Civil construction first
In an Australian-first for a civil construction project of this scale, the first of two new bridges constructed “off-site” has been successfully transported and installed for the $468 million (AU$620 million) Darlington Upgrade Project in South Australia.
The 180 meter-long, 3,000 tonne bridge was built on land between the Southern Expressway and Marion Road, at Bedford Park, over several months and was installed using self-propelled modular transporters (SPMTs) on November 24-25, 2017.
The Darlington Upgrade Project is being delivered by Gateway South on behalf of the South Australian Department of Planning, Transport and Infrastructure. Gateway South is a joint venture between Fulton Hogan and Laing O’Rourke, with Jacobs delivering the design in association with its partners, KBR and SMEC.
An international team has been involved in the engineering design for this complex undertaking, including the Adelaide office of Jacobs as lead bridge designer, along with colleagues in Chicago. The team developed a detailed analysis of more than 150 load cases of various vertical and twist scenarios for the SPMT move to determine the allowable limits during the move.
The team defined the deflection and stress limits – which Gateway South and its subcontractor, Sarens, utilized during the move – and supported site engineers by monitoring remotely from the U.S. during the move.
The innovative off-line bridge construction method was adopted, rather than traditional bridge construction practices, as it significantly reduces traffic and community impacts. Only a single weekend closure was required to install the pre-assembled bridge, alleviating the need for multiple major road closures. Additional design features included double composite action, precast deck panels with shear stud pockets and precast barriers.
The successful bridge move was completed well ahead of schedule.