Burj Khalifa, Dubai, United Arab Emirates

Tall, elegant, skinny. Sure it wasn't inspired by Naomi Campbell?Height: 828 meters

Cost to build: US$1.5 billion

Completion date: January 2009

Fast fact: Not only is this the world’s tallest building, it is also home of the world’s highest mosque, on the 158th floor. The tower is more than twice the height of the Empire State Building in New York.
Size isn't everything -- that's what the little guys always say.

Standing 828 meters high and weighing half a million tons, Burj Khalifa towers above its city like a giant redwood in a field of daisies.

It has been been the world's tallest building since 2010. 

Gigantic doesn’t begin to describe it.

This “desert flower” stands out comfortably among other skyscrapers and has become the symbol of Dubai’s bling, which often goes hand-in-hand with figures of per capita carbon footprints –- which Dubai also tops.

Overall structure

In addition to its aesthetic and functional advantages, the spiraling “Y” shaped plan was utilized to shape the structural core of Burj Khalifa.  This design helps to reduce the wind forces on the tower, as well as to keep the structure simple and foster constructability. The structural system can be described as a “buttressed core”, and consists of high performance concrete wall construction. Each of the wings buttress the others via a six-sided central core, or hexagonal hub. This central core provides the torsional resistance of the structure, similar to a closed pipe or axle. Corridor walls extend from the central core to near the end of each wing, terminating in thickened hammer head walls. These corridor walls and hammerhead walls behave similar to the webs and flanges of a beam to resist the wind shears and moments. Perimeter columns and flat plate floor construction complete the system. At mechanical floors, outrigger walls are provided to link the perimeter columns to the interior wall system, allowing the perimeter columns to participate in the lateral load resistance of the structure; hence, all of the vertical concrete is utilized to support both gravity and lateral loads. The result is a tower that is extremely stiff laterally and torsionally. It is also a very efficient structure in that the gravity load resisting system has been utilized so as to maximize its use in resisting lateral loads.

As the building spirals in height, the wings set back to provide many different floor plates. The setbacks are organized with the tower’s grid, such that the building stepping is accomplished by aligning columns above with walls below to provide a smooth load path. As such, the tower does not contain any structural transfers. These setbacks also have the advantage of providing a different width to the tower for each differing floor plate. This stepping and shaping of the tower has the effect of “confusing the wind”: wind vortices never get organized over the height of the building because at each new tier the wind encounters a different building shape.