Civil Engineering MCQAE Level Civil Engineering
The Converse-Labarre formula for efficiency of a pile group with n rows x m columns, diameter d, and center-to-center spacing s is:
Foundation EngineeringPile Group EfficiencyMEDIUM
Choose the correct answer
A
Eg = 1 - (theta/90) x [(n-1)m + (m-1)n] / (mn)
B
Eg = 1.0 always
C
Eg = n x m x individual pile capacity
D
Eg = s/d ratio
Correct Answer
A. Eg = 1 - (theta/90) x [(n-1)m + (m-1)n] / (mn)
Why is this the answer?
Converse-Labarre: Eg = 1 - (theta/90) x [(n-1)m + (m-1)n] / (mn), where theta = arctan(d/s) in degrees, m = number of columns, n = number of rows. Typical Eg = 0.6-0.8. Group capacity = Eg x n x m x individual pile capacity (or lesser of group block failure).
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