The Greenpoint stadium is set to host the semi-finals of the 2010 World Cup this summer, yet post-World Cup the structure will become a permanent feature in Cape Town, presenting rugby and football games, concerts and other large-scale celebrations. In order to allow for the mammoth influx of supporters this summer, temporary seating has been installed on the main and opposite side of the upper-most tier, increasing capacity from 55,000 to 68,000. Once the tournament is over, this additional space can be converted into suites and club rooms, increasing the amount of income-generating facilities to secure the future profitability of the stadium. Currently, of the 68,000 seats in the stadium, 2,400 are business seats and 2,500 are in private suites.
One of the main design dilemmas on the Greenpoint project arose after concerned locals feared that the new build would have a detrimental effect on their existing views of the city from Cape Town’s hilly topography. As such, the decision was made to harness new construction techniques for the roof of the stadium and create a hybrid between a suspension cable structure and a truss-girder system. Steel truss girders were placed upon load bearing cables to create a roof volume that is clad on two sides. The whole upper, pitched roof surface of a total surface of approximately 36,000 sq m is covered with safety glass. The inner 16m are clear-glazed to allow as much sunlight as possible to fall onto the pitch, whereas the rest of the glass is enamelled, which helps to lower heat dissipation underneath the roof and absorbs approximately 80% of the incoming light. Architects originally wanted to construct the lowest of the three tiers underground to reduce the height and visual impact of the stadium, however the hard rock formation on the site (at the foot of Signal Hill) prevented this approach. Instead, an elevated podium of approximately 5 hectares was introduced, reducing the visual impact of the build by 25%.
Much consideration has been paid to the visual effect of the Greenpoint Stadium on the existing location, ensuring that the vast structure doesn’t dominate or irreversibly alter the natural landscape. Nowhere is this more apparent that in the facade design - ‘an abstract, linearly arrange membrane construction’. In an attempt to transform the building into a permanent sculpture, the form is shrouded in a semi-transparent, light-coloured glass fabric with a soft silver coating. Whilst this material will absorb and reflect the ever-changing weather conditions, (white and light during bright sunlight and murky grey on a stormy winter day) as the sun sets the stadium will be clothed in a reddish glow, whilst at night it will appear to shine ‘light a paper lantern’. In the quest to retain Cape Town’s existing architectural character, the numerous architects and designers involved in this project have managed to put their own subtle stamp on this popular, cosmopolitan city.