A Brief History of Howrah Bridge, One of the World’s Busiest Bridges
Howrah Bridge is a balanced cantilever bridge over the Hooghly
River in West Bengal, India. Commissioned in 1943, the bridge was
originally named the New Howrah Bridge, because it replaced a pontoon bridge
at the same location linking the two cities of Howrah and Kolkata
(Calcutta). On 14 June 1965, it was renamed Rabindra Setu after
the great Bengali poet Rabindranath Tagore, who was the first
Indian and Asian Nobel laureate. It is still popularly known as the
Howrah Bridge.
The bridge is one of four on the Hooghly
River and is a famous symbol of Kolkata and West Bengal. The
other bridges are the Vidyasagar Setu (popularly called the Second
Hooghly Bridge), the Vivekananda Setu, and the newly built Nivedita
Setu. It carries 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, the Howrah Bridge is currently the sixth-longest bridge of its
type in the world. On your visit to Kolkata, this is one attraction that you
must definitely not avoid visiting. It is no less than a magical wonder that
the bridge stands with such grandeur.
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| Vidyasagar Setu |
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| Vivekananda Setu |
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| Nivedita Setu |
History
1862
proposal by Turnbull
In 1862, the Government of Bengal asked George Turnbull, chief engineer of the East Indian 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 19 March, with large-scale drawings and estimates, that:
1. The foundations for a bridge at
Calcutta would be at a considerable depth and cost because of the depth of the
mud there.
2. The impediment to shipping would be
considerable.
3. 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".
4. A suspended-girder bridge of five
spans of 401 feet (122 m) and two spans 200 feet (61 m) would be
ideal.
Pontoon Bridge
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The old Pontoon bridge, which was later replaced by the Howrah Bridge Because of the increasing traffic across the Hooghly River, a committee was appointed in 1855-56 to review alternatives for constructing a bridge across it. The plan was shelved in 1859-60, to be revived in 1868, when it was decided that a bridge should be constructed and a newly appointed trust vested to manage it. The Calcutta Port Trust was founded in 1870, and the legislative department of the then Government of Bengal passed the Howrah Bridge Act in the year 1871 under the Bengal Act IX of 1871, empowering the lieutenant-governor to have the bridge constructed with Government capital under the aegis of the Port Commissioners. |
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The
Howrah Bridge Act of 1871 Eventually, a contract was signed with Sir Bradford Leslie to construct a Pontoon Bridge. Different parts were constructed in England and shipped to Calcutta, where they were assembled. But there was a problem in the assembling period, as 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 complete in 1874, at a total cost of ₹ 2.2 million, 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 was 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 the daytime only. Since June of that year, it started opening at night for all vessels except ocean steamers, which were required to pass through during the daytime. From 19 August 1879, the bridge was illuminated by electric lamp-posts, powered by the dynamo at the Mullick Ghat Pumping Station. As the bridge could not handle the rapidly increasing load, the Port Commissioners started planning in 1905 for a new improved bridge. Plans
for a new bridgeIn 1906 the Port Commission appointed a committee headed by R.S. Highet, chief engineer, East Indian Railway, and W.B. MacCabe, chief engineer, Calcutta Corporation. They submitted a report stating that: Bullock carts formed the eight - thirteenths of the vehicular traffic (as
observed on 27 August 1906, the heaviest day's traffic observed in the port of
Commissioners 16 days' Census of the vehicular traffic across the existing
bridge). The roadway on the existing bridge is 48 feet wide except at the shore
spans where it is only 43 feet in roadways, each 21 feet 6 inches wide. The roadway on the new bridge would be wide enough to take at least two lines of
vehicular traffic and one line of trams in each direction and two roadways each
30 feet wide, giving a total width of 60 feet of roadway which are quite
sufficient for this purpose [...] The traffic across the existing floating bridge Calcutta & Howrah is very
heavy and it is obvious if the new bridge is to be on the same site as the existing bridge, then unless a temporary bridge is provided, there will be
serious interruptions to the traffic while the existing bridge is being moved to
one side to allow the new bridge to be erected on the same site as the present
bridge. The committee considered six options:
The committee eventually decided on a floating bridge. It extended tenders to 23 firms for its design and construction. Prize money of £ 3,000 (₹ 45,000, at the then exchange rate) was declared for the firm whose design would be accepted.
Planning
and estimation The
Howrah Bridge Amendment Act, 1935 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 R. N. Mukherji, Sir Clement Hindley, chairman of Calcutta Port Trust and 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. In 1926 the New Howrah Bridge Act passed. In 1930 the Goode Committee was formed, comprising S.W. Goode as president, S.N. Mallick, and 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. The lowest bid came from a German company, but due to increasing political tensions between Germany and Great Britain in 1935, it was not given the contract. The Braithwaite, Burn & Jessop Construction Co. was awarded the construction contract that year. The New Howrah Bridge Act was amended in 1935 to reflect this, and construction of the bridge started the next year. |
Construction
The bridge does not have nuts and bolts but was formed by riveting the whole structure. It consumed 26,500 tons of steel, out of which 23,000 tons of high-tensile alloy steel, known as Tiscrom, were supplied by Tata Steel. The main tower was constructed with single monolith caissons of dimensions 55.31 x 24.8 m with 21 shafts, each 6.25-meter square. The Chief Engineer of the Port Trust, Mr. J. McGlashan, wanted to replace the pontoon bridge, with a permanent structure, as the present bridge interfered with North/South river traffic. Work could not be started as World War I (1914–1918) broke out. Then in 1926 a commission under the chairmanship of Sir R. N. Mukherjee recommended a suspension bridge of a particular type to be built across the River Hooghly. The bridge was designed by one Mr. Walton of M/s Rendel, Palmer & Triton. The order for construction and erection was placed on M/s.Cleveland Bridge & Engineering Company in 1939. Again World War II (1939–1945) intervened. All the steel that was to come from England was diverted for the war effort in Europe. Out of 26,000 tons of steel, required for the bridge, only 3000 tons were supplied from England. Despite the Japanese threat, the then (British) government of India pressed on with the construction. Tata Steel was asked to supply the remaining 23,000 tons of high-tension steel. The Tata’s developed the quality of steel required for the bridge and called it Tiscrom. The entire 23,000 tons was supplied in time. The fabrication and erection work was awarded to a local engineering firm of Howrah: the Braithwaite, Burn & Jessop Construction Co. The two anchorage caissons were each 16.4 m by 8.2 m, with two wells 4.9 m square. The caissons were so designed that the working chambers within the shafts could be temporarily enclosed by steel diaphragms to allow work under compressed air if required. The caisson at Kolkata side was set at 31.41 m and that at Howrah side at 26.53 m below ground level.
One night, during the process of grabbing out the muck to enable the caisson to move, the ground below it yielded, and the entire mass plunged two feet, shaking the ground. The impact of this was so intense that the seismograph at Kidderpore registered it as an earthquake and a Hindu temple on the shore was destroyed, although it was subsequently rebuilt. While muck was being cleared, numerous varieties of objects were brought up, including anchors, grappling irons, cannons, cannonballs, brass vessels, and coins dating back to the East India Company. The job of sinking the caissons was carried out round-the-clock at a rate of a foot or more per day. The caissons were sunk through soft river deposits to stiff yellow clay 26.5 m below ground level. The accuracy of sinking the huge caissons was exceptionally precise, within 50–75 mm of the true position. After penetrating 2.1 m into clay, all shafts were plugged with concrete after individual dewatering, with some 5 m of backfilling in adjacent shafts. The main piers on the Howrah side were sunk by open-wheel dredging, while those on the Kolkata side required compressed air to counter running sand. The air pressure maintained was about 40 lbs per square inch (2.8 bar), which required about 500 workers to be employed. Whenever excessively soft soil was encountered, the shafts symmetrical to the caisson axes were left unexcavated to allow strict control. In very stiff clays, many internal wells were completely undercut, allowing the whole weight of the caisson to be carried by the outside skin friction and the bearing under the external wall. Skin friction on the outside of the monolith walls was estimated at 29 kN/m2 while loads on the cutting edge in clay overlying the founding stratum reached 100 tonnes/m. The work on the foundation was completed in November 1938.
By the end of 1940, the erection of the cantilevered arms was commenced and was completed in mid-summer of 1941. The two halves of the suspended span, each 282 feet (86 m) long and weighing 2,000 tons were built in December 1941. The bridge was erected by commencing at the two anchor spans and advancing towards the center, with the use of creeper cranes moving along the upper chord. 16 hydraulic jacks, each of which had an 800-ton capacity, were pressed into service to join the two halves of the suspended span.
The entire project cost ₹25 million (£2,463,887). The project was a pioneer in bridge construction, particularly in India, but the government did not have a formal opening of the bridge due to fears of attacks by Japanese planes fighting the Allied Powers. Japan had attacked the United States at Pearl Harbor on December 7, 1941. The first vehicle to use the bridge was a solitary tram.
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| Elevation of Howrah bridge |
The bridge is regarded as "The Gateway to Kolkata, as it connects the city to Howrah Station".
Description
Specifications
When commissioned in 1943, Howrah was the 3rd-longest cantilever bridge in the world, behind Pont de Québec (549 meters (1,801 ft)) in Canada and Forth Bridge (521 meters (1,709 ft)) in Scotland. It has since been surpassed by three bridges, making it the sixth-longest cantilever bridge in the world in 2013. It is a suspension-type balanced cantilever bridge, with a central span of 1,500 feet (460 m) between centers of main towers and a suspended span of 564 feet (172 m). The main towers are 280 feet (85 m) high above the monoliths and 76 feet (23 m) apart at the top. The anchor arms are 325 feet (99 m) each, while the cantilever arms are 468 feet (143 m) each. The bridge deck hangs from panel points in the lower chord of the main trusses with 39 pairs of hangers. The roadways beyond the towers are supported from the 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 those supporting a continuous pressed steel troughing system surfaced with concrete.
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| Howrah Bridge, 1945 |
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 approaches. 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 connections between them to facilitate rotational movements of the deck. The bridge deck has a longitudinal ruling gradient of 1 in 40 from either end, joined by a vertical curve of a radius of 4,000 feet (1,200 m). The cross gradient of the deck is 1 in 48 between curbs.
Traffic
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Bridge Traffic |
The bridge serves as the gateway to Kolkata, connecting it to the Howrah Station, which is one of the five intercity train terminus 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 150,000 pedestrians and 100,000 vehicles. In 1946, a census of the daily traffic was taken, which counted 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 also carried trams. Trams departed from the terminus at Howrah station towards Sealdah, Rajabazar, Shyambazar, High Court, Dalhousie Square, Park Circus, Ballygunge, Tollygunge, etc. In 1993, tram service on the bridge was discontinued due to the increased load on the structure. However, the bridge still continues to carry much more than the expected load. A 2007 report revealed that nearly 90,000 vehicles were playing 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 for the overloading was that, although vehicles carrying up to 15 tonnes are allowed on the structure, vehicles with 12-18 wheels and carrying loads up to 25 tonnes often plied on it. From 31 May 2007 onwards, overloaded trucks were banned from crossing the bridge and were redirected to the Vidyasagar Setu instead. The road is flanked by footpaths 15 feet (4.6 m) wide, which are thronged with pedestrians.
Traffic Flow for fast moving heavy vehicles
Year
Trams
Buses/Vans
Trucks
1959
13%
41%
46%
1986
4%
80%
16%
1990
3%
82%
15%
1992
2%
80%
18%
1999
-
89%
11%
Traffic Flow for fast-moving light vehicles
Year
Two-wheelers/Autos
Cars/Taxis
1959
2.47%
97.53%
1986
24%
76%
1990
27%
73%
1992
26%
74%
1999
20%
80%
Maintenance
The Kolkata Port Trust (KoPT) is vested with the maintenance of the bridge. The bridge has been subject to damage from vehicles due to rash driving, and corrosion due to atmospheric conditions and biological wastes. On October 2008, 6 high-tech surveillance cameras were placed to monitor the entire 705 meters (2,313 ft) long and 30 meters (98 ft) wide structure from the control room. Two of the cameras were placed under the floor of the bridge to track the movement of barges, steamers, and boats on the river, while the other four were fixed to the first layer of beams — one at each end and two in the middle — to monitor vehicle movements. This was in response to substantial damage caused to the bridge from collisions with vehicles, so that compensation could be claimed from the miscreants.
| The illuminated Howrah Bridge at night |
Corrosion has been caused by bird droppings and human spitting. An investigation in 2003 revealed that as a result of prolonged chemical reaction caused by continuous collection of bird excreta, several joints and parts of the bridge were damaged. As an immediate measure, the Kolkata Port Trust engaged contractors to regularly clean the bird droppings, at an annual expense of ₹500,000 (US$7,000). In 2004, KoPT spent ₹6.5 million (US$91,000) to paint the entirety of 2.2 million square meters (24 million square feet) of the bridge. Two coats of aluminium paint, with a primer of zinc chromate before that, was applied on the bridge, requiring a total of 26,500 liters of paint.
The bridge is also considerably damaged by pedestrians spitting out acidic, lime-mixed stimulants (gutka and paan). A technical inspection by Port Trust officials in 2011 revealed that spitting had reduced the thickness of the steel hoods protecting the pillars from six to less than three millimeters since 2007. The hangers need those hoods at the base to prevent water seeping into the junction of the cross-girders and hangers, and damage to the hoods can jeopardize the safety of the bridge. KoPT announced that it will spend ₹2 million (US$28,000) on covering the base of the steel pillars with fiberglass casing to prevent spit from corroding them.
On 24 June 2005, a private cargo vessel M V Mani, belonging to the Ganges Water Transport Pvt. Ltd, while trying to pass under the bridge during high tide, had its funnel stuck underneath for three hours, causing substantial damage worth about ₹15 million to the stringer and longitudinal girder of the bridge. Some of the 40 cross-girders were also broken. Two of four trolley guides, bolted and welded with the girders, were extensively damaged. Nearly 350 meters (1,150 ft) of 700 meters (2,300 ft) of the track were twisted beyond repair. The damage was so severe that KoPT requested help from Rendall-Palmer & Tritton Limited, the original consultant on the bridge from UK. KoPT also contacted SAIL for 'matching steel' used during its construction in 1943. For the repair, which cost around ₹5 million (US$70,000), about 8 tonnes of steel was used. The repairs were completed in early 2006.
Cultural
significance
Here we summarize some facts about Howrah Bridge from the above text:
1. How it began
Before the Howrah
Bridge was born there was a proposal to build a suspended-girder bridge at the
site to cross the Hooghly River. There were also proposals to build a tunnel or
an arched bridge. As fate would have it, these plans for construction never
came to fruition.
2. Origins of Howrah Bridge
Although the construction
of the Howrah Bridge only started in the 20th century, the origins of the
structure can be traced back to 1871. This was when the Government of Bengal
took the first decisive steps to construct a permanent crossing, with the
passage of the Howrah Bridge Act. The act was amended in 1935 to facilitate
construction of the new structure.
3. Early Incarnation
Prior to the
construction of the architectural marvel that we are familiar with today, a
pontoon bridge stood, or rather, floated at the site. This was the first
incarnation of the Howrah Bridge. Off course, this type of crossing has a
limited load carrying capacity, so it was eventually replaced.
4. World War II Impact
Howrah Bridge may have
looked quite different if not for World War II hostilities. Bidding for a
global tender was to be awarded to the lowest bidder, which was a German
company. Increased hostilities in 1935 resulted in cancellation of the
contract, which was instead awarded to India’s Braithwaite Burn & Jessop
Construction Company Limited.
5. Building the Bridge
Construction of Howrah
Bridge took 6 years, starting in 1936. The architects used a cantilever
suspension design, in which large beams are supported at one end, while
projecting horizontally at the other. The bridge was finally opened to the
public a year after its completion, in 1943.
6. The First Crossing
The first transport to
make the journey across the Hooghly, via the newly opened bridge was not a car
or a bullock cart; it was a tram. Because of the heavy load on the bridge the
use of trams was discontinued along the route from 1993.
7. It’s on a Top 10 List
The Howrah Bridge
stretches across 705 meters and has a width of 71 feet, not including the 14
feet footpaths on both sides. At the time of its construction this made it the
3rd longest bridge of its kind. Today, it is regarded as the 6th longest
cantilever bridge in the world.
8. A Forgotten Tribute?
Our government leaders
are known for their zeal of renaming cities and monuments and although done
with the best of intentions, sometimes these endeavors are just misguided. In
honor of the first Asian Nobel Laureate, Rabindranath Tagore, the bridge was
rechristened as Rabindra Setu in 1965. Although Bengalis are immensely proud of
their heritage and cherish their memories of Tagore, Howrah Bridge is simply a
lot more convenient as a name; 50 years later it still goes by this name.
9. The Tata Legacy
Tata Steel is very much
a part of India’s heritage and history, being at the forefront of India’s
industrial revolution, since its birth over 100 years ago. The history of
Howrah Bridge is also a part of the Tata legacy, as it supplied 23,000 tons of
steel for the project. What’s interesting is that there are no nuts and bolts
in the structure, as the builders used steel riveting instead.
10. Record Breaking Traffic
The Howrah Bridge may
be the world’s busiest cantilever bridge, bearing a load of around 100,000
vehicles and over 150,000 pedestrians each day. To put those figures in
perspective, traffic in 1946 was recorded as little over 27,000 vehicles,
around 121,000 pedestrians, and close to 3,000 cattle.
11. Inauguration and the Initial Years
The first vehicle to
cross over the Howrah Bridge was a tram. At that time traffic came from
two-wheelers, cars, buses, trams and trucks plying on the bridge. A 1946 census
revealed that over 27,400 vehicles, 121,100 pedestrians and 2,997 cattle
crossed over the Howrah Bridge daily. The number has only grown over the years.
2007 reports put the number of vehicles at almost 90,000.In 1993, trams were
stopped from using the bridge, and the route was discontinued. The reason
behind this was that the bridge would not be able to take the heavy load of
trams in light of increased traffic and footfalls.
12. The Howrah Bridge Today
Tram on Howrah bridge
The Howrah Bridge today
is a proud symbol of Kolkata. It is often called the gateway to Kolkata and
with good reason, as it connects the city with the Howrah Railway Junction. At
the other end of the bridge is the colorful chaos of the Mullick Ghat Flower
Market. Today, with nearly 100,000 vehicles and over 150,000 pedestrians
passing by daily the Howrah Bridge is perhaps the busiest cantilever bridge in
the world.
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Important
Notes |
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Coordinates |
22.5851°N
88.3469°E |
|
Carries |
4
lanes of Strand Road, pedestrians, and bicycles |
|
Crosses |
Hooghly
River |
|
Locale |
Howrah
and Kolkata |
|
Official
name |
Rabindra
Setu |
|
Maintained
by |
Kolkata
Port Trust |
|
Characteristics |
|
|
Design |
Suspension
type Balanced Cantilever and truss arch |
|
Material |
Steel |
|
Total
length |
705 m
(2,313.0 ft) |
|
Width |
71 ft
(21.6 m) with two footpaths of 15 ft (4.6 m) on either side |
|
Height |
82 m
(269.0 ft) |
|
Longest
span |
1,500 ft
(457.2 m) |
|
Clearance
above |
5.8 m
(19.0 ft) |
|
Clearance
below |
8.8 m
(28.9 ft) |
|
History |
|
|
Designer |
Amit
Kumar, Gaurav (engineer), and Tritton |
|
Constructed
by |
Braithwaite,
Burn & Jessop Construction Company |
|
Construction
start |
1936 |
|
Construction
end |
1942 |
|
Opened |
3
February 1943; 78 years ago |
|
Statistics |
|
|
Daily
traffic |
300,000
vehicles and 450,000 pedestrians |
|
Toll |
Toll-Free
on both ways |
How many of these were you aware of?
Did we miss out on anything?
Let us know in the comments section below.
Published by Dazzling
Kolkata
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