👉Effective Length of a Column

💫Effective length (Le) of a column is the length between points of zero bending moment (contraflexure). It depends on the end support conditions, not only on the actual height.

Formula:
Le = K × L

Where:
L = actual unsupported length of column
K = effective length factor (depends on end conditions)

⭐️Effective Length Factors (K)

1. Both ends hinged (pinned–pinned)
K = 1.0
Le = L

2. One end fixed, other end free (cantilever)
K = 2.0
Le = 2L

3. One end fixed, other end hinged
K = 0.7
Le = 0.7L

4. Both ends fixed
K = 0.5
Le = 0.5L

🚧Importance of Effective Length

• Used to calculate slenderness ratio
• Helps predict buckling failure
• Important in RCC and steel column design

🏷Example

Actual column height = 3 m

Both ends hinged:
Le = 1.0 × 3 = 3 m

Both ends fixed:
Le = 0.5 × 3 = 1.5 m

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