1. What is Critical Load on Column?

Definition: Critical Load On Column is the greatest load that will not cause lateral deflection (buckling).

Purpose: It helps engineers determine the maximum safe load a column can bear before buckling occurs.

2. How Does the Calculator Work?

The calculator uses Johnson's Parabolic Formula:

Where:

• \( P \) — Critical Load (Newtons)
• \( \sigma_c \) — Compressive yield stress (Pascal)
• \( r \) — Johnson's formula constant
• \( \lambda \) — Slenderness ratio
• \( A_{sectional} \) — Column cross sectional area (m²)

Explanation: The formula accounts for material properties and column geometry to predict buckling load.

3. Importance of Critical Load Calculation

Details: Accurate calculation prevents structural failures, ensures safety, and optimizes material usage in construction.

4. Using the Calculator

Tips: Enter compressive stress, Johnson's constant (±5%), slenderness ratio (±5%), and cross-sectional area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is slenderness ratio?
A: The ratio of column length to its least radius of gyration, indicating its susceptibility to buckling.

Q2: Why ±5% for some inputs?
A: These values often have manufacturing tolerances or material variations.

Q3: What's a typical Johnson's constant?
A: It varies by material (e.g., 6 for some steels) and must be determined experimentally.

Q4: When is Johnson's formula applicable?
A: For intermediate columns where slenderness ratio is between short and long column limits.

Q5: How to measure cross-sectional area?
A: For simple shapes use geometry formulas; for complex shapes use CAD software or direct measurement.

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