The Suspension Bridge!
A suspension bridge is a bridge which has the roadway suspended by cables that are anchored at either end which are most of the time supported at intervals by towers. These towers support the majority of the weight as compression pushes down on the bridge's deck and then travels up the cables to transfer compression to the towers. Suspension bridges are lightweight but strong which can be as long as 2,134m, however they are also some of the most expensive types of bridges to construct.
How does a Suspension Bridge work?
the main cables are attached to the vertical cables which attach to the deck. These cables support the deck of the bridge which transfers the weight to the towers at the end. The main cables continue past the towers and are anchored past the far ends if the bridge. They are carefully balanced so that the force pulling inward is equal to the force pulling outward. As a result, the weight pulls directly down into the base of the tower. The towers and the deck can be fairly thin since the towers aren't being pulled to either side and the deck is supported by cables.
History of the suspension bridge
Suspension bridges have been used for thousands of years. The first suspension bridge which was built in 1816 was temporary footbridge in Philadelphia. The Niagara Falls suspension bridge which was built over the Niagara River in the USA was the first working railway suspension bridge with a total length of 251m.
Golden Gate Bridge
The golden gate bridge in San Francisco is a perfect example of a suspension bridge. It is 2,737m long and is 227m high. The golden gate bridge was opened in 1937 after a four year struggle against relentless winds, fog and treacherous tides. The golden gate bridge is commonly made up of steel and concrete and the bridge itself cost $35million to build.
Other examples of Suspension bridges
The Tower Bridge is a 65m high bridge in London.
The Brooklyn Bridge is a 1,825m long bridge in New York City.
The Akashi Kaikyo bridge in Japan is the world's longest suspension bridge with a total length of 3,911m.