The stadiums being built or enhanced for the 2010 FIFA World Cup emerged as a key feature in the Southern African Institute of Steel Construction’s (SAISC’s) 2009 Steel Awards, earlier this month, which ultimately saw Durban’s Moses Mabhida stadium being declared the overall winner.
The iconic stadium, named after the late trade unionist and former general secretary of the South African Communist Party, was hailed by the judges as “a formidable and awe-inspiring work of genius, of which South Africans and the world will be proud for generations to come”.
As with most iconic stadiums, the central engineering and aesthe- tic element of the Moses Mabhida stadium is its roof structure, which consists of five structural elements, including a major steel arch, supporting cables, a membrane roof and a steel compression ring resting on steel columns.
The 350-m-long and 106-m- high free-span arch, consisting of 56,5-m × 5-m steel hollow boxes and weighing 3 500 t, was fabricated in Germany and shipped to Durban in sections. The magni- tude of this arch is such that a cable car will carry visitors up the middle of it, to a viewing platform on its north side, while the south side will have a 550-step adventure walk.
The compression ring, the structure to which the roof elements are linked, is supported on a series of vertical and inclined structural steel façade columns comprising 102 boxes fabricated from steel plate.
Repeated testing was a major feature of this project and, to achieve the required accuracy for the complex geometry, four compression-ring elements were bolted together in a trial assembly simulating the unstressed geometry. “The fastidious attention to detail and the meticulous testing thereof were a major part of this project’s success,” noted the judges.
Another stadium that received accolades at the Steel Awards ceremony was the winner of the specially added Sports Stadiums category, Soccer City, the flagship venue for the 2010 FIFA World Cup.
“It represents a true African aesthetic, combines outstanding steel, concrete and tensile materials that complement each other superbly,” said the judges of the stadium situated just outside Soweto.
The project involved the total refurbishment of the old FNB stadium into a 90 000 seater. The scope of works included 120 000 m³ of earthworks, 65 000 m³ of concrete, 7 500 t of reinforcing steel and 7 500 t of structural steel.
“This, in combination with the erection of 28 000-m² fibre-reinforced façade panels and 54 000 m² of polytetrafluoroethy- lene roof and ceiling membranes onto a complex three-dimensional double curvature steel structure, has resulted in this stadium being transformed into one of the most striking, impressive and well-equipped stadiums in the world,” said the judges.
Like the Moses Mabhida stadium, the roof of Soccer City is its most important and interesting element. The roof showcases the flexibility of steel through its curved shapes and radial arches, which form the central design element, dubbed ‘the calabash’.
“The calabash was a most appropriate choice for the shape of the showpiece of the 2010 FIFA World Cup. The integu- ment is defined by earthy African colours and an almost animal hide-like tightness, while inside, the stadium springs powerfully to life,” the judges commented.
“From a steel perspective, the deep overhanging roof and capacious circulation spaces are testament to the ability of steel to span large distances. If sports stadiums are the cathedrals of this age, then steel has contributed much to that sensation,” said the judges. “The sheer enormity of this project and its success as a symbol of Africa will boost the image of South African skill and expertise for generations to come.”
SAISC executive director Dr Hennie de Clercq said that the entries, a record number this year, reflected the outstand- ing quality of the local steel construction industry in all its diversity.
“We congratulate the winners but emphasise the exceptional quality of all the entries, which augur so well for the future of our industry,” he concluded.