Architecture

ARCH An arch is a structure that spans a space and supports structure and weight above it. Arches appeared as early as the 2nd millennium BC inMesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures. An arch is a pure compression form. It can span a large area by resolving forces into compressive stresses and, in turn eliminating tensile stresses. This is sometimes referred to as arch action. As the forces in the arch are carried to the ground, the arch will push outward at the base, called thrust. As the rise, or height of the arch decreases, the outward thrust increases. In order to maintain arch action and prevent the arch from collapsing, the thrust needs to be restrained, either with internal ties, or external bracing, such as abutments. EX. Arch of Constantine,Rome, Italy commemorating a victory by Constantine I in 312 AD The Arc de Triomphe,Paris; a 19th-century triumphal arch modeled on the classical Romandesign Catenary arches insideCasa Milà in Barcelona,Spain by Antoni Gaudí CANTILEVER A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is forced against by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trussesor slabs. This is in contrast to a simply supported beam such as those found in a post and lintel system. A simply supported beam is supported at both ends with loads applied between the supports. Cantilevers are widely found in construction, notably in cantilever bridges and balconies (see corbel). In cantilever bridges the cantilevers are usually built as pairs, with each cantilever used to support one end of a central section. The Forth Bridge in Scotland is an example of a cantilever truss bridge. A cantilever in a traditionally timber framed building is called a jetty or forebay. In the southern United States a historic barn type is the cantilever barn of log construction. EX. The Forth Bridge, a cantilever truss bridge. A cantilever balcony of theFallingwater house, byFrank Lloyd Wright. Howrah Bridge in India, a cantilever bridge.

POST AND LINTEL Post and lintel, "prop and lintel" or "trabeated" is a simple construction method using a lintel, header, or architrave as the horizontal member over a building void supported at its ends by two vertical columns, pillars, or posts. This architectural system and building method has been commonly used for centuries to support the weight of the structure located above the openings created by windows and doors in a bearing wall. Post and lintel is different than a beam joined between two posts, it must pass over the tops of the supports. Post-and-beam is a general term for any kind of timber framing.

In architecture, a post-and-lintel or trabeated system refers to the use of horizontal beams or lintels which are borne up by columns or posts. The name is from the Latin trabs, beam; influenced by trabeatus, clothed in the trabea, a ritual garment. The trabeated system is a fundamental principle of Neolithic architecture, Ancient Greek architecture and Ancient Egyptian architecture. Other trabeated styles are the Persian, Lycian, Japanese, traditional Chinese, and ancient Chinese architecture, especially in northern China, and nearly all the Indian styles. The traditions are represented in North and Central America by Mayan architecture, and in South America by Inca architecture . EX. Stonehenge, an example of Neolithic architecture post and lintel construction. Post and lintel construction of the World Heritage Monument site Airavatesvara Temple, India

DOME A dome is an element of architecture that resembles the hollow upper half of a sphere. Dome structures made of various materials have a long architectural lineage extending into prehistory. A dome can be thought of as an arch which has been rotated around its central vertical axis. Thus domes, like arches, have a great deal of structural strength when properly built and can span large open spaces without interior supports. Corbel domes achieve their shape by extending each horizontal layer of stones inward slightly farther than the previous, lower, one until they meet at the top. These are sometimes called false domes. True, or real, domes are formed with increasingly inward-angled layers of voussoirs which have ultimately turned 90 degrees from the base of the dome to the top. When the base of the dome does not match the plan of the supporting walls beneath it (for example, a circular dome on a square bay), techniques are employed to transition between the two. The simplest technique is to use diagonal lintels across the corners of the walls to create an octagonal base. Another is to use arches called squinchs to span the corners, which can support more weight. The invention of pendentives superseded the squinch technique. Pendentives are triangular sections of a sphere used to transition from the flat surfaces of supporting walls to the round base of a dome. Domes can be divided into two kinds: simple and compound, depending on the use of pendentives. [3] In the case of the simple dome, the pendentives are part of the same sphere as the dome itself; however, such domes are rare. In the case of the more common compound dome, the pendentives are part of the surface of a larger sphere below that of the dome itself and form a circular base for either the dome or a drum section. Drums, also called tholobates or tambours, are cylindrical or polygonal walls supporting a dome which may contain windows. Domes have been constructed from a wide variety of building materials over the centuries: from mud to stone, wood, brick, concrete, metal, glass and plastic. EX. Dome of St. Peter's Basilica in Rome crowned by a cupola. Designed primarily by Michelangelo, the dome was not completed until 1590 The dome of Hagia Sophia, or Church of the Holy Wisdom, in Istanbul, Turkey

Saint Basil's Cathedral (1555–61) inMoscow, Russia. Its distinctive onion domes date to the 1680s. VAULT A Vault (French voûte, from Italian volta) is an architectural term for an arched form used to provide a space with a ceiling or roof. [1] The parts of a vault exert lateral thrust that require a counter resistance. When vaults are built underground, the ground gives all the resistance required. However, when the vault is built above ground, various replacements are employed to supply the needed resistance. An example is the thicker walls used in the case of barrel or continuous vaults. Buttresses are used to supply resistance when intersecting vaults are employed. The simplest kind of vault is the barrel vault (also called a wagon or tunnel vault) which is generally semicircular in shape. The barrel vault is a continuous arch, the length being greater than its diameter. As in building an arch, a temporary support is needed while rings ofvoussoirs are constructed and the rings placed in position. Until the topmost voussoir, the keystone, is positioned the vault is not self-supporting. Where timber is easily obtained, this temporary support is provided by centering consisting of a framed truss with a semicircular or segmental head, which supports the voussoirs until the ring of the whole arch is completed. With a barrel vault, the centering can then be shifted on to support the next rings. EX. Hagia Sophia inIstanbul. Reims Cathedral, France Gothic rib-vault ceiling of the Saint-Séverin church in Paris. VOLUTES A volute is a spiral scroll-like ornament that forms the basis of the Ionic order, found in the capital of the Ionic column. It was later incorporated into Corinthian order and Composite column capitals. Four are normally to be found on an Ionic capital, eight on Composite capitals and smaller versions (sometimes called helix) on the Corinthian capital. The word derives from the Latin voluta ("scroll"). It has been suggested that the ornament was inspired by the curve of a ram's horns, or perhaps was derived from the natural spiral of the ovule of a common species of clover native to Greece. Alternatively, it may simply be of geometrical origins. The ornament is used as an element of Renaissance and Baroque architecture and is a common decoration in furniture design, silver and ceramics. A method of drawing the complex geometry was devised by the ancient Roman architect Vitruvius from classical buildings and structures. EX. Volute of a Roman capital. From Julien David LeRoy, Les ruines plus beaux des monuments de la Grèce, Paris, 1758 (Plate XX) IONIC ORDER The Ionic order (Greek: Ιωνικός ρυθμός) forms one of the three orders or organizational systems of classical architecture, the other two canonic orders being the Doric and the Corinthian. (There are two lesser orders, the stocky Tuscan order and the rich variant of Corinthian, the Composite order, added by 16th-century Italian architectural theory and practice.)

The Ionic capital is characterized by the use of volutes. The Ionic columns normally stand on a base which separates the shaft of the column from thestylobate or platform; The cap is usually enriched with egg-and-dart. The Ionic order came from eastern Greece, where its origins are entwined with the similar but little known Aeolic order. It is distinguished by slender, fluted pillarswith a large base and two opposed volutes (also called scrolls) in the echinus of the capital. The echinus itself is decorated with an egg-and-dart motif. The Ionic shaft comes with four more flutes than the Doric counterpart (totalling 24). The Ionic base has two convex moldings called tori which are separated by a scotia. The Ionic order is also marked by an entasis, a curved tapering in the column shaft. A column of the ionic order is nine times its lower diameter. The shaft itself is eight diameters high. The architrave of the entablature commonly consists of three stepped bands (fasciae). The frieze comes without the Doric triglyph and metope. The frieze sometimes comes with a continuous ornament such as carved figures instead.

EX. Julien David LeRoy,Les ruines plus beaux des monuments de la Grèce Paris, 1758 (Plate XX) Scamozzian Ionic capitals on Castle Coole portico

DORIC ORDER

The Doric order originated on the mainland and western Greece. It is the simplest of the orders, characterized by short, faceted, heavy columns with plain, roundcapitals (tops) and no base. With a height that is only four to eight times its diameter, the columns are the most squat of all orders. The shaft of the Doric order is channeled with 20 flutes. The capital consists of a necking which is of a simple form. The echinus is convex and the abacus is square. Above the capital is a square abacus connecting the capital to the entablature. The Entablature is divided into three horizontal registers, the lower part of which is either smooth or divided by horizontal lines. The upper half is distinctive for the Doric order. The frieze of the Doric entablature is divided into triglyphs and metopes. A triglyph is a unit consisting of three vertical bands which are separated by grooves. Metopes are the plain or carved reliefs between two triglyphs. The Greek forms of the Doric order come without an individual base. They instead are placed directly on the stylobate. Later forms, however, came with the conventional base consisting of a plinth and a torus. The Roman versions of the Doric order have smaller proportions. As a result they appear lighter than the Greek orders. Ex. The Doric order of theParthenon CORINTHIAN ORDER

The Corinthian order is the latest of the three principal classical orders of ancient Greek and Roman architecture. The other two are the Doric order which was the earliest, followed by the Ionic order. When classical architecture was revived during the Renaissance, two more orders were added to the canon, the Tuscan order and the Composite order. The Corinthian, with its offshoot the Composite, is stated to be the most ornate of the orders, characterized by slender fluted columns and elaborate capitals decorated with acanthus leaves and scrolls. The name "Corinthian" is derived from the ancient Greek city of Corinth, although the style had its own model in Roman practice, following precedents set by the Temple of Mars Ultor in the Forum of Augustus (c. 2 AD). It was employed in southern Gaul at the Maison Carrée, Nîmes (illustration, below) and at the comparable podium temple at Vienne. Other prime examples noted by Mark Wilson Jones are the lower order of the Basilica Ulpia and the arch at Ancona (both of the reign of Trajan, 98–117 AD) the "column of Phocas" (re-erected in Late Antiquity but 2nd century in origin), and the "Temple of Bacchus" at Baalbek (c. 150 AD)

The Corinthian order is the most ornate of the Greek orders, characterized by a slender fluted column having an ornate capital decorated with two rows of acanthus leaves and four scrolls. It is commonly regarded as the most elegant of the three orders. The shaft of the Corinthian order has 24 flutes. The column is commonly ten diameters high. The Roman writer Vitruvius credited the invention of the Corinthian order to Callimachus, a Greek sculptor of the 5th century BC. The oldest known building built according to this order is the Choragic Monument of Lysicrates in Athens, constructed from 335 to 334 BC. The Corinthian order was raised to rank by the writings of Vitruvius in the 1st century BC. EX. Corinthian capital at the Getty Villa, Malibu, California Maison Carrée, Nîmes, France, 14 BCE Library of Hadrian, Athens COLUMN Column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. The term column applies especially to a large round support with a capital and base[1] and made of stone, or appearing to be so. A small wooden or metal support is typically called a post, and supports with a rectangular or other non-round section are usually called piers. For the purpose of wind or earthquake engineering, columns may be designed to resist lateral forces. Other compression members are often termed "columns" because of the similar stress conditions. Columns are frequently used to support beams or arches on which the upper parts of walls or ceilings rest. In architecture, "column" refers to such a structural element that also has certain proportional and decorative features. A column might also be a decorative element not needed for structural purposes; many columns are "engaged", that is to say form part of a wall. EX. National Capitol Columns at the United States National Arboretum in Washington, D.C. Columns found at the Temple of Apollo in Delphi Church of San Prospero, Reggio Emilia,Italy

SHAFT The shaft is long and narrow and is the main support of a column. It is found between the capital and the base and is either tapered so that it is thicker near the bottom and thinner as it reaches the top. The shaft of a column can also be fluted or un-fluted. CAPITAL The capital is found at the top of the shaft and is the decorative element of the column. It divides the impost block, also called the abacus, from the shaft. Columns are identifiable by their capital which are either plain, have acanthus, olive or laurel leaves or scrolls. Some capitals also consist of separate parts. BASE (PLINTH) The plinth is the foot, or the base of the column that rests directly on the stylobate. Plinths differ in design depending on the type of column. Plinths are also used as a platform for different objects such as a pedestal, statue or monument. ZIGGURAT Ziggurats (/ˈzɪɡʊˌræt/, Akkadian ziqqurat, D-stem of zaqāru "to build on a raised area") were massive structures built in the ancientMesopotamian valley and western Iranian plateau, having the form of a terraced step pyramid of successively receding stories or levels. Ziggurats were built by the Sumerians, Babylonians, Elamites, Akkadians, and Assyrians for local religions. Each ziggurat was part of a temple complex which included other buildings. The precursors of the ziggurat were raised platforms that date from the Ubaid period during the fourth millennium BC. The earliest ziggurats began near the end of the Early Dynastic Period. The latest Mesopotamian ziggurats date from the 6th century BC. Built in receding tiers upon a rectangular, oval, or square platform, the ziggurat was a pyramidal structure with a flat top. Sun-baked bricks made up the core of the ziggurat with facings of fired bricks on the outside. The facings were often glazed in different colors and may have had astrological significance. Kings sometimes had their names engraved on these glazed bricks. The number of tiers ranged from two to seven. It is assumed that they had shrines at the top, but there is no archaeological evidence for this and the only textual evidence is from Herodotus.[3] Access to the shrine would have been by a series of ramps on one side of the ziggurat or by a spiral ramp from base to summit. The Mesopotamian ziggurats were not places for public worship or ceremonies. They were believed to be dwelling places for the gods and each city had its own patron god. Only priests were permitted on the ziggurat or in the rooms at its base, and it was their responsibility to care for the gods and attend to their needs. The priests were very powerful members of Sumerian society. EX. Marduk ziggurat, or Etemenanki, of ancient Babylon White Temple of Uruk, in ancient Sumer. Chogha Zanbil in western Iran SKYSCARPER A skyscraper is a tall, continuously habitable building of many storeys, usually designed for office and commercial use. There is no official definition or height above which a building may be classified

as a skyscraper. One common feature of skyscrapers is having a steel framework that supports curtain walls. These curtain walls either bear on the framework below or are possibly suspended from the framework above, rather than 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 ofreinforced concrete. Modern skyscrapers' walls are not load-bearing, and most skyscrapers are characterized by large surface areas of windows made possible by the concept of steel frame and curtain walls. However, skyscrapers can have curtain walls that mimic conventional walls and a small surface area of windows. Skyscrapers since the 1960s use the tubular designs, innovated by Bangladeshi-American structural engineer Fazlur Rahman Khan. This engineering principle makes the buildings structurally more efficient and stronger. It reduces the usage of material (economically much more efficient), while simultaneously allows the buildings to reach greater heights. It allows fewer interior columns, and so creates more usable floor space. It further enables buildings to take on various shapes. There are several variations of the tubular design; these structural systems are fundamental to tall building design today.Other pioneers include Hal Iyengar, William LeMessurier, etc. Cities have experienced a huge surge in skyscraper construction. Today, skyscrapers are an increasingly common sight where land is expensive, as in the centres of big cities, because they provide such a high ratio of rentable floor space per unit area of land. They are built not just for economy of space; like temples and palaces of the past, skyscrapers are considered symbols of a city's economic power. Not only do they define the skyline, they help to define the city's identity. In some cases, exceptionally tall skyscrapers have been built not out of necessity, but to help define the city's identity and presence or power as a city. EX. The Two Towers of Bologna in the 12th century reached 97.2 m (319 ft) in height. The Burj Khalifa, tallest skyscraper in the world since 2010.