File:Howrah Bridge - Smeet Chowdhury.jpg

English: INTRODUCTION : -

The Howrah Bridge is a cantilever bridge that spans the Hooghly River in West Bengal . It was commissioned in the year 1943 . The bridge was originally named the New Howrah Bridge , because it links the city of Howrah to its twin city, Kolkata (Calcutta) . On 14 June (1965) , it was renamed Rabindra Setu , after Rabindranath Tagore , a great Bengal poet and the first Indian Nobel laureate . However it is still popularly known as the Howrah Bridge . The bridge is one of the four on the Hooghly River and is a famous symbol of Kolkata and West Bengal . Inspite of the stormy weather of the Bay of Bengal region , it successfully bears the weight of a daily traffic of approximately 100,000 vehicles and possibly more than 150,000 pedestrians , easily making it the busiest cantilever bridge in the world . The third longest cantilever bridge at the time of its construction , it is currently the sixth longest bridge of its type in the world .

HISTORY  :-

In 1862 , the Government of Bengal asked George Turnbull , Chief Engineer of the East India Railway Company to study the feasibility of bridging the Hooghly River — he had recently established the company's rail terminus in Howrah . He reported on 29 March with large-scale drawings and estimates that : - (01) The foundations for a bridge at Calcutta would be at a considerable depth and cost because of the depth of the mud there. (02) The impediment to shipping would be considerable. (03) A good place for the bridge was at Pulta Ghat "about a dozen miles north of Calcutta" where a "bed of stiff clay existed at no great depth under the river bed". (04) A suspended-girder bridge of five spans of 400 feet and two spans of 200 feet would be ideal. The bridge was not built . In face of the increasing traffic across the Hooghly river, a committee was appointed in 1855-56 to oversee the possibilities of constructing a bridge across it . A contract was signed with Sir Bradford Leslie to construct a pontoon bridge , and work commenced , the different parts being constructed in England and sent to Calcutta to be assembled together . The assembling period was fraught with problems . The bridge was considerably damaged by the great cyclone on 20 March (1874) . A steamer named Egeria broke from her moorings and collided head-on with the bridge , sinking three pontoons and damaging nearly 200 feet of the bridge . The bridge was completed in 1874 and opened to traffic on 17 October of that year . The bridge was then 1528 ft. long and 62 ft. wide , with 7 foot wide pavements on either side . Initially the bridge used to be periodically unfastened to allow steamers and other marine vehicles to pass through . Before 1906 , the bridge used to be undone for the passage of vessels during daytime only , but since June of that year it started opening at night for all vessels except ocean steamers , which were required to pass through during daytime .[ From 19 August 1879 , the bridge started being illuminated by electric lamp-posts , powered by the dynamo at the Mullick Ghat Pumping Station . However the bridge started to prove inefficient to cater to the rapidly increasing load , and the Port Commissioners started making plans for a new improved bridge in 1905 . The initial construction process of the bridge was stalled due to the World War I , although the bridge was partially renewed in 1917 and 1927 . In 1921 , a committee of engineers named the 'Mukherjee Committee' was formed , headed by Sir R.N. Mukherjee , Sir Clement Hindley , Chairman of Calcutta Port Trust and Mr. J. McGlashan , Chief Engineer . They referred the matter to Sir Basil Mott , who proposed a single span arch bridge . In 1922 , the New Howrah Bridge Commission was set up, to which the Mukherjee Committee submitted its report . In 1926 , the New Howrah Bridge Act passed . In 1930 , the Goode Committee was formed , comprising Mr. S.W. Goode as President , Mr. S.N. Mallick , and Mr. W.H. Thompson , to investigate and report on the advisability of constructing a pier bridge between Calcutta and Howrah . Based on their recommendation, M/s. Rendel, Palmer and Tritton were asked to consider the construction of a suspension bridge of a particular design prepared by their chief draftsman Mr. Walton . On basis of the report , a global tender was floated , and although the lowest bid came from a German company , due to the imminent World War II and Germany's possible participation in it , it wasn't given the contract , and instead the British firm Cleveland Bridge & Engineering Company was entrusted with the bridge construction in 1935 . The same year the New Howrah Bridge Act was amended , and construction of the bridge started the next year .

DESCRIPTION : -

When commissioned in 1943 , it was the 3rd longest cantilever bridge in the world , behind Pont de Québec (549 m) and Forth Bridge (521 m) . It has since been surpassed by three more bridges, making it currently the sixth longest cantilever bridge in the world. To be precise , it is a Suspension type Balanced Cantilever bridge , with a central span 1500 ft between centers of main towers and a suspended span of 564 ft . The main towers are 280 ft high above the monoliths and 76 ft apart at the top . The anchor arms are 325 ft each , while the cantilever arms are 468 ft each . The bridge deck hangs from panel points in the lower chord of the main trusses with 39 pairs of hangers . The roads way beyond the towers are supported from ground , leaving the anchor arms free from deck load . The deck system includes cross girders suspended between the pairs of hangers by a pinned connection . Six rows of longitudinal stringer girders are arranged between cross girders. Floor beams are supported transversally on top of the stringers , while themselves supporting a continuous pressed steel troughing system surfaced with concrete . The longitudinal expansion and lateral sway movement of the deck are taken care of by expansion and articulation joints . There are two main expansion joints , one at each interface between the suspended span and the cantilever arms , and there are others at the towers and at the interface of the steel and concrete structures at both approach . There are total 8 articulation joints , 3 at each of the cantilever arms and 1 each in the suspended portion . These joints divide the bridge into segments with vertical pin connection between them to facilitate rotational movements of the deck . The bridge deck has longitudinal ruling gradient of 1 in 40 from either end , joined by a vertical curve of radius 4000 ft . The cross gradient of deck is 1 in 48 between kerbs . The bridge serves as the gateway to Kolkata , connecting it to the Howrah Station , which is one of the four major train stations serving Howrah and Kolkata . As such , it carries the near entirety of the traffic to and from the station , taking its average daily traffic close to nearly 1.5 million pedestrians and 1 million vehicles . In 1946 , a census was taken to take a count of the daily traffic , it amounted to 27,400 vehicles , 121,100 pedestrians and 2,997 cattle . The bulk of the vehicular traffic comes from buses and cars . Prior to 1993 , the bridge used to carry trams also . Trams departed from the terminus at Howrah station towards Rajabazar , Sealdah , High Court , Dalhousie Square , Park Circus and Shyambazar . From 1993 , the tram services on the bridge were discontinued due to increasing load on the bridge. However the bridge still continues to carry much more than the expected load . Nearly 90,000 vehicles were plying on the bridge daily (15,000 of which were goods-carrying) , though its load-bearing capacity is only 60,000 . One of the main reasons of overloading was that although vehicles carrying up to 15 tonnes are allowed on the structure , vehicles with 12-18 wheels and carrying load up to 25 tonnes often plied on it . May 31 , 2007 onwards , overload trucks were banned from plying on the bridge , and were redirected to the Vidyasagar Setu instead . The road is flanked by footpaths of width 15 feet and they swarm with pedestrians .

SIGNIFICANCE : -

The bridge has become an iconic landmark and symbol of Kolkata . Rudyard Kipling mentioned the bridge in City of Dreadful Night : - " Why , this is London ! This is the docks . This is Imperial . This is worth coming across India to see ! "