Country:	Australia
Key Area:	Buildings
Services:	Transportation Planning & Engineering

The scale of the flooding in Queensland during December 2010 and January 2011 was unprecedented.  Three quarters of the entire State was declared a disaster zone, and water inundation caused significant damage to physical infrastructure, including road and rail networks, buildings and communication links.  9000 km of Queensland’s State-controlled highways were damaged, along with a significant proportion of the State’s local authority network.

The Queensland Government has set up a central programme, managed by the Department of Transport and Main Roads, for road repair across the State.  This body has contracted project management, design, procurement and construction to a final pool of twelve suppliers.  Opus has partnered with Leighton Contractors and Arup, and the consortium has been commissioned to repair 345 km of road in the Mackay area and 330 km around Bundaberg.  The combined reconstruction budget is approximately AU$900 million.

With quarry materials in high demand throughout the State, leading to shortages and delays in supply, Opus has trialled novel reconstruction methods on low volume roads - with considerable success.  In the past for shoulder sealing, a ‘bottom-up’ approach was normal: excavating the shoulder of the road and replacing it with new materials.  Now, because the high water table makes subgrade materials soft and wet, top-down methods have been developed instead.  These work by carrying out in-situ stabilisation, mixing lime to reduce the moisture content of the soil and improve its plasticity and then mixing cement with the modified materials to further improve their mechanical and interlock properties.

The extent of the damage across Queensland’s roading networks means the reconstruction project will take some three years to complete.  However, in addition to the longer-term outcome of better roads for the travelling public, the project is already achieving closer working relationships between Opus, the client and other consortium members, as well as new and innovative network reconstruction solutions.

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