Types of Columns in Construction and How They Behave

Columns are the vertical members that collect load from beams and slabs and carry it down to the foundations. They look simple, but there are many types of columns, and each behaves differently depending on its material, its shape, how it is loaded and how slender it is. Knowing these distinctions helps students make sense of structural drawings and helps homeowners understand why some columns can never be touched in a renovation.

This article classifies columns in the ways engineers actually think about them, explains how each type behaves, gives a short worked illustration, and lists the mistakes most often made. It covers structural columns; decorative architectural orders such as Doric or Ionic are a separate subject.

What a column does

The intuition is a table leg. It takes load from above and pushes it straight down. Its main job is compression. In real buildings, however, columns are rarely loaded perfectly centrally. Beams frame in from different sides, floors carry uneven loads, and wind or ground movement pushes the frame sideways. So most columns resist compression combined with some bending.

The distinction between columns and the horizontal members that feed them is covered in our article on beam vs column. A column’s loss usually affects every floor above it, which is why columns are treated as the most critical members in a frame.

Types of columns by material

Reinforced concrete columns. The dominant type in Singapore residential and commercial buildings. Concrete carries most of the compression; longitudinal steel bars add capacity and resist bending, and links or ties hold the bars in place and confine the concrete. Our article on RC column design explains how they are sized.
Steel columns. Usually rolled H or I sections, or hollow square, rectangular or circular sections. Steel is strong for its weight, enabling slender columns, but needs fire and corrosion protection. See our comparison of steel vs concrete structures.
Composite columns. Steel and concrete working together, either a steel section encased in concrete or a steel tube filled with concrete. They combine high capacity with relatively small size and good fire resistance.
Timber columns. Solid sawn or engineered timber such as glulam. Common in low-rise and mass-timber buildings, and in traditional construction.
Masonry columns. Brick or block piers, used for lighter loads in low-rise buildings and boundary structures.

Types of columns by shape

Square and rectangular. The most common in concrete because formwork is simple. Rectangular columns are stronger in bending about their longer dimension.
Circular. Efficient in confinement and equal in all directions, often used where columns are exposed in open spaces, car parks or facades.
L-shaped and T-shaped. Used at corners or wall junctions so the column can hide within walls.
Blade or wall-like columns. Long, thin rectangular sections that fit inside partitions. When the length is many times the thickness, they behave more like walls and are designed accordingly.
Hollow sections. Common in steel, giving good stiffness in every direction for little weight.

Types of columns by loading

Axially loaded columns. The load acts through the centroid, producing pure compression. This is an idealisation; real columns are designed for at least a minimum eccentricity to account for imperfections.
Uniaxially eccentric columns. The load is offset in one direction, adding bending about one axis. Typical of edge columns where beams frame in from one side.
Biaxially eccentric columns. Bending about both axes, typical of corner columns. These are the most demanding to design.

The more bending a column carries, the more reinforcement or the larger the section it needs for the same axial load. That is why corner and edge columns often differ from internal columns in the same building, even where the axial load is lower.

Types of columns by slenderness

Slenderness compares a column’s effective length to its cross-sectional dimensions, and it decides how the column fails.

Short columns fail by crushing of the material. Most concrete columns in ordinary buildings are short.
Slender (long) columns are vulnerable to buckling: sideways instability at loads below their crushing strength. In concrete design, slender columns are checked for additional moments caused by their sideways deflection.

Codes set criteria for when a column must be treated as slender, based on effective length, section size and restraint. The sibling article on slenderness ratio explains the measure.

A simple illustration

Consider two steel columns with the same cross-section and the same pinned ends, one 3 m and one 6 m long. Using the Euler relation P_cr = π²EI / (KL)², doubling the length reduces the ideal buckling load to one quarter. The short column might be governed by yielding of the steel, while the long one could be governed by buckling well before the steel yields. Same section, same material, different type of behaviour.

Types of columns by reinforcement and bracing

Tied and spiral columns

Reinforced concrete columns are also distinguished by how their longitudinal bars are restrained. Tied columns use individual closed links at intervals. Spiral columns use a continuous helix of bar around the main steel, usually in circular columns. Spirals confine the concrete core more effectively, giving greater ductility, which is valued in seismic regions.

Braced and unbraced columns

A braced column sits in a frame where lateral loads are carried by walls, cores or bracing, so the column’s ends do not sway significantly. An unbraced column is part of a frame that resists lateral load by bending of the columns themselves. Unbraced columns have longer effective lengths and carry additional moments, so they are generally larger.

Common mistakes

Treating a blade column as a wall that can be cut. In renovation, a long thin concrete element inside a partition may be a structural column. Hacking or coring it can remove essential capacity.
Assuming all columns in a building are the same. Edge, corner and transfer-level columns are often reinforced differently from internal ones.
Ignoring bending. Designing for axial load alone underestimates demand on edge and corner columns.
Removing bracing. Taking out a slab, wall or beam that restrains a column increases its effective length.
Confusing architectural and structural columns. A decorative cladding column may hide a small steel post, or nothing structural at all; only drawings or investigation can tell.

Frequently asked questions

What are the main types of columns in construction?

Columns are commonly classified by material (reinforced concrete, steel, composite, timber, masonry), by shape (square, rectangular, circular, L or T, blade), by loading (axial, uniaxial or biaxial bending), by slenderness (short or slender) and, for concrete, by reinforcement (tied or spiral).

What is the difference between a short and a slender column?

A short column fails mainly by crushing or yielding of its material. A slender column is long relative to its cross-section and can fail by buckling sideways at a lower load. Slender columns are designed for the extra moments that this sideways deflection produces.

Which type of column is most common in Singapore?

Reinforced concrete columns are the most common in Singapore housing and commercial buildings, typically rectangular or square, with circular columns used where they are exposed. Steel and composite columns are used in many larger commercial and industrial structures.

Why are corner columns designed differently?

Corner columns receive beams from two directions on one side only, so the load is eccentric about both axes. That biaxial bending, combined with compression, makes them more demanding to design than internal columns, which tend to be loaded more symmetrically.

Can I remove or reduce a column during renovation?

Not without a structural engineer’s assessment and, where applicable, the necessary approvals. A column carries load from every level above, and removing or cutting it requires an alternative load path, often a new beam and strengthened supports, designed and endorsed by a qualified engineer.

Unsure whether an element in your home is a structural column? Talk to our consultancy or get in touch before any hacking starts.