If a 3 × 3 pile group has piles of diameter 0.5 m with c/c spacing of 0.75 m, then the dimension of the pile group is
- A2 m × 2 mCorrect
- B3 m × 3 m
- C2.25 m × 2.25 m
- Dnone of these
Solution
Concept
Size of a pile group
Formula
Width = (n − 1) s + d
Step-by-step solution
1. Width = 2 × 0.75 + 0.5 = 2.0 m. 2. Size = 2 m × 2 m.
Explanation
Overall size equals centre-to-centre spacing times (n − 1) plus one pile diameter.
Why the other options are wrong
3 × 3 m would be 3 spacings; 2.25 m is 3 × 0.75.
Shortcut
(n−1)s + d.
Common mistake
Using n × s.
Correct answer: A) 2 m × 2 m