Flooding generated by ex-tropical Cyclone Ellie between December 2022 and January 2023 caused significant damage to the sections of Great Northern Highway at Fitzroy Crossing in the remote Kimberley region of Western Australia.

The Fitzroy River Bridge was significantly damaged along with 500 metres of road – cutting access to Indigenous communities east of the Fitzroy River as well as the East Kimberley and Northern Territory.

Given the critical importance of this bridge to the community and the State and National Road network, Main Roads WA sought to complete a new bridge structure and access roads within the shortest practical timeframe, with the elements that could be impacted by water flow completed before the next wet season.

As a part of the Fitzroy Bridge Alliance with Georgiou and BMD Group, BG&E adopted a streamlined and focused approach to restoring this critical link, with sustainability initiatives targeting four key areas

• Lasting and sustainable social and economic outcomes.
• Working in partnership with the community.
• Resilience – contributing to a stronger Kimberley.
• Making the best use of local resources.

We provided bridge design services for the Fitzroy River Bridge replacement project, which included

• A new two lane traffic bridge over the Fitzroy River.
• Integrating a pedestrian pathway.
• Reconstructing bridge approaches.
• Implementing flood and scour protection.
• Managing the protection and relocation of utility services.
• Flood modelling and hydrology.
• Temporary causeway and access road.

The new bridge is 100 metres longer than its predecessor, at 270 metres long, and twice as wide, at 12.4 metres wide. It is an eight-span continuous bridge with a weathering steel-concrete composite deck. The bridge superstructure was incrementally launched from the western abutment and completed in 32 days.

Blade wall piers with pile caps were installed, and the supporting piles of the bridge substructure were placed significantly deeper than the old piles to accommodate scour in the riverbed during extreme flood events.

The remote location posed a challenge for transporting materials to the site. To best use local resources, the project tracked material inputs and outputs and tested local aggregates for suitability for pavement, concrete and rock protection. This enabled appropriate choices for the project and provided valuable data for future regional projects. Significant reuse of materials was achieved onsite, and surplus material was stockpiled for future projects.

The bridge design and construction methodology maximised local workforce participation, providing employment and business opportunities and transferable skills.

The New Fitzroy River Bridge opened to traffic more than six months ahead of schedule. This project is set to have a lasting and sustainable legacy for the community surrounding Fitzroy Crossing – reconnecting East and West Kimberley and creating skills development and economic opportunities.