A column in structural engineering Structural engineering is a field of engineering dealing with the analysis and design of structures that support or resist loads. Structural engineering is usually considered a specialty within civil engineering, but it can also be studied in its own right. Structural engineers are most commonly involved in the design of buildings and large is a vertical structural element that transmits, through compression Physical compression is the result of the subjection of a material to compressive stress, resulting in reduction of volume. The opposite of compression is tension. In simpler words, Compression is a pushing force, the weight of the structure above to other structural elements below. For the purpose of wind Wind engineering is a field of structural engineering devoted to the analysis of wind effects on the natural or built environment to protect it from possible damage. It includes strong winds which may cause discomfort as well as extreme winds such as tornadoes, hurricanes and storms which may cause widespread destruction or earthquake engineering Earthquake engineering is the study of the behavior of buildings and structures subject to seismic loading. It is a subset of both structural and civil engineering, columns may be designed to resist lateral forces. Other compression members For a compression member, such as a column, the principal stress comes mainly from axial forces, that is forces that fall along one line, usually the centerline are often termed "columns" because of the similar stress conditions. Columns are frequently used to support beams A beam is a structural element that is capable of withstanding load primarily by resisting bending. The bending force induced into the material of the beam as a result of the external loads, own weight and external reactions to these loads is called a bending moment or arches An arch is a structure that spans a space while supporting weight . Arches appeared as early as the 2nd millennium BC in Mesopotamian 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 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 or triumphant feature but need not be supporting any structure e.g. a statue on top.

History

In the architecture of ancient Egypt Ancient Egypt was an ancient civilization of eastern North Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. The civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh, and it developed over the next three millennia. Its history as early as 2600 BC Categories: 3rd millennium BC | 26th century BC | Centuries the architect Imhotep Imhotep (sometimes spelled Immutef, Im-hotep, or Ii-em-Hotep; called Imuthes by the Greeks), fl. 27th century BC (2655-2600 BC) (Egyptian ii-m-ḥtp *jā-im-ḥatāp meaning "the one who comes in peace") was an Egyptian polymath, who served under the Third Dynasty king, Djoser, as chancellor to the pharaoh and high priest of the sun god made use of stone columns whose surface was carved to reflect the organic form of bundled reeds; in later Egyptian architecture faceted cylinders were also common.

Some of the most elaborate columns in the ancient world were those of Persia The Achaemenid Empire , also known as the Persian Empire, was the successor state of the Median Empire, ruling over significant portions of what would become Greater Iran. The Persian and the Median Empire taken together are also known as the Medo-Persian Empire, which encompassed the combined territories of several earlier empires especially the massive stone columns erected in Persepolis Persepolis was the ceremonial capital of the Achaemenid Empire (ca. 550-330 BCE). Persepolis is situated 70 km northeast of the modern city of Shiraz in the Fars Province of modern Iran. In contemporary Persian, the site is known as Takht-e Jamshid (Throne of Jamshid) and Parseh. The earliest remains of Persepolis date from around 515 BCE. To the. They included double-bull structures in their capitals In several traditions of architecture including Classical architecture, the capital forms the crowning member of a column or a pilaster. The capital projects on each side as it rises, to support the abacus and unite the form of the latter (normally square) with the circular shaft of the column. The bulk of the capital may either be convex, as in. The Hall of Hundred Columns The Apadana is the name of the great audience hall and portico at Persepolis and Susa. It belongs to the oldest building phase of the city of Persepolis, built during the first half of the 5th century BC as part of the original design by Darius the Great, its construction completed by Xerxes I. Modern scholarships "demonstrates the at Persepolis, measuring 70 × 70 meters was built by the Achaemenid The Achaemenid Empire , also known as the Persian Empire, was the successor state of the Median Empire, ruling over significant portions of what would become Greater Iran. The Persian and the Median Empire taken together are also known as the Medo-Persian Empire, which encompassed the combined territories of several earlier empires king Darius I (524–486 BC). Many of the ancient Persian columns are standing, some being more than 30 meters tall.^{[citation needed]}

The Greeks pioneered the use of the classical orders (Doric, Ionic, Corinthian) which was expanded by the Romans to include the Tuscan and Composite styles.

The impost (or pier) is the topmost member of a column. The bottom-most part of the arch, called the springing, rests on the impost.

Structure

Early columns were constructed of stone, some out of a single piece of stone, usually by turning on a lathe-like apparatus. Single-piece columns are among the heaviest stones used in architecture. Other stone columns are created out of multiple sections of stone, mortared or dry-fit together. In many classical sites, sectioned columns were carved with a center hole or depression so that they could be pegged together, using stone or metal pins. The design of most classical columns incorporates entasis 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 upwards. In the Hellenistic period some colums with entasis are cylindrical in their lower parts. Some Roman columns are ' (the inclusion of a slight outward curve in the sides) plus a reduction in diameter along the height of the column, so that the top is as little as 83% of the bottom diameter. This reduction mimics the parallax effects which the eye expects to see, and tends to make columns look taller and straighter than they are while entasis adds to that effect.

Modern columns are constructed out of steel, poured or precast concrete, or brick. They may then be clad in an architectural covering (or veneer), or left bare.

Equilibrium, instability, and loads

As the axial load on a perfectly straight slender column with elastic material properties is increased in magnitude, this ideal column passes through three states: stable equilibrium, neutral equilibrium, and instability. The straight column under load is in stable equilibrium if a lateral force, applied between the two ends of the column, produces a small lateral deflection which disappears and the column returns to its straight form when the lateral force is removed. If the column load is gradually increased, a condition is reached in which the straight form of equilibrium becomes so-called neutral equilibrium, and a small lateral force will produce a deflection that does not disappear and the column remains in this slightly bent form when the lateral force is removed. The load at which neutral equilibrium of a column is reached is called the critical or buckling In engineering, buckling is a failure mode characterized by a sudden failure of a structural member subjected to high compressive stresses, where the actual compressive stress at the point of failure is less than the ultimate compressive stresses that the material is capable of withstanding. This mode of failure is also described as failure due to load. The state of instability is reached when a slight increase of the column load causes uncontrollably growing lateral deflections leading to complete collapse.

For an axially loaded straight column with any end support conditions, the equation of static equilibrium, in the form of a differential equation, can be solved for the deflected shape and critical load of the column. With hinged, fixed or free end support conditions the deflected shape in neutral equilibrium of an initially straight column with uniform cross section throughout its length always follows a partial or composite sinusoidal curve shape, and the critical load is given by

where E = modulus of elasticity of the material, I_min = the minimal moment of inertia of the cross section, and L = actual length of the column between its two end supports. A variant of (1) is given by

where r = radius In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter of gyration of [column]cross-section which is equal to the square root of (I/A), K = ratio of the longest half sine In mathematics, the trigonometric functions are functions of an angle. They are used to relate the angles of a triangle to the lengths of the sides of a triangle. Trigonometric functions are important in the study of triangles and modeling periodic phenomena, among many other applications wave to the actual column length, and KL = effective length (length of an equivalent hinged-hinged column). From Equation (2) it can be noted that the buckling strength of a column is inversely proportional to the square of its length.

When the critical stress, F_cr (F_cr =P_cr/A, where A = cross-sectional area of the column), is greater than the proportional limit of the material, the column is experiencing inelastic buckling. Since at this stress the slope of the material's stress-strain curve, E_t (called the tangent In geometry, the tangent line to a curve at a given point is the straight line that "just touches" the curve at that point (in the sense explained more precisely below). As it passes through the point where the tangent line and the curve meet, or the point of tangency, the tangent line is "going in the same direction" as the modulus), is smaller than that below the proportional limit, the critical load at inelastic buckling is reduced. More complex formulas and procedures apply for such cases, but in its simplest form the critical buckling load formula is given as Equation (3),

where E_t = tangent modulus at the stress F_cr

A column with a cross section that lacks symmetry may suffer torsional buckling (sudden twisting) before, or in combination with, lateral buckling. The presence of the twisting deformations renders both theoretical analyses and practical designs rather complex.

Eccentricity of the load, or imperfections such as initial crookedness, decreases column strength. If the axial load on the column is not concentric, that is, its line of action is not precisely coincident with the centroidal axis of the column, the column is characterized as eccentrically loaded. The eccentricity of the load, or an initial curvature, subjects the column to immediate bending. The increased stresses due to the combined axial-plus-flexural stresses result in a reduced load-carrying ability. All concrete and reinforced concrete columns, produced using usual heavy concrete consolidated by vibration have inhomogeneity of at least strength characteristics of concrete by volume. Distribution of concrete strength for monolithic vertical elements (columns) investigated and presented in the paper of M. Bulavytskyi "Concrete Inhomogeneity of Vertical Cast-In-Place Elements In Skeleton-Type Buildings" (Ukraine http://www.concreteresearch.org).

Extensions

When a column is too long to be built or transported in one piece, it has to be extended or spliced at the construction site. A reinforced concrete column is extended by having the steel reinforcing bars protrude a few inches or feet above the top of the concrete, then placing the next level of reinforcing bars to overlap, and pouring the concrete of the next level. A steel column is extended by welding or bolting splice plates on the flanges and webs or walls of the columns to provide a few inches or feet of load transfer from the upper to the lower column section. A timber column is usually extended by the use of a steel tube or wrapped-around sheet-metal plate bolted onto the two connecting timber sections.

Foundations

A column that carries the load down to a foundation must have means to transfer the load without overstressing the foundation material. Reinforced concrete and masonry columns are generally built directly on top of concrete foundations. A steel column, when seated on a concrete foundation, must have a base plate to spread the load over a larger area and thereby reduce the bearing pressure. The base plate is a thick rectangular steel plate usually welded to the bottom end of the column.

Classical orders

The Roman Ancient Rome was a civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC. Located along the Mediterranean Sea, it became one of the largest empires in the ancient world author Vitruvius Marcus Vitruvius Pollio was a Roman writer, architect and engineer (possibly praefectus fabrum during military service or praefect architectus armamentarius of the apparitor status group), active in the 1st century BC. By his own description Vitruvius served as a Ballista (artilleryman), the third class of arms in the military offices. He likely, relying on the writings (now lost) of Greek Ancient Greece is the civilization belonging to the period of Greek history lasting from the Archaic period of the 8th to 6th centuries BC to 146 BC and the Roman conquest of Greece after the Battle of Corinth. At the center of this time period is Classical Greece, which flourished during the 5th to 4th centuries BC, at first under Athenian authors, tells us that the ancient Greeks Ancient Greece is the civilization belonging to the period of Greek history lasting from the Archaic period of the 8th to 6th centuries BC to 146 BC and the Roman conquest of Greece after the Battle of Corinth. At the center of this time period is Classical Greece, which flourished during the 5th to 4th centuries BC, at first under Athenian believed that their Doric order developed from techniques for building in wood in which the earlier smoothed tree trunk was replaced by a stone cylinder.

Doric order

The Doric order The Doric order was one of the three orders or organizational systems of Ancient Greek or classical architecture; the other two canonical orders were the Ionic and the Corinthian is the oldest and simplest of the classical orders. It is composed of a vertical cylinder A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given straight line, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder. The surface area and the volume of a cylinder have been known since that is wider at the bottom. It generally has neither a base nor a detailed capital In several traditions of architecture including Classical architecture, the capital forms the crowning member of a column or a pilaster. The capital projects on each side as it rises, to support the abacus and unite the form of the latter (normally square) with the circular shaft of the column. The bulk of the capital may either be convex, as in. It is instead often topped with an inverted frustum In geometry, a frustum is the portion of a solid (normally a cone or pyramid) which lies between two parallel planes cutting it of a shallow cone or a cylindrical band of carvings. It is often referred to as the masculine order because it is represented in the bottom level of the Colosseum The Colosseum or Roman Coliseum, originally the Flavian Amphitheatre , is an elliptical amphitheatre in the center of the city of Rome, Italy, the largest ever built in the Roman Empire. It is considered one of the greatest works of Roman architecture and Roman engineering and the Parthenon The Parthenon is a temple in the Athenian Acropolis, Greece, dedicated to of the Greek goddess Athena, whom the people of Athens considered their protector. Its construction began in 447 BC and was completed in 438 BC, although decorations of the Parthenon continued until 431 BC. It is the most important surviving building of Classical Greece,, and was therefore considered to be able to hold more weight. The height-to-thickness ratio is about 8:1. The shaft of a Doric Column is always fluted.

The Greek Doric, developed in the western Dorian region of Greece, is the heaviest and most massive of the orders. It rises from the stylobate without any base; it is from four to six times as tall as its diameter; it has twenty broad flutes; the capital consists simply of a banded necking swelling out into a smooth echinus , which carries a flat square abacus; the Doric entablature is also the heaviest, being about one-fourth the height column. The Greek Doric order was not used after c. 100 B.C. until its “rediscovery” in the mid-eighteenth century.

Tuscan order

The Tuscan order Among canon of classical orders of classical architecture, the Tuscan order's place is due to the influence of the Italian Sebastiano Serlio, who meticulously described the five orders including a "Tuscan order", "the solidest and least ornate", in his fourth book of Regole generalii di Architettura... sopra le cinque maniere, also known as Roman Doric, is also a simple design, the base and capital both being series of cylindrical disks of alternating diameter. The shaft is almost never fluted. The proportions vary, but are generally similar to Doric columns. Height to width ratio is about 7:1.

Ionic order

The Ionic The Ionic order 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.) column is considerably more complex than the Doric or Tuscan. It usually has a base and the shaft is often fluted (it has grooves carved up its length). On the top is a capital in the characteristic shape of a scroll A scroll is a roll of papyrus, parchment, or paper which has been written, drawn or painted upon for the purpose of transmitting information or using as a decoration. It is distinguished from a roll by virtue of being intended for repeated use rather than continuous, but once-only use of the roll, called a volute 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 on the Corinthian capital, or scroll, at the four corners. The height-to-thickness ratio is around 9:1. Due to the more refined proportions and scroll capitals, the Ionic column is sometimes associated with academic buildings.

Corinthian order

The Corinthian order is named for the Greek city-state of Corinth, to which it was connected in the period. However, according to the architectural historian Vitruvius, the column was created by the sculptor Callimachus, probably an Athenian, who drew acanthus leaves growing around a votive basket. In fact, the oldest known Corinthian capital was found in Bassae, dated at 427 BC. It is sometimes called the feminine order because it is on the top level of the Colosseum and holding up the least weight, and also has the slenderest ratio of thickness to height. Height to width ratio is about 10:1.

Composite order

The Composite order draws its name from the capital being a composite of the Ionic and Corinthian capitals. The acanthus of the Corinthian column already has a scroll-like element, so the distinction is sometimes subtle. Generally the Composite is similar to the Corinthian in proportion and employment, often in the upper tiers of colonnades. Height to width ratio is about 11:1 or 12:1.

Solomonic

Solomonic columns were inventions of Baroque architects in Europe. They were not used in antiquity, but were called “Solomonic” by baroque architects because they were based on a description of columns in the great temple of King Solomon in the Old Testament. A Solomonic column begins on a base and ends in a capital, just like a classical column, but the shaft twists around the usual parameters of a column, producing a dramatic, serpentine effect of movement. The most famous use of Solomonic columns is in the baldacchino designed by Bernini for Saint Peter’s Basilica in the Vatican City.

Notable columns

• Alexander Column
• Ashoka Column
• Berlin victory column
• Holy Trinity Column in Olomouc
• Iron Column
• Monument to the Great Fire of London
• Nelson's Column
• Rostral Columns
• Sigismund's Column
• Trajan's Column
• Brock's Monument

See also

• Buckling
• Capital
• Colonnade
• Composite Order
• Corinthian Order
• Doric Order
• Entasis
• Ionic Order
• Marian and Holy Trinity columns
• Persian column
• Pier (architecture)
• Pilaster
• Spur (architecture)
• Stanchion
• Tuscan Order

Categories: Columns and entablature | Egyptian artefact types | Architectural elements | Structural system | Earthquake engineering

See Also:

What Links Here:

Recently Viewed Pages:

• Health: Addictions: Substance Abuse: Support Groups: Celebrate Recovery: Directory
• Sitemap
• Home
• Support Group: News
• About Us
• Dictionary
• Celebrate Recovery
• Celebrate Recovery: News
• Society: Support Groups: Codependency: Directory
• Infertility

Most Popular Pages:

• Home
• Departmentalization
• Impalement: Encyclopedia
• Departmentalization: Encyclopedia
• Society: Support Groups: Codependency: Directory
• Summa: Answers
• Column: Web Search
• Search Terms
• Yolk Sac: Blogs
• Directory Sites

Related 'Column' Searches: