Math in Engineering

Mathematics and Architecture

What is the world’s longest suspension bridge?

Ten years after construction began, Japan’s Akashi-Kaikyo Bridge—also known as the Pearl Bridge—was finally opened on April 5, 1998. At this writing, it still holds the title as the longest suspension bridge in the world, stretching 12,828 feet (3,910 meters) across the Akashi Strait to link the city of Kobe with Awaji-shima Island. Its main span length (or center section, which is the way “world’s longest” status is determined) reaches 6,532 feet (1,991 meters) between support columns. The span length is almost a quarter mile longer than the previous record holder, the StoreBaelt (Great Belt East Bridge) in Denmark, which also opened in 1998.

But this bridge may eventually lose its longest status if the Italian government can keep on track with building the estimated 1.3 billion Euro bridge called the Strait of Messina Bridge, stretching between mainland Italy and Sicily. The idea for such a bridge has been around since Roman times. Fast-forward to modern times, and the idea for the bridge was backed by the government in 2001; with money tight, it was scrapped in 2006. As of this writing, it has been revived again; if it is built, it will be the longest suspension bridge in the world, spanning over the strait that connects the Ionian Sea in the south to the Tyrrhenian Sea to the north. It will be quite an engineering feat, with the main span reaching just over 10,827 feet (3,300 meters), which is almost double the main span of the Akashi-Kaikyo.

Interestingly enough, Japan and Italy are known to be tectonically active, with both receiving their fair share of volcanic eruptions and earthquakes, as well as, in Japan, tsunamis (seismic waves that form in the oceans and can be tens of feet high; for more about tsunamis, see “Math in the Natural Sciences”).


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