Country:	Australia
Key Area:	Transportation
Services:	Transportation Infrastructure Design

Queensland’s approaching wet season was the catalyst to fast-track the design and approvals for a project to upgrade a large public road bridge, which saw the project completed in two and a half months instead of the more typical six month turnaround.

A private bridge across the Dawson River had historically been used by Cockatoo Coal to transport coal from the Baralaba mine for export, but the low level of the bridge made it prone to flooding.

In the last wet season, interruptions cost Cockatoo Coal around AU$50 million due to their inability to transport product to port. An adjacent public road bridge also sat quite low to the river, and regular flooding of that bridge similarly caused disruption to residents and traffic in the Baralaba region.

Following a period of community consultation, it was agreed that the best solution was to upgrade the existing public access wooden bridge, rather than the private bridge, to enable it to carry both public and coal-related traffic. The bridge approaches and intersections also needed to be modified to cater for heavy vehicles on the public roads.

The upgrade project was a joint venture between the Department of Transport and Main Roads and Cockatoo Coal. Opus and Reed Mining & Energy were asked to prepare a plan detailing a realistic methodology for designing and building the new bridge within the client’s six month timeframe.

The bridge design phase of the project included a geotechnical investigation, hydrology studies, environmental analysis and detailed design. The second phase—detailing the bridge approaches and road intersection works—was also submitted on time and within budget.

The original bridge was 60m long, but its replacement will be 140m long, and 4m higher than the original to provide better flooding immunity. It has also been designed to cope with irregular, larger-scale flooding events.

Opus staff have been permanently on-site for the final phases of the project to provide engineering support, structural inspection and ongoing design advice.

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