Question

A timber pile of length 8m and diameter of 0.2m is driven with a 20 kN drop hammer, falling freely from a height of 1.5m. The total penetration of the Pile in the last 5 blows is 40mm. Use the engineering news record expression. Assume a factor of safety of 6 and empirical factor (allowing reducing in the theoretical set, due to energy losses) of 2.5 cm. The safe load carrying capacity Of the pile (in kN, round off to 2 decimal places) is

• A. 151.515

Answer 1

The correct option is A 151.515
Engineering news record expression
$Q_u=\left(\frac{wh}{s+c}\right)$
$s=Penetrationofpileperhammerblow=\frac{40\text{mm}}{5}=8\text{mm}=0.008\text{m}$

$C=2.5\text{cm}=0.025\text{m}$

so,
$Q_u=\frac{20\times 1.5}{(0.025+0.008)}=909.09\text{kN}$

then safe load carrying capacity

$=\frac{909.09}{6}=151.515\text{kN}$