New Zealand Road Side Barrier System Standard Guide

1. NON-PROPRIETARY ROAD SAFETY BARRIER SYSTEMS

1.1 Semi-Rigid Roadside and Median Barriers

Semi-rigid barrier systems approved for use on state highways are shown in Figure 1 and 2: Semi-Rigid Roadside Barriers.These systems are described and detailed in the AASHTO-AGC-ARTBA Joint Committee. Subcommittee on New Highway Materials, Task Force 13 Report:A Guide to Standardized Highway Barrier Hardware – May 1995(Task Force 13 Report).

1.2 Rigid Roadside and Median Barriers

(a)F-Shape Concrete Barrier

Task Force 13 Report Reference:SGM10a-b
Median/Roadside Barrier NOTE:When used as a roadside barrier overall mass and dimensions must not be reduced.For ease of construction roadside barriers may use the optional constant rear slope cross-section.	Roadside Barrier (Optional Constant Rear Slope Cross-Section)
Figure 3: F-Shape Concrete Median and Roadside Barriers

The F-shape concrete barrier system is shown in Figure 3 above.It is also described and detailed in the AASHTO-AGC-ARTBA Joint Committee, Subcommittee on New Highway Materials, Task Force 13 Report:A Guide to Standardized Highway Barrier Hardware – May 1995: System Drawing SGM10a-b.

For New Zealand state highway use the“INTENDED USE”and“COMPONENTS”paragraphs on Sheet 2 of SCM10a-b shall be replaced with the following:

INTENDED USE

The F-shape median barrier is similar to the more common New Jersey shape but the breakpoint is 80mm lower.The barrier has been successfully crash tested according to NCHRP Report 230 and has performed well in the field. Four reinforcement bars are shown but other sizes, numbers and arrangements of reinforcement have been used by state road controlling authorities in the US.The upper longitudinal reinforcement does not provide flexural strength, since it lies on the neutral axis, and it is only intended to prevent large pieces of the barrier breaking off and falling into the traffic lanes in the event of an impact.Additional flexural reinforcement will increase the strength of the barrier in severe impact situations.

A 3m long 250mm deep reinforced anchor footing must be provided at both ends, to properly secure the barrier.Other common methods of supporting the barrier include setting the barrier in a continuous keyed foundation or dowelling the barrier to a foundation.

A top-width of 200mm is usually adequate but some state road controlling authorities in the US have used a top-width of 240mm, to accommodate sign and luminaire supports.

The barrier may be cast-in-place, slip formed or pre cast.Cast-in-place and slip formed barrier will normally be a continuous pour without transverse contraction joints.Cast-in-place segments less than 12m in length must be joined to adjacent sections by at least three 25mm diameter steel dowels, or an equivalent joining method approved by Transit New Zealand.

COMPONENTS

Concrete used in the construction shall comply with the requirements of NZS 3109 and shall be manufactured in accordance with NZS 3104.The minimum concrete cover depth is 40mm.The 28 day compressive strength and concrete binder type shall be in accordance with the durability requirements of NZS 3101 for the relevant exposure classification but in all cases shall be a minimum of 30 MPa.

Reinforcing steel shall be grade 500E or 500N conforming with AS/NZS 4671 and increased from 15 mm to 16 mm.”

1.3 Pre cast Concrete Barriers

(a)The minimum length of a pre cast barrier unit for use in a permanent barrier installation shall be 6.0m.

(b)Concrete shall comply with the requirements of NZS 3109 and shall be manufactured in accordance with NZS 3104.The minimum concrete cover depth is 40mm.The 28 day compressive strength and concrete binder type shall be in accordance with the durability requirements of NZS 3101 for the relevant exposure classification but in all cases shall be a minimum of 30 MPa.

Reinforcing steel shall be grade 500E or 500N conforming with AS/NZS 4671.

(c)Pre cast barrier units must be joined by an approved method capable of transferring operational stresses from one unit to another, i.e. steel dowels, tongue and groove locating system, shear key, etc.

(d)Each end unit in a permanent barrier installation must have a 3m long 250mm deep reinforced anchor footing, to properly secure the barrier.

•the transfer of operational stresses from one unit to another by the joining system, and

•barrier unit handling stresses.

2. PROPRIETARY ROADSIDE AND MEDIAN BARRIERS

2.1 Flexible Barrier Systems

Any installation of post spacings not included in the following tables, requires the approval of the NZTA National Traffic and Safety Manager.

(a)Brifen

The following configuration is approved:

(i)The four rope system as specified on the Brifen website

(www.brifen.com).The system must comply with drawingsLB/01, 04, 07B, 11, 12, 13, 126, 127 and 128, which are available on the Brifen website.

(ii)In addition to the end terminal shown in these drawings, the terminal detail on the FHWA website, reference CC-86 is also permitted.

(iii)NCHRP350 crash tested post spacing and associated deflections are:

(b)Safence Three Cable System

(i)NCHRP350 crash tested spacing and associated deflections are:

(ii)To be used with the Safefence 350 end terminal.

(i)NCHRP350 crash tested spacing and associated deflections are:

(ii)To be used with the Armorwire Terminal End (ATE).

2.2 Semi-Rigid Systems

The following is approved:

(a)NuGuard

The NuGuard system using NuCor posts as shown in the FHWA acceptance letter dated 27 June 2008 (ref HSSD/B-162B, NCHRP350).

3. END TERMINALS, CRASH CUSHIONS AND TRANSITIONS

3.1 Propriety End Terminals

(a)Propriety end terminals approved for use on state highways are listed in Table 1 below.

(b)Other End Terminals

(i)Buried-in-Backslope Anchor

The anchorage of the system must be able to develop the full tensile strength of the W-beam.

(ii)Trailing Terminal – AS/NZS 3845:1999, Figure F10

This terminal can only be used where it cannot be hit head-on by vehicles, ie. on one-way roads and median barrier separated divided carriageway roads.

NOTE:Figure F10

•Steel posts can be replaced with wooden posts at a spacing of 1905mm

•The end post may be attached to a soil plate or slotted into a soil foundation tube.

3.3 Propriety Crash Cushions

Propriety crash cushions approved for use on state highways are listed in Table 2 below.

3.4 Transitions

(a)AS/NZS 3845:1999

NOTE: the 780mm taper on the base of the F-shape barrier should begin at the end of the recess.

(b)W-section to concrete transition using Thriebeam rail.