麻豆传媒

鈥淭HE engineering is the art, and the art is the engineering.鈥� So says Cecil Balmond, structural engineer, designer and artist, who together with Turner prize-winning sculptor Anish Kapoor has created an innovative tower that challenges conventions in engineering and design to commemorate the 2012 Olympic games in London.

Next month, the last piece of red, snaking steel will be placed atop London鈥檚 newest landmark: the ArcelorMittal Orbit in the Olympic Park in Stratford, London. At 115 metres high, the sculpture will be the UK鈥檚 tallest, towering over the Statue of Liberty. Built by engineers at international firm Arup, the tower is made from 2200 tonnes of steel provided by steel company ArcelorMittal, which is stumping up 拢19.6 million of the 拢22.3 million price tag.

Kapoor and Balmond鈥檚 design was a direct response to a call from London鈥檚 mayor Boris Johnson for an iconic tower for the games. We thought: what can we do that is different, recalls Balmond, who runs the Balmond Studio in London.

Most towers are the same: vertical, flaring out at the bottom and thinning at the top, says Balmond, who until recently headed up Arup鈥檚 Advanced Geometry Unit. 鈥淲hat could be different is an orbit,鈥� he says. The sculpture follows an orbit, linking with itself for stability. 鈥淟ike a planetary orbit it goes round and round and round and is stable. So instead of a straight continuous cone, we have an orbit,which each time it passes itself it connects.鈥�

鈥淭he sculpture follows an orbit, linking with itself for stability. A steel pendulum dampens any wobbles鈥�

To design the tower along these lines, Balmond and Kapoor took two foci in space and made the structure loop continuously round them in a figure of eight motion. They used a computer program to do this, specifying limits at the top and bottom. At the bottom limit, the looping is cut off, leaving the sculpture supported on an inherently stable tripod. 鈥淚t鈥檚 very, very stable even though it looks energetic and is not a traditional form,鈥� says Balmond.

Adding to this stability, the tower has a swinging steel pendulum, called a 鈥渢uned mass damper鈥�, which stops the top of the tower wobbling. 鈥淭he structure is stable but flexible like a tree,鈥� says Holger Falter, the lead engineer behind the tower at Arup.

Balmond adds that in most towers gravity acts vertically, but in the ArcelorMittal Orbit it acts through the points where the looping steel meets.

Other practical challenges had to be overcome. Falter says mathematics allowed them to calculate wind forces on the tower precisely, and that the tower鈥檚 spread-out base reduces these.

Balmond holds that the artistic and engineering aspects of the tower work together. 鈥淭here are no compromises on structure and art 鈥� they both make the same statement,鈥� he says.

The statement is the sculpture鈥檚 dynamism and energy, which the designers hope will give the visitor a 鈥渘arrative in space鈥�. Like much of Kapoor鈥檚 work, the ArcelorMittal Orbit plays with notions of light and dark, with visitors entering the tower through a sunken black crater to be taken up to the light upper observation decks in a lift.

Balmond knows that not everyone will applaud their creation. 鈥淚t鈥檚 primeval. It鈥檚 not polite. It鈥檚 strong. People will read things into it. Some will love it. Some will hate it.鈥� But he adds: 鈥淚 hope people will enjoy moving through its narrative.鈥�