Howrah Bridge

Howrah Bridge is a propped cantilever connect with a suspended traverse over the Hooghly River in West Bengal, India. Authorized in 1943,[8][10] the scaffold was initially named the New Howrah Bridge, since it supplanted a barge connect at a similar area connecting the two urban communities of Howrah and Kolkata (Calcutta). On 14 June 1965 it was renamed Rabindra Setu after the colossal Bengali writer Rabindranath Tagore, who was the primary Indian and Asian Nobel laureate.[10] It is still prevalently known as the Howrah Bridge. 

The extension is one of four on the Hooghly River and is a celebrated image of Kolkata and West Bengal. Alternate extensions are the Vidyasagar Setu (famously called the Second Hooghly Bridge), the Vivekananda Setu, and the recently assembled Nivedita Setu. It climates the tempests of the Bay of Bengal district, conveying a day by day activity of around 100,000 vehicles[11] and potentially more than 150,000 pedestrians,[9] effectively making it the busiest cantilever connect in the world.[12] The third-longest cantilever connect at the season of its construction,[13] the Howrah Bridge is as of now the 6th longest scaffold of its sort in the world.[14]

Substance [show]

History[edit]

1862 proposition by Turnbull[edit]

In 1862, the Government of Bengal asked George Turnbull, Chief Engineer of the East India Railway Company to concentrate the attainability of spanning the Hooghly River — he had as of late settled the organization's rail end in Howrah. He gave an account of 29 March with expansive scale drawings and assessments that:[15]

The establishments for a scaffold at Calcutta would be at a significant profundity and cost on account of the profundity of the mud there.

The obstacle to transportation would be significant.

A decent place for the scaffold was at Pulta Ghat "around twelve miles north of Calcutta" where a "bed of solid earth existed at no extraordinary profundity under the waterway bed".

A suspended-support extension of five ranges of 400 feet and two ranges of 200 feet would be perfect.

The scaffold was not constructed.

Boat bridge[edit]

A photograph of the old boat connect that was later supplanted by the Howrah Bridge

In perspective of the expanding movement over the Hooghly waterway, a panel was delegated in 1855-56 to audit options for building an extension crosswise over it.[16] The arrangement was retired in 1859-60, to be restored in 1868, when it was chosen that a scaffold ought to be developed and a recently designated put stock in vested to oversee it. The Calcutta Port Trust was established in 1870,[8] and the Legislative division of the then Government of Bengal passed the Howrah Bridge Act in the year 1871 under the Bengal Act IX of 1871,[8][16] engaging the Lieutenant-Governor to have the scaffold developed with Government capital under the aegis of the Port Commissioners.

The Howrah Bridge Act of 1871

In the end an agreement was marked with Sir Bradford Leslie to develop a barge connect. Diverse parts were developed in England and sent to Calcutta, where they were collected. The collecting time frame was loaded with issues. The scaffold was extensively harmed by the considerable twister on 20 March 1874.[7] A steamer named Egeria broke from her moorings and impacted head-on with the scaffold, sinking three barges and harming about 200 feet of the bridge.[7] The extension was finished in 1874,[8] at an aggregate cost of ₹2.2 million,[16] and opened to movement on 17 October of that year.[7] The extension was then 1528 ft. long and 62 ft. wide, with 7-foot wide asphalts on either side.[8] Initially the extension was intermittently detached to enable steamers and other marine vehicles to go through. Before 1906, the scaffold used to be fixed for the entry of vessels amid daytime as it were. Since June of that year it began opening around evening time for all vessels aside from sea steamers, which were required to go through amid daytime.[16] From 19 August 1879, the extension was lit up by electric light posts, controlled by the dynamo at the Mullick Ghat Pumping Station.[8] As the scaffold couldn't deal with the quickly expanding load, the Port Commissioners began arranging in 1905 for another enhanced scaffold.

Plans for another bridge[edit]

In 1906[7] the Port Commission delegated a board of trustees headed by R.S. Highet, Chief Engineer, East Indian Railway and W.B. MacCabe, Chief Engineer, Calcutta Corporation. They presented a report expressing that[8]

Bullock trucks shaped the eight - thirteenths of the vehicular movement (as seen on 27 August 1906, the heaviest day's activity seen in the port of Commissioners 16 days' Census of the vehicular movement over the current extension). The roadway on the current scaffold is 48 feet wide aside from at the shore traverses where it is just 43 feet in roadways, every 21 feet 6 inches wide. The roadway on the new scaffold would be sufficiently wide to take no less than two lines of vehicular activity and one line of cable cars toward every path and two roadways every 30 feet wide, giving an aggregate width of 60 feet of street way which are very adequate for this purpose.................... The activity over the current gliding span Calcutta and Howrah is substantial and it is clear if the new extension is to be on an indistinguishable site from the current scaffold, then unless an impermanent scaffold is given, there will be not kidding interferences to the movement while existing extension is being moved to the other side to enable the new scaffold to be raised on an indistinguishable site from the present scaffold.

The advisory group considered six choices:

Expansive ship steamers equipped for conveying vehicular load (set up cost ₹900,000, yearly cost ₹437,000)

A transporters connect (set up cost ₹2 million)

A passage (set up cost ₹338.2 million, yearly upkeep cost ₹1779,000)

An extension on wharfs (set up cost ₹22.5 million)

A drifting scaffold (set up cost ₹2140,000, yearly upkeep cost ₹200,000)

A curved scaffold

The board of trustees in the long run chosen a gliding span. It stretched out tenders to 23 firms for its plan and development. Prize cash of £ 3,000 (₹45,000, at the then swapping scale) was announced for the firm whose outline would be accepted.[8]

Arranging and estimation[edit]

The Howrah Bridge Amendment Act, 1935

The underlying development procedure of the extension was slowed down because of the World War I, in spite of the fact that the scaffold was halfway reestablished in 1917 and 1927. In 1921 a board of architects named the 'Mukherjee Committee' was framed, headed by Sir R.N. Mukherjee, Sir Clement Hindley, Chairman of Calcutta Port Trust and J. McGlashan, Chief Engineer. They alluded the matter to Sir Basil Mott, who proposed a solitary traverse curve bridge.[8] Charles Alfred O"Grady one of the Engineers

In 1922 the New Howrah Bridge Commission was set up, to which the Mukherjee Committee presented its report. In 1926 the New Howrah Bridge Act passed. In 1930 the Goode Committee was shaped, involving S.W. Goode as President, S.N. Mallick, and W.H. Thompson, to examine and write about the suitability of developing a dock connect amongst Calcutta and Howrah. In light of their proposal, M/s. Rendel, Palmer and Tritton were solicited to consider the development from a suspension extension of a specific plan arranged by their central artist Mr. Walton.[8] On premise of the report, a worldwide delicate was glided. The most reduced offer originated from a German organization, however because of expanding political pressures amongst Germany and Great Britain in 1935, it was not given the contract.[7] The Braithwaite Burn and Jessop Construction Company Limited was granted the development get that year. The New Howrah Bridge Act was revised in 1935 to mirror this, and development of the scaffold began the following year.[8]

Construction[edit]

The extension does not have nuts and bolts,[10][17] but rather was framed by riveting the entire structure. It devoured 26,500 tons of steel, out of which 23,000 tons of high-pliable compound steel, known as Tiscrom, were provided by Tata Steel.[7][18] The primary tower was built with single stone monument caissons of measurements 55.31 x 24.8 m[4][19] with 21 shafts, each 6.25 meter square.[20] The Chief Engineer of the Port Trust, Mr. J. McGlashan, needed to supplant the barge connect, with a changeless structure, as the present scaffold meddled with North/South stream movement. Work couldn't be begun as World War I (1914-1918) broke out. At that point in 1926 a commission under the Chairmanship of Sir R. N. Mukherjee suggested a suspension scaffold of a specific sort to be worked over the River Hoogly. The scaffold was composed by one Mr.Walton of M/s Rendel, Palmer and Triton. The request for development and erection was put on M/s.Cleveland Bridge and Engineering Company in 1939. Again World War II (1939-1945 ) interceded. All the steel that was to originate from England were occupied for war exertion in Europe. Out of 26,000 tons of steel, that was required for the extension, just 3000 tons were provided from England. Regardless of the Japanese risk the then ( British ) Government of India gone ahead with the development. Goodbye Steel were made a request to supply the staying 23,000 tons of high strain steel. The Tatas built up the nature of steel required for the scaffold and called it Tiscom. The whole 23,000 tons was provided in time. The manufacture and erection work was granted to a nearby building firm of Howrah - The Braithwaite Burn and Jessop Construction Company. The two safe haven caissons were each 16.4 m by 8.2 m, with two wells 4.9 m square. The caissons were designed to the point that the working loads inside the poles could be briefly encased by steel stomachs to permit work under packed air if required.[20] The caisson at Kolkata side was set at 31.41 m and that at Howrah side at 26.53 m subterranean level.[4]

One night, amid the way toward snatching out the garbage to empower the caisson to move, the ground underneath it yielded, and the whole mass dove two feet, shaking the ground. The effect of this was intense to the point that the seismograph at Kidderpore enlisted it as a tremor and a Hindu sanctuary on the shore was obliterated, despite the fact that it was subseque