The ultimate bearing capacity of a square footing on surface of a saturated clay having unconfined compression strength of 50 kN/m² using Skempton equation is
- A150 kN/m²Correct
- B140 kN/m²
- C130 kN/m²
- D120 kN/m²
Solution
Concept
Skempton bearing capacity
Formula
qnet = 5c (1 + 0.2 B/L)(1 + 0.2 D/B)
Step-by-step solution
1. c = qu/2 = 25 kN/m². 2. Surface footing: D = 0; square: B/L = 1. 3. qu = 5 × 25 × (1 + 0.2) = 150 kN/m².
Explanation
c = qu/2 = 25 kN/m².
Shortcut
Square surface: 6c.
Common mistake
Using Nc = 5.14 or 5.7.
Correct answer: A) 150 kN/m²