New kid on the block

For the final building in a billion-dollar, inner-city redevelopment project, coming in last invariably poses a few restrictions in terms of both the design and construction.

The 52 Goulburn project, originally known as Latitude East, is the last building to be constructed in the Multiplex Group's World Square precinct one of the most significant urban regeneration projects ever undertaken in the Sydney CBD. As a consequence, the design of 52 Goulburn was strongly influenced by the existing landmark Ernst & Young Centre and 50 Goulburn high-rise. It was also influenced by the need to retain the existing eight-storey underground car park and low-rise retail centre on site, both of which needed to remain fully operational throughout the construction.

Architect Stuart Harman of Crone Partners Architecture Studios says the design process of raising a building out of the remnant footprint of previous developments was particularly challenging for both the architects and Multiplex, which also built and project managed the site.

"The building had to enhance the spatial dynamics of the World Square precinct, and the visual identity of the site, particularly the corner of Pitt and Goulburn Streets," he says. "And because of the existing retail and plant facilities, we needed to articulate an entrance to a lobby that was three floors up from street level."

Harman describes the resulting design as a composition of simple forms that hovers above the existing retail podium, and contrasts with the more complex nature of the adjacent buildings.

"Two large forms straddling a 10-storey atrium are treated as restrained boxes that balance the more detailed and refined expression of the atrium," he says.

The exterior is highlighted by a subtly changing series of facade treatments, including bands of black and white designed to accentuate the horizontal a reference to the heavy pedestrian and vehicular movement around the intersection. In addition, extruded rectangular architectural frames staggered up the height of the Pitt Street facade create a visual widening of this corner at the lower levels. Towards the opposite end of this facade, the treatment is more constant, with dark-grey horizontal spandrel panels and glazing.

The main entrance, in Goulburn Street, sits beneath the recessed, full-height glazed strip that suggests the atrium space within. The glazing extends down to the retail space, breaking the solid nature of the podium to form the entrance to the building.

"It was important to create a sense of arrival we needed to entice people up the long escalators to the lobby," says Harman. "A commissioned art work by Sarah Robson is particularly successful at helping to visually link these spaces. The building was also designed so that it is possible, from street level, to look up the escalators and catch a glimpse of the sky through the glazed atrium roof."

A simple, yet innovative atrium design fulfils the client brief on a number of levels. It delivers large amounts of natural light while still allowing large office floor plates approximately 2500m² of net lettable area. In addition, with its glass lift enclosures and glazed stairwell, the atrium provides a sense of transparency that enhances visual communication.

"People can see each other as they move through the building," says Harman. "The design highlights the circulation areas, both horizontally and vertically, which helps to animate the space. Similarly, the exposed steel lift structure makes the space very dynamic."

A rectangular floating light fixture above the atrium seating area helps to bring a human scale to the space, creating a sense of intimacy.

Harman says the building was designed to achieve a 4.5 Star ABGR energy rating. Consequently the project involved a number of ESD initiatives. Building energy simulations were used to optimise the engineering designs and reduce consumption. Detailed modelling of the glass roof and building facade was also undertaken, to select a system that would provide very high levels of natural light, while minimising solar gain.

The building incorporates high-efficiency variable speed drive chillers, pumps and fans that reduce electrical demand during non-peak periods. Smart building control systems include outside-air economy cycles.

Energy-efficient light fittings are combined with daylight sensors and the dimming of perimeter zone light fittings when adequate natural light is available. Motion sensors activate lighting in less frequently used areas.

The building also incorporates a comprehensive metering system that monitors the building operation so adjustments can be made to ensure the target rating in achieved in practice.

Gary Bowtell, Multiplex Developments director, says the development of World Square reflects the success of the company's integrated property model.

"All of our operating divisions Constructions, Developments, Facilities Management and the funds management division, Multiplex Capital have played integral roles. Building 52 Goulburn within an operating precinct and above a fully functioning retail centre and car park required an enormous amount of planning, and innovative construction solutions."

Story by: Colleen Hawkes