Beam bridges are the most simple to build bridges. It is just a beam that is supported at both ends. These were the first bridges to be used. Beam bridges are the most commonly used in highway overpasses.

Cantilever bridges are a more complex version of the beam bridge. On a cantilever there are two towers and the two bridges build out and meet in the middle. One example is the Quebec Bridge over the Saint Lawrence River.

Arch bridges are characterized by their arches that support them. They are very stable. The

y have been constructed from wood, brick, stone, steel, and concrete. The Greek, Chinese, and Etruscans used these for transportation and to carry water.

Cable stayed bridges are like the suspension bridge. There are two towers at the ends but the cables are connected directly to the towers and not to a main cable. This is good because it lacks the need of anchorages and is cheaper that a suspension bridge. An example of this bridge is the Normandy Bridge over the Seine River.

Movable bridges are bridges that can move to make room for a passing object to go under it. They are found in heavily traveled waterways. The three most common kinds of movable bridges are the drawbridge, vertical lift and the swing bridge. Modern drawbridges have two movable parts that move upward in the middle.

Some common words found in the essay are:
River Suspension, River Movable, , Iowa Floating, Chinese Etruscans, River Arch, bridges beam, movable bridges, floating bridges, bridges beam bridges, deck top, beam bridges, suspension bridges, suspension bridge, buy floating, vertical lift, swing bridge,
Approximate Word count = 539
Approximate Pages = 2 (250 words per page double spaced)