Bridges_presentations

** __Bridges__ ** “A bridge or a viaduct is a structure built to span a physical obstacle such as a body of water, valley, or road, for the purpose of providing passage over that obstacle”. Bridges are very old and have helped development to allow man carry many things from one place to another separated by a body of water. There are many types of bridges with different characteristics. For example: + Arch bridges  + Cable-net bridges  + Cable-stayed bridges  + Covered bridges  + Girder bridges  + Hyperbolic paraboloid bridges  + Movable bridges <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">+ Pontoon bridges <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">+ Rigid frames bridges <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">+ Stressed ribbon bridges <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">+ Suspension bridges <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">+ Trestle bridges <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">+ Truss bridges. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">

<span style="color: #444444; font-family: 'Segoe UI',sans-serif; font-size: 10pt;">The use of materials for the construction of bridges has varied through history. Before the 18th Century; bridges were made out of stone and masonry. Now, modern bridges are built in concrete, steel and stainless steel.

<span style="color: #444444; font-family: 'Segoe UI',sans-serif; font-size: 10pt;">To avoid any collapse of the bridge structure, “designers use high-performance steels that are unusually strong and tough. Among other factors, their strength allows for the creation of spans of great length and beauty that are also more durable” (WILLIAM J. BROAD. - From Fresh Ideas and Better Steel, Safer Bridges).

<span style="color: #444444; font-family: 'Segoe UI',sans-serif; font-size: 10pt;">As any structure, bridges also have advantages and disadvantages. An advantage is that the supplies of food and traded goods can get across an obstacle or through difficult terrain in a shorter time. A disadvantage is that they cost a lot of money to construct and maintain.

<span style="color: #444444; font-family: 'Segoe UI',sans-serif; font-size: 10pt;">Some examples of bridges in the world are: Brooklyn bridge, Golden Gate bridge, Marcaibo`s bridge, Pengra Road Bridge, Niederlehme Bridge and many others.

<span style="color: #444444; font-family: 'Segoe UI',sans-serif; font-size: 10pt;">In conclusion, bridges are an exceptional structure that help to communicating separated places, creating a commercial, cultural, social relation between both, or more, nations, cities, towns, etc.

<span style="background-color: #ffffff; color: #444444; display: block; font-family: 'Segoe UI','Lucida Grande',Arial; text-align: center; vertical-align: baseline;"> __**Some bridges around the world:**__

<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial,sans-serif; font-size: 15px; vertical-align: baseline;">**1.- Vasco Da Gama Bridge**
<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> "Ponte Vasco da Gama" is a cable-stayed bridge flanked by viaducts and rangeviews that spans the Tagus River near Lisbon, capital of Portugal. It is the longest bridge in Europe (including viaducts), with a total length of 17.2 km, including 0.829 km for the main bridge, 11.5 km in viaducts, and 4.8 km in dedicated access roads. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> The bridge carries six road lanes dedicated to __#|cars__, trucks and motocycles. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> The $1.1bn project was split in four parts, each one built by a different company, and supervised by an independent consortium. There were up to 3,300 workers simultaneously on the project, which took 18 months of preparation and 18 months of construction. The financing is via a build-operate-transfer system by Lusoponte, a private consortium which receive the first 40-year of tolls of both Lisbon bridges. Lusoponte's capital is 50.4% from Portuguese companies, 24.8% French and 24.8% British. As of 2009, the toll is €2.40 per passenger car (up to €10.80 per truck) northbound (into Lisbon). There is no toll for southbound traffic. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">

<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial,sans-serif; font-size: 15px; vertical-align: baseline;">**2.- Eiserner Steg**
<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> Located in Frankfurt am Main. Built in 1868-69 by the engenieer Johann Peter Peter Wilhelm Schmick and the builders: Knabenschuh & Wallot, supports J. S. Fries, iron construction. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> The bridge has (The first): <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> - Length: 174 meter <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> - Weight: 350 tons <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> - Width: 5.5 meters <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> - Height above water: 6.5 meters <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> Is a beautiful and elegant bridge. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> The base if the bridge are stone. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> Rebuilt in 1911-12. <span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;"> In 1945, the Eiserner Steg is destroyed by the second war

<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">__The Brooklyn Bridge__ is located in New York, USA, and is one of the greatest engineering constructions of the 19th century becoming in a landmark of this city.

<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">The construction of the Brooklyn Bridge started in 1869 and took 14 years to complete. This Bridge was initially designed by German immigrant John Augustus Roebling, who had previously designed and constructed shorter suspension bridges. Roebling suffered a terrible accident and dies, but before, he had placed his 32-year-old son Washington Roebling in charge of the project.

<span style="background-color: #ffffff; color: #444444; font-family: 'Segoe UI','Lucida Grande',Arial; vertical-align: baseline;">The bridge crosses the East river between Brooklyn and Manhattan.