Architectural Supports & Columns

Function

• Columns and supports are required to keep a building standing, but it is not only downward forces that must be sustained. Structures must also bear lateral forces from wind, water and complex geometries, such as arches and domes. Columns are not strong in resisting lateral forces, so these columns are used in combination with shear walls, diagonal braces and buttresses.

  Defined downward and lateral loads can be countered with bents, or diagonal columns, as well as buttresses. However, forces that change or distributed out of a structural plane may require shear walls or mass such as earth or heavy masonry to resist the complicated forces.

History

• Walls are the earliest form of human structure, and over thousands of years, the walls evolved to create linear columns. A language of trabeation, or post and beam construction, developed into a very specific and detailed system of building with the Greeks. The classical Doric, Ionic, Corinthian and Composite orders are the result of this development.

  Before the Greeks, the Babylonians and Persians developed arches and vaulting to transfer loads to walls and piers, and well after the Greeks, the peoples of the Near East developed similar structures, such as the squinch, to carry the loads of the three-dimensional dome.

  The advent of steel brought thinner columns, as well as the use of diagonal bracing elements, such as bents and braces. Today, complex structural assemblies are used to counter complex loads from various sources, including winds, earthquakes and other structures bearing on a building.

Column Structure Types

• The column must transfer a structure's loads to the ground, but the column must also resist torque, or moment. A moment connection on a column prevents a column from falling or folding with lateral forces. However, a column typically uses a pin connection which is simply a connection that bears downward force, but acts as a hinge when lateral forces are applied. Diagonal bracing will help a column with pin connections resist failure.

  In addition, a column can fail from bending, where the column bows to a downward force. A column failure from bending is the result of inadequate support or bracing to the length of the column, and it can be countered using lateral braces at the midpoint of the column or thickening the column.

Benefits

• The use of columns and other architectural supports has opened up structures' floor plans, allowing the buildings to be used for multiple and varying uses. Furthermore, the use of thin columns opens a building's interior to light and greater air circulation. Although walls can create an effective and dramatic structure, the economical column can provide many more architectural opportunities for a structure.

Future

• As engineers and architects experiment with structure, buildings will begin using complicated non-linear structural systems that could deny the need for columns and other interior support. The shell structure, such as a dome, are a good precedent for where the discipline of architectural support may be heading.