Advancing Road Safety and Construction

Technical note: NZTA has accepted Nu-Guard 31™ versions of Trailing Terminal End and Curved Terminal Installation at an intersection with a minor road

The New Zealand Transport Agency (NZTA) has accepted for use on the State Highway network two details specifically for the Nu-Guard 31™ steel guardrail system.

Detail One

The Nu-Guard 31™ Trailing Terminal End has the same installation height of 635mm to the centre of the rail as the Nu-Guard 31™ system. This  means that a transition in height from 635mm to 550mm to centre of the guardrail over two lengths to a trailing terminal is no longer required.

To view Drawing FX611 for the Nu-Guard 31™ Trailing Terminal End, click here

Detail Two

The Nu-Guard 31™ Curved Terminal Installation details the correct layout and configuration of a curved terminal installation at the intersection with a minor road when using the Nu-Guard 31™ system.  This drawing covers all new installations and maintenance situations.

The main points of this drawing are as follows:

• To be used with the Nu-Guard 31™ guardrail system only
• Must use a Nu-Guard 31™ Trailing Terminal End
• The installation height should be 635mm to the centre of the guardrail
• A curved trailing terminal should only be installed on a low speed, low volume road. For a high speed, high volume road a X-350 31 Terminal End must be used
• An intermediate anchor must be used at the last rail before the curve commences
• Minimum clear zone of 22m x 6m to be provided behind the guardrail
• The rail rests on a shelf angle at the apex of the curve with no bolt through the rail
• There can be up to three apex posts depending on the most likely vehicle impact direction

To view drawing FX566-1 for the Nu-Guard 31™ Curved Terminal Installation, click here

To view the NZTA acceptance letter, click here

Nu-Guard 31™ is the only 12g W-beam guardrail system that has been tested and accepted to both NCHRP 350 TL-3 and TL-4. It has also been tested and meets the requirements of MASH TL-3 for a 2270kg vehicle.

The system has a maximum deflection of 1.2m for median and roadside applications at NCHRP350 TL-4 and a 1.05m deflection at MASH TL-3 criteria.

For more information about Nu-Guard 31™ Steel Guardrail System click here or
Email: cspcustomerservice@csppacific.co.nz or
Phone: 0800 655 200.