Architecture: Why Sydney is going for bold

Sydney plans to better Barcelona in the scope of its urban renaissance sparked by next year's Olympic Games. It will be one of the most ambitious design projects ever in the southern hemisphere.

One of the biggest urban regeneration programmes this century has been triggered by the Sydney 2000 Olympic Games, which is to be staged on 750ha of formerly polluted industrial wasteland.

Everything for the Olympic Games is on steroids (except the athletes, of course). "Think big, then double it," was the idea behind the design of what the architects call "the sheds" - the world's largest Olympic stadium.

The stadium by Bligh Lobb seats 110,000; the Olympic Park station by Ken Maher & Hassel Architects has to transport 50,000 commuters at peak times. Clustered at Homebush Bay, 15km outside Sydney, are exhibition halls, archery parks, tennis courts and an equestrian centre, housed in quick-rise, simple, open sheds that breathe.

The architects all claim to have freed their building forms from any cultural preconceptions, but to many observers those big sheds, many of them open-ended, are in the sheep-shearing vernacular but sized like Valhalla. Only the skilful manipulation of light within transforms them, inside and out. The architects have cut out panels and snipped gussets and shadow gaps into their sheds to let the sky and clouds play on them in the most enlightened way. Set among the sheds are hotels and housing, cinemas and shops planted in the Millennium Parklands, which will be completed by 2010.

Everyone talks of the indecent haste with which contractors have created the sporting complex, from the day in 1995 that Sydney won the race to host the games. Such haste is usually accompanied with compromises, but, as a chunk of urban planning, the construction of the Sydney Olympic Games site is one of the most ambitious urban design projects ever mounted in the southern hemisphere.

Exactly one year from the opening ceremony of the Sydney 2000 Olympic Games, an exhibition at the Royal Institute of British Architects shows the transformation of Sydney into the host city of the games. Normally static presentations of pictures and scale models, drawings and plans have a dynamism that reveals the peculiar fascination designing for sport offers architects. They may be sheds, but they are muscular and rhythmic with a fluid movement.

The Australians have used the games as a catalyst for urban regeneration with a major development programme similar to Barcelona, where the 1992 Olympic Games were the catalyst for the regeneration and renaissance of the city.

Landscaping and planting street furniture on this vast Sydney site is the task of Tonkin Zulaikha Architects; which describes it as "designing a suite of urban elements to glue together". First, it paved the "great rubbish dump" of the site, then created concrete walls reminiscent of the Mexican architect Luis Barragan's monumental slabs, hovering in the landscape. The picnic areas dotted about the square consist of slabs of concrete with platforms cantilevered to form benches and tables.

Olympic Plaza, the third biggest square in the world after Tiananmen and Red Square, is planted with a forest of lighting towers. Towering like triffids raised in Gro-bags, these 30m-high light gantries stalk through the Olympic Games. They lean away from the gravitational pull of the gigantic arena and provide shade by day under a giant arm angled to collect sunshine on panels, and store it. "Very War of the Worlds," its designer Peter Tonkin admits. At night, light beams up from the base to its jewel-like triffid head, faceted like a fencing mask and mirrored to reflect and diffuse light, bouncing it back on to the plaza. Each solar-powered panel measures 4m by 4m, which creates a sizeable shade area when banked along the arms.

Peter Tonkin hopes that the lighting towers will become the universal symbol of the Olympics 2000. "Certainly, they're a demonstration of the environmental agenda," he says. Equally certainly, the opera house that put Sydney on the map won't do as a symbol for the games. Barcelona had Corbi, that foxy little dog drawn by Javier Mariscal. While it is true these towers won't make such loveable souvenirs, as a lighting system they are brilliant.

Key to the design is its longevity, and the site incorporates different uses such as housing, parklands, offices and shops. Fundamental to urban planning is the infrastructure.

To cut down on cars and the impact on the landscape of miles of carpark, a railway track links Sydney with Homebush, arriving at Olympic Park Station. For such an egalitarian country, Australian public transport systems are archaic or non-existent, and this rail link will be a showpiece. From the very earliest railway stations, buildings for transport, including airports, have acted as gateways to cities as well as benchmarks of technological and social progress. Olympic Park railway station, 120m-long in steel and timber with 45m-wide trusses, will have to carry 10,000 people a day.

Railway stations, which are no more than sheds covering tracks, on such a gigantic scale need an interesting roof. The architect Ken Maher created a roof-line that rises and falls in hips and valleys like dinosaur scales.

The RIBA exhibition includes a slide of a serrated leaf to explain the five leaves of the barrel vault that naturally ventilate the building. This roof-line lets in light through cuts, changing its silhouette by the hour. What is a void by day fills up with light to become an opaque block by night. "It's one of the very few public buildings that reverses solid mass and volume by night," says Maher. It is a crafted building with a simple concrete pre-cast frame and a light steel canopy. The roof lands lightly upon ribs, with light shafts running the length of the station so that the sky is always visible.

"We looked at the turn-of-the-century railways with their sense of space and light and drew on those traditions to create a station with a turnaround for two trains a minute," Maher explains, showing a slide of Sydney's streets jammed with 47,445 joggers for the marathon fun run. "All those runners and only one way to go. That's the number of people to put through the rail station daily during the Olympics."