Gallipoli Underpass
A landmark upgrade to one of Adelaide's busiest intersections


The Gallipoli Underpass is a landmark, award-winning project upgrading South Rd and Anzac Highway at one of Adelaide’s most high profile and busy intersections.


The project required the grade separation of both roads at the main South Road/Anzac Highway intersection via an underpass that includes a 31 m span bridge and construction of extra lane width. The bridge consists of 3 lanes and a turning lane in each direction and was built in two halves with T-beam and CFA piles. The works included:

  • 3,000 m³ structural concrete
  • 1.5 km post-tensioned soil nailing
  • 800 t precast beams and installation
  • 50,000 m³ earthworks
  • 1,000 m³ shotcrete
  • Demolition of numerous structures
  • Relocation of major services
  • Traffic management
  • Noisewall construction


Collaboration drives innovation

The collaborative ECI process led to significant improvements on the reference design. The selection of a double diamond interchange, rather than the originally proposed single point urban interchange, meant that the extent of bridge deck could be reduced, U-turns could be included, and pedestrian crossings could be staged, significantly reducing congestion.

The project’s Value for Money team identified early on that several structural components of the project were high-cost items. Innovative solutions were developed to address this, including:

  • The inclusion of integral bridge abutments for lower maintenance, simplicity, robustness and lower cost
  • Designing the bridge to accommodate live loading before the deck was complete, to minimise traffic delays and provide flexibility in staging.

The Value for Money and Innovations teams achieved a saving of 25 per cent of the Principal’s budget. Further refinement of the design and a thorough constructability review led to a further 11 per cent saving in the construction price.

Reducing impact on road users through design and construction coordination

The ECI process enabled the team to develop a low-impact construction solution for the intersection, with major excavation work occurring west of the alignment of the existing South Road. This allowed traffic to continue to operate throughout construction and avoided significant service relocations. Strong coordination between the design and construction teams allowed for accurate and effective traffic simulation, which further reduced traffic impacts. Works for this project were undertaken with no complete shutdowns of South Road and only five weekend restrictions on Anzac Highway, with buses still in operation.

Integrated stakeholder engagement teams contribute to project success

The inclusion of consultation specialists in the team enabled designers to integrate community concerns and ideas into the engineering design. Community stakeholders were engaged through innovative strategies, including ‘flyover’ visualisations and traffic simulations. The project has received outstanding levels of stakeholder satisfaction and is an iconic feature of Adelaide's western suburbs.


2007 Engineers Australia

2007 Engineers Australia (SA) Malcolm Kinnaird Award - Overall Best Project

2011 CCAA Public Domain National Awards


2011 CCAA Public Domain SA Awards

State Winner

2009 CCF (SA) Earth Awards

Category 4

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