May 1, 2008 A 28 kilometer-long bridge is being planned to link the Middle East and Africa. The US$20 billion bridge will become the longest suspension bridge in the world and tower some 400 meters above the water, with at least three spans of around 2700m each. Undoubtedly set to become one of the wonders of the modern world, the project includes plans to build entire cities at each end, linked by a six-lane motorway and a four-track railway. Adding complexity to the enormous task, the bridge it is to be built in an area of intense seismic activity.

It is anticipated that the Yemen-Djibouti Fixed Link will take some 12 years to complete. Yemen and Djibouti are divided by the Red Sea's Bab El-Mandeb Strait, which itself is divided by Perim Island. The strait east of Perim is only 3.5km wide and approximately 20m deep but the western strait is more than 20km wide and 300m deep.

International engineering, environmental science and economic consulting group COWI will develop the design and overall requirements for the link for Dubai-based developer Middle East Development LLC, taking into account factors such as its location and the challenges of building in deep water heavily trafficked by shipping to and from the Suez Canal. COWI's Head of Major Bridges Henrik Andersen says, "The length and navigational clearance required west of Perim will likely mean at least 10km of multi-span suspension bridge, with the remainder being approach bridges. The concrete pylons will have to be supported up to depths of 300m and at the same time tower 400m over the water's surface to support the ultra-long span suspension bridge. Each pylon will be 700m. It will be enormous."

Andersen told Gizmag, "COWI is carrying out the intial studies of the Yemen-Djibouti project and a bridge of this unprecendented magnitude will require many studies over the next years, including such things as ship collision, seismic aspects and aerodynamics. COWI has previously conducted similar studies and design for other major suspension bridges in areas of high seismicity including the Messina bridge in Italy."

Project manager Lars Jensen has wide experience in suspension bridge design and also with the design of concrete offshore oil platforms. "Oil rigs often stand in deep water. The difference here is the weight above the water the pylons will have to bear. A rig is light compared to a suspension bridge. The pylons will have to be exceptionally strong."

AFP’s story on the proposed bridge has more details.