Question

A drop hammer is used to drive a wooden pile. The hammer weight is 25 kN and its free falling height is 0.8 m. The penetration in the last blow is 12 mm. What is the nearest approximation to the load carrying capacity of the pile according to the Engineering News Formula?

• A. 125 kN
• B. 110 kN
• C. 3000 kN
• D. 90 kN

Answer 1

The correct option is D 90 kN

(d) As per Engineering News Formula

$Q_{allowable}=\frac{W.h}{FOS(S+C)}$

Where, C = 2.5 cm for drop hammer

weight, W = 25 kW
h = 0.8 m = 80 cm
S = 12 mm = 1.2 cm

FOS = 6

$\therefore Q_{allowable}=\frac{25\times 80}{6\times (1.2+2.5)}$

= 90.090 = 90 kN