Bridges

     Bridges are structures that are built to get from one place to another without having to go around obstacles. Usually they span over water, cliffs, or even other roads. Different obstacles call for different types of bridges, which can vary in length, width, height, and structure. There are four main types of bridges:

Beam Bridges

 Beam bridges are simply a straight beam, usually made from wood or metal. Forces are distributed to the ends of the beam, which is distributed into the ground. Because of their ability to bend easily, they cannot span far distances.

Suspension Bridges

  Suspension Bridges are beam bridges with tall towers connected by a cable. The cable significantly takes force off the horizontal part of the bridge. This allows much longer bridges to be built.

Truss Bridges




 A truss is a structure, usually made of metal, which forms small triangles. Truss bridges are extremely useful in relieving compression and tension from heavy loads. They is also very economical because of the small amount of materials needed for a strong design.

Arch Bridges
  Arch Bridges have abutments on both sides. The force from the weight is pushed into the bridge, into the abutments, and into the ground. Arch bridges have a history of being built from stone, especially by the Greeks. Like the suspension bridge, they too can stretch long distances because of the even distribution of force.