Bridges

**_**  Bridges are technological tools that aim to solve the problem of crossing an obstacle, this means that bridges help us to cross from one side to another in technical words, and we can do it in less time and effort than without them.  Bridges make the cost of traveling decrease and that represents financial benefits, bridges allow us to travel easily across rivers… **__Types of bridges: __** __Cable-stayed bridges: __ In cable-stayed bridges the deck is supported by diagonal cables from a pylon. __Covered bridges: __ is a bridge with enclosed sides and a roof. __Girder bridges: __ is a bridge built of girders placed on bridge abutments and foundation piers. __**Movable bridges**: __ is a bridge that moves to allow passage (usually) for boats or barges. __**Pontoon bridges**: __ or floating bridge is a bridge that floats on water and in which barge- or boat-like pontoons support the bridge deck and its dynamic loads. ** Rigid frame bridges : ** a bridge where the piers or towers are connected to the girders **Tressed ribbon bridge** <span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;">:  <span style="display: block; font-family: 'Century Gothic',sans-serif; font-size: 10pt; text-align: justify;">(also stress-ribbon bridge or catenary bridge) is a tension structure (similar in many ways to a simple suspension bridge ). **__<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;">Suspension bridge: __**<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;"> is a type of bridge in which the deck (the load-bearing portion) is hung below suspension cables on vertical suspenders. **__<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;">Trestle bridge: __**<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;">(sometimes tressel) is a rigid frame used as a support, especially referring to a bridge composed of a number of short spans supported by such frames. **__<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;">Truss bridge: __**<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;"> is a bridge which load-bearing superstructure is composed of a truss. <span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;"> As we can see there are a lot of types of bridges. All bridges are made to simplify the way we cross spaces. There are pretty bridges which are also functional, but bridges are also a beauty complement to cities. Steel and concrete attached to smarter designs create works of art. <span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;"> http://clear.msu.edu/viewpoint/viewAudio.php?_ID=_t_3271_1350064250
 * __<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;">BRIDGES __**
 * __<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;"> Arch bridges: __**<span style="font-family: 'Century Gothic',sans-serif; font-size: 10pt;"> An arch bridge is a bridge with abutments at each end shaped as a curved arch.