WestConnex Tunnels & Rozelle Interchange, Australia

Project type:

  • Road tunnels 


  • Permanent sprayed concrete linings


  • Owner: Sydney Motorway Corporation 
  • Contractors: Acciona Samsung Bouygues JV & John Holland CPB JV
  • Concrete Supplier: Hanson

WestConnex is a 33-kilometer (21 mi) predominantly underground motorway tunnel network in Sydney, New South Wales, Australia. Its walls are lined with two permanent sprayed layers: one is a fiber reinforced primary support lining, the other is a fiber reinforced concrete smoothing layer. Both are reinforced with Dramix® 4D 65/35 steel fiber for optimal load-bearing capacity.

The challenge

Like many road tunnels in Australia, these tunnels are designed as drained with a permanent sprayed concrete lining. In this case, because of the low cover and its permeable nature and the proximity of the Wolli Creek. 


The solution

A spray applied waterproofing membrane was added between the layers of concrete. Both the primary support lining and the final lining are reinforced with Dramix® 4D 65/35 steel fibers, providing flexural tensile strength of 40 MPa. The primary lining is about 300- 350mm thick and contains 35-40 kg/m3 of steel fibers. The secondary lining is 200-300 mm thick with 40 kg/m3 of steel fibers & 1 kg polypropylene fibers for fire resistance.