Bridge_project

General Rafael Urdaneta´s Bridge

Throughout history, the human race has be characterized by promoting the search and invention of tools that enable and facilitate their survival: the wheel, the computer, etc.



Some of these tools are the bridges technological tools that aim to solve the problem of crossing an obstacle in such a way as to cut down the effort and time needed to do so.



In a general notion there are 3 basic types of bridges


 * The **beam bridge**




 * The **arch bridge**


 * The **suspension bridge**

The biggest difference between the three is the distances they can cross in a single **span ****. ** A span is the distance between two bridge supports, whether they are columns, towers or the wall of a canyon. A modern beam bridge, for instance, is likely to span a distance of up to 60 meters, while a modern arch can safely span up to 240 to 300 m. A suspension bridge, the pinnacle of bridge technology, is capable of spanning up to 2,100 m.

However, there are strategic changes in these bridges that allow the creation of bridges even more technological, such as the cable stayed bridge, which consists of one or more columns (normally referred to as towers or pylons), with cables supporting the bridge deck.



There are two major classes of cable-stayed bridges: In a // harp // design, the cables are made nearly parallel by attaching them to various points on the tower(s) so that the height of attachment of each cable on the tower is similar to the distance from the tower along the roadway to its lower attachment.

In a // fan // design, the cables all connect to or pass over the top of the towers.

In Venezuela exist a example of the last kind of bridges, and for decades has been one of the longest bridge in Latin America and the world; this bridge is named like the zulian hero of the independence : General Rafael Urdaneta and is best known as the bridge over Maracaibo´s Lake.



General Rafael Urdaneta Bridge crosses the narrowest part of Maracaibo´s Lake in Zulia state, in the northwestern of Venezuela.



Its construction was raised to create better connectivity in the country and make the travel time to the city of Maracaibo shorter, since before there was only the mountain road that crossed the Andes Mountains to reach that city.

The competition to design the bridge started in 1957 and was won by Ricardo Morandi, an Italian.

Morandi's was the only concrete design out of twelve entries, and was expected to be less expensive to maintain, as well as providing valuable experience of prestressed concrete technology for Venezuela.Construction was carried out by several companies, including Grün & bilfinger, Julius Berger, Bauboag AG, Philipp Holzmann AG, Precomprimido A.C, Wayss & Freytag and K ingeniería.

Made of r einforced and prestressed concrete (a type of concrete which, before starting its working life, are applied compressive efforts in areas where tensile efforts appear under the effect of workloads) the cable-stayed bridge spans 8,678 meters from shore to shore.

The five main spans are each 235 meters long. They are supported from 92 meters tall towers, and provide 46 meters clearance to the water below.

In the realization of this work was used 3,000,000 bags of cement of 46 kg and 20,000 tons of steel, current and special.

In the period of greatest activity were employed 2,630 workers and 30% of the technicians who worked on the works were Venezuelans.



The construction of this bridge brought to Maracaibo some disadvantages such as the progressive pollution of the lake, the forgetting of tradition of building on it and the overcrowding of the city. But not everything is bad, the bridge allowed to Maracaibo to open its doors to the rest of the country, be the gateway for the export of all agricultural products from the Andes, and gave to the city the character of metropolis, who made of Maracaibo the second most important city of the country.