Answer to Map #65

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Answer: This week’s map was a dot map depicting all of the suspension bridges in the world with main spans greater than 2,000 feet in length.

Currently, there are 69 such bridges. If you would like to learn more about them, Wikipedia has a handy list that you can explore. Soon, the number of long suspension bridges will grow. There are 21 bridges with spans over 2,000 currently under construction. Among these are the Maputo–Catembe Bridge in Mozambique, which will be the first long suspension bridge in the southern hemisphere, and the Çanakkale 1915 Bridge over the Dardanelles in Turkey, which in 2021 will become the world’s longest suspension bridge.

The first suspension bridge to be built with a span of over 2,000 was the George Washington Bridge between Manhattan and Fort Lee, New Jersey. When it was completed in 1931, it was more than twice as long as the previous record holder for longest bridge. Over the years, the George Washington Bridge has been expanded, including by the addition of an upper level. Today, the bridge still holds one record: its 14 lanes of car traffic are the most of any single bridge.

You can see two dots on this map in Tacoma, Washington. Those dots refer to the side-by-side spans of the Second Tacoma Narrows Bridge (completed in 1950) and the Third Tacoma Narrows Bridge (completed in 2007). There was once a First Tacoma Narrows Bridge. From 1938 until 1940, it was the third longest suspension bridge in the world, after only the George Washington Bridge and the Golden Gate Bridge. It had a design flaw that made it move vertically during heavy winds, leading construction workers to nickname it “Galloping Gertie.” In 1940, the bridge collapsed in dramatic fashion.

A quick glance at the distribution of dots on this dot map reveals that the largest density of long bridges is in Asia, particularly Japan and China. Both countries have invested heavily in infrastructure projects. As an island country, Japan relies on bridges to connect its various islands. The world’s longest suspension bridge, the Akashi Kaikyo Bridge, links Honshu and Shikoku, two of Japan’s four main islands.

In addition to having many long suspension bridges, China is home to some even longer bridges that are built in different fashions. The world’s longest bridge overall is the Danyang–Kunshan Grand Bridge, which is a railway bridge stretching just over 100 miles in length. But while the entire 100-mile path is a single “bridge,” the longest section of span is only 260 feet long—far, far less than the 2,000 feet necessary to have made our map.

Perhaps the most ambitious bridge project in the world (also not a suspension bridge) would be the final project necessary to link the cities of Shenyang and Haikou by high-speed rail. Haikou is the most populous city on the island of Hainan. In order to complete the rail link, China’s national rail network would need to complete a bridge across the Qiongzhou Strait, which separates Hainan from the mainland. Plans are in place to construct a bridge capable of carrying both trains and cars, but it would be a difficult and expensive undertaking because it would have to cross at least 19 miles of open ocean.

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