The Mitchell Freeway Extension is an important expansion of Perth’s main northern artery by more than four kilometres, from Hodges Drive to Burns Beach Road, through the rapidly growing City of Joondalup. In addition to providing greater connectivity, this project set a new benchmark in community engagement and included an environmental strategy which protected the urban bushland and minimised use of the surrounding natural resources.

BG&E provided the design of the three major road bridges, five pedestrian underpasses, rail tunnel (near Moore Drive under Mitchell Freeway southbound carriageway) and the noise walls.

The Mitchell Freeway alignment was altered adjacent to the Hodges Drive Bridge to enable the bridge to be shortened and resulted in similarities with the other major bridges. This also provided savings in earth works costs, as well as economies of scale.

At the Currambine Station underpasses, the design loads from traffic barriers were carried independently to the proprietary precast units. This approach enabled utilisation of precast box units that are not generally designed for barrier loading.

The northern suburbs rail system was constructed in advance of the freeway extension, which required the realignment of approximately one and a half kilometres of rail track to the south of Currambine Station (located within the freeway median).

Our team also designed the bridges with common format, to ensure consistency and harmony in appearance and public art was incorporated in the precast panels of the road bridge abutments.