Palm Jebel Ali bridge to 'float' above water

Dubai, Aug 3, 2008 (WAM) - The final design and structural design for the iconic bridge to The Palm Jebel Ali has been handed over to Nakheel by the architects Royal Haskoning.

Speaking exclusively to 'Emirates Business' yesterday, Syb van Breda, the firm's director of architecture, said: "We have delivered the final design and structural design to Nakheel. The requirement was to design a truly iconic bridge – something the world hasn't seen before." The project involves creating an eight-lane motorway connecting Dubai's largest Palm Island at Jebel Ali, with the waterfront. "Nakheel will be tendering the project," van Breda said. The initial design involved a six-lane motorway.

The bridge will be supported by 72 stay cables between two 135-metre high pylons and include pavements for pedestrians and cyclists. In December 2006, Nakheel held a design competition and shortlisted three firms. Royal Haskoning were intimated in February 2007 that their entry had won.

The bridge is expected to become yet another landmark in Dubai. "This is a very important part of the project since it is the entrance to The Palm Jebel Ali," said van Breda. "There have been changes to the design from the concept stage when we won the competition. But that is what we call an optimisation of the design." There was another major change – in the final client brief. "Initially, the design brief asked for a six-lane motorway. We were then asked to change it into an eight-lane one," he said. Van Breda said the challenge proved to be beneficial to the structure.


"When we were asked to widen the roads, we thought it seemed structurally impossible and the pylons would not be able to bear the load. But we sat with the best engineers and conducted many peer reviews. We found out that it had actually become more feasible to build this bridge and the change in the design would actually make the deck more stable. We discovered that, apparently, the wider the deck the more stable the bridge."


The bridge is said to float above the water. "The bridge is not floating literally, but only in a poetic way," said van Breda. "The location is a great open water body, separating the distinctly different worlds of Dubai Waterfront on one side and The Palm Jebel Ali on the other. So the bridge is the moment and the place where the two are linked."


The solution was a world's first, he said. "This site requests a powerful profile and a cable-stayed bridge is the answer. Not just any cable-stayed bridge, but one where the deck and the pylons are fully separated. This creates a very spectacular floating image, and is a first in terms of its structural solution," said van Breda. "We have separated the pylon from the deck and the only connection in this structure will be the web of cables itself," he added.

Bridge design, according to van Breda, is usually straightforward. "In this project, the pylons themselves become a sculpture," he said.

Innovations in 3D technology have greatly assisted this project. "The shapes themselves are not just complex but would have been impossible to calculate structurally. With the current advances in computer technology over the past 15 years, it is now possible to produce 3D elements into structural shapes," said van Breda. "The pylons and the deck edges are designed as complex curves that will reflect the abundant Gulf daylight in a beautiful way," he explained.

"Structurally, a cable-stayed bridge stabilises itself so it is
ideal for this project given the nature of its location."

In terms of materials, the bridge will be a hybrid of steel and concrete, he said. Royal Haskoning has been in the UAE since 2003. It is working on a wide range of engineering and architectural projects on the three Palm projects and The World. Other projects include water taxis with the Dubai Roads and Transport Authority and industrial buildings in Dubai Maritime City.– Emirates Business 24|7