Practice Question: Pile Penetration per Blow Employing Single-Acting Air Hammer

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Solution

Pile penetration per blow (set) can be determined by using Modified Engineering news Formula:

\[P_{allow}=\frac{2E_n}{S+k}\]
Where:
\(P{allow} = Allowable\ pile\ load\ (lb)\)
\(E_n = driving\ energy\ (ft-lb) = weight\ of\ hammer × drop\ height\)
\(S = pile\ penetration\ per\ blow\ (set)\ (inch)\)
\(k = constant\ based\ on\ hammer\ type\ (0.1\ for\ single-acting\ air\ hammer)\)

 

\[S=\frac{2E_n}{P_{allow} -k}\]\[S=\frac{2(40,625)}{20,000}-0.1\]\[S=3.97\ in≈4\ in\]

 

 

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