A strip footing on a saturated clay possess a bearing capacity of 200 kN/m². What will be the bearing capacity of a circular footing if the diameter is equal to the width?
- A> 200 kN/m²Correct
- B= 200 kN/m²
- C< 200 kN/m²
- DNone of the above
Solution
Concept
Effect of shape on bearing capacity
Formula
Strip: 5.7c (Terzaghi); circle: 6.2c
Step-by-step solution
1. In clay (φ = 0) the shape factor is larger for a circle than for a strip. 2. qu(circle) = 1.3 c Nc ≈ 6.2c vs 5.7c for strip. 3. Hence the circular footing has a higher capacity than 200 kN/m².
Explanation
Shape factors for circular and square footings exceed 1.
Shortcut
Circle/square > strip.
Correct answer: A) > 200 kN/m²