THREE years ago this month the first fleet of construction equipment arrived on site alongside Abu Dhabi’s landmark exhibition centre to begin the enabling works for what has now received worldwide recognition at the World’s Furthest Leaning Manmade Tower – a distinction conferred by Guinness World Records to the Capital Gate last June.

Capital Gate, owned and developed by Adnec (Abu Dhabi National Exhibitions Company), has been built to lean 18 degrees westwards – more than four times that of the world-famous Leaning Tower of Pisa – and earned the Guinness recognition after rigorous evaluation by the Awards Committee since January this year, when the exterior of the 160-m-high, 35-storey tower was completed.

Commenting on the tower’s record-breaking achievement, Adnec chairman Sheikh Sultan bin Tahnoon Al Nahyan said: “Capital Gate is a landmark development for Abu Dhabi and with this recognition, the tower takes its place among the world’s great buildings. It is a signature building that speaks of the foresight of the emirate.”
Great cities need great buildings, says Capital Gate’s website. With this recognition, Capital Gate has certainly achieved the iconic status it has aspired for.
The tower’s distinctive futuristic design, aesthetic splendour and technical excellence makes it a modern marvel and a celebration of human achievement that reflects the dynamism of Abu Dhabi.
Additionally, Capital Gate provides a historic link to the past by integrating with the grandstand at the Abu Dhabi National Exhibition Centre, one of the world’s most modern exhibition venues and one used by the Sheikh Zayed bin Sultan Al Nahyan, the late President of the UAE and the Father of the Nation. The tower is linked to this historic grandstand through an innovative canopy – the ‘splash’ – commencing from level 18 of the tower and sweeping across the grandstand, creating a wave-like effect.
In terms of design, nothing is standard about Capital Gate, which was designed to provide no symmetry so it inspires those within and outside the tower.
Capital Gate forms the focal point of Capital Centre, the world’s first exhibitions lifestyle destination, comprising 23 towers including branded hotels, commercial buildings, residential and serviced apartment complexes and developments for mixed use, located in close proximity to Adnec.

Designed by international architecture firm RMJM and with a total built-up area of 53,100 sq m, the tower contains 35 storeys with floors 2 to 16 comprising 20,900 sq m of premium office space. When fully complete by the end of this year, floors 18 onwards will house the 189-room, exclusive five-star Hyatt Capital Gate hotel, which spreads over 25,050 sq m. Floors 1 and 17 comprise plant rooms.
The tower has several other elements that enhance its reputation as one of the world’s most distinctive projects. Each room is different as is each pane of facade glass and every interior angle. Capital Gate’s shell comprises a super-strong exo-skeleton – a diagrid that carries all the weight of the floors while also providing an unobstructed floor plate precluding the need for pillars or internal beams and using much less steel than a conventional structural frame.

Capital Gate’s double-glazed facade achieves greater energy efficiency with waste air being pre-cooled between the inner and outer facades, before being expelled.
The glass used on the tower’s facade is a low emissivity glass used for the first time in the UAE. It is designed to keep the inside of the building cool and eliminate glare, while maintaining the transparency of the facade – an important design consideration.
The distinctive stainless steel ‘splash’ is a design element and a shading device that cuts out more than 30 per cent of the sun’s heat before it reaches the building thereby saving on the cooling load requirements within the building. The splash also twists around the building towards the south to shield the tower as much as possible from direct sunlight.

Capital Gate’s 19th storey outdoor swimming pool has an unrivalled panoramic view overlooking the Sheikh Zayed mosque, the Arabian Gulf, the Mangroves, Downtown Abu Dhabi and Saadiyat and Yas Island. A cantilevered tea lounge overhangs the tower’s exterior, 80 m above the ground. The tower also has a separate structural steel internal diagrid that has been used to create a tapered, 60-m-high atrium (from floor 19 to the roof).

Structure
This unique building is among the most technically challenging engineering projects in the world, given its gravity-defying 18-degree lean, the continuous twist of its form which ensures that the tower looks different from every angle and the unique nature of the floor plates.
Due to its unique shape, Capital Gate is being constructed on top of a concrete raft with a dense mesh of reinforced steel. The steel diagrid sits above an extensive distribution of 490 piles that have been drilled up to 30 m underground to accommodate the gravitational and wind loads. The angles and dimensions of the building facade have been meticulously designed to ensure that each individually-shaped panel accurately defines the shape of this magnificent structure.
Capital Gate’s floor plates are stacked vertically up to the 12th storey, after which they are staggered over each other by between 300 mm to 1,400 mm. giving rise to the tower’s dramatic lean.

The tower features other innovative construction techniques include the world’s first known use of a ‘pre-cambered’ core, which contains more than 15,000 cu m of concrete reinforced with 10,000 tonnes of steel. The core, deliberately built slightly off centre, has straightened as the building has risen, compressing the concrete and giving it strength, and moving into (vertical) position as the weight of the floors has been added.
Glazing work on the structure was completed early this year. More than 12,500 individually-shaped glass panels have been installed on Capital Gate’s facade in a complex engineering feat, which has taken Adnec and its construction partners 10 months to complete. In an intricate operation, each pane of glass had to be a slightly different shape and fitted at a different angle due to the building’s unique lean and its curved profile.
The glass panes on Capital Gate make up more than 700 larger glass “diamonds,” and were manufactured in the US with the steel frames holding the glass precision-cut in Austria before being shipped to the UAE.
Adnec stored the glass panels away from the construction site and delivered them as needed, on enormous flatbed trucks. Once they reached the construction site, they were meticulously placed into the correct position by on-site engineers.
The glass used is a highly energy-efficient, low ‘e’ category glass (Cardinal 240) containing two layers of silver inner coating allowing a high degree of natural light to permeate the building, while shielding users from harmful glare.

“The use of this advanced variety of glass is a ‘first’ for the UAE. The ‘pressure-plate’ system that has been developed for the steel frame, which holds each pane in place, guarantees the watertightness of the facade and allows thinner panes of glass to be used, thereby reducing the weight of the glazing system,” said Tony Archibold, associate director of RMJM.
The lean and curve of the building added considerable complexity to the glazing process, allowing little margin for error.
“Capital Gate has been a true design-and-build project from the very start. There have been numerous challenges, which I am pleased to say we have surmounted, thanks to a structured partnering programme and the hard work and commitment of everyone involved. Both Adnec and our partners have thoroughly enjoyed the opportunity to create an iconic structure, which is not only distinctive in appearance but also extremely functional,” said Ali Saeed bin Harmal Al Dhaheri, Adnec’s managing director.
Capital Gate’s status as one of the world’s most complex engineering projects has been further endorsed by a recent exclusive National Geographic television documentary. The ‘Megastructures’ programme devoted to the project – ‘The Leaning Tower of Abu Dhabi’ – has been translated into 44 languages and will be broadcast in 166 countries reaching a potential audience of 200 million viewers.

Link for the Statistics:

Lini for the Timeline: