29 August 2016

Technical Talk - Wire Rope Safety Barrier Transitions

In November 2014 the New Zealand Transport Agency published Technical Memorandum TM-2013 on wire rope safety barrier (WRSB) transitions.

TM-2013 advised on the recommended practice for the design and installation when transitioning from a wire rope safety barrier (flexible) to a W-Beam (semi-rigid) or Concrete (rigid) barrier. The memorandum covers the layout for median and side protection situations, for example when approaching a bridge structure or sign gantry.

Click here to view the drawing for X-350/Armorwire transition.

Key points to note:

  • In the transition, the semi-rigid system should always be closest to the carriageway so an impacting vehicle will impact that system first.
  • Offsets shown are measured from the face of semi-rigid barrier (W-Beam or Thrie-Beam) to centreline of WRSB.
  • The end point of the W-Beam leading terminal must align with or overlap the point of redirection of the WRSB system.
  • Any design variation to the details in TM-2013 must be signed off by the Transport Agency National Office before installation.