1.
Bridge
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A bridge is a structure built to span physical obstacles without closing the way underneath such as a body of water, valley, or road, for the purpose of providing passage over the obstacle. There are many different designs that each serve a particular purpose, the Oxford English Dictionary traces the origin of the word bridge to an Old English word brycg, of the same meaning. The word can be traced back to Proto-Indo-European *bʰrēw-. The word for the game of the same name has a different origin. The first bridges made by humans were probably spans of cut wooden logs or planks and eventually stones, using a simple support, some early Americans used trees or bamboo poles to cross small caverns or wells to get from one place to another. Dating to the Greek Bronze Age, it is one of the oldest arch bridges still in existence, several intact arched stone bridges from the Hellenistic era can be found in the Peloponnese. The greatest bridge builders of antiquity were the ancient Romans, the Romans built arch bridges and aqueducts that could stand in conditions that would damage or destroy earlier designs. An example is the Alcántara Bridge, built over the river Tagus, the Romans also used cement, which reduced the variation of strength found in natural stone. One type of cement, called pozzolana, consisted of water, lime, sand, brick and mortar bridges were built after the Roman era, as the technology for cement was lost. In India, the Arthashastra treatise by Kautilya mentions the construction of dams, a Mauryan bridge near Girnar was surveyed by James Princep. The bridge was swept away during a flood, and later repaired by Puspagupta, the use of stronger bridges using plaited bamboo and iron chain was visible in India by about the 4th century. A number of bridges, both for military and commercial purposes, were constructed by the Mughal administration in India and this bridge is also historically significant as it is the worlds oldest open-spandrel stone segmental arch bridge. European segmental arch bridges date back to at least the Alconétar Bridge, rope bridges, a simple type of suspension bridge, were used by the Inca civilization in the Andes mountains of South America, just prior to European colonization in the 16th century. During the 18th century there were innovations in the design of timber bridges by Hans Ulrich Grubenmann, Johannes Grubenmann. The first book on bridge engineering was written by Hubert Gautier in 1716, a major breakthrough in bridge technology came with the erection of the Iron Bridge in Shropshire, England in 1779. It used cast iron for the first time as arches to cross the river Severn, with the Industrial Revolution in the 19th century, truss systems of wrought iron were developed for larger bridges, but iron does not have the tensile strength to support large loads. With the advent of steel, which has a tensile strength, much larger bridges were built. In 1927 welding pioneer Stefan Bryła designed the first welded bridge in the world
2.
Beam bridge
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Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. No moments are transferred throughout the support, hence their structural type is known as simply supported, the simplest beam bridge could be a log, a wood plank, or a stone slab laid across a stream. Bridges designed for modern infrastructure will usually be constructed of steel or reinforced concrete, the concrete elements may be reinforced, prestressed or post-tensioned. Types of construction could include having many beams side by side with a deck across the top of them, the main beams could be I-beams, trusses, or box girders. They could be half-through, or braced across the top to create a through bridge, beam bridges are not limited to a single span. Some viaducts such as the Feiyunjiang Bridge in China have multiple simply supported spans supported by piers and this is opposed to viaducts using continuous spans over the piers. Beam bridges are only used for relatively short distances because, unlike truss bridges. The only supports are provided by piers, the farther apart its supports, the weaker a beam bridge gets. As a result, beam bridges rarely span more than 250 feet and this doesnt mean beam bridges arent used to cross great distances, it only means that a series of beam bridges must be joined together, creating whats known as a continuous span
3.
Cantilever bridge
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A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. Engineers in the nineteenth century understood that a bridge that was continuous across multiple supports would distribute the loads among them and this would result in lower stresses in the girder or truss and meant that longer spans could be built. Several nineteenth century engineers patented continuous bridges with hinge points mid-span, the use of a hinge in the multi-span system presented the advantages of a statically determinate system and of a bridge that could handle differential settlement of the foundations. Engineers could more easily calculate the forces and stresses with a hinge in the girder, heinrich Gerber was one of the engineers to obtain a patent for a hinged girder and is recognized as the first to build one. The Hassfurt Bridge over the Main river in Germany with a span of 124 feet was completed in 1867 and is recognized as the first modern cantilever bridge. The High Bridge of Kentucky by C, the Kentucky River Bridge spanned a gorge that was 275 feet deep and took full advantage of the fact that falsework, or temporary support, is not needed for the main span of a cantilever bridge. The most famous early cantilever bridge is the Forth Bridge and this bridge held the record for longest span in the world for seventeen years, until it was surpassed by the Quebec Bridge. Benjamin Baker illustrated the principles of the suspended span cantilever in the photo on the left. The suspended span, where Kaichi Watanabe sits, is seen in the center, the need to resist compression of the lower chord is seen in the use of wooden poles while the tension of the upper chord is shown by the outstretched arms. The action of the foundations as anchors for the cantilever is visible in the placement of the counterweights. A simple cantilever span is formed by two arms extending from opposite sides of an obstacle to be crossed, meeting at the center. In a common variant, the span, the cantilever arms do not meet in the center, instead. The suspended span may be built off-site and lifted into place, thus, in a bridge built on two foundation piers, there are four cantilever arms, two which span the obstacle, and two anchor arms which extend away from the obstacle. Because of the need for strength at the balanced cantilevers supports. The Commodore Barry Bridge is an example of type of cantilever bridge. Steel truss cantilevers support loads by tension of the upper members, commonly, the structure distributes the tension via the anchor arms to the outermost supports, while the compression is carried to the foundations beneath the central towers. Many truss cantilever bridges use pinned joints and are statically determinate with no members carrying mixed loads. Prestressed concrete balanced cantilever bridges are built using segmental construction
4.
Truss arch bridge
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A truss arch bridge combines the elements of the truss bridge and the arch bridge. The actual resolution of forces will depend upon the design, if no horizontal thrusting forces are generated this becomes an arch-shaped truss, essentially a bent beam – see moon bridge for an example. If horizontal thrust is generated but the apex of the arch is a pin joint, if no hinge exists at the apex, it will normally be a two-hinged arch. In the Iron Bridge shown below, the structure of each frame emulates the kind of structure that previously had made of wood. Such rigid structures were developed in the 20th century as the Vierendeel truss. The Iron Bridge, the first metal bridge of any kind, maria Pia Bridge, Gustave Eiffels pioneering two-hinge arch. Hurricane Deck Bridge, the last remaining truss-type bridge on Lake of the Ozarks in central Missouri, i-35W Mississippi River bridge bridge that collapsed in 2007 in Minneapolis, Minnesota, USA. Navajo Bridge and newer bridge of the general construction, each built as unsupported cantilevers joined with a central pin
5.
Transporter bridge
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A transporter bridge, also known as a ferry bridge or aerial transfer bridge, is a type of movable bridge that carries a segment of roadway across a river. The gondola is slung from a tall span by wires or a metal frame, the design has been used to cross navigable rivers or other bodies of water, where there is a requirement for ship traffic to be able to pass. This has been a type of bridge, with fewer than two dozen built. There are just twelve that continue to be used today, including one converted into a bridge and one designed as, but not yet operating as. The concept of the bridge was invented in 1873 by Charles Smith the manager of an engine works in Hartlepool. He called it a bridge ferry and unsuccessfully presented his ideas to councils in Hartlepool, Middlesbrough, the first transporter bridge, Vizcaya Bridge was built between Las Arenas and Portugalete, Spain, in 1893. The design from Alberto Palacio inspired others to similar structures. The idea came about in locations where it was seen as impractical to build long approach ramps that would be required to reach a high span, because transporter bridges can carry only a limited load, the idea was little used after the rise of the automobile. The first such built in France, the 1898 Rouen bridge crossing the Seine, was destroyed by the French army to slow down German troops in World War II. Transporter bridges were popular in France, where five were erected, the Newport Transporter Bridge was built in 1906 across the River Usk in Newport. Because the river banks are low at the crossing point a traditional bridge would need a very long approach ramp. The Newport bridge was a Ferdinand Arnodin design, the Widnes-Runcorn Transporter Bridge, demolished in the early 1960s, was the first of its type in Britain, and the largest ever built. In the United States, two bridges were built. The first was the Aerial Bridge built in Duluth, Minnesota in 1905, the transporter design was used for about 25 years before the structure was reconfigured to lift a central span in 1930. The second American transporter bridge was different from other designs and partially resembled gondola lifts used in mountainous regions, the Sky Ride was part of the 1933–34 Chicago Worlds Fair, it was taken down after standing for just two years. However, it was the longest bridge of this type built at the time. Two historic transporter bridges survived in Germany, a unique example is the bridge at Rendsburg, from 1913 which is two bridges in one, A railroad link crosses high above on the top span, and the suspended ferry carries traffic on the valley floor. The bridge at Osten is four years older and was the first transporter bridge in Germany, the Soviet Union built the longest known transporter bridge in Stalingrad in 1955
6.
Lattice truss bridge
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A lattice bridge is a form of truss bridge that uses a large number of small and closely spaced diagonal elements that form a lattice. It was patented by architect Ithiel Town in 1820 and 1835 as Towns lattice truss, the individual elements are more easily handled by the construction workers, but the bridge also requires substantial support during construction. A simple lattice truss will transform the applied loads into a thrust, the Belfast truss is a cross between the Towns lattice truss and the bowstring truss. It was developed in Ireland as a wide-span shallow rise roof truss for industrial structures, mcTear & Co of Belfast, Ireland began fabricating these trusses in wood starting around 1866. By 1899, spans of 24 meters had been achieved, and in the 20th century, shipyards and this was built for the New York Central Railroad in 1859. org/WatsonMillBridge
7.
Pedestrian
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A pedestrian is a person traveling on foot, whether walking or running. In some communities, those traveling using tiny wheels such as skates, skateboards. In modern times, the term refers to someone walking on a road or pavement. Walking has always been the means of human locomotion. The first humans to migrate from Africa, about 60,000 years ago and they walked along the coast of India to reach Australia. They walked across Asia to reach the Americas, and from Central Asia into Europe, during the 18th and 19th centuries, pedestrianism was a popular spectator sport just as equestrianism still is in places such as Great Britain and the United States. One of the most famous pedestrians of that period was Captain Robert Barclay Allardice, known as The Celebrated Pedestrian and his most impressive feat was to walk 1 mile every hour for 1000 hours, which he achieved between 1 June and 12 July 1809. This feat captured many peoples imagination, and around 10,000 people came to watch over the course of the event. During the rest of the 19th century, many tried to repeat this feat, including Ada Anderson who developed it further. Since the 20th century, interest in walking as a sport has dropped, racewalking is still an Olympic sport, but fails to catch public attention as it did. However major walking feats are still performed, such as the Lands End to John o Groats walk in the United Kingdom, and these feats are often tied to charitable fundraising and are undertaken by celebrities such as Sir Jimmy Savile and Ian Botham as well as by others. Regular walking is important both for health and for the natural environment. Frequent exercise such as walking tends to reduce the chance of obesity, general availability of public transportation encourages walking, as it will not, in most cases, take one directly to ones destination. Roads often have a designated footpath for pedestrian traffic, called the sidewalk in North American English, the pavement in British English, and the footpath in Australian and New Zealand English. There are also not associated with a road, these include urban short cuts and also rural paths used mainly by ramblers, hikers. Footpaths in mountainous or forested areas may also be called trails, pedestrians share some footpaths with horses and bicycles, these paths may be known as bridleways. Other byways used by walkers are also accessible to vehicles, there are also many roads with no footpath. Some modern towns are designed with the network of sidewalks and cycle paths almost entirely separate from the road network, the term trail is also used by the authorities in some countries to mean any footpath that is not attached to a road or street
8.
Pipeline transport
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Pipeline transport is the transportation of goods or material through a pipe. The latest data, in 2014, gives a total of less than 2,175,000 miles of pipeline in 120 countries of the world. The United States had 65%, Russia had 8%, and Canada had 3%, Pipeline and Gas Journal’s worldwide survey figures indicate that 118,623 miles of pipelines are planned and under construction. Of these,88,976 miles represent projects in the planning, Liquids and gases are transported in pipelines and any chemically stable substance can be sent through a pipeline. Pipelines exist for the transport of crude and refined petroleum, fuels - such as oil, natural gas and biofuels - and other fluids including sewage, slurry, water, pneumatic tubes using compressed air can be used to transport solid capsules. Oil pipelines are made from steel or plastic tubes which are usually buried, the oil is moved through the pipelines by pump stations along the pipeline. Natural gas are lightly pressurised into liquids known as Natural Gas Liquids, Natural gas pipelines are constructed of carbon steel. Highly toxic ammonia is theoretically the most dangerous substance to be transported through long-distance pipelines, hydrogen pipeline transport is the transportation of hydrogen through a pipe. District heating or teleheating systems use a network of insulated pipes which transport heated water, pipelines conveying flammable or explosive material, such as natural gas or oil, pose special safety concerns and there have been various accidents. Pipelines can be the target of vandalism, sabotage, or even terrorist attacks, in war, pipelines are often the target of military attacks. It is uncertain when the first crude oil pipeline was built, pipelines are generally the most economical way to transport large quantities of oil, refined oil products or natural gas over land. Natural gas are lightly pressurized into liquids knows as Natural Gas Liquids, small NGL processing facilities can be located in oil fields so the butane and propane liquid under light pressure of 125 pounds per square inch, can be shipped by rail, truck or pipeline. Propane can be used as a fuel in oil fields to heat various facilities used by the oil drillers or equipment and trucks used in the oil patch. EG, Propane will convert from a gas to a liquid under pressure,100 psi, give or take depending on temperature. Pipelines and rail cars use about double that pressure to pump at 250 psi, the distance to ship propane to markets is much shorter, as thousands of natural-gas processing plants are located in or near oil fields. Compared to shipping by railroad, pipelines have lower cost per unit, pipelines are preferable to transportation by truck for a number of reasons. Employment on completed pipelines represents only 1% of that of the trucking industry and this allows the Bakken Basin and Three Forks oil producers to get higher negotiated prices for their oil because they will not be restricted to just one wholesale market in the US. The distance from the biggest oil patch in North Dakota, is Williston, North Dakota, only about 85 miles or 137 kilometers to the Canada–US border, mutual funds and joint ventures are big investors in new oil and gas pipelines
9.
Car
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A car is a wheeled, self-powered motor vehicle used for transportation and a product of the automotive industry. The year 1886 is regarded as the year of the modern car. In that year, German inventor Karl Benz built the Benz Patent-Motorwagen, cars did not become widely available until the early 20th century. One of the first cars that was accessible to the masses was the 1908 Model T, an American car manufactured by the Ford Motor Company. Cars were rapidly adopted in the United States of America, where they replaced animal-drawn carriages and carts, cars are equipped with controls used for driving, parking, passenger comfort and safety, and controlling a variety of lights. Over the decades, additional features and controls have been added to vehicles, examples include rear reversing cameras, air conditioning, navigation systems, and in car entertainment. Most cars in use in the 2010s are propelled by a combustion engine. Both fuels cause air pollution and are blamed for contributing to climate change. Vehicles using alternative fuels such as ethanol flexible-fuel vehicles and natural gas vehicles are also gaining popularity in some countries, electric cars, which were invented early in the history of the car, began to become commercially available in 2008. There are costs and benefits to car use, the costs of car usage include the cost of, acquiring the vehicle, interest payments, repairs and auto maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance. The costs to society of car use include, maintaining roads, land use, road congestion, air pollution, public health, health care, road traffic accidents are the largest cause of injury-related deaths worldwide. The benefits may include transportation, mobility, independence. The ability for humans to move flexibly from place to place has far-reaching implications for the nature of societies and it was estimated in 2010 that the number of cars had risen to over 1 billion vehicles, up from the 500 million of 1986. The numbers are increasing rapidly, especially in China, India, the word car is believed to originate from the Latin word carrus or carrum, or the Middle English word carre. In turn, these originated from the Gaulish word karros, the Gaulish language was a branch of the Brythoic language which also used the word Karr, the Brythonig language evolved into Welsh where Car llusg and car rhyfel still survive. It originally referred to any wheeled vehicle, such as a cart, carriage. Motor car is attested from 1895, and is the formal name for cars in British English. Autocar is a variant that is attested from 1895
10.
Truck
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A truck is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, smaller varieties may be similar to some automobiles. Commercial trucks can be large and powerful, and may be configured to mount specialized equipment, such as in the case of fire trucks and concrete mixers. Modern trucks are powered by diesel engines, although small to medium size trucks with gasoline engines exist in the US. In the European Union, vehicles with a gross mass of up to 3.5 t are known as light commercial vehicles. Trucks and cars have an ancestor, the steam-powered fardier Nicolas-Joseph Cugnot built in 1769. However, steam wagons were not common until the mid-1800s, the roads of the time, built for horse and carriages, limited these vehicles to very short hauls, usually from a factory to the nearest railway station. The first semi-trailer appeared in 1881, towed by a tractor manufactured by De Dion-Bouton. In 1895 Karl Benz designed and built the first truck in history using the internal combustion engine, later that year some of Benzs trucks were modified to become the first bus by the Netphener, the first motorbus company in history. A year later, in 1896, another internal combustion engine truck was built by Gottlieb Daimler, other companies, such as Peugeot, Renault and Büssing, also built their own versions. The first truck in the United States was built by Autocar in 1899 and was available with optional 5 or 8 horsepower motors, trucks of the era mostly used two-cylinder engines and had a carrying capacity of 3,300 to 4,400 lb. In 1904,700 heavy trucks were built in the United States,1000 in 1907,6000 in 1910, after World War I, several advances were made, pneumatic tires replaced the previously common full rubber versions. Electric starters, power brakes,4,6, and 8 cylinder engines, closed cabs, the first modern semi-trailer trucks also appeared. Touring car builders such as Ford and Renault entered the heavy truck market, although it had been invented in 1890, the diesel engine was not common in trucks in Europe until the 1930s. In the United States, it took longer for diesel engines to be accepted. The word truck might come from a back-formation of truckle, meaning small wheel or pulley, from Middle English trokell, another possible source is the Latin trochus, meaning iron hoop. In turn, both sources emanate from the Greek trokhos, meaning wheel, from trekhein, the first known usage of truck was in 1611, when it referred to the small strong wheels on ships cannon carriages. In its extended usage it came to refer to carts for carrying heavy loads and its expanded application to motor-powered load carrier has been in usage since 1930, shortened from motor truck, which dates back to 1901
11.
Light rail
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Light rail, light rail transit or fast tram is urban public transport using rolling stock similar to a tramway, but operating at a higher capacity, and often on an exclusive right-of-way. A few light rail networks tend to have closer to rapid transit or even commuter rail. Other light rail networks are tram-like in nature and partially operate on streets, Light rail systems are found throughout the world, on all inhabited continents. They have been popular in recent years due to their lower capital costs. The term light rail was coined in 1972 by the U. S, Urban Mass Transportation Administration to describe new streetcar transformations that were taking place in Europe and the United States. In Germany the term Stadtbahn was used to describe the concept, and many in UMTA wanted to adopt the direct translation, however, UMTA finally adopted the term light rail instead. Light in this context is used in the sense of intended for light loads and fast movement, the infrastructure investment is also usually lighter than would be found for a heavy rail system. The Transportation Research Board defined light rail in 1977 as a mode of urban transportation utilizing predominantly reserved, electrically propelled rail vehicles operate singly or in trains. LRT provides a range of passenger capabilities and performance characteristics at moderate costs. Light rail is a generic international English phrase for these types of rail systems, the use of the generic term light rail avoids some serious incompatibilities between British and American English. The word trolley is used as a synonym for streetcar in the United States. A further difference arose because, while Britain abandoned all of its trams except Blackpool after World War II, when these cities upgraded to new technology, they called it light rail to differentiate it from their existing streetcars since some continued to operate both the old and new systems. Conventional rail technologies including high-speed, freight, commuter/regional, and metro/subway/elevated urban transit systems are considered heavy rail, people movers and personal rapid transit are even lighter, at least in terms of capacity. Monorail is a technology that has been more successful in specialized services than in a commuter transit role. Due to varying definitions, it is hard to distinguish between what is called light rail, and other forms of urban and commuter rail, a system described as light rail in one city may be considered to be a streetcar or tram system in another. Conversely, some lines that are called light rail are in very similar to rapid transit, in recent years. Some light rail systems, such as Sprinter, bear little similarity to urban rail, in the United States, light rail has become a catch-all term to describe a wide variety of passenger rail systems. There is a significant difference in cost between these different classes of light rail transit, tram-like systems are often less expensive than metro-like systems by a factor of two or more
12.
Passenger rail terminology
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It uses passenger railcars operating singly or in multiple unit trains on fixed rails. It operates on separate rights-of-way from which all other vehicular and foot traffic are excluded and it uses sophisticated signaling systems, and high platform loading. Originally, the rapid transit was used in the 1800s to describe new forms of quick urban public transportation that had a right-of-way separated from street traffic. This set rapid transit apart from horsecars, trams, streetcars, omnibuses, though the term was almost always used to describe rail transportation, other forms of transit were sometimes described by their proponents as rapid transit, including local ferries in some cases. The term bus rapid transit has recently come into use to describe bus lines with features to speed their operation and these usually have more characteristics of light rail than rapid transit. They are consequently designed for operations in tunnel, viaducts or on surface level, in different parts of the world Metro systems are also known as the underground, the subway or the tube. Rail systems with specific construction issues operating on a segregated guideway are also treated as Metros as long as they are designated as part of the public transport network. ”Metropolitan railways are used for high capacity public transportation. They can operate in trains of up to 10 cars, carrying 1800 passengers or more, in Germany, the terms U-Bahn and S-Bahn are used. Some metro systems run on rubber tires but are based on the same principles as steel wheel systems. Subway used in a transit sense refers to either a rapid transit system using heavy rail or a light system that goes underground. The term may only to the underground parts of the system. Some lines described as subway use light rail equipment, notably, Bostons Green Line and the Newark City Subway, each about half underground, originated from fully surface streetcar lines. Sometimes the term is qualified, such as in Philadelphia, where trolleys operate in a subway for part of their route. In some cities where subway is used, it refers to the system, in others. Historic posters referred to Chicagos Red & Blue lines as the subway lines, interestingly, when the Boston subway was originally built, the subway label was only used for sections into which streetcars operated, and the rapid transit sections were called tunnels. Bus subways are uncommon but do exist, though in cases the non-underground portions of route are not called subways. Bus subways are built to provide an exclusive right-of-way for bus rapid transit lines. These are usually called by the bus rapid transit
13.
Lumber
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Lumber, or timber is wood that has been processed into beams and planks, a stage in the process of wood production. Lumber may also refer to currently un-needed furniture, as in Lumber room, or an awkward gait, ultimately derived from the look of unfashionable, Lumber may be supplied either rough-sawn, or surfaced on one or more of its faces. Besides pulpwood, rough lumber is the raw material for furniture-making and it is available in many species, usually hardwoods, but it is also readily available in softwoods, such as white pine and red pine, because of their low cost. Lumber is mainly used for structural purposes but has other uses as well. It is classified more commonly as a softwood than as a hardwood, in Australia, Ireland, New Zealand and Britain, the term timber describes sawn wood products, such as floor boards. In the United States and Canada, generally timber describes standing or felled trees, before they are milled into boards, Timber there also describes sawn lumber not less than 5 inches in its smallest dimension. The latter includes the often partly finished lumber used in timber-frame construction, remanufactured lumber is the result of secondary or tertiary processing/cutting of previously milled lumber. Specifically, it is cut for industrial or wood-packaging use. Lumber is cut by ripsaw or resaw to create dimensions that are not usually processed by a primary sawmill, resawing is the splitting of 1-inch through 12-inch hardwood or softwood lumber into two or more thinner pieces of full-length boards. For example, splitting a ten-foot 2×4 into two ten-foot 1×4s is considered resawing, structural lumber may also be produced from recycled plastic and new plastic stock. Its introduction has been opposed by the forestry industry. Blending fiberglass in plastic lumber enhances its strength, durability, logs are converted into timber by being sawn, hewn, or split. Sawing with a rip saw is the most common method, because sawing allows logs of lower quality, with grain and large knots. There are various types of sawing, Plain sawn —A log sawn through without adjusting the position of the log, quarter sawn and rift sawn—These terms have been confused in history but generally mean lumber sawn so the annual rings are reasonably perpendicular to the sides of the lumber. Boxed heart—The pith remains within the piece with some allowance for exposure, heart center—the center core of a log. Free of heart center —A side-cut timber without any pith, free of knots —No knots are present. Dimensional lumber is lumber that is cut to standardized width and depth, carpenters extensively use dimensional lumber in framing wooden buildings. Common sizes include 2×4, 2×6, and 4×4, the length of a board is usually specified separately from the width and depth
14.
Iron
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Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series and it is by mass the most common element on Earth, forming much of Earths outer and inner core. It is the fourth most common element in the Earths crust, like the other group 8 elements, ruthenium and osmium, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen, fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. Unlike the metals that form passivating oxide layers, iron oxides occupy more volume than the metal and thus flake off, Iron metal has been used since ancient times, although copper alloys, which have lower melting temperatures, were used even earlier in human history. Pure iron is soft, but is unobtainable by smelting because it is significantly hardened and strengthened by impurities, in particular carbon. A certain proportion of carbon steel, which may be up to 1000 times harder than pure iron. Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and iron alloys formed with metals are by far the most common industrial metals because they have a great range of desirable properties. Iron chemical compounds have many uses, Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. Iron forms binary compounds with the halogens and the chalcogens, among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology, forming complexes with oxygen in hemoglobin and myoglobin. Iron is also the metal at the site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants. A human male of average height has about 4 grams of iron in his body and this iron is distributed throughout the body in hemoglobin, tissues, muscles, bone marrow, blood proteins, enzymes, ferritin, hemosiderin, and transport in plasma. The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, Rockwell test, the data on iron is so consistent that it is often used to calibrate measurements or to compare tests. An increase in the content will cause a significant increase in the hardness. Maximum hardness of 65 Rc is achieved with a 0. 6% carbon content, because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. Because of its significance for planetary cores, the properties of iron at high pressures and temperatures have also been studied extensively
15.
Steel
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Steel is an alloy of iron and other elements, primarily carbon, that is widely used in construction and other applications because of its high tensile strength and low cost. Steels base metal is iron, which is able to take on two forms, body centered cubic and face centered cubic, depending on its temperature. It is the interaction of those allotropes with the elements, primarily carbon. In the body-centred cubic arrangement, there is an atom in the centre of each cube. Carbon, other elements, and inclusions within iron act as hardening agents that prevent the movement of dislocations that otherwise occur in the lattices of iron atoms. The carbon in steel alloys may contribute up to 2. 1% of its weight. Steels strength compared to pure iron is possible at the expense of irons ductility. With the invention of the Bessemer process in the mid-19th century and this was followed by Siemens-Martin process and then Gilchrist-Thomas process that refined the quality of steel. With their introductions, mild steel replaced wrought iron, further refinements in the process, such as basic oxygen steelmaking, largely replaced earlier methods by further lowering the cost of production and increasing the quality of the product. Today, steel is one of the most common materials in the world and it is a major component in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons. Modern steel is generally identified by various grades defined by assorted standards organizations, the noun steel originates from the Proto-Germanic adjective stakhlijan, which is related to stakhla. The carbon content of steel is between 0. 002% and 2. 1% by weight for plain iron–carbon alloys and these values vary depending on alloying elements such as manganese, chromium, nickel, iron, tungsten, carbon and so on. Basically, steel is an alloy that does not undergo eutectic reaction. In contrast, cast iron does undergo eutectic reaction, too little carbon content leaves iron quite soft, ductile, and weak. Carbon contents higher than those of steel make an alloy, commonly called pig iron, while iron alloyed with carbon is called carbon steel, 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 are important in steel, phosphorus, sulfur, silicon, and traces of oxygen, nitrogen, and copper. Alloys with a higher than 2. 1% carbon content, depending on other element content, 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
16.
Reinforced concrete
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The reinforcement is usually, though not necessarily, steel reinforcing bars and is usually embedded passively in the concrete before the concrete sets. Reinforcing schemes are designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made of steel, Reinforced concrete may also be permanently stressed, so as to improve the behaviour of the final structure under working loads. In the United States, the most common methods of doing this are known as pre-tensioning and post-tensioning, durability in the concrete environment, irrespective of corrosion or sustained stress for example. François Coignet was a French industrialist of the century, a pioneer in the development of structural. Coignet was the first to use iron-reinforced concrete as a technique for constructing building structures, in 1853 Coignet built the first iron reinforced concrete structure, a four story house at 72 rue Charles Michels in the suburbs of Paris. Coignets descriptions of reinforcing concrete suggests that he did not do it for means of adding strength to the concrete, in 1854, English builder William B. Wilkinson reinforced the concrete roof and floors in the two-storey house he was constructing. His positioning of the reinforcement demonstrated that, unlike his predecessors, in 1877, Monier was granted another patent for a more advanced technique of reinforcing concrete columns and girders with iron rods placed in a grid pattern. Though Monier undoubtedly knew reinforcing concrete would improve its inner cohesion, before 1877 the use of concrete construction, though dating back to the Roman Empire and reintroduced in the mid to late 1800s, was not yet a proven scientific technology. His work played a role in the evolution of concrete construction as a proven. Without Hyatts work, more dangerous trial and error methods would have largely depended on for the advancement in the technology. G. A. Wayss was a German civil engineer and a pioneer of the iron, in 1879 Wayss bought the German rights to Moniers patents and in 1884 started the first commercial use for reinforced concrete in his firm Wayss & Freytag. Up until the 1890s Wayss and his firm greatly contributed to the advancement of Moniers system of reinforcing, ernest L. Ransome was an English-born engineer and early innovator of the reinforced concrete techniques in the end of the 19th century. With the knowledge of reinforced concrete developed during the previous 50 years, ransomes key innovation was to twist the reinforcing steel bar improving bonding with the concrete. Gaining increasing fame from his concrete constructed buildings Ransome was able to build two of the first reinforced concrete bridges in North America, one of the first concrete buildings constructed in the United States, was a private home, designed by William Ward in 1871. The home was designed to be fireproof for his wife, one of the first skyscrapers made with reinforced concrete was the 16-storey Ingalls Building in Cincinnati, constructed in 1904. Many different types of structures and components of structures can be built using reinforced concrete including slabs, walls, beams, columns, foundations, frames, Reinforced concrete can be classified as precast or cast-in-place concrete. Designing and implementing the most efficient floor system is key to creating optimal building structures, small changes in the design of a floor system can have significant impact on material costs, construction schedule, ultimate strength, operating costs, occupancy levels and end use of a building
17.
Prestressed concrete
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Prestressed concrete is a concrete construction material which is placed under compression prior to it supporting any applied loads. A more technical definition is Structural concrete in which stresses have been introduced to reduce potential tensile stresses in the concrete resulting from loads. This compression is produced by the tensioning of high-strength tendons located within or adjacent to the concrete volume, tendons may consist of single wires, multi-wire strands or threaded bars, and are most commonly made from high-tensile steels, carbon fibre or aramid fibre. This can result in improved structural capacity and/or serviceability compared to reinforced concrete in many situations. Typical applications range through high-rise buildings, residential slabs, foundation systems, bridge and dam structures, silos and tanks, industrial pavements, first used in the late-nineteenth century, prestressed concrete has developed to encompass a wide range of technologies. Tensioning of the tendons may be undertaken either before or after the concrete itself is cast, tendons may be located either within the concrete volume, or wholly outside of it. Whereas pre-tensioned concrete by definition uses tendons directly bonded to the concrete, pre-tensioned concrete is a variant of prestressed concrete where the tendons are tensioned prior to the concrete being cast. Pre-tensioning is a common technique, where the resulting concrete element is manufactured remotely from the final structure location. It requires strong, stable end-anchorage points between which the tendons are stretched and these anchorages form the ends of a casting bed which may be many times the length of the concrete element being fabricated. Higher bond strength in early-age concrete allows more economical fabrication as it speeds production, to promote this, pre-tensioned tendons are usually composed of isolated single wires or strands, as this provides a greater surface area for bond action than bundled strand tendons. Unlike those of post-tensioned concrete, the tendons of pre-tensioned concrete elements generally form straight lines between end-anchorages, where profiled or harped tendons are required, one or more intermediate deviators are located between the ends of the tendon to hold the tendon to the desired non-linear alignment during tensioning. Such deviators usually act against substantial forces, and hence require a robust casting bed foundation system, pre-tensioned concrete is most commonly used for the fabrication of structural beams, floor slabs, hollow-core planks, balconies, lintels, driven piles, water tanks and concrete pipes. Post-tensioned concrete is a variant of prestressed concrete where the tendons are tensioned after the concrete structure has been cast. The tendons are not placed in contact with the concrete. At each end of a tendon is an anchorage assembly firmly fixed to the surrounding concrete, once the concrete has been cast and set, the tendons are tensioned by pulling the tendon ends through the anchorages while pressing against the concrete. The large forces required to tension the tendons result in a significant permanent compression being applied to the once the tendon is locked-off at the anchorage. Casting the tendon ducts/sleeves into the concrete before any tensioning occurs allows them to be profiled to any desired shape including incorporating vertical and/or horizontal curvature. Bonded post-tensioning has prestressing tendons permanently bonded to the concrete by the in situ grouting of their encapsulating ducting following tendon tensioning
18.
Moveable bridge
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A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. An advantage of making bridges moveable is the lower cost, due to the absence of high piers, the principal disadvantage is that the traffic on the bridge must be halted when it is opened for passages. For seldom-used railroad bridges over busy channels, the bridge may be open and then closed for train passages. For small bridges, bridge movement may be enabled without the need for an engine, some bridges are operated by the users, especially those with a boat, others by a bridgeman, a few remotely using video-cameras and loudspeakers. Generally, the bridges are powered by motors, whether operating winches, gearing. While moveable bridges in their entirety may be long, the length of the moveable portion is restricted by engineering. There are often traffic lights for the road and water traffic, ninety-nine were killed and 100 were injured. Four crewmen, including the engineer and fireman, and 44 passengers died by drowning, september 22,1993 – Mobile, Alabama, US, In heavy fog and low visibility, a disoriented towboat pilot made a wrong turn and entered an un-navigable waterway. The rails kinked but did not break, so no fault was indicated for approaching trains, approximately 8 minutes later, an Amtrak train carrying 220 passengers derailed at the kinked portion of the rails, killing 47 and injuring 103 more. November 23,1996 – Kearny, New Jersey, US, An Amtrak passenger and mail train derailed crossing the Portal Bridge over the Hackensack River. Moveable Bridges in the British Isles NSW moveable bridges
19.
Falsework
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This usage is specifically called centering. The British Standards of practice for falsework, BS5975,1982, until the turn of the 20th century almost all falsework was constructed from timber. To compensate for shortages in different regions and to rationalize labor and material usage. The major developments include the design of devices, transitions to other spanning beams such as steel pipes or profiles or reusable timber beams. During the same period many different scaffolding systems were being developed around the world and these consisted of welded frames that could be slotted or clipped together to form access or support towers. The reduction in time and complexity led to reduced labor costs. Further developments have made scaffolding systems even easier to use, stronger systems have been introduced that either incorporate horizontal restraints at more levels or use stronger tubes or connections. Materials from which falsework systems are manufactured have also diversified from traditional steel, in the UK, BS5975 gives recommendations for the design and use of falsework on construction sites. It was first introduced by the British Standards Institute in March 1982 and was revised in March 1996. The code is currently under revision again, a copy was released in late 2007. Fabrication, Metalworkers fabricate a falsework section from pipe and beams, erection, A section is lifted to a vertical position with the assistance of two forklift operators. Placement, The section is guided into position by a ground crew, completed Falsework, Decking and some formwork has been added. When the supports are complete, wood beams and plywood or reusable metal forms will be placed, reinforcing and tenon conduits added, after curing and any tenon tensioning, wedges will be removed and forms and falsework disassembled. A certain type of bridge, the suspension bridge, must be supported during construction
20.
Superstructure
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A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of structures such as buildings, bridges. The word superstructure is a combination of the Latin prefix, super with the Latin stem word, in order to improve the response during earthquakes of buildings and bridges, the superstructure might be separated from its foundation by various civil engineering mechanisms or machinery. All together, these implement the system of protection called base isolation. As stated above, superstructure consists of the parts of the ship or a boat, including sailboats, fishing boats, passenger ships, and submarines and this does not usually include its masts or any armament turrets. Note that in times, turrets do not always carry naval artillery. The size of a watercrafts superstructure can have implications in the performance of ships and boats, since these structures can alter their structural rigidity, their displacements. These can be detrimental to any vessels performance if they are taken into consideration incorrectly, the height and the weight of superstructure on board a ship or a boat also affects the amount of freeboard that such a vessel requires along its sides, down to her waterline. In broad terms, the more and heavier superstructure that a ship possesses, on a bridge, the portion of the structure that is the span and directly receives the live load is referred to as the superstructure. In contrast, the abutment, piers, and other structures are called the substructure
21.
Truss
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In engineering, a truss is a structure that consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object. A two-force member is a component where force is applied to only two points. In this typical context, external forces and reactions to those forces are considered to act only at the nodes and result in forces in the members that are either tensile or compressive. For straight members, moments are explicitly excluded because, and only because, all the joints in a truss are treated as revolutes, as is necessary for the links to be two-force members. A planar truss is one all members and nodes lie within a two dimensional plane, while a space truss has members and nodes that extend into three dimensions. The top beams in a truss are called top chords and are typically in compression, the beams are called bottom chords. The interior beams are called webs, and the areas inside the webs are called panels, Truss derives from the Old French word trousse, from around 1200, which means collection of things bound together. The term truss has often used to describe any assembly of members such as a cruck frame or a couple of rafters. One engineering definition is, A truss is a single plane framework of individual structural member connected at their ends of forms a series of triangle to span a large distance, a truss consists of typically straight members connected at joints, traditionally termed panel points. Trusses are typically composed of triangles because of the stability of that shape. A triangle is the simplest geometric figure that will not change shape when the lengths of the sides are fixed, in comparison, both the angles and the lengths of a four-sided figure must be fixed for it to retain its shape. The joint at which a truss is designed to be supported is commonly referred to as the Munter Point, the simplest form of a truss is one single triangle. This type of truss is seen in a roof consisting of rafters and a ceiling joist. Because of the stability of this shape and the methods of used to calculate the forces within it. The traditional diamond-shape bicycle frame, which utilizes two conjoined triangles, is an example of a simple truss, a planar truss lies in a single plane. Planar trusses are used in parallel to form roofs and bridges. The depth of a truss, or the height between the upper and lower chords, is what makes it an efficient structural form, a solid girder or beam of equal strength would have substantial weight and material cost as compared to a truss. For a given span, a deeper truss will require less material in the chords, an optimum depth of the truss will maximize the efficiency
22.
Tension (physics)
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Tension is the opposite of compression. At the atomic level, when atoms or molecules are pulled apart each other and gain potential energy with a restoring force still existing. Each end of a string or rod under such tension will pull on the object it is attached to, to restore the string/rod to its relaxed length. In physics, tension, as a force, as an action-reaction pair of forces. The ends of a string or other object transmitting tension will exert forces on the objects to which the string or rod is connected and these forces due to tension are also called passive forces. Tension in a string is a scalar quantity. A string or rope is often idealized as one dimension, having length but being massless with zero cross section. If there are no bends in the string, as occur with vibrations or pulleys, then tension is a constant along the string, by Newtons Third Law, these are the same forces exerted on the ends of the string by the objects to which the ends are attached. If the string curves around one or more pulleys, it still have constant tension along its length in the idealized situation that the pulleys are massless and frictionless. A vibrating string vibrates with a set of frequencies that depend on the strings tension and these frequencies can be derived from Newtons laws of motion. Each microscopic segment of the string pulls on and is pulled upon by its neighboring segments, tension = τ where x is the position along the string. If the string has curvature, then the two pulls on a segment by its two neighbors will not add to zero, and there will be a net force on that segment of the string, causing an acceleration. With solutions that include the various harmonics on a stringed instrument, tension is also used to describe the force exerted by the ends of a three-dimensional, continuous material such as a rod or truss member. Such a rod elongates under tension, a system is in equilibrium when the sum of all forces is zero. ∑ F → =0 For example, consider a system consisting of an object that is being lowered vertically by a string with tension, T, at a constant velocity. ∑ F → = T → + m g → =0 A system has a net force when a force is exerted on it. Acceleration and net force always exist together, ∑ F → ≠0 For example, consider the same system as above but suppose the object is now being lowered with an increasing velocity downwards therefore there exists a net force somewhere in the system. In this case, negative acceleration would indicate that | m g | > | T |
23.
Compression (physics)
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It is contrasted with tension or traction, the application of balanced outward forces, and with shearing forces, directed so as to displace layers of the material parallel to each other. The compressive strength of materials and structures is an important engineering consideration, in uniaxial compression the forces are directed along one direction only, so that they act towards decreasing the objects length along that direction. If the stress vector itself is opposite to x, the material is said to be under compression or pure compressive stress along x. In a solid, the amount of compression depends on the direction x. If the stress vector is purely compressive and has the same magnitude for all directions and this is the only type of static compression that liquids and gases can bear. In a mechanical longitudinal wave, or compression wave, the medium is displaced in the waves direction, when put under compression, every material will suffer some deformation, even if imperceptible, that causes the average relative positions of its atoms and molecules to change. The deformation may be permanent, or may be reversed when the compression forces disappear, in the latter case, the deformation gives rise to reaction forces that oppose the compression forces, and may eventually balance them. Liquids and gases cannot bear steady uniaxial or biaxial compression, they will deform promptly and permanently, however they can bear isotropic compression, and may be compressed in other ways momentarily, for instance in a sound wave. The deformation may not be uniform and may not be aligned with the compression forces, what happens in the directions where there is no compression depends on the material. Most materials will expand in those directions, but some special materials will remain unchanged or even contract, by inducing compression, mechanical properties such as compressive strength or modulus of elasticity, can be measured. Compression machines range from small table top systems to ones with over 53 MN capacity. Gases are often stored and shipped in highly compressed form, to save space, slightly compressed air or other gases are also used to fill balloons, rubber boats, and other inflatable structures. Compressed liquids are used in equipment and in fracking. In internal combustion engines the explosive mixture gets compressed before it is ignited, in the Otto cycle, for instance, the second stroke of the piston effects the compression of the charge which has been drawn into the cylinder by the first forward stroke. This compression, moreover, obviates the shock which would otherwise be caused by the admission of the steam for the return stroke. Buckling Container compression test Compression member Compressive strength Longitudinal wave P-wave Rarefaction Strength of materials
24.
Newton's laws of motion
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Newtons laws of motion are three physical laws that, together, laid the foundation for classical mechanics. They describe the relationship between a body and the forces acting upon it, and its motion in response to those forces. More precisely, the first law defines the force qualitatively, the second law offers a measure of the force. These three laws have been expressed in different ways, over nearly three centuries, and can be summarised as follows. The three laws of motion were first compiled by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica, Newton used them to explain and investigate the motion of many physical objects and systems. For example, in the volume of the text, Newton showed that these laws of motion, combined with his law of universal gravitation. Newtons laws are applied to objects which are idealised as single point masses, in the sense that the size and this can be done when the object is small compared to the distances involved in its analysis, or the deformation and rotation of the body are of no importance. In this way, even a planet can be idealised as a particle for analysis of its orbital motion around a star, in their original form, Newtons laws of motion are not adequate to characterise the motion of rigid bodies and deformable bodies. Leonhard Euler in 1750 introduced a generalisation of Newtons laws of motion for rigid bodies called Eulers laws of motion, if a body is represented as an assemblage of discrete particles, each governed by Newtons laws of motion, then Eulers laws can be derived from Newtons laws. Eulers laws can, however, be taken as axioms describing the laws of motion for extended bodies, Newtons laws hold only with respect to a certain set of frames of reference called Newtonian or inertial reference frames. Other authors do treat the first law as a corollary of the second, the explicit concept of an inertial frame of reference was not developed until long after Newtons death. In the given mass, acceleration, momentum, and force are assumed to be externally defined quantities. This is the most common, but not the interpretation of the way one can consider the laws to be a definition of these quantities. Newtonian mechanics has been superseded by special relativity, but it is useful as an approximation when the speeds involved are much slower than the speed of light. The first law states that if the net force is zero, the first law can be stated mathematically when the mass is a non-zero constant, as, ∑ F =0 ⇔ d v d t =0. Consequently, An object that is at rest will stay at rest unless a force acts upon it, an object that is in motion will not change its velocity unless a force acts upon it. This is known as uniform motion, an object continues to do whatever it happens to be doing unless a force is exerted upon it. If it is at rest, it continues in a state of rest, if an object is moving, it continues to move without turning or changing its speed
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