[amp_mcq option1=”Q = Wh/6 (S + 2.5)” option2=”Q = Wh/2.5 (S + 6)” option3=”Q = (W Ã 6)/h (S + 2.5)” option4=”Q = (W Ã 2.5)/6 (S + h)” correct=”option1″]
The correct answer is: A. Q = Wh/6 (S + 2.5)
The Engineering News formula for obtaining safe bearing capacity of pile for drop hammer is:
Q = Wh/6 (S + 2.5)
where:
- Q = safe bearing capacity of pile (kN)
- W = weight of hammer (kN)
- h = height of drop (m)
- S = penetration of pile per blow (mm)
The formula is based on the assumption that the pile is driven into a homogeneous soil with a constant bearing capacity. The formula is conservative and should be used with caution in soils with variable bearing capacity.
Option B is incorrect because it uses the wrong value for the constant 2.5. Option C is incorrect because it uses the wrong units for the constant 6. Option D is incorrect because it uses the wrong order of the terms in the formula.