road design note 06-16 - barrier design commentary (v1.0)

RDN 06-16 Version 1.0 August 2021 of 2

Abstract This document provides commentary on the safety barrier design process, including product specific notes, design philosophies and common practices.

Key Information This document is administered by Engineering, Department of Transport on behalf of Head, Transport for Victoria. This document must be read in conjunction with the DoT Supplement to AGRD Part 6.

Where information contained in this document cannot be followed, the designer, engineer or team may seek technical advice (from the Department of Transport or delegated Technical Advisor) and gain acceptance (if necessary) for a departure from this guideline.

1. Purpose This Road Design Note (RDN) provides commentary on the ‘DoT Supplement to Austroads Guide to Road Design (AGRD): Part 6 – Roadside Design, Safety and Barriers’, including product specific notes and additional context.

1.1 Consolidation of barrier design documents RDN 06-02, RDN 06-08 and RDN 06-15 were all developed to supplement the guidance in AGRD Part 6 with specific information on Wire Rope Safety Barriers, Steel Beam Guard Fence and the application of continuous safety barrier.

While each of these documents provided a comprehensive standalone document, they all contained significant overlap with each other and the Supplement to AGRD Part 6. As such, these RDNs have been reviewed, any duplicated information has been identified and the relevant guidance has been consolidated and incorporated into the Supplement and this commentary. As a result, RDN 06-02, 06-08 and 06-15 will be withdrawn.

1.2 Current barrier design documents To clarify the current relationship between safety barrier design documents, the following structure has been provided in Figure 1.

AGRD Part 6 and the DoT Supplement to AGRD Part 6 are the primary references for barrier design and design values. The Supplement will reference relevant material such as the Road Design Notes, Guideline Drawings and Accepted Products. These documents set the desirable design values for barrier design and the process to use when departing from these values.

RDN 06-16 supports the requirements in AGRD Part 6 and provides specific information on the various product types.

Guideline Drawings also support the requirements in AGRD Part 6 by providing a visual representation of certain barrier design concepts. Verification is required that the concepts are applicable to contexts being addressed when developing site specific solutions.

Barrier design commentary Road Design Note

RDN 06-16 August 2021

Technical Guideline

Figure 1 - Barrier Design Documents

AGRD Part 6

DoT Supplement to AGRD Part 6

RDN 06-16 -Barrier Design Commentary

Guideline Drawings

RDN 06-04 -Accepted Safety Barrier Products

Austroads TCU's

DoT Detail Sheets

Standard Drawings


RDN 06-04 provides a list of road safety devices that DoT has assessed and considers acceptable for use on the declared road network, subject to appropriate design and installation. This RDN contains general conditions of use relating to safety barriers, current safety barrier policies, and it also references the relevant Technical Conditions of Use for each product.

Austroads Technical Conditions of Use (TCUs) are the Austroads reference for product specific performance and design. These documents have been adopted directly by DoT to improve national harmonisation and are referenced throughout RDN 06-04 – Accepted safety barrier products.

DoT Detail Sheets are only provided in special circumstances, where DoT accepts a safety barrier product that has not been assessed by Austroads or where DoT has specific conditions or variants that cannot be contained within RDN 06-04.

Standard Drawings provide specific safety barrier details for construction, including the manufacture and installation details for several public domain systems

For barrier installation documents, refer to Section 4.0.

2. AGRD Part 6 – Section 5 – Barrier Design The following section is formatted to match Section 5 of the AGRD Part 6 (2020) and the DoT Supplement (2021). Sections with ‘no commentary’ have been omitted.

5.3.4 Determine the Lateral Position of the Barrier (Step B3)

Lateral position of barrier on an embankment When a vehicle passes over a sloped batter or kerb, it may follow a trajectory that influences the interaction (i.e. engagement) between the vehicle and the safety barrier. Should it be necessary to place a barrier on the embankment slope, it must be placed a suitable distance behind the kerb or beyond the hinge point to mitigate these effects.

AGRD Part 6 Commentary 6 details this concept, and it aligns closely with the AASHTO 2012 recommendation to provide a barrier free area from hinge point to 3.6m beyond the hinge point on a 6:1 slope.

Lateral position of Guard Fence on an embankment

Within previous DoT guidelines, it was recommended that on a 6:1 or flatter slope, guard fence should be located as close as possible to the hazard and to create a 10:1 sloped area at least 2m wide immediately in front of the GF. While this is still considered good practice, the lateral distance from the hinge point to barrier is significantly more critical, and should be the focal point, therefore the requirement to have a 2m wide area in front of GF has been withdrawn.

Lateral position of Wire rope safety barrier on an embankment DoT is only aware of one WRSB product (SlopeFence) that was designed and tested on a batter slope steeper than 6:1. The product had a wider cable spread to ensure containment of high and low angle vehicle departures. While this product was trialled in Victoria, it did not have significant whole-of-life advantages and is therefore no longer accepted for use.

5.3.5 Offset to traffic lane

Barrier setback from kerb

Historical barrier-kerb setback guidance. The following information on barrier-kerb interaction has been provided for reference only. Following a thorough review of available literature (Troutbeck 2020), DoT has modified Zone 1 and 2, and has removed Zone 3 from its guidance. Refer updated barrier-kerb guidance.


Figure 2: Design chart for kerb–barrier combinations (modification of Figure C12.2 AGRD Part 6)

Kerb type

Speed (km/h) Barrier type

Zone Offset Distances

Zone 1 Zone 2 Zone 3

Barrier

> 80 GF & WRSB Not recommended

70-80 GF & WRSB 0m 4m + -

< 80 GF & WRSB 0m 2.5m + -

Semi-mountable

> 80 GF 0m 4m + 0 – 1m

WRSB 0m 4m + 1.2 – 1.8m

70-80 GF 0m 4m + 0 – 1m

WRSB 0m 4m + 1.2 – 1.8m

< 70 GF 0m 2.5m + 0 – 1m

WRSB 0m 2.5m + 1.0 – 2.0m

Mountable No restrictions

Notes: Offsets are measured to back of kerb. This creates an offset of 300mm to line of kerb which reduces the likelihood of nuisance impacts. In low speed areas, such as car parks, there are no restrictions on the location of kerbs and barriers. Guard fence offsets are measured to the face of W-beam. WRSB offsets are measured to face of barrier post. Post foundations are typically 450mm-600mm in diameter, hence ‘Zone 1’ includes the foundation install at back of kerb.

Zone 1: Preferred. The kerb’s ability to deviate the bumper height is diminished as the safety barrier is already engaged. Preferred offset is as close to back of kerb as possible.

Zone 2: Preferred. The barrier is sufficiently far away that for most bumper trajectory paths, the vehicle has returned to the ground and collides with the barrier at the expected bumper bar height.

Zone 3: Tolerable. While the vehicle has commenced or not quite completed the vaulting process, the height and dynamic behaviour of the vehicle bumper is in conjunction with the safety barrier tolerable collision zone. This may vary between barrier types given the mechanism of engagement.

N.C.: Non-conformance. The zone between the preferred and tolerable limits. In this zone, there is an unacceptable risk that a run-off road vehicle will collide with and breach the barrier. Rise of the bumper may cause it to ramp or vault the barrier while lowering of a bumper may cause it to underrun the barrier. For these reasons a safety barrier should not be installed in this “Non-conformance” zone.

Updated barrier-kerb setback guidance In 2020, Troutbeck completed a review of DoT’s guidance relating to barrier-kerb offset values. The following information has been provided from this report.

Barriers are evaluated using tests based on ‘worst practical’ conditions. The strength is tested with heavier vehicles and occupant protection with lighter vehicles. However, when testing the interaction of the vehicles and


barriers, the impact angle becomes important and the critical angle will depend on the vehicle’s suspension characteristics and to a lesser degree the kerb profile. It is therefore important to evaluate the kerb barrier interaction using a range of impact conditions. It is not reasonable to use full scale testing to evaluate all probabilities.

There is no easily recognised relationship between the kerb profile and the likely interaction. Flatter or steeper kerbs have approximately the same effect on the vehicle trajectories. The effect of kerb height on the trajectories is only noticeable when the front of the errant vehicle is within 0.5 m of the face of the barrier.

With the barrier behind the kerb, the vehicle’s trajectory is first affected by the kerb, which can then result in the vehicle not engaging with the barrier effectively. If the kerb was behind the barrier and the vehicle could engage with the barrier then the effect of the kerb could be reduced. Locating the barrier in front of the kerb is likely to result in a better outcome than with the barrier behind the kerb, although there is no testing that demonstrates this point and it is likely to introduce other installation and maintenance challenges.

The decision to use a kerb and a barrier needs to be aware of site drainage issues. In fact, the guidance should be more holistic and address drainage and safety together. The recommended guidance given below should be augmented with comments on drainage.

It is recommended that a non-proprietary G4 barrier be located either:

• With the face of the barrier no more than 0.2 m from the face of the top of the kerb. • With the face of the barrier more than 7.0 m from the face of the kerb for roads with operating speeds

above 85 km/h. This distance could be reduced to 6.0 m in constrained locations. • With the face of the barrier more than 4.0 m from the face of the kerb for roads with operating speeds

between 70 and 85 km/h.

It is recommended that flexible guard fence products and wire rope safety barriers be located either:

• be closer than 200 mm from the face of a kerb or further way than 7.0 m from the face of the kerb. It is noted that the 200 mm dimension may be problematic as the kerb generally has a flat section that would make it difficult to install a barrier so close to it.

Following this review, Table 5.3 has been significantly updated within v4.0 of the Supplement to AGRD Part 6. Most obviously, Table 5.3 no longer contains guard fence setback distances of 0.1m to 1.0m (from back of kerb), which limits the offset to traffic lane, when a kerb is installed on the edge line. In addition, it limits the default placement of underground drainage.

However, in recognition of the ongoing in-field performance of the historical setback range, DoT provides an Extended Design Domain (EDD) setback range for use in constrained urban situations. Refer the Supplement to AGRD Part 6. These ranges help designers achieve a barrier offset to traffic lane of 0.6m and 1.0m, in 70-80km/h and <70km/h environments respectively; however designers should not maximise the setback distance unless there is a justified reason (e.g. insufficient sight distance, underground services or high risk of nuisance impacts). Smaller setback distances minimise the potential vaulting risk, therefore designers must consider the site-specific risks of adopting a reduced barrier offset (refer Table V5.2A), before adopting the maximum setback value.

Flaring Flaring is often used to adjust the barrier offset to protect hazards or roadside features closer to the road.

However, flaring can also be used to maximise the protected area when there is insufficient length before the first hazard. While safety barriers work best during a glancing impact, the Manual for Assessing Safety Hardware (MASH) requires physical crash testing up to 25 degrees. This is based on an upper percentile of run-off-road departure angles across the whole network.

Although flaring may increase the impact angle and thus the impact severity during a crash, the likelihood for vehicles to exceed the 25-degree impact angle cannot be accurately predicted, and in certain situations it may be more beneficial to flare the barrier and capture a greater percentile of errant vehicle. I.e. those that leave the road at an earlier location.

Designers should acknowledge that flaring will increase the impact severity but also provide other benefits like a greater protected area. A short risk identification and assessment should be completed to understand which risks are higher based on the context. For example, at lower operating speeds (<70km/h), the nominal impact severity is already lower than testing, therefore a barrier flare may be acceptable.

The following figure shows that the point of need could be achieved with a flare.


Figure 3 – Point of Need with and without flare

5.3.14 Barrier Type (Step B6) Barrier selection requires knowledge of the system’s performance and characteristics. Each barrier system is unique and is often optimised to pass a certain crash test protocol. As such, each barrier system will have positives and negatives, which should be utilised to suit the site constraints.

Accepted safety barrier products All products accepted for use by the DoT are listed in RDN 06-04 and will have a DoT Letter of Acceptance issued to the System Supplier. Using a product that is not accepted for use by DoT represents an unacceptable risk to road users and the community.

Acceptance is based on the information supplied by the Proponent at the time of assessment. DoT must be informed of any changes to a product and will determine if a re-assessment is required.

Assessment process The assessment of road safety barrier systems, end treatments and related road safety devices is undertaken nationally by the Austroads Safety Barrier Assessment Panel (ASBAP) of which DoT is a member.

Generally, there are three main crash testing protocols that are adopted. These are (i) the Manual for Assessing Safety Hardware (MASH), (ii) the National Cooperative Highway Research Program Report 350 (NCHRP350), and/or (iii) the European Normative EN1317 (EN1317).

In accordance with AS/NZS 3845.1:2015 and AS/NZS 3845.2:2017, MASH is the current basis for crash testing protocol, therefore it is the DoT’s preference to select products that have undergone the full suite of MASH testing.

Suppliers (or proponents) seeking product acceptance for use on State-controlled roads in Victoria are referred to the ASBAP for an Assessment Submission Package. http://www.austroads.com.au/road-construction/barrier-assessment

Where an ASBAP assessment results in a recommendation for “acceptance”, the recommendation together with any Technical Conditions of Use (TCU) should be included in an application to the DoT Manager– Road Design & Safe System Engineering. It should be noted that whilst DoT will be cognisant of the recommendations of the ASBAP, including the Austroads TCU, DoT reserves the option to reject or condition the use of any road safety barrier system, product or device for use on State-controlled roads in Victoria.

DoT may rescind or modify at any time any product acceptance. This is particularly the case should the status of the acceptance be modified by the ASBAP or should acceptance be modified in any way in other jurisdictions.

Austroads Technical Conditions of Use (TCU) and DoT Conditions and Variants To improve national harmonisation, the DoT will adopt the Austroads Technical Conditions of Use (TCU) when deemed suitable. Where Austroads has issued multiple revisions of a TCU, users must adopt the revision specified and linked in RDN 06-04.

Where DoT has specific conditions or variants, they will be detailed in RDN 06-04 or provided in a separate Detail Sheet. Where DoT does not have additional conditions or variants, the column in RDN 06-04 will state ‘Nil’ and the Austroads TCU is adopted.

In special circumstances, the DoT may accept a road safety product that has not been assessed by the ASBAP and therefore does not have an Austroads TCU. As such, a DoT Detail Sheet will be provided.

http://www/


In effect, this means that DoT will adopt a mixture of Austroads TCUs and DoT Detail Sheets. This has been implemented in order to minimise duplication, encourage national harmonisation and optimise the steps between Austroads assessment and DoT acceptance.

To determine which TCU and/or Detail Sheet was effective at the time of tender, users must refer to the relevant version of RDN 06-04 – Accepted Safety Barrier Products.

Barrier type selection Barrier selection requires knowledge of a system’s performance and characteristics. Ideally, barrier selection is based on finding the optimal balance of multiple key factors, as shown in Figure 4. Whereby, the overall aim is to reduce the probability of fatal and serious injury to road users, acknowledging that a limitation in one component could reduce the effectiveness of the entire system.

While this approach can be difficult in a contract setting, where the driving factors of barrier selection are often; the minimum containment level, the working width and the cost to install, the following guidance is provided to assist designers and project engineers.

Figure 4: Key components of barrier selection

Containment Barrier systems with greater containment capacity (i.e. contain a wider range of impact scenarios) are preferred but can be costlier to install. At minimum, the system must provide the containment capacity defined by the client or determined in ‘Step B5 – Determine the containment level’ of the design process.

While the tested containment capacity for each barrier is set by the crash test protocols in AS/NZS 3845 (e.g. MASH TL-3), every system will have a probability of breach and a maximum containment capacity that may extend beyond the testing criteria. Maximum containment capacity can depend on several characteristics, such as the failure limit of the barrier, the barrier height and the vehicle-barrier engagement behaviour. Similarly, a system may not predictably contain all vehicle shapes and configurations even if some vehicles are significantly lower mass than the crash tested mass.

Figure 5: Flexibility of a range of barrier types (Burbridge 2020)


While these factors are difficult to quantify and have already been carefully considered during the product assessment process, they should also be considered by the designer as qualitative factors during product selection. Designers should recognise that there is unlikely to be a ‘perfect’ barrier system, therefore the containment level selection should be based on the defined needs of the site.

Impact severity Systems with a lower impact severity (i.e. less likelihood of injury) are preferred but often require more area for deflection and are likely to be more costly to install.

A new and important concept is that safety barriers should no longer be classified as “flexible”, “semi-rigid” and “rigid”, but should be classified by their flexibility. Permanent concrete barriers have zero flexibility, while steel rail and wire rope barriers have a range of flexibilities. Figure 5 demonstrates the range of flexibilities and that some steel rail and wire rope barriers have almost the same flexibility.

Occupant risk is a key acceptance criterion for barrier assessment, and all systems must perform below a defined threshold. While it is possible to compare the impact severity of a product, using an equivalent test, the severity on site is largely reliant on the installation conditions and the likely impact scenario.

As lateral offset to the barrier increases, the likelihood of it being hit diminishes, but more critically, the impact severity may increase as lateral offset enables slightly higher impact angles. This increases the probability of penetration, over-capacity impacts leading to containment failure, or more aggressive impacts.

Further, some barriers can be modified to reduce the impact severity for a specific road user impact (e.g. motorcyclist rub-rail). These attachments may have quantitative benefits (via certified testing) or qualitative benefits (via engineering judgement). Any combination of attachments must not affect the containment capacity of the barrier and should limit the effects on impact severity.

Site suitability The barrier system must have performance characteristics and values that are suitable for site, including working width, support depth & width, post type, length and terminal type.

Crash testing provides a reference point for establishing suitable performance, and unless the site can be modified to match the testing, the performance of the safety barrier may differ from the test results. Consequently, the site may deviate from the known set of performance values. Depending on the level of deviation from tested performance values, site constraints may preclude selection of certain barrier types.

Selecting a longitudinal barrier also requires a suitable terminal or the need to interface or transition into other systems. Like longitudinal barriers, each terminal and transition will have positives and negatives, and are often optimised for specific crash test reference points.

The ability to withstand a subsequent impact may also be important, including any lasting effects on the entire system.

Whole of life (reliability and maintainability) Systems that continue to function predictably, under the expected conditions for the intended time period, are preferred.

Designers should consider the operational conditions in which the system is to be installed, maintained and repaired. All systems require an inspection and maintenance regime. However, systems that are likely to fail or degrade, or that need frequent or complex maintenance and repair, will need a supporting inspection and maintenance regime.

Designers should consider the resources available to install the barrier system, in addition to the resources required to maintain and repair the system. The whole of life costs will vary significantly for each barrier system and the site circumstances, including location and road function. Inadequate installation, maintenance or repair can compromise barrier reliability.

Accessibility is another key factor for consideration. Systems which cannot be easily accessed, are likely to be left un-repaired or un-maintained for a longer duration.

The following is a summary of key factors;

• frequency of failure, • frequency of inspection,


• ease of fault identification, • ease of fault testability, • product maintainability, and • ease of fault repair • accessibility

The resource demands for an individual barrier may be influenced by the barrier design on an entire route or region. The fewer systems used, the fewer inventory items and the less storage space required. Simpler designs are also more likely to be constructed and repaired properly by field personnel.

Product comparisons

Product comparisons using different crash test protocols Performance results obtained from crash testing (e.g. deflection and working width) cannot be easily compared when conducted under different test protocols. For example, the dynamic deflection for a TL-3 system tested to NCHRP350 is not expected to be the same as the deflection of the same system tested to MASH TL-3, because of the differences in impact energy.

Comparisons made based on impact energy are possible (using vehicle mass, speed and impact angle), but such comparisons do not result in an equal level of predictable performance that crash tests provide. Mostly, real world barrier impacts are different to crash tested scenarios where mass, speed and impact angle can vary and therefore affect performance characteristics.

Due to the difference in crash tests, it is very difficult to make performance comparisons across different crash test protocols.

System specific comparison and selection In general, DoT prefers that all barrier designs are product-agnostic and are notated as per the Supplement to AGRD Part 6, Section V5.1.4. This promotes product competition and ensures that the most cost-effective product that meets the required design is used.

However, where a particular need is identified outside the current guidelines; the system supplier may be sought for advice and guidance of a barrier system’s performance in a non-standard installation. System specific designs shall be:

• based on valid crash testing data • supported with evidence from the supplier • documented with correspondence from the owner • specified on the safety barrier design drawings • certified by a DoT prequalified designer • approved by the contract Superintendent.

Any alterations made to the system specific design shall be endorsed by the original designer and supplier and approved by the Superintendent. Approved suppliers of each product can be found in RDN 06-04.

System specific designs may be considered when the proprietary product is known, and the barrier can be designed with consideration of product specific crash testing provided by the System Supplier. System specific designs should be made clear on the design plans (to avoid product substitution) and should be used in isolation of other systems (e.g. not connected).

Please contact the DoT Road Design & Safe System Engineering team to discuss any system specific designs that may have been identified for consideration on recent projects. System specific designs that have been successfully assessed may ultimately be included within the product acceptance for broader use.


Common safety barrier characteristics

Wire Rope Safety Barrier characteristics WRSB systems generally consist of the following components:

• Tensioned steel ropes - to engage and contain the vehicle; and smoothly redirect the vehicle away from the hazard

• Steel posts - to support the ropes at the height required to engage a vehicle; and to provide lateral resistance on the ropes during an impact, thereby reducing deflection. (i.e. more posts provide a lower deflection)

• Post foundations - to support the posts during an impact without movement, allowing damaged posts to be easily replaced.

• Anchor foundations - to anchor the tensioned ropes, allowing redirection away from the hazard during an impact.

• Delineator – a retroreflective sticker attached to the post cap to alert drivers of the WRSB position.

The following limitations, benefits and comments are typical of WRSB systems:

• The minimum allowable curve radius for WRSB installations is 200m as this is the lowest radius at which the system was successfully tested. Horizontal curves place more lateral load on the post foundations.

• 100m radius curves may only be used at emergency stopping bays, refer Appendix E. • The minimum allowable sag curve K value is 30. There is no K value limit for crest curves. Refer to AGRD

Part 3 for the definition of K value. • WRSB working widths increase when installed on curves and when the barrier is longer than 250m. Refer

Section 5.3.15.6. • Not compatible with continuous motorcycle protection. • Minimum proximity to the batter hinge point is 1m, to ensure the post foundation is supported. • Cannot be connected to other systems.

Guard fence characteristics Guard fence systems generally consist of the following components:

• Posts (strong or weak) – absorb some of the crash energy upon impact through post rotation in the surrounding soil. The post shape and strength will differ between products and will have the greatest influence on whether a system is considered flexible or semi-rigid;

• Blocks (only used in Type B & G4) – positioned between the rail and post to minimise vehicle snagging and reduce the potential for vehicles to vault over the barrier, by maintaining rail height during the initial stages of impact. Flexible GF has no block;

• Release mechanism – a critical component of all GF systems, designed to release the w-beam or thrie-beam during an impact to maintain desirable contact with the impacting vehicle;

• W-beam – longitudinal steel sections in the shape of a ‘W’, spliced together that work in tension to contact and redirect the vehicle away from the hazard;

• Thrie-beam – longitudinal steel sections in the shape of a ‘VVV’, spliced together that work in tension to contact and redirect the vehicle away from the hazard;

• End Terminals – designed to anchor the GF system and introduce the necessary characteristics required for safe vehicle impact and redirection throughout the length of need section.

• Delineator – Flexible plastic bracket with retroreflective material to alert drivers of the position of the GF system. Fastened to the top of the beam with a single bolt. Refer Standard Section 708.11.


Figure 6 - Typical guard fence systems

The following limitations, benefits and comments are typical of guard fence (w-beam systems):

• Infield examples of GF have performed well on the outside of curves, even those of relatively small radius, as the concave shape supports the development of tension in the rail.

• Installations on the inside of curves can be more problematic, as the convex shape can mitigate development of tension in the rail. However, this is usually only a problem for very small radii, such as those on the corners of intersections. In this case, designers should allow extra clearance behind the barrier for deflection.

• There are no vertical alignment limitations for GF installations. • Can be transition/connected to thrie-beam and Type F concrete safety barriers. • Barrier length, curvature and temperature do not affect the working width values. • Impact damage is localised and will not affect the entire barrier system. • GF is compatible with continuous motorcycle protection.

Concrete barrier characteristics Additional information on F-Shape concrete barriers can be found in the Detail Sheet for F-Shape concrete barrier.

Barrier selection examples Barrier selection is not a prescriptive procedure and designers should recognise that there is unlikely to be a ‘perfect’ barrier system. Barrier selection should be based on the key components above.

However, to assist with understanding and decision making, Table 1 provides informative notes on the common barrier types with summaries of known benefits and risks. Table 2 provides a list of common road characteristics and the typical preferred barrier type and provides a starting point which should be considered in conjunction with the principles above.

These tables are intended for information only, and do not prescribe DoT’s requirements.


Table 1: Generic strengths and weaknesses of longitudinal barrier types

Barrier flexibility (DD/IS)

High (>0.008)

High (>0.008)

Moderate (0.004 to 0.008)

Zero (~0.000)

Examples Wire rope safety barrier Flexible W beam systems Thriebeam Permanent concrete barrier

Containment capacity

Tested: MASH TL-3 to TL-4

Maximum: Added capacity is available in the cables with greater working width. Containment of larger trucks has occurred infield.

Highest potential for breach.

Rank: A-B

Tested: MASH TL-3

Maximum: Unknown additional capacity in the w-beam rail.

Medium potential of breach

Rank: B

Tested: MASH TL-4

Maximum: Little additional capacity in the w-beam. Release mechanism may tear rail during impact.

Medium to Low potential of breach

Rank: A

Tested: MASH TL-3 to TL-6+

Maximum: Significant capacity provided in the system.

Lowest potential of breach

Score: A+

Impact severity

Lowest occupant risk for passenger vehicle and truck occupants.

Not tested for motorcyclists. Post cushions provide minor benefit for motorcyclists.

Rank: A

Lowest occupant risk for passenger vehicle occupants.

Not tested for truck impacts

Rub rail provides known safety benefit for motorcyclists (EN1317.8).

Narrow post provides minor benefit to peds and cyclists.

Rank: A

Medium occupant risk for passenger vehicle and truck occupants

Rub rail provides known benefit for motorcyclists (EN1317.8). Post caps provide minor benefit

Rank: B

Highest occupant risk for passenger vehicle and truck occupants.

Acceptable occupant risk for commercial vehicles (36T)

Smooth surface provides minor benefit to motorcyclists and (not tested)

Rank: B

Site suitability

Large working width required.

Large performance variability due to cable tensions in the field.

WRSB terminals do not ‘absorb energy’. Should be offset from traffic lane.

Rank: C

Large working width required.

Little performance variability

Terminals will ‘absorb energy’ and redirect. Gating behaviour observed.

Rank: B

Medium to low working width required.

Little performance variability

Terminals will ‘absorb energy’ and redirect. Gating behaviour observed.

Rank: B

Small working width required.

No (negligible) performance variability

Crash cushions will ‘absorb energy’ effectively and are fully redirected.

Rank: A

Whole of life

Cables are likely to drop after impact and rope tension may be affected along the entire barrier.

Low cost to install per metre.

Low cost to repair per metre. Few tools needed.

Requires 10-20 (avg) posts replaced per impact.

Requires routine cable tensioning.

Reliability Rank: B

Maintainability Rank: B

Impact damage is localised and visible.


Medium cost to repair per metre. Barrier repair requires special equipment.


Reliability Rank: B

Maintainability Rank: A

Impact damage is localised and visible.


Medium cost to repair per metre. Barrier repair requires special equipment.


Reliability Rank: B

Maintainability Rank: B

Impact damage is rare, localised and visible.

Barrier is durable to vehicle impacts.

High cost to install per metre.

High cost to repair per metre, although rare. Barrier repair requires special equipment

Barrier is durable to vehicle impacts with no routine maintenance.

Reliability Rank: A

Maintainability Rank: A

Please note: The rank values provided in this table are based on general experience and observation of barrier performance. All barrier types have been assigned the same total in order to highlight the comparative strengths and weaknesses. These ranks may assist designers when tailoring a system to the site. All longitudinal barriers have demonstrated occupant risk values below the preferred threshold. The term low, medium and high described above is a comparative ranking, within the accepted levels. The rank values for ‘Site Suitability’ refer to the variety of sites and contexts that the barrier type is likely to suit. Higher ranks imply that the barrier type can be adjusted to suit more locations and contexts. While lower rank values imply the barrier type is suitable to fewer location, due to the space needed or installation constraints.


Table 2: Preferred barrier types for typical road characteristics

Typical road and barrier characteristics Available barrier flexibility Typical barrier type

Verg

e

Unconstrained roadside – with desirable barrier design

High WRSB, flexible w-beam systems

Reduced barrier offset – Less than 3m from traffic lane

Moderate to high Flexible W-Beam systems, Thriebeam.

Horizontal geometry less than 200m radius Moderate Flexible W-Beam systems, Thriebeam

Barrier lengths (between terminals) less than 100m Moderate to high Flexible W-Beam systems,

High risk motorcycle routes Moderate Flexible W-Beam systems (with rub rail attached)

Infrequent inspection and maintenance locations Zero to moderate Flexible W-Beam systems, Thriebeam or permanent concrete barrier

High severity hazards (e.g. vertical drop) Zero to moderate Thriebeam or permanent concrete barrier High occupant land use Zero to moderate Thriebeam or permanent concrete barrier

CV > 20% Zero Thriebeam or permanent concrete barrier High volume urban freeways Zero Permanent concrete barrier

Med

ian

Narrow/wide medians (>6.2m) without fixed hazards, excluding the scenarios above


Narrow medians (<6.2m) without fixed hazards, excluding the scenarios above


CV > 20% Zero to moderate Thriebeam or permanent concrete barrier High volume urban freeways Zero Permanent concrete barrier

Infrequent inspection and maintenance locations Zero to moderate flexible w-beam systems, Thriebeam or permanent concrete barrier

5.3.15 Determine the working width

Working widths for concrete barriers The Zone of Intrusion (ZOI) was a concept introduced in the AASHTO Roadside Design Guide (AASHTO, 2011). The concept described the areas where both the cab of a truck or the cargo deck of a single unit truck or the trailer of an articulated vehicle would intrude into the area above and behind a barrier.

Impacts with taller barriers result in less body roll and smaller working widths. The height of the cargo box in the TL-4 tests was typically 3.6 m high and the height of the trailer in the TL-5 tests was 4.06 m. Using data from Polivka et al (2005), Rosenbaugh et al (2007), Williams et al (2011), Sheikh et al (2012), Williams et al (2018) and Shiekh et al (2019), the recommended working widths for vehicles that are 4.6 m high are listed in Table V5.12 of the Supplement to AGRD Part 6, which is repeated here for convenience in Table 3.

Previously, the ‘point of contact method’ was used to measure vehicle roll to a height of 4.0m-4.6m. While this method is less precise than Zone of Intrusion, it is arguably more logical to users and simpler to calculate, and therefore is still considered a reasonable method to calculate working width for concrete barriers taller than 1300mm. The point of contact method assumes a straight line along the barrier face to the necessary height (typically 4.6m). Non-rigid products behave differently, therefore this method is not appropriate

Working widths are measured from the toe of the barrier. NDD working widths for concrete barriers include the truck box. Cabin roll values may be considered in constrained locations only, as design exception.


Table 3: Working widths for F-shape concrete barriers (Source: Supplement to AGRD Part 6, Table V5.12a)

Concrete barrier height (mm)

Test Level 3 Test Level 4 Test Level 5

2200 kg Pick-up truck Vehicle height = 2.0 m

10000 kg Rigid truck Vehicle height = 3.6 m

36000 kg semi-trailer Vehicle height = 4.1 m

Cabin (mm) Truck box (mm) Cabin (mm) Truck box

(mm) Cabin (mm) Truck box (mm)

820 6501 no box Not achievable Not achievable

920 500 no box 13804 2300 Not achievable

1100

System width2 no box

13204 2200 14404 2400

1300 9004 15003 9004 1500

>1300 Use point of contact method5

Notes: 1. This is a nominal value based in an intrusion of 450 mm plus the need to allow 200 mm for the width of the

foot and sloping sides of the barrier. Rosenbaugh et al (2018) recorded a working width of 504 mm in a vertical barrier.

2. This impact results in zero intrusion, and the working width is equal to the system width. 3. The assumed body roll for the TL-4 vehicle is the same as for the TL-5 vehicle 4. The height of the cabin in the tests being 2.7 m high, therefore the working widths for the cabin are 60% of

those for the box. 5. The point of contact method assumes a straight line along the barrier face (i.e. toe of barrier to top edge) and

extended to the necessary height (typically 4.6m). Refer Table 4b and Figure 7b.

Working widths for F-Shape concrete barriers with sway protection Sway protection for concrete barriers can be used to reduce the amount of vehicle roll above and beyond the barrier that would otherwise impact the hazard.

Sway protection is not necessarily intended to increase the containment level of the barrier, but can be used in the vicinity of a hazard for additional risk mitigation. Sway protection can be used to protect both the hazard/asset and vehicle occupant of a heavy vehicle. This is effective when the percentage of heavy vehicles is high enough to warrant protection from the hazard.

Sway protection is a modification to the barrier profile and should be used only when necessary.

When a typical passenger vehicle impacts the F-Shape, it mounts the kerb reveal and slides up the barrier before being redirected. Modifications to the upper profile may change the severity of the impact and should be avoided. All changes should retain smooth vehicle redirection and limit snagging; excessive protrusions with the sole intent of satisfying vehicle roll allowance is prohibited and can be unsafe.

DoT requires the modification to begin 920mm or more above the surface level to ensure the effects to smaller vehicles are reduced. In addition, DoT recommends a 30mm maximum protrusion to minimise snagging and impact severity.

An example of a concrete barrier with sway protection has been shown in Figure 7. Working widths for F-Shape concrete barrier with and without sway protection are provided in Table 4.

Figure 7 - Modification

for sway protection


Table 4: Working widths for F-shape concrete barriers with sway protection

Concrete barrier height (mm)

Test Level 3 Test Level 4 Test Level 5

Cabin (mm) Truck box (mm) Cabin (mm) Truck box

(mm) Cabin (mm) Truck box (mm)

1100

System width1 no box

13002 21703 14202 23703

1300 Use point of contact method4

> 1300 Use point of contact method4

Notes: 1. This impact results in zero intrusion, and the working width is equal to the system width. 2. The height of the cabin in the tests being 2.7 m high, therefore the working widths for the cabin are 60% of

those for the box. 3. Concrete barriers with ‘sway protection’ will have a top edge (face) that is 30mm closer to traffic than the

traditional F-shape. As such, these values have been reduced by 30mm. 4. The point of contact method assumes a straight line along the barrier face (i.e. toe of barrier to top edge)

and extended to a height of 4.6m. Refer Table 4b and Figure 7b.

Table 4b: Working widths for F-shape concrete barriers (>1300mm) (Source: Supplement to AGRD Part 6, Table V5.12b)

Concrete barrier height (mm) 1300 1500 1550 1700 1800 1900 2000 2100

F-Shape profile Table 3 825 815 785 765 750 735 725

F-Shape profile with sway protection 618 535 515 470 440 415 395 375

1. Working widths are based on the ‘point of contact’ method, which assumes a straight line along the barrier face (kerb reveal to top corner), extended to a height of 4.6m. These values have been rounded up. Working width is measured from the toe of the barrier.

2. Sway protection is a modification to the barrier profile to reduce the amount of vehicle roll above and beyond the barrier. Refer above for additional guidance.

Figure 7b: Point of Contact method for F-shape concrete barriers


Working width factor of safety While product suppliers are not required to test beyond the chosen test level, it is generally recognised that if an errant vehicle were to impact a barrier with less lateral energy than tested, the vehicle is likely to be contained. As such, a factor of safety (FoS) concept was introduced into the Supplement to AGRD Part 6 (2019) to cater for heavier/over-capacity vehicles on the network. While this additional allowance does not deliver a higher test level, it provides additional clearance for heavier vehicles on the network and is recommended when protecting assets without a specific containment level selection process.

The FoS is additional to the crash tested performance and is used for above ground assets on greenfield projects, where the designer can influence the location of roadside assets and especially where an asset may collapse onto a road user. On brownfield projects, the FoS is often not practical and the tested working width may be adopted.

Until withdrawn, Table 6.8 of AGRD Part 6 is considered a FoS distance. The values are not based on crash testing or computer-simulation, nor does DoT know the impact energy of the vehicle shown (4.6m tall) or how the barrier would interact with the bumper of such a vehicle.

Given that space is often limited on site, and the FoS is often difficult to achieve, it is critical that a suitable containment level has been selected for the site and the individual hazard. Where DoT requires that an asset is shielded from taller and wider vehicles, an appropriate test level barrier must be selected.

Constrained locations DoT recognises that the road network is constrained in many locations, particularly in urban environments. And throughout the design process, a designer is required to make decisions to maximise safety and practicality based on knowing which working width values are considered normal design domain (tested) and which values sit outside this domain, for use in constrained locations.

Using a higher containment barrier to reduce working width Vehicle roll is the lateral distance between the deflected face of a road safety barrier and the maximum extent of the vehicle body during impact. Significant roll is measured during the TL-4, TL-5 and TL-6 crash tests and is already included within the accepted working width value. As a result, the published working width values will often increase with higher Test Levels. While the safety barrier may be taller, the impact vehicle is also taller and a greater vehicle roll/sway will occur.

If a specific containment level is needed (e.g. TL-4) and the published working width for a matching product (i.e. TL-4) cannot be achieved, then the designer should intuitively consider a taller and/or more rigid barrier to reduce the working width/roll allowance. However, this often requires the designer to select a barrier that has been crash tested to a higher level, and there is often uncertainty about which working width value to use. For example, in the case of a concrete barrier, although the designer should consider using an 1100mm high TL-5 concrete barrier instead of a 920mm TL-4 barrier height, it is typical practice for the designer to use the published TL-5 working width value which is then greater than the original TL-4 system.

For this reason, it is acceptable in some cases to select a higher test level product (e.g. taller concrete barrier) and use the working width for the test level required. For MASH TL-4 products, the barrier is also crash tested to the MASH TL-3 conditions and therefore both working width values are provided for use.

For concrete barriers, Table 3 may be used to determine working width.

WRSB working width on fill batters The desirable verge width required between WRSB and batter hinge point is the full width of dynamic deflection as described in the Supplement to AGRD Part 6 – Section V5.3.15.5.

WRSB is designed and tested to work optimally when a flat traversable surface is provided behind the barrier (10:1 or flatter). Where this is not possible or the cost is prohibitive, a batter overhang concept (BOmax) may be applied to the dynamic deflection area as per the formula below and Figure 8.

The intent of this formula is to ensure that during a capacity impact at least one set of wheels of the vehicle will remain on the verge. This is considered to occur when the maximum deflection does not overhang more than 1.3m past the batter hinge point.


Vmin = Wmax – BOmax

Wmax = Maximum barrier deflection, see VRS Section 6.3.15.6; BOmax = Maximum batter overhang (1.3m); Vmin = Minimum verge width between the batter hinge point and WRSB

While 1.3m is the absolute maximum batter overhang allowable, smaller values are preferred where possible to ensure redirection can occur entirely on the verge. Designers will need to assess competing objectives such as the barrier offset to traffic lane vs. offset to the hinge point.

Figure 8: Verge widths for deflection

Note that this formula only applies to fill batters and table drains as the vehicle can pass over the hazard without impacting an unyielding hazard. Batter slopes beyond the batter hinge point should be maximum 4:1.

5.3.18 Barrier Length of Need (Step B11)

Using GD6111 and GD6112 GD6111 and GD6112 provide a range of common LoN values calculated using the run-out-length method detailed in AGRD Part 6.

To use these tables, the designer must know the protected width (i.e. the distance from the edge of traffic lane to back of hazard), the design speed, and the barrier offset. While these drawings provide a range of typical values, rounded up, designers may use the run-out-method in AGRD Part 6 to obtain a more accurate LoN value.

Table B provides an adjustment factor for lower AADT volumes, which is embedded within the Lr values provided in AGRD Part 6.

While the barrier offset values in Table A extend beyond the recommended 4-6m barrier offset, these higher values can be used when calculating LoN from the opposite direction (‘A Opposite’).

Downstream point of redirection The length of need is the length of barrier required to redirect the majority of errant vehicles and thus shield the hazard. Therefore, an appropriate barrier length is where the barrier system’s points of redirection (PoR) align with, or extend beyond, the hazards’ leading and trailing points of need (PoN).

ASBAP has recently published a Technical Advice on determining the downstream point of redirection, which should be used when designing barrier on one way roads (or single direction carriageways). While this concept is relatively new, this information should be considered by the designer.

5.3.19 Minimum Length of Barrier (Step B12) To perform satisfactorily, safety barriers must have sufficient length to enable vehicle redirection. In addition, barrier terminals require sufficient support to perform (e.g. absorb energy) as designed and tested.

However, it is common practice for designers to consider barrier lengths shorter than the tested value, especially in urban environments with numerous constraints. To assist with decision making, ASBAP has recently published a Technical Advice on the minimum length of guard fence. This guidance may be considered by designers.


5.3.20 Sight Distance (Step B13) All barriers must be considered non-permeable to the highest point on the barrier (e.g. top of post or W-beam rail) for the purposes of assessing sight distance.

The effect of barrier on sight distances, particularly on horizontal curves and in the vicinity of intersections and driveways, must be considered when selecting barrier offsets. The presence of vertical geometry should also be considered in conjunction with the horizontal geometry and the location of the safety barrier.

Safety barriers installed in narrow medians should allow for the median to be widened on curves, allowing better stopping sight distance for vehicles that need to stop in the case of a hazard on the road (e.g. debris). Refer to Section 5.5 and Appendix G of AGRD Part 3.

The typical mounting height from the top of the steel beam to ground surface level for GF is between 730-740mm for w-beam products and 980mm for thrie-beam. For WRSB products, the mounting height from the top rope to ground level is between 800-890mm.

Consideration may need to be given to raising driveways to provide sight distance over the top of a barrier, where the need for safety barrier is unavoidable.

5.3.21 Terminal Treatments (Step B14) Additional details on the performance of accepted terminal products can be found in the relevant Austroads TCUs or DoT Detail Sheets. This includes information such as system length, system width, variants, side slope limit and permitted foundations can be found.

WRSB intermediate anchors Although WRSB intermediate anchors are not listed in RDN 06-04, where the WRSB length proposed for a given site exceeds 250m, and the modified working width exceeds the available clearance behind the barrier, an intermediate anchor may be used to reduce the barrier length (Fl) used in the calculation of working width.

Depending on the specific barrier system, intermediate anchors typically consist of closely spaced separate barrier installations with overlapping points of redirection. Refer to supplier’s specification for details.

5.3.22 Transitions between Barriers (Step B15)

Barrier overlaps There is often a need to overlap two separate barrier lengths in a way that maintains continuous safety barrier and prevents errant vehicles from encroaching into the roadside.

Accordingly, all overlaps must be such that the terminating system is located in front (closer to the traffic lane) of the commencing system, with Points of Need (PON) intersecting at right angles to the travel lane. Where practical, full dynamic deflection of the terminating system should be provided between an overlapping flexible or semi-rigid barrier system. WRSB intermediate anchors may also be provided where practical.

Full dynamic deflection for the terminating system must be provided in any case where the commencing barrier system is rigid, such that an errant vehicle will not deflect into the blunt end of the rigid system.

5.5 Aesthetic Road Safety Barriers One method of making a safety barrier aesthetically pleasing is to simply have it painted. WRSB posts have been painted and installed on the network for several years now. Powder coated in heritage green paint, the posts blend in well with the surroundings. However, painting guard fence involves more effort given its size and surface area. Painted guard fence installations is not new in the urban area. There is no reason why a painted guard fence could not be considered in a rural setting, providing any resulting maintenance regimes are accepted. Delineation should not be an issue given most roads have a painted edge line and alignment signs where needed. Guard fence, in powder coated heritage green paint, could be aesthetically pleasing when installed on scenic installations, particularly on popular motorcycle routes. As such, both the w-beam and motorcycle rub rail would need to be painted, but not the posts as they effectively would be less visible from the roadway. If a project is considering installing painted guard fence in a rural setting, then its maintenance, potential for bushfire damage and whole-of-life costs need to be considered.


5.6 Other Road Safety Barrier Design Considerations

5.6.1 Barriers at intersections and driveways Short radius curve treatment A short radius curve treatment aims to redirect a vehicle where possible or absorb the energy of a vehicle impacting at a high angle. To achieve this, it requires frangible (timber) posts to break away, allowing the GF to wrap around the front of a vehicle and bring it to a stop. High angle impacts will deflect significantly allowing the vehicle to travel into a run-out area behind the barrier, refer Figure 9. The required run out area is clearly shown on the standard drawings and shall be provided.

Figure 9: Short radius curve deflection

Without a run-out area or breakaway posts, the vehicle will essentially be hitting a very stiff system at high speed and at a high angle, resulting in the vehicle to either under-ride the w-beam causing a large amount of occupant ride-down forces, or vault over the barrier into whatever hazard may be behind. In addition, double nesting shall not be provided as this would make the system even more rigid.

Following investigation into the work done by the FHWA (USA), short radius treatments have been successfully crash tested to NCHRP350 Test Level 2: 70km/h and are largely ineffective at higher speeds. Impact speeds above this can cause the vehicle to override or under-ride the barrier and could become more severe for the occupant than the hazard.

5.6.5 System Height The height of barrier is critical to its satisfactory performance and it is essential that this be maintained at the correct level throughout the life of the installation. The system height for each product is detailed in the product installation and maintenance manual.

System height upgrades Over the past decade, some products have increased in height to meet the newer crash test protocols. As such, some product (e.g. Type B) have attachments to increase the height (upgrade) of existing barrier installations without needing to re-install the system.

Where existing Type B installations are below standard height, lifting of the w-beam can be achieved with proprietary Abraham Blocks (Refer Figure 10).

Some flexible GF products can also be lifted retrospectively to be compliant with installation height requirements. Please refer to product manuals to see the accepted lifting components that can be used.


Figure 10: Abraham block

V5.6.6 Fauna Crossings On our roads, many animal species die per annum including some species of environmental significance. Fauna crossings may range from providing culverts, bridges, gaps within the barrier or rub rail, or fencing to restrict or corral fauna to an appropriate crossing point. A generic treatment on one project may not suit other locations or fauna, therefore, a specific treatment particularly suited to the local fauna and environment will need to be determined.

In general, wildlife should be discouraged from accessing roadways (other than low-speed and low-traffic volume roads) to minimise roadkill. Gaps in continuous WRSB and flexible W-Beam are not recommended. This advice is to be reviewed periodically by fauna experts, as more information becomes available on wildlife behaviour in roadsides with continuous barrier.

Safety barriers with motorcyclist rub-rail may obstruct the movement of wombats, echidnas, possums and other animals that are too large to squeeze under the rub rails. Where these species habitat nearby areas, gaps in the rub rail should be considered to allow animals to escape from the road.

When roads divide habitats and/or small populations of wildlife, expert fauna advice should be provided to assess the risk from reduced animal movement. For more guidance on the subject, it is recommended to contact Urban Design – Integration Services.

V5.6.7 Help phone bays The retention, installation or upgrading of help phones should be avoided due to the availability of mobile phones and other methods of incident detection. However, the DoT Help Phones Policy (2016) recognises that in high risk locations (e.g. lack of cellular coverage), the retention, installation or upgrading of help phones may be considered.

Where continuous barrier is proposed adjacent to a help phone bay, that is to be retained, the barrier must be flared and aligned behind the bay/phone to allow for normal access.

TC-2024 and TC-2025 detail the standard help phone bays installed on the Victorian network, both of which should be treated with a similar barrier alignment shown in Figure 4; smaller curve radii could be used for flexible w-beam systems.

Where existing kerb is present, it is desirable that a kerb-barrier offset shown in SD 3502 is provided, however, this may not always be achievable, and an alternative offset may be required for the short bay length. Where possible, a mountable kerb could be installed to limit the effects on barrier performance.

V5.6.8 Roadside bollards Bollards are currently being installed on the roadside for a variety of reasons. Given that roadside bollards do not have the same energy management or redirection capabilities as a road safety barrier, they should only be used in situations where a safety barrier is not feasible and where the hazard cannot be removed, relocated or redesigned.

Appendix A clarifies the types of bollards that have emerged and their preferred application. Before using a bollard, it is important to clearly define the key objective and show that the most suitable product has been selected. Appendix A provides guidance to assist in the selection process.


V5.7 Road safety barriers for vulnerable road users Consideration for vulnerable road user requirements, such as for pedestrians, cyclists and horse riders should be given when determining barrier layouts.

The rear side of posts and w-beam should be considered accordingly as a possible hazard for pedestrians and cyclists. Refer AGRD Part 6A and VRS to Part 6A for required path clearances and further guidance.

Consideration should also be given for appropriate end terminals located adjacent to paths. Some terminals are designed to gate, curve or kink the w-beam away from the impacting vehicle extending into the area behind the barrier system. These terminal types should be avoided where pedestrians and/or cyclists will be regularly accessing the area around the terminal.

Traditionally, barrier was seldom justified for the protection of pedestrians and cyclists alone, however Safe System principles recommend that vulnerable road users are separated from general traffic unless the speeds are low. Refer AGRD Part 6, Section 6.5.2 for further guidance.


3. Typical design philosophies When considering site constraints and context, it is extremely rare for two locations to be identical. Site-specific context will influence which design elements are most important, and also which design elements may be compromised.

This section provides a general design philosophy when designing barrier. Ideally, a barrier installation would meet all the desirable design values, such as offsets to hazards, kerbs and traffic lanes. However, where site constraints do not permit, the designer may need to create a typical design philosophy (i.e. order of preference) to assist with decision making.

The following philosophies provide support, and therefore should not be used without first checking if they are suitable for the site. All design decisions must be documented.

Typical design philosophy options for shielding hazards 1. Locate the barrier at 4.0m – 6.0m from the traffic lane. 2. Reduce the barrier offset from the traffic lane to minimum. 3. If for a short section, adopt a reduced post spacing for a sufficient length to protect the hazard 4. If WRSB, consider shortening the barrier length to avoid additional working width factors. 5. If WRSB, consider a stiffer barrier system such as guard fence, before reducing the offset to the traffic lane

below minimum. 6. Reduce the barrier offset from the traffic lane to absolute minimum 7. Consider the use of alternative terminal products that may provide for a greater length of redirection within

the length of terminal. 8. Consider the use of a rigid barrier system. 9. Reconsider removal or relocation of the hazard. 10. Undertake an appropriate risk assessment to justify the net benefit for safety barrier vs not installing a

safety barrier.

Typical design philosophy options for shielding fill batters 1. Provide a 10:1 traversable surface behind the barrier equal to dynamic deflection; 2. Provide a 6:1 traversable surface behind the barrier equal to dynamic deflection; 3. Consider a reduced post spacing to lower dynamic deflection (will increase barrier impact severity); 4. Consider an alternate barrier type to suit available offset to hinge point (will change barrier impact severity

& performance); 5. If WRSB, consider a batter overhang (BO). Vmin = 1.0m and BOmax = 1.3m, where batter slope is no

steeper than 4:1 (greater verge widths are preferred); 6. If WRSB, consider an increased concrete post footing size to provide Vmin ≤ 1.0m and BOmax ≤ 1.3m,

where the batter slope is no steeper than 4:1. 7. If WRSB, consider a Design Exception with careful consideration of risk. Absolute minimum BOmax ≤1.3m

where batter slope is no steeper than 2:1. (NB: risk must be carefully managed and an alternate barrier type is strongly recommended);

8. If GF, consider a Design Exception with careful consideration of risk. Some systems have been tested with reduced offsets to hinge point. 500mm absolute minimum.

9. Alternate barrier type required.


4. Barrier installation In order to install an effective barrier on site, the designer needs to provide sufficient information on the detailed design so that the installer does not need to create solutions on site, or second guess due to lack of information.

The Australian Standard defines this role as the Installation Designer, therefore it is important that the designer understands barrier installation requirements and is aware of solutions for common site constraints.

4.1 Documents for barrier installation To clarify the current relationship between safety barrier installation documents, the following structure has been provided in Figure 11.

Detailed Design Drawings – These drawings provide the final barrier design values (such as barrier length, location, and type) as determined during the barrier design process. These drawings will contain key decisions and any compromised solutions or values.

Standard Specifications – These documents provide requirements for the supply and/or installation of concrete safety barrier, steel beam guard fence (Section 708) and wire rope safety barrier (Section 711) systems and associated works.

Standard Drawings – These documents are the primary reference for manufacture and installation of public domain products.

Product Installation Manuals – These documents are the primary reference for final installation of proprietary products. They include component details and assembly requirements. It should be noted that while some product manuals contain design information (such as working width, offset to traffic lanes and product variants), these values and variants may not be accepted by DoT and installers should not be making or overriding key design decisions.

4.2 Quality assurance

Certificate of Compliance Due to the increasing complexity of proprietary safety barriers and terminals to install, and the lack of an installer accreditation scheme, DoT requires that all proprietary systems receive a Certificate of Compliance (CoC) by the System Supplier after installation.

The CoC provides assurance that the product has been assembled and installed in accordance with the product installation manual.

The CoC DOES NOT require the System Supplier to review, evaluate or “sign-off” the detailed design of the safety barrier system, such as barrier offset, barrier-to-hazard clearance, barrier flare, barrier selection etc. Safety barrier selection and design is an intricate process that requires the application of engineering judgement and risk assessment. Where the site is constrained, the designer must use relevant design guidance (e.g. AGRD Part 6), make appropriate decisions and document those decisions in a Design Report. The CoC does not validate or assure the design process.

Austroads Safety Hardware Training & Accreditation Scheme (in-development) The Austroads Safety Hardware Training and Accreditation Scheme (ASHTAS) is being developed to ensure the people who design, install, and maintain road safety barriers on Australia’s and New Zealand’s road network are appropriately trained.

Austroads has partnered with Lantra (UK) to develop a national accreditation scheme that will require the certification of all people engaged in the design, installation, and maintenance of any road safety barrier system used in New Zealand or Australia.

Austroads intends that the training courses run under the ASHTAS program will eventually cover a wider range of road safety hardware, essentially products covered by AS/NZS 3845 Part 1:2015 and Part 2:2017.

The ASHTAS structure for the accreditation training and delivery model comprises an installer’s pathway and a designer’s pathway.

Figure 11 - Barrier

installation documents

Detailed Design Drawings

Standard/Contract Specifictions

Standard Drawings

Product Specific Installation

Manual


4.3 Common installation solutions

4.3.1 Post depths on narrow verges When GF is used to shield embankments and the full width of dynamic deflection cannot be provided, consideration needs to be given to the provision of adequate ground support as, over time, softening of the verge may occur. Adequate post support is critical to ensure the barrier system will perform as intended.

A 500mm minimum clearance from the rear of the GF post to the embankment hinge point must be provided, although this may vary due to soil conditions, batter slope and post depth. Desirably the hinge point of batters steeper than 4:1 should be located outside the deflection width of the barrier.

If posts are placed closer to the hinge point than the minimum, it is recommended that the post embedment depth is increased to provide sufficient lateral support in semi-rigid systems.

Note some barrier suppliers have crash tested and/or analysed the performance of their proprietary systems at a clearance of less than 500mm away from the batter hinge point. 500mm is the minimum clearance and anything less than this should only be implemented in a constrained location with risk assessment and design exception. Documented evidence should be sought from the supplier to support any option assessment and decision making.

As a guide, additional post embedment depth of 1000/a mm should be provided for semi-rigid GF, where the embankment is aH:1V (refer Figure 10), limited to a maximum slope 2:1.

Alternatively, 2.4m posts (600mm additional depth) are commonly used on narrow verges. Consideration of the appropriate barrier system for containment on steeper slopes should also be given. For flexible GF, the plastic deformation of the post occurs at ground level. However, in weaker soils some suppliers recommend a longer 1770mm or 1860mm post, to provide sufficient lateral support during impact and facilitate the yielding action of the post.

Adoption of increased embedment depth as above should only be adopted on existing roads with constrained formation widths. Adequate formation width should be provided on all Greenfields projects and high risk retrofit projects.

Figure 12: Post depths on narrow verges

4.3.2 Post foundations for WRSB Adequate ground support must be provided to the posts and anchors to enable the barrier system to perform as designed.

WRSB posts shall be located in concrete ground sockets in accordance with the supplier’s specification. While it is always recommended that a geotechnical investigation is completed, the default post footing sizes shall be in accordance with RDN 06-04 unless a geotechnical investigation has been undertaken and an alternative size has been approved by the supplier.

Where the run-off road risk associated with heavy vehicles is particularly high, consideration may be given to larger post foundations than specified. Although larger foundations are not required for performance, it has been observed that impacts from heavy vehicles can cause the concrete foundations to pull out of the ground. This decision could be considered on a benefit/cost ratio for the project.

X

X


Deviations from standard post lengths should be stated on relevant design plans. Refer to Standard Section 708 for additional post installation requirements.

4.3.3 Avoiding underground services Where drainage or underground services are required at the GF location it is important that the drainage design and services strategy is coordinated with the barrier design. Items affected may include the location and depth of pipes/conduits and location of pits. Installations of GF along the inverts of table drains should be avoided for maintenance, durability and barrier performance reasons.

Where barriers are required across culverts or other underground services and two or more consecutive standard driven GF posts cannot be used, strengthening of the w-beam and/or omission of posts may be considered as follows. GF posts shall not be cut under any circumstances. Refer Standard Section 708 for installation details where posts cannot be driven.

Ground beam / shallow foundation The provision of a Type-B GF ground beam requires structural design and proof engineering by a prequalified design consultant and approval by the Superintendent.

Alternatively, several Flexible GF systems have surface mount posts which can be installed on a shallow concrete foundation. These variants must be installed in accordance with all supplier requirements and should be constrained to the area of need only, and not the entire length of barrier. Modifications to the accepted foundation design will need proof engineering and approval by the System Supplier.

Attaching surface mount posts directly to a culvert structure is also possible but requires structural advice and approval by the Superintendent.

Post omission Where necessary, a single flexible or semi-rigid GF post can be omitted to avoid a lateral underground asset, resulting in an isolated post spacing of up to 4-5m.

The omission of more than one post requires acceptance by the Department of Transport.

Post omission within Type B GF must also be nested to provide additional strength. Nesting of the w-beam is designed to increase lateral stiffness to compensate for the missing post and provide continuity of stiffness for vehicles, thereby minimising pocketing.

The recommended Type B post omission treatment is to nest and splice two layers of w-beam together in a ‘running bond’ configuration shown below (Figure 11). The length of nested GF should extend at least one w-beam length either side of the omitted post and should not be used in conjunction with reduced post spacing.

Figure 11 - Nested guard fence rail

If factory drilled nested w-beam sections are not available, the additional holes required for bolting of the nested w-beam should only be formed by drilling. No holes shall be formed or enlarged using oxy-acetylene equipment (“gas-axe”) or similar flame cutting methods. Once formed, the holes should be filed to remove any rough edges and painted with a single pack zinc-rich primer that meets AS/NZS 3750.9. Source NZTA TM-2003: Nesting of semi-rigid guardrail.


Combinations of nesting and reduced post spacing should only be used as per technical advice to avoid pocketing.

Nesting of flexible GF will not provide measurable performance benefits and should not be used.

Figure 12 - Post omission configuration

Twin block outs Where isolated individual (i.e. single) GF posts cannot be installed due to underground services, twin blockouts are acceptable on Type B to allow the post to be setback further from the w-beam. More than two stacked blockouts has the potential to lift the w-beam as the post rotates back during an impact and therefore should not be installed.

4.4 Maintenance strips The decision to install a safety barrier maintenance strip, concrete or otherwise, should be based on the benefit that it will provide. This decision should be made during the design development stage, before installation, as it will depend on the context, local maintenance needs and feedback from local stakeholders.

For lengths of continuous barrier in rural locations, the use of maintenance strips is generally not economical unless a specific need has been identified for a short section of the overall route.

In urban environments, maintenance strips are highly likely to assist with local maintenance practices and should be considered for use.

Before adopting a concrete maintenance strip, designers should consider current practices (including mowing equipment) and other maintenance solutions (such as controlled grasses) that could mitigate the need for a maintenance strip.

Types of maintenance strips

The most common type of maintenance strip in Victoria, is the concrete maintenance strip shown on SD3503.

Other maintenance strip types, such as geotextile fabrics, are available for use although they have not been widely implemented in Victoria. Where other maintenance strip types will provide benefit, they must be evaluated carefully prior to use, to minimise the potential for a long-term maintenance burden.


5. References 1. AS/NZS 3845.1:2015 – Road safety barrier systems 2. AS/NZS 3845.2:2017 – Rod safety devices 3. Austroads Guide to Road Design – Part 6 (2020) 4. DoT Supplement to Austroads Guide to Road Design – Part 6 (2021) 5. Road Design Note 06-04 – Accepted Safety Barrier Products 6. Standard Section 708 – Guard fence installation 7. Standard Section 711 – WRSB installation 8. An explanatory model for quantification of road safety barrier impact risk, Burbridge 2020

6. Appendices

APPENDIX A Roadside Bollards

APPENDIX B Wire Rope Safety Barrier deflection calculation

APPENDIX C Procedure to determine the length of redirection of a WRSB

APPENDIX D WRSB worked example

APPENDIX E Emergency Stopping Bay (ESB)

APPENDIX F Continuous safety barrier summary sheet

APPENDIX G Typical barrier drawings

7. Revision History

Version Date Clause Description of Change

1.0 August 2021 All

First version - This document consolidates guidance from RDN 06-02, RDN 06-08 and RDN 06-15, as well as other DoT internal documents. This document provides additional commentary on

• Working widths for concrete barrier • Barrier setback distances from kerb

8. Contact Details Manager – Road Design and Safe System Engineering Road and Traffic Engineering, Department of Transport 60 Denmark St, Kew Vic 3101 Email: [email protected]

mailto:[email protected]


Appendix A – Roadside Bollards Bollards are being installed on the roadside for a variety of reasons. Given that roadside bollards do not have the same energy management or redirection capabilities as a road safety barrier, they should only be used in situations where a safety barrier is not feasible and where the hazard cannot be removed, relocated or redesigned. This technical alert clarifies the types of bollards that have emerged and their preferred application. Before using a bollard, it is important to clearly define the key objective and show that the most suitable product has been selected. This technical alert provides guidance to assist in the selection process.

In general, there are four main categories of bollard.

Category Testing Objective Road Safety Device

Compliant crash testing to AS/NZS 3845.2:2017.

Used to shield hazards and/or other roadside features from an errant vehicle

Protection Device

Compliant or Modified crash testing based on AS/NZS 3845.2:2017. (may not comply with occupant injury criteria)

Used to protect pedestrians or high-severity hazards from errant vehicles in low-speed environments.

Roadside Furniture

Non-compliant testing, engineering analysis or not tested.

Used for delineation, physical obstruction or minor asset protection in product suitable locations.

Vehicle Security Barrier

Compliant crash testing for ‘Hostile Vehicle’ purposes - IWA14–1: Vehicle security barriers. Impact severity for errant vehicles to be minimised through design.

Used to stop a hostile vehicle attack in accordance with IWA 14-2 and relevant guidelines. Impact likelihood and severity for errant vehicles to be minimised via speed and location or roadside protection.

Preface All bollards have an element of risk. As such, bollards should only be used when the objective of the bollard is achieved, and the associated risk can be managed. While DoT prefers bollards with greater energy absorption capabilities, we recognise the benefit of product customisation to suit certain objectives. Product developers often choose a balance between containment capacity, energy absorption and practicality, realising that higher containment will cost more, and greater energy absorption will require a more complex and less practical system. Bollard selection requires an understanding of the bollard benefits/limitations and the site conditions.

AS/NZS 3845 notes that modern vehicles are designed with multiple crashworthy systems, such as airbags, seat belt pretensioners and crumple zones, that can tolerate impact speeds up to 50km/h. As such, a generic bollard (set in an appropriate foundation) with no energy dissipation characteristics could pass some crash test requirements.

Acknowledging that the majority of vehicles can manage energy transfer during a head-on low speed impact (<50km/h), it is critical that ALL bollards (& other devices) can prove a maximum level of containment and ensure that when they are impacted, they do not penetrate or show potential to penetrate the occupant compartment or present an undue hazard to other traffic, pedestrians or personnel in a work zone. Likewise, the collision with a bollard should not cause the vehicle to excessively roll or pitch in order to provide the driver every opportunity to regain control of their vehicle. Tested products, with a known performance level and behaviour, must be used, especially where vulnerable road users are being protected.

Bollard Categories

Road Safety Device All road safety devices must be submitted to the Austroads Safety Barrier Assessment Panel (ASBAP) for national assessment. Road Safety Devices accepted by DoT are published in RDN 06-04. These devices must be installed as tested to ensure an equivalent performance to AS3845.2:2017 – Road safety devices.

Performance • Bollards must be crash tested in accordance with AS/NZS 3845.2:2017 to be classified as a compliant

‘road safety device’. This standard requires products to demonstrate an acceptable level of crashworthiness for a specified containment level and are evaluated for structural adequacy, occupant risk and vehicular trajectory.


Application • Road safety devices may be used in locations up to the tested speed (e.g. TL-1 at 50km/h) and can be

considered in situations where safety barriers are inappropriate due to space limitations, pedestrian accessibility and/or aesthetics.

At present, DoT is unaware of any bollard that satisfies current crash test protocols. As such, the Energy Absorbing Bollard (EAB) has been recognised for meeting a previous standard (AS3845:1999) to Test Level 0: 1600kg car at 50km/h. Given that this standard has been superseded, the EAB is no longer considered a compliant road safety device and should only be used after a site-specific risk assessment. Refer Product Detail Sheet. The EAB should only be used as road safety device after all compliant systems have been considered and if the hazard cannot be removed, relocated or redesigned - cost should not be a key factor. The EAB may also be considered as a Protection Device, in accordance with below.

Protection Device Bollards used to protect vulnerable road users, or high-severity hazards are classified as a ‘Protection Device’. Protection devices should only be considered when a road safety device is not feasible.

Given the necessity to have pedestrians near the road, there is a need for products to protect high volume pedestrian areas from errant vehicles, with negligible deflection. While these devices are not considered a ‘road safety device’, without passing all the occupant evaluation criteria, they do offer a proven containment level and may be suitable to protect pedestrians from errant vehicles in low-speed environments (refer application).

While energy absorption characteristics are desirable, via a cartridge or steel deformation, protection bollards are unlikely to pass the minimum occupant injury criteria per AS/NZS 3845, given the need to test unrestrained occupants. As such, protection bollards may be used in certain applications and must be able to contain an errant vehicle and not present an undue risk during impact.

Protection devices often balance containment level, energy absorption characteristics and cost. As such, specific performance is dependent on the product design. These devices must be considered on product merit in accordance with this alert. For this reason, protection devices should not be substituted during construction without seeking comment from the original designer. Consultation with the product supplier is essential, to understand the products capabilities, benefits and limitations.

Performance • Protection Bollards must be crash tested using AS/NZS 3845.2:2017 as a reference point (e.g. vehicle

mass, speed and installation requirements). Any departures or differences must be documented and must be readily available on request.

• Protection Bollards must demonstrate, through crash testing, that they do not penetrate or show potential to penetrate the occupant compartment or present an undue hazard to other traffic, pedestrians or personnel in a work zone (e.g. debris). This test should be at the maximum containment level. Consultation with the supplier is essential.

• Protection Bollards must establish a maximum containment level via crash testing or engineering analysis (LS-DYNA). Containment level is defined by the maximum vehicle weight and speed to be contained (e.g. 2,270kg at 50km/h). The MASH 2,270kg pick-up truck is recommended for testing as this covers the 90th percentile of passenger vehicles.

• Protection Bollards must record and document occupant risk values in accordance with crash testing protocols. Although results will not be evaluated as pass or fail, they must be documented and readily available on request. Lower occupant risk values are preferred.

Application • Protection Bollards must be installed on roadsides with an operating speed of 50km/h or less. This allows

the impact energy to be managed by the vehicle, assuming the bollard does not fail, penetrate the vehicle

Protection Bollard: Vehicle contained, crumple zone and airbags deployed, bollard did not spear or cause undue risk to others.


or present an undue risk to others. Vehicle occupants are most vulnerable during side impacts (some research suggests 30km/h); therefore, the risk of side impact should be minimised, e.g. not near an intersection or tight curve.

• Protection Bollards must only be used to shield vehicles from pedestrian frequented areas (e.g. dining areas and tram stops).

• Protection Bollards must not be used to shield roadside hazards, unless the impact severity of the hazard has been demonstrated to be substantially more than the impact severity of the bollard, e.g. large drop-off or spearing hazard. Hazards such as trees, poles, piers and other rigid point hazards do not have a substantially higher impact severity.

• Protection Bollards must be installed in accordance with the manufacturers’ guidelines and specification. Adequate foundation strength is critical for performance, and any differences to the crash tested conditions must be factored into containment level or design.

DoT does not publish a list of accepted Protection Devices. Designers and/or asset owners should seek documentation from the supplier (e.g. crash test reports, occupant risk values, product details, etc), consider the objective and document their design process in accordance with the requirements above.

Roadside Furniture Bollards that have NOT been crash tested are classified as ‘road furniture’. They may only be used in situations where there is no requirement for protection from/for errant vehicles. These bollards are made from various materials and are often used for delineation, minor asset protection or to create a physical obstruction.

Delineation Bollards used for delineation, often made from plastic, must be designed such that they do not create an undue hazard for the vehicle occupants or nearby traffic when impacted. While crash testing would provide a better understanding of impact behaviour, lightweight and flexible materials (e.g. plastic) are generally considered satisfactory.

Access Restriction Bollards used for access restriction, often made from steel or timber, are considered hazardous to all road users and must be treated as such. Without crash testing, these bollards do not have an established level of containment (cannot guarantee protection from an errant vehicle), nor a certain impact behaviour or mechanism of failure (potentially hazardous). While there may be situations where these devices are appropriate, they should be labelled ‘not a road safety device’ and are only recommended in very low-speed environments or where they cannot be impacted (e.g. behind barrier). These bollards are also hazardous to cyclists and other vulnerable road users and their location should be carefully considered.

Frangible bollards Some bollards are considered ‘frangible’ (e.g. 100m x 180m timber post with a 75mm dia. hole) given their size and/or weakness in one direction. These bollards cannot guarantee protection from an errant vehicle and the impact behaviour is unknown. To be deemed frangible, these devices must be manufactured and installed in accordance with Australian Standards and DoT guidance. DoT recommends their use is limited to very low-speed environments or where they cannot be impacted (e.g. behind barrier).

Steel Bollard: Access restriction, containment unknown, impact behaviour unknown.

Timber Bollard: Access restriction, unknown containment, impact behaviour unknown- deemed frangible in one direction.

Plastic Bollard: Flexible design, often used for delineation.


Vehicle Security Barriers (VSB) Unfortunately, vehicles can be used with hostile intent to breach a perimeter, ram and damage infrastructure or as a weapon to injure and kill people.

Hostile Vehicle Management (HVM) uses a blend of traffic calming measures to slow down hostile vehicles and vehicle security Barriers (VSB) to stop those hostile vehicles progressing further. VSBs provide the hard stop for penetrative vehicle attack, they are structural in nature and can be either Active (powered or manual) or Passive (static). Active measures include hinged and sliding gates, boom barriers, retractable blockers and retractable bollards. Passive measures include structural wall, passive bollards and planters.

Performance The impact performance standards for VSBs are IWA14–1: Vehicle security barriers, and PAS68, both of which include a range of test vehicles and evaluation criteria.

• IWA 14 Part 1 specifies the essential impact performance requirements for a vehicle security barrier (VSB) and a test method for rating its performance when subjected to a single impact by a test vehicle not driven by a human.

• IWA 14 Part 2 provides guidance for the selection, installation and use of vehicle security barriers (VSBs) and describes the process of producing operational requirements. Each site will require a specific assessment to understand maximum speeds and angles of attack achievable by a hostile vehicle. This process is called a vehicle dynamics assessment and profiles all the approach routes. This allows the countermeasures to be designed to an appropriate level, preferably not over or under-engineered

Although VSBs are designed and tested with the intent of stopping hostile vehicles, they are often used in locations where they may be impacted by an errant vehicle and therefore should be designed to diminish impact severity. Unlike hostile vehicle attack, errant vehicle impacts can be predicted from the road characteristics (e.g. posted speed) and can be managed through other factors such as speed calming and control.

Like protection bollards, it is acknowledged that many vehicles can manage energy transfer during a low-speed impact, assuming the device does not present an undue risk during impact such as the potential to penetrate the vehicle or cause harm to others. As such, it is critical that VSBs are designed (shaped), positioned and orientated with an errant vehicle impact in mind. This includes smooth surfaces, rounded edges and a large contact surface

that will distribute energy. Components that are likely to leave the system during impact or may spear a vehicle must be avoided. Physical crash testing is the preferred method of testing.

Application • VSBs must be used in accordance with IWA 14 and other relevant hostile vehicle guidelines. i.e. There

must be an evidence based threat of attack. • VSBs must be installed on roadsides with an operating speed of 50km/h or less. This allows the impact

energy to be managed by the vehicle, assuming the device does not penetrate the vehicle or present an undue risk to others.

Higher operating speeds must be crash tested or require roadside protection such as an accepted safety barrier.

VSB Bollard: Similar severity to other roadside hazards, does not present undue risk to occupants or others, must be located within a low speed environment.

VSB Wedge: Smooth surface will distribute impact energy, can be deactivated as needed. Edges are shielded and cannot be impacted head on.

VSB Gate: Narrow impact point will focus energy into the occupant compartment causing undue risk to errant vehicles. This device should be located such that it cannot be impacted by errant vehicles.


• VSBs must be installed in accordance with the manufacturers guidelines and specification. Adequate foundation strength is critical for performance and any differences to the crash tested conditions must be factored into containment level or design.

DoT does not publish a list of accepted VSBs. Asset owners should engage a qualified security consultant, consider the conditions above and document their design and decision process.

Summary 1. All bollards have an element of risk and should only be used in situations where there is a need and a

safety barrier is not feasible. 2. Before selecting and installing a bollard, designers and/or asset owners must clearly define the objective of

the bollard (what it is trying to achieve) and demonstrate that a suitable product has been used. Objectives may include shielding a vulnerable road user or hazard, providing delineation or preventing hostile vehicle attack.

3. Other than ‘road safety devices’, tested in accordance with AS/NZS 3845, DoT does not evaluate or maintain a list of approved bollards. As such, practitioners must understand and document the benefits, risks and performance of the bollard by working closely with the product supplier.

4. Bollards must meet the performance requirements as specified in this technical alert. 5. Bollards must be used in an application specified in the technical alert. 6. Given the differences in product performance, bollards must not be substituted without seeking comment

from the original designer, as this may affect the original intent.

If you have questions, please feel free to contact [email protected] or contact (03) 8391 7191.

mailto:[email protected]


Appendix B - Wire Rope Safety Barrier deflection calculation factors

Please note, this appendix has been moved from ‘RDN 06-02 – The use of wire rope safety barriers (2016)’ and is largely unchanged. This appendix will be reviewed in the next edition of the document. The universal deflection values provided in Table 3 are based on the NCHRP 350 crash test protocol and are now superseded. As such, designers should refer to the product specific values contained within relevant Austroads TCUs. DoT is currently reviewing the need to re-establish universal WRSB deflection and working width values.

The tables below contain the standard barrier design deflections (Dstd) and correction factors (Fl, Fc) required to calculate the maximum barrier deflection (Dmax) . (Dmax = Dstd x Fl x Fc)

A.2 Dstd –Standard barrier design deflections at accepted post spacings “Working width” or “dynamic deflection” shall be adopted, from Table 3 below, as the required standard barrier design deflection.

Table 3: Dstd – Standard barrier design deflections1,2

Post spacing class Reduced Standard

Post spacing 2.0 m 3.0 m

Working Width standard (4-12 Test) 1.9 m 2.3 m

Dynamic Deflection standard (4-11 Test) 1.5 m 1.8 m

Notes: 1. Values based on straight barriers, up to 250m long between anchors. 2. Values based on barriers with concrete post footings. 3. Design deflections are based on NCHRP Report 350 Test Designations 4-11 and 4-12. See selection of ‘dynamic deflection’ or ‘working

width’ for Dstd below.

A.3 Selection of “Dynamic deflection” or “working width” for Dstd The selection of either “working width” or “dynamic deflection” as standard barrier design deflection Dstd, is dependent on the type of hazard being shielded. This can be simplified into two cases;

Case 1 – Where the hazard can be impacted by the vehicle roll allowance (e.g. pole or tree), “working width” shall be used. This is the preferred case for all situations.

Figure 6: Case 1 hazard

Case 2 - Where the hazard is low enough that it does not interfere with the vehicle roll allowance beyond the barrier (e.g. batter), “dynamic deflection” is considered sufficient.



For these two cases, the “working width” and “dynamic deflection” values, quoted in Table 3 above, have been based on the results measured during NCHRP 350 crash test designation 4-12 and 4-11, respectively, which are considered a severe case for each hazard type.

As discussed in Section 2, each accepted WRSB system must demonstrate satisfactory crash testing in accordance with NCHRP report 350 to at least Test Level 4. This includes passing the following NCHRP 350 test designations:

4-10: 820 kg car at 100km/h and 20 degrees

4-11: 2,000 kg pickup at 100km/h and 25 degrees

4-12: 8,000 kg truck at 80km/h and 15 degrees

As a simplistic overview; the 820 kg vehicle impact ensures a low riding vehicle is captured by the barrier and the occupant ride down is acceptable. The 2,000 kg vehicle impact represents a worst case, high energy impact, generally resulting in the greatest dynamic deflection. And the 8,000 kg vehicle impact demonstrates containment for a higher centre of gravity vehicle, generally resulting in a larger working width than dynamic deflection due to the vehicle roll allowance beyond the barrier. As such, the WRSB “dynamic deflection” values are based on the 4-11 crash test where no vehicle roll and the greatest overall dynamic deflection was demonstrated, while the WRSB “working width” values are based on the 4-12 crash test, which resulted in a lesser dynamic deflection (than 4-11) but a greater overall working width beyond the barrier. Refer product crash test results for performance details.

Fl – Barrier length correction factors The Fl to be adopted should be selected from Table 4 below.

Table 4: Length correction factors (Fl)

Rope length (m)1 Correction factor Fl

0 - 250 1.0

251 - 350 1.1

351 – 5002 1.15

> 5002 1.2

Notes: 1. Rope length is the total length of wire rope between anchor connections. (i.e. including terminals).

2. Deflection will continually increase as the wire rope length increases. Maximum barrier length shall be 1km. Fc – Barrier curvature correction factors

The Fc to be adopted should be selected from Table 5 below for all installations except those where impacts are only possible on the concave side of the curved alignment. For installations where impacts are only possible on the concave side, an Fc of 1.0 shall be adopted irrespective of curve radius.


Table 5: Curvature correction factors (Fc)

Barrier radius (m) Correction Factor Fc

200 - 400 1.5

401 - 500 1.4

501 - 600 1.3

601 - 800 1.2

801 - 1500 1.1

> 1500 1.0

Notes: 1. Where the barrier alignment is straight, adopt Fc = 1.0

Concave side

Convex side

A.4 Non-conforming or system specific designs If the requirements cannot be met, a non-conforming or system specific design may be considered in accordance with the Superintendent, only after the use of a stiffer system of similar containment has been considered. The use of a non-conforming or system specific design can be advantageous over a lower containment barrier, such as guard fence, as the extra containment of a TL-4 system means protection for a larger range of vehicle types, especially if the impact energy is expected to be less than tested.

Non-conforming design Where site conditions prevent the use of “working width” with case 1 hazard types, “dynamic deflection” may be considered for above ground hazards where a documented non-conforming design report has been completed, endorsed by Manager - Road Design and Safe System Engineering and approved by the Superintendent.

This non-conforming design report shall demonstrate that the expected vehicle impact conditions on-site are reduced from the crash tested conditions. Including but not limited to a:

• small future vehicle fleet mix, • reduced operating speed, • lesser likely impact angle, and • low probability of an impact.

By demonstrating that the 4-12 impact condition (8,000 kg truck at 80km/h and 15 degrees) is not expected on site; the deflection recorded during crash testing may not be expected and the “dynamic deflection” standard may be used as an absolute minimum case; ‘case 3’ below.

Direction of travel

WRSB

Correction Factor Fc = 1.0 shall be adopted irrespective

Direction of travel

WRSB

Correction Factor Fc – Refer Table 5



The documented non-conforming design report for case 3 shall be endorsed by the Manager - Road Design and Safe System Engineeringand approved by the Superintendent and submitted to the final barrier supplier for review.

System specific design Alternatively, where a specific product is known (e.g. an existing installation), the system supplier may be sought for advice and guidance of a specific systems performance. The system specific design may use data from the specific product crash testing as provided and approved by the product owner. System specific designs shall be:

• supported with evidence from the supplier, • documented with correspondence from the owner, • specified on the safety barrier design drawings, • certified by a DoT prequalified designer, and • approved by the Superintendent.

Any alterations made to the system specific design shall be endorsed by the original designer and supplier, and approved by the Superintendent. Approved suppliers of each WRSB system can be found in RDN 06-04.

All system specific designs shall use an accepted post spacing, specified in Table 3 (2.0m and 3.0m), with the exception of retro fit or context sensitive design exceptions. The use of alternate post spacing that have been crash tested shall be endorsed by the Manager Road Design and Safe System Engineering , and approved by the Superintendent.

Appendix C - Procedure to determine the length of redirection of a WRSB

Please note, this appendix has been moved from ‘RDN 06-02 – The use of wire rope safety barriers (2016)’ and is largely unchanged. This appendix will be reviewed in the next edition of the document.

This procedure describes how to determine the minimum WRSB length of redirection (LOR) required to shield a hazard. A hazard in this context is defined as an obstacle or feature located on the roadside that may result in a higher severity accident when impacted by a vehicle than would be expected from a vehicle impacting the barrier. Refer to VRS Part 6 - Section 6.0 for discussion of hazards.

As a simplistic approach, the two main principles include:

• Using an accepted method to determine the required point of need for a hazard. The required point of need is the first point at which a road safety barrier is required to prevent an errant vehicle from striking the hazard. Barriers closer to the hazard are shorter in length. DoT preferred method is the “Run-Out Length method” specified in AGRD Part 6 Section 6.3.19. Refer also SD 3521 and 3573.

• Selecting a barrier product that can provide the redirective capabilities required between points of need; the minimum barrier length of redirection. Aligning the barriers POR with the required point of need will provide this minimum length of adequate protection.


Figure 9: Required point of redirection

The barrier POR location and configuration of the terminal is different for each WRSB product and should be confirmed with the supplier when the POR is critical. Where the POR is not critical, 12m from the beginning of the barrier may be assumed.

Reference should be made to Standard Drawing SD 3521 and 3573 in using this procedure.

1. One-way traffic 1.1 Locate the WRSB as close to the hazard as possible according to the instructions in Sections 4 and 5 of this

RDN.

1.2 Determine the operating speed of the road alignment and the one-way AADT (approach volume). Refer to AGRD Part 3 - Section 3.0

1.3 Determine the width of the clear zone by referring to VRS Part 6 - Section 4.2 using the speed and volume from Step 1.2. The width of the clear zone is measured from the edge of the traffic lane nearest to the hazard.

1.4 Referring to Standard Drawing SD 3521 determine the distance “A” from the edge of the traffic lane to the WRSB and the protected width “B” from the traffic lane to the outermost point on the hazard.

1.5 Determine the minimum point of need (i.e.“Z” length) from Table B of Standard Drawing SD 3521. (multiply the “Z” value by the future AADT correction factor also in Table B of SD 3521)

1.6 Locate the barrier POR at the calculated point of need. Length of redirection (LOR) = Z (approach) + length of hazard.

2. Two-way traffic 2.1 For the near-side traffic, determine point of need (i.e.“Z” length) on the approach end of the near-side traffic by

repeating Steps 1.1 to 1.5 above.

2.2 For the far-side traffic, determine the point of need (i.e.“Z” length) on the approach end of the far-side traffic by repeating Steps 1.2 to 1.5 above, noting that the width of the clear zone and the distances “A” and “B” are measured from the centreline of the carriageway as shown in SD 3521.

2.3 Locate the barrier POR at the calculated points of need, providing a barrier LOR for the required length. Length of redirection = Z for the near-side traffic + length of hazard + Z for the far-side traffic.


Appendix D – Worked WRSB example

Please note, this appendix has been moved from ‘RDN 06-02 – The use of wire rope safety barriers (2016)’ and is largely unchanged. This appendix will be reviewed in the next edition of the document.

Design input

Alignment 700m radius curve

Traffic volume 7,000 vehicles/day (2 ways)

Speed limit 100km/h

Cross section 2 lane 2 way highway in fill, 3.5m lanes, 2.5m shoulders, 1.5m verge, 4:1 batters, 4m wide (i.e. 1m high)

Hazard Trees at 1.6m, 2.0m and 3.0m offset from back of verge on inside of curve (refer diagram)

Step 1: Identify hazards warranting protection Determine clear zone width (VRS Part 6 - Section 4.0) Speed limit = 100 km/h, Operating Speed = 110 km/h (AGRD Part 3 - Section 3.0) One way traffic volume = 3,500 vehicles/day Basic clear zone width = 8m (VRS Part 6 – Figure V4.1)

4:1 fill batter slopes are considered partially recoverable where errant vehicles may travel further than on a flatter slope; Effective clear zone (ECZ) width (VRS Part 6 - Section 4.2.2.3)

For northbound traffic, 8m basic clear zone width extends over full width of batter. From VRS Part 6 - Figure V4.2, only half of the batter width can be included in the effective clear zone, so ECZ = 8 + 2 = 10m.

Figure 10: Effective clear zone

For southbound traffic, 1m of basic clear zone width extends over 4:1 batter. From VRS Part 6 - Figure V4.2, this clear zone width over the 4:1 batter is doubled, so ECZ = 7 + 2x1 = 9m.


• For northbound traffic, trees 1, 2 and 3 are within the ECZ, so protection is required. • For southbound traffic, only trees 2 and 3 are within the ECZ and require protection.

Step 2: Determine barrier length of redirection For northbound traffic, tree 1 will control the length of barrier required. For southbound traffic, tree 3 will control the length of barrier required.

Refer to Standard Drawing SD 3521 – Safety Barrier (Line B) Alignment Details

Northbound traffic Tree 1 is offset 6.5m from the edge of traffic lane. Assuming a trunk width of 0.5m, adopt protected width B = 7m.

WRSB offset from traffic lane (A):

• Desirable offset = 4m (see Section 4.2.2) • Minimum offset = 3m

At 4m offset from traffic lane, WRSB would be located on the 4:1 batter hinge point. This position is not acceptable, unless the system proposed has been successfully crash tested in this configuration (refer Section 4.2.4(b)). If the desirable offset is not possible, then WRSB should be located as far as possible from the traffic lane. As some verge width is likely to be required behind the barrier to meet design deflection requirements, try WRSB at 3m offset from traffic lane.

From Table B of SD 3521, at 110 km/h with A = 3.0m and B = 7m, Z = 65m.

AADT = 3,500 v/d, therefore Z = 55m (65 x 0.81)

Southbound traffic Tree 3 is offset 9m from the centreline of the road, which is the edge of the closest southbound traffic lane.

From Table B of SD 3521, at 110km/h with A = 6.5m and B = 9m, Z = 35m

AADT = 3,500 v/d, therefore Z = 30m (35 x 0.81)

Total length Total Length of Redirection:

= Z for Tree 1 + Distance between Trees 1 & 3 + Z for Tree 3.

= 55 + 120 + 30

= 205m

Barrier length:

= 205 + terminals (12m where not specified)

= 229m

Step 3: Determine barrier location and configuration Having determined a length of redirection for the barrier at an offset of 3m from the traffic lane, the next step is to confirm that this offset is appropriate, and then determine the required post and anchor spacing. The aim of the design should be to maximise the offset of the barrier from the traffic lane and maximise the post and anchor spacing.

For the 3m offset from the traffic lane to be appropriate, the offsets required to hazards as described in Sections 4.2.3 and 4.2.4 respectively must be met.

Offsets to hazard (see Section 4.2.4) The required offset between WRSB and hazard will be either “working width” for case 1 hazards or “dynamic deflection” for case 2 hazards. In this instance Tree 2 will act as a case 1 hazard and the batter will act as a case 2 hazard.

Tree 2 – Case 1 hazard Given WRSB offset is 2.6m from Tree 2, working backwards to find allowable Dstd;


Dmax = Dstd x Fl x Fc Dmax = 2.6m,

Fl = 1.0, from Appendix B, Table 4, for barrier length

= 229m,

Fc = 1.2, from Appendix B, Table 5, for 700m radius curve where convex side impacts may occur.

2.6 = Dstd x 1.0 x 1.2,

Dstd = 2.17m

From Appendix B, Table 3, a “working width” standard for design deflection with a reduced post spacing is required to achieve Dstd = 2.17m (1.9m).

Fill Batter – Case 2 hazard Given WRSB offset is 1 m from top of batter, the desirable verge width should be Dmax. working backwards to find allowable Dstd;

Dmax = Dstd x Fl x Fc 1.0 = Dstd x 1.0 x 1.2,

Dstd = 0.84m


From Appendix B, Table 3, a design deflection with either post spacing will not achieve Dstd = 0.84m. If widening of the verge is not practicable, then the minimum verge width required can be Vmin.

Vmin = Dmax – 1.3m (see 4.2.4(b)) 1.0m = Dmax – 1.3;

Dmax = 2.3m

Dmax = Dstd x Fl x Fc 2.3m = Dstd x 1.0 x 1.2,

Dstd = 1.91m

From Appendix B, Table 3, a “dynamic deflection” standard for design deflection with a standard post spacing is required to achieve Dstd = 1.91m (1.8m).

Minimum constraint for the site is Tree 2, which requires reduced post spacing. Since the adoption of the larger post spacing would be preferable, and can be achieved for the case 2 batter hazard, it is possible to use a standard post spacing with a minimum length of reduced post spacing.

From Section 4.3.3, the minimum length of reduced post spacing is 30m. As the hazard can be approached from only one direction, the reduced post spacing should extend for 20m on the approach side of the tree, and 20m on the departure.

Having determined that WRSB can be located at 3m offset from the traffic lane and meets the clearance requirements to hazards and batters, confirmation is required from the barrier supplier that adequate support is available for the posts and anchors at this particular site.

Step 4 End treatments and runout areas Both ends of the WRSB require crash tested terminals regardless if they are approach or departure. See Section 4.3.6.

Alternative treatments for the termination of WRSB are shown on standard drawing SD 3573. The highest standard treatment that can be accommodated at the site should be adopted. This may require earthworks to widen the verge in the vicinity of the terminal.

Treatments for the southern and northern terminals at this site are shown in Figures D1 and D2. The basis for these layouts is as follows:

Northern terminal – Figure D1 The desirable treatment would include a widening of the verge to provide a flat runout area behind the WRSB terminal and a flaring of the WRSB on a 200m radius curve prior to the terminal to offset the point of redirection a further 2m from the traffic lane and direct the terminal away from approaching traffic.

However, in this case, as the length of redirection is relatively short at 30m, the adoption of this treatment, together with the 20m shortening of the length of redirection would result in Tree No.3 being located within 10m of the start of the terminal flaring (refer SD 3573), which is unacceptable.

This problem could be avoided by forgoing the shortening of the length of redirection available from offsetting the point of redirection by 2m, but an acceptable alternative would be to adopt a smaller flare, in this case a 1m offset, which still provides some shortening of the length of redirection without compromising the hazard free zone required beyond the terminal. This is the treatment shown in Figure D1 below.

Southern terminal – Figure D2 At this site there are no constraints preventing the adoption of the desirable flared terminal treatment shown on SD 3573. This treatment should be adopted where possible.

Straight terminal option – verge widening requirements

If the assessment of site constraints concluded that flared terminal treatments were not practicable then a straight terminal treatment as per SD 3573 could be adopted. Note that even the minimum straight terminal treatment shown in SD 3573 would require some verge widening in this case. This verge widening is important given the potential for WRSB terminals to destabilise vehicles in end on impacts.


Appendix E - Stopping refuge bay layout Figure E1 below shows the preferred layout for stopping refuge bays within WRSB installations more than 500m long at offsets to traffic lanes of less than 4.0m.


Appendix F – Continuous safety barrier summary sheet

The following summary is unchanged from ‘RDN 06-15 – Continuous safety barrier for High Speed Roads (v1.0)’ and may be outdated.

While RDN 06-15 has been withdrawn, this list may be useful to some designers. This list does not take precedence over any other guidance, it merely acts as a summary.

• Continuous safety barrier should be treated like a longitudinal component of the road, with an intent to shield all roadside elements as effectively as possible; including all hazards within the ‘area of interest’ (not only within the clear zone), areas of flat terrain that may cause roll-over, and cut embankments irrespective of grade

• Attractive roadsides strengthen a sense of place and give travellers a more rewarding experience. Continuous lengths of similar barrier types and designs are desirable to draw focus on the natural landscape

• WRSB and flexible GF systems should be used where possible, as these barrier types have the lowest impact severity and greatest potential to reduce occupant injury.

• Table 1 provides common brownfield (retrofit) scenarios and the preferred safety barrier type.

• MASH products should be installed where possible to future proof the serviceability of the asset.

• Every effort should be made to achieve the desirable offset of 4.0-6.0 metres as it allows broken down vehicles to pull over clear of traffic lanes and provides space for maintenance vehicles. An offset closest to this range is preferred.

• Greater offsets allowed in certain locations, e.g. ESBs

• Median barrier offsets between 2.0m-3.0m should be avoided to discourage vehicles from pulling over into a narrow shoulder.

• Where a divided carriageway has two or less lanes in one direction, median barrier offsets may be less than minimum when a barrier offset 3.0m or greater is provided on the verge.

• Projects should consider mitigation measures for lengths of reduced barrier offset; speed reduction, localised pull over opportunities, increased sight lines, advisory signing

• Safety barrier should be overlapped to maintain a continuous barrier system.

• Maximum safety barrier length is typically 1km for WRSB, longer lengths may be used where the risk of nuisance impacts is low; desirable offset, straight alignment, ATLM. Maximum length of Flexible GF not defined.

• Provision for stopping considers non-discretionary and elective stopping to allow safe pull over in the event of an emergency or voluntary stop, e.g. Emergency Stopping Bay.

• Bays are provided at least every 1km-4km. The precise frequency should be determined with consideration of; a route plan, minimising the cost of earthworks required, providing adequate sightlines, and targeting high risk stopping sites.

• Help Phone Bays can be removed unless poor cellular coverage is identified.

• Provide adequate access for emergency services where possible. Contact local service to agree/determine locations of access points.

• Traditional length of need process not critical; rather commence the barrier at the earliest location possible and identify potential unprotected areas.

• Run-out area requirements to be provided at critical and appropriate locations along the proposal.

• Barrier must be offset or flared to 3.0m near a side road or property access to provide sight lines. Otherwise, individual risk assessment is required.

• Barriers offset to hinge point (6:1 or flatter) should be more than dynamic deflection. Where this requires considerable earthworks, absolute minimum is 1.0m for WRSB and 0.5m for flexible and semi-rigid GF.

• Replace all MELT, BCTA, BCTB & FLEXFENCE Standard terminals with a G.R.E.A.T, T.T. or Flex fence TL-3 terminal.

• Upgrade existing guard fence (<686mm) using Abraham Blocks or Replace with a more forgiving system.

• Consider raising the height of existing guard fence (<720mm) using Abraham Blocks or consider replacing with a more forgiving system.

• Consider replacing Sentryline II (releasing) terminals with a Sentryline III (non-releasing) terminal when the barrier offset is < 3m and barrier length is 500m and greater.

• Assess the performance requirements of existing 3-rope WRSB systems and upgrade where cost effective;

• System specific designs may be considered when the proprietary product is known

• Provide flexible GF and rub-rail on high risk motorcycle routes; crash history, high volume, tight curves.

• Fauna crossings to be considered in consultation with Urban Design.

• Medians less than 10m, single barrier run can be used. Medians greater than 10m; two barrier runs required unless the median is free of hazards, the batter is 10:1 and a second barrier run is catered for in the future.

• Entry and exit ramps should be treated, however, the main carriageway must take priority. Must allow for vehicles to pass a broken-down vehicle.

• Speed management treatments (e.g. speed limits and speed calming) may be needed through townships or on roads with high frequency of side roads, access points and median access

• Unprotected areas must be assessed and treated where possible. Exposed hazards within the clear zone must be removed to eliminate the risk of injury (preferred), relocated behind the barrier, or relocated beyond the clear zone (least preferred) as per AGRD Part 6, Section 4.

• Sealing in front of barrier not required unless considered a local high-risk location.

• Audio tactile line marking to be installed in-front of barrier to mitigate the likelihood of impact.

• Road Safety Audit and Safe System Assessment to be conducted at various stages of the project.

• Safety barrier maintenance strips only considered were treatment offers whole-of-life benefit.

• Maintenance and service authority access points to be strategically located to support maintenance activities.


Appendix G – Typical barrier drawings

Typical barrier drawings have been provided from ‘RDN 06-15 – Continuous safety barrier for high-speed roads (v1.0)’. While these drawings are not a standard or minimum requirement, they may be adopted by projects when the layout is suitable for site.

Please contact [email protected] if you have additional drawings that may be included.

Number Page Description Comments

782001 45 Formation widening – Guard fence and WRSB Distance between barrier and hinge point shown is a minimum and does not cater for dynamic deflection (desirable).

782002 46 Cut embankment – No Kerb Distance between barrier and cut batter is 2.5m minimum to allow for typical maintenance practices.

782003 47 Cut embankment – With Kerb

782004 48 Table drain relocation (FILL) 782005 49 Table drain relocation (CUT) Need to consider maintenance practices.

782006 50 Emergency services – Median Barrier Access - 90 Degrees PoN overlap

782007 51 Maintenance access – 10 Degrees PoN overlap

To be used after consideration of 90 and 25-degree PoN overlap. Refer Supplement to AGRD Part 6, Section V5.4.3


To be used after consideration of 90-degree PoN overlap. Refer Supplement to AGRD Part 6, Section V5.4.3


Refer Supplement to AGRD Part 6, Section V5.4.3

782010 54 Side road access – Barrier layout

782011 55 Stopping refuge bay - Wire rope safety barrier

782012 56 Access on bridge departure – 90 Degrees PoN overlap

782013 57 Emergency services – Vehicle Median Turn Area

Sight lines are critical. Likely earthworks to achieve barrier offsets and maximum barrier length.

782014 58 Combined - Refuge Bay & Median Access Refer Supplement to AGRD Part 6, Section 5.4. 782015 59 WRSB – Departure overlap detail (no access)

782016 60 GF – Departure overlap detail (no access)

782017 61 WRSB – Approach overlap detail (no access)

782018 62 GF – Approach overlap detail (no access)

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0.5m MIN

HINGE POINT

SLOPE

2:1 (H:V) MAX

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. . .

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FORMATION WIDENING

(EXISTING)

4m DESIRED

3m MIN

EXISTINGWIDEN

TRAFFIC LANESHOULDER

(EXISTING)

EXISTING

EXISTING CONDITION

10:1 (MAX)

1.0m MIN

HINGE POINT

TRAFFIC LANESHOULDER

SLOPE

2:1 (H:V) MAX

FLEXIBLE W-BEAMWITH GUARD FENCE / FORMATION WIDENING

WITH WRSBFORMATION WIDENING

4m DESIRED

3m MIN

EXISTINGWIDEN

10:1 (MAX)

GUARD FENCE / WIRE ROPE

SHOULDER TRAFFIC LANEZONEDEFLECTION

ZONEDEFLECTION

SAFE SYSTEM BARRIER

782001

(REFER TO RDN 06-08)1.65m FOR FLEXIBLE W-BEAM

1.00m FOR GUARD FENCEAREA TO BE CLEAR OF HAZARDS

TYPE-B FILL

TYPE-B FILL

(REFER TO APPENDIX A RDN 06-02)VARIES DUE TO LENGTH CORRECTION FACTORS

1.5m TO 2.1mAREA TO BE CLEAR OF HAZARDS

ISSUE DATEAPP'D AMENDMENT

GENERAL NOTES

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CUT EMBANKMENT

NO KERB

SHOULDER

ZONEDEFLECTION

SHOULDER

ZONEDEFLECTION

(REFER TO APPENDIX A RDN 06-02)1.5m TO 1.8m

AREA TO BE CLEAR OF HAZARDS

1.65m FOR FLEXIBLE W-BEAM1.00m FOR GUARD FENCE


2.5m[1]

2.5m[1]

W-BEAMGUARD FENCE / FLEXIBLE

CUT EMBANKMENT

WITH WRSBCUT EMBANKMENT

SAFE SYSTEM BARRIER

782002

EMBANKMENT [1]

2.5m AWAY FROM CUT

BARRIER TO BE INSTALLED

ZONE.

EMBANKMENT IS OUTSIDE THE DEFLECTION

BARRIER, OTHERWISE ENSURE THE

MAINTENANCE VEHILCE ACCESS BEHIND THE

EMBANKMENT WHERE POSSIBLE TO ALLOW FOR

OFFSET THE BARRIER 2.5m FROM THE [1]


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. . .

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CUT EMBANKMENT

WITH KERB

SHOULDER

ZONEDEFLECTION

SHOULDER

ZONEDEFLECTION

FROM CUT EMBANKMENT

INSTALLED 2.5m AWAY

BARRIER TO BE

(REFER TO APPENDIX A RDN 06-02)1.5m TO 1.8m


1.65m FOR FLEXIBLE W-BEAM1.00m FOR GUARD FENCE


W-BEAMGUARD FENCE / FLEXIBLE

CUT EMBANKMENT

WITH WRSBCUT EMBANKMENT

1:6 (MAX.)1:10 (DESIRABLE)

1:6 (MAX.)1:10 (DESIRABLE)

SAFE SYSTEM BARRIER

782003ISSUE DATEAPP'D AMENDMENT

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A

B

C

D

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. . .

. .SAFE BARRIER SYSTEMS

OFFSET

AS SPECIFIED

TRAFFIC LANE

SAFETY BARRIER

PROFILE (VARIES)

EXISTING SURFACE

TYPICAL SECTION - TABLE DRAIN RELOCATION (FILL)

TABLE DRAIN RELOCATION

(FILL)

DEFLECTION ZONE

TO OUTSIDE OF THE

RELOCATE TABLE DRAIN

DEFLECTION ZONE

RDN 06-08 FOR W-BEAM

RDN 06-02 FOR WRSB

REFER TO

WITH TYPE-B FILL

BACKFILL TABLE DRAIN

782004ISSUE DATEAPP'D AMENDMENT

GENERAL NOTES

A

B

C

D

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TABLE DRAIN RELOCATION

(VARIES)

EXISTING SURFACE

SAFETY BARRIER

WITHIN DEFLECTION OF

BATTER FACE LOCATED

OR FLATTER WHEN

CUT BATTER TO 6:1 (H:V)

STRIP

MAINTENANCE

CONCRETE

OFFSET

AS SPECIFIED

TRAFFIC LANE

SAFETY BARRIER

TYPICAL SECTION - TABLE DRAIN RELOCATION (CUT)

(CUT)

SAFE SYSTEM BARRIER

782005

THE DEFLECTION

DRAIN TO OUTSIDE

RELOCATE TABLE

DEFLECTION ZONE

RDN 06-08 FOR W-BEAM

RDN 06-02 FOR WRSB

REFER TO

WITH TYPE-B FILL

BACKFILL TABLE DRAIN


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SHOULDER

TRAFFIC LANE

TRAFFIC LANE

DIRECTION OF TRAFFIC


10.0m

(ANGLE AS NOTED)

POINT OF NEED OVERLAP

10.0m10.0m

4.0

m

OR FLATTER

1:6 MAXIMUM

SHOULDER IS LESS THAN 3m.

IMPLEMENTED WHERE

TRAFFIC MANAGEMENT TO BE

WHERE MAINTENANCE ACCESS IS TO BE PROVIDED ON AN EXISTING SYSTEM, THE EXISTING OFFSET SHOULD BE MAINTAINED.OFFSET OF 4.0m IS DESIRED FOR NEW INSTALLATIONS (3.0m MIN).

MINIMUM4.0m

MEDIAN BARRIER ACCESS

(REFER TO RDN 06-04)

END TERMINAL

VICROADS APPROVED


END TERMINAL

VICROADS APPROVED

CONCRETE)

(OR APPROVED ALTERNATIVE ASPHALT /

10:1 OR FLATTER

200mm CRUSHED ROCK HARD STAND AREA

SYSTEM

SAFETY BARRIER

PROPOSED

SAFE SYSTEM BARRIER

782006

90°

MAINTENANCE VEHICLE ACCESS INTO THE MEDIAN.

TRAFFIC MANAGEMENT SHOULD BE IMPLEMENTED TO ALLOW

WHERE THE SHOULDER IN THE FAST LANE IS LESS THAN 3m, 2.

ACHIEVE THE ANGLE OF PON OVERLAP AS NOTED ON THE PLAN.

THE TWO BARRIER SYSTEMS. FURTHERMORE, IT IS DESIRABLE TO

A MINIMUM, ENSURE THAT A GAP OF 4.0m IS PROVIDED BETWEEN

WHERE SITE CONDITIONS DIFFER FROM THIS TYPICAL LAYOUT, AS 1.

NOTES

EMERGENCY SERVICES OPERATION & MAINTENANCE ACCESS


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SHOULDER

SHOULDER

TRAFFIC LANE

TRAFFIC LANE

28.2m

4.0m2.0m



SAFETY BARRIER

WIRE ROPE

SAFETY BARRIER

WIRE ROPE

CURVED LENGTH OF 200R

WRSB TERMINAL

NOTE 1)(REFER TO4.9m

BASED ON A 12m WRSB TERMINAL.1.

NOTES

TERMINAL

WRSB

15.0m

SPECIFIEDOFFSET AS

SPECIFIEDOFFSET AS

OVERLAP AT 10°

POINT OF NEED

36.8m

48.8m (REFER TO NOTE 1)

MAINTENANCE ACCESS

10 DEGREE POINT OF NEED OVERLAP

SAFE SYSTEM BARRIER

782007

ASPHALT / CONCRETE)

(OR APPROVED ALTERNATIVE

10:1 OR FLATTER

STAND AREA

200mm CRUSHED ROCK HARD

HARD STAND


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SHOULDER

SHOULDER

TRAFFIC LANE

TRAFFIC LANE

28.2m

4.0m2.0m




WRSB TERMINAL



NOTES

TERMINAL

WRSB

15.0m

SPECIFIEDOFFSET AS

SPECIFIEDOFFSET AS

OVERLAP AT 25°

POINT OF NEED

45.5m


SAFE SYSTEM BARRIER

782008

WRSB

(WRSB)

SAFETY BARRIER

WIRE ROPE

25°

ASPHALT / CONCRETE)

(OR APPROVED ALTERNATIVE

10:1 OR FLATTER

STAND AREA

200mm CRUSHED ROCK HARD

HARD STAND



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SHOULDER

SHOULDER

TRAFFIC LANE

TRAFFIC LANE

28.2m

55.1m

4.0m2.0m




WRSB TERMINAL




NOTES

TERMINAL

WRSB

OVERLAP AT 90°

POINT OF NEED

15.0m

SPECIFIEDOFFSET AS

SPECIFIEDOFFSET AS

SAFE SYSTEM BARRIER

782009

CONCRETE)

ALTERNATIVE ASPHALT /

(OR APPROVED

10:1 OR FLATTER

HARD STAND AREA

200mm CRUSHED ROCK

HARD STAND


(WRSB)

SAFETY BARRIER

WIRE ROPE

WRSB


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SHOULDER

SHOULDER

TRAFFIC LANE

TRAFFIC LANE



SPECIFIEDOFFSET AS

SID

E

RO

AD /

ACCESS

SPECIFIEDOFFSET AS

18.0m MIN

SHOULDER

SHOULDER

TRAFFIC LANE

TRAFFIC LANE



SPECIFIEDOFFSET AS

2.0 (MAX)

1.0

1.5

W

Y

24.4

(m)

'W'

TERMINAL OFFSET

(m)

'Y'

LONGITUDINAL LENGTH

28.2

20.0

SID

E

RO

AD /

ACCESS

SPECIFIEDOFFSET AS

SAFETY BARRIER

SAFETY BARRIER

FLARED TERMINAL

TERMINAL

STRAIGHT

CHANNEL

KERB AND

PROPERTY / SIDE ROAD ACCESS

BARRIER LAYOUT

SAFE SYSTEM BARRIER

782010

CURVED LENGTH OF 200R FOR WRSBOR 40R FOR GUARD FENCE / FLEXIBLE W-BEAM

PRACTICABLE.

TO THE SIDE ROAD / ACCESS AS

SAFETY BARRIER SHOULD EXTEND AS CLOSE 1.

NOTES

REFER TO VICROADS SD 3573


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PON OVERLAP

SHOULDER

SHOULDER

SURFACE.

LOCATION IS WITHIN A DRIVEABLE

THAT THE MAINTENANCE ACCESS

BARRIER TO BE EXTENDED TO ENSURE

ACCESS ON BRIDGE DEPARTURE

BARRIER

EXISTING BRIDGE

DEPARTURE SIDE OF

DETAILS.

BRIDGE CONNECTION

REFER SD 4048 FOR

BRIDGE BARRIER.

GUARD FENCE AND

CONNECTION BETWEEN

ENSURE SATISFACTORY

DIRECTION OF TRAVEL

DIRECTION OF TRAVEL

SAFE SYSTEM BARRIER

782012

10.0m 10.0m

4.0

10:1 OR FLATTER

HARD STAND AREA

200mm CRUSHED ROCK

SAFETY BARRIEROR FLATTER

1:6 MAXIMUM

TERMINAL

TERMINAL SPECIFIEDOFFSET AS


DRIVEABLE (IE 6:1)

WHERE THE SURFACE IS

BARRIER TO A LOCATION

EXTEND EXISTING BRIDGE

SEE ABOVE FOR BRIDGE BARRIER EXTENSION DETAILS

5000 5000

7 SPACES AT 1000 SPACINGS = 7000500 = 25005 SPACES AT

25002500 2500 2000 2000

TRAILING TERMINAL

2500

EXTEND AS REQUIRED

500

10000


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PREFERRED LAYOUT FOR STOPPING REFUGE BAY

LAYOUT FOR STOPPING REFUGE BAY

WIRE ROPE SAFETY BARRIER

(m)

'A'

TRAFFIC LANE

WRSB OFFSET TO

(m)

'B'

ARC LENGTH

100 R CURVE

1 20

2 15

3 10

100R*

100R* 100R*

100R*

20m55m20m

SAFE SYSTEM BARRIER

782011

TRAFFIC

ON THE CONVEX SIDE OF THE CURVE ARE POSSIBLE.

5m OF 100m RADIUS CURVE SECTIONS WHERE IMPACTS

UNYIELDING HAZARDS SHOULD NOT BE LOCATED WITHIN 3.

AREAS.

REDUCED POST SPACINGS WILL BE REQUIRED IN THESE 2.

BAY.

INSTANCE ONLY TO LIMIT THE SIZE OF THE REFUGE

100m RADIUS CURVES ARE ACCEPTABLE IN THIS 1.

*NOTES:

5m MIN

REFER TO APPENDIX E RDN 06-02

TRAFFIC


GENERAL NOTES

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NTS

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0

0

. . .

. . .

.

-

. . .

TRAFFICWORKS

MAY'17

MAY'17

VICROADS

-

-

. . .

. .

SHOULDER

TRAFFIC LANE

TRAFFIC LANE



SPECIFIEDOFFSET AS

TO THE SIDE ROAD / ACCESS AS PRACTICABLE.

SAFETY BARRIER SHOULD EXTEND AS CLOSE 1.

NOTES

SHOULDER

TRAFFIC LANE

TRAFFIC LANE

2.0 (MAX)

1.0

1.5

W

Y

24.4

(m)

'W'

TERMINAL OFFSET

(m)

'Y'

LONGITUDINAL LENGTH

28.2

20.0

SPECIFIEDOFFSET AS

FLARED TERMINAL

SPECIFIEDOFFSET ASSPECIFIEDOFFSET AS

6.0



WFLARED TERMINAL

CONSTRAINTSTO SIGHT DISTANCEDISTANCE SUBJECT

SAFE SYSTEM BARRIER

782013

4A.

BE REVIEWED IN CONJUNCTION WITH AGRD PART

SAFE INTERSECTION SIGHT DISTANCE (SISD) SHOULD

SATISFY SIGHT LINE REQUIREMENTS, HOWEVER,

GENERALLY A 3.0m BARRIER OFFSET WOULD

VEHICLE MEDIAN TURN AREA

EMERGENCY SERVICES / VICROADS

(WRSB)

SAFETY BARRIER

WIRE ROPE


GENERAL NOTES

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SCALE OF METRES

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. . .

. . .

.

-

. . .

TRAFFICWORKS

MAY'17

MAY'17

VICROADS

-

-

. . .

. .

PREFERRED LAYOUT FOR STOPPING REFUGE BAY

100R*

100R*12.0 12.0



SHOULDER

SHOULDER

OVERLAP

POINT OF NEED

4.0

12.0 12.0 55.0 40.0

COMBINED REFUGE BAY & EMERGENCY ACCESS


ON THE CONVEX SIDE OF THE CURVE ARE POSSIBLE.

5m OF 100m RADIUS CURVE SECTIONS WHERE IMPACTS

UNYIELDING HAZARDS SHOULD NOT BE LOCATED WITHIN 3.

AREAS.

REDUCED POST SPACINGS WILL BE REQUIRED IN THESE 2.

SIZE OF THE REFUGE BAY.

POST SPACINGS) IN THIS INSTANCE ONLY TO LIMIT THE

100m RADIUS CURVES ARE ACCEPTABLE (WITH REDUCED 1.

*NOTES:

OVERLAP

POINT OF NEED

SHOULDER



SHOULDER

2.0


CONSTRAINED)

(WHERE DEFLECTION MAY BE

REDUCED PULL OUT AREA

ALTERNATIVE LAYOUT FOR STOPPING REFUGE BAY

4.0m MIN

SAFE SYSTEM BARRIER

782014

ACCESS OPENING

ENSURE MINIMUM 4.0m


GENERAL NOTES

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SCALE OF METRES

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. . .

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TRAFFICWORKS

MAY'17

MAY'17

VICROADS

-

-

. . .

. .

TRAFFIC

1

TRAFFIC

CONDITIONS FOR USE

NOTES

(REFER TO NOTE 3 & 4)APPROACH OFFSET

(REFER TO NOTE 3)DEPARTURE OFFSET

APPROACH END TERMINALALONG THE LENGTH OF THE

MAINTAIN CLEARANCE


TRANSITION LENGTH

LENGTHCURVE

(REFER TO NOTE 1)RADIUS


(REFER TO NOTE 5)

POINT OF NEED

TERMINAL

WIRE ROPE END

TERMINAL

WIRE ROPE END

DESIGN SPEED

110

100

90

80

30:1

26:1

24:1

21:1

15:1

14:1

12:1

11:1

FLARE RATE

LINE OFFSETWITHIN SHY

LINE OFFSETOUTSIDE SHY

2.8

2.4

2.2

2.0

(m)OFFSET

SHY LINE

DEPARTURE OVERLAP TREATMENT


8 (MAX)

(REFER TO TABLE 1)BARRIER FLARE RATE

TYPICAL LAYOUTS

TRANSITION BARRIER TO SAME OFFSET2.INSTALL OVERLAP BEHIND BARRIER1.

DESIGN PHILOSOPHY

INCREASED)NO TRANSITION (OFFSET TO TRAFFIC LANE IS 2.INSTALL OVERLAP BEHIND BARRIER1.

(OFFSET TO TRAFFIC LANE IS INCREASED)NO TRANSISTION CLOSER TO THE TRAFFIC LANE 2.INSTALL OVERLAP BEHIND BARRIER1.

TRANSITION BARRIER TO DESIRED OFFSET.3.BARRIERENSURE OVERLAP SYSTEM IS BEHIND APPROACH 2.REMOVE EXISTING TERMINAL AND REALIGN BARRIER1.

EXISTING BARRIER ON THE APPROACH SIDE.2.TYPICAL SETUP FOR DIVIDED CARRIAGEWAY.1.

(REFER TO NOTE 6)1.5m - 2.1mCLEARANCE

NOTES

TABLE 1

BARRIER. REFER TO AGRD PART 6 FOR REQUIRED FLARE RATES OF SAFETY

EXISTING OFFSET)TRANSITION TO PROPOSED OFFSET (3.0m DESIRED - MAINTAIN 4.DETERMINE PROPOSED OFFSET FROM THE TRAFFIC LANE3.DETERMINE REQUIRED CLEARANCE BETWEEN BARRIER SYSTEMS2.INSTALL OVERLAP BEHIND EXISTING BARRIER1.

PON

PON

PON

PON

PON

SAFE SYSTEM BARRIER

DEPARTURE OVERLAP DETAIL

782015

MINIMISED AND NOT EXPOSED TO THE TRAFFIC (REFER TO SD 4071). MAXIMUM FLARE RATE OF 8:1 WHERE TRANSITION IS TO BE

RDN 06-02).NOT IMPACTED BY THE BARRIER BEHIND IT (REFER TO APPENDIX AENSURES THAT THE PERFORMANCE OF THE BARRIER IN FRONT IS CLEARANCE OF THE OVERLAPS BETWEEN THE TWO SYSTEMS; THIS THE DEFLECTION OF THE APPROACH BARRIER WILL DETERMINE THE 6.ALONG THE ALIGNMENT.THE TWO BARRIER SYSTEMS TO ENSURE CONTINUOUS PROTECTION IT IS DESIRABLE TO HAVE THE POINT OF NEED OVERLAP BETWEEN 5.SHOULD BE SOUGHT FROM THE SUPERINTENDENT.WHERE THE PROPOSED OFFSET IS LESS THAN 3.0m, APPROVAL 4.IS 4.0m (3.0m MINIMUM).THE DESIRABLE OFFSET OF THE BARRIER FROM THE TRAFFIC LANE 3.SHOULD BE MAINTAINED TO KEEP A CONSISTENT BARRIER LINE.BARRIER SYSTEM, THE EXISTING OFFSET TO THE TRAFFIC LANE WHERE THE OVERLAP IS TO BE RETROFITTED ONTO AN EXISTING 2.FIGURE, E1 NOTE 1)RADIUS OF 100m MAY BE CONSIDERED (REFER TO RDN 06-02, TO BE USED. WHERE TRANSITION LENGTH IS TO BE MINIMISED, A DESIRABLE RADIUS OF 200m FOR WIRE ROPE SAFETY BARRIER IS 1.


GENERAL NOTES

A

B

C

D

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DESIGNED

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. . .

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. . .

TRAFFICWORKS

MAY'17

MAY'17

VICROADS

-

-

. . .

. .

TRAFFIC

1

TRAFFIC

CONDITIONS FOR USE




MAINTAIN CLEARANCE

TRANSITION LENGTH

LENGTHCURVE



8 (MAX)

(REFER TO TABLE 1)BARRIER FLARE RATE

TYPICAL LAYOUTS

TRANSITION BARRIER TO SAME OFFSET2.INSTALL OVERLAP BEHIND BARRIER1.

INCREASED)NO TRANSITION (OFFSET TO TRAFFIC LANE IS 2.INSTALL OVERLAP BEHIND BARRIER1.

(OFFSET TO TRAFFIC LANE IS DECREASED)NO TRANSISTION CLOSER TO THE TRAFFIC LANE 2.INSTALL OVERLAP BEHIND BARRIER1.

TERMINAL

TRAILING

GUARD FENCE

(REFER TO NOTE 6)1.65m FOR SEMI FLEXIBLE W-BEAM

1.0m FOR GUARD FENCECLEARANCE


END TERMINAL

VICROADS APPROVED

(REFER TO NOTE 5)

THE TWO TERMINALS

POINT OF NEED OVERLAP BETWEEN


NOTES

DESIGN SPEED

110

100

90

80

30:1

26:1

24:1

21:1

20:1

18:1

16:1

14:1

FLARE RATE



2.8

2.4

2.2

2.0

(m)OFFSET

SHY LINE

DESIGN PHILOSOPHY



NOTES

TABLE 1



GUARD FENCE / FLEXIBLE W-BEAM

SAFE SYSTEM BARRIER

DEPARTURE OVERLAP DETAIL

782016

NOT IMPACTED BY THE BARRIER BEHIND IT.ENSURES THAT THE PERFORMANCE OF THE BARRIER IN FRONT IS CLEARANCE OF THE OVERLAPS BETWEEN THE TWO SYSTEMS; THIS THE DEFLECTION OF THE APPROACH BARRIER WILL DETERMINE THE 6.PROTECTION ALONG THE ALIGNMENT.NEED OF THE TWO BARRIER SYSTEMS TO ENSURE CONTINUOUS IT IS DESIRABLE TO HAVE A 90° OVERLAP FOR THE POINT OF 5.SHOULD BE SOUGHT FROM THE SUPERINTENDENT.WHERE THE PROPOSED OFFSET IS LESS THAN 3.0m, APPROVAL 4.IS 4.0m (3.0m MINIMUM).THE DESIRABLE OFFSET OF THE BARRIER FROM THE TRAFFIC LANE 3.SHOULD BE MAINTAINED TO KEEP A CONSISTENT BARRIER LINE.BARRIER SYSTEM, THE EXISTING OFFSET TO THE TRAFFIC LANE WHERE THE OVERLAP IS TO BE RETROFITTED ONTO AN EXISTING 2.RADIUS OR TO MANUFACTURER REQUIREMENTS.GUARD FENCE / FLEXIBLE W-BEAM TO BE INSTALLED ON A 40m 1.


GENERAL NOTES

A

B

C

D

E


DESIGNED

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VER

SCALE OF METRES

13-Jun-17

3:5

0:19 P

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166030-FLP-16.d

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APPROVED

PTY LTD

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WORKING RELEASE

NTS

AXXX

0

0

. . .

. . .

.

-

. . .

TRAFFICWORKS

MAY'17

MAY'17

VICROADS

-

-

. . .

. .

TYPICAL LAYOUTS


TRAFFIC

1

TRAFFIC




MAINTAIN CLEARANCE

TRANSITION LENGTH

LENGTHCURVE



(REFER TO NOTE 5)

POINT OF NEED



8 (MAX)(REFER TO TABLE 1)BARRIER FLARE RATE

TERMINAL

WIRE ROPE END

CONDITIONS FOR USE

EXISTING BARRIER ON THE APPROACH SIDE.2.SHOULD BE ONLY USED IN DIVIDED CARRIAGEWAY.1.

(REFER TO NOTE 5)

POINT OF NEED

TERMINAL

WIRE ROPE END

APPROPRIATE CLEARANCE.BARRIER TO BEHIND THE APPROACH BARRIER WITH REMOVE EXISTING TERMINAL AND REALIGN THE 2.INSTALL APPROACH BARRIER TO DESIRED OFFSET.1.

TRANSITION AS REQUIRED.2.OFFSET IN FRONT OF THE EXSITING BARRIER.INSTALL THE APPROACH BARRIER TO THE DESIRED 1.

(REFER TO NOTE 6)1.5m - 2.1mCLEARANCE

NOTES

DESIGN SPEED

110

100

90

80

30:1

26:1

24:1

21:1

15:1

14:1

12:1

11:1

FLARE RATE



2.8

2.4

2.2

2.0

(m)OFFSET

SHY LINE

4071). MINIMISED AND THE NOT EXPOSED TO THE TRAFFIC (REFER TO SD MAXIMUM FLARE RATE OF 8:1 WHERE TRANSITION IS TO BE

DESIGN PHILOSOPHY

NOTES

TABLE 1



PON

PON

PON

SAFE SYSTEM BARRIER

APPROACH OVERLAP DETAIL

782017

RDN 06-02).NOT IMPACTED BY THE BARRIER BEHIND IT (REFER TO APPENDIX AENSURES THAT THE PERFORMANCE OF THE BARRIER IN FRONT IS CLEARANCE OF THE OVERLAPS BETWEEN THE TWO SYSTEMS; THIS THE DEFLECTION OF THE APPROACH BARRIER WILL DETERMINE THE 6.ALONG THE ALIGNMENT.THE TWO BARRIER SYSTEMS TO ENSURE CONTINUOUS PROTECTION IT IS DESIRABLE TO HAVE TO POINT OF NEED OVERLAP BETWEEN 5.SHOULD BE SOUGHT FROM THE SUPERINTENDENT.WHERE THE PROPOSED OFFSET IS LESS THAN 3.0m, APPROVAL 4.IS 4.0m (3.0m MINIMUM).THE DESIRABLE OFFSET OF THE BARRIER FROM THE TRAFFIC LANE 3.SHOULD BE MAINTAINED TO KEEP A CONSISTENT BARRIER LINE.BARRIER SYSTEM, THE EXISTING OFFSET TO THE TRAFFIC LANE WHERE THE OVERLAP IS TO BE RETROFITTED ONTO AN EXISTING 2.FIGURE, E1 NOTE 1)RADIUS OF 100m MAY BE CONSIDERED (REFER TO RDN 06-02, TO BE USED. WHERE TRANSITION LENGTH IS TO BE MINIMISED, A DESIRABLE RADIUS OF 200m FOR WIRE ROPE SAFETY BARRIER IS 1.

NO TRANSITION (OFFSET TO TRAFFIC LANE IS REDUCED)2.OFFSET IN FRONT OF THE EXSITING BARRIER.INSTALL THE APPROACH BARRIER TO THE DESIRED 1.


GENERAL NOTES

A

B

C

D

E


DESIGNED

HOR

VER

SCALE OF METRES

13-Jun-17

3:5

0:2

0 P

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166030-FLP-17.d

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FILE:

PROJ:

CAT:

APPROVED

PTY LTD

166030-FLP-17

WORKING RELEASE

NTS

AXXX

0

0

. . .

. . .

.

-

. . .

TRAFFICWORKS

MAY'17

MAY'17

VICROADS

-

-

. . .

. .

NOTES

DESIGN SPEED

110

100

90

80

30:1

26:1

24:1

21:1

20:1

18:1

16:1

14:1

FLARE RATE



2.8

2.4

2.2

2.0

(m)OFFSET

SHY LINE

TYPICAL LAYOUTS

DESIGN PHILOSOPHY

TRAFFIC

1

TRAFFIC




MAINTAIN CLEARANCE

TRANSITION LENGTH

LENGTHCURVE



8 (MAX)(REFER TO TABLE 1)BARRIER FLARE RATE

CONDITIONS FOR USE(REFER TO NOTE 5)

POINT OF NEED

APPROPRIATE CLEARANCE.BARRIER TO BEHIND THE APPROACH BARRIER WITH REMOVE EXISTING TERMINAL AND REALIGN THE 2.INSTALL APPROACH BARRIER TO DESIRED OFFSET.1.

TRANSITION AS REQUIRED.2.OFFSET IN FRONT OF THE EXSITING BARRIER.INSTALL THE APPROACH BARRIER TO THE DESIRED 1.

APPROACH OVERLAP TREATMENT




SAFE SYSTEM BARRIER



(REFER TO NOTE 5)

BETWEEN THE TWO TERMINALS



END TERMINAL

VICROADS APPROVED

(REFER TO NOTE 6)1.65m FOR SEMI FLEXIBLE W-BEAM

1.0m FOR GUARD FENCECLEARANCE

NOTES

TABLE 1


PON

PON

PON

APPROACH OVERLAP DETAIL

782018

NOT IMPACTED BY THE BARRIER BEHIND IT.ENSURES THAT THE PERFORMANCE OF THE BARRIER IN FRONT IS CLEARANCE OF THE OVERLAPS BETWEEN THE TWO SYSTEMS; THIS THE DEFLECTION OF THE APPROACH BARRIER WILL DETERMINE THE 6.PROTECTION ALONG THE ALIGNMENT.NEED OF THE TWO BARRIER SYSTEMS TO ENSURE CONTINUOUS IT IS DESIRABLE TO HAVE A 90° OVERLAP FOR THE POINT OF 5.SHOULD BE SOUGHT FROM THE SUPERINTENDENT.WHERE THE PROPOSED OFFSET IS LESS THAN 3.0m, APPROVAL 4.IS 4.0m (3.0m MINIMUM).THE DESIRABLE OFFSET OF THE BARRIER FROM THE TRAFFIC LANE 3.SHOULD BE MAINTAINED TO KEEP A CONSISTENT BARRIER LINE.BARRIER SYSTEM, THE EXISTING OFFSET TO THE TRAFFIC LANE WHERE THE OVERLAP IS TO BE RETROFITTED ONTO AN EXISTING 2.MANUFACTURER REQUIREMENTS.GUARD FENCE TO BE INSTALLED ON A 40m RADIUS OR TO 1.

NO TRANSITION (OFFSET TO TRAFFIC LANE IS REDUCED)2.OFFSET IN FRONT OF THE EXSITING BARRIER.INSTALL THE APPROACH BARRIER TO THE DESIRED 1.


GENERAL NOTES

A

B

C

D

E


DESIGNED

HOR

VER

SCALE OF METRES

13-Jun-17

3:5

0:2

0 P

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166030-FLP-18.d

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APPROVED

PTY LTD

166030-FLP-18