Orange County Branch Newsletter

February 2010

Secretary's Column

The Tallest Building in the World

By Tapas Dutta, PE

On January 4, 2010, the tallest building in the world, the Burj Khalifa (formerly known as the Burj Dubai) was formally opened in Dubai, United Arab Emirates (UAE).  At 2,717 feet (828 m) it is the tallest man made structure ever constructed. Construction began on September 21, 2004 with the exterior of the structure completed on October 1, 2009. The building is part of a 490-acre developmemt called the Downtown Burj Khalifa. The total cost of the building was aboit $1.5B and for the entire Downtown development about $20B.  The Downtown, a 7.4 acre development will consist of at least 19 towers, the Dubai Mall and a man-made lake. The building consists of 160 habiltable -floors, 46 maintenance levels and two parking levels in the basement. The total floor area is about 3,595,100 square feet. The building was named in honor of the current President of the UAE and ruler of Abu Dhabi, Sheikh Khalifa bin Zayed al Nahyan.

The primary architecture and engineering consultant was Skidmore, Owings and Merrill (SOM) of Chicago, who was also responsible for the Sears Tower in Chicago (now renamed as Willis Tower).  Adrain Smith was the chief architect and Bill Baker was the chief structural engineer.  The primary contractor was Samsung C&T of South Korea who also built the Petronas Towers in Kualalumpur, Malaysia and the Taipei 101 buildings.  Major sub-contractors included the Belgian group Besix and Arabtec from the UAE. Turner Construction Company was the construction manager.  Under UAE law, the Contractor and the Engineer of Record are jointly liable for the performance of the building; Hyder Consulting was legally the Design Consultant for the project.

Originally, the project was to be a virtual clone of the 1,837-feet Grolla Tower proposal in Melbourne, Australia; the tower went through several redesigns.  The final height of the tower was a closely guarded secret until the very end.

The building resembles the bundled tube structure of the Sears Tower; however it is not a tube structure.  The design of Burj Khalifa is derived from patterning systems embodied in Islamic architecture. The triple-lobed footprint of the building was inspired by the flower Hymenocallis. The tower is composed of three elements arranged around a central core. As the tower rises from the desert below, setbacks occur at each element in an upward spiralling pattern, decreasing the cross section of the building at it rises. There are 27 terraces in the building. At the top, the central core emerges aned is sculpted to form a finishing spire. A Y-shaped floor plan maximizes views of the Persian Gulf.  During the design process, engineers rotated the building 120 degrees from its original layout to reduce wind stress. At its tallest point, the tower sway is about 4.9 feet.  Over 40 wind tunnel tests were conducted to evaluate wind effects.

The building weighs over  550,000 tons. The spire, which also houses communication equipment,  is composed of over 4,400 tons of structural steel. The central pinnacle pipe weighs 390 tons and was constructed from inside the building and jacked to its full height of over 660 feet using a strand jack system.

The primary structural system is reinforced concrete (58,900 cubic yard weighing 120,000 tons). The foundation consists of 192 piles, each pile being 5 feet in diameter and 141 feet long. A high density low permeability concrete was used in the foundation. A cathodic protection system under the mat was used to minimize any detrimental effects from corrosive chemicals in the local ground water.

The exterior cladding of the building consists of 1,528,000 square feet of reflective glazing, aluminium and textured stainless steel panels with vertical tubular fins designed to withstand Dubai’s extreme summer temperatures.

The building will have mixed occupancy including an Armani Hotel (first of its kind), corporate suites, residential suites , restaurants and public observation decks. The building is expected to hold 25,000 people at any given time. A total of 57 elevators and 8 escalators comprise the vertical transport system., the fastest traveling at 33 feet per second.  The building has 2,909 stairs from the ground floor to the 160th floor.

To wash the 24,348 windows, a horizontal track has been installed on the exterior.

Outside the building there is the Dubai Fountain illuminated by 6,600 lights and 50 colored projectors. The fountain is 900 feet long and shoots water 490 feet into the air accompanied by music. It was designed by WET Design who was also responsible for the fountains at the Bellagio Hotel in Las Vegas.

The Burj Khalifa is surrounded  by an 1.2M square feet park. The park has six water features, walkways and flowering trees. The plants and the shrubbery will be watered by the building’s condensation collection system which will provide about  15M gallons annually.

The opening ceremony featured a display of 10,000 fireworks, light beams projected on and around the tower and other sound, light and water effects.

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