Optus Stadium

Crown Jewel

Underpinned by a voluminous yet visually lightweight structure made from approximately 7500 tonnes of BlueScope steel, Perth’s Optus Stadium has rapidly fulfilled the design vision for a distinctly Western Australian, world-class sports and entertainment facility.

Since opening in late 2017, Optus stadium has garnered a swag of awards, key amongst which was the 2018 Australian Institute of Architects National COLORBOND^® Award for Steel Architecture and the National Award for Public Architecture – the former described by the jury as “a compelling and worthy contribution to Australia’s steel architecture tradition.”

In many ways, steel is the ultimate hero of the project. “The steelwork gives the building its aesthetic appeal and character,” says Hyett. “Steel is the most wonderful material for architects, it combines incredible strength within relatively small sections and it’s also something which you can easily form and shape.

“The roof of that building, with the cantilevered steel trusses tied at the back and the way in which that roof is working, structurally, is expressed in its appearance. The combination of the steel and the fabric has given the most incredibly light feel to it,” he says.

BlueScope supplied all of the primary steelwork – 4500 tonnes of welded beams and columns and 3000 tonnes of XLERPLATE^® steel - via WA distributors, InfraBuild. Another 1350 tonnes of steel decking was supplied by Fielders and LYSAGHT^®.

The architects say steel was integral to the construction program of the five-level superstructure and the ambitious design performance requirements of the ‘floating’ roof structure. Featuring more than 15,000 fabricated steel components, the works included the installation of 50 major structural trusses that support the tensile fabric roof canopy that shelters up to 85 percent of spectators.

The architectural and structural geometry of the roof was also developed to address an ambitious program requiring steel pre-fabrication, as well as transportation and erection challenges. The cleverly designed pin-joint system with tolerances to absorb differential movements across the structure below, and to allow fine-tuning to ensure alignment of the leading edge, results in a stunning and efficient halo roof solution.

For Dean, it was important that materials were expressed honestly - with all primary steel structure coloured white, and a grey secondary steel structure - to create a decipherable building lexicon.

“As a muse, steel’s malleable, adaptable form has been interrogated extensively, from its piled structure to help overcome difficult ground conditions, large spans in the roof trusses for obstruction-free views, feature columns, beams  and seating bowl rakers to the dramatic geometry of the pedestrian arbour,” Dean says.

“The generous spans in the trusses allowed us to get large elements, such as function rooms, underneath the seating bowl without transferring any structural columns out,” he continues. In addition, the steel columns facilitated consolidated services to minimise costs and keep fans closer to the field-of-play, rather than lifting them further away from the action.

“There was a lot of engineering and collaborative work with Arup and Multiplex to refine the design of the steel frame members, and particularly the truss,” says Batchelor, who describes the finely detailed pivot-knuckle joint designed into the truss base which allowed the trusses to be placed relatively simply – mitigating the need to work at height as much as possible.

The steel trusses themselves were prefabricated by Civmec in nearby Hendersen, then transported to site where all the cladding elements, including the fabric roof modules, were added and craned up as a single element. “At the height of construction we had nine trusses down on the ground being assembled while one was being lifted into place, it was a really interesting construction program,” says Batchelor.

The construction and erection methodology was a key innovation, agrees Dean. With construction proceeding with basement works at one end and roof works at the other, the cantilevered, triangular trusses were designed to free-stand after three bays were erected. “The roof had to be free-standing because it was never complete until the last bay went together,” says Dean.

The way the design was transferred into fabrication is, for Dean, an under-recognised aspect to be celebrated. “The fabricators went through hell and high water over an 18-month period to deliver the project on time. It’s no easy feat, particularly with a fast-tracked project, and a constantly evolving design.”

Of his experience in Perth, Hyett says “On this occasion we were able to fuse the ability and the commitment of Australians to good architecture with the Australian love of sport. It was a wonderful marriage and I was very happy to be there in the middle.”

What matters about the stadium for Dean is that the architects have created a memorable Western Australian emblem, and in turn have set a new benchmark for what people in WA expect from these kinds of projects: “Usually you say there have been compromises, but this project got better and richer because of peoples’ commitments. It was a career-defining moment for everyone involved.