Burj Khalifa , Dubai - The World's Tallest Building

The World's Tallest Building, Burj Khalifa officially opened Jan. 4 in Dubai, the United Arab Emirates.The height of Burj Khalifa is 828 meters, or 2,716.5 feet. The building was designed by Chicago Architect ADRIAN SMITH."It was the culmination of many years of work and one of the most thrilling moments of my career," said Smith, who left SOM in 2006 to start his own firm, Adrian Smith + Gordon Gill Architecture.

"The Burj Dubai, now Burj Khalifa, was designed not for ego gratification or to fulfill a list of superlatives. It was designed to lift the spirits of a nation and a culture, and to bring joy and inspiration to its citizens."

The design of Burj Khalifa was commissioned by its developer, Emaar Properties, after SOM won a design competition in early 2003. Smith's design of the form of the building is geometric in plan, starting with three branches and three pods. Setbacks occur at each program element, decreasing the tower's mass as it rises toward the sky. At the tower's top, the central core emerges and is sculpted to form a finishing spire. Views of the Arabian Gulf and city are maximized throughout the building through the use of a Y-shaped floor plan inspired in part by certain early designs of Mies van der Rohe as well as Chicago's Lake Point Tower.

Emaar was interested in having Burj Dubai be the tallest building in the world, but that standard could have been met with a building much shorter than the one Smith and his team ended up designing. But Smith envisioned Burj as a very elegant, slender building, and to resolve the design in an appropriately proportional way required a great deal of height-quite a bit more than Emaar had originally expected. In the end, the height of the project was changed from 700 meters (2,296 feet) to "something taller" when Smith changed the massing at the tower's top. (The world's next-tallest building is Taiwan's Taipei 101 at 1,670 feet.) Burj Dubai's official height was announced last week at 828 meters, or 2,716.5 feet.

Burj Khalifa will continue to be the world's tallest building for at least five years, since no announced projects of greater height have actually broken ground yet, and it will take at least five years of construction for another tower to exceed the height of the Burj.

Burj Khalifa includes luxury condominiums, the world's first Armani hotel with ballroom and support amenities, meeting facilities, 50,000 sm of luxury office space, restaurants, health club, spa, outdoor swimming pool, tennis courts, the world's highest public observatory, three floors for communications equipment, 6 mechanical floors and 3,000 parking spaces. The tower's gross area is over 300,000 sm above grade, a total of 450,000 sm including below-grade levels.

Smith's design focuses on several unique problems posed by supertall buildings. Coordination of the results of wind tunnel testing and concerns with stack effect led to the development of special elements and mitigation strategies within the building and at the many building terraces. Window washing and the need to maintain the building's exterior wall led to the design of a system that incorporates over a dozen specialized mechanized units at several levels of the tower. Other innovative use of materials and systems include high-efficiency lighting; reduction in urban heat island effect with large water features and extensive landscaping above the garage podium roofs; and use of a site-wide gray-water system for irrigation including recovered condensate.

Wind tunnel tests were conducted to ensure the tower would perform optimally in response to weather conditions. In response to the tests, Smith and his design team sculpted the tower's shape, in particular by staggering the setback heights, to shed the negative forces of the wind moving around the building, which he calls "confusing the wind." He and the team also took several steps to mitigate the stack effect, which in Burj means that, due to the height of the building and difference between the internal and external temperature, indoor air tries to travel downward and flow out of the bottom of the building.

Skyscrapers such as Burj Khalifa are inherently sustainable because they accommodate a large number of people on a small footprint, which helps save agricultural land from development and reduce carbon emission associated with commuting to and from suburbs. They also offer efficient vertical and horizontal transportation systems, encouraging the use of public transit and creating increasingly walkable cities. Supertall buildings can also be formed to further decrease their environmental effect and become "super-sustainable." These structures can take advantage of the faster wind speeds at higher altitudes and drive wind toward building-integrated turbines to generate power. Because they are less likely to have shadows cast on them, high-rises also make efficient use of building-integrated photovoltaic systems to absorb solar power and generate energy. And deep foundations make them ideal for geothermal heating and radiant cooling systems.

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