Condor Tower

Various speakers

Condor Tower is a residential development located on St Georges T errace opposite the Perth Concert Hall. The existing site comprised of a nine storey office building (originally named The Oakleigh Building) with a vacant site behind, facing Hay Street. The vacant site had previously been partly developed, with installation of diaphragm walls and excavation to about 7 m depth, before being abandoned. The project involved adding nineteen storeys onto part of the existing nine storey building and constructing a new eleven storey structure facing Hay Street.

Some of the structural and geotechnical challenges overcome in constructing nineteen storeys of new on top of nine storeys of old as well as development of the previously abandoned excavation included:

• Strengthening of the foundation system.
• Controlling settlements within the foundation system.
• Constructing new foundations and installing piles within an existing basement with limited headroom.
• Underpinning and piling used to develop the previously abandoned strut-supported excavation.
• Strengthening the existing structure.
• Transferring lateral loads through the existing structure.
• Construction techniques involving new to old elements.

Managing the risks associated with such a demanding and challenging project also contributed to a successful outcome. These included assessing:

• Settlement of the existing and adjacent structures and properties.
• The effect of changing water table levels on surrounding structures.
• The interaction and load sharing behaviour of new concrete and old concrete within the existing structure.

This technical session will be presented by three speakers, each discussing specific aspects of the project that were critical in meeting these challenges.

Arthur Psaltis will discuss the design and construction aspects of the project.

Ian Smith will outline the geotechnical and foundation solutions adopted.

Professor Andrew Deeks will provide an overview of the research that has been undertaken in the behaviour between the existing and new concrete elements of the building.

Engineers Australia members participating in AGS technical sessions can record attendance on their personal CPD logs. Members should refer to Engineers Australia CPD policy for details on CPD types, requirements and auditing guidelines.