Howrah Bridge, Kolkata: Spanning River Hooghly and connecting Kolkata to its twin city – Howrah is the spectacular Howrah Bridge - a Cantilever Bridge that is the symbol of Kolkata and is known as the Gateway to Kolkata, the Capital City of West Bengal State of India.
Positioned at 22.58527°N, 88.34694°E, the Howrah Bridge is also popularly known as ‘Rabindra Sethu’ after West Bengal’s great poet and India’s first Nobel Laureate for Literature – Rabindra Tagore.
A brilliant structural and technological marvel, the Howrah Bridge is a majestic and a very imposing structure which is a feast to the eyes. It is reckoned as one of the finest Cantilever Bridges in the world. The best way to view this bridge is from the centre – therefore from a ferry on the river which offers panoramic views of the bridge. The Howrah Bridge has been a source of immense inspiration to engineers, architects, poets, writers, lyricists, photographers and film makers.
The Howrah Bridge is a suspension type balanced cantilever bridge with central span of 1500 feet – an eight-lane bridge with two footpaths of 15 feet on either side. The Bridge deck (carriageway) is 71 feet wide.
There are 46 Cantilever Bridges (that carry people, automobiles or trains) in the world - the Howrah Cantilever Bridge being the 6th longest Cantilever Bridge (1500 feet long and commissioned in 1943) after – Pont De Quebec in Canada (1800 feet long, completed in 1917); Forth Bridge Edinburgh, United Kingdom (1710 feet long, completed in 1890); Minato, Bridge in Osaka Japan (1673 feet long, completed in 1973); Commodore Barry Bridge in New Jersey, United States (1644 feet long, completed in 1974); Crescent City Connection in New Orleans, Louisiana, United States (1575 feet long, completed in 1958 eastbound and 1988 westbound). This list does not include pipeline bridges, cable-stay bridges, suspension bridges or footbridges. The first modern Cantilever Bridge in the world spans River Main in Germany, and is called the Hassfurt Bridge with a central span of 124 feet.
The Howrah Bridge is one of the 4 bridges across River Hooghly, the others being – The Vidyasagar Setu (also called the ‘Second Hooghly Bridge’, is the longest cable-stayed bridge in India and one of the longest in Asia and was commissioned in 1992), The Vivekananda Setu (also called the Bally Bridge and the Willingdon Bridge – is a multispan steel bridge commissioned in 1932) and the Niveditha Setu (also called the second Vivekananda Setu – is a cable-stayed bridge and India’s first multi-span, single-plane cable-supported extra-dosed bridge, commissioned in 1932).
In 1874, a Pontoon Bridge (a bridge that floats on water) was commissioned on River Hooghly in order to meet with an increasing requirement of the fast-growing traffic of Kolkata that needed to cross the bridge daily. The Pontoon Bridge was designed by an English Civil Engineer who specialized in Bridges – Sir Bradford Leslie. He also has to his credit, his most notable achievement – the Jubilee Bridge (a rail bridge) 1887, on River Hooghly between Bandel and Naihati. The Howrah Bridge was constructed by Cleveland Bridge & Engineering Company – a British firm.
As the Hooghly River was prone to high-tides, the Pontoon Bridge had become risky especially for the hundreds of bullock carts which constituted a majority of the vehicular traffic on the bridge. Silting problems were also feared. And the rapid increase in load of traffic had prompted the West Bengal Government to take drastic steps and the Pontoon Bridge was decommissioned in 1943 after being in service for 69 years. In 1937, the construction of Pontoon Bridge’s replacement has already begun. Six years later, in 1943, the Howrah Bridge – an 8-lane bridge was commissioned as a replacement of the Pontoon Bridge.
The Howrah Bridge has the capacity to bear the weight of about 1 lakh vehicles plus about 1.5 lakh pedestrians daily which it runs at full capacity - which makes it the busiest Cantilever Bridge in the world.
A Cantilever Bridge is one which is built using cantilevers based on the principles of Physics – ‘moment and shear stress’ which allows the overhanging of structures without the use of external bracing. The Howrah Bridge – a Suspension Type Balanced Cantilever was formed by riveting the whole structure which means that it doesn’t have nuts and bolts and is built using Cantilevers and Trusses (made of structural steel).
It took 26,500 tons of high-tensile alloy steel to build the Howrah Bridge. The main tower was founded with single monolith caisson (in geotechnical engineering, it is a water tight structure used to keep the working area dry under water or in muck) of dimensions 55.31 x 24.8 m with 21 shafts, each 6.25 metre square. The fabrication was done by Braithwaite, Burn & Jessop Construction Company Limited (BBJ Construction Company), Kolkata based - Government of India’s Public Sector Undertaking.
Kolkata Port Trust (founded in 1870), has been the custodian of the Howrah Bridge since its inception in 1870. It is responsible for the maintenance, repair, and refurbishment of the Howrah Bridge.
The first vehicle to use the Howrah Bridge was a Tram – which was run by a Government-based company – The Calcutta Tramways Company Limited (CTC). Incidentally, the Kolkata Tram, operating since 1902, is Asia’s oldest operating Electric Tram and was founded in 1880.