SMEC was engaged by the South Australian Department of Planning, Transport and Infrastructure as part of the Gateway South Consortium to design and construct the USD 441 million Darlington Upgrade Project in Adelaide, Australia.
The Darlington Road Upgrade Project comprises the construction of 3km of free-flow motorway (with a maximum of five lanes in each direction), nine overbridges and at grade side surface roads. The project forms part of the Adelaide North-South Corridor Upgrade which is the centerpiece of South Australia’s transport infrastructure strategy. It is arguably the most complex road project ever undertaken in South Australia with the upgrade taking place along the busiest road in the state within a heavily developed environment. Traffic makeup and volume combined with mixed residential, industrial, institutional and commercial land use along the corridor meant that the upgrade required clever and innovative engineering to deal with the complexity and constraints of such a dense brownfield environment.
Together with its Joint Venture Partners, SMEC was responsible for design coordination, traffic modelling, geotechnical investigations, traffic engineering, bridge and road design, drainage and Intelligent Transportation System (ITS) design.
- Technical Area:
- Department of Transport, Planning and Infrastructure
Darlington’s Big Bridge is 180m long and weighs over 3000 tonnes. Built offsite, it was manoeuvred into final position using self-propelled modular transporters (SPMTs) at a speed of around 100 metres per hour.
The SMEC team managed and successfully overcame many challenges, including the difficult geotechnical conditions which led to the use of unsaturated soil modelling and detailed traffic modelling in support of construction staging to ensure traffic flows at peak periods.
The interconnectivity of each section of the scheme was another challenge. At each stage, we had to consider the impacts not only in the current stage but also future stages, as well as consider ramifications for construction methodology. SMEC’s knowledge of traffic movements on site and its understanding of minimum requirements were critical in ensuring that proposed staging plans were feasible and that any issues were detected early so that they could either be avoided or addressed.
In an Australian-first for a civil construction project of this scale, three new bridges were constructed ‘off-site’ and moved into position – a unique construction methodology approach.
SMEC’s team has been commended and acknowledged as providing a “higher level of service to traffic movements than would otherwise be available resulting in improved flows during construction.”