Enhancing road safety and efficiency as part of the Tonkin Gap project
At a glance
As part of the Tonkin Gap Alliance, we partnered with Main Roads WA and Public Transport Authority to design and deliver a solution to alleviate the bottleneck along Tonkin Highway between Dunreath Drive and Collier Road. The project has significant benefits for commuters through reduced travel time and enhanced road safety along the corridor to and from the airport. Additionally, the Alliance was tasked with delivering significant rail enabling works for the future METRONET Morley-Ellenbrook Line.
The Tonkin Gap project and associated works was delivered by BMD, Georgiou, WA Limestone, GHD and BG&E, together with Main Roads WA and the Public Transport Authority.
The challenge
This $400M project addressed a major bottleneck on Tonkin Highway between the Gateway WA and Northlink WA projects. It also involved preparing the existing corridor to construct the METRONET Morley-Ellenbrook Line. Upgrades included additional lanes, upgraded interchanges, new bridges, shared path connectivity and rail-enabling works.
Major components of the project included:
- Removal and replacement of Broun Avenue Bridge.
- Duplication of the Redcliffe Bridge (now Mooro-Beeloo), comprising a 330m launched structure over the Swan River.
- Upgrades to improve existing interchanges at Great Eastern Highway and Guildford Road.
- A total of 8 bridges and 3 footbridges over the Swan River, Dunstone Road, Railway Parade and Guildford Road.
- 3.1 kilometres of new and upgraded Principal Shared Path (PSP) along Tonkin Highway.
- Rail-enabling works for METRONET Morley-Ellenbrook Line.
- BMX and mountain bike recreation area under the Mooro-Beeloo Bridge.
- Two dive structures to facilitate the railway entering and exiting the Tonkin Highway median.
The project site posed several challenges including the constrained footprint, substandard and variable ground conditions, and high groundwater. We also needed to maintain traffic flows through the busy corridor during construction.
Our response
Our team worked to overcome the challenges by implementing an integrated design solution that considered constructability, environmental and other stakeholder imperatives. We mobilised a highly skilled technical team, responding to the need to stimulate the local economy quickly during the COVID-19 pandemic.
Construction of Mooro-Beeloo Bridge
Water drainage
We adopted innovative design solutions to address these challenges, including overlapping or abutting new and existing structures, optimising construction methodologies with integral and launched bridges, underpinning existing structures and strengthening existing structures.
Sustainability
Given the high impact the infrastructure construction industry has across environmental, social, local economic and governance factors, sustainability was a key focus of the project. Through our ‘Australia first’ design and construction innovations on the project, we predicted reductions across all key areas, including a 6% reduction in water usage, 4% lower energy use and a 12% reduction in embodied carbon from material use through design and construction innovations.
Our team has also explored opportunities to maximise the use of recycled materials. 30,000 tonnes of crushed recycled concrete was used, replacing traditional crushed limestone road base.
In 2023, the Tonkin Gap Alliance achieved a Gold Infrastructure Sustainability (IS) Design rating from the Infrastructure Sustainability Council on the Tonkin Gap Project and associated works in Western Australia. This award recognised the success of the entire team in adopting and driving sustainable approaches to drive governance, economic, environmental and social outcomes through detailed design and construction planning.
The impact
Construction began in November 2020, with works completed in 2024, on time despite several challenges, including the peak of COVID-19.
The local community has gained significant advantages with relieved congestion on Tonkin Highway and enhanced safety and connectivity across key Western Australian roadways.
The upgrades have saved road users up to six minutes of travel time during morning peak and up to 11 minutes of travel time during afternoon peak.
“Our team is thrilled with the project's success. Along with our valued Alliance members, we're proud to have contributed our technical knowledge to a critical road infrastructure project in WA. Being part of this initiative underscores our commitment to setting new benchmarks for sustainable infrastructure development and creating lasting community benefit for generations to come.” Alexandra Piper, Project Director, GHD.