Bridge_Project

ORINOKIA BRIDGE

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Hello, my name is Kelly Cabarcas, urban planner. I am going to talk about bridges. Bridges are tools which connect two points that are generally separated by natural obstacles such a body of water, a hill and other. Bridges are designed according to the needs, obstacles to be crossed and distances to be connected. A bridge could be designed for pedestrian or road traffic water transport, barge traffic or only for trains. For this reason we find several types of bridges according to their structure or use.

STRUCTURE

Beam bridges: They are horizontal beams which are supported at both ends by piers. In fact, the simplest beam bridges are simple logs that sit across streams. Nowadays, they are large box steel beam bridges.

Cantilever bridges: They are constructed using “cantilevers”, which are horizontal beams that are supported only at one end. Most of these bridges are two cantilever arms extending through the obstacle from contrary sides, meeting at the center with a suspended span, supported only by the two beams.

Arch bridges: They are arch shaped, naturally, and have abutments at each side. The weight of the whole structure is supported by the abutments at both ends.

Suspension bridges: These bridges are suspended from cables. The first suspension bridges were built with ropes or vines covered with bamboo. Nowadays, the cables hang from towers that are attached to caissons which are implanted into de floor of the river or lake.

Cable-stayed bridges: Very similar to suspension bridges, cable-stayed bridges are also held up by cables. The difference is that in these bridges you don’t need as much cable and the towers holding the cables are much shorter.

Truss bridges: These bridges are composed of several joined elements. At the beginning, these bridges were made of wood with iron tensile rods, but modern ones are made of metals such as wrought iron, steel or even concrete.

USE

Aqueduct: This is a bridge that carries only water.

Viaduct: This is a bridge which connects sides of equal height.

Now that we know a bit about bridges, now we can discuss a more specific case, the bridge over the Orinoco River, better known as the “Orinoquia Bridge”.

LOCATION

The Orinoquia Bridge was built near Ciudad Guayana, in southern Venezuela. This bridge joins the states of Bolivar with Anzoátegui and Monagas, becoming the second structure to be built over the Orinoco River, after the Angostura Bridge. It is a mixed bridge (road-rail).

TYPE OF BRIDGE AND MATERIALS

According to the classification mentioned above, the Orinoquia Bridge is a suspension bridge, made of concrete and steel; and, according to the use classification, it is a viaduct. It is one of the most important infrastructures in the area.

It extends for 3,156 meters and it has four main towers, which are 120 meters height; also it has 39 batteries reaching up to 87 m depth, two brackets, 388 piles, headroom on the maximum water level of 40 meters and a total width of the board of 25 meters, with four flow channels plus a rail trail. A metal superstructure, consisting of 272 modules is responsible for supporting the circulation channels and is reinforced by a cable-stayed span of 1200 meters. Concrete 179 cubic meters, reinforcing steel 35 cubic meters, steel structures 25 tons and 2.253 cubic meters of embankment construction. It also has:

· Highway connection from Ciudad Guayana to Ciudad Bolivar: 6 km and 4 channels of 3.6m. · Connection from Los Pozos in Monagas: 35 km and 2 channels of 3.60m · From La Viuda in Anzoátegui to the bridge with a speed of 125 km with 2 channels of 3.6 m. · The mixed bridge (road-rail) on the Orinoco River is a braced type with fan settings and H-shaped towers.

DESIGNERS

The project starts with the early viability studies, conducted by CVG - Corporacion Venezolana de Guayana, in 1966, for the construction of a bridge in Ciudad Guayana. Localization studies were performed, also, topographical, geological, structural solutions, transport, urban development, regional studies and economic and financial viability. These studies took place in a total of eight locations which are situated between East and West San Félix Sidor.

The final decision on construction begins with the order of the President Hugo Chávez of Venezuela in 2001. The design of the bridge comes from the hand of legendary engineer “guayanes” Paul Lustgarten (also, he designed the Rafael Urdaneta bridge and the first bridge over the Orinoco River, the Angostura bridge). The Brazilian construction company Odebrecht was the capital provider and most of the national executive came through Fonden (National Development Fund).

TECHNOLOGY INVOLVED IN ITS CONSTRUCTION

The execution was not simple, since in our country there was no experience in building works of this scale. It was, therefore, necessary that the workers who participated in the construction of the bridge had an intensive preparation.

Professionals, technicians and skilled workers had to soak in sophisticated procedures, such as the slipform "new method" used for the construction of batteries. The four towers of 120 meters, which are along the bridge, needed a year to be build.

The metal superstructure that supports the flow channels, comprising 272 units, was fully assembled in the country and promoted the revival of the metalworking industry in the region that was operating between 20 and 30 percent of its capacity.

ADVANTAGES AND DISADVANTAGES OF THE BRIDGE FOR THE SPECIFIC COMMUNITY

· The rail transportation provides transportation to the rest of the country and to the export ports of iron products, steel, aluminum and wood of the Guayana region.

· One of the main benefits that comes from the bridge is that it reduces the travel time between the states of Anzoátegui and Monagas, located at north of the river, with Bolívar, located on the south side of the river.

· Among the most favored locations we find Ciudad Guayana, since before the bridge, the only way to reach this city by car from Monagas was through a wooden barge that crossed the Orinoco. With the second bridge over the river, the journey from Maturin is one hour and 30 minutes, explained Lucas James, coordinator of the project by the Corporación Venezolana de Guayana.

· Also, to go from Barcelona, for example, the drivers took four and a half hours to get to Ciudad Guayana, they had to cross the Angostura Bridge and then travel along a highway. Now the journey is one hour and 15 minutes.