Overview
In early 2014, AECOM (formerly URS Australia Pty Ltd) were awarded through Victoria International Container Terminal Limited (VICT), the engineering design works (including geotechnical investigations and construction phase services) for a new container terminal with an extra capacity of 1 million+ twenty foot equivalent units (TEUs). The Webb Dock East development is part of a $1.6 billion port upgrade in the Port of Melbourne. It is Australia’s first fully automated terminal.

The project included developing 35.4ha within the terminal area and the operation of 5 post-Panamax ship-to-shore cranes (STS), 20 Automatic Stacking Cranes (ASC) and 11 Automatic Container Carriers (ACC), making VICT one of the most advanced terminals in the world.

Challenges
The operational tolerance of ASCs imposes tight restrictions on the vertical and lateral displacements of rail foundations. This created significant design challenges due to the highly compressible marine clays which underlay the entire project area. Extensive ground improvement were implemented in order to meet the design requirements.

Two of the most important design considerations for the automated container handling system were the rail foundations for the ASC, and the plinth foundations for stacking containers. In order to manage ground settlement issues, an adjustable rail and ballast system was adopted which can manage rail and track settlement of up to approximately 350mm. The container plinth foundations are required to support the loads of corner casts of containers stacked five high whilst also ensuring the settlements induced by the loads are complying with the ASC operational tolerances. It was estimated that without the ground improvements, the current development could potentially be subjected to settlement of up to 500mm over the 27 year design life. Consequently, ground improvement was conducted with the aim of limiting post construction settlement to be no greater than 150mm. A range of ground treatments were adopted which are outlined in our approach below.

Approach
Our collaborative approach to achieving success was to align our experienced team to work in close partnership with the VICT team, providing a high level of service, consistently meeting and often exceeding expectations, assisting both VICT and contractor to achieve the project goal. In addition, AECOM leveraged industry-leading knowledge from our international ports team.

Depending on the site reclamation history, compressible soil layer thickness and the operational requirements imposed by the development adopted techniques included a combination of the following:

  • Controlled modulus columns (CMCs) for areas underlain by more than 5m compressible clay and with estimated long term settlement ≥ 350mm
  • Preloading with 3 to 5m high surcharge fill for areas underlain by up to 5m compressible clay with estimated long term settlement between 150 and 350mm
  • Impact compaction for areas with estimated long term settlement <150mm (primarily to improve the upper fill materials).

This project required significant input from our Sydney, Brisbane and Adelaide offices. Technical supports for ground improvements and pavements were also provided by our offices in United States, Hong Kong and UK.

Value

  • Delivering ahead of schedule: Geotechnical investigations were completed three months ahead of schedule. The overall project was delivered eight months ahead of schedule with 1.8m hours lost time injury (LTI) free.
  • Reducing risk: Innovative ground improvement methods were employed to reduce risks during the construction stage. These mitigating measures can be attributed to the innovative ground improvement methodology developed by AECOM.
  • Cost savings: Project savings estimated at between $5m-$8m through design and project optimisation, working closely with VICT to ensure expectation and contract deliverables were achieved.

In early 2017, VICT achieved two of the highest possible rating categories of “Leading” from the Infrastructure Sustainability Council of Australia (ISCA) for both VICT’s sustainable design and build and was awarded the Smart Infrastructure Project of the Year Award by Infrastructure Partnerships Australia.