Developing the design for the proposed 28-kilometre Yemen-Djibouti Fixed Link is the first step in connecting the Arabian peninsula with Africa. COWI has signed a contract with Middle East Development LLC in Dubai to prepare the Phase 1 design and overall requirements of the Link, 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.
Yemen and Djibouti are divided by the Red Sea's Bab El-Mandeb Strait, which itself is divided by the island of Perim. 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.
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."
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."
The scale of the project is massive. To put it in some perspective, Denmark's Great Belt Suspension Bridge has a main span of 1624m. The Yemen-Djibouti Fixed Link would require at least three spans of around 2700m each.
Henrik Andersen adds, "Because of this and our other bridge projects, we are looking to recruit experienced structural engineers."
COWI won the project by collaborating closely with colleagues in the Gulf region. "They handled the relationship with the client while we provided the specialist knowledge," Andersen explains. "It's a good example of how a local presence can work effectively with the extensive experience available throughout COWI.
The purpose of the Link will be to join two new cities in Yemen and Djibouti that are part of Middle East Development LLC's ambitious plans for the area.
Development of the Phase 1 design will be completed by summer 2008. The estimated construction cost for the bridge is in the order of US$20 billion. The total period for design and construction would be approximately 12 years.By Martyn GlanvillePublished: 12.03.2008