AR375 Structural System in Architecture. Skyscraper Building

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1 AR375 Structural System in Architecture Skyscraper Building

2 Building Structural System Roof Moment Resisting Frame Seismic Resisting System Special Designed System Wall and Shear Wall Bearing wall Beam Slab (Floor) Column Footing and Foundation

3 A skyscraper is a tall, continuously habitable building of many stories, usually designed for office and commercial use. There is no official definition or height above which a building may be classified as a skyscraper.

4 A relatively small building may be considered a skyscraper if it protrudes well above its built environment and changes the overall skyline. The maximum height of structures has progressed historically with building methods and technologies and thus what is today considered a skyscraper is taller than before.

5 The Council on Tall Buildings and Urban Habitat (CTBUH) Lately, the term supertall has arisen for the current generation of tall buildings with a structural height of 300 m and more. The CTBUH has now added the term megatall, for buildings with a height of 600 m and more. Although great heights are now being achieved with built tall buildings in excess of 800 m (2,600 ft) at the mid-point of 2011 there [were] only approximately 54 buildings in excess of 300 m (980 ft) completed and occupied globally.

6 Pre-19th century The Great Pyramid of Giza in ancient Egypt built in the 26th century BCE was 146 m (479 ft). The Two Towers of Bologna in the 12th century reached 97.2 m (319 ft) in height.

7 Early skyscrapers In 1852 Elisha Otis introduced the safety elevator, allowing convenient and safe passenger movement to upper floors. Another crucial development was the use of a steel frame instead of stone or brick, otherwise the walls on the lower floors on a tall building would be too thick to be practical. An early development in this area was Oriel Chambers in Liverpool. Designed by local architect Peter Ellis in 1864, the building was the world's first ironframed, glass curtain-walled office building. It was only 5 floors high. Elisha Graves Otis (August 3, 1811 April 8, 1861)

8 Early skyscrapers Further developments led to the world's first skyscraper, the ten-story Home Insurance Building in Chicago, built in While its height is not considered very impressive today, it was at that time. The architect, Major William Le Baron Jenney, created a load-bearing structural frame. In this building, a steel frame supported the entire weight of the walls, instead of loadbearing walls carrying the weight of the building. This development led to the "Chicago skeleton" form of construction.

9 Early skyscrapers The Flatiron Building (or Fuller Building, as it was originally called) is located at 175 Fifth Avenue in the borough of Manhattan, New York City and is considered to be a groundbreaking skyscraper in It was designed by Chicago's Daniel Burnham as a vertical Renaissance palazzo with Beaux-Arts styling. Since it employed a steel skeleton with the steel coming from the American Bridge Company in Pennsylvania it could be built to 22 stories (285 feet) relatively easily, which would have been difficult using other construction methods of that time.

10 Early skyscrapers Early skyscraper caisson foundations, 1898 The Produce Exchange of 1884 made structural advances in metal frame design.

11 Modern skyscrapers In 1930, The Chrysler Building is an Art Deco style skyscraper in New York City, located on the east side of Manhattan in the Turtle Bay area at the intersection of 42nd Street and Lexington Avenue. At 1,046 feet (319 m), the structure was the world's tallest building for 11 months before it was surpassed by the Empire State Building in It is still the tallest brick building in the world, albeit with an internal steel skeleton.

12 Modern skyscrapers In 1931, The Empire State Building is a 102-story skyscraper located in Midtown Manhattan, New York City, at the intersection of Fifth Avenue and West 34th Street. It has a roof height of 1,250 feet (381 meters), and with its antenna spire included, it stands a total of 1,454 ft (443.2 m) high. It stood as the world's tallest building for 40 years, from its completion in 1931 until construction of the World Trade Center's North Tower was completed in 1972.

13 Modern skyscrapers In 1972, The World Trade Center is a site for various buildings in Lower Manhattan, New York City, United States. At the time of their completion, the original 1 World Trade Center (the North Tower) and 2 World Trade Center (the South Tower), known collectively as the Twin Towers, were the tallest buildings in the world. To meet the Port Authority's requirement for 10,000,000 square feet (930,000 m 2 )) of office space, the buildings would each have to be 110 stories tall. It was developed the tube-frame structural system used in the twin towers.

14 Modern skyscrapers In 1972, The Willis Tower (Sears Tower) is a 108-story, 1,451-foot (442 m) skyscraper in Chicago, Illinois.[2] At the time of its completion in 1973, it was the tallest building in the world, surpassing the World Trade Center towers in New York, and it held this rank for nearly 25 years. Their team of architect Bruce Graham and structural engineer Fazlur Khan designed the building as nine square "tubes", each essentially a separate building, clustered in a 3 3 matrix forming a square base with 225-foot (75 m) sides. All nine tubes would rise up to the 50th floor of the building.

15 Modern skyscrapers In 1998, The Petronas Towers are twin skyscrapers in Kuala Lumpur, Malaysia. According to the CTBUH's ranking, they were the tallest buildings in the world from 1998 to 2004 until surpassed by Taipei 101. They feature a diamond-faceted facade consisting of 83,500 square metres (899,000 sq.ft) of stainless steel extrusions. In addition, a 33,000-panel curtain wall cladding system resides within the towers. Highlighting the magnificent towers, they are composed of 55,000 square metres (590,000 sq.ft) of millimetre (0.802 in) laminated glass to reduce heat by reflecting harmful UV rays.

16 Modern skyscrapers The Taipei 101 (the Taipei World Financial Center), is the first building in the world to break the half-kilometer mark in height located in Taipei, Republic of China. The building ranked officially as the world's tallest from 2004 until the opening of the Burj Khalifa in Dubai in In July 2011, the building was awarded LEED Platinum certification. Taipei 101 comprises 101 floors above ground and 5 floors underground. The tower is designed to withstand typhoons and earthquakes. The design achieves both strength and flexibility for the tower through the use of highperformance steel construction. Thirty-six columns support Taipei 101, including eight "mega-columns" packed with 10,000 psi (69 MPa) concrete.[13] Every eight floors, outrigger trusses connect the columns in the building's core to those on the exterior.

17 Modern skyscrapers The Burj Khalifa known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and is the tallest man-made structure in the world, at m (2,722 ft). The tower is designed by Skidmore, Owings and Merrill, which also designed the Willis Tower (formerly the Sears Tower) in Chicago and the new One World Trade Center in New York City. The Burj Khalifa uses the bundled tube design. The engineers developed a new structural system called the buttressed core, which consists of a hexagonal core reinforced by three buttresses that form the Y' shape. This structural system enables the building to support itself laterally and keeps it from twisting. The primary structure is reinforced concrete. Over 45,000 m 3 of concrete were used to construct the concrete and steel foundation, which features 192 piles. It used 330,000 m 3 of concrete and 55,000 tons of steel rebar, and construction took 22 million man-hours. The remaining structure above is constructed of lighter steel.

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19 Future skyscrapers The Burj Mubarak al Kabir is a proposed 250 km2 (62,000-acre) planned urban area in Subiya, Kuwait, an area just opposite Kuwait City. The main attraction of Madinat al-hareer, the Burj Mubarak al- Kabir will stand at 1,001 m (3,284 ft) tall. The development will cost an estimated 94 billion USD. The Kingdom Tower (Burj al Mamlakah), previously is a supertall skyscraper proposed for construction in Jeddah, Saudi Arabia. The tower was initially planned to be 1.6- kilometre (1 mi) high. The building has been scaled down from its initial 1.6 km (about one mile) proposal, which was never fully designed, to a height of at least 1,000 metres (3, ft).

20 Future skyscrapers Name Pinnacle height Year of first proposal Structure type Country Town The Space Elevator 100,000 km (62,000 mi) 1959 Massivespace tether Several undetermined The Launch loop 80 km (50 mi) 1981 SuspendedMaglev Track U.S. undetermined Scaled-downSpace Elevator 20 km (12 mi) 2009 Massivespace tether Canada undetermined X-Seed ,000 m (13,000 ft) 1995 Arcology Japan Tokyo Ultima Tower 3,217 m (10,554 ft) 1991 Skyscraper U.S. undetermined Dubai City Tower 2,400 m (7,900 ft) 2008 Skyscraper United Arab Emirates Dubai Shimizu Mega-City Pyramid 2,004 m (6,575 ft) 1996 Arcology Japan Tokyo Millennium Challenge Kuwait (Possible 1,852 m (6,076 ft) 2005 Skyscraper Tower location) undetermined Citygate Ecotower 1,500 m (4,900 ft) 2007 Skyscraper UK London Bionic Tower 1,228 m (4,029 ft) 1997 Arcology China Hong Kong Hong Kong Azerbaijan Tower 1,050 m (3,440 ft) 2012 Skyscraper Azerbaijan Baku

21 Basic design considerations Good structural design is important in most building design, but particularly for skyscrapers since even a small chance of catastrophic failure is unacceptable given the high price. This presents a paradox to civil engineers: the only way to assure a lack of failure is to test for all modes of failure, in both the laboratory and the real world. But the only way to know of all modes of failure is to learn from previous failures. Thus, no engineer can be absolutely sure that a given structure will resist all loadings that could cause failure, but can only have large enough margins of safety such that a failure is acceptably unlikely. When buildings do fail, engineers question whether the failure was due to some lack of foresight or due to some unknowable factor.

22 Loading and vibration The load a skyscraper experiences is largely from the force of the building material itself. In most building designs, the weight of the structure is much larger than the weight of the material that it will support beyond its own weight. In technical terms, the dead load, the load of the structure, is larger than the live load, the weight of things in the structure (people, furniture, vehicles, etc.). As such, the amount of structural material required within the lower levels of a skyscraper will be much larger than the material required within higher levels. This is not always visually apparent. The Empire State Building's setbacks are actually a result of the building code at the time, and were not structurally required. On the other hand John Hancock Center's shape is uniquely the result of how it supports loads. Vertical supports can come in several types, among which the most common for skyscrapers can be categorized as steel frames, concrete cores, tube within tube design, and shear walls. The wind loading on a skyscraper is also considerable. In fact, the lateral wind load imposed on super-tall structures is generally the governing factor in the structural design. Wind pressure increases with height, so for very tall buildings, the loads associated with wind are larger than dead or live loads. Other vertical and horizontal loading factors come from varied, unpredictable sources, such as earthquakes.

23 Shear walls A shear wall, in its simplest definition, is a wall where the entire material of the wall is employed in the resistance of both horizontal and vertical loads. A typical example is a brick or cinderblock wall. Since the wall material is used to hold the weight, as the wall expands in size, it must hold considerably more weight. Due to the features of a shear wall, it is acceptable for small constructions, such as suburban housing or an urban brownstone, to require low material costs and little maintenance. In this way, shear walls, typically in the form of plywood and framing, brick, or cinderblock, are used for these structures. For skyscrapers, though, as the size of the structure increases, so does the size of the supporting wall. Large structures such as castles and cathedrals inherently addressed these issues due to a large wall being advantageous (castles), or ingeniously designed around (cathedrals). Since skyscrapers seek to maximize the floor-space by consolidating structural support, shear walls tend to be used only in conjunction with other support systems.

24 Steel frame The classic concept of a skyscraper is a large steel box with many small boxes inside it. The genius of the steel frame is its simplicity. By eliminating the inefficient part of a shear wall, the central portion, and consolidating support members in a much stronger material, steel, a skyscraper could be built with both horizontal and vertical supports throughout. This method, though simple, has drawbacks. Chief among these is that as more material must be supported (as height increases), the distance between supporting members must decrease, which actually in turn, increases the amount of material that must be supported. This becomes inefficient and uneconomic for buildings above 40 stories tall as usable floor spaces are reduced for supporting column and due to more usage of steel.

25 Tube structural systems Since 1963, a new structural system of framed tubes appeared. Fazlur Khan and J. Rankine defined the framed tube structure as "a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation."[43] Closely spaced interconnected exterior columns form the tube. Horizontal loads (primarily wind) are supported by the structure as a whole. About half the exterior surface is available for windows. Framed tubes allow fewer interior columns, and so create more usable floor space. Where larger openings like garage doors are required, the tube frame must be interrupted, with transfer girders used to maintain structural integrity. Tube structures cut down costs, at the same time allow buildings to reach greater heights. Tube-frame construction was first used in the DeWitt-Chestnut Apartment Building, completed in Chicago in It was used soon after for the John Hancock Center and in the construction of the World Trade Center.

26 Tube structural systems The tubular systems are fundamental to tall building design. Most buildings over 40-storeys constructed since the 1960s now use a tube design derived from Khan s structural engineering principles,[3][42] examples including the construction of the World Trade Center, Aon Centre[disambiguation needed], Petronas Towers, Jin Mao Building, and most other supertall skyscrapers since the 1960s.[35] The strong influence of tube structure design is also evident in the construction of the current tallest skyscraper, the Burj Khalifa. Framed tube Trussed tube and X-bracing Bundle tube Concrete tube structures

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28 AR375 Structural System in Architecture Dr. Punravee Kongboontiam Faculty of Architecture and Environmental Design Maejo University