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97-614: Heavy traffic and harsh New England weather had taken their toll on the original Moses Wheeler Bridge. It had been rated as 'structurally deficient' during recent inspections, with accelerating deterioration of the structural steel and the fracture critical pin and hanger assemblies being of particular concern; the latter problem gained increased attention due to the collapse of the similar-in-design Mianus River Bridge further west in Greenwich in 1983. The Connecticut Department of Transportation (CONNDOT) began drawing up plans to replace

194-412: 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

291-531: A brittle alloy commonly called pig iron . Alloy steel is steel to which other alloying elements have been intentionally added to modify 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

388-713: 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 ,

485-444: 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

582-648: A circle and seam-welded). The terms angle iron , channel iron , and sheet iron have been in common use since before wrought iron was replaced by steel for commercial purposes. They have lived on after the era of commercial wrought iron and are still sometimes heard today, informally, in reference to steel angle stock, channel stock, and sheet, despite that they are misnomers (compare "tin foil", still sometimes used informally for aluminum foil). In formal writing for metalworking contexts, accurate terms like angle stock , channel stock , and sheet are used. Most steels used throughout Europe are specified to comply with

679-495: A construction project is begun. Structures consisting of both materials utilize the benefits of structural steel and reinforced concrete. This is already common practice in reinforced concrete in that the steel reinforcement is used to provide steel's tensile strength capacity to a structural concrete member. A commonly seen example would be parking garages. Some parking garages are constructed using structural steel columns and reinforced concrete slabs. The concrete will be poured for

776-438: A cutting torch is typically used. Oxy-fuel torches are the most common technology and range from simple hand-held torches to automated CNC coping machines that move the torch head around the structural element in accordance with cutting instructions programmed into the machine. Fabricating flat plate is performed on a plate processing center where the plate is laid flat on a stationary 'table' and different cutting heads traverse

873-411: A fender system to protect the bridge piers from ship collisions. Aesthetic features are also included, among which is encasing the bridge piers with decorative granite and aesthetic lighting. The STV Group designed the replacement bridge. Environmental studies for the new bridge were completed in 2005, and CONNDOT awarded a $ 60 million contract to Torrington, Connecticut -based O&G Industries for

970-428: 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

1067-415: A final decision is made. The tallest structures today (commonly called " skyscrapers " or high-rise ) are constructed using structural steel due to its constructability, as well as its high strength-to-weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength-to-weight ratio. This is due to the much larger volume required for a structural concrete member to support

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1164-583: A hard oxide forms on the metal surface; this 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

1261-445: 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

1358-402: A high load without excessive sagging . The shapes available are described in many published standards worldwide, and a number of specialist and proprietary cross sections are also available. While many sections are made by hot or cold rolling , others are made by welding together flat or bent plates (for example, the largest circular hollow sections are made from flat plate bent into

1455-434: A higher than 2.1% carbon content are known as cast iron . With modern steelmaking techniques such as powder metal forming, it 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

1552-412: 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

1649-534: 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

1746-453: 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

1843-448: A structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before

1940-477: A subsequent step. Other materials are often added to the iron/carbon mixture to produce steel with 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

2037-672: 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

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2134-431: Is 1,130 °C (2,070 °F). Steel never turns into a liquid below this temperature. Pure Iron ('Steel' with 0% Carbon) starts to melt at 1,492 °C (2,718 °F), and is completely liquid upon reaching 1,539 °C (2,802 °F). Steel with 2.1% Carbon by weight begins melting at 1,130 °C (2,070 °F), and is completely molten upon reaching 1,315 °C (2,399 °F). 'Steel' with more than 2.1% Carbon

2231-450: Is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form-work, etc.) is constantly changing. If a structure could be constructed using either material,

2328-419: Is added, the temperature falls to a minimum 724 °C (1,335 °F) for eutectic steel (steel with only .83% by weight of carbon in it). As 2.1% carbon (by mass ) is approached, the austenizing temperature climbs back up, to 1,130 °C (2,070 °F). Similarly, the melting point of steel changes based on the alloy. The lowest temperature at which a plain carbon steel can begin to melt, its solidus ,

2425-636: 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 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

2522-416: 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 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

2619-695: Is below 400 °C. In China, Europe and North America (e.g., ASTM E-119), this is approximately 1000–1300 °F (530–810 °C). The time it takes for the steel element that is being tested to reach the temperature set by the test standard determines the duration of the fire-resistance rating . Heat transfer to the steel can be slowed by the use of fireproofing materials , thus limiting steel temperature. Common fireproofing methods for structural steel include intumescent , endothermic, and plaster coatings as well as drywall, calcium silicate cladding, and mineral wool insulating blankets. Concrete building structures often meet code required fire-resistance ratings, as

2716-403: 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

2813-403: 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

2910-405: Is extracted from iron ore by removing the oxygen through its combination with a preferred chemical partner such as carbon which 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

3007-408: 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

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3104-647: Is introduced by the Construction Products Directive (CPD) . The CPD is a European Directive that ensures the free movement of all construction products within the European Union. Because steel components are "safety critical", CE Marking is not allowed unless the Factory Production Control (FPC) system under which they are produced has been assessed by a suitable certification body that has been approved to

3201-422: Is just one possible example of many structures that may use both reinforced concrete and structural steel. A structural engineer understands that there are an infinite number of designs that will produce an efficient, safe, and affordable building. It is the engineer's job to work alongside the owners, contractors, and all other parties involved to produce an ideal product that suits everyone's needs. When choosing

3298-432: Is no longer Steel, but is known as Cast iron . Steel loses strength when heated sufficiently. The critical temperature of a steel member is the temperature at which it cannot safely support its load . Building codes and structural engineering standard practice defines different critical temperatures depending on the structural element type, configuration, orientation, and loading characteristics. The critical temperature

3395-691: 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

3492-502: Is often considered the temperature at which its yield stress has been reduced to 60% of the room temperature yield stress. In order to determine the fire resistance rating of a steel member, accepted calculations practice can be used, or a fire test can be performed, the critical temperature of which is set by the standard accepted to the Authority Having Jurisdiction, such as a building code. In Japan, this

3589-551: 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

3686-547: 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

3783-500: Is usually done with a bandsaw . A beam drill line (drill line) has long been considered an indispensable way to drill holes and mill slots into beams, channels and HSS elements. CNC beam drill lines are typically equipped with feed conveyors and position sensors to move the element into position for drilling, plus probing capability to determine the precise location where the hole or slot is to be cut. For cutting irregular openings or non-uniform ends on dimensional (non-plate) elements,

3880-478: The European standard EN 10025 . However, many national standards also remain in force. Typical grades are described as the 'S275J2' or 'S355K2W'. In these examples, 'S' denotes structural rather than engineering steel; 275 or 355 denotes the yield strength in newtons per square millimetre or the equivalent megapascals ; J2 or K2 denotes the materials toughness by reference to Charpy impact test values; and

3977-655: 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

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4074-599: 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

4171-419: 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 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

4268-525: The 'W' denotes weathering steel . Further letters can be used to designate fine grain steel ('N' or 'NL'); quenched and tempered steel ('Q' or 'QL'); and thermomechanically rolled steel ('M' or 'ML'). 1. S275JOH Specification S275JOH is steel grade in EN 10219 specification, EN 10210 standard. And the most widely used specification is EN10219 standard, which is Cold formed welded structural hollow sections of non-alloy and fine grain steels. EN10219-1 specifies

4365-445: 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

4462-475: 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

4559-626: 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 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

4656-481: 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 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

4753-608: 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

4850-665: The European Commission. In the case of steel products such as sections, bolts and fabricated steelwork the CE Marking demonstrates that the product complies with the relevant harmonized standard. For steel structures the main harmonized standards are: The standard that covers CE Marking of structural steelwork is EN 1090 -1. The standard has come into force in late 2010. After a transition period of two years, CE Marking will become mandatory in most European Countries sometime early in 2012. The official end date of

4947-470: 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

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5044-401: 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 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

5141-436: 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

5238-471: 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

5335-494: 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

5432-463: The bridge in 1996. Originally CONNDOT planned to construct the new bridge to the south of the existing one, away from 115 kilovolt high tension wires that run atop the nearby Housatonic River Railroad Bridge . Stratford residents and officials demanded the new bridge be built to the north of the existing span, closer to the Metro-North bridge and the power lines. A compromise was reached where

5529-484: The center portion of the new span. By the end of 2015, construction of the new Moses Wheeler Bridge reached substantial completion, with final paving and striping completed in spring 2016. During the summer of 2007, CONNDOT performed a $ 6.9 million emergency repair project to the Moses Wheeler Bridge after several large holes opened up in the bridge deck, and advanced deterioration of the structural steel

5626-406: The cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of

5723-455: 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 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

5820-418: The concrete thickness over the steel rebar provides sufficient fire resistance. However, concrete can be subject to spalling , particularly if it has an elevated moisture content. Although additional fireproofing is not often applied to concrete building structures, it is sometimes used in traffic tunnels and locations where a hydrocarbon fuel fire is more likely, as flammable liquid fires provides more heat to

5917-708: The discretion of the steel producer. S275JOH carbon steel pipes can be made in ERW, SAW or seamless process. All S275JOH steel material and S275JOH pipes should conform to EN10219 standards. The normal yield strength grades available are 195, 235, 275, 355, 420, and 460, although some grades are more commonly used than others e.g. in the UK, almost all structural steel is grades S275 and S355. Higher grades are available in quenched and tempered material (500, 550, 620, 690, 890 and 960 – although grades above 690 receive little if any use in construction at present). A set of Euronorms define

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6014-452: The economies of melting and casting, can be heat treated after casting to make malleable iron or ductile iron objects. Steel 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

6111-648: 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

6208-579: 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 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

6305-445: The form of an elongated beam having a profile of a specific cross section . Structural steel shapes, sizes, chemical composition , mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries. Most structural steel shapes, such as Ɪ-beams , have high second moments of area , which means they are very stiff in respect to their cross-sectional area and thus can support

6402-513: 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

6499-450: The foundational footings, giving the parking garage a surface to be built on. The steel columns will be connected to the slab by bolting and/or welding them to steel studs extruding from the surface of the poured concrete slab. Pre-cast concrete beams may be delivered on site to be installed for the second floor, after which a concrete slab may be poured for the pavement area. This can be done for multiple stories. A parking garage of this type

6596-599: 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

6693-805: The initial phase of work in July 2009. Construction on the first phase of replacing the bridge, including the foundations for the new bridge piers and temporary work trusses in the Housatonic River began in September 2009. The $ 166.5 million contract to build the remainder of the new bridge and demolish the existing span was awarded to a joint venture between Chicago, Illinois -based Walsh Construction Company and Denver, Colorado -based PCL Constructors (also referred to in contract documents as Walsh/PCL Joint Venture II) in August 2011. Walsh/PCL opted to use

6790-439: 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

6887-450: 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

6984-446: 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 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

7081-401: The new bridge will use approximately the same alignment as the original one. To make this possible, the new bridge was built substantially wider than the old one, which will also allow a future expansion with restriping of the travel lanes. The project was completed in three stages: the first two stages consisted of constructing the outer parts of the new bridge that carry the two outer lanes and

7178-468: The new northbound lanes in June 2013. In December 2013, northbound traffic was shifted from the old bridge to the new northbound lanes, at which point the remainder of the original 1958 structure was taken out of service and removed. During the summer of 2014, three large gantry cranes were assembled in the median of I-95 to facilitate the removal of structural steel from the original span and construction of

7275-416: The original bridge did not have. In addition, the left shoulders were built wide enough to accommodate a future widening to eight lanes. Two design options were developed for the new 14-span structure: one option using segmented concrete hollow box girders, and the other using continuous steel plate girders. The bridge is designed for seismic loading to withstand a major earthquake. Additionally, it includes

7372-405: The outer shoulder, while three lanes of traffic were maintained on the existing bridge. During the final stage of construction, three lanes of traffic were shifted to the new outer spans, to allow crews to demolish the original span and complete the center portion of the new bridge. The new bridge, like the original one, accommodates six lanes of traffic, but has full left and right shoulders which

7469-562: The plate from a gantry-style arm or "bridge". The cutting heads can include a punch, drill or torch. 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 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

7566-449: 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

7663-759: 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

7760-426: 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 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

7857-410: The same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low-rise buildings, or those with several stories or less. Low-rise buildings distribute much smaller loads than high-rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that

7954-601: The shape of a set of standard structural profiles: Steels used for building construction in the US use standard alloys identified and specified by ASTM International . These steels have an alloy identification beginning with A and then two, three, or four numbers. The four-number AISI steel grades commonly used for mechanical engineering, machines, and vehicles are a completely different specification series. The standard commonly used structural steels are: The concept of CE marking for all construction products and steel products

8051-405: The steel plate girder design option. Walsh/PCL commenced work to widen I-95 on the east and west approaches and began erecting the bridge piers for the new Moses Wheeler Bridge in September 2011. Crews shifted I-95 traffic to the southern half of the roadway so the northern half of the highway, including several smaller overpasses could rebuilt and expanded. On January 17, 2013, southbound traffic

8148-401: 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

8245-561: 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

8342-475: The structural element as compared to a fire involving ordinary combustibles during the same fire period. Structural steel fireproofing materials include intumescent, endothermic and plaster coatings as well as drywall , calcium silicate cladding, and mineral or high temperature insulation wool blankets. Attention is given to connections, as the thermal expansion of structural elements can compromise fire-resistance rated assemblies. Cutting workpieces to length

8439-454: The structural materials for their structure, the engineer has many variables to consider, such as the cost, strength/weight ratio, sustainability of the material, constructability, etc. The properties of steel vary widely, depending on its alloying elements. The austenizing temperature, the temperature where a steel transforms to an austenite crystal structure, for steel starts at 900 °C (1,650 °F) for pure iron, then, as more carbon

8536-423: The technical delivery conditions for cold formed welded structural hollow sections of circular, square or rectangular forms and applies to structural hollow sections formed cold without subsequent heat treatment. Requirements for S275JOH pipe tolerances, dimensions and sectional s275 pipe properties are contained in EN 10219-2. 2. S275JOH Steel Pipes manufacture Process The steel manufacturing process shall be at

8633-561: 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

8730-583: The transition period is July 1, 2014. Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete , masonry , and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete . When designing

8827-525: 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

8924-718: 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

9021-441: Was discovered during a routine inspection. The project involved a full-depth patch and repair of the bridge deck, roadway resurfacing, and reinforcement of key superstructure components to ensure the bridge could remain in service until the new bridge can be built. Structural steel Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take

9118-509: 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

9215-438: 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

9312-757: 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

9409-525: Was shifted onto the completed northern third of the new bridge and approaches. Northbound traffic was shifted onto the former southbound lanes of the old bridge on January 26, 2013. The Walsh/PCL construction team began demolishing the northbound portion of the old bridge and approaches in February 2013. Demolition of the old northbound span was completed in May 2013, and crews began erecting structural steel for

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