Flexrail™ W-beam is the most common roadside crash barrier in use in New Zealand.

The current W-beam barrier shape became the standard in the USA in the 1950's and was first introduced into New Zealand in the early 1960's, manufacture of Highway guardrail in New Zealand began in the early 1970's. Later Bridge guardrail was developed (with limited static testing of rail joints) in New Zealand by the Ministry of Works and Development (MWD), in conjunction with CSP Pacific.

CSP Pacific currently supplies two standard types of Flexrail™ W-beam guardrail.

• Highway Flexrail: 3.81m effective length
• Bridge Flexrail: 4.0m effective length

Manufacture

Flexrail™ is roll formed from coil steel and sheared to length. It is then punched, slotted and hot dip galvanised in accordance with AS/NZS 3845: 1999.

Flexrail™ is available ex-stock in standard effective lengths of 3.81 metres and 1.905 metres for Highway rail and 4.00 metres and 2.00 metres for Bridge rail.

Curved Flexrail™

The standard straight section will align to give a smooth transition on curves with a radius greater than 45m. Pre-curved Flexrail™ is required for tighter radii and may be curved to traffic face concave or convex - see table below. NB: Only Highway Flexrail is available pre-curved.

Standards and Approvals

Flexrail™ W Beam complies with the requirements of:

• AASHTO
• AS/NZS 3845:1999 - Road safety barrier systems
• Transit NZ specifications M/23 and M/17P.