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Precast Concrete
Precast concrete is a construction product produced by casting concrete in a reusable molding (process), mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples include precast beam (structure), beams, and wall panels, floors, roofs, and piles. In contrast, cast-in-place concrete is poured into site-specific forms and cured on site. Recently lightweight expanded polystyrene foam is being used as the cores of precast wall panels, saving weight and increasing thermal insulation. Precast stone is distinguished from precast concrete by the finer construction aggregate, aggregate used in the mixture, so the result approaches the natural product. Overview Precast concrete is employed in both interior and exterior applications, from highway, bridge, and high-rise projects to parking structures, K-12 schools, warehouses, mixed-use, and industrial building construction. By producing precast concrete in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Culvert
A culvert is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe (fluid conveyance), pipe, reinforced concrete or other material. In the United Kingdom, the word can also be used for a longer artificially buried watercourse. Culverts are commonly used both as cross-drains to relieve drainage of ditches at the roadside, and to pass water under a road at natural drainage and stream crossings. When they are found beneath roads, they are frequently empty. A culvert may also be a bridge-like structure designed to allow vehicle or pedestrian traffic to cross over the waterway while allowing adequate passage for the water. Dry culverts are used to channel a fire hose beneath a noise barrier for the ease of firefighter, firefighting along a highway without the need or danger of placing hydrants along the roadway itself. Culverts come in many sizes and shapes including ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polystyrene
Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to air and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used plastics, with the scale of its production being several million tonnes per year. Polystyrene is naturally transparent to visible light, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and optical disc jewel cases), containers, lids, bottles, trays, tumblers, disposable cutlery, in the making of models, and as an alternative material for phonograph records. As a thermoplastic polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled. This te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precast Parking Structure
Precast concrete is a construction product produced by casting concrete in a reusable mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples include precast beams, and wall panels, floors, roofs, and piles. In contrast, cast-in-place concrete is poured into site-specific forms and cured on site. Recently lightweight expanded polystyrene foam is being used as the cores of precast wall panels, saving weight and increasing thermal insulation. Precast stone is distinguished from precast concrete by the finer aggregate used in the mixture, so the result approaches the natural product. Overview Precast concrete is employed in both interior and exterior applications, from highway, bridge, and high-rise projects to parking structures, K-12 schools, warehouses, mixed-use, and industrial building construction. By producing precast concrete in a controlled environment (typically referred to as a precast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
I-beam
An I-beam is any of various structural members with an - (serif capital letter 'I') or H-shaped cross section (geometry), cross-section. Technical terms for similar items include H-beam, I-profile, universal column (UC), w-beam (for "wide flange"), universal beam (UB), rolled steel joist (RSJ), or double-T (especially in Polish language, Polish, Bulgarian language, Bulgarian, Spanish language, Spanish, Italian language, Italian, and German language, German). I-beams are typically made of structural steel and serve a wide variety of construction uses. The horizontal elements of the are called flanges, and the vertical element is known as the "web". The web resists shear forces, while the flanges resist most of the bending moment experienced by the beam. The Euler–Bernoulli beam equation shows that the -shaped section is a very efficient form for carrying both bending and shearing (physics), shear loads in the plane of the web. On the other hand, the cross-section has a reduced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prestressed Concrete
Prestressed concrete is a form of concrete used in construction. It is substantially prestressed (Compression (physics), compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. Post-tensioned concreted is "structural concrete in which internal stresses have been introduced to reduce potential tensile stresses in the concrete resulting from loads." It was patented by Eugène Freyssinet in 1928. This compression is produced by the Tension (physics), tensioning of high-strength ''tendons'' located within or adjacent to the concrete and is done to improve the performance of the concrete in service. Tendons may consist of single wires, multi-wire Wire rope, strands or threaded bars that are most commonly made from high-tensile steels, carbon fiber or aramid fiber. The essence of prestressed concrete is that once the initial compression has been applied, the resulting material has the characteristics of high-strength concre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cattle Grid
A cattle grid – also known as a stock grid in Australia; cattle guard, or cattle grate in American English; vehicle pass, or stock gap in the Southeastern United States; Texas gate in western Canada and the northwestern United States; and a cattle stop in New Zealand English – is a type of obstacle used to prevent livestock, such as sheep, cattle, Domestic pig, pigs, horses, or mules from passing along a road or railway which penetrates the fencing surrounding an enclosed piece of land or border. It consists of a depression in the road covered by a transverse grid of bars or tubes, normally made of metal and firmly fixed to the ground on either side of the depression, so that the gaps between them are wide enough for an animal's feet to enter, but sufficiently narrow not to impede a wheeled vehicle or human foot. This provides an effective barrier to animals without impeding wheeled vehicles, as the animals are reluctant to walk on the grates. Origins The modern cattle grid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebar
Rebar (short for reinforcement bar or reinforcing bar), known when massed as reinforcing steel or steel reinforcement, is a tension device added to concrete to form ''reinforced concrete'' and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under compression, but has low tensile strength. Rebar usually consists of steel bars which significantly increase the tensile strength of the structure. Rebar surfaces feature a continuous series of ribs, lugs or indentations to promote a better bond with the concrete and reduce the risk of slippage. The most common type of rebar is carbon steel, typically consisting of hot-rolled round bars with deformation patterns embossed into its surface. Steel and concrete have similar coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal differential stress as the temperature changes. Other readily available types of rebar are manufacture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Railway History
''Australian Railway History'' is a monthly magazine covering railway history in Australia, published by the New South Wales Division of the Australian Railway Historical Society on behalf of its state and territory Divisions. History and profile It was first published in 1937 as the ''Australasian Railway and Locomotive Historical Society Bulletin''. It was renamed ''ARHS Bulletin'' in 1952. In January 2004, the magazine was re-branded as ''Australian Railway History''. Historically, the magazine had a mix of articles dealing with historical material and items on current events drawn from its affiliate publications. Today, it contains only historical articles, two or three of them being in-depth. References Publication details *''Australian Railway History: bulletin of the Australian Railway Historical Society'' Redfern, New South Wales Vol. 55, no. 795 (Jan. 2004)- *''Bulletin (Australian Railway Historical Society The Australian Railway Historical Society (AR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New South Wales Government Railways
New South Wales Government Railways (NSWGR) was an agency of the Government of New South Wales that administered rail transport in the colony, and then the state, of New South Wales, Australia, between 1855 and 1932. History The NSWGR built its entire route network to standard gauge A standard-gauge railway is a railway with a track gauge of . The standard gauge is also called Stephenson gauge (after George Stephenson), international gauge, UIC gauge, uniform gauge, normal gauge in Europe, and SGR in East Africa. It is the .... Its first line, also the first railway of New South Wales, was the railway line from Sydney to Parramatta (today: Granville railway station) completed in 1855. The agency was managed by a range of different commission structures between 1857 and 1932, which reported to either the Minister for Public Works or the Minister for Transport. The inaugural Chief Commissioner was Ben Martindale and, following the enactment of the he became Commissi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller islands. It has a total area of , making it the list of countries and dependencies by area, sixth-largest country in the world and the largest in Oceania. Australia is the world's flattest and driest inhabited continent. It is a megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and Climate of Australia, climates including deserts of Australia, deserts in the Outback, interior and forests of Australia, tropical rainforests along the Eastern states of Australia, coast. The ancestors of Aboriginal Australians began arriving from south-east Asia 50,000 to 65,000 years ago, during the Last Glacial Period, last glacial period. By the time of British settlement, Aboriginal Australians spoke 250 distinct l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Million Programme
The Million Programme () was a large public housing program implemented in Sweden between 1965 and 1974 by the governing Swedish Social Democratic Party to ensure the availability of affordable, high-quality housing to all Swedish citizens. The program sought to construct one million new housing dwellings over a ten-year period, which it accomplished. As part of its intention to modernize Swedish housing, it also demolished many older buildings that national and local governments considered obsolescent, unhealthy or derelict. At the time, the intention to build one million new homes in a nation with a population of eight million made the Million Programme the most ambitious building programme in the world. In contrast to the social housing proposals of many other developed countries, which is Means test, targeted at those with low incomes, the Million Programme was a universal program intended to provide housing to Swedish people at a variety of income levels. Background The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
