Essentially rectangular in plan the stadium uses the bevelled corners around the pitch to shape an oval roof whose petal shaped girders seem to unfurl upwards and out over the seating from a two storey colonnaded glazed gallery that runs fully around to provide circulation, services and hospitality. The unique design of the roof has been compared to a coral shell and a sunflower. It results from the alternating arrangement of girders clad with aluminium and areas of PTFE membrane stretched between them. The elevated ridge of the external top chord expresses and adds drama to the structure whilst the intermediate PTFE membrane zones are separated into two fields by a valley cable, producing an alternating pattern of rib shapes and hollows that mirror the interchange of materials. The girders form triple-parabolas whose aluminium cladding is perforated in the lower sections where they reach down to provide elements of the exterior skin to the circulation gallery. This helps provide the necessary sun screening whilst still allowing varying degrees of transparency which afford VIPs and circulation areas a spectacular view of the surrounding park, the lake and the ocean.
The result is a very distinctive structure that benefits from its unusual low-rise lakeside setting to add a very modern element to a rather tired cityscape. Unlike Soccer City in Johannesburg or Mbombela Stadium in Nelspruit, the design does not take inspiration from the local vernacular or use locally-sourced materials. Indeed, the only truly local reference is the building’s name which is somewhat laboriously incorporated into the circulation area: “With a graphic use of sayings by Nelson Mandela, the gallery (it is over 700m long) is interpreted as a ‘long walk’ in the sense of sporting ambition and Fair Play among equals.” According to the architects the building is iconic both by day when ‘the white roof rests on the fair-faced concrete of the primary structure like a lightweight garland of petals’ and at night when ‘with its large backlit membrane areas, it looks like a huge storm lamp’. In terms of the sustainability which the ecosymbolic design inherently suggests ‘the geometry of the roof is tailored to local conditions, and protects the crowd not only from the sun but particularly from the frequent strong winds’. The PTFE membrane zones also allow natural daylight and ventilation. In addition the site was partly chosen for its proximity to the city’s port in order to facilitate the transportation of materials from abroad.
It is perhaps appropriate that in such a heavily industrial setting the new Nelson Mandela Bay Stadium should evoke floral forms that seem to suggest not only a brighter, more sustainable future but also the city’s hope that it’s somewhat surprising decision to build a new stadium will bear fruit. The choice of a central but sparse and undeveloped site between the sea and the North End Lake confirms the building’s regenerative intent. And this is reflected in the architecture; according to gmp Architects who led the design consortium: “The stadium springs like a flower from the ground, offering a unique image with its reflection in the water.”