Column

Columns are frequently used to support beams or arches on which the upper parts of walls or ceilings rest.

In ancient Egyptian architecture as early as 2600 BC, the architect Imhotep made use of stone columns whose surface was carved to reflect the organic form of bundled reeds, like papyrus, lotus and palm.

They are composed of lotus (papyrus) stems which are drawn together into a bundle decorated with bands: the capital, instead of opening out into the shape of a bellflower, swells out and then narrows again like a flower in bud.

The base, which tapers to take the shape of a half-sphere like the stem of the lotus, has a continuously recurring decoration of stipules.

The Minoans employed columns to create large open-plan spaces, light-wells and as a focal point for religious rituals.

Being made of wood these early columns have not survived, but their stone bases have and through these we may see their use and arrangement in these palace buildings.

The Greeks developed the classical orders of architecture, which are most easily distinguished by the form of the column and its various elements.

The Hall of Hundred Columns at Persepolis, measuring 70 × 70 metres, was built by the Achaemenid king Darius I (524–486 BC).

[citation needed] Tall columns with bull's head capitals were used for porticoes and to support the roofs of the hypostylehall, partly inspired by the ancient Egyptian precedent.

Since the columns carried timber beams rather than stone, they could be taller, slimmer and more widely spaced than Egyptian ones.

In many classical sites, sectioned columns were carved with a centre hole or depression so that they could be pegged together, using stone or metal pins.

Doric flutes are connected at a sharp point where the fillets are located on Ionic and Corinthian order columns.

Scotiae could also occur in pairs, separated by a convex section called an astragal, or bead, narrower than a torus.

In the case of Doric columns, the capital usually consists of a round, tapering cushion, or echinus, supporting a square slab, known as an abax or abacus.

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

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 state of instability is reached when a slight increase of the column load causes uncontrollably growing lateral deflections leading to complete collapse.

where E = elastic modulus of the material, Imin = the minimal moment of inertia of the cross section, and L = actual length of the column between its two end supports.

Since at this stress the slope of the material's stress-strain curve, Et (called the tangent modulus), is smaller than that below the proportional limit, the critical load at inelastic buckling is reduced.

Taking into account the fact, that possible structural loads may increase over time as well (and also the threat of progressive failure), massive columns have an advantage compared to non-massive ones.

When seated on a concrete foundation, a steel column must have a base plate to spread the load over a larger area, and thereby reduce the bearing pressure.

It is often referred to as the masculine order because it is represented in the bottom level of the Colosseum and the Parthenon, and was therefore considered to be able to hold more weight.

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 Tuscan order, also known as Roman Doric, is also a simple design, the base and capital both being series of cylindrical disks of alternating diameter.

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.

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.

A Solomonic column, sometimes called "barley sugar", begins on a base and ends in a capital, which may be of any order, but the shaft twists in a tight spiral, producing a dramatic, serpentine effect of movement.

A famous marble set, probably 2nd century, was brought to Old St. Peter's Basilica by Constantine I, and placed round the saint's shrine, and was thus familiar throughout the Middle Ages, by which time they were thought to have been removed from the Temple of Jerusalem.

[6] The style was used in bronze by Bernini for his spectacular St. Peter's baldachin, actually a ciborium (which displaced Constantine's columns), and thereafter became very popular with Baroque and Rococo church architects, above all in Latin America, where they were very often used, especially on a small scale, as they are easy to produce in wood by turning on a lathe (hence also the style's popularity for spindles on furniture and stairs).

The Greek term karyatides literally means "maidens of Karyai", an ancient town of Peloponnese.