Capital Gate is a skyscraper in Abu Dhabi adjacent to the Abu Dhabi National Exhibition Centre designed with a striking lean. At 160 m (520 ft) and 35 stories, it is one of the tallest buildings in the city and inclines 18° to the west. The owner and developer of Capital Gate is Abu Dhabi National Exhibitions Company. The tower (also known as the Leaning Tower of Abu Dhabi) is the focal point of the Capital Center/Abu Dhabi National Exhibition Centre master development.
Video Capital Gate
Construction
Foundation
The structure sits above an extensive distribution of 490 piles that have been drilled 100 feet underground to accommodate the gravitational, wind and seismic pressures caused by the lean of the building.Of the total 490 piles, 287 were 1 m (40 in) in diameter, and 20-30 meters (65-100 feet)deep, the remaining 193 piles had a diameter of 600 mm (24 in) with a depth of 20 m (65 feet). All 490 piles were capped together using a densely reinforced concrete mat footing of nearly 2 meters deep (7 feet).The piles which were initially in compression during construction to support the lower floors of the building, are now in tension as the stresses caused by the overhang have been applied.[1]
Core of the structure
Core of the capital gate is built using jumping form work. The center concrete core had to be specially designed to account for the immense forces created by the building's lean. The core, which contains 15,000 m of concrete reinforced with 10,000 tons of steel, uses vertical post-tensioning and was constructed with a vertical pre-camber. This pre-camber means that the core was constructed with a slight opposite lean, as each floor is installed, the weight of the floors and diagrid system pull the core and slowly straightening it out. it is constructed in the opposite direction.146 steel tendons are vertically placed in the concrete core each 20 mts long which is used for post tensioning.
Superstructure
The capital gate employs a fine grid that fits this 160 m tower, Diagrid made construction of this tower possible given its lean of 18 degree. There are two diagrid systems, an external diagrid defining the tower's shape and an internal diagrid linked to the central core by eight unique pin-jointed structural members. The external diagrid consists of 720 sections each of different shape as it is based on the direction in which it leans. The external grid carries the weight of the floor while the internal digrid connects with the external and transfers the load to the core[2] .There by creating no columns in the floor .
Maps Capital Gate
World records
In June 2010, Guinness World Records certified Capital Gate as the "World's furthest leaning man-made tower." The new record shows that the Capital Gate tower has been built to lean 18° westwards; more than four times that of the Leaning Tower of Suurhusen. Investigation and evaluation, which was made by a Guinness appointed awards committee, started in January 2010, when the exterior was completed.
The gravitational pressure caused by the 18° incline is countered by a technique called pre-cambered core, using a core of concrete reinforced with steel, with the core deliberately built slightly off-centre. It is also anchored to the ground by 490 piles which are drilled 20-30 metres underground.
Architecture and design
The building has a diagrid especially designed to absorb and channel the forces created by wind and seismic loading, as well as the gradient of Capital Gate. Capital Gate is thought to be the Middle East's first building to use a diagrid; others around the world include London's 30 St Mary Axe (Gherkin), New York's Hearst Tower and Beijing's National Stadium.
The Capital Gate project was able to achieve its inclination through an engineering technique, known as pre-cambering, that allows floor plates to be stacked vertically up to the 12th storey, and staggered, one over another by between 300 mm to 1400 mm.
Capital Gate was designed by architectural firm RMJM and was completed in 2011. Capital Gate now houses the 5-star Hyatt Capital Gate hotel and additional office space.
Project time line
- September 2007 - Enabling works commence
- November 2007 - Pile driving starts
- April 2008 - Core wall construction starts
- February 2009 - Façade commences
- May 2009 - Reaches 100 m in height
- June 2009 - Incline starts to take shape
- October 2009 - Attains final height of 160 m
- December 2009 - Completion of exterior core structure
- January 2010 - First phase of splash completed
- February 2010 - Interior fit-out commences
- March 2010 - Commencement of link bridge to Abu Dhabi National Exhibition Centre
- April 2010 - Commencement of atrium roof
- 2011 - Completed construction
- Opening date 21 Dec 2011
See also
- List of leaning towers
- List of tallest buildings in Abu Dhabi
- Diagrid
- List of twisted buildings
References
External links
- Capital Gate official Website
- Capital Gate - World's Furthest Leaning Man-made Tower
- Capital Gate Tower at CTBUH website
Source of the article : Wikipedia
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