Published: 3 September 2015 | Category: Technical advice note | Audiences: Road controlling authorities, Road traffic engineers & consultants, Roading contractors
Road Safety Hardware Update – Temporary Concrete Barrier TCB-1
As advised on 5 March this year, the Transport Agency has developed a standard design for public domain temporary concrete road safety barriers using a ‘pin and loop’ connection. This has been done to raise the standard of performance of public domain temporary concrete road safety barrier systems and mitigate some of the issues associated with the manufacture and use of temporary concrete road safety barriers.
From 1 October 2015, all new public domain temporary concrete road safety barrier units used on state highways must conform to the Transport Agency TCB-1 design, unless a specific departure has been granted by the National Traffic & Safety Manager.
This change applies to all new Transport Agency projects awarded after the date of enactment (1 October 2015) and to any current Transport Agency projects where the proposed change can be accommodated subject to appropriate value assessment.
The Transport Agency temporary concrete road safety barrier design TCB-1 is a metricated variant of the Oregon State Department of Transport (ODoT) F-shape ’Precast Concrete Barrier Pin and Loop Assembly’ (RD500). This is an accepted F shape public domain temporary concrete road safety barrier system that has been tested in accordance with the United States Federal Highways Administration (FHWA) National Cooperative Highways Research Programme Project 350 (NCHRP350) protocol.
The chosen system is considered an appropriate solution for temporary traffic management sites on the state highway network.
This change applies to all new Transport Agency projects commencing after the date of enactment (1 October 2015), and to any current Transport Agency projects where the proposed change can be accommodated subject to appropriate value assessment.
Currently accepted proprietary temporary concrete barrier systems are not affected.
All undamaged public domain temporary concrete road safety barrier units not compliant with the new Transport Agency TCB-1 design must be permanently removed from service at end of contract (Transport Agency capital works projects) or within 12 months (30 September 2016) for all Transport Agency maintenance contracts.
Damaged temporary concrete barrier units, both public domain and proprietary, are not considered fit for purpose and must be removed from site immediately, irrespective of system type (refer also NZ Transport Agency letter ‘Temporary Concrete Road Safety Barrier Connections - Notice of Inappropriate Practices’ February 2014).
At all times, all road safety hardware used for temporary traffic management on state highway sites must be correctly manufactured, in good condition and installed in accordance with the
supplier’s instructions by appropriately trained persons.
To facilitate inventory control, from 1 October 2015, all units manufactured to the Transport Agency TCB-1 design and all proprietary design temporary concrete road safety barrier units must be permanently identified either by (1) provision of an embossed date of manufacture and manufacturer’s name/initials on both traffic faces, or (2) use of an RFID tag incorporated in the concrete mix at manufacture.
Corporate logos or other branding may not be embossed on any traffic face.
Notwithstanding the introduction of the Transport Agency public domain design, any temporary concrete road safety barrier units for which the presence of internal reinforcement meeting the requirements of NZTA Specification M23 cannot be readily proven during an on-site inspection will be deemed not fit for purpose and must be removed from site immediately.
The Transport Agency has an objective to make resource efficiency an integral part of all state highway activities. To help meet this objective, the Agency requests that all non-compliant temporary concrete road safety barrier units removed from site are managed in the following order of priority:
After 30 September 2016, the use of any non-compliant temporary concrete road safety barrier units identified during CoPTTM audits or other site inspections will be considered non-compliant practice, rated as ‘dangerous’ in accordance with CoPTTM section A8, and a notice of non-conformance will be issued.
In 1999, the road safety barrier standard AS/NZS3845 was introduced and implemented by Transit NZ through its M23 specification. These documents introduced the F-shape concrete barrier profile as a replacement for the older New Jersey Barrier (NJB) profile. The F-shape profile was developed in the late 1980s to replace the NJB profile which was developed in the early 1950s. The F-shape profile gives better safety performance for light vehicles.
Despite the widespread adoption of the F-shape profile in permanent installations, NJB profile continued to be used in temporary situations. In addition, many temporary barrier installations are poorly configured and use barrier units in poor condition, both factors which could lead to adverse outcomes for both workers and road users should an impact occur.
With the Transport Agency’s adoption of Safe System thinking and focus on Zero Harm, the decision was made to retire all non-compliant barrier units and replace them with a crash tested system.
Author: NZ Transport Agency
Published: September 2015
Version: Rev 2
Reference: TCB-1
Found at: http://www.nzta.govt.nz/roads-and-rail/road-engineering/road-safety-hardware/standarddrawings/
Contact Julian Chisnall of the Highways and Network Operations’ Safety team at julian.chisnall@nzta.govt.nz.
Kevin Reid
