Bridges

Suspension bridges are considered to have first been invented in 1595 by Fausto Vernazio. However the first American iron chain suspension bridge is considered to be the Jacob’s Creek Bridge in Pennsylvania, built in 1801.

 

They work by using 3 main parts: the cables, deck and towers. The cables, specifically the vertical suspender cables or hangers, support the weight of the traffic that passes over the deck. These cables are attached to towers which are mounted in the ground or water below the bridge. The main cables are then fed into anchors in the ground on either side of the bridge.

 

The suspension bridge is built to handle three main types of forces: dead load, dynamic load and live load. The dead load is caused by the weight of all of the materials used to build up the bridge. The dynamic load is any environmental factors like wind or water. The live load is caused by the weight and movement of the cars and people traveling over the bridge.

 

The longest suspension bridge in the world is currently located in Japan and it is called the Akashi Kaikyo Bridge. It is 6,532 feet long and took 12 years to build.