Weakleys Drive Interchange

Reinforced Earth® Walls

Beresfield, NSW, Australia
Roads and Traffic Authority
Roads and Traffic Authority
Fulton Hogan
March 2007

The Weakleys Drive Interchange project involved the elevation of the New England Highway over the intersection with Weakleys Drive and the extension of Weakleys Drive to a new roundabout at Glenwood Drive. Located in the Hunter Valley region of NSW, the aim of the project was to reduce traffic congestion and increase safety for motorists.

The Roads and Traffic Authority (RTA) approached The Reinforced Earth Company (RECO) directly to undertake a design of the Reinforced Earth® retaining walls for the New England Highway flyover. The project was then competitively tendered for supply.

During the design process, the RTA specified a horizontal rib finish be used on the facing of the retaining walls.  This finish, as well as issues identified during the design process, presented RECO with many challenges.

RECO designed, and later supplied six Reinforced Earth® retaining walls for the Weakleys Drive Interchange. The TerraPlus® system was used for these structures.  TerraPlus® is Reinforced Earth’s square or rectangular shaped, modular, precast concrete facing panel system. RECO developed it in response to client demand for non-proprietary shaped panels and the widespread popularity growth of project specific architectural finishes. Its broad market acceptance is a result of its ability to accept a wide range of architectural finishes, rapid, easy construction and good performance on soft foundations.

During the up-front design process, not only did RECO guide the client with respect to coping with foundation issues, internal design and aesthetic issues, but also identified various issues / problems before the project went out to tender thereby reducing the RTA’s exposure to unforeseen variations, says John Ritchie, RECO’s Sales and Marketing Manager.

The design process involved multiple iterations, for which the accompanying drawings were all done in 3-D: a lengthy process, which RECO repeated diligently until the right design was achieved.

One of the challenges on this project was mediating between the RTA and the precaster, Beresfield Concrete Products (P/L) (BCP) to ensure the panel finish met with the client’s needs. The panel detailing incorporated clean-cut indentations and ridges, as well as an off-form finish, with a pebbled appearance. The RECO Project Manager went to site regularly to maintain contact with the client and installer. His main activities whilst on site were quality assurance, client relations and logistical planning to ensure there were no delays between the supply of products and the construction.

  • RECO did an up-front design leading to a smooth transition from design in to construction.
  • During the design RECO guided the client with respect to coping with foundation issues, internal design and aesthetic issues.
  • A unique horizontal rib finish was developed for this project.
  • Typically, a more random architectural finish would provide more capacity to accommodate wall movement from the poor foundation conditions without obvious distortion of the desired architectural effect. In this instance however, the RTA was very keen to adopt the horizontal ribs to the walls. It is arguable as to whether this was a good decision and the long-term aesthetics of the walls will be of interest.

Adrian McRae, Project Manager, Fulton Hogan gave the following feedback “it has been a good experience with RECO on this project, I wish you luck in the future, and hope to work together again on future projects.”

Project Specifications

Retaining Walls
818m (total)
Design Load
Design Load 25kPa
Design Life
100 years
Horizontal Rib

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