Burj Dubai

As of tomorrow, there’s a new tallest building on the planet.  When Petronas Towers, and later Taipei 101, opened, there was a good bit of arguing over what constituted the “tallest building in the world,” since both of those were, arguably, shorter than the Sears Tower in Chicago–by a fair margin.  Once Burj is open, there won’t be any arguing.  Its exact height remains a closely guarded secret, but it’s at least 800 meters tall (2625 feet compared with Sears’ 1454), or just about half a mile.

The headlines, of course, are whether anyone is left in Dubai to move in, and the economics of the tower raise important questions about resources, functionality, and whether buildings this tall are really just exercises in ego.  The short answer is that no, no tower really needs to go that high, the economics of mega-projects like this have proven toxic in almost every case, and the functionality of elevators in particular means that towers this tall don’t work in ways we’ve come to expect.  While apartments near the top sold for almost $1900 a square foot in the midst of Dubai’s boom, buyers today are being courted with prices half that amount, and whether anyone has the cash or the desire to stay in the ‘seven-star’ Armani hotel is a question that seems likely to answer itself.

But, the client in this case was the one who, for whatever reason, pushed SOM to explore the limit of what was possible, and there’s no question that the engineering feat here is pretty remarkable.  Burj Dubai has redefined what happens at super-tall heights, as the design team discovered that their primary structural mission, after making the thing stand up, would be shedding turbulent wind vortices that might otherwise have set up disastrous vibrations.  So, while the publicity will talk about the ‘floral’ shape of the tower’s plan, the engineers will sit back and chuckle, knowing that the lobes, asymmetries, and cladding fins are all about making sure the thing doesn’t shake itself to pieces.

As for Sears?  It can comfort itself knowing that it’s still the world’s tallest commercial office tower.  And it seems likely to hold that title, as the shapes of the new generation of supertalls almost require small-floorplate apartments near the top to be lettable.