Bridges

The Citywest Link Flyover Bridge forms part of the Rozelle Interchange project and Sydney’s WestConnex Motorway system, connecting the CBD to Sydney’s western suburbs. The bridge provides a grade-separated flyover for traffic turning right from The Crescent into the Citywest Link and has six spans and an overall length of 235 m. The structure comprises a single steel box girder on a 68.5 m plan radius and a curved vertical alignment. It spans over 10 traffic lanes, two other low-level bridges carrying traffic over local waterways, and a plethora of major utilities.

The main challenges in the design and construction of the Rozelle flyover included the erection of the steel box girders without disruption to the traffic below and without overstressing the low-level bridges with crane outrigger loads. The solution adopted the incremental launch method of construction with prefabricated steel box girder sections assembled on an elevated frame at the southern end and launched out over the traffic using a launch carriage system driven by hydraulic rams.

While the incremental launch method is not new, this bridge utilised several innovative ideas to achieve a unique and safe solution. This included launching the steel boxes on a very tight radius with the concrete deck and parapets in place, varying the deck thickness to partially correct the deflected deck profile and the use of a specialised launch carriage system in the erection process. The bridge was successfully completed and opened to traffic in late 2023.