"Structural Design of the World s Tallest Building: The Burj Dubai Tower"
By: William F. Baker, SOM Partner in Charge of Structural and Civil Engineering, Chicago; D. Stanton Korista, SOM Director of Structural Engineering, Chicago; Lawrence C. Novak, SOM Associate Partner, Chicago.
The Burj Dubai Tower, when completed, will be the world’s tallest structure. The superstructure is currently under construction and as of the start of 2007 has reached near 100 stories. The final height of the building is a “well-guarded secret.” The height of the multi-use skyscraper will “comfortably” exceed the current record holder of 509 meter-tall (1,671 feet) Taipei 101. The 280,000m2 reinforced concrete multi-use Tower is utilized for Retail, a Giorgio Armani Hotel, Residential, and Office. The goal of the Burj Dubai Tower is not simply to be the world’s highest building; it’s to embody the world’s highest aspirations.
Designers purposely shaped the structural concrete Burj Dubai—Y-shape in plan—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 a “buttressed” core. 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 the common central core and column elements to form a building.
Each tier of the building steps back in a spiral stepping pattern up the building. 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. This allows the construction to proceed without the normal delays associated with column transfers.
The setbacks are organized such that the Tower’s width to change at each setback. The advantage of the stepping and shaping is to “confuse the wind.” The wind vortexes never get organized because at each new tier the wind encounters a different building shape.