W-Beam to Thrie-Beam to Type F Barrier Transition – Typical

W-Beam to Thrie-Beam to structure transitions are typically used and specified in guardrail terminations to bridges, concrete abutments, concrete structures and crash cushions.

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Barrier Transition


These barrier transitions are also used to transition into Thrie-Beam installations for reasons such as reducing guardrail deflection and providing greater protection for heavier vehicles typically requiring Test Level 4 crash test performance.

Deployed for guard rails ending at bridges, concrete structures and crash cushions. Because guardrails are more flexible than the objects they attach to. Thus the need for a barrier transition section. Installed where there is a change in the deflection characteristics. For example between a guardrail and crash cushion or concrete structures.


Typically a 6 metre arrangement consisting of a 2 metre W-Beam to Thrie-Beam transition rail followed by a 4 metre Thrie-Beam rail which may be nested or of 3.5mm BMT material, however, state road authorities do vary on the exact requirements and details. Check technical drawings* for further information.


W-Beam to Thrie-Beam Transitions consist of W-Beam, Thrie-Beam, C-Block, C-Posts, Thrie-Beam Terminal Connector (optional) and associated hardware fixings.

Details and requirements such as spacing of posts, rail nesting, terminal connections and installation heights do vary across the different state road authorities. Check your local detail barrier transition drawing/s for further guidance.

Standards and Approvals

W-Beam and Thrie-Beam comply with the requirements of: