Green point stadium

Engineering the arena

When the 2010 FIFA World Cup was awarded to South Africa, it was a momentous point in the history of football. With 204 countries involved from the initial qualifying stage, it was the sporting event with the most national competitors. It'also meant that it would be the first time that the World Cup was hosted on African soil.

After the partying died down, it became apparent that the country faced a massive challenge to create the infrastructure needed to support the tournament. At the top of the list stood the challenge of creating five new stadiums at a construction cost of over eight billion rand, and all with an unmissable deadline.

'There's definitely extra pressure because it's the World Cup,' admits Ian McWilliam, WSP Group's lead engineer for electronics on the Cape Town Stadium. 'The deadlines for the World Cup are non-negotiable and these guys don't take prisoners. This was by far the largest project I've worked on. I don't think anyone on the team has worked on a project of this size. We've done hotels and worked on the Victoria and Alfred Waterfront, so we've been exposed to a wide range of jobs but this one encapsulates every single electronic you can think of, so it's quite a challenge.'

To appreciate the wider picture of how complex it has been to create five new arenas, you only need to look at the individual picture of the Cape Town Stadium. Some 68,000 people will cram into the ground to watch the five group games, a second round game, a quarter-final and a semi-final. The ground has 892 smoke detectors, 200 CCTV cameras, 350km of Cat 6 copper cabling and 124 PA speakers. Neither is it a case of just plonking a new stadium in the middle of the city. The infrastructure that supports it all needs to be in place to make sure it is a success.

Outside the ground, a new electrical substation at Green Point has been built to ensure enough power for the stadium and surrounding area. Over six billion rand has been set aside by national and provincial government to upgrade public transport and 1.9 billion rand has been budgeted to improve Cape Town's transport infrastructure. The effect of the tournament should be felt nationally too, as 1.2 billion rand is being spent on upgrading Cape Town International Airport to cope with the increasing amount of traffic and the anticipated visitors.

Lorraine Gerrans, manager of Green Goals - the environmental programme for the World Cup in Cape Town - says that one of the key goals was to make sure that the stadium and the World Cup would leave a great green legacy, such as a huge new 12.5ha public park, biodiversity garden and environmental education centre.

Eco-friendly stadium

'There is international recognition now that these sorts of events can have such huge environmental impact, because people travel to them and contribute to carbon emissions. When they arrive, they use electricity and water, which are scarce resources and which generate waste. So, in terms of just managing the impact of those numbers of people, it is important to make sure that we plan carefully.

'All of these things were considered very soon after Cape Town was awarded host-city status. When the planning started, one of the imperatives for the design of the stadium was to make it as environmentally friendly as possible. Of course, energy and water saving are the two most important factors there. So the design, the orientation, some of the materials that have been chosen, the technologies that have gone into the stadium, even something relatively simple, like rainwater harvesting, all had to be planned right from the early stages of conceptual design.'

Cape Town faced two very specific engineering challenges when it came to construction. The first was that the initial plan to sink the stadium and reduce the visual impact - it stands in the shadows of the world-famous Table Mountain, after all - was hampered when the geology of the area worked against them. 'We couldn't sink the stadium as deep into the ground as we would have liked, because we hit bedrock at about 1.5m down into the excavation,' says Gerrans. 'So the design of the stadium and the fibre glass cladding on the outside, to a degree, was in response to the fact that we couldn't excavate and the stadium is actually standing quite a bit higher out of the ground than we would have liked in this position.'

This inability to sink the stadium combined with the unique geography of the area created another challenge. Cape Town is notorious for the south-easterly wind that in summer travels down the slope of Table Mountain, and Gerrans says this had far-reaching impacts on the stadium design. 'We needed to understand what forces the wind would exert. It's a huge structure, and so we had to do a wind-tunnel test. The design was adapted as a result of the tests. The roof is quite an engineering feat; it is actually hanging from the outside from a compression ring and hangs into the bowl; it is weighed down by glass, as the wind tunnel tests showed that the force wants to suck the roof out rather than push it down, so we are weighing it down with glass panels to make sure that it stays in place!'

For McWilliams, who was responsible for seeing that the stadium's many complex electronics all worked in harmony, it was again the scale of the project that proved the biggest test. 'Coordinating services has been a real test because everyone goes away and does their work and then comes together and tries to coordinate it, but it never works very well - there are always clashes. The way we tried to manage that was by weekly coordination meetings, at which we put the latest coordinating services on the table and worked through the clashes. From my point of view the hardest part of the electronics was making sure that all the third-party systems had to integrate. I was nervous about it before, but we've put in a lot of work and I'm feeling very confident now.'

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