Madison Grand Southbank

The challenge.

FSG was engaged to provide geotechnical consulting services to support the redevelopment of the site located at 344 City Road, Southbank into a 39-level residential tower with a multi-level podium and basement.

The site is located in an area of Melbourne characterised by a complex sequence of low strength Quaternary age alluvial deposits overlying a layer of older Tertiary age weathered basalt and sediments. Developing a detailed understanding of the subsurface profile and its variability across the site was critical to providing confidence for footing and basement retention design.

Geotechnical investigations were complicated by limited access being available to the site pre-demolition.

The approach.

FSG undertook a staged investigation, comprising a pre-demolition investigation using low headroom / limited access drilling equipment and a supplementary investigation post-demolition to confirm subsurface conditions across the site.

We also reviewed historic and nearby geotechnical information to better understand potential variability in subsurface conditions around the site and in particular areas where lower strength alluvial deposits could be present that could impact on footing and retention design.

The findings were used to develop a detailed ground model for the proposed development, identify key geotechnical risks for the site and provide informed footing and basement retention design advice.

The outcome.

FSGs work on the project provided the design team with the information required to make informed decisions regarding excavation strategy, footing design and basement retention.

The investigation and subsequent geotechnical assessment confirmed that the proposed building could be supported on shallow pad footings founding in the weathered basalt, providing a practical and cost-effective footing solution for the development. During construction, FSG attended site to confirm footing founding conditions were consistent with design requirements.