An aerial view of what some are calling the largest glass ceiling in the world.
The 2010 World Cup kicked off last week in South Africa, bringing the most-watched sporting event in the world to the African continent for the first time in the tournament’s history. In preparation for the unprecedented swelling of media attention and massive crowds, South Africa has had five new stadiums built, in addition to major renovations done on five others. Among the new stadiums is the architecturally stunning Cape Town Stadium, situated in the posh Green Point neighborhood. Designed by German firm gmp-Architekten, the 68,000 seat stadium showcases a novel design feature: a roof made of 9,000 half-inch thick panels of laminated safety glass, arranged in a ring formation that juts out into the open-air center of the stadium. At 398,265 square-feet, it is, according to Popular Science magazine, the world’s largest glass ceiling.
A mix of enameled and clear safety glass panels shield the audience from the elements, provide shade from the intense overhead sunlight, and keep noise levels down for surrounding communities.
The laminated safety glass panels, akin to the glass used for car windshields, reduce light intensity by about 80% as well as lessening heat dissipation. They can thereby protect spectators from weather extremes, including precipitation, but also allow natural light to filter into the stadium. Furthermore, in connection with an inner layer of diaphanous membrane skin (made of PVB, polyvinyl butyral) the roof prevents the near-riotous levels of noise from cheering soccer fans from escaping through the open center of the stadium and disturbing the surrounding neighborhood.
The view from inside the 70,000-square-foot stadium, the shadows on the field clearly revealing how the roof shields from the sun.
Construction was a technical challenge, requiring the roof to be built at ground level and then raised with 72 cables that tightened the outer and inner layers together. Hidden in between these two layers is the stadium’s public address system and lighting, out of sight of spectators, reflecting an aesthetic of integration and fluidity, together with the transparent glass that, while protecting those inside the stadium, does little to obstruct the vivid blues of the South African sky.
—Lee Gaizak Brooks