In Kolkata Vidyasagar Setu is known as the second Hooghly bridge. It is a beautiful bridge over the river Hooghly. Vidyasagar Setu is suspended 457 meters above the river Hoogly. This bridge is beautifully lit at night. The Vidyasagar Setu is one of the symbols of the city of Kolkata and one of the most famous bridges in the world. Crosses the river Hooghly in its narrowest point.
The evolution of the structural system and the widespread use of suspension bridges was due to the Seguin brothers. In particular, Marc Seguin introduces the use of metal wires instead of "chains" forged, as well as many other tricks and refinements that concrete in the construction of the bridge to Tournon in 1825.
The company was founded with his brothers Camille, Jules, Paul and Charles, builds a large number of bridges over 65 in France and also in Spain and the two suspension bridges of Florence, San Leopoldo bridge and bridge San Fernando, built between the 1836 and 1837, both disappeared. He dealt with suspension bridges also Henri Navier , a pioneer in building science and the theory of elasticity that writes a treatise on suspension bridges.
In 1998 it was opened to traffic on road largest suspension bridge in the world, the Akashi Kaikyo Bridge in Japan , whose main span measuring more than a mile (1,991 m). In 2011 was supposed to begin construction of the bridge Strait of Messina , which, if it is implemented in accordance with the project contract, it would be the longest suspension bridge in the world with a single light climbing over 3,300 m wide strait.
The cables that make up the inverted arch of suspension bridges must be anchored at the ends of the bridge, as they are instructed to transmit an important part of the load that has to bear the structure. The deck is usually suspended by vertical tie rods which are connected to said cables. The cables of a suspension bridge form a curve very similar to a parabola