The new Green Point Stadium has reached another significant construction milestone, with work starting on lifting the cables of the stadium roof.
The 4 500 ton roof is a unique design feature of the city’s new multi-purpose stadium. It will hang inwards, and will be supported by an inner tension ring and an outer compression ring.
This is the first time such cutting-edge technology - which is imported mainly from the USA and Germany – is used in Africa.
Dave Hugo, the City’s 2010 Director: Technical, led a delegation into the stadium construction site on 10 February 2009 to demonstrate the 72 radial steel cables arranged symmetrically around the lower stands and pitch.
These cables, which are 85-98mm in diameter, will be slowly tightened by 72 hydraulic jacks on the columns supporting the outer compression ring. They will then slowly rise off the ground until they are in position, 34.5 metres above the pitch.
The process may be likened to the tightening of the spokes of a bicycle wheel.
“We have started the tensioning process,” Hugo said. “This is a great milestone for the stadium.”
The next phase of the complex roof construction process will involve the installation of steel trusses, then the placement of 16mm thick glass panels and a fabric membrane underneath.
The glass roof will cover the stands but not the pitch, and will not be visible from outside the stadium. It will also incorporate the pitch lighting around the inner tension ring to negate the need for unsightly floodlight stands. The roof design will also reduce noise pollution from the stadium during events.
These design features are in accordance with the environmental guidelines contained in the Provincial Government of the Western Cape’s Record of Decision on the environmental impact of the stadium on the surrounding area.
“It’s an iconic and special design,” said Hugo. “The architects have done a fantastic job with the design.”
Hugo also gave an update on the stadium’s progress. All the concrete work has been completed, and the areas where the temporary seating will be situated are clearly visible. After hosting eight 2010 FIFA World CupTM matches, the stadium will be reduced from 68 000 seats to 55 000 seats. The new operator – a consortium of Stade de France and the SAIL Group – will use this space for operational purposes.
Hugo said the grass for the pitch is being grown near Stellenbosch.
The facade of the stadium will be completed during September 2009, and the entire stadium is on track for completion on 14 December 2009, he added.