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Evolution of Skyscrapers Essay1.Historical Development In High-Rise structuresAncient Skyscrapers The Great zikkurat of BabylonPerhaps the nearly impressive social organisation in the ancient Middle East, the Great Ziggurat of Babylon was make over a span of several decades in the Sixth Century BC. Its seven stories, built upon a squ atomic number 18 foundation, stretched 300 feet into the sky. Some think it was the inspiration for the infamous predominate of Babel in the Book of Genesis. In this illustration, King Nebuchadnezzar, who ruled Babylon from 604 to 561 BC, is seen overlooking his capitalThe towers of bolognaThe towers of and were built in Europe, or to tuckerher until Bologna argon slender, as much as 60 meters (150 feet) lanky, by the rich for defense and as spot symbols. No other site perhaps the ara, had so many a nonher(prenominal) stately structures crowded the coming of skyscrapers in the late 19th century.Fig. 1 The great Ziggurat of BabylonAs ma ny as 180 towers, of many different heights, atomic number 18 thought to establish been built in Bologna during the 1100s and slightly later straightaway there ar b atomic number 18ly 20. The two most prominent (seen here) argon the symbols of the city and have gigantic been known together as the Two Towers.Fig. 2 The towers of BolognaThe First Safety ElevatorsIn this plosive illustration, shoppers ride the elevator in the new Lord Taylors department store on Broadway in naked York City sometime during the 1870s. Around the same time, the commencement-ever elevator in an office mental synthesis was excessively ins nobleed in naked as a jaybird York. It was intentional by Elisha Otis, whose company became synonymous with the new contraption. Elevators rotary motionized office buildings, literally turning them superlative down. Prior to their invention, the lower downs of a structure were the most valuable rental property because of the difficulty and nettle of clim bing the stairs. But the elevator made it possible for elite tenants to enjoy the view from the upper floors and get buildings to rise higher and higher.Fig. 3 The first Safety ElevatorsGreat bread FireIn this illustration, Chicago residents flee the terror of the Chicago energize which devastated their city over a three-day period in October 1871. The fire ca utilize nearly $200 million in damage, killed some 300 volume and left another 100,000 home slight. in spite of this toll, the destruction cleared the way for Chicago to build scores of modern steel-framed office towers and to become integrity of Americas most architecturally striking cities.Fig. 4 Great Chicago FireThe First skyscraperChicagos 10-story Home insurance policy Building, built in 1884 and foundinged by William Jenney, was arguably the first true modern office tower. It was the first building to use structural steel at least partially in its frame, and was the first pompous building to be fireproofed tw o inside and outside. It was torn down in 1931 but its legacy lives on in thousands of steel-framed and fireproofed buildings around the world.Fig. 5 Home Insurance BuildingThe Tribune TowerPedestrians walk past the flowery entrance and lower floors of Tribune Tower, home of the Chicago Tribune newspaper, which was built in 1925. The 36-story Gothic Revival structure was designed by John Mead Howells and Raymond Hood, who won a contest held by the newspaper company to create the most beautiful and distinctive office building in the world.Fig. 6 The Tribune TowerThe Chrysler BuildingWith its majestic spire, New York Citys Chrysler Building is perhaps the most famous Art Deco structure in the world. Built in 1930, the 77-storey structure was briefly the tallest building in the world. The sculptures at the top and around the edges are actually godlike by Chrysler hubcaps and hood ornaments. The buildings tapering profile is perhaps the best example of form follows zoning by winning N ew York Citys setback requirements from 1916 zoning laws requiring new structures to leave more open space around them and turning them into an stunning archetypeFig. 7 The Chrysler BuildingThe empire State Building survives a hitThis mental picture shows the spot where a B-25 bomber struck the Empire State Building in July 1945. The aircraft was ferrying servicemen from mum to New Yorks La Guardia Airport when pilot William Smith veered disastrously off course in menacing fog. Fourteen people including Smith were killed when the bomber hit the skyscraper. The buildings 79th floor caught fire, and New York City firefighters bravely speed up into the building to rescue occupants and put out the blaze. The buildings structure and fireproofing both proved strong enough that the New York landmark re open up the following week.Fig. 8 The Empire State Building valet Trade centreThe famous twin towers of the World Trade core group were built by the Port Authority in the 1960s as part of an effort to revitalize lower Manhattan. The structure was derided by critics as boring. superstar wag likened it to a hulk pair of filing cabinets, but in time it became a normal New York landmark. The original WTC was the first to use sky lobbies where people would change from express to local anaesthetic elevators, a setup inspired by the New York subway system. It also had wide-open, column-free spaces that were ideal for Fig. 9 The World Trade Centre the cubicles then becoming popular in office design. The towers were destroyed in the 2001 terrorist bombardment that killed more than 2,700 peopleSears TowerWhen the Sears Tower, later renamed the Willis Tower, opened in 1973, the 108-story structure became the tallest building in the world and held that title until Malaysias Petronas Towers claimed the distinction in 1998. This skyscraper was able to achieve that height through a spectacular engineering science innovation that introduced the bundled tube structure the Sears Tower is really nine square towers bundled together. It was the start of a revolution in structural design that permitted higher and thinner towers than had ever been built beforeFig. 10 The Sears TowerThe Citicorp Building Skirts DisasterThe 59-story Citigroup Center building, absolute in 1977, had to undergo a costly strength stir the following year after it was discovered that the structure was dangerously vulnerable to strong diagonal uprises impinging the buildings corners. This weakness was a consequence of the placement of the main support columns at the centre of the sides rather than on the corners because the building had to float over a church that owned the property. This bold design did win flattery for the architect but he subsequently had to suffer the consequences largely in secret lest panic block out of experimenting with untested structural elements. If strong dangerous winds had actually toppled the Citicorp building, it is estimated that it mi ght have taken 16 blocks of Manhattan with it.Fig. 11 The Citicorp BuildingThe Petronas TowerTourists have their picture taken outside the soaring spires of the Petronas Towers in Kuala Lumpur, Malaysia. The 88-story towers, which were completed in the mid-to-late 1990s, were for several years the worlds tallest buildings. The project was the harbinger of a global shift in skyscraper building in which Middle Eastern and Asian countries have been racing to erect the tallest and most majestic towers Fig. 12 The Petronas TowerThe Gherkin, LondonOne of the more unusual sights in the London skyline is 20 St. bloody shame Axe, a 41-story office tower opened in 2004, which is nicknamed The Gherkin because of its resemblance to a pickle. Though odd-looking, the structure is a prototype for a new generation of innovative, super energy-efficient buildings. Vertical gaps in the building create a natural ventilation system that allows warm air to rise out of the structure. These openings also a llow the intragroup offices to use more Fig. 13 The 20 St. Mary Axe natural light to greatly reduction electrical consumptionThe Marina Bay SandsSingapores Marina Bay Sands, a casino and resort complex which opened in 2011, cost an astonishing $8 billion to build. Architect Moshie Safdies unorthodox design, with its trio of 55-story towers, reportedly was inspired by card decks on gaming tables. The three towers are connected by a giant terrace that supports the worlds longest elevated swimming pool. The steel for the pool weighs 191,416 kilos (422,000 pounds) and the water it can hold weighs an additional 1,424,098 kilos (3,139,600 pounds). The towers are constructed to allow movement in the wind up to 50 centimetres and longer-term settling in the soil.Fig. 14 The Marina Bay SandsBurj KhalifaDubais 160-storey Burj Khalifa, which opened in 2010, is by far the worlds tallest building. Its startling, rocket ship-like appearance, seen in this photo, seems intended to get attentio n more than anything else. As architectural critic Paul Goldberger has written, You dont build this kind of skyscraper to house people you do it to make sure the world knows who you are. The tall, tapering design is reminiscent of skyscrapers like the Chrysler Fig. 15 The Burj Khalifa and Empire State buildings although you could put the two New York skyscrapers one on top of the other and they still would not be as tall.The New World Trade CentreOne World Trade Center (also known as Tower One) rises over lower Manhattan on the site of where the twin towers destroyed in 2001. When completed in 2013, it will have a spire thats precisely 1,776 feet tall (541 meters), making it the leash tallest building in the world and the highest in the Western Hemisphere. The new WTCs base is enclosed in compact concrete, steel panels and blast-resistant glass, making it one of the toughest skyscrapers ever built, but security concerns have caused the buildings cost to soar, r all(prenominal)ing the neighbourhood of $4 billion.Fig. 16The New World Trade CentreFig. 17 Height Comparison of Noticeable tall Buildings2. Classification of Tall Building Structure SystemIn 1969 Fazlur Khan classified structural systems for tall buildings relating to their heights with considerations for efficiency in the form of Heights for Structural Systems diagramsFig. 18 Classification of Tall Building Structure System by Fazlur Khan. Left steel Right ConcreteHe developed these schemes for both steel and concrete. Khan argued that the rigid frame that had dominated tall building design and construction so long was not the only system fitting for tall buildings. Because of a better understanding of the mechanics of material and member behavior, he reasoned that the structure could be hardened in a holistic manner, that is, the building could be analyzed in three dimensions, supported by ready reckoner simulations, rather than as a series of planar systems in each principal direction. Feasib le structural systems, according to him, are rigid frames, dress walls, interactive frame- hook wall combinations, belt trusses, and the various other tubular systems. Structural systems of tall buildings can be divided into two broad categories home(a) structures and exterior structures.This classification is based on the distribution of the components of the primary lateral load-resisting system over the building. A system is categorized as an privileged structure when the major part of the lateral load resisting system is located within the interior of the building. Likewise, if the major part of the lateral load-resisting system is located at the building perimeter, a system is categorized as an exterior structure. It should be noted, however, that any interior structure is likely to have some small components of the lateral load-resisting system at the building perimeter, and any exterior structure may have some minor components within the interior of the building. This classification of structural systems is presented more as a guideline and should be treated as such. It is imperative that each system has a wide range of height applications depending upon other design and service criteria related to building shape, feel ratio, architectural functions, load conditions, building stability and site constraints.For each condition, however, there is always an optimum structural system, although it may not necessarily match one of those in the systems tables due to the predominant influence of other factors on the building form. The height limits shown are therefore presumptive based on experience and the authors prediction within an acceptable range of aspect ratios of the buildings, say about 6 to 8. On occasions, an exterior structure may be combined with an interior one, such as when a tubular frame is also braced or provided with core-supported outriggers and belt trusses, to rise the buildings stiffness 2.1 Interior Structures The two basic type s of lateral load-resisting systems in the category of interior structures are the moment-resisting frames and shear trusses/shear walls.These systems are usually arranged as planar assemblies in two principal orthogonal directions and may be employed together as a combined system in which they interact. Another very important system in this category is the core-supported outrigger structure, which is very widely used for super tall buildings at this writing. The moment-resisting frame (MRF) consists of horizontal (girder) and just (column) members rigidly connected together in a planar grid form. Such frames resist load primarily through the flexural stiffness of the members (Kowalczyk, Sinn, Kilmister, 1995).The size of the columns is mainly controlled by the gravity fill up that accumulate towards the base of the building giving rise to more and more larger column sizes towards the base from the roof. The size of the girders, on the other hand, is controlled by stiffness of the frame in order to ensure acceptable lateral sway of the building. Although gravity load is more or less the same in all typical floors of a tall building, the girder sizes need to be add-ond to outgrowth the frame stiffness. Likewise, columns already sized for gravity loads need to be slightly increased to increase the frame stiffness as well. MRFs can be located in or around the core, on the exterior, and throughout the interior of the building along grid lines.Table 1 Interior Structures braced frames are laterally supported by vertical steel trusses, also called shear trusses, which resist lateral loads primarily through axial stiffness of the members. These act as vertical cantilever trusses where the columns act as chord members and the concentric K, V, or X braces act as web members. Such systems are called concentric braced frames (CBF).Eccentric braced frames (EBF) have, on the other hand, braces which are connected to the floor girders that form horizontal elements of the truss, with axial offsets to introduce flexure and shear into the frame (Popov, 1982). This lowers stiffness-to-weight ratio but increases ductileness and therefore EBFs are used for seismic zones where ductility is an essential requirement of structural design. EBFs can also be used to accommodate wide doors and other openings, and have on occasions been used for non-seismic zones (Corrin Swensson, 1992). Braced frames are generally located in the service and elevator core areas of tall buildings.The frame diagonals are enclosed within the walls. Reinforced concrete planar solid or coupled shear walls have been one of the most popular systems used for high-rise construction to resist lateral forces caused by wind and earthquakes. They are treated as vertical cantilevers fixed at the base. When two or more shear walls in the same plane are interconnected by beams or slabs, as is the case with shear walls with door or window openings, the total stiffness of the system exceeds t he sum of the individual wall stiffnesses. This is so because the connecting beam forces the walls to act as a single unit by restraining their individual cantilever actions.These are known as coupled shear walls. Shear walls used in tall office buildings are generally located around service and elevator cores, and stairwells. In fact, in many tall buildings, the vertical solid core walls that enclose the building services can be used to stabilize and fasten the building against lateral loads. Many possibilities exist with single or multiple cores in a tall building with regard to their location, shape, number, and arrangement. The core walls are essentially shear walls that can be analyzed as planar elements in each principal direction or as three-dimensional elements using computer programs.