Published on Feb 14, 2016
A perfect circle at the water’s edge, ‘Aldar’s new head quarter’s is the centre piece of Al Raha Beach’ an exclusive new city on the out skirts of Abu Dhabi. Refreshingly modern it’s geometric shape symbolizes unity, stability and rationality. The elegance of this 23 – storey building belies it’s complex steel structure and super fast construction schedule. To meet the tight dead line, the project team worked closely together, using advanced 3D models developed by Arup.
The striking shape of Aldar’s headquarters is achieved through the use of a structural diagrid a diagonal grid of steel. The first of it’s kind in the United Arab Emirates, it largely eliminates the need for internal columns to support the building.
EVOLUTION OF A REVOLUTIONARY DESIGN
Sheikh Khalifa, the ruler of Abu Dhabi which is the richest city on earth wanted to transform the skyline and compete with the international elite of London, New York and Hong kong. Today, Abu Dhabi is a thriving metropolis, Sitting atop the world’s fifth largest oil reserve but black gold alone could not put this city in the super league. To do that, Sheikh khalifa had to lure big business and tourist dollars Abu Dhabi required to expand to thrive.
To put Abu Dhabi on the world, map, fledging property developers. Aldar planned a whole new micro city Al Raha Beach. It’s an ambitions proposal. At 11 kilometers long and almost a kilometer wide, this city on the sea will be the biggest project ever attempted in Abu Dhabi’s history. The vision of his highness and Aldar was to create this almost mini city where people can live, study, play and work in one destination. Al Mubarak, Chief Commercial officer of Aldar properties was in charge of delivering this audacious development.
Al Mubarak knew that he must attract investors if Al Raha Beach was to succeed. So, to launch the project, he commissioned a signature sky scraper. Creating an iconic structure on Al Raha Beach was of Vast importance for putting the Al Raha Beach on the world map. Al Mubarak set Lebanese architect Marwanzgheib the task of designing the icon. He raised the stakes even higher by deciding that the skyscraper will become Aldar’s head quarter’s in the heart of their Colossal development.
Creating some thing new in a land where building some thing iconic had become an everyday job was not easy. Neighbouring emirate Dubai had taken centre stage with a number of head line hitting projects. The world’s tallest skyscraper Burj Dubai. The palm, the emblematic Burj Al Arab were stealing the show. To stand out from the crowd, Zgheib knew that he must redefine the extra ordinary. Zgheib design was simple but daring. A round skyscraper taller than the statue of Liberty, with a curved glass skin covering the area of four football fields. The moment Zgheib imagined it, he knew it was a winning concept it was really something different, an unusual concept.
Zgheib’s design was inspired by nature. Two giant circular curved walls of glass mirror an open clam shell. It’s like a seas shell. The sea shell has deep meaning for Abu Dhabi with it’s sea faring heritage
CHALLENGES MET IN THE MAKING OF ALDAR
The first thing Zgheib had to do was to find out if his design could actually be built. He knew from the first moment that the engineering of that building was not going to be simple. The circular design in itself was a problem. Just like a coin that stands on its edge, it risks being unstable. The circle must be balanced, so, Zgheib turned to some very old school of geometry. The real challenge was to find the two points where the building should pose on the ground and for that zgheib had to go back to one of the oldest rule in architecture proportion.
When you have a circle you can divide it in to a pentagram and that pentagram defines the two points of the circle where the façade will lay on the ground and this helped in creating the perfect balance. It was the same thinking that led 16th century philosopher Heinrich Agrippa to draw man as a pentagram inside a circle and has helped architects to proportion buildings for centuries.
BUILDING A SOLID GROUND IN SEA WATERS
It was not the skyscraper itself that posed the first major challenge. It was the proposed site. Unbelievably, the solid ground required for Aldar HQ did not exist.
The desired location was 700 metres out in the Persian gulf and eight metres under water. Newland had to be created over 3 million cubic metres of sand had to be found which seemed to be a simple task with Abu Dhabi’s endless desert dunes, but desert sand is too fine to build with. The land would just slide into the Sea. Marine sand was needed. It’s larger grains help it stick together, creating the perfect base to build on.
Dredging sand from the seabed was one solution but fortunately, the last sheikh already done the job for the engineer’s. Whilst cutting a shipping channel in the late 1970s, Sheikh Zayed created an island of discarded sand. Luckily, it was just across the water so the engineers decided to move all 20 million cubic metres of it. A fleet of cutter dredgers at their way into the is l and. These were no ordinary dredgers. It takes an enormous claw layered with 48 reinforced steel teeth to slice through the hardned sand. The sand was pumped through a floating pipe to the construction site. Here, excavators toiled 24 hours a day to flatten the virgin ground. After 8 months, the land for Aldar HQ was fully formed, and with this, the first major problem was Overcome.
Aldar wanted their skyscraper completed by an astonishing deadline.In just 30 months time because by then Abu Dhabi was to host it’s first formula One grand prix. The race track was on it’s own designated island complete with hotels and theme parks and Aldar. The international press and tens of thousands of visitors were descending on the city. It was the ideal opportunity for Aldar to showcase their new Head quarters.
When the engineers mapped out the programme, it was realised that basically from this blank sheet of paper they would have to start piling within two months which was absolutely unprecedented for a building with a new and unique geometry. To stand any chance of meeting this target, the team had to pull out all the stops.
With the clock ticking, the ground was prepared for the foundations to carry the loads of Aladar Head quarters into the ground. Normally ,blue prints are complete before construction begins, but Aldar HQ’s deadline made this impossible. Given the programme challenges with this project only way for the team to design and build a radical skyscraper in just 30 month was to overlap the design with the construction.The speed at which the constructions had to be undertaken meant the engineers had to get the foundations in before they foundations in before they had fully resolved what goes on above. Even though nothing like Aldar HQ has been built up before, the engineers had to take a leap of faith and start laying the foundations without full set of plans. It put tremendous pressure on the team. Just one month after design the had started on Abu Dhabi’s round skyscraper, the construction team arrived on site to begin foundation works.
CONSTRUCTING THE EXTERNAL SHELL
Now, the engineers had to crack how to build Aldar HQ’s vast external shell. The design damaged a heavyweight shell to support it’s wide girth and survive huge wind loads. But the architect stipulated open office space, floor to ceiling window and panoramic views of the Persian Gulf.
The geometry of Aldar HQ’s shell is so complex. It must be built with the precision of a Swiss watch to fit together. On this scale, achieving millimetre accuracy with concrete is practically impossible. A wholly concrete building was never gonna work in this instance. The engineers needed another solution, the specialised steel exoskeleton called diagrid. It’s a muscular but slender steel frame that will form the HQ’s unique shape
And will channels forces through it’s high strength beams and joints in to the cores. Steel is very strong as a single element but meshing them all together gives added strength and also allows making unusual shape. Now, the challenge was a diagrid building or buildings using this diagrid system had never been built before in Abu Dhabi and the UAE.
The Army of fabricators worked in shifts around the clock to cut and weld 2500 tonnes of steel. They build a series of a ‘A’ shaped steel sections weighing up to 30 tonnes each. These were connected together to form the structure’s signature curves. Lifting these ‘A’ forms in to position on site were a major challenges. Finally, the first exoskeleton section was finally bolted to the base plate. Another 99 ‘A’ frames had to be fitted to form Abu Dhabi’s unique skyscraper.
Aldar head quarters is truely an engineering triumph. It is the first circular building of this kind in the middle East. The shape of the building acheived through the use of structural diagrid. The semispherical building comprising two circular convex shaped facades linked by a narrow band of indented glazing. This iconic fully glazed structure is completely circular in elevation and curved in all direction.
The circle symbolizes unity, stability, and rationality. It is also the symbol of infinity, without beginning or end, perfection, the ultimate geometric symbol. It represents a completeness which encompasses all space and time. The structure rises 125 meters above the Abu Dhabi sands, All, 3000 glass panels mirror the surrounding landscape, reflecting the blue skies and the rolling sea of the Persian Gulf. It is an Amazing structure.
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