91-640: Macapagal Bridge (Filipino: Tulay ng Macapagal ) is a steel cable-stayed bridge along Mayor Democrito D. Plaza II Avenue (also known as the Butuan Bypass Road) in Butuan , Agusan del Norte that crosses the Agusan River . It has a length of 908 m (2,979 ft), making it the second-longest bridge in Mindanao after Panguil Bay Bridge , and the third-longest cable-stayed bridge in
182-412: 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
273-531: 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
364-713: 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 ,
455-444: 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
546-428: 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
637-583: 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
728-445: 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
819-434: 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
910-412: 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
1001-534: 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
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#17327868014751092-453: 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
1183-477: 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
1274-672: 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
1365-636: 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
1456-416: 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
1547-403: 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
1638-403: 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
1729-405: 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
1820-408: 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
1911-691: 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
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#17327868014752002-551: 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
2093-547: 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
2184-651: The Department of Commerce and Police (DCP) in 1902, with two public works-related agencies, the Bureau of Engineering and Construction for public works projects and the Bureau of Architecture and Construction for the construction of public buildings. Both agencies were eventually merged into a bureau known as the Bureau of Public Works and was eventually subsumed into the DCP during reorganization in 1905. To keep pace with further developments in transportation and communications,
2275-655: 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
2366-563: The Philippines after the Marcelo Fernan Bridge and Cebu-Cordova Bridge . Initially named the "Second Magsaysay Bridge" during construction (referring to the nearby Magsaysay Bridge), the bridge was officially named after Philippine President Diosdado Macapagal when it was inaugurated in 2007. The bridge was constructed along with the 13.1 km (8.1 mi) Butuan Bypass Road, which aims to decongest traffic along
2457-689: The U.S. Bureau of Public Roads set up an office in the Philippines to coordinate with the Philippine Bureau of Public Works in implementing the Philippine highway network, which was in ruins. The DPWC was renamed in 1951 the Department of Public Works, Transportation and Communications , or DPWTC. In 1954, a body named the Bureau of Public Highways was established. This became a separate department on July 1, 1974. Two years later, with
2548-599: 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
2639-419: 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
2730-445: 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
2821-475: 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
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2912-626: 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
3003-481: 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
3094-676: The Agusan-Misamis Oriental Road in downtown Butuan, through official development assistance from the Japan Bank for International Cooperation worth PH₱ 2.2 billion. Prior to the construction of the bridge, the nearby Magsaysay Bridge was the only bridge in Butuan that spans the Agusan River. Built in 1957, the old truss bridge has deteriorated over time and has experienced heavy traffic congestion because of
3185-608: 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
3276-579: The Bureau of Communications and Transportation (Communicaciones y Meteologia), now the Department of Transportation , the DPWH was organized under a civil engineer known as the “Director General”. It was responsible for all public works projects being done in the islands. During the Philippine Revolution , public works duties were assumed by a new department known as the Department of War and Public Works (DWPW). Although initially included in
3367-653: The DCP was transformed into the Department of Commerce and Communications (DCC) in 1921. In 1931, the DCC was renamed by the Philippine Legislature the Department of Public Works and Communication (DPWC). Upon the inauguration of the Commonwealth of the Philippines in 1935, the DPWC was reorganized to contain the following bureaus: the Bureau of Public Works, Ports, Aeronautics, Coast and Geodetic Survey,
3458-670: The DEO for six years after project completion. While no entity had the formal responsibility for O&M of the project, the DEO voluntarily conducted O&M to the extent possible. With the Butuan Bypass Road converted into a national road by virtue of Department Order No. 51 in May 2013, responsibility for O&M of the bridge and bypass road formally delegated to the DEO. The bridge had its first major rehabilitation in April 2010 after it
3549-470: 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
3640-574: The Macapagal Bridge and the Butuan Bypass Road was expected to last 70 months from the signing of the loan agreement in August 2000 up to the expected completion of civil works by May 2006. However, the actual construction took 82 months because of delays due to administrative procedures, delayed payment of billings for the contractors, flooding of the Agusan River due to inclement weather, delays in land acquisition and soft ground encountered near
3731-811: The Mandate to “be the State's engineering and construction arm” and, as such, it is “tasked to carry out the policy” of the State to “maintain an engineering and construction arm and continuously develop its technology, for the purposes of ensuring the safety of all infrastructure facilities and securing for all public works and highways the highest efficiency and the most appropriate quality in construction” and shall be responsible for “(t)he planning, design, construction and maintenance of infrastructure facilities, especially national highways, flood control and water resources development systems, and other public works in accordance with national development objectives,” provided that,
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3822-635: The Metropolitan Water District Division of Marine, Railway and Repair Shop, National Radio Broadcasting, the Irrigation Council and Board of Examiners for Civil, Mechanical, Chemical and Mining Engineers. During World War II , the DPWC's offices were destroyed in the Japanese occupation of the Philippines. It resumed operations in 1946, albeit with limited funds and manpower. To assist reconstruction efforts,
3913-739: The Ministry of Public Works and Highways in 1981. On January 30, 1987, with the approval of the 1987 Constitution, the Ministry was reconfigured into a department. In July 1991, the Sandiganbayan issued a warrant of arrest against former minister Jesus Hipolito and former deputy minister Aber Canlas, as well as eight other engineers of MPWH, charging them with graft for their involvement in "ghost" dredging projects meant for improving Metro Manila 's rivers in 1985 that cost up to ₱200 million. The State shall maintain an engineering and construction arm and continuously develop its technology, for
4004-701: The Subic Bay Port Development Project. Of this loaned amount, JP¥ 3,549 million was allocated for the project. However, after President Estrada was removed from office during the Second EDSA Revolution , implementation of the project fell upon the newly installed administration of President Gloria Macapagal Arroyo . The Macapagal Bridge, along with the Butuan Bypass Road, was constructed by a joint venture of Japanese engineering firms Nippon Steel Corporation and TOA Corporation, who were selected as main contractors after
4095-480: 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. Department of Public Works and Highways The Department of Public Works and Highways ( Filipino : Kagawaran ng mga Pagawain at Lansangang Bayan ), abbreviated as DPWH , is the executive department of the Philippine government solely vested with
4186-526: The adoption of the 1976 amendments to the 1973 Constitution , the department became the Ministries of Public Works, Transportation and Communications, and Public Highways, respectively. In 1979, the MPWTC was split into two ministries, the Ministry of Public Works (MPW) and the Ministry of Transportation and Communications (MOTC). After two years, the public works and highways ministries were merged, becoming
4277-401: 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
4368-436: 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
4459-471: 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
4550-494: 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
4641-515: The bridge abutment, which required additional sub-surface investigations and design revisions. Civil works for both the bridge and the bypass road began in May 2004 and were completed in May 2007. Macapagal Bridge was completed and opened to traffic on the second week of April 2007. Almost a month after, on May 3, 2007, the bridge was formally inaugurated during a ceremony led by Department of Public Works and Highways (DPWH) Secretary Manuel Bonoan, who represented President Arroyo. Also present during
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#17327868014754732-717: The bridge carries across the Agusan River was completed in 2011 and opened to vehicular traffic the following year. The road connects the Bancasi Airport along the Butuan-Cagayan de Oro-Iligan Road with the Surigao-Agusan-Davao Road and bypassing downtown Butuan, thus easing traffic congestion in the city, and in the Magsaysay Bridge, which has banned vehicles over 15 tons from passing over the bridge since 2008 due to its old age. With
4823-408: The bridge piers in the event of heavy rains. This resulted in the reduction of the length of the approach bridge from 630 m (2,070 ft) to 548 m (1,798 ft), while the total length of the bridge was increased from 885 m (2,904 ft) to 908 m (2,979 ft) because abutments had to be built in a location away from the Agusan River to avoid the soft ground. Construction of
4914-534: The bridge to traffic and rerouting of traffic to the old Magsaysay Bridge. 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
5005-427: The bypass road and an increase in investments and employment opportunities in the city. The District Engineering Office (DEO) of Butuan under DPWH Region XIII was supposed to be in charge of operation and maintenance (O&M) for both the Macapagal Bridge and the Butuan Bypass Road. However, the responsibility for O&M was not delegated from DPWH Project Management Office - Philippine Japan Highway Loan (PMO-PJHL) to
5096-455: 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
5187-427: The detailed engineering design and construction supervision for the project, including the preparation of conceptual and preliminary designs, detailed design, contract drawings, technical specification, cost estimates, and bid documents. During the design phase of the project, the length of the main span was increased from 255 m (837 ft) to 360 m (1,180 ft) to prevent falling debris from clashing with
5278-452: 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
5369-480: The exception only of specialized projects undertaken by Government corporate entities with established technical capability and as directed by the President of the Philippines or as provided by law; (5) Provide the works supervision function for all public works constructions and ensure that actual construction is done in accordance with approved government plans and specifications; (6) Assist other agencies, including
5460-491: The exercise of which “shall be decentralized to the fullest extent feasible.” History of the DPWH stretches back as far as the history of Philippine government itself. During Spanish times, the Spanish constructed the first roads in the Philippines using significant forced labor . These public works projects were not only used in the connection of towns and fortresses, but also in improving communications. As Spain expanded
5551-648: 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
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#17327868014755642-579: 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
5733-513: 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
5824-599: 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
5915-741: The inauguration are Akiri Sugiyama, economic minister of the Embassy of Japan in Manila, who represented Japanese Ambassador to the Philippines Ryuchiro Yamazaki; DPWH Assistant Secretary Rafael Yabut; Mindanao Economic Development Council Assistant Secretary Jose Aquino II; Japan Bank for International Cooperation (JBIC) chief representative Hiroshi Togo; Agusan del Norte First District Representative Leovigildo Banaag ; and Japanese engineers from TOA Corporation, Nippon Steel Corporation and Katahira International. The bridge, which
6006-482: The increasing vehicular volume in the city, thus necessitating the construction of a new bridge. Since the administration of Philippine President Fidel Ramos , there have been plans developed by the City Council for a bypass road and bridge that would alleviate the traffic problem along Magsaysay Bridge. During the administration of Philippine President Joseph Estrada , the development of a bypass road and bridge
6097-410: The loan agreement was signed. TOA Corporation was responsible for constructing the single main pylon made of reinforced concrete, the foundations to support the bridge superstructure, and all civil works for the road section. A joint venture of Japanese firms Katahira and Engineers International and Sogo Engineering, Inc. and Filipino companies Proconsult, Inc., TCGI Engineers and DCCD Engineering provided
6188-679: The local governments, in determining the most suitable entity to undertake the actual construction of public works projects; (7) Maintain or cause to be maintained all highways, flood control, and other public works throughout the country except those that are the responsibility of other agencies as directed by the President of the Philippines or as provided by law; (8) Provide an integrated planning for highways, flood control and water resource development systems, and other public works; (9) Classify road and highways into national, regional, provincial, city, municipal, and barangay roads and highways, based on objective criteria it shall adopt; provide or authorize
6279-439: 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
6370-450: 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
6461-446: 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
6552-463: The opening of the Macapagal Bridge, travel time between Libertad and Tiniwisan districts of the city was reduced to 13 minutes. Traffic congestion along Magsaysay Bridge also eased, reducing travel time from 30 minutes to just 16.5 minutes after Macapagal Bridge opened. Overall, transportation of goods between Caraga Region and other regions in Mindanao became more efficient, resulting in an increase in residential and commercial development in areas along
6643-615: The planning, design, construction, maintenance, or operation of infrastructure facilities; (2) Develop and implement effective codes, standards, and reasonable guidelines to ensure the safety of all public and private structures in the country and assure efficiency and proper quality in the construction of public works; (3) Ascertain that all public works plans and project implementation designs are consistent with current standards and guidelines; (4) Identify, plan, secure funding for, program, design, construct or undertake prequalification, bidding, and award of contracts of public works projects with
6734-574: The portfolio of the Department of War (now the Department of National Defense ), public works projects were so important to the war effort that public works were also prioritized through this department. During the American period, public works projects were initially put in the hands of the U.S. Army Corps of Engineers . However, this was transferred to a department known as the "Provincial Supervisions" on February 6, 1901. This eventually became
6825-449: 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
6916-759: 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
7007-438: The purposes of ensuring the safety of all infrastructure facilities and securing for all public works and highways the highest efficiency and the most appropriate quality in construction. The planning, design, construction and maintenance of infrastructure facilities, especially national highways, flood control and water resources development systems, and other public works in accordance with national development objectives, shall be
7098-426: 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
7189-435: The responsibility of such an engineering and construction arm. However, the exercise of this responsibility shall be decentralized to the fullest extent feasible. The Department of Public Works and Highways shall be the State's engineering and construction arm and is tasked to carry out the policy enunciated above (Section 2, Ibid.). The department, in order to carry out its mandate, shall: (1) Provide technical services for
7280-610: The scale of its public works projects, it resorted to a policy of attraction through public works projects. In 1867, in order to pursue this objective, the King of Spain by decree designated the Spanish Governor-General as the Chief of Public Works assisted by Junta Consultiva through a Royal Degree in 1867. It was in 1868 that the DPWH was born as the Bureau of Public Works and Highways, or Obras Publicas. Alongside
7371-401: 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
7462-561: 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
7553-561: 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
7644-525: 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
7735-718: 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
7826-420: Was discovered in their routine inspection that the foundation of the bridge had been sinking deeper into the Agusan River due to the softening of the soils and rocks where the abutment was built. They feared that the bridge might sink deeper and eventually collapse if no rehabilitation works are immediately done. The rehabilitation work lasted 10 months, thereby forcing the City Council to order temporary closure of
7917-509: 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
8008-639: Was included in his Mindanao 2000 Development Plan, which was part of his administration's effort to develop transportation infrastructure within the island. In August 2000, the Japan Bank for International Cooperation included the Second Magsaysay Bridge and the Butuan Bypass Road in its Special Yen (ODA) Loan Scheme worth JP¥ 34,723 million, along with the New Iloilo Airport Development Project and
8099-628: Was initially named "Second Magsaysay Bridge" during construction after the nearby Magsaysay Bridge 3 km (1.9 mi) to the north, was officially named President Diosdado Macapagal Bridge more than three years after its inauguration, after President Arroyo signed Republic Act No. 10051 on March 19, 2010. It's the third bridge named after former Philippine President Diosdado Macapagal after Macapagal Bridge in Cagayan de Oro and Macapagal Bridge in Marikina , Metro Manila . The Butuan Bypass Road which
8190-438: 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
8281-757: 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
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