Coulson Steet, Wacol, Brisbane – MagnumStone™

GPT were looking to develop a large commercial warehousing development in Coulson Street, Wacol. Due to a sloping site, three large retaining walls were required to provide a flat site to allow the warehouse to be constructed.

Cirtex was approached to provide a solution using the MagnumStone system for the two large MSE walls. When analysing the site, Cirtex also proposed the MagnumStone Gravity Wall system as a possible option to replace the soldier pile wall at the back of the site. The MagnumStone Gravity System was selected for this area as it provided a faster program along with some significant cost savings when compared to the existing design.

DESIGN

Retaining Wall 1 was a MagnumStone MSE wall with StrataGrid reinforcement retaining one side of the site beside a creek, designed to a maximum retained height of 4.9m with 20kPa live load from the traffic accessing the carpark.

Retaining Wall 2 was a MagnumStone Gravity wall retaining the back boundary. Retained to a height of 3.4m with a significant back slope to the adjacent property, this wall also extended approximately 30m down each side of the site to where the cut finished. The MagnumStone Gravity design with extenders minimised the footprint of the wall, providing greater land usage.

Retaining Wall 3, the largest wall on the site, was designed as a MSE structure using StrataGrid reinforcement. Retained to a height of 7.9m, it ran across the front of the warehouse, supporting both the building loads and live loads of the equipment operating inside.

INSTALLATION

Using the MagnumStone system for all three retaining walls provided significant time and programme advantages. It removed the need for the lengthy and costly process of installing soldier piles along the back boundary. It allowed for the fill works under the building to work in transition with the construction of the MSE retaining walls at the front and side of the site, and it allowed Brisbane Civil to construct the walls using their own crew to improve the schedule of construction.

Cirtex provided extensive onsite support and training to the project to ensure the walls were constructed efficiently, effectively and to the required specification. Because MagnumStone can be built using extenders for a gravity wall or with StrataGrid for a MSE structure, the wall face aesthetics remain the same, providing a versatile solution for any retaining wall requirement.

The MagnumStone system provided the following benefits to the project:

• Quick and easy to install.
• Able to be built using gravity or MSE methods without any change to aesthetics.
• Allowed a faster works program on site.
• Was able to support the large building dead loads + live loads from equipment inside the building.