Pile tip torsional capacity
Pile tip torsional capacity
(OP)
I was reading a paper which stated the pile tip torsional capacity was as follows:
Tt = π.(D/2)2.L.γ.(D/3).tan(δ)
Where:
Tt = Pile tip torsional capacity
π = pi (3.14...)
D = Pile diameter
L = Pile length
γ = Material unit weight (concrete in the example)
δ = Interface friction angle at pile tip
I understand where everything apart from the (D/3) part comes from. Can anyone shed some light on what the (D/3) part relates to/how it is derived?
EDIT: Essentially the above comes down to:
Tt = τ.(D/3)
Where:
τ = shear stress
I'm not sure why shear stress is multiplied by D/3.
Tt = π.(D/2)2.L.γ.(D/3).tan(δ)
Where:
Tt = Pile tip torsional capacity
π = pi (3.14...)
D = Pile diameter
L = Pile length
γ = Material unit weight (concrete in the example)
δ = Interface friction angle at pile tip
I understand where everything apart from the (D/3) part comes from. Can anyone shed some light on what the (D/3) part relates to/how it is derived?
EDIT: Essentially the above comes down to:
Tt = τ.(D/3)
Where:
τ = shear stress
I'm not sure why shear stress is multiplied by D/3.





RE: Pile tip torsional capacity
www.qsystemsengineering.net
RE: Pile tip torsional capacity
I can't actually remember the reference now, I'm afraid.
RE: Pile tip torsional capacity
π.(D/2)2: the pile end area;
π.(D/2)2xL.γ: the contact vertical force between the pile end and the soil
π.(D/2)2xL.γ*tan(δ): the contact shear force between the pile end and the soil
D/3: the force arm.
RE: Pile tip torsional capacity