By Stephanie Nestor, Assistant Editor, Infrastructure Magazine
The Fitzroy River Bridge formed part of a vital freight route in Western Australia until it was permanently damaged following a cyclone, prompting the construction of a replacement bridge. With a disaster-resilient design, the new bridge promises to support this remote road network by reconnecting communities and industries.
In late December 2022, Tropical Cyclone Ellie crossed the Northern Territory coast and a subsequent tropical low settled over the Fitzroy Crossing, which caused significant damage to roads and bridges. This included several sections of the Great Northern Highway between Broome and Fitzroy Crossing in the Shire of Derby-West Kimberley, and the Fitzroy River Bridge.
The bridge was damaged beyond repair in the largest known flood to date – considered to have exceeded a one-in-100-year flood event – cutting off access to communities and causing disruption to locals, tourists and the freight industry. With the region left disconnected, plans to build a replacement bridge were announced within weeks and a procurement process, which would typically take nine months, was concluded in eight weeks.
A Main Roads Western Australia spokesperson said the Fitzroy River Bridge was the only sealed connection across the river in the vicinity of Fitzroy Crossing, meaning when it was damaged, local communities to the east of Fitzroy Crossing were cut off from key supplies and family members.
“This caused a significant amount of distress in the community and a high level of coordination was required between several agencies to provide essential services whilst connectivity across the river was being restored,” the spokesperson said. “The impact to the freight industry was also severe, necessitating major detours via South Australia and the Northern Territory, resulting in materials and food shortages and higher prices in remote locations.”
Launching in record time
The Fitzroy River Bridge works are funded through the Commonwealth State Disaster Recovery Funding Arrangements, with design and construction to be completed by Main Roads Western Australia and a consortium comprising Georgiou Group Pty Ltd and BMD Constructions Pty Ltd and BG&E.
Following construction beginning in May, the New Fitzroy River Bridge is scheduled to open by the end of 2023, more than six months ahead of schedule. The bridge deck was launched span by span with a 36m segment positioned every four days until completed.
The eight bridge spans were constructed and launched incrementally from a launch pad located on the western side of the river. This construction method was selected to minimise the requirement for works to take place within the river channel, and safeguard the project against the potential of an early wet season.
The spokesperson said, while incredible launching techniques have been commonplace in Australia for decades, the speed at which the span construction, deck pour and launch were completed was unprecedented.
“Each new span was launched on average every four days,” the spokesperson said. “This rate of progress was made possible due to a high level of collaboration with key suppliers and contractors to ensure that components such as bridge beams, bearings and concrete were made available at the time they were required and installed in a quick, but safe manner.”
By investing in disaster-resilient infrastructure, the new Fitzroy River Bridge project will reconnect east and west Kimberley communities and industries, opening up new economic opportunities for the region.
From the outset of the project, MainRoads and the Fitzroy Bridge Alliance have worked closely with local training providers, local government and other response agencies to maximise employment, contracting and partnering opportunities for local people.
“At the time of writing, over 130 locals have been employed on the project, a quarter of total construction hours are attributed to Aboriginal people and 19 Aboriginal-owned businesses have been awarded contracts associated with this job,” the spokesperson said.
“Workers have been involved in a variety of roles including traffic control, operating plant, and bridge labour. “The project team has also assisted individuals seeking to start their own businesses by providing business support, guidance when purchasing machinery and facilitating opportunities to gain experience using this machinery on different elements of the project.
“As the project approaches completion, Main Roads is liaising with other State Government agencies to identify ongoing opportunities for locals who have developed skills and business capacity as a result of the bridge build.” The spokesperson said the new bridge will be six times stronger than the old bridge, as it is designed to withstand a one in 2000-year flood event.
“It will significantly improve the road network in a critical location, providing assurance to the freight industry, tourism operators and others who rely on the road network in the north west of Western Australia. Replacing the single-lane bridge with two lanes will also assist with transport efficiency and improve safety for all road users.”
Flow on effects
As extreme weather events and natural disasters become more frequent, it is paramount to support the development of critical road infrastructure in remote Australia to ensure communities and industries can bounce back.
“The impact of ex-tropical cyclone Ellie in December and January showed the vulnerability of our road network to natural disasters,” the spokesperson said. “Furthermore, the freight industry, tourism operators, logistics providers and local communities rely overwhelmingly on a safe, efficient and resilient road network in remote areas, particularly given the absence of other feasible and economical modes of transportation.
“This project has also demonstrated how infrastructure investment in remote locations can have a positive socioeconomic impact, through the creation of jobs and the circulation of money through the local economy. “In August, The Australian newspaper reported how the community of Fitzroy Crossing had observed a significant reduction in crime and antisocial behaviour due to the opportunities created by the bridge build and other flood recovery efforts.”