At the bottom of the Burj

There is very little that hasn't been written about the Burj Dubai. Currently standing at 128 floors and 460m, it would be no exaggeration to say that this spiralling edifice, with its unique stepped design, epitomises what Dubai is striving to become - a progressive, modern, world-leading city.

Located off Sheikh Zayed Road, the Burj Dubai will also form the centrepiece of the mixed-use Downtown Burj Dubai complex, complete with the Dubai Mall, The Old Town, Boulevard and Residences. Once complete, the tower will occupy 2 million m² of the US $20 billion (AED73 billion) development. The Burj itself will hold all manner of facilities, from top-end bars and restaurants to shops and spas. An Armani hotel will occupy the lower 37 floors and the tower will also feature the Armani Residences.

While the original design met a height of approximately 700m, speculation over its eventual height remains. Project manager, Greg Sang, refuses to say anymore than confirm the tower will be over 700m, but local media reports have suggested a figure of 808m. When Construction Week visited the Burj Dubai site last week, the assumption from one of the 30 contractors operating on the tower, was that it will hit at least 800m in height once completed.

German firm Hünnebeck is one of three companies involved in the formwork for the tower - the others being Meva and Doka - and is responsible for the plan and materials for the soffit and joist formwork for the podium area. But constructing the world's tallest building is not a simple exercise, as Frank Odzewalski, CEO, Hünnebeck, explains: "We have done by far the most complex and biggest area of construction, from the podium area to various types of buildings and the first 10 floors.

"We were not aware of the volume or complexity of the work. The functional areas, such as the ballroom, are outside. The ceilings are extremely high to get concrete beams up, so everything required a lot of technical changes."

This complexity was due to the fact that every floor level necessitated different alignment of the concrete beam in accordance with the design. As a result the shuttering had to be changed for every floor sequence. Once the 10th floor had been reached, this reverted to flat, conventional slabs. Originally, the thickness of each floor slab was to be 22cm, but after consultation, this was reduced to 20cm, to ensure a greater height.

"This was part of the technical discussion taken at the beginning of the project. The slab thickness was higher but it was reduced because, with such a high tower, every centimetre you can save takes off weight and gives you the opportunity to go higher."

Highlighting the fundamental difference in construction required for the first 10 floors, as opposed to the next phase, Odzewalski explains each floor took two weeks to complete, which shrunk to just three days once the formwork continued with the regular slabs. "Every floor was different in terms of height level, so we had to use different types of support systems, and also there was a change in design in terms of beams; wide beams, small beams or high beams," he adds.

Implementing these required Hünnebeck to draw up a plan, which first had to go through the consultant - a joint venture between Turner and Hyder - who firstly checked it and then approved the go-ahead, which made it a massive administrative as well as technical task. However, Odzewalski explains that before even being offered the job, they had to convince Turner and Hyder of Hünnebeck's profile, what it had done, provide references and demonstrate technical capabilities to ensure they were happy.

"When we were asked to submit an offer to them, we were asked to provide the most suitable and possible technical solution and suitable material," he adds. Hünnebeck supplied a similar system to that in use in Europe, which is a steel panel system, which features the plywood already installed. "This is much easer to erect, more flexible in terms of length and height adjustments. It is much faster, more efficient and safer," says Odzewalski.

"These people had no clue about this system, because the market is dominated by the traditional wooden girder system, which is much slower."

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