Long column & short column are the two types of columns used in the construction.
The column is basically defined as the vertical member of a structure and it will be subjected to vertical compressive loads.
The line of action of the compressed load will pass through the axis of the columns or sometimes parallel to the axis of the columns.
In simple, a member of a structure will be termed as a column if it is perpendicular and its two ends are strictly fixed and subject to axial vertical compressive load.
Types of columns:
In the design phase of columns, we must determine the group of the columns which are basically divided into two groups, based on the length and lateral dimensions of the columns.
A long columns is basically defined as a columns by which the ratio of the efficient size of the column to the least lateral dimension of the column is greater than 12.
Important characteristics in long columns:
- Long columns will fail due to buckling or bending.
- For longer columns, Euler’s theory will apply.
- The lateral dimension will be significantly smaller than the length of the columns.
- The ratio of slenderness will be greater than 45.
- While the ratio of the effective length of the columns to the lowest lateral dimension of the columns will be greater than 12.
- The load-carrying capacity will decrease with an increase in column length.
Short columns are basically defined as columns by which the ratio of the efficient length of the columns to the bottom lateral dimension of the columns is less than 12.
Important characteristics in long column:
- Small columns will only fail due to crushing or direct compression.
- In these types of columns, Rankine’s principle will apply.
- The lateral dimensions will be larger than the length of the columns.
- The slenderness ratio will be less than 45.
- While the ratio of the effective length of the columns to the lowest lateral dimension of the columns will be less than 12.
- For short columns, load-carrying capacity will be increased with a decrease in column length.
Difference between Short Columns and Long Columns:
|Short Columns||Long Columns|
|If the ratio of efficient length to its least lateral dimension is lower than or equal to 12, it is called a short columns.||If the ratio of the efficient length of the columns to its least lateral dimension is larger than 12, it’s called a long columns.|
|The effective length of the least radius of the gyration ratio is less than or equal to 40.||The effective length of the least radius of the gyration ratio is greater than 40.|
|Bucking tendency is very low.||Long and cylinder columns buckle easily.|
|The tendency to crush is very high.||It has a very low crushing tendency.|
|The load-carrying capacity is higher than the longer columns of the same cross-sectional area.||A long column has a lower load-carrying capacity than a shorter columns of the same cross-sectional area.|
|The failure of small columns is due to their buckling.||All long columns fail due to their buckling.|
|It has a higher radius of gyration.||It has a lower radius of coupling.|
|Due to its lower height, its load carrying capacity is higher.||Its load carrying capacity is low due to its high altitude.|
|They are subject to compressive stresses.||They are subject to buckling stresses.|
|Its slenderness ratio is less than 45.||Its slenderness ratio is over 45.|
|Smaller columns have a larger lateral dimension than its height.||Long columns have a smaller lateral dimension than its height.|
|Shorter columns are stronger than a long columns and it is much better.||A longer columns is weaker than a shorter columns, generally is not preferred.|
Also read: Difference between Beam and Column