A new innovation precinct in Fishermans Bend is set to position Victoria as a global leader in engineering, manufacturing and design. However, before the redevelopment work could start, there was the complex task of augmenting the existing power network. Daly’s Constructions had to innovate to combat weak ground conditions, traffic management constraints and to navigate 150 existing underground services.
The General Motors Holden (GMH) site situated in Fishermans Bend in Port Melbourne was one of the cornerstone locations for car and propulsion systems manufacturing in Australia for more than 60 years.
Following the factory’s closure in 2016, the Victorian Government pledged $179.4 million to redevelop the site into a technology precinct that will place Victoria at the forefront of global innovation. To facilitate the precinct’s development, Daly’s Constructions was engaged by Powercor Network Services on behalf of CitiPower to augment the existing 66kV and 11kV networks.
The contract, awarded in July 2022, saw Daly’s Constructions responsible for the installation of the 2.2km long dual circuit 66kV conduit bank; the design, manufacture and installation of two 18t precast joint bays; 66kV cable hauling; the installation of the 2.5km of optic fibre cable and 2.6km of full depth road remediation. The company was also in charge of project management and construction planning, as well as obtaining DoT/VicRoads approvals and traffic management.
The mission
The design consisted of a dual 66kV circuit, one to be used for the GMH site redevelopment and the other to support future CitiPower works. Due to the complexity of the project, detailed planning had to be conducted prior to mobilisation. These preparations included:
- Safe excavation procedures within sandy soils
- Traffic impact analysis and traffic management planning along Salmon Street, Cook Street and Todd Road
- Procedures to navigate the numerous underground utilities and service crossings, including existing oil-filled 66kV cables
- Liaising with and obtaining works consents/approvals from:
- Department of Transport (DoT)/VicRoads
- City of Melbourne
- National Heavy Vehicle Regulator
- Development Victoria
- Local businesses directly impacted by works
Innovative solutions
One of the key challenges experienced during the project was excavating in sandy soils common to the Port Melbourne area, and navigating more than 150 underground services and utilities.
Due to the weak ground conditions and large zone of influence adjacent to the trench the risk of the trench collapsing was very high, which required the use of special, aluminium shoring boxes. In addition, Daly’s Constructions’ experienced operators needed to mitigate the trench sidewall from subsiding, and prevent sand from falling into the trench prior to the placement of fluidised thermal backfill (FTB).
The team also had to manage the shallow water table and dewatering the trench, which saw the removal and disposal of more than 150,000L of groundwater in a single shift. Another challenge was the traffic management required to facilitate the works.
To mitigate the traffic impact, Daly’s Constructions divided the work into six separate stages that involved full road closures of Salmon Street, Cook Street and Todd Road, which are the main access roads into and out of the Port of Melbourne. With the land-locked nature of the roads in the area, the staged diversions involved sending oversized vehicles around the site.
Approximately 150 existing services were crossed along the 2.2km route with zero damage. These assets included large stormwater drains and water mains, to live 66kV oilfilled power cables, gas services and optic fibre transmission cables, several of which were not present on the tender design and Dial Before You Dig (DBYD) information. Daly’s Constructions remained in constant communication with the Powercor Network Service project team to manage alignment changes and to ensure that the circuit rating was maintained.
One of the most challenging sections was at the intersection of Salmon Street and Cook Road, in particular the section beneath the Salmon Street bridge. In this 15m section Daly’s Constructions had to navigate existing 66kV oil-filled cables, large stormwater drains, gas mains, and optic fibre cables. This was completed safely over three shifts with no outages required on the existing 66kV cables, which was a great outcome for the client.
Another key innovation was the use of precast concrete joint bays instead of in-situ construction. The joint bays weighed 18t each and were designed by Daly’s Constructions to meet Powercor Network Services jointing requirements. The use of precast joint bays saved time and cost, and assisted in relieving the pressure Daly’s Constructions faced to reopen the roads and restore traffic.
Other achievements included the removal of more than 12,000t of contaminated spoil to EPA requirements, installation of the 2.2km long dual circuit 66kV conduit bank in less than six months, managing procurement of more than 5,000m³ of fluidised thermal backfill and the completion of nine 750m 66kV cable hauls in six days.
Daly’s Projects Manager, Givantha Silva credits the success of the project to close collaboration between Daly’s Constructions and the Powercor Network Services project team.
“This collaborative approach allowed for effective planning and permitted our skilled workforce to deliver the project on time and to a high standard,” Mr Silva said. The completion of the Fishermans Bend 66kV and 11kV project will facilitate the future works at the GMH innovation precinct that will place Victoria at the forefront of global innovation.
This sponsored editorial is brought to you by Daly’s Constructions. For more information, please contact Daly’s Constructions on (03) 9360 9485 or visit dalysconstructions.com.au.
