The growth and development of population, the economic and commercial progress, have made the people to be in touch. Also, for the sales of products was necessary to build bridges as an alternative way to those people who didn´t have boats to transport their products. The bridges have been an amazing advance into the civil engineering field. As the time passed, the bridges were needed for transportation and to be used as communication routes. The bridges have been changing as needed, either to make them more efficient or innovative. Now day civil engineers are not only involved in the measuring, or resistance, but also they care about the aesthetic. There are different types of bridges that marked not only the history but the progress in society. The bridges vary depending on the material with which it is built and the shape they have.
Types of bridges:
Wood: These bridges are quick to build, and are not too expensive, yet are very resistant and durable, plus they need constant and expensive maintenance. For the ease of being built and cheap were the first bridges that people used. Stone: They are very resistant, compact and durable. Currently construction is very expensive. They do not need much maintenance, since they are very well resistent weathering agents. Metallics: They are built quickly, are expensive and have corrosion as an against factor. Also, their maintenance is expensive. Concrete and steel: They allow varied designs, often support precast, they are resistant, and maintenance costs are low. The functions that bridges have are:
Aqueduct: They are used for water conveyance.
Viaducts: They are built to have automobile transit.
Footbridges: Built for the use of pedestrians only.
The way bridges resist their efforts:
Beam: They consist of horizontal elements that are supported at their ends on supports or pillars. The force transmitted through the pillar is vertically downwards and, therefore, they are subjected to compression, the beams (horizontal elements) tend to bend as a result of the loads on. Arc: It has 2 divisions. Top board, and Lower board. They consist of a curved section which rests up on supports or brackets and covering a light or empty space and depending on whether they are above or below the board, is where the arcs are located. Hanging: They consist of a board by hanging by a large number of straps, two large cables that are anchored at the ends of the bridge and held by large towers of concrete or steel. Conclusion:
The bridges have served as communication routes, and have had a lot of impact on society and commerce. Bridges are very important in the area of civil engineering, because their work as engineers is to build and make sure that their work is good to use, and efficient. In addition, the bridges have made the civil engineer to worry about the design of buildings and to show them that is important the aesthetic and how innovative is the work.