Breaking ground on Feb. 28 in a ceremony attended by Turkey Prime Minister Tayyip Erdogan, a 5.4-kilometer twin-deck tunnel crossing beneath the Bosphorus’ seabed will join the European and Asian sides of Istanbul at a cost of $1.4 billion. Istanbul is the largest metropolitan city in Europe and third-largest city in the world, with a population of 13.2 million.
The Istanbul Strait Road Tube Crossing, or the Eurasia Tunnel, will be designed, built, financed and operated by Avrasya Tüneli Isletme Insaat ve Yatirim Anonim Sirketi (ATAS), a partnership of Yap? Merkezi from Turkey and SK E&C, Kukdong, Samwhan Corp. and Hanshin from Korea.
The Eurasia Tunnel project will be constructed between Kazlicesme on the European side and Goztepe on the Asian side of Istanbul along a 14.6-km route that includes the tunnel under the Bosphorus. Commencing from the Asian side, a tunnel-boring machine will excavate the soil 25 meters beneath the seabed to form the tubular inner walls of the tunnel. The remaining connection tunnel sections will be constructed using the New Austrian Tunnel Method. The highway project is to be completed in time for Turkey’s centenary in 2023.
The route selected for the European part of the project runs alongside the UNESCO World Heritage Site of the Historic Areas of Istanbul. The project is expected improve accessibility and contribute to reductions in traffic on minor streets throughout the historic peninsula of Istanbul, resulting in a positive impact for the World Heritage Site that includes Eastern Roman, Byzantine and Ottoman structures dating from the fourth century.
Aiming to relieve the city’s chronic traffic problems, the project foresees 75,000 cars a day using the highway once it is constructed. Currently, the European and Asian sides of the city are joined by two intercontinental suspension bridges; a third bridge is under active consideration.
The European Bank for Reconstruction and Development is considering lending $100 million to the Istanbul Strait Road Tube Crossing project, while the European Investment Bank is proposing financing of $345 million.
The Marmaray Railway Tunnel, the first undersea Bosphorus tunnel consisting of 1.4 km immersed tunnel and 9.8 km bored tunnel, runs between Eminönü on the European side and Üsküdar on the Asian side of Istanbul. Construction of the tunnel started in May 2004 and was completed in September 2008. However, the entire project, including three new underground stations and 37 rebuilt or upgraded stations, is not expected to be operational until October 2013. The project has been repeatedly delayed by archeological finds. Once operating, Marmaray is expected to increase the usage of rail transportation in Istanbul to 27.7% from 3.6%.