Engineers Australia

Alliance Enhances Geotechnical Outcomes Port Of Brisbane Seawall

Jay Ameratunga, Peter Boyle and Zen Ng

Abstract

One of the largest infrastructure projects handled by Port of Brisbane Pty Ltd (formerly Port of Brisbane Corporation) in the last two decades is the construction of a 4.6km long seawall extending 1.8km into Moreton Bay. The perimeter seawall constructed encloses an area of 230 hectares immediately north-east of the current Port area. The area contained by the wall is being reclaimed in a progressive manner and currently 40% has been fully reclaimed and a further 20% partially reclaimed.

The Future Port Expansion (FPE) seawall was designed and constructed by an Alliance comprising Coffey Geosciences (Geotechnical Consultant), Leighton Contractors (Contractor), Parsons Brinckerhoff Australia (Civil Consultant) and WBM Oceanics (Hydraulic Consultant) along with the Client, Port of Brisbane Corporation (PBC), a semi-government organisation. After studying several delivery methods, the Alliance delivery method was adopted by PBC to best meet the potential risks associated with the construction of the seawall on a site underlain by more than 30m of deep soft compressible soils and concerns over impacts of construction on the sensitive environment of the adjacent Moreton Bay Marine Park which surrounds the site. The complexity associated with the project also involved the variable water depth to the seabed, significant tidal variations over 24 hours, weather conditions, timelines and turbidity issues related to construction. From Day 1, the Alliance committed to risk management related to geotechnical and environmental issues which led to several innovative solutions and outcomes. The positive outcomes achieved could be directly related to the collaboration between a semi-government organisation, a major contractor and several consultants through the Alliance delivery mechanism which helped to streamline the design and construction work and removed the inflexibility usually associated with other contracted forms of project delivery.