Designing For Brownfield Sites – A Young Geotechnical Engineer’s Perspective

Upgrading existing road infrastructure is becoming increasingly common in Sydney. The growing population places increasing demands on existing road infrastructure, requiring upgrades to cope with growing traffic volumes. Some of these upgrades require structures such as retaining walls and bridges. Upgrades sometimes require modifications to existing structures, which further complicates design and construction. Working on ‘brownfield’ sites adds further complexity to the design of both new and existing structures. Site constraints such as limited space, low headroom and both buried and overhead utilities are some of the factors that contribute to the complexity of designing on brownfield sites. Furthermore, sites are usually required to remain open to traffic during investigations and construction. This paper focuses on the methodologies the Author has learnt and adopted to address these challenges to geotechnical work during the site investigation, design and construction phases. Case studies are presented to illustrate some of the challenges and solutions.