• Capabilities: Engineering
  • Sectors: Transportation

Designing a unique facility for WestConnex

New South Wales, Sydney, Australia - WestConnex is a motorway of more than 30 kilometres, built in three stages linking Sydney’s west with its international gateways and key places of business. It connects Sydney’s M4 and M5 motorways with the city, airport and Port Botany, and includes capacity improvements on existing roads and substantial new sections of motorway. A key part of this is the Parramatta Road Ventilation Facility (PRVF)

45m below

existing ground level

122 piles

around shaft
Aerial view of Designing a unique facility for WestConnex excavation

The PRVF will provide tunnel ventilation for the New M4 Project and the future M4-M5 Link.

Due to the location of the PRVF, innovative solutions were needed to reduce noise output and ensure the impact on the densely-populated community was minimal. To achieve this, a unique shape for the shaft was developed, including three intersecting circular shafts that are each approximately 30m in diameter, to fit on the constrained site at the intersection of Parramatta Road and Wattle Street. Also, most of the PRVF building will be constructed below ground to minimise operational noise.

 Key highlights of the project include:

  • The PRVF will be excavated to approximately 45m below existing ground level.
  • The PRVF building will be constructed from the base of the excavation, with the top of the PRVF building approximately 27m above ground level.
  • To enable the excavation of the PRVF shaft, Arcadis and AECOM designed the excavation retention system at the top of the shaft, which required 122 piles around the perimeter of the shaft.
  • To assist constructability and enable the plan area of the shaft to remain as open as possible during excavation, the pile capping beams are propped by three temporary steel props. These props span over 28m and will be replaced by permanent reinforcement concrete props once the PRVF building structure is built back to ground level.

Arcadis were appointed to provide civil design services for the WestConnex New M4 project in a joint venture with AECOM. As well as the design of the excavation retention system for the PRVF, Arcadis and AECOM delivered geometric and road engineering designs, pavement design, flood assessment and drainage design, traffic engineering services, lighting design, utilities coordination and structural design of the bridges, retaining walls, cut and cover tunnels and buildings.

Designing a unique facility for WestConnex excavation


45m below

existing ground level

122 piles

around shaft


new innovative ventilation facility

Questions about this project

Jarrod Hitchcox

Business Leader - Civil Structures NSW +61 (0) 2 8907 3967 Ask me a question
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