Suspension Bridges

"The Moving Bridges"

Structure

Suspension Bridges are types of bridges which have road-way suspended by cables (two or more) which ,most of the time, pass over towers strongly anchored at the ends. Suspension Bridges are mostly used to span long distances. A unique thing about Suspension Bridges is that, because of their weight, they move around so the builders have to be very careful about building them so that they don't fall over.



First Suspension Bridge

The first Suspension Bridge. This is a debatable topic as different people have different classifications of suspension bridges. People from South America and the Himalayas used rope or wire suspension bridges to go across chasms (deep cleft in the earths surface) since ancient times but some people don't classify those as suspension bridges.


Although there is no oldest suspension bridge an old one is Clifton Bridge which came around in 1754. So it is about 259 years old. It is located in the city of Clifton in Bristol and is used to go over River Avon.


Golden Gate Bridge

One of the most famous suspension bridges in the world is the Golden Gate Bridge. It is located in San Francisco running into the Pacific Ocean. A suspension bridge was used for this project as they needed quite a long bridge and ,as mentioned earlier, suspension bridges are mostly used to cover long distances.


Materials

The anchors of a suspension bridge are usually made out of concrete as it is durable, strong, cheap and is made all around the world. The cables which keep the bridge from sagging (drooping or hanging loosely) have to be extremely strong as they undergo a lot of tension and compression, so they are made of steel which is one of the strongest metals. The towers of the suspension bridge can be made of many things such as steel, iron or even stone like the Clifton Bridge.


Disadvantages

Building a suspension bridge can not be done as quickly as some other bridges. Because it moves around or vibrates when there is too much wind, it takes a lot of planning and time so it can't be rushed.