People use bridges every single day to traverse terrain that would otherwise be inaccessible by foot or motor vehicle.
Whether used to cross valleys, move over rivers and lakes or just to avoid land barriers, bridges provide a safe and convenient way to get from one place to another without having to use additional modes of travel like planes or boats.
The earliest evidence of bridge use by humans is believed to date back to ancient Mesopotamia. Bridges were constructed in Rome using volcanic rock to make mortar, and a growing understanding of engineering principles led to stronger, longer and larger bridge structures.
Today, bridge construction can span hundreds of miles and hold huge amounts of weight as vehicles, trains and people use bridges to get from one place to another.
Longest, Highest, And Most Famous Bridges Around The World
There are plenty of long bridges in nearly every country on the planet, but what’s the longest bridge in the world? That distinction belongs to Danyang-Kunshan Grand Bridge, a structure that spans a total length of 102.4 miles.
According to China, the Danyang–Kunshan Grand took four years to construct and cost approximately $8.5 billion to complete. As the world’s longest bridge, the Danyang–Kunshan Grand carries travelers over lakes, rice paddies and canals.
It also closely follows the Yangtze River and was constructed under the guidance of the China Road and Bridge Corporation.
Although the Danyang–Kunshan Grand holds the distinction of being the longest bridge on the planet, it is not the biggest bridge in the world. In order to assign that title, it really comes down to how you classify a bridge as the biggest.
Currently, the tallest bridge in the world is the Viaduc de Millau in France. This cable-stayed bridge stands 1,104 feet at its peak and cost around $424 million to construct. If you measure a bridge’s size by height off the ground, the title goes to the Duge Bridge in Guizhou and Yunnan, China.
The Duge Bridge has a road deck that is elevated 1,850 feet off the ground.
Nearby Japan has also produced some unusually large bridges like the Eshima Ohashi Bridge. This structure has some rather steep grading and has become somewhat of an Internet meme.
Due to people taking and posting pictures of the bridge at particular angles that make the structure look incredibly steep, this bridge has a reputation for being more like a roller coaster despite grading only being at around 5.1 and 6.1 on either side of the structure.
When it comes to famous bridges, there are plenty in the world that fit the bill, but London Tower Bridge tends to be among the top contenders for the most famous bridge in the world. In the United States, the Golden Gate Bridge in San Francisco, California takes the top prize.
What Does It Take To Build The Longest Bridge In The World?
The technology and techniques used to build the world’s largest and longest bridges can be complex. Bridge construction usually takes place using suspension techniques, cables, trusses or arches.
In the case of the longest bridge, the Danyang-Kunshan Grand, construction was completed by first setting piers along the bridge’s route. Concrete girder spans were then created and placed on top of the piers.
When bridges need to cross over bodies of water, water-tight caissons first need to be sunk and filled with concrete. Towers are constructed on top of these anchor points. In the case of suspension bridges that span long distances over water, anchor points are built at both ends of the expanse that the bridge will cover.
Cables are created by spinning wires together to form a tight unit that can be made into the diameter needed for the particular weight rating of the bridge.
Afterward, the cables are hung on anchor points built into the previously-erected towers. The road deck is then created and placed in sections along the completed bridge structure.
Longest Bridges Of The Future
Although construction methods will surely evolve as the manufacturing and processing of bridge materials changes over time, one of the biggest challenges in bridge planning is the increase in heavy-load traffic.
As the Internet and global ordering have led to more and more overseas shipping and transportation, bridges of the future will need to account for an increase in heavy loads being hauled by commercial traffic. It’s believed that lightweight composite materials, often used in the aviation industry, will become part of bridge construction in the future as well.