Top practitioner (AKA @toothsairysa) takes your questions
Raising the Roof at Cape Town Stadium
Cape Town's 2010 World Cup stadium is taking shape rather nicely!
The slow and complex procedure of raising the inner ring of the Green Point stadium roof was completed in February 2009.
This marks another milestone on the route to the 2010 FIFA World Cup.
The process of tightening the “spokes” and raising the inner ring of the roof structure from ground level to a height of 34,5 metres began on Monday 9 February and was successfully completed on 18 February 2009.
Mike Marsden, Executive Director responsible for 2010 with the City of Cape Town, said that the inner Tension Ring had been successfully installed by using hydraulic jacks that progressively tightened the 72 cables connecting the inner and outer rings of the roof. A total of 7,4 km of cabling weighing 370 tons was raised.
The operation was closely monitored by the City's structural engineers who expressed their satisfaction. The next phase is the positioning of steel trusses, the installation of the 9000 pieces that make up the glass roof surface, and the attachment of a fabric membrane below the roof. The 4500-ton roof is scheduled for completion in September 2009.
Attached to the inner tension ring of the roof will be a "ring of fire" which includes the stadium floodlights and an extension that will light the stands. The pitch itself will not be covered.
Rainfall run-off from the roof will be collected in ponds and used for the irrigation of the golf course on the surrounding Green Point Common.
The 36 000 square metre hanging roof is curved to give the stadium a flowing look from every perspective. It will be translucent to take full advantage of natural light and will be weighted down with 3500 tons of steel and 1000 tons of glass, to cope with Cape Town’s strong winds.
Marsden said the roof had been designed to comply with stringent environmental requirements relating to acoustic dampening, aesthetics and the floodlighting.
The roof also complied with FIFA's technical requirements in terms of spectator coverage. “A major advantage of the design is that there are no cables or structural elements that could cast a shadow on the pitch during matches,” he said.
The next major stadium projects, says Marsden, are the construction of the outer façade, the seating, furniture and fittings and finally the laying of the grass pitch which is being carefully cultivated in Stellenbosch in compliance with FIFA requirements.
Marsden said the stadium was on track for completion on 14 December 2009.
Green Point Stadium Visitor Centre:
Address: Vlei Road, Greenpoint
Contact no: +27 (0)21 430 0410
Read more about out how to buy 2010 world cup tickets, and stay up-to-date with 2010 news by browsing our Sport & FIFA 2010 section and subscribing to our Editor’s Picks Newsletter.