Burj Khalifa – Structural Engineering
Rising 828 meters over the desert metropolis of Dubai, the Burj Khalifa tower is the world's tallest structure. The 280,000-square-meter skyscraper contains office, residential, and retail space, along with a Giorgio Armani hotel. Built of reinforced concrete and clad in glass, the tower is composed of three elements arranged around a central buttressed core. As it rises from a flat base, setbacks occur at each element in an upward spiraling pattern, reducing the tower’s mass as it reaches skyward. At the pinnacle, the central core emerges and is sculpted to form a spire.
SOM created a simple Y-shaped plan to reduce wind forces, as well as to foster constructability. Each wing, with its own high-performance concrete core and perimeter columns, buttresses the others via a six-sided central core, or hexagonal hub. The result is a tower that is extremely stiff torsionally. SOM applied a rigorous geometry to the tower that aligned all of the common central core and column elements.
The setbacks are organized in conjunction with the tower’s grid: the stepping is achieved by aligning columns above with walls below to provide a smooth load path. This enabled construction to proceed without the normal delays associated with column transfers. At each setback, the building's width changes. The advantage of the tower's stepping and shaping is, in essence, to “confuse the wind.” Wind vortexes can never sufficiently coalesce because the wind encounters a different building shape at each tier.