Bridge_project

First of all, we have to know what a bridge is. A bridge is a link or connection between two objects - usually places either side of an obstacle, such as a river, chasm, or estuary. Across gulfs and rivers, between peoples and countries, bridges break down separation and foster connectedness. Some of the benefits of bridges are obvious: supplies of food and traded goods can get across an obstacle or through difficult terrain in a shorter time. There are some types of bridges, as we now: This is the earliest and simplest kind of bridge: a fallen tree lying over a stream, perhaps, or a log lodged across a narrow chasm? We still come across these when walking in the hills, and there is no way of dating the first time some hominid straightened or stabilized such a 'beam' and thereby became the world's first bridge engineer. All beams tend to 'sag' between the piers and 'hog' over the piers themselves. This results from the downward forces of the load and the upward forces at the pier supports. The greater the span or the load, the greater the tendency towards sagging and hogging. To create beams that have the effect of being very deep but don't weigh much, ingenious nineteenth-century bridge designers in the United States added supporting latticework, or a 'truss' to the bridge's beam. There are many subtle variations on the truss, with the name of each variation immortalizing its inventor.
 * 1) 1. The beam bridge

The arch is really a beam curved to form a semicircular shape, which is prevented from straightening and spreading sideways by strong 'abutments' at either end. One disadvantage of the arch is that it needs firm support from the sides. If there are no abutments or banks to build against, the arch will spread and collapse.
 * 1) 2. The arch bridge

A suspension bridge is one where the road deck is suspended from cables that are strung across the river (or whatever the obstacle happens to be). There is no support in the center of the span and the deck hangs below the supports rather than resting upon them.
 * 1) 3. The suspension bridge

One example of disadvantages of suspension bridges is the Tacoma Narrows Bridge that unfortunately, it displayed rather too much grace and flexibility, becoming known as 'Galloping Gertie' for the wave-like motion of its deck, even in light winds. In the cable stay version of the suspension bridge, the deck is hung from diagonal cables that exert a force towards the towers as well as vertically. This makes the tension in the steel cables extremely high, and hence they are very stiff. In addition, the cables effectively stabilize the towers from both sides.

In summary, it looks like the future has two faces, as far as bridges are concerned:
 * The mass-produced bridge built to standardized designs using cheap and readily available materials like concrete and steel. 'Functionality' is the keyword where quantity is concerned, and 'quantity' is the keyword when a typical stretch of new motorway can require building a new bridge every mile or so. We can expect to see dull but dependable beam bridges across our roads and railways for a good while yet.
 * The 'one-off' iconic bridge, such as those commissioned for Millennium projects throughout the world. Many cities like the idea of building an innovative bridge to symbolize their modern outlook and their openness to certain ideas of the future. These 'one-off' bridges are often designed as much for their form as for their function, and public competitions are frequently held to choose a suitably impressive-looking addition to the city skyline. Eco-friendly planners away from the City also like the idea of Nature being complemented by high-tech, low-impact bridge designs.

But the technology and the progress of our times have brought us to improve the bridges, and has increasingly made ​​the creativity of the designers (architects, engineers, etc.) to another level, as an example we have the chosen bridge, Moses Bridge. Creative pedestrian bridge near Fort de Roovere in Halsteren Netherlands, divides the water like Moses and allows people to safely cross to the other side. It’s designed by RO&AD architects, this unique trench inspired sunken bridge was constructed out of extremely durable Accoya wood. A series of moats and fortresses were built over the West Brabant Water Line region of the Netherlands during the 17th century in order to provide protection from invasion by France and Spain. Fort de Roovere was surrounded with a shallow moat that was too deep to march across, and too shallow for boats. In turn the earthen fort had remained protected –until now. From afar, the Moses Bridge is invisible to the eye. The flow of the moat appears continuous, as the water level remains at the same level, reflecting the surrounding foliage. As visitors approach the fort, the bridge appears as a break in the water with its sloping walls containing it. First place is at ground level, but then drops to crawl deeper water. To achieve this, the structure is anchored to the ground by steel piles, the entire structure is covered with Accoya wood, a material specially treated waterproof the bridge and can resist erosion by the stream, protecting it from fungus and increasing its durability. It was recently recognized by the Dutch Association of Architects as the best structure for 2011. Also, is among the finalists for the Dutch Design Awards 2011. Is not a surprise all the advantages that the bridge has, such as communication between two sides, that it’s invisible to our eyes that is not perturbing the context and integrates to the nature. But bad news are always around, and we don't doubt about a great bridge it is, but as we now, Netherland is under water and every year the water level of the ocean increase, so we wondering if someday the bridge will be submerged?

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