Kwinana Freeway Interchanges and Extension – Berrigan Drive-to-Safety Bay Road


This multi-million dollar extension of the Kwinana Freeway helped to transform the State’s freeway network by delivering several benefits including, significantly reduced traffic congestion and improved operational efficiency of the network.

BG&E set new standards in design and construct solutions with the bridge, tunnels, underpasses and associated works for this project.

This included designing 12 bridges with varying requirements for width and span. A combination of single and two-span structures, with the freeway bridges having spans from 26 metres up to 48 metres. Specific architectural and engineering requirements by Main Roads WA were addressed in our solution of wide pre-tensioned precast concrete trough beams acting compositely with insitu concrete decks and supported on bifurcated columns. Semi spill-through reinforced earth abutments employing full height concrete panels, curve shaped in plan, maintain a uniformity in construction theme with earlier structures provided on the freeway. Insitu concrete columns formed in precast voided sections associated with the reinforced earth facing panels transfer loads from the superstructure to the foundations below.

Our team also designed three pinned precast concrete arched structures at Glen Iris, Anketell and Safety Bay Road (rail tunnels planned for future use). For the first two structures, insitu concrete retaining walls are incorporated along the entrance and exit ramps. At Safety Bay Road, mechanically stabilised earth walls have been employed at both ends of the tunnel structure.

BG&E also designed seven DUP underpasses as insitu reinforced concrete structures incorporating a central light well.

Fast forward to 2021 and the Glen Iris Tunnel, which is key part of the freeway extension, is now earmarked to be used as part of Perth’s first East-West rail link.

The Thornlie-Cockburn Link will be the city’s inaugural East-West cross line connection, making travelling around the city by train more flexible and providing improved public transport for the communities in the southern suburbs. BG&E is contributing to this project.


Fremantle and Rockingham, Western Australia



Main Roads Western Australia and Public Transport Authority

Curiosity, Bravery & Trust

World-Class Engineering