A construction worker is a tradesperson, laborer, or professional employed in the physical construction of the built environment and its infrastructure. The term construction worker is a generic term and most construction workers are described by the type of work they perform. Construction workers may colloquially be referred to as "hard hat workers" or "hard hats", as they wear hardhats for safety. Construction workers work under a construction foreman. While most construction workers learn on the job as an informal apprentice to an experienced tradesman, formal apprenticeship programs are common in developed countries with trade unions; the division of labor of construction encompasses a diverse range of manual labor. Among the most common construction trades are those of carpenter, heavy equipment operator, laborer, plasterer, pipefitter, sheet metal worker, steel fixer, welder. Construction safety is important to ensure a safe environment for the workers. All construction workers need to be educated on safety at each construction site to minimize injury.
In 2008, a Human Rights Watch report described unsafe and unfair working conditions and failure on the part of the Chinese government to enforce labor standards in the construction industry. The International Labour Organization estimated that, at the end of 2006, 90% of the 40 million construction workers in China were migrant workers. Many of the migrant workers turned to construction work after their farming communities collapsed into poverty. In the United States, illegal immigrant labor is prevalent in the construction industry; because of the questionable legal status of these workers, employers have the ability to commit crimes such as wage theft and violation of workplace standards without fear of facing consequences. Similar abuse of immigrant labor is a problem in Qatar during the lead up to the 2022 FIFA World Cup where workers from poor countries in the Indian Sub-continent are forced to work in desert conditions for as little as €6.20 a day. Construction and Maintenance at Curlie
A living wage is the minimum income necessary for a worker to meet their basic needs. Needs are defined to include food and other essential needs such as clothing; the goal of a living wage is to allow a worker to afford a decent standard of living. Due to the flexible nature of the term "needs", there is not one universally accepted measure of what a living wage is and as such it varies by location and household type. A living wage, in some nations such as the United Kingdom and New Zealand means that a person working 40 hours a week, with no additional income, should be able to afford the basics for a modest but decent life, such as, shelter, transport, health care, child care. Living wage advocates have further defined a living wage as the wage equivalent to the poverty line for a family of four; the income would have to allow the family to'secure food, clothing, health care and other necessities of living in modern society'. A definition of a living wage used by the Greater London Authority is the threshold wage, calculated as an income of 60% of the median, an additional 15% to allow for unforeseen events.
The living wage differs from the minimum wage in that the latter is set by national law and can fail to meet the requirements to have a basic quality of life which leaves the family to rely on government programs for additional income. Living wages, on the other hand, have only been adopted in municipalities. In economic terms, the living wage is similar to the minimum wage. In the 1990s, the first contemporary living wage campaigns were launched by community initiatives in the US addressing increasing poverty faced by workers and their families, they argued that the employee and community all benefited with a living wage. Employees would be more willing to work, helping the employer reduce worker turnover, it would help the community when the citizens have enough to have a decent life; these campaigns came about as a response to Reaganomics and Thatcherism in the US and UK which shifted macroeconomic policy towards neoliberalism. A living wage, by increasing the purchasing power of low income workers, is supported by Keynesian and post-Keynesian economics which focuses on stimulating demand in order to improve the state of the economy.
The concept of a living wage, though it was not defined as such, can be traced back to the works of ancient Greek philosophers such as Plato and Aristotle. Both argued for an income that considers needs those that ensure the communal good. Aristotle saw self-sufficiency as a requirement for happiness which he defined as, ‘that which on its own makes life worthy of choice and lacking in nothing’; as he placed the responsibility in ensuring that the poor could earn a sustainable living in the state, his ideas are seen as an early example of support for a living wage. The evolution of the concept can be seen on in medieval scholars such as Thomas Aquinas who argued for a'just wage'; the concept of a just wage was related to that of just prices, which were those that allowed everyone access to necessities. Prices and wages that prevented access to necessities were considered unjust as they would imperil the virtue of those without access. In Wealth of Nations, Adam Smith recognized that rising real wages lead to the "improvement in the circumstances of the lower ranks of people" and are therefore an advantage to society.
Growth and a system of liberty were the means by which the laboring poor were able to secure higher wages and an acceptable standard of living. Rising real wages are secured by growth through increasing productivity against stable price levels, i.e. prices not affected by inflation. A system of liberty, secured through political institutions whereupon the "lower ranks of people" could secure the opportunity for higher wages and an acceptable standard of living. Servants and workmen of different kinds, make up the far greater part of every great political society, but what improves the circumstances of the greater part can never be regarded as an inconvenience to the whole. No society can be ﬂourishing and happy, of which the far greater part of the members are poor and miserable, it is but equity, that they who feed and lodge the whole body of the people, should have such a share of the produce of their own labour as to be themselves tolerably well fed and lodged. Based on these writings, Smith advocated that labor should receive an equitable share of what labor produces.
For Smith, this equitable share amounted to more than subsistence. Smith the interests of land with overarching societal interests, he reasoned that as wages and rents rise, as a result of higher productivity, societal growth will occur thus increasing the quality of life for the greater part of its members. Like Smith, supporters of a living wage argue that the greater good for society is achieved through higher wages and a living wage, it is argued that government should in turn attempt to align the interests of those pursuing profits with the interests of the labor in order to produce societal advantages for the majority of society. Smith argued that higher productivity and overall growth led to higher wages that in turn led to greater benefits for society. Based on his writings, one can infer that Smith would support a living wage commensurate with the overall growth of the economy. This, in turn, would lead to more happiness and joy for people, while helping to keep families and people out of poverty.
Political institutions can create a system of liberty for individuals to ensure opportunity for higher wages through higher production and thus stable growth for society. In 1891, Pope Le
Pliers are a hand tool used to hold objects possibly developed from tongs used to handle hot metal in Bronze Age Europe. They are useful for bending and compressing a wide range of materials. Pliers consist of a pair of metal first-class levers joined at a fulcrum positioned closer to one end of the levers, creating short jaws on one side of the fulcrum, longer handles on the other side; this arrangement creates a mechanical advantage, allowing the force of the hand's grip to be amplified and focused on an object with precision. The jaws can be used to manipulate objects too small or unwieldy to be manipulated with the fingers. Pincers are a similar tool with a different type of head used for cutting and pulling, rather than squeezing. Tools designed for safely handling hot objects are called tongs. Special tools for making crimp connections in electrical and electronic applications are called "crimping pliers". There are many kinds of pliers made for various specific purposes; as pliers in the general sense are an ancient and simple invention, no single point in history, or inventor, can be credited.
Early metal working processes from several millennia BCE would have required plier-like devices to handle hot materials in the process of smithing or casting. Development from wooden to bronze pliers would have happened sometime prior to 3000 BCE. Among the oldest illustrations of pliers are those showing the Greek god Hephaestus in his forge; the number of different designs of pliers grew with the invention of the different objects which they were used to handle: horseshoes, wire, pipes and electronic components. The basic design of pliers has changed little since their origins, with the pair of handles, the pivot, the head section with the gripping jaws or cutting edges forming the three elements; the materials used to make pliers consist of steel alloys with additives such as vanadium or chromium, to improve strength and prevent corrosion. The metal handles of pliers are fitted with grips of other materials to ensure better handling; the jaws vary in size, from delicate needle-nose pliers to heavy jaws capable of exerting much pressure, shape, from basic flat jaws to various specialized and asymmetrical jaw configurations for specific manipulations.
The surfaces are textured rather than smooth, to minimize slipping. A plier-like tool designed for cutting wires is called diagonal pliers; some pliers for electrical work are fitted with wire-cutter blades either built into the jaws or on the handles just below the pivot. Where it is necessary to avoid scratching or damaging the workpiece, as for example in jewellery and musical instrument repair, pliers with a layer of softer material such as aluminium, brass, or plastic over the jaws are used. Much research has been undertaken to improve the design of pliers, to make them easier to use in difficult circumstances; the handles can be bent, for example, so that the load applied by the hand is aligned with the arm, rather than at an angle, so reducing muscle fatigue. It is important for factory workers who use pliers continuously and prevents carpal tunnel syndrome. Nipper How pliers are made
The Chrysler Building is an Art Deco–style skyscraper located on the East Side of Midtown Manhattan in New York City, at the intersection of 42nd Street and Lexington Avenue in the Turtle Bay neighborhood of Manhattan. At 1,046 feet, the structure was the world's tallest building for 11 months before it was surpassed by the Empire State Building in 1931, it is the tallest brick building in the world with a steel framework. As of 2018, the Chrysler is the eighth-tallest building in the city, tied with The New York Times Building. A project of real estate developer and former New York State Senator William H. Reynolds, the building was constructed by Walter Chrysler, the head of the Chrysler Corporation, served as the corporation's headquarters from 1930 until the mid-1950s; the Chrysler Building's construction was characterized by a competition with 40 Wall Street and the Empire State Building to become the world's tallest building. Although the Chrysler Building was built and designed for the car manufacturer, the corporation did not pay for its construction and never owned it, as Walter Chrysler decided to pay for it himself, so that his children could inherit it.
When the Chrysler Building opened, there were mixed reviews of the building's design, ranging from its being inane and unoriginal to that it was modernist and iconic. Perceptions of the building have evolved into its now being seen as a paragon of the Art Deco architectural style. In the mid-1920s, New York's metropolitan area surpassed London's as the world's most populous metropolitan area and its population exceeded ten million by the early 1930s; the era was characterized by profound technological changes. Consumer goods such as radio and the automobile—whose use grew exponentially in the 1920s—became widespread. In 1927, Walter Chrysler's automotive company, the Chrysler Corporation, became the third-largest car manufacturer in the United States, behind Ford and General Motors; the following year, Chrysler was named Time magazine's "Person of the Year". The economic boom of the 1920s and speculation in the real estate market fostered a wave of new skyscraper projects in New York City; the Chrysler Building was built as part of an ongoing building boom that resulted in the city having the world's tallest building from 1908 to 1974.
Following the end of World War I, European and American architects came to see simplified design as the epitome of the modern era and Art Deco skyscrapers as symbolizing progress and modernity. The 1916 Zoning Resolution restricted the height that street-side exterior walls of New York City buildings could rise before needing to be setback from the street; this led to the construction of Art Deco structures in New York City with significant setbacks, large volumes, striking silhouettes that were elaborately decorated. Art Deco buildings were constructed for only a short period of time; the Chrysler Building project was shaped by these circumstances. The land on which the Chrysler Building stands was donated to The Cooper Union for the Advancement of Science and Art in 1902; the site is a trapezoid with a 201-foot-long frontage on Lexington Avenue. The site bordered the old Boston Post Road, which predated, ran aslant of, the Manhattan street grid established by the Commissioners' Plan of 1811.
As a result, the east side of the building's base is aslant. The Chrysler Building was to be the Reynolds Building, a project of real estate developer and former New York State Senator William H. Reynolds. Prior to his involvement in planning the building, Reynolds was best known for developing Coney Island's Dreamland amusement park; when the amusement park was destroyed by fire in 1911, Reynolds turned his attention to Manhattan real estate, where he set out to build the tallest building in the world. In 1921, Reynolds rented a large plot of land at the corner of Lexington Avenue and 42nd Street with the intention of building a tall building on the site. In 1927, after several years of delays, Reynolds hired the architect William Van Alen to build a forty-story building there. Van Alen was respected in his field for his work on the Albemarle Building at Broadway and 24th Street, designing it in collaboration with his partner H. Craig Severance. Van Alen and Severance complemented each other, with Van Alen being an original, imaginative architect and Severance being a shrewd businessperson who handled the firm's finances.
However, the relationship between them became tense over disagreements on. The breaking point came after a 1924 article, in the Architectural Review, that praised the Albemarle Building's design, which the article attributed to Van Alen, while ignoring Severance's role altogether; the architects' partnership dissolved acrimoniously several months with lawsuits over the firm's clients and assets lasting over a year. This ended up being decisive for the design of the future Chrysler Building, since Severance's more traditional architectural style would otherwise have restrained Van Alen's more modern outlook. By February 2, 1928, the proposed building's height had been increased to 54 stories, which would have made it the tallest building in Midtown; the proposal was changed again two weeks with official plans for a 63-story building. A little more than a week after that, the plan was changed for th
Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, chemical composition, mechanical properties such as strengths, storage practices, etc. are regulated by standards in most industrialized countries. Most structural steel shapes, such as I-beams, have high second moments of area, which means they are stiff in respect to their cross-sectional area and thus can support a high load without excessive sagging; the shapes available are described in many published standards worldwide, a number of specialist and proprietary cross sections are available. I-beam Z-Shape HSS-Shape Angle Structural channel, or C-beam, or C cross-section Tee Rail profile Railway rail Vignoles rail Flanged T rail Grooved rail Bar, a piece of metal, rectangular cross sectioned and long, but not so wide so as to be called a sheet. Rod, a round or square and long piece of metal, see rebar and dowel.
Plate, metal sheets thicker than 1⁄4 in. Open web steel joistWhile many sections are made by hot or cold rolling, others are made by welding together flat or bent plates; the terms angle iron, channel iron, 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, sheet, despite that they are misnomers. In formal writing for metalworking contexts, accurate terms like angle stock, channel stock, sheet are used. Most steels used throughout Europe are specified to comply with the European standard EN 10025. However, many national standards remain in force. Typical grades are described as'S275J2' or'S355K2W'. In these examples,'S' denotes structural rather than engineering steel. Further letters can be used to designate fine grain steel. 1. S275JOH Specification S275JOH is steel grade in EN 10210 standard.
And the most used specification is EN10219 standard, Cold formed welded structural hollow sections of non-alloy and fine grain steels. EN10219-1 specifies 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 and sectional s275 pipe properties are contained in EN 10219-2. 2. S275JOH Steel Pipes manufacture Process The steel manufacturing process shall be at the discretion of the steel producer. S275JOH carbon steel pipes can be made in 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, 460, although some grades are more used than others e.g. in the UK all structural steel is grades S275 and S355. Higher grades are available in tempered material. A set of Euronorms define the shape of a set of standard structural profiles: European I-beam: IPE - Euronorm 19-57 European I-beam: IPN - DIN 1025-1 European flange beams: HE - Euronorm 53-62 European channels: UPN - DIN 1026-1 European cold formed IS IS 800-1 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 two, three, or four numbers. The four-number AISI steel grades used for mechanical engineering and vehicles are a different specification series; the standard used structural steels are: A36 - structural shapes and plate. A53 - structural pipe and tubing. A500 - structural pipe and tubing. A501 - structural pipe and tubing. A529 - structural shapes and plate. A441 - structural shapes and plates. A572 - structural shapes and plates. A618 - structural pipe and tubing. A992 - Possible applications are W or S I-Beams. A913 - Quenched and Self Tempered W shapes. A270 - structural shapes and plates. A243 - structural shapes and plates. A588 - structural shapes and plates. A514 - structural shapes and plates. A517 - boilers and pressure vessels. Eglin steel - Inexpensive aerospace and weaponry items. A668 - Steel Forgings The concept of CE marking for all construction products and steel products is introduced by the Construction Products Directive.
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 u
Concrete Portland cement concrete, is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens over time—most a lime-based cement binder, such as Portland cement, but sometimes with other hydraulic cements, such as a calcium aluminate cement. It is distinguished from other, non-cementitious types of concrete all binding some form of aggregate together, including asphalt concrete with a bitumen binder, used for road surfaces, polymer concretes that use polymers as a binder; when aggregate is mixed together with dry Portland cement and water, the mixture forms a fluid slurry, poured and molded into shape. The cement reacts chemically with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. Additives are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials embedded to provide tensile strength, yielding reinforced concrete.
Famous concrete structures include the Panama Canal and the Roman Pantheon. The earliest large-scale users of concrete technology were the ancient Romans, concrete was used in the Roman Empire; the Colosseum in Rome was built of concrete, the concrete dome of the Pantheon is the world's largest unreinforced concrete dome. Today, large concrete structures are made with reinforced concrete. After the Roman Empire collapsed, use of concrete became rare until the technology was redeveloped in the mid-18th century. Worldwide, concrete has overtaken steel in tonnage of material used; the word concrete comes from the Latin word "concretus", the perfect passive participle of "concrescere", from "con-" and "crescere". Small-scale production of concrete-like materials was pioneered by the Nabatean traders who occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan from the 4th century BC, they discovered the advantages of hydraulic lime, with some self-cementing properties, by 700 BC.
They built kilns to supply mortar for the construction of rubble-wall houses, concrete floors, underground waterproof cisterns. They kept the cisterns secret; some of these structures survive to this day. In the Ancient Egyptian and Roman eras, builders discovered that adding volcanic ash to the mix allowed it to set underwater. German archaeologist Heinrich Schliemann found concrete floors, which were made of lime and pebbles, in the royal palace of Tiryns, which dates to 1400–1200 BC. Lime mortars were used in Greece and Cyprus in 800 BC; the Assyrian Jerwan Aqueduct made use of waterproof concrete. Concrete was used for construction in many ancient structures; the Romans used concrete extensively from 300 BC to a span of more than seven hundred years. During the Roman Empire, Roman concrete was made from quicklime, pozzolana and an aggregate of pumice, its widespread use in many Roman structures, a key event in the history of architecture termed the Roman Architectural Revolution, freed Roman construction from the restrictions of stone and brick materials.
It enabled revolutionary new designs in terms of both structural dimension. Concrete, as the Romans knew it, was a revolutionary material. Laid in the shape of arches and domes, it hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick. Modern tests show that opus caementicium had as much compressive strength as modern Portland-cement concrete. However, due to the absence of reinforcement, its tensile strength was far lower than modern reinforced concrete, its mode of application was different: Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.
The long-term durability of Roman concrete structures has been found to be due to its use of pyroclastic rock and ash, whereby crystallization of strätlingite and the coalescence of calcium–aluminum-silicate–hydrate cementing binder helped give the concrete a greater degree of fracture resistance in seismically active environments. Roman concrete is more resistant to erosion by seawater than modern concrete; the widespread use of concrete in many Roman structures ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon. After the Roman Empire, the use of burned lime and pozzolana was reduced until the technique was all but forgotten between 500 and the 14th century. From the 14th century to the mid-18th century, the use of cement returned; the Canal du Midi was built using concrete in 1670.
The greatest step forward in the modern use
Erector Set is a brand of metal toy construction sets patented by Alfred Carlton Gilbert and first sold by his company, the Mysto Manufacturing Company of New Haven, Connecticut in 1913. In 1916, the company was reorganized as the A. C. Gilbert Company. In 2000, Meccano unified its presence on all continents. Basic Erector parts included various metal beams with regularly-spaced holes for assembly using nuts and bolts. A frequently-promoted feature was the ability to fabricate a strong but lightweight hollow structural girder from four long flat pieces of stamped sheet steel, held together by bolts and nuts. Flat or curved pieces of sheet metal in various shapes and colors could be added to the structural skeleton. Hardened steel rods and screw clamps allowed the construction of hinges and the transmission of mechanical power via rotating parts such as pulleys, gears and levers. Unlike some earlier wooden construction sets, Erector could be used both for static structures and for dynamic structures incorporating mechanical linkages and other moving components.
Modular, standardized construction sets like Erector provided the ability to build a model take it apart and build something else and over again. Both AC-powered electric motors and battery-powered DC motors became available equipped with gears to increase their torque and effective mechanical power. Sets added miniature light bulbs and simple switches to control electrical power. Erector was first envisioned by Alfred Carlton Gilbert in 1911, as he rode the train from New Haven to New York City; this section of track was being converted to electrical power, Gilbert watched as steel girders were erected to carry the power lines, inspiring him to develop the toy. Gilbert was a skilled magician and manufactured magic tricks and magic sets with his existing company the "Mysto Manufacturing Company"; the first Erector set was made there in 1913, called "The Erector / Structural Steel and Electro-Mechanical Builder", labeled as "Educational and Amusing". The toy was first introduced and sold to the public in 1913 at the Toy Fair held at the Broadway Central Hotel in New York City.
Erector became the most popular construction toy in the United States, most because it was the only construction set at the time to contain a motor. In 1914, the name was changed to "The Mysto Erector, The Toy That Resembles Structural Steel". In 1916, the company was reorganized and became the A. C. Gilbert Company; the product was renamed "Gilbert Erector, The Toy Like Structural Steel". In 1924, more changes occurred, as the entire Erector system was overhauled to include over 70 types of parts. Erector was now called "The New Erector, The World’s Greatest Toy". Through 1932, Erector was sold in wooden boxes, but 1933 through 1962 the sets would be sold in colorful boxes made of painted steel. Early boxes were colored green, or blue; as the company grew, the area around the Gilbert factory became known as "Erector Square". A. C. Gilbert died in 1961, the company went into decline, filing for bankruptcy in 1967; the product was redesigned, adding many plastic parts, but the "clunky" looking models failed to compete with the new, more-realistic scale plastic models coming onto the market.
The Gabriel company of Lancaster, Pennsylvania bought the "Erector" name and continued to market the redesigned system. Sales were slow and by the 1980s the trademark Erector was acquired by Ideal Toys and Tyco Toys. In 2000, Meccano unified its presence on all continents; the two brands are now sold under the Meccano brand name. In 2002, a movie based on A. C. Gilbert's life called The Man, it focused on Gilbert's successful appeal to the Council of National Defense to reject a proposal to ban toy production in favor of wartime related materials during World War I. An extensive collection of A. C. Gilbert Company scientific and educational children's toys is housed at the Eli Whitney Museum, in Hamden, Connecticut. Meccano model of a steam shovel excavator powered by a restored 1929 Meccano steam engine, it was built by Chris Els in 2004. With a Meccano set there was a wide range of models. Here are the models for which instructions were given in the largest set of the late 1950s, the "Outfit 10": "Railway Service Crane", "Sports Motor Car", "Coal Tipper", "Cargo Ship", "Double Decker Bus", "Lifting Shovel", "Blocksetting Crane", "Beam Bridge", "Dumper Truck", "Automatic Gantry Crane", "Automatic Snow Loader", "4-4-0 Passenger Locomotive"On top of these there were instruction leaflets available for: "Combine Harvester", "The Eiffel Tower", "Showman’s Traction Engine", "Twin-Cylinder Motor Cycle Engine", "Trench Digger", "Bottom Dump Truck", "Road Surfacing Machine", "Mechanical Loading Shovel"It has been said that the instructions sometimes contained deliberate errors to challenge the ingenuity of its users.
However, those involved in their production maintain such errors were accidental, are no more common than the unintentional errors in other modelling plans. Since this time, enthusiasts such as G. Maurice Morris and MW Models have taken to publishing their own model plans, ranging from small models up to large and complex machines. In 1934, Meccano began to be used in the construction of differential analysers, a type of analogue computer used to solve differential equations which has long since become obsolete. Though invented on paper in the 19th century, the first such machine had only been built in 1931, they would be built by specialist manufacturers, at great cost. For example, in 1947, UCLA in the US install