M4 and M5 Link Project

2 January 2023

The $3.2Bn extensions to the M4 and M8 Project is a critical component of WestConnex and links the M4 at Haberfield to the M8 at St Peters.

Investructure provided the Project Director, successfully delivering ahead of time on budget the WestConnex extensions to the M4 and M8 for TfNSW. Other services were provided, including, integration and interface management, assurance, and compliance.

The 7.5 kilometre underground mega tunnels connect the two motorways, providing a seamless link between Haberfield and St Peters and cutting travel times by up to 40 minutes between Western Sydney and Sydney Kingsford Smith Airport. An integrated digital 3D model was developed for the tunnel and internal structures to establish the optimum spatial requirements and space proofing for the large span and tunnel length. Space proofing ensured that all required functions are accommodated within the planned tunnel volume. The tunnel excavations span almost 34 metres in order to accommodate the 5 lane traffic sections at the eight underground caverns where traffic will merge and diverge at the interchange ramps along the route. At 34 metres wide, the largest tunnel cavern is large enough to hold a Boeing 737-300 nose to tail across the vast space.

The project will also include future links to the Western Harbour Tunnel, Sydney Gateway and the M6, to better connect communities across the city and improve freight routes.