122-589: The Howrah Bridge is a balanced steel 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 twin cities of Howrah and Kolkata , which are located at the opposite banks of each other. On 14 June 1965, it was renamed Rabindra Setu after
244-412: A BOS process is manufactured in one-twelfth the time. Today, electric arc furnaces (EAF) are a common method of reprocessing scrap metal to create new steel. They can also be used for converting pig iron to steel, but they use a lot of electrical energy (about 440 kWh per metric ton), and are thus generally only economical when there is a plentiful supply of cheap electricity. The steel industry
366-713: A carbon-intermediate steel by the 1st century AD. There is evidence that carbon steel was made in Western Tanzania by the ancestors of the Haya people as early as 2,000 years ago by a complex process of "pre-heating" allowing temperatures inside a furnace to reach 1300 to 1400 °C. Evidence of the earliest production of high carbon steel in South Asia is found in Kodumanal in Tamil Nadu ,
488-444: A change of volume. In this case, expansion occurs. Internal stresses from this expansion generally take the form of compression on the crystals of martensite and tension on the remaining ferrite, with a fair amount of shear on both constituents. If quenching is done improperly, the internal stresses can cause a part to shatter as it cools. At the very least, they cause internal work hardening and other microscopic imperfections. It
610-522: A commission under the chairmanship of Sir R. N. Mukherjee recommended a suspension bridge of a particular type to be built across the River Hoogly. 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
732-512: A contract was signed with Sir Bradford Leslie to construct a pontoon bridge . Different parts of the bridge were constructed in England and shipped to Calcutta, where they were assembled. 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
854-631: 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. In 1862, the Government of Bengal asked George Turnbull , chief engineer of the East Indian Railway Company to study
976-428: A ferrite BCC crystal form, but at higher carbon content it takes a body-centred tetragonal (BCT) structure. There is no thermal activation energy for the transformation from austenite to martensite. There is no compositional change so the atoms generally retain their same neighbours. Martensite has a lower density (it expands during the cooling) than does austenite, so that the transformation between them results in
1098-445: A hard but brittle martensitic structure. The steel is then tempered, which is just a specialized type of annealing, to reduce brittleness. In this application the annealing (tempering) process transforms some of the martensite into cementite, or spheroidite and hence it reduces the internal stresses and defects. The result is a more ductile and fracture-resistant steel. When iron is smelted from its ore, it contains more carbon than
1220-520: A local currency that is pegged to the U.S. dollar or the New Zealand dollar . The Sovereign Base Areas of Akrotiri and Dhekelia (in Cyprus ) use the euro. Since decimalisation on Decimal Day in 1971, the pound has been divided into 100 pence (denoted on coinage, until 1981, as "new pence"). The symbol for the penny is "p"; hence an amount such as 50p (£0.50) properly pronounced "fifty pence"
1342-412: A narrow range of concentrations of mixtures of carbon and iron that make steel, several different metallurgical structures, with very different properties can form. Understanding such properties is essential to making quality steel. At room temperature , the most stable form of pure iron is the body-centred cubic (BCC) structure called alpha iron or α-iron. It is a fairly soft metal that can dissolve only
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#17327723320931464-399: A penny", "two and a penny", etc. 5 shillings, for example, was written as "5 s ." or, more commonly, "5/–" (five shillings, no pence). Various coin denominations had, and in some cases continue to have, special names, such as florin (2/–), crown (5/–), half crown (2/6 d ), farthing ( 1 ⁄ 4 d ), sovereign (£1) and guinea (21s, 21/–, £1–1–0 or £1.05 in decimal notation). By
1586-422: 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
1708-484: 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
1830-418: 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
1952-534: A small concentration of carbon, no more than 0.005% at 0 °C (32 °F) and 0.021 wt% at 723 °C (1,333 °F). The inclusion of carbon in alpha iron is called ferrite . At 910 °C, pure iron transforms into a face-centred cubic (FCC) structure, called gamma iron or γ-iron. The inclusion of carbon in gamma iron is called austenite. The more open FCC structure of austenite can dissolve considerably more carbon, as much as 2.1%, (38 times that of ferrite) carbon at 1,148 °C (2,098 °F), which reflects
2074-453: A steel's final rolling, it is heat treated for strength; however, this is relatively rare. Steel was known in antiquity and was produced in bloomeries and crucibles . The earliest known production of steel is seen in pieces of ironware excavated from an archaeological site in Anatolia ( Kaman-Kalehöyük ) which are nearly 4,000 years old, dating from 1800 BC. Wootz steel
2196-428: 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 ground, leaving
2318-672: Is continuously cast into long slabs, cut and shaped into bars and extrusions and heat treated to produce a final product. Today, approximately 96% of steel is continuously cast, while only 4% is produced as ingots. The ingots are then heated in a soaking pit and hot rolled into slabs, billets , or blooms . Slabs are hot or cold rolled into sheet metal or plates. Billets are hot or cold rolled into bars, rods, and wire. Blooms are hot or cold rolled into structural steel , such as I-beams and rails . In modern steel mills these processes often occur in one assembly line , with ore coming in and finished steel products coming out. Sometimes after
2440-403: Is common for quench cracks to form when steel is water quenched, although they may not always be visible. There are many types of heat treating processes available to steel. The most common are annealing , quenching , and tempering . Annealing is the process of heating the steel to a sufficiently high temperature to relieve local internal stresses. It does not create a general softening of
2562-403: Is desirable. To become steel, it must be reprocessed to reduce the carbon to the correct amount, at which point other elements can be added. In the past, steel facilities would cast the raw steel product into ingots which would be stored until use in further refinement processes that resulted in the finished product. In modern facilities, the initial product is close to the final composition and
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#17327723320932684-453: Is distinguishable from wrought iron (now largely obsolete), which may contain a small amount of carbon but large amounts of slag . Iron is commonly found in the Earth's crust in the form of an ore , usually an iron oxide, such as magnetite or hematite . Iron is extracted from iron ore by removing the oxygen through its combination with a preferred chemical partner such as carbon which
2806-408: Is heat treated to contain both a ferritic and martensitic microstructure to produce a formable, high strength steel. Transformation Induced Plasticity (TRIP) steel involves special alloying and heat treatments to stabilize amounts of austenite at room temperature in normally austenite-free low-alloy ferritic steels. By applying strain, the austenite undergoes a phase transition to martensite without
2928-535: Is known as stainless steel . Tungsten slows the formation of cementite , keeping carbon in the iron matrix and allowing martensite to preferentially form at slower quench rates, resulting in high-speed steel . The addition of lead and sulphur decrease grain size, thereby making the steel easier to turn , but also more brittle and prone to corrosion. Such alloys are nevertheless frequently used for components such as nuts, bolts, and washers in applications where toughness and corrosion resistance are not paramount. For
3050-691: Is often considered an indicator of economic progress, because of the critical role played by steel in infrastructural and overall economic development . In 1980, there were more than 500,000 U.S. steelworkers. By 2000, the number of steelworkers had fallen to 224,000. The economic boom in China and India caused a massive increase in the demand for steel. Between 2000 and 2005, world steel demand increased by 6%. Since 2000, several Indian and Chinese steel firms have expanded to meet demand, such as Tata Steel (which bought Corus Group in 2007), Baosteel Group and Shagang Group . As of 2017 , though, ArcelorMittal
3172-417: Is often pronounced "fifty pee" /fɪfti piː/. The old sign d was not reused for the new penny in order to avoid confusion between the two units. A decimal halfpenny ( 1 / 2 p, worth 1.2 old pennies) was issued until 1984 but was withdrawn due to inflation . Before decimalisation in 1971 , the pound was divided into 20 shillings , and each shilling into 12 pence , making 240 pence to
3294-445: 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,
3416-514: Is one of the largest manufacturing industries in the world, but also one of the most energy and greenhouse gas emission intense industries, contributing 8% of global emissions. However, steel is also very reusable: it is one of the world's most-recycled materials, with a recycling rate of over 60% globally . The noun steel originates from the Proto-Germanic adjective * * stahliją or * * stakhlijan 'made of steel', which
3538-463: Is one of the most commonly manufactured materials in the world. Steel is used in buildings, as concrete reinforcing rods, in bridges, infrastructure, tools, ships, trains, cars, bicycles, machines, electrical appliances, furniture, and weapons. Iron is always the main element in steel, but many other elements may be present or added. Stainless steels , which are resistant to corrosion and oxidation , typically need an additional 11% chromium . Iron
3660-551: Is one of the world's most-recycled materials, with a recycling rate of over 60% globally; in the United States alone, over 82,000,000 metric tons (81,000,000 long tons; 90,000,000 short tons) were recycled in the year 2008, for an overall recycling rate of 83%. As more steel is produced than is scrapped, the amount of recycled raw materials is about 40% of the total of steel produced - in 2016, 1,628,000,000 tonnes (1.602 × 10 long tons; 1.795 × 10 short tons) of crude steel
3782-520: Is possible only by reducing iron's ductility. Steel was produced in bloomery furnaces for thousands of years, but its large-scale, industrial use began only after more efficient production methods were devised in the 17th century, with the introduction of the blast furnace and production of crucible steel . This was followed by the Bessemer process in England in the mid-19th century, and then by
Howrah Bridge - Misplaced Pages Continue
3904-434: Is possible to make very high-carbon (and other alloy material) steels, but such are not common. Cast iron is not malleable even when hot, but it can be formed by casting as it has a lower melting point than steel and good castability properties. Certain compositions of cast iron, while retaining the economies of melting and casting, can be heat treated after casting to make malleable iron or ductile iron objects. Steel
4026-400: Is quite ductile , or soft and easily formed. In steel, small amounts of carbon, other elements, and inclusions within the iron act as hardening agents that prevent the movement of dislocations . The carbon in typical steel alloys may contribute up to 2.14% of its weight. Varying the amount of carbon and many other alloying elements, as well as controlling their chemical and physical makeup in
4148-457: Is related to * * stahlaz or * * stahliją 'standing firm'. The carbon content of steel is between 0.02% and 2.14% by weight for plain carbon steel ( iron - carbon alloys ). Too little carbon content leaves (pure) iron quite soft, ductile, and weak. Carbon contents higher than those of steel make a brittle alloy commonly called pig iron . Alloy steel is steel to which other alloying elements have been intentionally added to modify
4270-615: Is the central bank for sterling, issuing its own banknotes and regulating issuance of banknotes by private banks in Scotland and Northern Ireland. Sterling banknotes issued by other jurisdictions are not regulated by the Bank of England; their governments guarantee convertibility at par . Historically, sterling was also used to varying degrees by the colonies and territories of the British Empire . There are various theories regarding
4392-578: Is the currency of the United Kingdom and nine of its associated territories. The pound ( sign: £ ) is the main unit of sterling, and the word pound is also used to refer to the British currency generally, often qualified in international contexts as the British pound or the pound sterling . Sterling is the world's oldest currency in continuous use since its inception. In 2022, it
4514-441: Is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic . The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron
4636-547: Is the world's largest steel producer . In 2005, the British Geological Survey stated China was the top steel producer with about one-third of the world share; Japan , Russia , and the United States were second, third, and fourth, respectively, according to the survey. The large production capacity of steel results also in a significant amount of carbon dioxide emissions inherent related to
4758-498: Is then lost to the atmosphere as carbon dioxide. This process, known as smelting , was first applied to metals with lower melting points, such as tin , which melts at about 250 °C (482 °F), and copper , which melts at about 1,100 °C (2,010 °F), and the combination, bronze, which has a melting point lower than 1,083 °C (1,981 °F). In comparison, cast iron melts at about 1,375 °C (2,507 °F). Small quantities of iron were smelted in ancient times, in
4880-671: The 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 relatively new Nivedita Setu . It carries
5002-655: The Golconda area in Andhra Pradesh and Karnataka , regions of India , as well as in Samanalawewa and Dehigaha Alakanda, regions of Sri Lanka . This came to be known as wootz steel , produced in South India by about the sixth century BC and exported globally. The steel technology existed prior to 326 BC in the region as they are mentioned in literature of Sangam Tamil , Arabic, and Latin as
Howrah Bridge - Misplaced Pages Continue
5124-420: The Vidyasagar Setu instead. The road is flanked by footpaths 15 feet (4.6 m) wide, which are thronged with pedestrians. 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. In October 2008, 6 high-tech surveillance cameras were placed to monitor
5246-460: The bearing under the external wall. Skin friction on the outside of the monolith walls was estimated at 29 kN/m 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
5368-599: The cementation process was described in a treatise published in Prague in 1574 and was in use in Nuremberg from 1601. A similar process for case hardening armour and files was described in a book published in Naples in 1589. The process was introduced to England in about 1614 and used to produce such steel by Sir Basil Brooke at Coalbrookdale during the 1610s. The raw material for this process were bars of iron. During
5490-607: The open-hearth furnace . With the invention of the Bessemer process, a new era of mass-produced steel began. Mild steel replaced wrought iron . The German states were the major steel producers in Europe in the 19th century. American steel production was centred in Pittsburgh , Bethlehem, Pennsylvania , and Cleveland until the late 20th century. Currently, world steel production is centered in China, which produced 54% of
5612-445: The 17th century, it was realized that the best steel came from oregrounds iron of a region north of Stockholm , Sweden. This was still the usual raw material source in the 19th century, almost as long as the process was used. Crucible steel is steel that has been melted in a crucible rather than having been forged , with the result that it is more homogeneous. Most previous furnaces could not reach high enough temperatures to melt
5734-475: The 17th century, the first step in European steel production has been the smelting of iron ore into pig iron in a blast furnace . Originally employing charcoal, modern methods use coke , which has proven more economical. In these processes, pig iron made from raw iron ore was refined (fined) in a finery forge to produce bar iron , which was then used in steel-making. The production of steel by
5856-657: The 1950s, coins of Kings George III , George IV and William IV had disappeared from circulation, but coins (at least the penny) bearing the head of every British monarch from Queen Victoria onwards could be found in circulation. Silver coins were replaced by those in cupro-nickel in 1947, and by the 1960s the silver coins were rarely seen. Silver/cupro-nickel sixpences, shillings (from any period after 1816) and florins (2 shillings) remained legal tender after decimalisation (as 2½p, 5p and 10p respectively) until 1980, 1990 and 1993 respectively, but are now officially demonetised. The pound sterling emerged after
5978-625: The 2015 YRF release from director Dibakar Banerjee 's Detective Byomkesh Bakshy! . Shoojit sircar 's " Piku " also features some scenes on this iconic bridge. The bridge was also featured in Garth Davis ' Academy Award-nominated 2016 film Lion . Anvita Dutt 's 2022 movie Qala (film) features some fictional scenes of Howrah Bridge's construction. Steel Steel is an alloy of iron and carbon with improved strength and fracture resistance compared to other forms of iron. Because of its high tensile strength and low cost, steel
6100-608: The Arabs from Persia, who took it from India. It was originally created from several different materials including various trace elements , apparently ultimately from the writings of Zosimos of Panopolis . In 327 BC, Alexander the Great was rewarded by the defeated King Porus , not with gold or silver but with 30 pounds of steel. A recent study has speculated that carbon nanotubes were included in its structure, which might explain some of its legendary qualities, though, given
6222-469: The Bank of England has exclusively used the single bar variant since 1975. Historically, a simple capital L (in the historic black-letter typeface, L {\displaystyle {\mathfrak {L}}} ) placed before the numerals, or an italic l. after them, was used in newspapers, books and letters. The Royal Mint was still using this style of notation as late as 1939. The glyphs Ł and Ⱡ may occasionally be encountered. Use of
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#17327723320936344-457: The League's money was not frequently debased like that of England, English traders stipulated to be paid in pounds of the "Easterlings", which was contracted to "'sterling". The OED dismisses this theory as unlikely, since the stressed first syllable would not have been elided. Encyclopædia Britannica states that the (pre-Norman) Anglo-Saxon kingdoms had silver coins called sterlings and that
6466-470: The Linz-Donawitz process of basic oxygen steelmaking (BOS), developed in 1952, and other oxygen steel making methods. Basic oxygen steelmaking is superior to previous steelmaking methods because the oxygen pumped into the furnace limited impurities, primarily nitrogen, that previously had entered from the air used, and because, with respect to the open hearth process, the same quantity of steel from
6588-505: The Roman libra , solidus , and denarius . Notable style guides recommend that the pound sign be used without any abbreviation or qualification to indicate sterling (e.g., £12,000). The ISO 4217 code "GBP" (e.g., GBP 12,000) may also be seen should disambiguation become necessary. The ISO 4217 currency code for sterling is "GBP", formed from the ISO 3166-1 alpha-2 code for
6710-659: The United Kingdom ("GB") and the first letter of "pound". In historical sources and some specialist banking uses, the abbreviation stg (in various styles) has been used to indicate sterling. Many stocks on the London Stock Exchange are quoted in penny sterling, using the unofficial code "GBX". The exchange rate of sterling against the US dollar is referred to as "cable" in the wholesale foreign exchange markets . The origins of this term are attributed to
6832-678: The addition of heat. Twinning Induced Plasticity (TWIP) steel uses a specific type of strain to increase the effectiveness of work hardening on the alloy. Pound sterling King Charles III [REDACTED] William, Prince of Wales [REDACTED] Charles III ( King-in-Council ) [REDACTED] Starmer ministry ( L ) Keir Starmer ( L ) Angela Rayner ( L ) ( King-in-Parliament ) [REDACTED] Charles III [REDACTED] [REDACTED] [REDACTED] The Lord Reed The Lord Hodge Andrew Bailey Monetary Policy Committee Sterling ( ISO code : GBP )
6954-546: The adoption of the Carolingian monetary system in England c. 800 . Here is a summary of changes to its value in terms of silver or gold until 1816. The pound was a unit of account in Anglo-Saxon England . By the ninth century it was equal to 240 silver pence . The accounting system of dividing one pound into twenty shillings , a shilling into twelve pence, and a penny into four farthings
7076-437: 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
7198-436: The austenite grain boundaries until the percentage of carbon in the grains has decreased to the eutectoid composition (0.8% carbon), at which point the pearlite structure forms. For steels that have less than 0.8% carbon (hypoeutectoid), ferrite will first form within the grains until the remaining composition rises to 0.8% of carbon, at which point the pearlite structure will form. No large inclusions of cementite will form at
7320-471: The austenite is for it to precipitate out of solution as cementite , leaving behind a surrounding phase of BCC iron called ferrite with a small percentage of carbon in solution. The two, cementite and ferrite, precipitate simultaneously producing a layered structure called pearlite , named for its resemblance to mother of pearl . In a hypereutectoid composition (greater than 0.8% carbon), the carbon will first precipitate out as large inclusions of cementite at
7442-582: The bird droppings, at an annual expense of ₹ 500,000 (US$ 6,000). In 2004, KoPT spent ₹ 6.5 million (US$ 78,000) to paint the entirety of 2.2 million square metres (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 litres 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
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#17327723320937564-494: The boundaries in hypoeutectoid steel. The above assumes that the cooling process is very slow, allowing enough time for the carbon to migrate. As the rate of cooling is increased the carbon will have less time to migrate to form carbide at the grain boundaries but will have increasingly large amounts of pearlite of a finer and finer structure within the grains; hence the carbide is more widely dispersed and acts to prevent slip of defects within those grains, resulting in hardening of
7686-453: 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 increasing 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 plying on
7808-559: 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
7930-416: 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
8052-506: The bridge from collisions with vehicles, so that compensation could be claimed from the miscreants. 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
8174-467: 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 4,000 feet (1,200 m). 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
8296-645: 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. In 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
8418-600: 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 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 daytime. From 19 August 1879,
8540-521: The characteristics of steel. Common alloying elements include: manganese , nickel , chromium , molybdenum , boron , titanium , vanadium , tungsten , cobalt , and niobium . Additional elements, most frequently considered undesirable, are also important in steel: phosphorus , sulphur , silicon , and traces of oxygen , nitrogen , and copper . Plain carbon-iron alloys with a higher than 2.1% carbon content are known as cast iron . With modern steelmaking techniques such as powder metal forming, it
8662-478: The common phrase "quids in"). Its origin is unknown: possible derivations include scudo , the name for a number of currency units used in Italy until the 19th century, introduced by Italian immigrants; or from Latin quid via the common phrase quid pro quo , literally, "what for what", or, figuratively, "An equal exchange or substitution". The term "nicker" (also both singular and plural) may also refer to
8784-468: The compound noun pound sterling was derived from a pound (weight) of these sterlings. The English word pound derives from the Latin expression lībra pondō , in which lībra is a noun meaning 'pound' and pondō is a noun, in the ablative case , meaning 'by weight'. The currency sign for the pound unit of sterling is £ , which (depending on typeface) may be drawn with one or two bars :
8906-416: 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
9028-422: The desired properties. Nickel and manganese in steel add to its tensile strength and make the austenite form of the iron-carbon solution more stable, chromium increases hardness and melting temperature, and vanadium also increases hardness while making it less prone to metal fatigue . To inhibit corrosion, at least 11% chromium can be added to steel so that a hard oxide forms on the metal surface; this
9150-419: The entire 705 metres (2,313 ft) long and 30 metres (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
9272-442: The existing bridge, then unless a temporary bridge is provided, there will be serious interruptions to the traffic while 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
9394-430: The fact that from the mid-19th century, the sterling/dollar exchange rate was transmitted via transatlantic cable. Historically almost every British coin had a widely recognised nickname, such as "tanner" for the sixpence and "bob" for the shilling . Since decimalisation these have mostly fallen out of use except as parts of proverbs. A common slang term for the pound unit is " quid " (singular and plural, except in
9516-581: 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: In view 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
9638-413: The final steel (either as solute elements, or as precipitated phases), impedes the movement of the dislocations that make pure iron ductile, and thus controls and enhances its qualities. These qualities include the hardness , quenching behaviour , need for annealing , tempering behaviour , yield strength , and tensile strength of the resulting steel. The increase in steel's strength compared to pure iron
9760-596: The finest steel in the world exported to the Roman, Egyptian, Chinese and Arab worlds at that time – what they called Seric Iron . A 200 BC Tamil trade guild in Tissamaharama , in the South East of Sri Lanka, brought with them some of the oldest iron and steel artifacts and production processes to the island from the classical period . The Chinese and locals in Anuradhapura , Sri Lanka had also adopted
9882-513: The form of charcoal) in a crucible, was produced in Merv by the 9th to 10th century AD. In the 11th century, there is evidence of the production of steel in Song China using two techniques: a "berganesque" method that produced inferior, inhomogeneous steel, and a precursor to the modern Bessemer process that used partial decarburization via repeated forging under a cold blast . Since
10004-454: The girders, were extensively damaged. Nearly 350 metres (1,150 ft) of 700 metres (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$ 60,000), about 8 tonnes of steel
10126-599: The hardenability of thick sections. High strength low alloy steel has small additions (usually < 2% by weight) of other elements, typically 1.5% manganese, to provide additional strength for a modest price increase. Recent corporate average fuel economy (CAFE) regulations have given rise to a new variety of steel known as Advanced High Strength Steel (AHSS). This material is both strong and ductile so that vehicle structures can maintain their current safety levels while using less material. There are several commercially available grades of AHSS, such as dual-phase steel , which
10248-476: 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
10370-491: The letter ⟨L⟩ for pound derives from medieval Latin documents: "L" was the abbreviation for libra , the Roman pound (weight), which in time became an English unit of weight defined as the tower pound . A "pound sterling" was literally a tower pound (weight) of sterling silver . In the British pre-decimal ( duodecimal ) currency system, the term £sd (or Lsd) for pounds, shillings and pence referred to
10492-439: The main production route. At the end of 2008, the steel industry faced a sharp downturn that led to many cut-backs. In 2021, it was estimated that around 7% of the global greenhouse gas emissions resulted from the steel industry. Reduction of these emissions are expected to come from a shift in the main production route using cokes, more recycling of steel and the application of carbon capture and storage technology. Steel
10614-675: The matter to Sir Basil Mott , who proposed a single span arch bridge . Charles Alfred O'Grady one of the Engineers In 1922, 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 S.W. Goode as president, S.N. Mallick, and W.H. Thompson, to investigate and report on the advisability of constructing
10736-450: The most part, however, p-block elements such as sulphur, nitrogen , phosphorus , and lead are considered contaminants that make steel more brittle and are therefore removed from steel during the melting processing. The density of steel varies based on the alloying constituents but usually ranges between 7,750 and 8,050 kg/m (484 and 503 lb/cu ft), or 7.75 and 8.05 g/cm (4.48 and 4.65 oz/cu in). Even in
10858-405: 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 road way 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
10980-597: The origin of the word "sterling". The Oxford English Dictionary states that the "most plausible" etymology is a derivation from the Old English steorra for "star" with the added diminutive suffix -ling , to yield "little star". The reference is to the silver penny used in Norman England in the twelfth century, which bore a small star. Another theory holds that the Hanseatic League
11102-436: The oxidation rate of iron increases rapidly beyond 800 °C (1,470 °F), it is important that smelting take place in a low-oxygen environment. Smelting, using carbon to reduce iron oxides, results in an alloy ( pig iron ) that retains too much carbon to be called steel. The excess carbon and other impurities are removed in a subsequent step. Other materials are often added to the iron/carbon mixture to produce steel with
11224-554: The pound. The currency of all the Crown Dependencies ( Guernsey , Jersey , Isle of Man ) and a third of British Overseas Territories ( British Antarctic Territory ; Falkland Islands and South Georgia and the South Sandwich Islands ; Gibraltar ; and Saint Helena, Ascension and Tristan da Cunha ) is either sterling or pegged to sterling at par. The other British Overseas Territories have
11346-602: The pound. The symbol for the shilling was " s ." – not from the first letter of "shilling", but from the Latin solidus . The symbol for the penny was " d .", from the French denier , from the Latin denarius (the solidus and denarius were Roman coins). A mixed sum of shillings and pence, such as 3 shillings and 6 pence, was written as "3/6" or "3 s . 6 d ." and spoken as "three and six" or "three and sixpence" except for "1/1", "2/1" etc., which were spoken as "one and
11468-449: The product but only locally relieves strains and stresses locked up within the material. Annealing goes through three phases: recovery , recrystallization , and grain growth . The temperature required to anneal a particular steel depends on the type of annealing to be achieved and the alloying constituents. Quenching involves heating the steel to create the austenite phase then quenching it in water or oil . This rapid cooling results in
11590-759: The production methods of creating wootz steel from the Chera Dynasty Tamils of South India by the 5th century AD. In Sri Lanka, this early steel-making method employed a unique wind furnace, driven by the monsoon winds, capable of producing high-carbon steel. Since the technology was acquired from the Tamilians from South India, the origin of steel technology in India can be conservatively estimated at 400–500 BC. The manufacture of wootz steel and Damascus steel , famous for its durability and ability to hold an edge, may have been taken by
11712-513: The reign of King Offa of Mercia (757–796), who introduced a "sterling" coin made by physically dividing a Tower pound (5,400 grains, 349.9 grams) of silver into 240 parts. In practice, the weights of the coins were not consistent, 240 of them seldom added up to a full pound; there were no shilling or pound coins and these units were used only as an accounting convenience . Halfpennies and farthings worth 1 ⁄ 2 and 1 ⁄ 4 penny respectively were also minted, but small change
11834-477: The solid-state, by heating the ore in a charcoal fire and then welding the clumps together with a hammer and in the process squeezing out the impurities. With care, the carbon content could be controlled by moving it around in the fire. Unlike copper and tin, liquid or solid iron dissolves carbon quite readily. All of these temperatures could be reached with ancient methods used since the Bronze Age . Since
11956-401: The steel. At the very high cooling rates produced by quenching, the carbon has no time to migrate but is locked within the face-centred austenite and forms martensite . Martensite is a highly strained and stressed, supersaturated form of carbon and iron and is exceedingly hard but brittle. Depending on the carbon content, the martensitic phase takes different forms. Below 0.2% carbon, it takes on
12078-561: The steel. The early modern crucible steel industry resulted from the invention of Benjamin Huntsman in the 1740s. Blister steel (made as above) was melted in a crucible or in a furnace, and cast (usually) into ingots. The modern era in steelmaking began with the introduction of Henry Bessemer 's process in 1855, the raw material for which was pig iron. His method let him produce steel in large quantities cheaply, thus mild steel came to be used for most purposes for which wrought iron
12200-512: 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
12322-561: The technology of that time, such qualities were produced by chance rather than by design. Natural wind was used where the soil containing iron was heated by the use of wood. The ancient Sinhalese managed to extract a ton of steel for every 2 tons of soil, a remarkable feat at the time. One such furnace was found in Samanalawewa and archaeologists were able to produce steel as the ancients did. Crucible steel , formed by slowly heating and cooling pure iron and carbon (typically in
12444-430: The then exchange rate) was declared for the firm whose design would be accepted. The initial construction process of the bridge was stalled due to 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
12566-473: 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$ 24,000) on covering the base of the steel pillars with fibreglass casing to prevent spit from corroding them. On 24 June 2005,
12688-525: The upper carbon content of steel, beyond which is cast iron. When carbon moves out of solution with iron, it forms a very hard, but brittle material called cementite (Fe 3 C). When steels with exactly 0.8% carbon (known as a eutectoid steel), are cooled, the austenitic phase (FCC) of the mixture attempts to revert to the ferrite phase (BCC). The carbon no longer fits within the FCC austenite structure, resulting in an excess of carbon. One way for carbon to leave
12810-428: The world's steel in 2023. Further refinements in the process, such as basic oxygen steelmaking (BOS), largely replaced earlier methods by further lowering the cost of production and increasing the quality of the final product. Today more than 1.6 billion tons of steel is produced annually. Modern steel is generally identified by various grades defined by assorted standards organizations . The modern steel industry
12932-520: 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 7 December 1941. The first vehicle to use the bridge was a solitary tram . The bridge is regarded "The Gateway to Kolkata, as it connects the city to Howrah Station". When commissioned in 1943, Howrah
13054-411: 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, a large number of the internal wells were completely undercut, allowing the whole weight of the caisson to be carried by the outside skin friction and
13176-470: Was adopted from the livre carolingienne system introduced by Charlemagne to the Frankish Empire . The penny was abbreviated to "d", from denarius , the Roman equivalent of the penny; the shilling to "s" from solidus (written with a long s , ſ , later evolving into a simple slash , / ); and the pound to "L" (subsequently £ ) from Libra or Livre . The origins of sterling lie in
13298-463: Was constructed with single monolith caissons of dimensions 55.31 m × 24.8 m with 21 shafts, each 6.25 metre 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
13420-623: 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. Eventually
13542-718: Was developed in Southern India and Sri Lanka in the 1st millennium BCE. Metal production sites in Sri Lanka employed wind furnaces driven by the monsoon winds, capable of producing high-carbon steel. Large-scale wootz steel production in India using crucibles occurred by the sixth century BC, the pioneering precursor to modern steel production and metallurgy. High-carbon steel was produced in Britain at Broxmouth Hillfort from 490–375 BC, and ultrahigh-carbon steel
13664-509: Was formerly used. The Gilchrist-Thomas process (or basic Bessemer process ) was an improvement to the Bessemer process, made by lining the converter with a basic material to remove phosphorus. Another 19th-century steelmaking process was the Siemens-Martin process , which complemented the Bessemer process. It consisted of co-melting bar iron (or steel scrap) with pig iron. These methods of steel production were rendered obsolete by
13786-490: 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. 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
13908-438: Was produced globally, with 630,000,000 tonnes (620,000,000 long tons; 690,000,000 short tons) recycled. Modern steels are made with varying combinations of alloy metals to fulfil many purposes. Carbon steel , composed simply of iron and carbon, accounts for 90% of steel production. Low alloy steel is alloyed with other elements, usually molybdenum , manganese, chromium, or nickel, in amounts of up to 10% by weight to improve
14030-706: Was produced in the Netherlands from the 2nd-4th centuries AD. The Roman author Horace identifies steel weapons such as the falcata in the Iberian Peninsula , while Noric steel was used by the Roman military . The Chinese of the Warring States period (403–221 BC) had quench-hardened steel, while Chinese of the Han dynasty (202 BC—AD 220) created steel by melting together wrought iron with cast iron, thus producing
14152-417: 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
14274-521: 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 a stiff yellow clay 26.5 m below ground level. The accuracy of sinking
14396-477: Was the 3rd-longest cantilever bridge in the world, behind Pont de Québec (549 metres (1,801 ft)) in Canada and Forth Bridge (521 metres (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 1,500 feet (460 m) between centers of main towers and
14518-471: Was the fourth-most-traded currency in the foreign exchange market , after the United States dollar , the euro , and the Japanese yen . Together with those three currencies and the renminbi , it forms the basket of currencies that calculate the value of IMF special drawing rights . As of late 2022, sterling is also the fourth most-held reserve currency in global reserves . The Bank of England
14640-576: Was the origin of its definition, manufacture, and name: the German name for the Baltic is Ostsee ( ' East Sea ' ) and from this the Baltic merchants were called Osterlings ( ' Easterlings ' ). In 1260, Henry III granted them a charter of protection and land for their kontor , the Steelyard of London , which by the 1340s was also called Esterlingeshalle ( ' Easterlings Hall ' ). Because
14762-467: Was to come from England were diverted for war effort in Europe. Out of 26,000 tons of steel, that was required for the bridge, only 3000 tons were supplied from England. In spite of the Japanese threat, the then (British) government of India pressed on with the construction. Tata Steel were asked to supply the remaining 23,000 tons of high tension steel. The Tatas developed the quality of steel required for
14884-1726: Was used. The repairs were completed in early 2006. The bridge has been shown in numerous films, such as Bimal Roy 's 1953 film Do Bigha Zamin , Ritwik Ghatak 's Bari Theke Paliye in 1958, Satyajit Ray 's Parash Pathar in the same year, Mrinal Sen 's Neel Akasher Neechey in 1959, Shakti Samanta 's Howrah Bridge (1958), that featured the famous song Mera Naam Chin Chin Chu and China Town (1962) and Amar Prem (1971), Amar Jeet's 1965 Teen Devian in 1965, Mrinal Sen 's 1972 National Award winning Bengali film Calcutta 71 and Sen's Calcutta Trilogy its sequel in 1973, Padatik , Richard Attenborough 's 1982 Academy Award winning film Gandhi , Goutam Ghose 's 1984 Hindi film Paar , Raj Kapoor 's Ram Teri Ganga Maili in 1985, Nicolas Klotz 's The Bengali Night in 1988, Roland Joffé 's English language film City of Joy in 1992, Florian Gallenberger 's Bengali film Shadows of Time in 2004, Mani Ratnam 's Bollywood film Yuva in 2004, Pradeep Sarkar 's 2005 Bollywood film Parineeta , Subhrajit Mitra 's 2008 Bengali film Mon Amour: Shesher Kobita Revisited , Mira Nair 's 2006 film The Namesake , Blessy 's 2008 Malayalam Film Calcutta News , Surya Sivakumar 's 2009 Tamil film Aadhavan , Imtiaz Ali 's 2009 Hindi film Love Aaj Kal , Abhik Mukhopadhyay 's 2010 Bengali film Ekti Tarar Khonje , Sujoy Ghosh 's 2012 Bollywood film Kahaani , Anurag Basu 's 2012 Hindi film Barfi! , Riingo Banerjee 's 2012 Bengali film Na Hannyate , Rana Basu's 2013 Bengali film Namte Namte , and Ali Abbas Zafar 's 2014 Hindi film Gunday and
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