The Burj Khalifa is a mixed-use skyscraper in Downtown Dubai and the tallest building in the world. It reaches 828 metres and has 163 inhabited floors, plus a spire, and it was designed by Adrian Smith while at Skidmore, Owings & Merrill. Construction began in 2004 and the tower opened on 4 January 2010.
Design
The plan is a three-lobed, or Y-shaped, footprint derived from the geometry of the desert flower Hymenocallis. The shape is not decorative: it reduces the wind forces on the tower, which is why the building can be as slender as it is tall. A buttressed core — three wings tied together by a central hexagonal core — carries the lateral loads, and the tower's setbacks spiral upward so that the building's width changes as it rises, further confusing wind vortices.
The cladding is a curtain wall of aluminium and glass panels with a reflective coating, specified for the extreme heat and sand of the Gulf. The total floor area is in the region of half a million square metres.
Use
The tower contains residential apartments, the Armani Hotel, corporate offices and the observation decks. At the Top, on level 124, and At the Top Sky, on level 148, are the public observatories, and the tower sits beside the Dubai Mall and the Dubai Fountain within the Downtown Dubai development.
Records and engineering
It has held the record for the world's tallest building since opening, taking the title from Taipei 101. The concrete used was pumped to record heights during construction, and the tower's elevators are among the fastest in the world. The total height was increased more than once during construction, which was possible because the Y-shaped plan and the buttressed core could be extended without redesigning the structure.
Visiting
The observation decks are ticketed, and the tower is entered from the Dubai Mall; the surrounding plaza, the fountain shows and the Burj Park are open to the public. The building is one of the most visited paid attractions in the country.