Floating Raft System
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Floating Raft System
Floating raft is a land-based building foundation that protects it against settlement and liquefaction of soft soil from seismic activity. It was a necessary innovation in the development of tall buildings in the wet soil of Chicago in the 19th century, when it was developed by John Wellborn Root who came up with the idea of interlacing the concrete slab with steel beams. The earliest precursor to the modern version may be the concrete rafts developed for the building of Millbank Prison in 1815 by Robert Smirke. For a floating raft foundation – or simply "floating foundation" – the foundation has a volume such that, if that volume filled with soil, it would be equal in weight to the total weight of the structure. When the soil is so soft that not even friction piles will support the building load, these types of foundation are the final option and makes the building behave like a boat: obeying Archimedes' principle, buoyed up by the weight of the earth displaced in creating ...
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Foundation (architecture)
In engineering, a foundation is the element of a structure which connects it to the ground, transferring loads from the structure to the ground. Foundations are generally considered either shallow or deep. Foundation engineering is the application of soil mechanics and rock mechanics ( geotechnical engineering) in the design of foundation elements of structures. Purpose Foundations provide the structure's stability from the ground: * To distribute the weight of the structure over a large area in order to avoid overloading the underlying soil (possibly causing unequal settlement). * To anchor the structure against natural forces including earthquakes, floods, droughts, frost heaves, tornadoes and wind. * To provide a level surface for construction. * To anchor the structure deeply into the ground, increasing its stability and preventing overloading. * To prevent lateral movements of the supported structure (in some cases). Requirements of a good foundation The design and the ...
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Soil Liquefaction
Soil liquefaction occurs when a cohesionless saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress such as shaking during an earthquake or other sudden change in stress condition, in which material that is ordinarily a solid behaves like a liquid. In soil mechanics, the term "liquefied" was first used by Allen Hazen in reference to the 1918 failure of the Calaveras Dam in California. He described the mechanism of flow liquefaction of the embankment dam as: The phenomenon is most often observed in saturated, loose (low density or uncompacted), sandy soils. This is because a loose sand has a tendency to compress when a load is applied. Dense sands, by contrast, tend to expand in volume or 'dilate'. If the soil is saturated by water, a condition that often exists when the soil is below the water table or sea level, then water fills the gaps between soil grains ('pore spaces'). In response to soil compressing, the po ...
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Skyscrapers
A skyscraper is a tall continuously habitable building having multiple floors. Modern sources currently define skyscrapers as being at least or in height, though there is no universally accepted definition. Skyscrapers are very tall high-rise buildings. Historically, the term first referred to buildings with between 10 and 20 stories when these types of buildings began to be constructed in the 1880s. Skyscrapers may host offices, hotels, residential spaces, and retail spaces. One common feature of skyscrapers is having a steel frame that supports curtain walls. These curtain walls either bear on the framework below or are suspended from the framework above, rather than resting on load-bearing walls of conventional construction. Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than of those made of reinforced concrete. Modern skyscrapers' walls are not load-bearing, and most skyscrapers are characterised by large surface ...
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Chicago
(''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_type2 = Counties , subdivision_name1 = Illinois , subdivision_name2 = Cook and DuPage , established_title = Settled , established_date = , established_title2 = Incorporated (city) , established_date2 = , founder = Jean Baptiste Point du Sable , government_type = Mayor–council , governing_body = Chicago City Council , leader_title = Mayor , leader_name = Lori Lightfoot ( D) , leader_title1 = City Clerk , leader_name1 = Anna Valencia ( D) , unit_pref = Imperial , area_footnotes = , area_tot ...
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John Wellborn Root
John Wellborn Root (January 10, 1850 – January 15, 1891) was an American architect who was based in Chicago with Daniel Burnham. He was one of the founders of the Chicago School style. Two of his buildings have been designated a National Historic Landmark; others have been designated Chicago landmarks and listed on the National Register of Historic Places. In 1958, he was posthumously awarded the AIA Gold Medal. Early years and education John Wellborn Root was born in 1850 in Lumpkin, Georgia, the son of Sidney Root, a planter, and his wife, Mary Harvey Clark. He was named after a maternal uncle, Marshall Johnson Wellborn. Root was raised in Atlanta, where he was first educated at home. When Atlanta fell to the Union during the American Civil War, Root's father sent young Root and two other boys on a steamer to the United Kingdom, where his father, Sidney, had a shipping business based in Liverpool, England. His mother and sister went to Cuthbert, Georgia. While in ...
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Millbank Prison
Millbank Prison or Millbank Penitentiary was a prison in Millbank, Westminster, London, originally constructed as the National Penitentiary, and which for part of its history served as a holding facility for convicted prisoners before they were transported to Australia. It was opened in 1816 and closed in 1890. Construction The site at Millbank was originally purchased in 1799 from the Marquess of Salisbury for £12,000 by the philosopher Jeremy Bentham, acting on behalf of the Crown, for the erection of his proposed panopticon prison as Britain's new National Penitentiary. After various changes in circumstance, the Panopticon plan was abandoned in 1812. Proposals for the National Penitentiary continued, however, and were given a legislative basis in the Penitentiary House, etc. Act of 1812 (52 Geo. 3 c. 44). An architectural competition for a new prison building on the Millbank site attracted 43 entrants: the winning design was that of William Williams, drawing master at the ...
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Robert Smirke (architect)
Sir Robert Smirke (1 October 1780 – 18 April 1867) was an English architect, one of the leaders of Greek Revival architecture, though he also used other architectural styles. As architect to the Board of Works, he designed several major public buildings, including the main block and façade of the British Museum. He was a pioneer of the use of concrete foundations. Background and training Smirke was born in London on 1 October 1780, the second son of the portrait painter Robert Smirke; he was one of twelve children.page 73, J. Mordaunt Crook: ''The British Museum A Case-study in Architectural Politics'', 1972, Pelican Books He attended Aspley School, Aspley Guise, Bedfordshire,page 74, J. Mordaunt Crook: ''The British Museum A Case-study in Architectural Politics'', 1972, Pelican Books where he studied Latin, Greek, French and drawing, and was made head boy at the age of 15. In May 1796 he began his study of architecture as a pupil of John Soane but left after only a ...
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Friction Pile
A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site. There are many reasons that a geotechnical engineer would recommend a deep foundation over a shallow foundation, such as for a skyscraper. Some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints like property lines. There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally driven into the ground in situ; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering discipli ...
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Building Load
A building, or edifice, is an enclosed structure with a roof and walls standing more or less permanently in one place, such as a house or factory (although there's also portable buildings). Buildings come in a variety of sizes, shapes, and functions, and have been adapted throughout history for a wide number of factors, from building materials available, to weather conditions, land prices, ground conditions, specific uses, prestige, and aesthetic reasons. To better understand the term ''building'' compare the list of nonbuilding structures. Buildings serve several societal needs – primarily as shelter from weather, security, living space, privacy, to store belongings, and to comfortably live and work. A building as a shelter represents a physical division of the human habitat (a place of comfort and safety) and the ''outside'' (a place that at times may be harsh and harmful). Ever since the first cave paintings, buildings have also become objects or canvasses of much artistic ...
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Archimedes' Principle
Archimedes' principle (also spelled Archimedes's principle) states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially, is equal to the weight of the fluid that the body displaces. Archimedes' principle is a law of physics fundamental to fluid mechanics. It was formulated by Archimedes of Syracuse. Explanation In ''On Floating Bodies'', Archimedes suggested that (c. 246 BC): Archimedes' principle allows the buoyancy of any floating object partially or fully immersed in a fluid to be calculated. The downward force on the object is simply its weight. The upward, or buoyant, force on the object is that stated by Archimedes' principle above. Thus, the net force on the object is the difference between the magnitudes of the buoyant force and its weight. If this net force is positive, the object rises; if negative, the object sinks; and if zero, the object is neutrally buoyant—that is, it remains in place without either rising ...
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Buoyancy
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the displaced fluid. For this reason, an object whose average density is greater than that of the fluid in which it is submerged tends to sink. If the object is less dense than the liquid, the force can keep the object afloat. This can occur only in a no ...
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Building Construction
Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and comes from Latin ''constructio'' (from ''com-'' "together" and ''struere'' "to pile up") and Old French ''construction''. To construct is the verb: the act of building, and the noun is construction: how something is built, the nature of its structure. In its most widely used context, construction covers the processes involved in delivering buildings, infrastructure, industrial facilities and associated activities through to the end of their life. It typically starts with planning, financing, and design, and continues until the asset is built and ready for use; construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual demolition, dismantling or decommissioning. The constructio ...
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