ACEgrid / Terralink Retaining Solution

Palm Beach to Tugun, M1 Pacific Motorway

Project Snapshot

The Pacific Motorway (M1) between Palm Beach and Tugun is the third and final section of the M1 Pacific Motorway VL2T upgrade. It is currently under construction and includes the widening of a 5km section of the motorway between Nineteenth Avenue Overpass and the Tugun interchange.

The works package includes upgrading the motorway from 4 to 6 lanes along with rehabilitation and reconstruction of pavements, lengthening of entry ramps and exit ramps, demolition and reconstruction of 7 new bridges and widening of 3 bridges.

Reconfiguration of intersections and service roads will also be completed, along with ancillary works including construction of retaining walls, signals, noise fences, road lighting and smart motorway infrastructure.

The Challenges

This stretch of the M1 Motorway required retaining structures to support the road surface, and specifically, soil reinforced retaining structures that could handle very steep face angles in certain areas.

The chosen solution incorporated the Terralink® steel mesh facing system from Global Synthetics, with ACEGrid® polyester geogrid used as the soil reinforcement element. Supply commenced in early 2021, with the specialist wall builder engaged by the principal contractor responsible for the construction of the ACEGrid® reinforced Terralink® system.

Our Solution

Terralink® was chosen for its flexibility and ability to vary the face angle to suit between 45 and 70 degrees (and in some cases even steeper). The Terralink® panel facing provides stability and ease of construction whilst also comfortably accommodating some expected short-term settlement.

Global Synthetics worked closely with TMR, the contractor, the designer, and the construction team to deliver a successful completion of the structures over the course of the project.

After a 2 year settlement period, the Terralink® facing units will have an additional layer of welded mesh reinforcement attached to the protruding steel connection bars that were installed during the construction phase.

These connection bars serve the dual purpose of providing an effective support system for fall protection during construction, as well as creating a positive connection for the attachment of the final facing. The bars will connect to the steel mesh reinforced, sprayed concrete facing, providing further durability.

During this project, Global Synthetics also assisted TMR and the contractor with site supervision and training to ensure a quality outcome.