Determine the load carrying capacity (kN) of a pile foundation using Engineering news Formula. The details are: Wooden pile, Weight of drop hammer = 30 kN, Height of free fall = 1.0 m, Penetration in last blow = 5 mm
- A121.1
- B166.7Correct
- C101.1
- D91.1
Solution
Concept
Engineering News formula gives safe load from hammer weight, drop height and last-blow penetration (with 25 mm constant for drop hammer).
Formula
Qa = W H /(F (S + C))
Step-by-step solution
1. W = 30 kN, H = 1.0 m = 1000 mm, S = 5 mm. 2. For drop hammer, C = 25 mm. 3. Ultimate load Qu = W×H / (S + C) = 30×1000 / (5 + 25) = 1000 kN. 4. Safe load with FS = 6: Qₐ = 1000 / 6 = 166.7 kN.
Common mistake
Mixing units of S and H.
Correct answer: B) 166.7