Bridges_notes

= = =   = The bridges are tools that allow us to connect two points, so make a trip in less time, and carry things with less effort.
 * __BRIDGES __**

 The evolution of the bridges has been thanks to the development of constructive knowledge of architects, engineers, and what at first might be a discovery by an appearance in nature, as I could be a fallen log, nowdepends on analysis of the materials to be used, the efforts that will be answered by the persons or means of transport that use of wit and aesthetics that is designed, costs that can cover for construction, etc. . Thus, for example, an essential element in deciding the type of bridge design, is to have good knowledge of the soilwhere it will be implemented, and physical conditions that may cause impairment.

The bridges can be classified according to use, material or shape.

As used, we can divide the bridge into the following types: __Aqueduct:__ When the goal is to transport water from the bridge. __Viaduct:__ When used as a road or railroad. __Routers:__ When are exclusively for the movement of people.

With material we divide bridges: __Wooden bridges:__ They are fast and economic construction, but are less resistant to weathering, because the water and wind modify their physical properties, weakening it. __Stone bridges:__ bridges are very strong and used since the technical mastery of the arches, but now not performed because of its high cost. __Metal bridges:__ They are very versatile, rapid construction, allowing long spans, but are very expensive both in construction and maintenance, because the metal is exposed to high corrosive agents. __Reinforced concrete:__ They are building fast because you can use prefabricated elements are low cost and low maintenance because they are resistant to environmental agents. Their lights are greater than those of the stone bridges, but lower than that of steel bridges.

Depending on how we can divide the jumpers on the following: __Arch bridge:__ This consists of the repetition of elements known as semi-circular arches supported by pillars. This type of bridge work only in compression. These bridges divide the weight on the supporting pillars, arches continuous and firm support. <span style="font-family: 'Comic Sans MS',cursive;">