Unlike The Leaning Tower of Pisa, one of the Seven Wonders of the World tilting 5.5° to the south, the 18° inclination of the Hyatt Capital Gate — opening early next year — was no accident. The Big Project looks at the technologies and challenges behind Abu Dhabi’s very-own wonder
When The Leaning Tower of Pisa first began to tilt, the town considered it an embarrassment. Yet for Abu Dhabi’s Hyatt Capital Gate, an 18° incline is its most-prized feature.
Made possible by a combination of post tensioning and the first-known use of a pre-cambered core, the 35-storey building used more than 15,000m3 of concrete, reinforced with 10,000 tons of steel and took more than three years to complete.
Opening early 2011 and standing at 160m, it is the cornerstone development of the Abu Dhabi National Exhibition Centre’s (ADNEC) Capital Centre; a 23-tower, US $2.2 billion mixed-use “micro-city”.
Pioneered by global architect RMJM, with owner and developer Abu Dhabi National Exhibitions Company, the design posed a number of challenges; from the structural support to interior design.
Calling it “awe inspiring and iconic”, Capital Gate sales director Adrian Hearn says: “Many aspects related to this iconic tower present design challenges, given there are no rectangular interior floor spaces. Various applications and finishes to all surfaces follow curved lines, the outside plan shape of walls and ceilings, the elevation walls of lift shafts and the vertical curving of the skin grid.
“In addition, every single floor plate has a slightly different shape from the level below or above. In summary, straight horizontal and angled line patterns working to ever-changing plan perimeter curves from floor to floor.”
To create the curve, floor plates are stacked vertically up to the 12th storey, then staggered until the 29th by 800 to 1400mm in relation to the shell. From the 29th to the 35th floors they range between 900 and 300mm in line with the facade. The overturning moment this creates is countered by a large podium footprint.
The facade was constructed using 700 diamond-shaped glass panels which form a dual diagrid system; Hyatt Capital Gate is the first building in Abu Dhabi to use this technology.
Created with 8500 structural steel beams, the heaviest individual diagrid weighs 16.5 tons but uses less steel than conventional frames, reducing costs and benefiting the environment.
It is the same technology used for London’s “Gherkin” and the Hearst Tower in New York.
“Globally, diagrid structures have been emerging as a new design trend for tall buildings with their powerful structural rationale and aesthetic potential,” says Gordon Affleck, design principal for RMJM Middle East.
“The incredible technical achievement and aesthetic splendour of Hyatt Capital Gate ensures it will be regarded around the world as one of the most magnificent buildings ever constructed,” he adds.
To protect against gravitational, wind and seismic pressures, the foundations of the building are formed from 490 piles, dug up to 30m underground and reinforced with 7000m3 of concrete. Above the foundations is a 2m-deep concrete base, filled with a dense mesh of reinforced steel.
Designed to mimic a wave, the building also features a ‘splash’; a completely independent steel canopy that has been fixed to the main building with I-beams.
And with its 18° westward incline, the Hyatt Capital Gate holds the world record for the world’s furthest-leaning manmade tower.
The building will comprise offices and a hotel, offering city and coastline views, while providing a “sense of flotation” through the interior design and a pool which appears to be suspended in mid-air from above.
“The convex curve of the structure seems to make the building disappear on the north west elevation. Equally on the opposite side of the building, facing south east, there will be even more dramatic bedroom views and a gravity play with flotation where the 19th floor cantilevered swimming pool seems to be suspended mid-air,” says Affleck.
It’s not the first European landmark Abu Dhabi has emulated, with the development of a Guggenheim and the Abu Dhabi Louvre planned for Saadiyat Island.
Yet the objective for Hyatt Capital Gate is not to emulate existing landmarks, but rather to create developments that look towards the future.
“Capital Gate is a landmark development for Abu Dhabi. It is a signature building which speaks to the foresight of the emirate,” concludes ADNEC chairman HE Sheikh Sultan bin Tahnoon Al Nahyan.