Ultimate Load Carrying Capacity of Pile Constructed in Sand
Ultimate load Qu = Qp + Qs - W
Where
- Qp = point or base resistance
- Qs = shaft resistance
- W = weight of pile
Step One: Calculate Qp
Qp = Ab (Fb + Po)
Where
- Ab = area of base of the pile
- Fb = net ultimate resistance per unit area
- Po = over boarding pressure at the level of the base
Ab = πr2
Ab = π x 2 = NaNm2
Fb = Nqσv
Where
- Nq = bearing capacity factor (18 for sand)
- σv = vertical stress at the base of the pile
σv = Zγ
Where
- γsat = saturated unit weight
- Z = pile penetration depth or height of pile below ground level
Fb = 18 x x = NaNKpa
Po = σv = x = NaNKpa
Qp = NaN (NaN + NaN) = NaNKN
Step Two: Calculate Qs
Qs = AsFs
Where
- As = surface area of the pile shaft in contact with the soil
- Fs = average ultimate side resistance per unit area
As = 2πrZ
As = 2 x π x x Z = NaNm 2
Fs = Nq/50σv'tanφ = Nq/50(σv/2)tanφ
Fs = 18/50 x NaN/2 x tan = NaN
Qs = NaN x NaN = NaNKN
Step Three: Calculate W
W = γcV
Where
- γ = unit weight of pile
- V = volume of pile
V = πr2
V = π x 2 x = NaNm 3
W = x NaN = NaNKN
Finally, Ultimate Load Carrying Capacity, Qu
Qu = NaN + NaN - NaN
Qu = NaNKN