BRIDGES !!!!!

by mason waites

suspension

A suspension bridge is a type of bridge in which the deck (the load-bearing portion) is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century. bridges without verticle supsenders have a long history in many mountainous parts of the world.

arc

An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct (a long bridge) may be made from a series of arches, although other more economical structures are typically used today.

beam

Beam bridges are the simplest structural forms for bridge spans supported by an abutment or peir at each end. No moments are transferred throughout the support, hence their structural type is known as simply supported.

movable

A movable bridge is a bridge that moves to allow passage (usually) for boats or barges. In American English, moveable bridge and drawbridge are synonymos, and the latter is the common term, but drawbridge can be limited to the narrower

the history of bridges

There are many different designs that all serve unique purposes and apply to different situations. Designs of bridges vary depending on the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it.
Education - history and Bridges

The development of different types of bridges has evolved throughout history. The first bridge was likely a tree that fell or was placed across a river. Stepping stones were also used in the past to walk across rivers. This is likely one of the first techniques used in bridge-building beyond the construction of a simple beam bridge.