MARMARAY TUNNELLocation: Istanbul, TurkeyPrice Tag: $3.3 billionCompletion Date: 2010Total Length: 8.25 milesImmersed Section: 4600 feetSince the 19th Century, Turks have dreamed of connecting Europe and Asia via a tunnel under the Bosporus. Soon, that dream will come true in the form of the 8.25-mile-long Marmaray Tunnel, which will provide a rail link for a rapid transit system.Tunnels on such a scale have been built before, but the Marmaray engineers had to deal with an extra hurdle – they’re working in an earthquake zone. According to seismic experts, the nearby North Anatolian Fault has a 62 percent chance of generating a strong quake within the next 30 years. The solution: While most of the tunnel will be bored through solid rock, the central mile-long section under the Bosporus will consist of an “immersed tube” fabricated in sections on the surface and then sunk and joined together on the seabed. Unlike a tunnel bored through rigid rock, the submersed sections will be connected by flexible joints made of thick, rubber-reinforced steel plates, which can absorb quake movement without breaking. When it opens in 2010, the Marmaray will be the deepest such tunnel ever constructed, with a maximum depth of 180 ft. And, East and West will meet without getting their feet wet.Sizing Up: Tunnels>Media Platforms Design TeamMedia Platforms Design TeamMedia Platforms Design Team bgcolor="#ed1c24" style=“font-color:#ffffff; padding:2px; border-right:1px solid #cccccc”>SEIKAN TUNNEL Claim to fame: Longest, deepest rail tunnel Location: Japan Date completed: 1988 Length: 33.5 miles Maximum depth: 787 feet bgcolor="#ed1c24" style=“font-color:#ffffff; padding:2px; border-right:1px solid #cccccc”>CHANNEL TUNNEL “CHUNNEL” Claim to fame: Second longest rail tunnel Location: England to France Date completed: 1994 Length: 31 miles Maximum depth: 246 feet bgcolor="#ed1c24" style=“font-color:#ffffff; padding:2px;">LAERDAL TUNNEL Claim to fame: Longest road tunnel Location: Norway Date completed: 2000 Length: 15.2 miles Immersed tunnels are built in sections, floated to the site of assembly (A), then sunk to the seabed (B). More than 35 million cu. ft. of soil, sand and gravel will be dredged from the floor of the Bosporus for the project.Jeff WiseJeff Wise is a New York-based science journalist specializing in aviation and psychology. He is the author of The Plane That Wasn’t There: Why We Haven’t Found MH370.
