Question

A group of 24 piles each of diameter 300 mm and 8 m long are arranged in 4 rows at a spacing of 1.0 m c/c. The capacity of each pile is 300kN. The group capacity of the piles is (in kN).

• A. 3100
• B. 4100
• C. 5100
• D. 6100

Answer 1

The correct option is C 5100


${\eta }_g=1-\frac{\theta }{90}\left[\frac{m(n-1)+n(m-1)}{mn}\right]$

$\theta =ta{n}^{-1}\left(\frac{d}{s}\right)$

$=ta{n}^{-1}\left(\frac{300}{1000}\right)$

$\theta ={16.7}^o$

${\eta }_g=1-\frac{16.7}{90}\left(\frac{4(6-1)+6(4-1)}{4\times 6}\right)$

${\eta }_g=0.7062\underset{–}{\sim }0.71$

$Groupcapacity,Q_g={\eta }_g.n.Q_p$

= 0.71 x 24 x 300 = 5112 kN