The Gateway Upgrade Project is the largest bridge and road project in Queensland’s history. The project includes the refurbishment of the existing Gateway Bridge and the construction of a second Gateway Bridge, including a dedicated pedestrian and cycle way. The Port of Brisbane Motorway interchange will also be upgraded.
Aurecon’s role involved the review of the design packages prepared by the Leighton Abigroup JV for the 12 km of widening of existing dual carriageway, and 7 km of a new six-lane carriageway across derelict and swampy ﬂood-plains. This will provide a connection to both the existing Gateway Motorway and Brisbane Airport, thus relieving congestion on the existing routes.
The challenge was to develop cost-effective design solutions to achieve stringent programme and long-term performance criteria.
Another key challenge included geotechnical issues regarding the performance of high embankments (up to 13 m) on very soft-to-soft alluvial deposits up to 22 m thick (paleochannels) which were created over thousands of years.
The wide range of loading and ground conditions meant that a variety of solutions were needed to achieve the required performance criteria. Aurecon’s review of the design demanded a wide range of technical ﬂuency in terms of design process.
In addition to the earthworks, the project used extensive piling, including large diameter bored piles for the new Gateway Bridge. As part of the design, an extensive borehole investigation and full-scale pile load testing was carried out using Osterberg cells, the first time this technology was used in Queensland. Detailed analysis using alternative software, including Plaxis and ReWard, was then used to evaluate the effect of faulting and uneven bedding on the pile group performance.
The project will deliver many benefits, including safer and easier travel along the Gateway Bridge Motorway, reduced travel time, improved links for business, industry and tourism, easier travel between the Gold and Sunshine Coasts, and improved access to the Australian TradeCoast precinct.