Introduction to Columns in Building Structures

Importance of Columns

• Columns are the most critical structural element in buildings.
• A significant number of structural failures are attributed to column failure.

Functionality of Columns

• Plain concrete columns can carry compression forces.
• Adding vertical bars to plain concrete columns greatly enhances their ultimate capacity.

Role of Lateral Reinforcement

• Lateral reinforcement or ties provide support to longitudinal bars, decreasing their tendency to buckle out.
• They prevent concrete from expanding laterally due to Poisson's effect, increasing the concrete's ultimate strain.

Classification of Reinforced Concrete Columns

• Reinforced concrete columns are classified into two types: tied or spiral, based on the lateral confinement type.

Eccentricity in Columns

• In actual practice, axially loaded columns do not exist, and some percentage of eccentricity always occurs.
• Eccentricity can be caused by the reduction of column size from one floor to another or the misalignment of the column.
• A minimum longitudinal reinforcement ratio is required to account for stresses resulting from eccentricity.

Classification of Columns based on Length and Restraint

• Reinforced concrete columns are classified as short or long, depending on the length to width ratio and end restraint conditions.

Learn about the importance of columns in building structures and how adding reinforcement can enhance their capacity. Understand the role of vertical bars, lateral reinforcement, and ties in preventing structural failures.