Entasis

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Diagram of a Corinthian column showing a visible entasis bulge at "D" Korinthische Saulenordnung Entasis2.png
Diagram of a Corinthian column showing a visible entasis bulge at "D"

In architecture, entasis is the application of a convex curve to a surface for aesthetic purposes. Its best-known use is in certain orders of Classical columns that curve slightly as their diameter is decreased from the bottom upward. It also may serve an engineering function regarding strength.

Architecture The product and the process of planning, designing and constructing buildings and other structures.

Architecture is both the process and the product of planning, designing, and constructing buildings or any other structures. Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements.

Classical architecture Architectural style

Classical architecture usually denotes architecture which is more or less consciously derived from the principles of Greek and Roman architecture of classical antiquity, or sometimes even more specifically, from the works of Vitruvius. Different styles of classical architecture have arguably existed since the Carolingian Renaissance, and prominently since the Italian Renaissance. Although classical styles of architecture can vary greatly, they can in general all be said to draw on a common "vocabulary" of decorative and constructive elements. In much of the Western world, different classical architectural styles have dominated the history of architecture from the Renaissance until the second world war, though it continues to inform many architects to this day.

Column structural element sustaining the weight of a building

A 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 a base or pedestal which is 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.

Contents

Etymology

The word we apply to the design principle is used by the Roman architectural historian Vitruvius, [1] and derives from the Greek word εντείνω (enteino), "to stretch or strain tight". Creating the illusion of greater strength or perception of height may have been an objective in the application of entasis.

Vitruvius Roman writer, architect and engineer

Marcus Vitruvius Pollio, commonly known as Vitruvius, was a Roman author, architect, civil engineer and military engineer during the 1st century BC, known for his multi-volume work entitled De architectura. His discussion of perfect proportion in architecture and the human body led to the famous Renaissance drawing by Leonardo da Vinci of Vitruvian Man.

Examples

Examples of this design principle may be found in cultures throughout the world, from ancient times to contemporary architecture. The first known use of entasis was in the construction of Egyptian pyramids.

Egypt Country spanning North Africa and Southwest Asia

Egypt, officially the Arab Republic of Egypt, is a country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba and the Red Sea to the east, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, across the Red Sea lies Saudi Arabia, and across the Mediterranean lie Greece, Turkey and Cyprus, although none share a land border with Egypt.

Egyptian pyramids Ancient pyramid-shaped masonry structures located in Egypt

The Egyptian pyramids are ancient pyramid-shaped masonry structures located in Egypt. As of November 2008, sources cite either 118 or 138 as the number of identified Egyptian pyramids. Most were built as tombs for the country's pharaohs and their consorts during the Old and Middle Kingdom periods.

It also may be observed among Classical period Greek column designs, built a thousand years later, for example, in the Doric-order temples in Segesta, Selinus, Agrigento, and Paestum.

Segesta Ancient city

Segesta was one of the major cities of the Elymians, one of the three indigenous peoples of Sicily. The other major cities of the Elymians were Eryx and Entella. It is located in the northwestern part of Sicily in Italy, near the modern commune of Calatafimi-Segesta in the province of Trapani. The hellenization of Segesta happened very early and had a profound effect on its people.

Agrigento Comune in Sicily, Italy

Agrigento is a city on the southern coast of Sicily, Italy and capital of the province of Agrigento. It was one of the leading cities of Magna Graecia during the golden age of Ancient Greece with population estimates in the range of 200,000 to 800,000 before 406 BC.

Paestum ancient Greek city in todays Capaccio Paestum, Italy

Paestum was a major ancient Greek city on the coast of the Tyrrhenian Sea in Magna Graecia. The ruins of Paestum are famous for their three ancient Greek temples in the Doric order, dating from about 600 to 450 BC, which are in a very good state of preservation. The city walls and amphitheatre are largely intact, and the bottom of the walls of many other structures remain, as well as paved roads. The site is open to the public, and there is a modern national museum within it, which also contains the finds from the associated Greek site of Foce del Sele.

It was used less frequently in Hellenistic and Roman period architecture.[ citation needed ] The Roman temples built during these periods were higher than those of the Greeks, with longer and thinner columns.

Hellenistic period Period of ancient Greek and Mediterranean history

The Hellenistic period covers the period of Mediterranean history between the death of Alexander the Great in 323 BC and the emergence of the Roman Empire as signified by the Battle of Actium in 31 BC and the subsequent conquest of Ptolemaic Egypt the following year. The Ancient Greek word Hellas is the original word for Greece, from which the word Hellenistic was derived.

Ancient Rome History of Rome from the 8th-century BC to the 5th-century

In historiography, ancient Rome is Roman civilization from the founding of the Italian city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD, encompassing the Roman Kingdom, Roman Republic and Roman Empire until the fall of the western empire. The civilization began as an Italic settlement in the Italian Peninsula, conventionally founded in 753 BC, that grew into the city of Rome and which subsequently gave its name to the empire over which it ruled and to the widespread civilisation the empire developed. The Roman Empire expanded to become one of the largest empires in the ancient world, though still ruled from the city, with an estimated 50 to 90 million inhabitants ) and covering 5.0 million square kilometres at its height in AD 117.

Chinese carpenters of the Song Dynasty followed designs in the AD 1103 Yingzao Fashi (Treatise on Architectural Methods or State Building Standards) that specified straight columnns or those with an entasis on the upper third of the shaft. [2]

<i>Yingzao Fashi</i> book by Jie Li

The Yingzao Fashi is a technical treatise on architecture and craftsmanship written by the Chinese author Li Jie, the Directorate of Buildings and Construction during the mid Song Dynasty of China. A promising architect, he revised many older treatises on architecture from 1097 to 1100. By 1100, he had completed his own architectural work, which he presented to Emperor Zhezong of Song. The emperor's successor, Emperor Huizong of Song, had the book published in 1103 in order to provide a unified set of architectural standards for builders, architects, and literate craftsmen as well as for the engineering agencies of the central government. With his book becoming a noted success, Li Jie was promoted by Huizong as the Director of Palace Buildings. Thereafter, Li became well known for his oversight in the construction of administrative offices, palace apartments, gates and gate-towers, the ancestral temple of the Song Dynasty, along with numerous Buddhist temples. In 1145, a second edition of Li's book was published by Wang Huan. Between 1222-1233, a third printing was published. This edition, published in Pingjiang, was later handcopied into the Yongle Encyclopedia and Siku Quanshu. In addition, a number of handcopied editions were made for private libraries. One of these handcopies of the Pingjiang edition was rediscovered in 1919 and printed as facsimile in 1920.

Noted architects, such as the Renaissance master Andrea Palladio, also used entasis in the designs of their buildings.

Entasis was often a feature of Inca walls and double-jamb doorways, where they also act to counteract the optical illusion that would make the doorway appear narrower in the middle of its slope, than it really would be. [3]

It also may be seen in the sloping or battered walls of some Tibetan monastery and fortress architecture, as well as that of Bhutan. The lower parts of these walls, approximately one third, have a slight inward curve, but the higher parts are straight. If one builds a whole wall as a straight, sloping surface, it appears to bulge outward. An example in Bhutan is the Dobji dzong. When some collapsed walls of the Punakha dzong were rebuilt, around 1996, this wisdom about optical perceptions appears to have been overlooked or unknown to the restorers and, the rebuilt walls, being straight, appear to bulge, according to Chris Butters, the author of The Treasure Revealer of Bhutan, Bibliotheca Himalayica, 1995.

Conjecture about Greek columns

Entasis columns at Horyu-ji, Japan Horyu-ji04s3200.jpg
Entasis columns at Hōryū-ji, Japan
The First Hera temple at Paestum, erroneously called a 'basilica' by eighteenth century authors, implemented entasis in its design PaestumBasilika.jpg
The First Hera temple at Paestum, erroneously called a 'basilica' by eighteenth century authors, implemented entasis in its design

The early Classical builders did not leave an explanation of their reasons for using entasis in their columns. Extensive conjecture about the purpose of its application by them exists.

An early view, often articulated and still widespread, espoused by Hero of Alexandria, is that entasis corrects the optical illusion of concavity in the columns that the fallible human eye would create if the correction were not made. [4]

External video
Nuvola apps kaboodle.svg smARThistory – Ancient Greek Temples at Paestum, Italy [5]

This view, however, does not explain the case of one well-known example, at Paestum on the western coast of Italy, where the entasis is so pronounced that it creates an obvious curvature, not an illusion of straightness.

Some descriptions of entasis, [6] state simply, that the technique was an enhancement applied to the more primitive conical columns to make them appear more substantial. Other descriptions argue that the technique emphasizes the substantiality of, not the columns, but rather, of some other part or of the building while being viewed as a whole. Yale architectural historian Vincent Scully argues that entasis emphasizes the weight of the roof of a building by making the building columns appear to bulge under the pressure distributed among them. Danish architect Steen Eiler Rasmussen believed that the effect represented strength by imitating the swelling of a strained muscle, [7] a theory that accords well with the etymology of the word, from the Greek meaning "to strain". [8]

It also has been argued that a "stunted cycloid" column that bulges in the middle is stronger structurally than is a column whose diameter changes according to a linear progression, therefore, having a sound engineering purpose. Because their discussion of the application of the principle has never been discovered, it is unknown, however, whether the early Greeks knew this. [9]

If the column originally was a cultural reference to, or analogous to, the palm tree, the "bulge" is an accurate representation of the palm tree trunk. That could account for the replication of an observed principle in nature that became a tradition.

Literature

Related Research Articles

Classical order Styles of classical architecture, most readily recognizable by the type of column employed

An order in architecture is a certain assemblage of parts subject to uniform established proportions, regulated by the office that each part has to perform. Coming down to the present from Ancient Greek and Ancient Roman civilization, the architectural orders are the styles of classical architecture, each distinguished by its proportions and characteristic profiles and details, and most readily recognizable by the type of column employed. The three orders of architecture—the Doric, Ionic, and Corinthian—originated in Greece. To these the Romans added, in practice if not in name, the Tuscan, which they made simpler than Doric, and the Composite, which was more ornamental than the Corinthian. The architectural order of a classical building is akin to the mode or key of classical music; the grammar or rhetoric of a written composition. It is established by certain modules like the intervals of music, and it raises certain expectations in an audience attuned to its language.

Corinthian order Latest of the three principal classical orders of ancient Greek and Roman architecture

The Corinthian order is the last developed 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 the most ornate of the orders. This architectural style is characterized by slender fluted columns and elaborate capitals decorated with acanthus leaves and scrolls. There are many variations.

Ancient Greek architecture

The architecture of ancient Greece is the architecture produced by the Greek-speaking people whose culture flourished on the Greek mainland, the Peloponnese, the Aegean Islands, and in colonies in Anatolia and Italy for a period from about 900 BC until the 1st century AD, with the earliest remaining architectural works dating from around 600 BC.

Doric order Order of ancient Greek and Roman architecture, with no base to the column, simple capital, and triglyphs on the frieze

The Doric order was one of the three orders of ancient Greek and later Roman architecture; the other two canonical orders were the Ionic and the Corinthian. The Doric is most easily recognized by the simple circular capitals at the top of columns. Originating in the western Dorian region of Greece, it is the earliest and in its essence the simplest of the orders, though still with complex details in the entablature above.

Ionic order Order of classical architecture characterized by the use of volutes in the capital and a base moulding on the columns

The Ionic order forms one of the three classical orders of classical architecture, the other two canonic orders being the Doric and the Corinthian. There are two lesser orders: the Tuscan, and the rich variant of Corinthian called the composite order, both added by 16th-century Italian architectural writers, based on Roman practice. Of the three canonic orders, the Ionic order has the narrowest columns.

Pilaster decorative architectural element giving the appearance of a supporting column

A pilaster is an architectural element in classical architecture used to give the appearance of a supporting column and to articulate an extent of wall, with only an ornamental function. It consists of a flat surface raised from the main wall surface, usually treated as though it were a column, with a capital at the top, plinth (base) at the bottom, and the various other column elements. In contrast to a pilaster, an engaged column or buttress can support the structure of a wall and roof above.

Dzong architecture kind of fortress

Dzong architecture is a distinctive type of fortress architecture found mainly in Bhutan and Tibetan areas of China. The architecture is massive in style with towering exterior walls surrounding a complex of courtyards, temples, administrative offices, and monks' accommodation.

Café wall illusion

The café wall illusion is a geometrical-optical illusion in which the parallel straight dividing lines between staggered rows with alternating black and white "bricks" appear to be sloped.

Mathematics and architecture

Mathematics and architecture are related, since, as with other arts, architects use mathematics for several reasons. Apart from the mathematics needed when engineering buildings, architects use geometry: to define the spatial form of a building; from the Pythagoreans of the sixth century BC onwards, to create forms considered harmonious, and thus to lay out buildings and their surroundings according to mathematical, aesthetic and sometimes religious principles; to decorate buildings with mathematical objects such as tessellations; and to meet environmental goals, such as to minimise wind speeds around the bases of tall buildings.

Capital (architecture) part of a column (architecture)

In architecture the capital or chapiter forms the topmost member of a column. It mediates between the column and the load thrusting down upon it, broadening the area of the column's supporting surface. The capital, projecting on each side as it rises to support the abacus, joins the usually square abacus and the usually circular shaft of the column. The capital may be convex, as in the Doric order; concave, as in the inverted bell of the Corinthian order; or scrolling out, as in the Ionic order. These form the three principal types on which all capitals in the classical tradition are based. The Composite order, established in the 16th century on a hint from the Arch of Titus, adds Ionic volutes to Corinthian acanthus leaves.

Ancient Greek temple structures built to house deity statues within Greek sanctuaries

Greek temples were structures built to house deity statues within Greek sanctuaries in ancient Greek religion. The temple interiors did not serve as meeting places, since the sacrifices and rituals dedicated to the respective deity took place outside them, within the wider precinct of the sanctuary, which might be large. Temples were frequently used to store votive offerings. They are the most important and most widespread building type in Greek architecture. In the Hellenistic kingdoms of Southwest Asia and of North Africa, buildings erected to fulfill the functions of a temple often continued to follow the local traditions. Even where a Greek influence is visible, such structures are not normally considered as Greek temples. This applies, for example, to the Graeco-Parthian and Bactrian temples, or to the Ptolemaic examples, which follow Egyptian tradition. Most Greek temples were oriented astronomically.

Cella inner chamber of a temple in classical architecture, or a shop facing the street in domestic Roman architecture

A cella or naos is the inner chamber of a temple in classical architecture, or a shop facing the street in domestic Roman architecture, such as a domus. Its enclosure within walls has given rise to extended meanings, of a hermit's or monk's cell, and since the 17th century, of a biological cell in plants or animals.

Triglyph Vertically channeled tablets of the Doric frieze in classical architecture

Triglyph is an architectural term for the vertically channeled tablets of the Doric frieze in classical architecture, so called because of the angular channels in them. The rectangular recessed spaces between the triglyphs on a Doric frieze are called metopes. The raised spaces between the channels themselves are called femur in Latin or meros in Greek. In the strict tradition of classical architecture, a set of guttae, the six triangular "pegs" below, always go with a triglyph above, and the pair of features are only found in entablatures of buildings using the Doric order. The absence of the pair effectively converts a building from being in the Doric order to being in the Tuscan order.

This page is a glossary of architecture.

Architecture of Bhutan

Bhutanese architecture consists of Dzong and everyday varieties. Dzongs in Bhutan were built as fortresses have served as religious and administrative centers since the 17th century. Secular lordly houses emerged as a distinct style in the late 19th century during a period of relative peace in Bhutan. Throughout its history, Bhutan has mainly followed the Tibetan tradition of Buddhist architecture.

Fluting (architecture)

Fluting in architecture consists of shallow grooves running along a surface.

Temple E (Selinus) building in Selinunte, Italy

Temple E at Selinus in Sicily is a Greek temple of the Doric order. It is found on the hill to the east of the city's acropolis. Temple E is also known as the Temple of Hera because an inscription found on a votive stela indicates that it was dedicated to Hera; however, some scholars argue that it must have been dedicated to Aphrodite on the basis of structural parallels. It was built towards the middle of the sixth century BC on top of the foundations of a more ancient building. It is the best conserved of the temples of Selinus but its present appearance is the result of anastylosis performed—controversially—in 1959, by the Italian archaeologist Jole Bovio Marconi.

Etruscan architecture

Etruscan architecture was created between about 700 BC and 200 BC, when the expanding civilization of ancient Rome finally absorbed Etruscan civilization. The Etruscans were considerable builders in stone, wood and other materials of temples, houses, tombs and city walls, as well as bridges and roads. The only structures remaining in quantity in anything like their original condition are tombs and walls, but through archaeology and other sources we have a good deal of information on what once existed.

References

Early fourteenth-century steeple of All Hallows' parish church, Gedling, Nottinghamshire, England, showing entasis of the spire Gedling Church Steeple - geograph.org.uk - 510263.jpg
Early fourteenth-century steeple of All Hallows' parish church, Gedling, Nottinghamshire, England, showing entasis of the spire
  1. Vitruvius. OnArchitecture. 3.3.13. Retrieved 21 April 2016.
  2. Liang, Sicheng, and Wilma Fairbank, ed. A pictorial history of Chinese architecture: a study of the development of its structural system and the evolution of its types. Cambridge, Massachusetts: MIT Press, 1984. 17.
  3. Protzen, Jean-Pierre. "Inca Architecture" in The Inca World, Laura Laurencich Minelli (ed). University of Oklahoma Press, 2000, pp. 196-197.
  4. Hero of Alexandria, Horoi ton geometrias onomaton, 135, 14: "Thus, since a cylindrical column would, when looked at, seem irregularly narrower in the middle, he makes this part of it wider" (translation given by Ralph Hancock, The Department of Greek and Latin at The Ohio State University)
  5. "Ancient Greek Temples at Paestum, Italy". smARThistory at Khan Academy. Retrieved December 18, 2012.
  6. entasis, article by Anthony Rich, Jun. B.A. of Caius College, Cambridge, on p461 of William Smith, D.C.L., LL.D.: A Dictionary of Greek and Roman Antiquities, John Murray, London, 1875.
  7. Steen Eiler Rasmussen, Experiencing Architecture, The MIT Press, 1959, p. 37.
  8. "entasis", Oxford English Dictionary, Second Edition 1989
  9. Peter Thompson et al., "Entasis: architectural illusion compensation, aesthetic preference or engineering necessity?", Journal of Vision, Volume 7, Number 9, ISSN 1534-7362 - abstract argues against traditional explanations for entasis and mentions possible engineering reasons