1 Bligh Street

March 1, 2012

Informed by the architects’ social and cultural intent, Australia’s first ‘green skyscraper’ is an outstanding, design-led building with deep commercial value.

At the 2002 International Union of Architects Conference in Berlin, German architect Christoph Ingenhoven gave a powerful talk about architecture. It was in effect a mini-manifesto and received a standing ovation. Ingenhoven, who had flown in from a summer holiday on the beach with his family, structured his talk around the explanation he gave to his young children about the importance of architecture and “why daddy had to leave”. He spoke with passion about our “small blue planet” with its finite resources, his approach of “enthusiastic pragmatism”, and his opinions that “modernism is no style”, “that architecture is not a performing art but a social art”, “that we should make everything as simple as possible, but not simpler”, and that beauty arises from necessity, although it is “very rarely as successful as nature”.

The full-height atrium at 1 Bligh Street


Fast forward to 2006. Ingenhoven, in association with Architectus, win the City of Sydney competition for 1 Bligh Street, a new office tower for property groups DEXUS and Cbus. Now complete, it has retained the author’s integrity, possibly unlike most other Sydney buildings by international architects, and can be seen as the built manifestation of Ingenhoven’s ideals.

Glass lifts animate the central atrium


1 Bligh Street’s elliptical geometry elegantly resolves the site’s urban condition at the confluence of two city grids. The ellipse is rotated on its site to address views to – and, importantly, from – the harbour, simultaneously resolving the urban condition and maximising the building’s commercial value.

Conceived as a ‘solitaire’ – detached from its surroundings – it stands as an object located in an enlarged conception of Farrer Place, defined by the historic Education and Lands Department Building. Elevated 16 metres above the sloping ground plane, it allows public movement through and around the site, which is celebrated by a generous sweep of curving steps facing north towards Farrer Place. On the O’Connell Street frontage, a childcare centre has been ingeniously inserted under the lobby, with an outdoor play area enclosed in a draped screen of metal mesh.

Office lobby and cafe space


At the top of the steps is the office lobby with a café, which is naturally ventilated by frameless glass louvres and large, pivoting glass doors, opening up the space to Sydney’s temperate climate. Fresh air ventilates the lobby and up through the building’s lung – the full-height atrium. This heart-shaped space is located between two split cores located on the southern, non-view side. Glass lifts animate the space with their vertical movement, and connecting the lift cores are naturally ventilated breakout spaces, which, detached from the facade, appear to ‘float’ within the atrium.

The north-facing office area is a large, contiguous space well-suited to current organisational needs of communication and connectivity. Structurally, the floor plate has a highly efficient, 16-metre centre span with six-metre cantilevers that dramatically free the glass from obstructions. The curved floor plate is described by Architectus’ Ray Brown as a “rectangular space with a curved edge”, responding to market demand for rectangular spaces.

Public spaces surround the building's entrance


The building is wrapped in a highly transparent double-skin facade that has evolved from Ingenhoven’s RWE Headquarters building in Essen, Germany. It consists of an inner sealed skin of double-glazed units and a ventilated outer skin of clear glass, with a 900-millimetre cavity containing mechanically operated louvre blinds that track and respond to the sun’s movement around the building. The facade is vented on a floor-by-floor basis and was originally conceived to allow natural ventilation for the building. The use of perimeter chilled beams and a commercial decision has prevented this, but, as the architects note, it can be adopted by tenants in the future.

The building’s scale is broken in the middle by a large outdoor terrace incised into the floor plate at the lift transfer level. This space has been embraced by Clayton Utz as its reception floor, providing it with potentially the most spectacular and unique reception of any legal firm in the city. The terrace also cleverly conceals the air intake for the air handling plant above, which is wrapped in a glass skin and fully visible within the building.

At the top of the building, the inner glass skin peels away, creating a large outdoor timber terrace planted with banksia trees. The roof plant has been artfully resolved – not without considerable angst, according to the architects – to create the building’s fifth elevation, upon which taller surrounding buildings look down.

The timber terrace at the top of the building


A solar array on the roof is part of the six-star Green Star strategy that also includes a trigeneration plant. A maximum of five points for innovation (out of a possible five) were awarded to this building: for the naturally ventilated double skin, the hybrid trigeneration plant using gas-fired power generation, absorption chillers and solar cooling, the tempered environment (applying different comfort criteria), the full-height, naturally ventilated atrium and the reduced building embodied energy.

The resolution and incredible attention to detail is a credit to both Architectus and Ingenhoven, a highly successful collaboration between two offices, each prepared to “do whatever it takes”. A great success of the building is that it has been completed in a manner faithful to the competition design, thanks to the developers, DEXUS and Cbus, and builder Grocon.

The elliptical form of 1 Bligh Street in central Sydney


Comparing 1 Bligh Street to other nearby buildings by international ‘starchitects’, we see that it is probably the first genuine product of international significance to be realised in Sydney. Notably, Ingenhoven is the first international architect to attend the opening of his own building in Sydney. Let’s hope that the building’s success will further inspire Sydney developers to allow buildings to be design led, thereby achieving outstanding results that translate directly into commercial value.

Philip Vivian is a director of Bates Smart, the practice responsible for the Clayton Utz fitout in 1 Bligh Street.

Watch the Design Conversations video on 1 Bligh Street, with Philip Vivian, Christoph Ingenhoven and Ray Brown.

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