As it rapidly approaches completion, the distinctive Capital Gate tower in Abu Dhabi is a great example of the Habtoor Leighton Group’s (HLG’s) engineering know-how and its results-driven project team.
Having graced the skyline for only a short period of time, the Capital Gate tower has already become a firm fixture on the Abu Dhabi landscape.
Featuring commercial office space as well as the 5-star ‘Hyatt Capital Gate’, the tower’s unique 18 degree lean has earned it a place in the Guinness Book of World Records as the ‘World’s furthest leaning man-made tower.’ This lean – more than four times that of the world famous Leaning Tower of Pisa – proved to be an engineering challenge for the project team.
Project Director, Craig Fyall, said the lean on the 160 metre-tall tower has 490 piles, drilled 30 metres underground to help resist the gravitational pull of the wind and the seismic forces caused by the lean itself. The project also has a number of other unique design features that necessitated expert engineering skills.
Capital Gate’s floor plates are stacked vertically to the 12th storey, after which they are staggered over each other by between 300mm to 1,400mm, giving rise to the tower’s dramatic lean.
The tower features other innovative construction techniques, such as the world’s first known use of a pre-cambered, post-tensioned core, which contains more than 15,000 cubic metres of concrete, reinforced with 10,000 tons of steel.
The core, deliberately built slightly off centre, has straightened as the building has risen, compressing the concrete and giving the building strength, and has moved back into a vertical position as the weight of the higher floors was added. The building’s design also provided a few additional peculiarities for the design team.
“Each individual section of the structure, glazing frame and glass was a specific size for a particular location,” Mr Fyall said. Combined with the fact that each floor was a specific individual size and shape we had a very unique engineering and logistical challenge on our hands.”
The project was awarded to the Habtoor Leighton Group by the Abu Dhabi National Exhibitions Company (ADNEC) in July 2007 and is currently nearing completion.
Featuring 35 floors of varying sizes, the tower consists of a basement level, a ground floor, a mezzanine level, 16 levels of office suites and 16 levels of five-star hotel accommodation, covering a total built-up area of 50,000 square metres.
The structure has 722 steel diagrids, with the smallest weighing five tonnes, and the largest close to 16 tonnes. The total weight of the steel structure is estimated to be 13,000 tonnes. With 65 skilled staff on the job and more than 1,700 labourers on site at the project’s peak, Mr Fyall said it required a significant focus on team work.
“One of our biggest challenges was working to a tight schedule with many changes, while maintaining the quality that a five-star hotel and a superior grade building demands,” he said. “We needed a strong proactive ‘can-do’ team to achieve our targets. From day one I worked hard at building a great results-driven team around me. The site introduced a set of team values and we all stuck to these to deliver a quality project that meets the client’s high expectations. It has been an intense project but one that I am very proud to have been involved in.”