Australia Square, Sydney

Australia Square was Sydney's first high-rise office tower. It established new principles in design and construction through its distinctive circular form and the creation of a large public open space at ground level. At the time it was built, 1961-1967, the tower was the world's tallest light-weight concrete building. In 1967 it won the prestigious Sir John Sulman Award from the Royal Australian Institute of Architects.

“The circular form of the 50 storey building was arrived at by a process of elimination, rejecting rectangular solutions which would create narrow canyon-like spaces against surrounding buildings. Better circulation and open plazas resulted.” (Harry Seidler, notes, PXB 237)

The public space is established by a plaza that is set above street level and steps down throughout the site. Usable outdoor space includes seating with trees, sculpture, fountain and outdoor restaurants, all of which are popular with office workers at lunchtime. It is one of the earliest examples of the development of comfortable public open space on private land. Artworks and sculpture by leading international artists are also featured in public areas, including tapestries by famed architect and artist Le Corbusier, and another by Hungarian-born artist Victor Vasarely.

Typical floor (structure) Australia Square, by Harry Seidler & Associates, 1961-1967. Diazo print, by permission of Penelope Seidler AM. PXD 509/1

The circular form of the tower was structurally extremely efficient. The consistency of floor plan, the use of pre-cast façade and in situ construction meant floors could be erected quickly, setting new standards in office tower construction.

The structural system was developed in collaboration with one of the world's leading engineers, Pier Luigi Nervi, and featured technological advances such as patterned ribbing and tapering exterior columns in pre-cast concrete as permanent formwork. The entire façade of the tower was prefabricated in sections under factory conditions, brought to the site and erected by crane.

Australia Square is still regarded as a landmark building in Sydney and an icon of modern Australian architecture. With its radical circular design, usable public space, and its advanced construction techniques for the time, it changed the face of the Sydney CBD and architectural design in Australia.

> View catalogue record for Australia Square, 1961-1967, architectural plans by Harry Seidler & Associates

> Read newscuttings relating to Australia Square, from Harry Seidler's scrapbook