The Vasco da Gama bridge can be safely added to the list of modern wonders of the world. It is located in the northeastern part of Portugal near Lisbon.
Vasco da Gama was known as the Portuguese navigator of the Great
Geographical Discoveries. In 1497, the traveler, together with the expedition, went in search of the sea route to South Asia from Europe. The trip was successful: Vasco da Gama discovered the southeastern coast of Africa, from which the further route led to India through the Indian Ocean. In 1499, the expedition returned with great triumph to its homeland, led by the winner. For great services to the fatherland, Vasco da Gama was appointed to the post of Viceroy of Portuguese India.
The name of the discoverer, it was decided to name the bridge connecting the coast of Portugal through the Tagus River (or Spanish. Tagus). It is the largest in the entire Iberian Peninsula. The river begins in Spain, passes through the whole of Portugal and flows into the Atlantic Ocean near the capital of the country - the city of Lisbon. The Vasco da Gama bridge was conceived as a grandiose and large-scale target object. The feasibility of building a bridge was dictated by the urgent need to unload the traffic flow in Lisbon on the April 25 Suspension Bridge.
The design of the new bridge was entrusted to the development of a group of architects led by Michel Verlauche. They faced a difficult task - to connect the banks of the Tagus River, separated by a distance of more than a dozen kilometers, taking into account the high seismic hazard of the area.
Vasco da Gama bridge: design features
The authors created a bridge project consisting of several sections, structurally different from each other. The longest part twelve kilometers long looks like a cable-stayed, or suspension, bridge. High reinforced concrete pylons are connected to the road with cables - steel straight cables. The height of the pylons reaches one hundred and fifty meters. The largest span of the cable-stayed bridge is four hundred and twenty meters. In addition, the height of the road relative to sea level is forty-seven meters. Such parameters do not impede the free passage of river vessels.
The cable-stayed bridge ensures the immobility of the roadway. The lightweight road surface is attached separately from the pylons, which prevents the destruction of the bridge during seismic vibrations and gale. The design is resistant to wind loads of up to two hundred and fifty kilometers per hour. The Vasco da Gama bridge will withstand the fluctuations of the earth's crust, the strength of which is four times greater than the earthquake with a shock of up to nine points, which occurred in Lisbon in the middle of the eighteenth century.
In the initial and final parts, the bridge goes into a viaduct - a bridge structure on piles. The distance between the supports in different places is from forty to eighty meters. Piles go under water to a depth of one hundred meters.
The total length of the Vasco da Gama bridge is seventeen kilometers two hundred meters. Taking into account the considerable length of the overpass, when designing it, the roundness of the surface of the globe was taken into account in the calculations. Otherwise, a difference of eighty centimeters would have arisen between the height of the northern and southern ends of the bridge. The developers determined the
warranty period for the unique design - one hundred and twenty years.
Highways
Thirty meters wide highway was laid across the bridge, along which traffic is organized in four lanes in each direction. Three bands are constantly involved, the fourth is opened at the moments of maximum traffic flow intensity. The maximum vehicle speed is one hundred twenty kilometers per hour. Only one of the sections of the bridge is not allowed to go faster than a hundred kilometers per hour. Under adverse weather conditions it is required to reduce the speed to ninety kilometers per hour.
To organize preventive measures to maintain the bridge in proper position, drivers moving towards the capital will be charged a fare. The cost is determined depending on the type of vehicle and ranges from two and a half to eleven euros.
Aesthetic features of the bridge
The authors of the project attached great importance to the aesthetic component of the bridge structure. To minimize the impact on the natural environment, the bridge was laid in a wide place of the river.
The viaduct, located on the south side, was erected at a considerable distance from the coast, so the coastal zone has undergone minimal bottom damage. Lighting is designed so that glare from lamps at night does not reflect on the surface of the water.
The timing
The Vasco da Gama bridge was created in record time. From the moment of development of the project of a grandiose construction to its commissioning, only three years have passed. Half of this period was occupied by preparatory work. More than three thousand builders took part in the construction of the giant's construction. The four largest construction companies provided uninterrupted work with their own technical resources of the latest developments. The construction of a powerful transport artery cost the state nine hundred million euros.
Opening
The grand opening of the large-scale construction took place on March 29, 1998 on the eve of the Expo-98 exhibition. A significant event was timed to the 500th anniversary of the discovery of the sea route by the traveler Vasco da Gama, in whose honor the super bridge was named.
Looking at the elegant, huge structure, the viewer gets the impression of airiness and weightlessness of the structure, attracting itself to an infinite distance. When traveling in Portugal, you should definitely visit such a famous place as the Vasco da Gama bridge, a photo of which will forever leave in your memory the most powerful and bright emotions. The grandiose building amazes with its beauty at any time of the year, equally impressive on a sunny day and a dark night, on a cloudy morning and on a crimson evening.
Conclusion
The title of the longest European bridge rightfully received the Vasco da Gama bridge. Portugal can deservedly be proud of the unique building, introduced by the world community into the treasury of the greatest architectural achievements of mankind of the late twentieth century.