c. 2020 pitt & sherry

Deer Park Bypass Western Highway Deviation

Melbourne, Australia

VicRoads awarded the design and construct contract for the Deer Park Bypass in Western Melbourne to Akron Roads. The contract was let in advance of broader construction of the 9.3 km bypass from the Western Ring Road at Sunshine West to the Western Highway at Caroline Springs. The primary purpose of this advanced contract was to alleviate the impact of construction on the community. The early construction of this structure allowed construction staging of the overall project to have minimal impact on existing road users and the community.

The project involved the design of approximately 2 km of the realignment of both carriageways of the Western Highway to allow for the later connection to the Deer Park Bypass Freeway. The completed bypass allows traffic to and from the Ring Road to travel at freeway speeds, avoiding twenty intersections and many traffic signals compared with the old Western Highway route.

A 9 km cycling and walking path known as the Wellness Trail runs adjacent to the bypass. The trail includes rest stops featuring mosaic artworks created by adult mental health patients at Sunshine Hospital.

pitt&sherry was engaged by Akron Roads to undertake the detailed road and bridge design for the $10 million interchange between the Western Highway and Deer Park Freeway. The design included innovative road geometry to fit a difficult layout and a unique bridge design.

The bridge was an 87 m long, two-span structure constructed from three sets of 1,500 mm deep prestressed precast Super-T beams. The central beams were installed over the piers and made continuous with the other beams through a cast in-situ stitch. The innovative design allowed a clear span much greater than would be usual for this depth of beam. The solution offered significant cost savings on the bridge and approach earthworks.

The construction of these advanced works were able to proceed in a relatively Greenfield environment. This allowed the installation of substantial temporary falsework under the bridge without impacting on construction. Once completed, the new road and bridge were opened up to traffic to allow construction of the main bypass.

The scope of detailed design undertaken by pitt&sherry included:

  • two lanes in each direction, with provision for an additional lane each way in the future when needed;
  • freeway interchanges with direct access at the Western Highway, Christies Road, Robinsons Road and at the Western Ring Road;
  • overpasses of the Melbourne–Ballarat railway line and Riding Boundary Road, Ravenhall;
  • a bridge to take Mt Derrimut Road over the bypass;
  • noise walls at some locations to help reduce traffic noise impacts on nearby residential areas;
  • Wellness Trail shared path for pedestrians and cyclists adjacent to the bypass route.

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