8 jul 11  | The Wall Street Journal

Architect Q&A: The State of Super-Tall Towers

by Maura Webber Sadovi

Adrian Smith, 66, is the senior design partner at Chicago-based Adrian Smith+Gordon Gill Architecture. While at his previous firm Skidmore, Owings & Merrill, Mr. Smith designed the Burj Khalifa in Dubai, which at 2,717-feet high is the world’s tallest, along with China’s Nanjing’s Zifeng Tower, Chicago’s Trump International Hotel & Tower and Shanghai’s Jin Mao Tower.

He was recently awarded the 2011 Lynn S. Beedle Lifetime Achievement Award from the Council on Tall Buildings and Urban Habitat for his contributions to the field of super-tall buildings. (Some questions and answers below have been condensed.)

Q: What is the biggest challenge to designing tall buildings?

A: It’s a combination of making an elegant structure and one that also works with the major constraints such as wind. One of the major issues of tall buildings is how much they move from one side to the other and how rapidly they move. We try to minimize the movement through a number of ways that are both structural and architectural. The Burj Khalifa is as much an engineering strategy as an architectural strategy. The stepped shape helps to confuse the wind. The wind doesn’t have an opportunity to organize very rapidly because of the steps.

Q: How have the Sept. 11, 2001 terrorist attacks affected tall buildings?

A. It hasn’t really affected the desire for people to go tall but it made us more aware of building in redundancies and making the building more terror-proof. Sometimes stairs are wider or there are more stairs than there used to be and there’s more security around the buildings.

Q: Was there ever a time when you thought no more super-tall buildings would be built?

A: No, I never thought that. I think human nature is always going to go after spectacular achievements. As long as they can, they will.

Q: Will demand for the tallest buildings ever return to the United States?

A: There’s a strategy for developing super-tall buildings because in and of themselves they very rarely make money. So what they’re doing in China and in other locations like Dubai is they will use the tall buildings as a catalyst for developing the land around it and the person who owns the tall buildings and the land around it will make his money off the adjacent land. The tower itself gives the land around it the prestige, a location and an identity. One of the problems with doing that in the United State is that most of the time super-tall buildings are needed in the inner city. And you just can’t get that much land in the U.S. because we’re not really developing new cities.

Q: How high can we go?

A: The limiting factor is probably the elevator system. When you get higher than about 550 meters [about 1,804 feet] with a single elevator, the weight of the cable gets too heavy. And if you stack up two to three elevators now you’re spending time transferring from one elevator to another and my guess is people don’t want to do that. But if we can solve the elevator problem I know we can design to a mile high. I’ve designed an experimental building that would go a mile high….It’s a very, very large building of about six to eight million square feet.