Burj Dubai is the height of success

Dubai: The sky's the limit for building a tall tower today, says Greg Sang, projects director of Emaar Properties, who is overseeing the construction of Burj Dubai. Asked whether building a 1km tall tower is possible, he said: "There's no limit. Anything's possible. You can design anything. It's not a technical question, but an economical one."

At the bottom of a super-tall tower there will be massively thick walls, leaving room for nothing else and hence making the floors useless. The taller the tower, the thicker the walls. "Will that be economically feasible," he asked.Burj Dubai presently at 629 metres is an impressive structure close-up. But to get an idea of the scale of this tower you have to step back all the way to Jebel Ali or catch a glimpse of it driving on Al Khail Road. It is said that when the tower is completed, the top of the spire will visible 95 kilometres away. Highest observatory I was itching to get to the top but Sang nixed the idea citing safety reasons. Construction is going on at a hectic pace and once you book a hoist you have to keep to the schedule. From the Burj's sales centre nearby I could see elevators busily moving up and down in slow motion.

When the observatory is built at the top, it will be the world's highest deck accessible to the publicOne can be taken there by an elevator travelling at 10 metres per second. "This has broken all sorts of records. It is the tallest man-made structure built on the planet," said the project director, who has 7,000 workers on the site, besides a 300-strong management, supervision staff and contractors and engineers. "It is a huge achievement for Dubai."

The challenge for such tall structures is how to tackle the powerful winds at that height. Technology allows the building to sway while an internal damping devise absorbs the wind energy and stabilises the building.

Burj Dubai will sway 1.5 metres, that's about the height of an average person. Asked whether people on the top will get seasick, Sang gave an analogy"When a building sways, what people feel is not the amount of movement, they feel the acceleration and deceleration. As an example, if you are driving your car at a constant speed of 100km/h you don't feel any motion. But step on the brakes or the accelerator, that's when you feel it. The motion is below the acceptable limits," he said. Asked what it is about tall towers that fascinate people, Sang said it goes back thousands of years to the Tower of Babel.

"The height says something about the strength of the economy. He said in the 1900s when skyscrapers were first built in the United States, it wanted to show industrial might. Then in the 1980s to the 1990s, when Asian economies took off, there were structures like the Petronas Towers in Malaysia and Taipei 101 in Taiwan. "Now it is the Middle East where the growth rates are in double digits," he said.

Ron Klemencic, chairman of the Council of Tall Buildings and Urban Habitat, has remarked that once buildings get above 80 storeys or so they start to lose their economic viability. "Beyond 80 floors prestige is the driving factor," he said. But Sang said highrises make a lot of sense because they are efficient. When you have such a dense population in one place, per capita energy consumption is a fraction of that in villas in the suburbs, he said. And you don't have to hop into your gas-guzzling SUV to go shopping. The mixed-use Burj will have 35,000 people living and working in the tower