2010

Burj Khalifa

Adrian Smith (b. 1944), Bill Baker (b. 1953)

The Burj Khalifa opened in Dubai in 2010, becoming the tallest building in the world by far—over half a mile (0.8 km) tall. There were a number of challenges in this project, faced by architect Adrian Smith at the firm Skidmore, Owings and Merrill (which also designed One World Trade Center in New York City), and structural engineer Bill Baker. An obvious one involves the stiffness of such a tall structure—how to keep it from swaying like a reed in the wind.

The foundation of any skyscraper is key, and with a building this tall it needs to be robust. So engineers created what is called a piled raft. They started by sinking nearly 200 steel piles 155 feet (47 meters) into the ground. They are 5 feet (1.5 meters) in diameter and filled with concrete. On top of the piles engineers designed a 12-foot-thick (3.7 meters) concrete raft. The building rises on top of this raft.

The core of the building is a hexagonal tube filled with elevators, stairs, and utilities. Around this tube are three buttresses that support the core and contain the actual floor space that tenants use. The buttresses taper until, at the top of the building, nothing but the central core remains.

Structurally, the entire building depends on concrete and steel. Each buttress is in essence a gigantic vertical I beam with 2-foot-thick (0.6 meter) steel-reinforced walls forming the flange and web of the beam. The steel is straightforward but the concrete required finesse. Construction using concrete is a challenge in such a hot climate. Engineers used ice in the mix and pumped concrete at night to prevent overheating and cracking.

The outer surface is a traditional curtain wall of glass, aluminum, and stainless steel. What is shocking is the amount of glass—it is said that the 26,000 panes of glass could cover 25 American football fields. The result is a building that is artistically stunning. It is an engineering marvel that is surprisingly beautiful.

SEE ALSO Great Pyramid (2550 AAA), Concrete (1400 AAA), Woolworth Building (1913), World Trade Center (1973).

Skyline view of downtown Dubai, UAE, showing the Burj Khalifa and Dubai Fountain in 2010.