trailer world Issue One 2013

10 Issue One 2013 Reportage »In an earthquake, the tunnel would be the safest place you could be.« Selami Isik, structural engineer with Avrasya Consult Photos:AgataSkowronek,SusanneLandwehr the tunnel in the direction of Europe, un- til we are standing under the waters of the Bosphorus. The skeletal work is almost fin- ished, now activities are focussing on the rails. In mid-January, the site was visited by the Turkish prime minister in order to in- augurate the first tracks. Standing on a red carpet, he stepped through the tunnel and announced in his speech: “The Marmaray Tunnel is not just a Turkish project, it is a global project.” The first thoughts about such a project came about in 1860 when the Ottomans dreamt of a connection between the continents. However this has now only become technically possible. It is backed up by a Japanese-Turkish consortium: Due to the geographical location and depth of the Bosphorus, the planners decided to dig a trench into the sea bed and install the tun- nel elements in that. During 2007 and 2008, a total of eleven tunnel sections were built in the Turkish shipyard city of Tuzla on the Asiatic side of Istanbul. These sections were made from cement, and the longest was 135 metres in length with a weight of 15,000 tonnes. “Following their production in the shipyard, a special ship towed the elements through the Sea of Marmara to the building site, where they were sunk,” explains Sela- mi Isik, structural engineer of the consult- ing company Avrasya Consult. The special challenge, he continues, concerned dealing with the powerful currents in the Bospho- rus – and the shipping. The tunnel elements were fitted with a GPS system in order to al- low them to be placed correctly. The tech- nicians could follow on a screen what was happening 60 metres down. The complete journey from the shipyard to the bottom of the Bosphorus took about six days for each tunnel element. 60 metres down under the wa- ters of the Bosphorus “We achieved a world record with two el- ements,” says Selami Isik. Never before, af- ter all, had anyone sunk tunnel elements in such deep waters. Of the total network cov- ering 76 kilometres between Halkali on the European and Gebze on the Asian side, 1.4 kilometres are under the Bosphorus. A fur- ther 9.8 kilometres has been dug by a total of five tunnel drilling machines. The drilled and sunk tunnel sections were connected on both sides using a special rubber-like material. “They also function as earth- quake protection, because they can absorb the power of the shocks,” says Selami Isik. The entire tunnel, he continues, has been designed to withstand an earthquake of 7.4 on the Richter scale without damage: “In an earthquake, the tunnel would be the safest place you could be.” The capacity of the tun- nel is for about 75,000 passengers per day, while freight trains will use the connection at night. “It has not yet been clarified when precisely the cargo trains will run,” says Gökhan Göker, safety expert of the Taisei Group. The freight trains should be able to use the line from about midnight until five or six in the morning. “The Ministry of Transport is planning to build goods tran- shipment centres on both sides of the tunnel to allow for loading from rail to truck and

trailer world Issue One 2013

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