMETRES

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.

2

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

DIMENSIONS IN MILLIMETRES

PRECAST 3 m STANDARD LENGTH UNIT (MEETS TEST LEVEL 3)

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FIGURE 3.12(5)

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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. Only reinforcement directly related to the bridge rail is shown. Bridge decks should be designed to develop the full strength of the bridge railing.

6

Where rails are provided on top of these barriers for additional crash protection, they are to be aligned with 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, then these 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 being staggered 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. DIMENSIONS IN MILLIMETRES

FIGURE 3.12(6)

820 HIGH VCB ROAD SAFETY BARRIER SYSTEM

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NOTES: 1

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

2

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

3

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

4

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

5

Where rails are provided on top of these barriers for additional crash protection, they are to be aligned with 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, then these rails may be set back from the traffic face.

6

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

7

A road safety barrier is deemed to comply at test level 3. DIMENSIONS IN MILLIMETRES

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.

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. Only reinforcement directly related to the bridge rail is shown. Bridge decks should be designed to develop the full strength of the bridge railing.

6

Where rails are provided on top of these barriers for additional crash protection, they are to be aligned with 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, then these 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 being staggered 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. DIMENSIONS IN MILLIMETRES

FIGURE 3.12(8)

1100 HIGH VCB ROAD SAFETY BARRIER SYSTEM COPYRIGHT

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NOTES: 1

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

2

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

3

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

4

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

5

Where rails are provided on top of these barriers for additional crash protection, they are to be aligned with 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, then these rails may be set back from the traffic face.

6

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

7

A road safety barrier is deemed to comply at test level 3. DIMENSIONS IN MILLIMETRES

FIGURE 3.12(9)

1100 HIGH TYPE ‘F’ ROAD SAFETY BARRIER SYSTEM COPYRIGHT

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S E C T I O N

4

N O N - R I G I D R O A D B A R R I E R S

S A F E T Y

4.1 SCOPE This Section sets out the requirements for non-rigid road safety barrier systems in terms of the following: (a)

Development of design The design of non-rigid road safety barrier systems for particular impact conditions including preparation of the specification for the installation of non-rigid road safety barrier systems.

(b)

Installation

(c)

In-service inspection, maintenance and disposal The inspection, maintenance and disposal of in-service non-rigid road safety barrier systems.

(d)

Systems development barrier systems.

The installation of non-rigid road safety barrier systems.

The development of new types of non-rigid road safety

This Section also contains details of selected public domain non-rigid road safety barrier systems 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 The procedure for the development of the design for a non-rigid road safety barrier system shall 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 to provide the protection as specified in Step (a).

(c)

Determine the desirable outcomes from the installation when impacted by the range of vehicles at the nominated speed and impact angle, particularly dynamic deflection and 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 particular location.

(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.

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4.3 INSTALLATION Prior to installing a non-rigid road safety barrier system, the site shall 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, requires modification; 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 with Clause 4.4.2. Non-rigid road safety barrier systems with tensioned wire ropes shall comply with Clause 4.4.3. NOTE: For commentary on this Clause, see Paragraph D4.4.1 of Appendix D. COPYRIGHT

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All non-rigid road safety barrier systems

4.4.2.1 Intended function The following shall be determined when developing non-rigid road 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 is significantly changed when the impacts are more severe, then all modes shall be specified.

(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, if appropriate, the manner in which the road safety barrier system is to be transitioned to rigid road safety barrier systems or structures.

(e)

The range of physical environments in which the road safety barrier system is capable of being used.

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

4.4.2.2 Practical usefulness systems, ensure that —

For the practical usefulness of non-rigid road safety barrier

(a)

appropriate crash-safe methods shall be available for terminating the non-rigid road safety barrier systems and for the changeover from non-rigid road safety barrier systems 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 common site conditions.

Documentation of how the non-rigid road safety barrier systems interact with common site conditions shall be made available. NOTE: For commentary on this Clause, see Paragraph D4.4.2.2 of Appendix D.

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 do not fracture nor develop sharp edges.

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4.4.3.2 Rope tension, anchorage and tension devices The design of the non-rigid road safety barrier system including rope anchorage, tension devices and the manufacturing process for the whole system shall be as follows: (a)

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

(b)

A sudden release of tension in the rope shall be prevented if one particular tensioning device is released whilst leaving the other tensioning devices fully tensioned.

(c)

All the components of the non-rigid road safety barrier system shall remain in their correct location relative to each other. NOTE: For commentary on this Clause, see Paragraph D4.4.3.2 of Appendix D.

4.4.3.3

Rope diameter

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

NOTE: For commentary on this Clause, see Paragraph D4.4.3.3 of Appendix D.

4.4.3.4 Rope manufacture Ropes and the wire from which the rope is made, shall be manufactured 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 abrasive environments If it is intended to use non-rigid road safety barrier systems in corrosive or abrasive environments, the design shall be such as to — (a)

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enable easy inspection of the wire ropes, associated anchorages and tension devices so 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 safety barrier 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 in Table 4.5.1. Details of the non-rigid road safety barrier systems, their assembly and specification of their parts are shown in the relevant figures of Appendix F. The public domain non-rigid road safety barrier systems shall be deemed to comply with the requirements of test level 3. NOTE: For commentary on this Clause, see Paragraph D4.5.1 of Appendix D.

4.5.2 Area between traffic lane and non-rigid road safety barrier systems The area between the traffic lane and the front face of the non-rigid road safety barrier system shall be a plane, trafficable surface with a cross-fall less than or equal to 1 in 10. The area from the face of the road safety barrier to the full extent of the working width shall be in accordance with the manufacturer’s specification. NOTE: For commentary on this Clause, see Paragraph D4.5.2 of Appendix D.

4.5.3 Location and orientation of steel blockouts, posts and nailing laps Steel blockouts and posts shall be located and orientated so as to minimize any potential for errant vehicles, or all other road users, to snag on that open face or by the laps of rails. NOTE: For commentary on this Clause, see Paragraph D4.5.3 of Appendix D.

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

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

Excavate or pre-bore a hole in the ground at least 400 mm in diameter with the hole diameter 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 the hole, or be closer to the side of the hole further from the traffic lane from which most errant vehicles will originate.

(c)

Backfill around the posts with clean, well-graded, non-cementitious granular material, compacted so that — (i)

if a horizontal force of 1 kN is applied in any direction to within the top 200 mm of a post before the rail is secured, movement of the post at ground level 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.

NOTE: For commentary on this Clause, see Paragraph D4.5.4 of Appendix D.

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AS/NZS 3845:1999

4.5.5 Anchorage of the W-beam or thrie-beam The W-beam or thrie-beam shall be anchored at both ends of the non-rigid road safety barrier system installation in such a manner that the full tension of the W-beam or thrie-beam can be developed if the nonrigid road safety barrier system is hit by a vehicle one panel from the end of the installation. Where cable terminals are used, the nuts at both ends of each cable shall be tightened to 50 Nm. NOTE: For commentary on this Clause, see Paragraph D4.5.5 of Appendix D.

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

Accessed by GHD PTY LTD on 05 Mar 2012

NOTE: For commentary on this Clause, see Paragraph D4.5.6 of Appendix D.

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TABLE

4.5.1

TYPES OF PUBLIC DOMAIN NON-RIGID ROAD SAFETY BARRIER SYSTEMS Type

G4

G9

G9 (Modified)

MB4

Post spacing (m) 2.0

2.0 (see Item (c))

2.0

2.0

Dynamic deflection (m)

Remarks

Index to standard component drawings in Appendix F Item

Figure

1.0 (2 000 kg vehicle at 100 km/h; and 25°)

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

W-beam and stiffener C-post Blockout Splice bolt and nut Bolt and nut (nail to post) Block bolt and nut W-beam structure connector

F12 F16 F21 F36 F36 F37 F27

0.6 (2 000 kg vehicle at 100 km/h; and 25°)

(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 stiffener C-post Blockout W-thrie transition beam Thrie-beam structure connector Splice bolt and nut Post bolt and nut Block bolt and nut

F14 F17 F23 F15 F27

Thrie-beam and stiffener C-post Modified blockout W-thrie transition beam Thrie-beam structure connector Splice bolt and nut Post bolt and nut Block bolt and nut

F14 F17 F23 F15 F27

W-beam and stiffener C-post Blockout Splice bolt and nut Post bolt and nut Block bolt and nut

F12 F21 F16 F36 F36 F37

1.0 (8 000 kg vehicle at 100 km/h; and 15°)

0.5 (2 000 kg vehicle at 100 km/h; and 25°)

(a) Thrie-beam steel rail system with modified blockout (b) Can be used with G4 system with W-thrie transition beam (c) Anchored terminals are essential

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

F36 F36 F37

F36 F37 F37

(continued) COPYRIGHT

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AS/NZS 3845:1999

TABLE 4.5.1 (continued)

Type

MB9 (Modified)

Modified eccentric loader terminal (MELT) 8.0 m

Post spacing (m) 2.0

Dynamic deflection (m) 0.5 (2 000 kg vehicle at 80 km/h and 25°

NA

Remarks

Index to standard component drawings in Appendix F Item

Figure

(a) Thrie-beam steel rail median system with modified blockouts (b) Can be used with MB-4 system with W-thrie transition beam (c) Anchored terminals are essential

Thrie-beam and stiffener C-post Modified blockout Splice bolt and nut Post bolt and not Block bolt and nut

F14 F17 F23 F36 F36 F37

(a) Gating terminals for general use with G4 W-beam system (both loading and trailing) (b) Can be used with G9 and G9 (modified) thrie-beam system (c) Batter slope to be traversable and free from fixed object hazards (d) Flare is critical (e) Use as trailing terminal when barrier is within clear zone of opposing traffic

General arrangement drawing W-beam end rails Timber posts Steel blockout Strut and yoke assembly Shelf angle Soil tube and plate Buffered end section and diaphragm Anchor plate Cable assembly Post sleeve Bearing plate Splice bolt and nut Post bolt and nut Rectangular washer Yoke bolt and nut Soil plate bolt and nut Anchor plate bolt and nut

F11 F13 F19 F21 F32 F31 F30 F25 F29 F33 F34 F35 F36 F37 F39 F38 F38 F36 (continued)

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TABLE 4.5.1 (continued)

Type

Post spacing (m)

Dynamic deflection (m)

Remarks

Index to standard component drawings in Appendix F Item

Figure

Trailing terminal (TT) 4.0 m

NA

(a) Trailing terminal for general use with G4 W-beam system (b) Can be used with G9 and G9 (modified) thrie-beam system using a transition to G4 (c) Batter slope to be reasonably traversable and free from fixed object hazards (d) System not to be used within clear zone of opposing traffic

General arrangement drawing W-beam end rail C-post Blockout End post Soil plate Shelf angle Buffered end section Anchor plate Cable assembly Bearing plate Splice bolt and nut Post bolt and nut Rectangular washer Soil plate bolt and nut Anchor plate bolt and nut

F10 F13 F17 F21 F18 F30 F31 F25 F29 F33 F35 F36 F37 F39 F38 F36

Structure transition 6.0 m

NA

Transition system for barrier designs G4 and G9 (modified) to rigid structures such as type F concrete barriers and bridge parapets

General arrangement drawing Thrie-beam C-post Blockout W-thrie transition beam C-post Blockout Structure connector Splice bolt and nut Post bolt and nut Block bolt and nut

F10 F14 F17 F23 F15 F16 F21 F27 F36 F36 F37

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S E C T I O N

5

AS/NZS 3845:1999

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 in components.

(c)

Verification of performance of a road safety barrier system due to site specific issues, such as kerbs and drainage ditches in front of or within the working area of the road safety barrier system, and specific application requirements, such as posts in 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 of NCHRP 350 have been modified by the addition of a lower test level (TLO), as specified in Clause 5.3. With the exception of Item (c) of Clause 5.1, test procedures shall not be designed to replicate any specific set of circumstances. Rather, the tests shall be arranged so that they provide 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 barrier system can be high and performance can only be gauged when as many factors as possible are kept sensibly constant.

5.3

MODIFICATIONS TO NCHRP 350

5.3.1 Chapter 1 NCHRP 350.

There

are

no

modifications

to

Chapter 1,

Introduction,

of

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

TABLE

5.3.2(1)

MODIFICATIONS TO CHAPTER 2 OF NCHRP 350

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NCHRP 350 Clause

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 in Table 5.3.2(2) of this Standard, to Table 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 inertial Dummy Maximum ballast Gross static

1 600 ±45 75 160 1 675 ±45

Dimensions (mm) Wheelbase Front overhand Overall length Track width

2 800 950 4 800 1 500

±100 ±100 ±200 ±200

Centre of mass location (mm) Aft of front axle Above ground

1 250 ±150 550 ±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 shall be as given in Table 5.3.3(1). References to support structures, breakaway utility poles and truck-mounted attenuators shall be deleted. TABLE

5.3.3(1)

MODIFICATIONS TO CHAPTER 3 OF NCHRP 350

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NCHRP 350 Clause

Heading

Modification

3.1

General

Add 1 600C vehicle

3.2

Test matrices

Add Tables 5.3.3(2) and 5.3.3(3) of this Standard to Tables 3.1 and 3.2 of NCHRP 350

3.3

Tolerances on impact conditions

Add 1 600C vehicle, as given in Table 5.3.3(4) of this Standard, to Table 3.5 of NCHRP 350

3.4

Impact point for redirective devices

No change

3.5

Side impact tests

No change

TABLE

5.3.3(2)

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

Test level

Barrier section

Test designation

Vehicle

Nominal speed (km/h)

Nominal angle (deg)

0

Length of need

1-10 1-12

820C 1 600C

50 50

20 25

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Impact point

Evaluation criteria (see Table 5.3.2(1))

(b) (b)

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

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TABLE

AS/NZS 3845:1999

5.3.3(3)

ADDITIONS TO TABLE 3.2 OF NCHRP 350 TEST MATRIX FOR TERMINALS AND CRASH ATTENUATORS Impact conditions Test Level

Feature type

Test designation

Vehicle

Nominal speed (km/h)

Nominal angle (deg)

Impact point

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

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

Feature

Terminals and redirective crash attenuators

0

Non-redirective crash attenuators

TABLE

Evaluation criteria (see Table 5.2.2(1))

5.3.3(4)

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

Speed 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 350 shall be as given in Table 5.3.4(1).

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TABLE

5.3.4(1)

MODIFICATIONS TO CHAPTER 4 OF NCHRP 350 NCHRP 350 Clause

Heading

Modification

4.1

Typical parameters

No change

4.2

Pretest parameters

Add 1 600C vehicle to any listing of ‘C’ vehicles

4.3

Test parameters

No instrumentation is required on the 1 600C vehicle for test level 0 Table 4.1 of NCHRP 350 has the measurements of working width added as given in Table 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 350 KEY TEST PARAMETERS Recommended measurement tolerance

Parameter Maximum transverse displacements of vehicle body beyond face of barrier at point of maximum dynamic deflection

5.3.5 Chapter 5 NCHRP 350.

Acceptable measurement technique

±5.0 cm

High speed cine

Remarks Minimum film speed of 200 frames/sec overhead camera

There are no modifications to Chapter 5, Evaluation Criteria, of

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

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TABLE

5.3.6

MODIFICATIONS TO CHAPTER 6 OF NCHRP 350 NCHRP 350 Clause

Heading

6.1

General reporting recommendations

Add 1 600C vehicle to the 700C and 850C vehicles

6.2

Electronic data

Not applicable

Modification

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

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APPENDIX

AS/NZS 3845:1999

A

BACKGROUND INFORMATION (Informative) Road safety barrier and crash attenuator systems are installed on the verges of roads to reduce the hazards associated with road use. These systems can be installed on a permanent 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 or more 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 the vehicle.

By installing devices that dissipate large amounts of kinetic energy by the mechanisms specified in Items (a) to (e), considerable care should be taken to ensure that the energy transfer 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 rolling and yawing, which may result in severe injuries to vehicle occupants. Road safety barrier systems that fail to control the exit path may unnecessarily involve nearby vehicles in a crash.

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The provision of appropriate systems that substantially reduce the level of hazard on a road only occurs when there is a close communication and a cooperative approach between 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 possibility that the installation may not perform in the manner intended. In some circumstances, the installation may increase the hazard. It is intended that all parties involved in the provision of the devices communicate effectively to ensure that there is real reduction in the roadside hazard for all users. It is expected that owners of these devices will have a realistic understanding of a likely performance associated with installing a particular system at the site in question. It should not be expected that the system will provide complete protection over the wide range of variables that could apply in a crash, such as vehicle mass, dimensions, speed and orientation of the vehicle on impact. It should also be recognized that the system itself introduces a hazard to the travelling community. It should be ensured that the system selected provides the community with an investment that improves safety at the site and an appropriate balance with the need for investment in such systems on the rest of the road network.

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

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

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APPENDIX

AS/NZS 3845:1999

B

COMMENTARY ON SECTION 2 (Informative) B2.1 SCOPE Great care should be exercised in selecting the sites to install, repair or to 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 ‘risk management’ techniques to make informed choices about selecting the sites. Details of risk management techniques are contained in AS/NZS 4360. However, Simon Chapman, Associate Professor of Public Health and Community Medicine at the University of Sydney has cautioned experts when applying risk management techniques. He is of the opinion that there is a tendency for experts to systematically overestimate the risk when the hazard is high and underestimate the risk when the hazard is low. Chapman points out that the community tends to focus on ‘outrage’. Outraged people pay little attention to scientific data; the media find outrage more news worthy than statistics. A climate of outrage thus overestimates the risk when the outrage is high and underestimates the risk when outrage is low.

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Some issues that have to be considered when assessing whether outrage may be an issue include the following: (a)

Voluntary risk versus coerced risk Outrage is higher when people are forced to take a risk instead of accepting the risk by their own volition.

(b)

Natural risk versus industrial risk The community may be more upset by installations that are built, such as a road safety barrier, than hazards that naturally occur, such as trees on the side of the road.

(c)

Familiar risk versus exotic risk than familiar installations.

(d)

‘Not dreaded’ risk versus ‘dreaded risk’ Some issues have generated an iconography in literature that instil dread in people. Nuclear radiation is an obvious case.

(e)

Chronic risk versus catastrophic risk Communities fear low probability, high magnitude risk more than high probability low magnitude risk. Bus crashes are more feared than car crashes.

(f)

Knowable risk versus not knowable risk The potential for dread can often be increased when the issues are hard to understand.

(g)

Morally irrelevant risk versus morally relevant risk The community tends to have tolerance for outrage-inducing problems where the issue is seen as morally irrelevant.

New devices (exotic) are treated more suspiciously

With respect to the type of road safety barrier system to be selected, this Standard does not attempt to make any comparison between the systems available. The variety of existing systems, and the number of new systems that are becoming available, would make this impractical. However, the crash test results required to be provided as part of this Standard should be used to assist in the selection. But crash testing is only part of the process necessary to provide an effective road safety barrier system on the road. A climate of 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 to operate near the operating boundaries of any one of the many parameters that affect performance.

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With respect to current installation, the wide variation in type, age and general condition of road safety barrier systems should be noted. The intention of this Standard is not to create a demand to remove all examples of superseded practice from the roadside. It is anticipated that equipping the road network with road safety barrier systems that comply with this Standard will take many years to achieve. It is essential that due thrift be exercised 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 sites with 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 cycle associated with a Standard. During the period that will elapse before a review of this Standard occurs, there will be many advances in technology, changes in the Australian and New Zealand vehicle fleet and changes in community expectations. In applying this Standard, 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 of posts, 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 by a vehicle; or

(ii)

removing or replacing elements after the road safety barrier system has been hit by a vehicle;

(c)

involve interference with the road safety barrier system, its footings, anchorages, or alter the support of the footings or anchorages during inspection or repair of the conduit or structure; and

(d)

be through part of an embankment that contains a conduit around which the surrounding ground has arched or voided.

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The information regarding the general site details and the type of vehicle that will be used for design purposes requires personal inspection by the designer. The nature of the hazard being protected is to be verified. This will allow a realistic assessment about the hazard posed to traffic should it be left unprotected. A road safety barrier system is often associated with a considerable length of installation. Whilst the severity of impacting the road safety barrier system may be less than hitting the hazard being protected, the length of 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 with the installation of a road safety barrier system. Preferred practice is to have the device located as far away from the traffic lanes as is possible. This is subject to the dynamic deflection and working width being available. However, the further away the installation is from the road, the higher is the likely angle of the impact. Accordingly, it can be inappropriate to have rigid road safety barrier systems located more than four metres from the lanes. The crash performance of rigid road safety barrier systems is often better when they 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 impacting vehicle on the system. This issue is crucial to the satisfactory performance under the design 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 the consequences of a vehicle being heavier than the design vehicle impacting the device.

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B2.3

AS/NZS 3845:1999

DESIGN AND DOCUMENTATION

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

The needs of all road users are properly taken into account.

(b)

The road safety barrier system selected is appropriate for the speed and traffic composition at the site.

(c)

The approach to the road safety barrier system means that the crashing vehicle hits at 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, where appropriate, comply with either AS 1742.3 or the appropriate guidelines published by TRANSIT New Zealand.

(g)

Specifiers evaluating their site conditions need to consider the manufacturer’s guidelines and recommendations.

For road safety barrier systems, the following criteria apply: (i)

Road safety barrier systems are considered as a unit, particularly with respect to transitions 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 is practicable. (iv)

The desirable minimum offset from a traffic lane is 500 mm, but not less than 250 mm.

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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 a road-side safety barrier system is warranted, the specific type of system is to be selected. The selection process is complex as there are many variables and some of the performance criteria are subjective.

The most desirable road safety barrier system is usually one that offers the required degree of shielding at the lowest total cost. These costs include those incurred by the agency that owns the road safety barrier system, those borne by the road users involved in the crash and the costs to those who may live in close proximity to the road safety barrier system 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 contain and redirect the nominated design vehicle.

(2)

Deflection The dynamic deflection and the working width required by the road safety barrier system should not exceed the space available.

(3)

Site conditions The slope, the condition of the terrain on the approach to the road safety barrier system and the distance from the travelled way may preclude the use of some types of installations.

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(4)

Compatibility The road safety barrier system has to be capable of being changed over to any other systems being used at the site, such as connection to a bridge railing.

(5)

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

(6)

Maintenance Non-rigid road safety barrier systems generally require more maintenance than rigid systems. Standardization of system types brings obvious advantages with respect to components storage, training of field personnel in erection and maintenance practices and the like. Simple designs often prove more effective than the complex installations.

(7)

Aesthetics The compatibility of the road safety barrier system with its surrounds can be an important selection criteria.

(8)

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

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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 safety barrier 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 plastic composites 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 factors that would reduce the effectiveness of the road safety barrier system during its design life have to be considered. Matters to be addressed include the likely changes in the performance of the road safety barrier system such as the ‘lock up’ of elements due to corrosion or due to dust. The increased potential for such problems, for example, at sites with 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 particularly adverse environmental circumstances such as marine locations or sites where snow occurs, or where there are critical elements that may undergo disabling property changes before the end of the span of life of the road safety barrier system, such as plastic elements subjected to high UV exposure or any chemical used to maintain the road safety barriers operational, such as antifreeze for water-filled plastic road safety barriers in sub-zero conditions, then these are to be clearly detailed. B2.3.4 Flooding If road safety barrier systems are to be constructed at locations that are subject to inundation at an ARI of 20 years, or lesser events, the road safety barrier system is to withstand both the hydrodynamic forces and any loads from waterborne debris. The road safety barrier system should also allow for the rapid removal of debris and for the cleaning of the road safety barrier system. For larger flood events, it is acceptable for the devices to be rendered unusable by floodwater. An inspection should be made before the road is re-opened to general traffic following any flood that could affect the system.

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B2.3.5 (a)

System details

AS/NZS 3845:1999

The following should be taken into consideration:

Impact The possible crash events at a site and the range of possible outcomes for impacts by all types of road users should be clearly identified. Traditionally, most road safety barrier systems have been tested with typical passenger cars striking the device 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 is less expensive than road safety barrier systems designed to cope with the higher loadings may be appropriate.

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(b)

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

1 in 50 years if the consequences of an accident are limited to the errant vehicle only.

(ii)

1 in 100 years otherwise.

(c)

Resolution of benefit/cost/risk analysis Early resolution of the cost benefit/risk analysis issues should be part of the specification process to ensure that the purpose of the installation is clearly understood. The ‘do nothing’ option of not installing any road safety barrier system at the site should always be considered. Preferred practice would be to install relatively inexpensive road safety barrier systems at more sites, instead of providing very expensive road safety barrier systems at few sites, provided that the trade-off in performance is acceptable.

(d)

Heavy or faster vehicles Where it is expected that the traffic mix will comprise high volumes of truck traffic or higher speeds, or both, or where the site is characterized by poor geometry, and a significant hazard exists should the road safety barrier system be penetrated by a larger vehicle, then road safety barrier systems designed to cope with the higher loadings may be appropriate.

(e)

Pedal and motorcyclists The performance of road safety barrier systems when impacted by pedalcyclists and motorcyclists is rarely verified in testing. Special measures may be necessary where the risk of impact by road users of this type is unacceptably high. At sites where a warrant for special measures for pedal and motorcyclists has been established, modifications to remove gaps that would permit a rider’s limbs to penetrate the road barrier system should be considered. The use of road safety barrier systems that present an unbroken wall should be given special weighting when comparing options at such locations. If such treatment is not justified, 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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Performance The road safety barrier system should be able to contain or redirect the design vehicle impacting at the speed and angle of impact determined for the site. At all points along the installation, the likely vertical trajectory of the impacting vehicle is to be determined, so that impact height can be determined. For most road safety barrier systems, this height will be critical. Road furniture, such as kerbs in front of a road safety barrier system should be assessed to determine whether they might influence the vehicle trajectory in such a way as to alter the likely impact height and place it outside the range of acceptable values for the road safety barrier system. Where appropriate, adjustments should be made.

(g)

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

(h)

Variation from recommended practice Where the intended use of a tested road safety barrier system varies from the manufacturer’s recommended practice, the specifier should indicate how the variance will affect the road safety barrier’s intended performance.

B2.3.6 Plan details The link between horizontal radius and road safety barrier performance can be difficult to establish. Manufacturers of road safety barrier systems have 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 small radius 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 in mountainous areas. The combination of small horizontal radius curves with crest or sag vertical curves should be carefully reviewed.

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B2.3.7 Elevation details Road safety barrier systems with relatively narrow widths of surface available for impact by a vehicle are vulnerable to vaulting or to vehicle under-ride. Consequently, the height of such road safety barrier systems becomes important 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 be plumb if the cross-fall is less than 4.5%. For steeper cross-falls, preferred practice is for the device to be perpendicular to the road surface for traffic which would travel up the cross-fall to hit the device, and vertical if traffic approaches the device down the cross-fall. At bridges and at sites where the road safety barrier system is to be erected on a structure, this practice may not be available and the details specified on the approaches should then be integrated. Regulations require that the body of a motor vehicle overhang its wheels. To minimize nuisance damage to both vehicle and the road safety barrier systems, it may be desirable to offset the face behind a road safety barrier kerb. A distance of 200-300 mm is generally required. This treatment can only be used where the speed limit is less than 70 km/h. The increased risk to pedal and motorcylists should also be considered before implementing such an offset. A roadside safety barrier is considered to be flared when it is not parallel to the edge of the travelled way. A flare is normally used to either — (a)

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change the off-set of the road safety barrier system from the travelled way (such as locations 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 in Table B1 for the relevant condition, unless testing shows that more severe rates are acceptable. TABLE

B1

FLARE RATES FOR RIGID ROAD SAFETY BARRIER SYSTEMS 85th percentile speed (km/h)

Offside distance to shy-line (m)

Nearside distance to shy-line (m)

Road safety barrier inside shy-line

Road safety barrier 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 values given in Table B2 for the relevant condition, unless testing shows that more severe rates are acceptable. TABLE

B2

FLARE RATES FOR NON-RIGID ROAD SAFETY BARRIER SYSTEMS

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85th percentile speed (km/h)

Offside distance to shy-line (m)

Nearside distance to shy-line (m)

Road safety barrier inside shy-line

Road safety barrier 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 differentiate between permanent and temporary installations. However, the hazard associated with the longer lengths of road safety barrier systems associated with a small flare rate can be effectively balanced against the risk associated with a shorter period of exposure. Under these circumstances, a flare rate as high as 5 to 1 may be adopted, provided it is for a short-term installation (a few weeks) or where the traffic volumes are very small. A risk analysis should be used to make this decision. Where pedestrian facilities are incorporated behind a road safety barrier system, the desirable minimum height of the road safety barrier system is to be approximately 1200 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 approximately 1400 mm. Separate rails may be provided to meet these requirements provided they do not have the potential to spear through an impacting vehicle, create debris that poses a serious hazard, or change the characteristics of the road safety barrier system to the extent that crash outcomes are significantly altered. COPYRIGHT

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Road safety barrier systems can be basically classified as rigid or non-rigid. Provided that sufficient width is available behind the road safety barrier system for the transverse dynamic deflection, non-rigid road safety barrier systems are preferred due to the lower accelerations experienced by the occupants of an impacting vehicle. Where space is not available to allow any dynamic deflection, then a rigid road safety barrier system is to be provided. It is then likely that the accelerations experienced by vehicle occupants will be higher when impacting such road safety barrier systems. As this increases, the possibility of injury to vehicle occupants, the necessary ‘trade offs’ need to be addressed. A check is to be made to ensure that the working width necessary is available. For determining the approach conditions, particular care should be taken to ensure that an impacting vehicle will strike the road safety barrier system at an appropriate height. The selected road safety barrier systems should indicate satisfactory performance either through crash testing or by careful assessment of the accident history of existing approved road 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 site where the road safety barrier system is to be installed are to be carefully assessed to ensure 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 be documented and the appropriate adjustments or prohibitions should be detailed. B2.3.10 Foundations on structures Where road safety barrier systems are to be erected on structures, the following are to be ensured: (a)

No damage occurs to the supporting structure due to the loading imposed during a crash.

(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 have particular 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 is necessary, to develop the full tensile strength of the road safety barrier system during impacts away from the terminal.

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The leading and trailing terminals of road safety barrier systems are not to cause an impacting vehicle to roll, vault or yaw in an inappropriate manner. The terminal is not to spear the vehicle or cause undue problems with debris. The terminal should perform acceptably when impacted from either direction, except when erected on single direction carriageways 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 road user. 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 site is effectively managed, i.e. if the maximum traffic speed is controlled, then a lower performance 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 the above functions. As tests are usually conducted in a controlled environment, the actual site conditions should be considered when selecting an end treatment. Road safety barrier systems designed prior to this requirement being specified, which can be shown to have performed well during in-service evaluation, need not be retested unless their details have been 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 to allow a vehicle to pass through when impacted at an angle to the end or at a point upstream 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 absorb part of the energy of an impacting vehicle at any point along the terminal without allowing it to pass behind the road safety barrier system.

The choice of gating or non-gating terminals is site and traffic specific, and depends upon a 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. The proprietary systems are to be installed, maintained and used as recommended by the manufacturer. Table B3 lists the up-to-date systems with the minimum installation and site requirements. TABLE

B3

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UP-TO-DATE SYSTEMS WITH MINIMUM INSTALLATION AND SITE REQUIREMENTS System name

Run-out required length × width (m)

Maximum slope adjacent to installation site

Standard length (excluding transition) (m)

Proprietary System

Slotted breakaway cable terminal (SBCT)

22.5 × 6

10:1

11.5

No

Modified eccentric loader terminal (MELT)

22.5 × 6

10:1

11.5

No

B2.3.12 Interfaces Where a road safety barrier installation is composed of different systems, e.g. with different characteristics, it is essential that the total installation act in harmony. This is of great importance where a horizontally weaker system is in advance of a horizontally stronger system, such as locations where a rigid road safety barrier system is used on a bridge and a non-rigid road safety barrier system is used on the approaches to the bridge. Where different road safety barrier systems interface, and there is a marked difference 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 barrier system is required to operate in conjunction with a road safety barrier system that has different 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 safety barrier systems and should have an appropriate transition detailing. B2.3.13 Attachments Attachments to a road safety barrier system can change its manner of operation in a crash. This is particularly the case where rails, and similar elements 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 struck during crashes with high vehicles. This is particularly the case where non-rigid road safety barrier 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 associated with passenger cars, it is likely that elements, such as the bonnet, can penetrate through gaps left in the face of a road safety barrier system. This can cause unacceptable ride down acceleration and yawing as the components of the vehicle hit vertical members. It can 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 been crash tested. Where there is a high risk that the crash may involve a pedal cyclist or a motorcyclist, the road safety barrier installation should be reviewed to see whether a system can be used which does not allow penetration by riders’ limbs. If this is not possible, 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 a complex sequence of dynamic events. It is very difficult to derive the actual loads to be resisted. From the perspective of road safety barrier strength and vehicle containment, the primary collision is believed to be the most important factor. If the vehicle can be redirected parallel to the road safety barrier system, it will be contained on the traffic side of the road safety barrier system in almost every case. Accident data that shows penetration of a road safety barrier system during a second collision is not available. The impact loading severity can be inferred by a quasi-energy equation E = 1/2 mv2sin θ 2. Assigning a vectorial sense to energy, which is a scalar quantity, is technically meaningless. However, for uniformly loaded vehicles, it can be shown that there is a relationship between energy and maximum road safety barrier deflection during the primary collision. The redirection index estimates the horizontal impulse on a longitudinal road safety barrier system during a vehicle collision from the incident of impact until the vehicle becomes parallel with the road safety barrier system, or loses contact with the road safety barrier system.

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B2.4.1

General

It is expected that —

(a)

the road safety barrier system erected and the materials used are in accordance with the specification;

(b)

advice would be obtained about particular site problems that may arise. Issues would include curved installations, sites where specified post depths are not practicable, and site conditions that are different to those envisaged;

(c)

documentation of the product is provided, adequate enough to ensure that the installation can be performed satisfactorily;

(d)

installers follow the documentation provided for installing the road safety barrier accordance with the specification. The method of erection should not damage mark the appearance of the road safety barrier system or other road components the vicinity of the installation or create unnecessary hazards for road users such sharp edges and protruding bolts;

(e)

where the properties of critical components are expected to change over time, the appropriate procedures to allow determination of the remaining life of such components are to be specified;

(f)

guarantees will be provided as to the availability of replacement components, or acceptable equivalents, within a reasonable time;

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a process is to be used that will not damage or distort components, so that they cannot function in the manner intended or significantly reduce the span of life of the road safety barrier system; a method of erection is to be adopted that does not damage or mark the appearance of the road safety barrier system or other road components that are in the vicinity of the installation, or create unnecessary hazards for road users, such as sharp edges and protruding bolts;

(i)

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

(j)

resources are available to obtain advice about particular site problems that may arise. Issues would include curved installations, sites where specified post depths are not practicable and where site conditions are different to those envisaged.

B2.4.2 Damage and B2.4.3 Component identification and assembly details Incorrect assembly of a road safety barrier system can introduce profound changes into its manner of operation. Incorrect assembly can be caused through damage to critical components which do not allow the correct assembly to occur. Confusion regarding the correct orientation of elements, or even substitution of elements into incorrect positions can cause problems. It is expected that road safety barrier systems are assembled by those familiar with the process. It is also a requirement that such people are aware of the methods of coping with the variations that can occur in site conditions. However, details of the appropriate assembly process should be provided by manufacturers. Texts that provide a check-list to ensure that critical elements are properly assembled are also required. B2.4.4 General tolerances The particular perspective that motorists have of a road safety barrier system makes a smooth, even alignment an important necessity to be achieved. B2.4.5 Surface finish A smooth surface of the road safety barrier system reduces the possibility of a vehicle yawing on impact. It also promotes a vehicle sliding along the road safety barrier system, which ensures that ride down accelerations are kept as low as is practical. A smooth surface also reduces the risk of fire. The surface finish should hard so that it does not show incidental damage. Surface treatments may be coloured but these should not accentuate any problems of incidental damage.

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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 barrier system, that are likely to snag people are to be avoided. B2.4.6 Setting out The proposed installation should be carefully assessed to ensure that its location is optimal. The area behind any road safety barrier system that ‘gates’ is to be carefully reviewed. B2.4.7 Sequence of work Where possible, a road safety barrier system is to be erected so that the leading terminal is completed at the earliest possible moment and the rest of the 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 be specified. B2.4.8 Installation acceptance criteria for posts Driving posts is an acceptable practice, provided that it does not cause distortion or damage to the posts such that it reduces either the effectiveness of the road safety barrier system, or its span of life. Site repairs 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 that this is practically impossible, the matter is to be documented. Cutting the ends off posts may be permissible to one or two adjoining posts, provided that the integrity of the road safety barrier system is not reduced by such a practice. B2.4.9 Construction acceptance criteria for foundations The foundations of the road safety barrier system are a critical element which ensures that the road safety barrier system performs as tested. It is expected that manufacturers, designers and erectors review the foundation conditions to ensure that the intended outcomes will be achieved in case of a crash. For non-rigid road safety barrier systems, the provisions of additional anchors may be used at sites where the necessary levels of support are not available. Using rails of heavier thickness, either a thicker gauge or ‘nesting’ of elements can be used. Details of appropriate crash-tested solutions are available. For non-rigid road safety barrier systems in the public domain using posts, the following conditions should be met: (a)

The steel posts should be able to move, i.e. they should not be surrounded by concrete or similar material that restricts flexibility.

(b)

Failure mode of the steel post is to be plastic yielding at a depth not less than 75 mm below ground level.

(c)

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

B2.4.10 Construction acceptance criteria for concrete The criteria given in Clause 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 can catch fire. In a crash, there is a risk that the vehicle will catch fire. Accordingly, the materials of the road safety barrier system are not to act as a fire accelerant to the situation. The opportunities for vandals to damage the road safety barrier system is also to be addressed. Any surface coating on the road safety barrier system should not be capable of being 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 are essential given the various applications that occur.

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Attention is to be paid to the speed zone to ensure that the road safety barrier system will not 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 range of applications and periods of use on site, plastic road safety barrier systems require frequent inspection. The documentation supplied by the manufacturer should include the methods for the disposal of discarded plastic road safety barrier sections. B2.4.12 Construction acceptance criteria for steel components Design elements are to be correctly assembled. Particular care is to be taken with the overlap or orientation, or both, 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 total area that is allowed to be repaired. Particular care is to be taken with stacking of components 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 safety system, care should be taken to ensure that the needs of particular road user groups have been 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 monitor the road safety barrier systems;

(b)

road safety barrier systems are regularly inspected in accordance with a program of surveillance;

(c)

critical elements can be readily accessed and replacement of elements that have reached the end of their span of life is to be available; and

(d)

feedback about issues relating to service performance, which may prove critical at similar installation, should be provided.

A program should be established for the inspection of non-rigid road safety barrier system installation. The program should encompass the following: (i)

Stage 1 ‘Drive-by’ inspection to identify the need for repairs after impact and whether sufficient ballast is present in the case of ballasted road safety barrier systems.

(ii)

Stage 2 ‘Walk-by-and-stop’ inspection to identify the need for repairs due to vandalism, weathering, scour, changes to the adjoining ground and pavement surface, 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 of delineating devices, unauthorized changes made to the road safety barrier layout, changes to any poles, roadside vegetation and whether sufficient ballast is present in the case of ballasted road safety barrier systems.

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(iii) Stage 3 The criteria of Stage 2 applies to Stage 3, however, any specific technical requirement regarding that type of road safety barrier system are to be taken into consideration. (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 barrier system at that location, and considering the specific technical requirements regarding that type of road safety barrier system.

(v)

Stage 5 Detailed examination of the results of the inspections undertaken across the non-rigid road safety barrier installation. Stage 5 should determine whether there is a need to alter any of the procedures associated with the non-rigid road safety barrier systems, including those for inspecting the non-rigid road safety barrier systems.

Procedures should be established for each stage of inspection, and should involve the following: (A)

Pre-site inspection preparation, including the review of the findings of previous inspections at that site, recommendations made as a result of those inspections, and any other measures undertaken at that installation since the last inspection.

(B)

Site inspection, including the actual inspection, digital and graphical recording of findings, 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. COPYRIGHT

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(C)

Specification of flow-on action, resulting from reflection on the site inspection findings, 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 action plans as specified in Clause 2.6.1 should be implemented and that records be kept as evidence of that implementation. This plan will include procedures to identify and restore components damaged in crashes, natural events or by vandalism. It is not expected that repairs will be undertaken immediately; however, the site should not remain in a hazardous or unsafe condition. Even extraordinary repairs may be deferred depending on the site, resources and other matters. The following are to be determined after a crash: 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 barrier system.

(d)

Should the type of road safety barrier system be changed.

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(a)

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C

COMMENTARY ON SECTION 3 (Informative) C3.1 SCOPE All road safety barrier systems can be viewed as rigid during low energy impacts. However, Section 3 specifies those road safety barrier systems that are designed so that there is no dynamic deflection during an impact by the design vehicle travelling at the test level speed and angle of impact. C3.2 GENERAL Rigid road safety barrier systems are often used along the edge of road structures, such as bridges, retaining walls and the like. However, the installation of a rigid road safety barrier system is no guarantee that containment of an impacting vehicle will occur. Under the test conditions specified in this Standard, a rigid road safety barrier system is required to meet specified outcomes. Included in these outcomes are requirements regarding the accelerations and velocity of impact experienced by vehicle occupants during a crash. Non-rigid road safety barrier systems generally have better outcomes than rigid road safety barrier systems. However, a rigid road safety barrier system may be the only option at some locations. These include sites where there are features behind the road safety barrier systems, such as a pedestrian footpath and public utility duct, which dictate that the road safety barrier should not be permitted to move. Properly designed rigid road safety barrier systems give better results when impacted at lower angles than the test values. This is generally achieved by placing the road safety barrier system in close proximity to traffic lanes. However, on multi-lane bridges, it is possible that even this measure will not reduce the impact angles in some crashes. Placing road safety barrier systems a long distance from the carriageway, increases the impact angles, but reduces impact speed.

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C3.3 DEVELOPMENT OF DESIGN For all road safety barrier systems, the need to consider the outcomes when the road safety barrier is impacted by vehicles that have higher levels of kinetic energy is necessary. Particular attention should be paid to the location of the centre of gravity as some of these higher kinetic energy situations will involve vehicles of larger mass and higher centres of gravity. The issue of working width should be considered at sites where rigid road safety barrier systems could be impacted by high vehicles. Crash tests show that such vehicles can roll over the top of the road safety barrier system unless it is high enough to restrain such movement. This means that tall elements behind a rigid road safety barrier system may be impacted by the upper parts of such vehicles. The need for a compromise between limiting horizontal deflection whilst controlling the in-vehicle accelerations during the process of absorbing the energy of the impacting vehicle is a trade off that should be made consciously. Rigid road safety barrier systems can have higher ride down accelerations. Accordingly, the risk for personal injury to occupants in the vehicle will be increased with such devices. In the development of the design, the hazard associated with portions of a vehicle load coming off during an impact should be considered. As well, the loss of vehicle components, such as vehicle hubcaps, may pose an unacceptable risk at some sites. C3.4 ANALYSIS OF STRESSES IN RIGID BARRIERS Longitudinal road safety barrier systems should be designed and constructed to restrain the idealized design vehicle, 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. The intensity of longitudinal load should be calculated as a product of the coefficient of friction (µ) and the horizontal load. The coefficient of friction (µ) should not be less than 0.4 for concrete type F barrier. It may vary for other shapes. The value of the longitudinal length of the distributed impact force (lt) should be as given in Table C1 for the appropriate type of vehicle, unless a crash test of a vehicle proves otherwise. Sufficient reinforcement should be provided to a concrete road safety barrier system to have the required flexural capacity along the v-shaped yield line. The critical length of the yield 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 the following 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 to Mw 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 the following equation: R

Mb lc −

(ii)

lt 2

lc −

lt 2

2

M c lc

lt

h i(l c −

2

. . . C1(3) )

For impacts within the road safety barrier segment, from the following equation: R

8M b lc −

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Mw hi

lt 2

8M w h i lc −

lt 2

2

M c lc h i(l c −

lt 2

. . . C1(4) )

Road safety barrier systems that rely on continuous support from the foundation generate some efficiencies due to the length available to dissipate the impact stresses. Post systems tend to concentrate the loading. Details of the connection between the road safety barrier system and the structure should be designed with a ‘fuse’ arrangement that facilitates repair and ensures that stresses in the supporting structure are not exceeded. Where this supporting structure is a bridge, it should be noted that there are practical limits in the capacity 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 appropriate test level.

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The stiffness of the bodies of trucks means that the crash outcomes with such vehicles is likely to be substantially different to that of passenger cars. The impact from a rigid single unit vehicle is often more severe than the impact from an articulated vehicle of the same mass. The longer impact periods associated with an articulated vehicle are of real benefit. Designers should note that there are some practical difficulties associated with containing vehicles having a high centre of gravity. Above a height of approximately 1200 mm from the 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 transverse restraints at levels above 1200 mm. Even road safety barrier systems with a solid face may cause considerable structural damage to vehicles at heights above the tray. TABLE

C1

LONGITUDINAL LENGTH (lt) Longitudinal length (lt) (mm)

Type of vehicle 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 Design load (kN)

Minimum height above road surface (mm)

Test level 2

100

535

Test level 3

100

535

Test level 4

300

820

Test level 5 <

700

1 500

Category

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

C3.7 FOUNDATIONS The loading that is to be absorbed by the support structure should also be considered with the design of a rigid road safety barrier system. It is important to ensure that the support structure remains intact during the design impact. An assessment is also to be made about the consequence to the support structure when the actual 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 the design 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 DOMAIN Where the speed limit on the road is 80 km/h or higher, preferred practice is to locate pedestrian 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

STRESSES IN RIGID ROAD SAFETY BARRIER SYSTEM

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FIGURE C1

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ARRANGEMENT OF FOOTWAY AND PEDAL CYCLE FACILITIES

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FIGURE C2

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D

COMMENTARY ON SECTION 4 (Informative) D4.1 SCOPE Unprotected road users to motorcyclists, pedal cyclists and pedestrians.

be

taken

into

consideration

include

At many sites the following possible events should be considered: (a)

Glancing impacts which may cause significant damage to the road safety barrier system.

(b)

The impacting vehicle or unprotected road user may snag on the road safety barrier system.

(c)

The non-rigid road safety barrier may deflect so far as to cause the impacting vehicle to hit an object or facility located in the roadside or abutting property. The consequences 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. The consequences may be that the vehicle penetrates into abutting property and causes injury to the occupants of that property, for example, children in kindergarten playgrounds.

(e)

On narrow medians, a non-rigid road safety barrier may deflect on impact to the extent that oncoming traffic is caused to swerve or brake suddenly, which may lead to 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. Such congestion could create the risk of additional traffic accidents and place staff repairing the road safety barrier system at risk. At such sites, special attention would need to be given to 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 repair after impact. D4.3 INSTALLATION Clause 4.2 specifies that the features of each site will influence markedly what type of non-rigid road safety barrier system should be used at that site and what should be the road safety barrier layout. This means that if the site features change, then the type of road safety barrier system or its layout, or both, may no longer be appropriate.

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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 need to minimize the potential for unprotected people to be struck by failing wire ropes. Up to now the longitudinal components of metal non-rigid road safety barrier systems have been either beams or wire ropes. Thus there seems not to have been any road safety barrier systems whose longitudinal components are both beams and tensioned wire ropes. However, some non-rigid road safety barrier systems under development will comprise beams 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’ and instead to ‘road safety barriers embodying tensioned wire ropes’. The steel cable in the breakaway cable terminal is under very little tension, so there is no possibility 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 barriers embodying tensioned wire ropes’. COPYRIGHT

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D4.4.2.1 Intended function Already there are a few road safety barrier systems that perform as rigid road safety barriers when hit by cars, but perform as non-rigid road safety barriers when hit by heavy commercial vehicles. In the future it is possible that road safety barrier systems will be developed with several redirective stages. With these road safety barrier systems, the Stage 1 behaviour will mean that the road safety barrier systems perform as non-rigid road safety barrier systems when hit by cars and the Stage 2 behaviour will mean that the same road safety barrier system behaves as a non-rigid road safety barrier system when hit by heavy commercial vehicles. D4.4.2.2 Practical usefulness It is acknowledged that it may be practically impossible for developers of non-rigid road safety barrier systems to design systems to cater for the full range of situations likely to be encountered on site. However, it is important that developers recognize that to be operational, road safety barrier systems should be site friendly. Figure D1 shows some situations into which the road safety barrier systems are often required to fit. Clauses 4.2 and 4.3 specify that specialized information is required for making decisions regarding non-rigid road safety barrier installations. It is recognized that until a road safety barrier system has been in service for some time, some of this specialized information may be unavailable. D4.4.3.2 Rope tension, anchorage and tension devices The design of anchorages and tension devices, their spacing along the length of the road safety barrier system and the procedures associated with the road safety barrier system should be such as to —

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(a)

enable the required tension to be developed in all of the ropes along the full length of the road safety barrier system with special consideration being given to the following: (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 is possible, for example, that where a wire rope changes direction at a post, the friction between the rope and the post may be so large as to cause a tension drop at that point. This in turn can mean that along the length of the rope these tension drops can form a ‘tension profile’ and that the tension ‘loss’ becomes so large as to impair the effective performance of the road safety barrier 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 is released whilst leaving the other tensioning devices fully tensioned. If the tension in a wire rope is suddenly released, the rope may fly sideways very violently so as to injure or kill a pedal cyclist, a motorcyclist or an unprotected person nearby. It could be argued that the authorities responsible for working with the road safety barrier systems would be aware of the risks involved with this type of road safety barrier system. However, in an emergency or through vandalism, a lay-person could undo a rope tensioning device and this action could have tragic consequences if this de-tensioning causes the sudden release of the tension; and

(c)

ensure that all of the components of the road safety barrier system remain in their correct location relative to each other. Normally, this will involve examining and planning the behaviour of the road safety barrier system under the following conditions: (i)

When the road safety barrier system is at rest.

(ii)

Under any unexpected temperature or climatic conditions.

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During vehicular impact.

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

(d)

avoid any potential for entrapment of limbs by tensioning devices along the length of need.

D4.4.3.3 Rope diameter The requirement of 19 mm min. diameter is to prevent the use of smaller diameters which might increase the risk of injury to an unprotected road user who hits the ropes. Also, the 19 mm minimum diameter ensures that the ropes have a tensile strength sufficient to prevent fracture of the ropes during impact. D4.5.1 General The types of public domain road safety barrier systems given in Table 4.5.1 are the only ones that are permitted. This is because at the time of preparing this Standard, they are the only public domain road safety barrier systems for which there are public domain crash-safe terminals and structure transitions. D4.5.2 Area between traffic lane and road safety barrier system Vehicles may overturn following impact with the non-rigid road safety barrier system if the ground between the traffic lane and the road safety barrier system is uneven or contains a depression 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 road safety barrier system;

(b)

the area between the traffic lane and the road safety barrier system has a cross-fall greater than 1 on 10; or

(c)

both.

D4.5.3 Location and orientation of steel blockouts, posts and nailing laps This will involve examining the potential roadside encroachment frequencies of adjacent traffic lanes. D4.5.4 Post foundations on natural ground The satisfactory performance of these non-rigid road safety barrier systems requires that if the road safety barrier system is hit by the range of vehicles, the posts remain in place to develop a substantial part of their bending strength and the soil behind the posts then yields enabling the posts to yield approximately 75 mm below the ground. If the soil surrounding the posts is too weak, the posts will plough through the ground too soon, so that the road safety barrier system may deflect too far and perhaps cause the impacting vehicle to vault the road safety barrier system.

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Post footings are generally satisfactory if — (a)

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

(b)

the posts are not mounted rigidly on concrete footings such as slab, beams or concrete 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-lift asphaltic concrete.

When backfilling around posts, it should be remembered that failure to rod the material can 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 be rectified by water-jetting the backfill around the posts. However, if water-jetting is performed, care should be taken to ensure that the water-jetting does not damage the parent material surrounding the hole. COPYRIGHT

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In some locations, the material close to the ground surface is not so hard as to support the posts too rigidly, yet below the ground there is very stiff clay or small boulders such that when the posts are driven into the ground, the head of the post is damaged by the driving hammer. Sometimes, such damage can be prevented by using a heavier hammer or using a driving 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-rigid public domain road safety barrier systems can cause the W-beams or thrie-beams to deflect too far between the posts, which can in turn cause the impacting vehicle to snag on the posts.

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D4.5.6 Fixing of the W-beam or thrie-beam to the blockouts It is important that washers be installed only where shown in the figures of Appendix F. This is because in an impact, the W-beam or thrie beam should be able to pull free of the posts and thereby remain at the correct height. If the W-beam or thrie-beam does not pull free and instead is dragged down with the posts, the impacting vehicle will tend to vault the road safety barrier system or snag on the posts.

FIGURE D1 (in part)

SITUATIONS INTO WHICH NON-RIGID ROAD SAFETY BARRIERS MAY HAVE TO FIT

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SITUATIONS INTO WHICH NON-RIGID ROAD SAFETY BARRIERS MAY HAVE TO FIT

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FIGURE D1 (in part)

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E

COMMENTARY ON SECTION 5 (Informative) For commentary on Section 5, see NCHRP Report 350.

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

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F

DETAILS OF A ROAD SAFETY BARRIER LAYOUT (Normative)

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This Appendix provides the following details of a road safety barrier system deemed to comply 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 the road 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. DIMENSIONS IN MILLIMETRES

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. DIMENSIONS IN MILLIMETRES

FIGURE F3 THRIE-BEAM ASSEMBLY—STANDARDS BLOCKOUTS COPYRIGHT

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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. DIMENSIONS IN MILLIMETRES

FIGURE F4 MODIFIED THRIE-BEAM ASSEMBLY—NOTCHED BLOCKOUTS COPYRIGHT

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

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DIMENSIONS IN MILLIMETRES

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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DIMENSIONS IN MILLIMETRES

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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DIMENSIONS IN MILLIMETRES

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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DIMENSIONS IN MILLIMETRES

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. DIMENSIONS IN MILLIMETRES

FIGURE F10 GENERAL ARRANGEMENT TRAILING TERMINAL

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FIGURE F11 GENERAL ARRANGEMENT MODIFIED ECCENTRIC LOADER TERMINAL (MELT) COPYRIGHT

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FIGURE F12

W-BEAM

SPECIFICATIONS Corrugated W-beam elements shall be formed from steel grade HA350 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 with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE This corrugated W-beam shall be used as a rail element in standard barrier 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 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 with AS 1650. The minimum coating mass shall be 900 g/m 2,total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices.

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INTENDED USE These corrugated steel beams shall be used as rail elements in the standard 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 grade HA350 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 with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Corrugated thrie-beams shall be used as a rail element in standard barrier 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. COPYRIGHT

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FIGURE F15

W-THRIE TRANSITION SECTION

SPECIFICATIONS W-thrie transition section elements shall be formed from steel grade HA350 or equivalent in accordance with AS/NZS 1594. Beams shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE W-thrie transition sections shall be used as the transition section between the W-beam and thrie-beam barrier types.

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NOTE: For further information, see Figure F5.

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FIGURE F16

C-POST — W-BEAM, TRANSITION BEAM

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SPECIFICATIONS W-beam posts shall be formed from steel grade HA300 in accordance with AS/NZS 1594. Posts shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE W-beam posts shall be used with W-beam and transition beams in standard 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 in accordance with AS/NZS 1594. Posts shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9.

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Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Thrie-beam posts shall be used with thrie-beams in standard barrier types G9, G9 modified, MB9 modified and structure transitions.

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FIGURE F18

SPECIFICATIONS with AS/NZS 1594.

C-POST — END POST

End posts shall be formed from steel grade HA300 in accordance

Posts shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides.

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Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. 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. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices.

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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 for details).

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FIGURE F20

TIMBER POST FOR NEW ZEALAND ONLY

SPECIFICATIONS Timber posts shall be produced from run of the mill pinus radiata preservative treated to hazard level H4 in accordance with AS 1604. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. Timber posts shall be used in the standard guardrail panels.

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INTENDED USE

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FIGURE F21

BLOCKOUT — W-BEAM

SPECIFICATIONS W-beam blockout blocks shall be formed from steel grade HU300 in accordance with AS/NZS 1594.

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Blocks shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE and MB4.

W-beam blockout blocks shall be used in standard barrier designs G4

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FIGURE F22

BLOCKOUT — THRIE-BEAM

SPECIFICATIONS Thrie-beam blockout blocks shall be formed from steel grade HU300 in accordance with AS/NZS 1594. Blocks shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Thrie-beam blockout blocks shall be used in standard barrier designs G9 and structure transitions. COPYRIGHT

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FIGURE F23

MODIFIED BLOCK — THRIE-BEAM

SPECIFICATIONS Modified thrie-beam blocks shall be formed from steel grade HU300 in accordance with AS/NZS 1594.

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Blocks shall be treated and hot dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Modified thrie-beam blocks shall used in the standard barrier designs G9 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 grade HU300 in accordance with AS/NZS 1594. Blocks shall be treated and hot dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Block-out transition blocks shall be used in the standard structure transition design shown in Figure F2.

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FIGURE F25 (in part)

BUFFERED END SECTION AND DIAPHRAGM COPYRIGHT

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FIGURE F25 (in part)

BUFFERED END SECTION AND DIAPHRAGM COPYRIGHT

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SPECIFICATIONS Buffered terminal sections and diaphragms shall be formed from steel grade HA350 or equivalent in accordance with AS/NZS 1594. Sections and diaphragms shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Terminal sections shall be used in the standard MELT and trailing terminal designs as shown in Figures F3 and F4.

Accessed by GHD PTY LTD on 05 Mar 2012

NOTE: Diaphragms are not required in a trailing terminal.

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DIMENSIONS IN MILLIMETRES

FIGURE F26

STRUCTURE CONNECTOR — W-BEAM

SPECIFICATIONS Corrugated W-beam structure connectors shall be formed from steel grade HA350 or equivalent in accordance with AS 1595. Connectors shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices.

Accessed by GHD PTY LTD on 05 Mar 2012

INTENDED USE W-beam structure connectors shall be used in some of the rail element terminal configurations employed with the standard W-beam barrier type G4 and MB4 designs.

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DIMENSIONS IN MILLIMETRES

FIGURE F27

STRUCTURE CONNECTOR — THRIE-BEAM

SPECIFICATIONS Corrugated thrie-beam structure connectors shall be formed from steel grade HA350 or equivalent in accordance with AS/NZS 1594. Connectors shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9.

Accessed by GHD PTY LTD on 05 Mar 2012

Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Thrie-beam structure connectors shall be used in some of the rail element 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. DIMENSIONS IN MILLIMETRES

FIGURE F28

CAST-IN ANCHOR ASSEMBLY FOR THRIE-BEAM

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DIMENSIONS IN MILLIMETRES

FIGURE F29

ANCHOR BRACKET

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SPECIFICATIONS Anchor brackets shall be formed from steel grade HA250 in accordance with AS/NZS 1594. Anchor brackets shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. INTENDED USE Anchor brackets shall be used to anchor the cable assembly (see Figure F25) to the end rail in the standard MELT and trailing terminal design as shown in Figure F3.

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NOTES: 1

Dimensions are subject to manufacturer’s tolerances except where permissible tolerances are nominated.

2

All timber posts shall be grade F8 Australian slash pine preservative treated to hazard level H4 (H5 in extreme wet conditions) in accordance with AS 1604.

3

Timber posts shall be milled square. All longitudinal edges shall be chamfered 5 × 5. DIMENSIONS IN MILLIMETRES

FIGURE F30

STEEL TUBE AND SOIL PLATE

SPECIFICATIONS Steel tubes and soil plates shall be fabricated from steel grade 250 in accordance with AS/NZS 1594. Tubes and plates shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides.

Accessed by GHD PTY LTD on 05 Mar 2012

Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9. INTENDED USE Steel tubes and soil plates shall be used in the standard MELT terminal. Soil plates only shall be used in the standard trailing terminal.

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DIMENSIONS IN MILLIMETRES

FIGURE F31

SPECIFICATIONS with AS/NZS 1594.

SHELF ANGLE

Shelf angles shall be formed from grade 250 steel in accordance

Shelf angles shall be hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. Shelf angles shall be used in the standard MELT terminal.

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INTENDED USE

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NOTES: 1

Dimensions are subject to manufacturer’s tolerances except where permissible tolerances are nominated.

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 thick galvanized steel washers.

4

Hexagon nuts shall be in accordance with AS/NZS 1112 (grade 5). Nuts shall be tapped to suit galvanized thread. Black steel washers, large series in accordance with AS 1237 and shall be hot-dip galvanized in accordance with AS 1214.

5

All nuts shall be snug tight in accordance with AS 4100. DIMENSIONS IN MILLIMETRES

FIGURE F32

STRUT AND YOKE ASSEMBLY

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SPECIFICATIONS with AS 1163.

118

Struts shall be RHS steel grade 350 or equivalent in accordance

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 with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Dimensional tolerances not shown or implied shall be consistent with the proper functioning of this part, involving its appearance and accepted manufacturing practices. Strut and yoke assemblies shall be used in the standard MELT

Accessed by GHD PTY LTD on 05 Mar 2012

INTENDED USE terminal.

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NOTES: 1

Dimensions are subject to manufacturer’s tolerances except where permissible tolerances are nominated.

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 thick galvanized steel washers.

4

Hexagon nuts shall be in accordance with AS/NZS 1112 (grade 5). Nuts shall be tapped to suit galvanized thread. Black steel washers, large series in accordance with AS 1237 and shall be hot-dip galvanized in accordance with AS 1214.

5

All nuts shall be snug tight in accordance with AS 4100. DIMENSIONS IN MILLIMETRES

FIGURE F33

CABLE ASSEMBLY

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SPECIFICATIONS Cable shall be minimum 20 mm in diameter, 6 × 19 or 6 × 24 wire strand 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 of 200 kN and hot-dip galvanized in accordance with AS 1650. Galvanized nuts shall be in accordance with AS/NZS 1112. INTENDED USE terminal design.

Cable assemblies shall be used in the standard MELT and trailing

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DIMENSIONS IN MILLIMETRES

FIGURE F34

PIPE SLEEVE

SPECIFICATIONS Pipe sleeves shall be manufactured from standard galvanized pipe in accordance with AS 1163.

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INTENDED USE Pipe sleeves shall be used in anchoring the cable assembly in the standard MELT terminal.

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DIMENSIONS IN MILLIMETRES

FIGURE F35

BEARING PLATE

SPECIFICATIONS Bearing plates shall be manufactured from steel grade HA250 in accordance with AS/NZS 3678. Plates shall be treated and hot-dip galvanized after fabrication in accordance with AS 1650. The minimum coating mass shall be 900 g/m 2, total both sides. Renovation of damaged or uncoated areas shall be in accordance with AS 1650. Zinc-rich paints shall be in accordance with AS/NZS 3750.9.

Accessed by GHD PTY LTD on 05 Mar 2012

INTENDED USE Bearing plates shall be used for anchoring the cable assembly to the post in the standard MELT and trailing terminals.

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DIMENSIONS IN MILLIMETRES

FIGURE F36

M16 MUSHROOM HEAD BOLT AND NUT

SPECIFICATIONS Mushroom head splice bolts and oversize nuts (M16 × 30) shall be of 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.

Accessed by GHD PTY LTD on 05 Mar 2012

The length of thread on mushroom headed bolts shall be such that the nut touches the oval 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 MELT terminal.

M16 × 50 mm bolts shall be used for fastening rails to steel C-posts and blocks in the standard barrier designs G4, G9, G9 modified, MB4, MB9 modified, trailing terminals and structure transitions. COPYRIGHT

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DIMENSIONS IN MILLIMETRES

FIGURE F37

SPECIFICATIONS AS/NZS 1111.

Bolts

shall

M16 HEX HEAD BOLT AND NUT

be

of

property

class 4.6

in

accordance

with

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-beam rail 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.

Accessed by GHD PTY LTD on 05 Mar 2012

NOTE: See Figure F31 for washers that may be used with these bolts.

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DIMENSIONS IN MILLIMETRES

FIGURE F38

SPECIFICATIONS AS/NZS 1111.

Bolts

shall

M20 HEX HEAD BOLT AND NUT

be

of

property

class 4.6

in

accordance

with

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 the steel 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 the standard MELT terminal. M20 × 300 bolts and nuts shall be used to fasten the yoke assembly to the steel tubes in the standard MELT terminal.

Accessed by GHD PTY LTD on 05 Mar 2012

NOTE: See Figure F31 for washers that may be used with these bolts.

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DIMENSIONS IN MILLIMETRES

FIGURE F39

RECTANGULAR PLATE AND ROUND WASHER

SPECIFICATIONS Washers shall be made of steel and shall be hot-dip galvanized in accordance with AS 1650. INTENDED USE Rectangular plate washers shall be used with the post bolt at the leading and trailing posts in the standard MELT and trailing terminals.

Accessed by GHD PTY LTD on 05 Mar 2012

M20 round washers shall be used with the bolts fastening the soil plate and yoke assembly in the standard MELT.

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