# Fundamental concepts of Column

A column is a special case of a compression member that is vertical.

A reinforced concrete column is basically a vertical structural member, which helps to transfer the load from top to bottom in a framed structure. Specifically, columns transfer the compressive load from the top floor to foundations. Normally, we use concrete and reinforcement. reinforcement by means of :

• main longitudinal bars to resist compression and/or bending
• transverse reinforcement (ties) to resist bursting forces.

Check out this post to know more about columns and its types.

### Longitudinal axis

It is basically the axis passing through the centre of gravity of section along the length wise direction of the body.

### Transverse axis (Lateral axis)

It is basically the axis passing through the centre of gravity of section perpendicular to the longitudinal axis. In a member with rectangular cross section, axis parallel to the width (local Y axis) is lateral axis, and axis parallel to the depth is vertical axis (local z-axis). Transverse axis are further characterised into major and minor axis.

### Major axis

The axis about which the moment of inertia is larger is termed as major axis.

### Minor axis

The axis about which the moment of inertia is smaller is termed as minor axis.

In structural engineering basically the terms force and loads is interchangeable. Load is a term, we use frequently in engineering to mean the force exerted on a surface or body. A column by definition is a structural member primarily subject to compressive loads. In general a column is subjected to axial Force, Shear force, Bending moment, torsional moment.

Generally we design the columns so as to resist the axial compression load or sometimes a combination of bi-axial/ uni-axial moment acting on it. It is very important to consider all these loads which is basically due to the frame action under gravity and lateral loads.