Technology - Bridging the Bering Strait - Extreme Engineering

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Description

A Bering Strait crossing is a hypothetical bridge or tunnel spanning the relatively narrow and shallow Bering Strait between the Chukotka Peninsula in Russia and the Seward Peninsula in the U.S. state of Alaska. In principle, the bridge or tunnel would provide an overland connection linking Asia with North America, although there is little infrastructure in the nearby parts of Alaska and Russia. With the two Diomede Islands between the peninsulas, the Bering Strait could be spanned by three bridges. Two long bridges, each almost 40 kilometres (25 mi) long, would connect the mainland on each side to one island, and a third much shorter one between the two islands, giving a total distance of about 80 kilometres (50 mi). Such length is not unprecedented, as the two long bridges each would be shorter than the 41.58-kilometre (25.84 mi) Jiaozhou Bay Bridge, currently the longest sea-crossing bridge in the world. However, the construction of a Bering Strait crossing would face exceptional political, engineering, and financial hurdles. There have been several proposals for a Bering Strait crossing made by various persons, TV-channels, magazines, etc. The names used for them include The Intercontinental Peace Bridge and Eurasia-America Transport Link.Tunnel names have included TKM-World Link and AmerAsian Peace Tunnel. In April 2007, Russian government officials told the press that the Russian government will back a $65 billion plan by a consortium of companies to build a Bering Strait tunnel. On 22 August 2011, the Daily Mail reported that the Russian government had approved a $60bn tunnel across the Bering Strait. The $60bn comes from a rough Russian estimate of $100bn. The concept of an overland connection crossing the Bering Strait goes back before the 20th century. William Gilpin, first governor of the Colorado Territory, envisioned a vast Cosmopolitan Railway in 1890 linking the entire world via a series of railways. Two years later, Joseph Strauss, who went on to design over 400 bridges, including the Golden Gate Bridge, put forward the first proposal for a Bering Strait railroad bridge in his senior thesis. The project was presented to the government of the Russian Empire, but it was rejected. The depth of the water offers little challenge, as the strait is no deeper than 55 m. The tides and currents in the area are not severe. However, the route would lie just south of the Arctic Circle, be subject to long dark winters and extreme weather (average winter lows -20 °C with possible lows approaching -50 °C, and so building activity will likely be restricted to 5 months of the year. The weather also poses challenges to exposed steel. In Lins design, concrete covers all structures, to simplify maintenance and to offer additional stiffening. Also, while there are no icebergs in the Bering strait, ice floes up to 1.8 m thick are in constant motion during certain seasons, which could produce forces in the order of 44 000 kN on a pier. In 1994, Lin estimated the cost of a bridge to be a few billion dollars. The roads and railways on each side were estimated to cost $50 billion. Lin contrasted this cost to petroleum resources worth trillions. Discovery Channels Extreme Engineering estimates the cost of a highway, electrified double track high-speed rail and pipelines, at $105 billion, five times the cost of the 50-kilometre (31 mi) Channel Tunnel.