Correct Answer - Option 4 : 6.0
Explanation
News Record formula is used to determine the ultimate load carrying capacity (Qup) of a pile embedded in sand. It is given by:
\({Q_{ap}} = {\rm{\;}}\frac{{{\rm{Wh}}}}{{{\rm{FOS}}\left( {{\rm{S}} + {\rm{C}}} \right)}}\) {For Drop hammer and Single acting steam hammer}
\({Q_{ap}} = {\rm{\;}}\frac{{\left( {{\rm{W}} + {\rm{ap}}} \right){\rm{\;h}}}}{{{\rm{FOS}}\left( {{\rm{S}} + {\rm{C}}} \right)}}\) {For Double acting steam hammer}
Where,
W = Weight if hammer in KN
FOS is Factor of safety which is generally taken ‘6’ for all type of hammers.
H = Height of fall in cm.
S = penetration of pile per blow in cm.
C = Constant for accounting elastic compression of pile and pile cap.
A = area of piston in m2 and p is steam pressure in kN/m2.
The values of S, C and FOS for different type of hammers are given below in tabulated form:
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Single acting Hammer
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Double acting Hammer
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Drop Hammer
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S = Average value for last 25 blows
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S = Average value for last 25 blows
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S = Average value for last 5 blows
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C = 0.25 cm
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No defined value but generally taken C = 0.25 cm.
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C = 2.5 cm
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FOS = 6
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FOS = 6
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FOS = 6
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