Seismic Stiffness for Pile Design 1

[MarkDK]

Dear all,

I am looking for a correlation to determine seismic stiffness based on SPT or Shear Vane measurements. Any tips?

 

[Mccoy]

MarkDK,
if by seismic stiffness you mean shear-wave velocity (Vs), then by far the most popular correlation is Otha & Gotho
(1978):

Vs = 68 * (NSPT)^0,17 * z^0,2 x fA x fG

where:
z= depth in meters

fA= age factor
fG= grain size factor

fG
clay 1.00
sand, fine 1.09
sand, medium 1.07
sand, coarse 1.14
sand, gravelly 1.15
gravel 1.45

fA
Holocene 1.0
Pleistocene 1.3

More correlations are used, but I don't have'em at hand, and don't know if they have a more successful experimental record.

As to Vane-test Cu, there is something but I'm not sure where, I'll be back to you if I'm able to retrieve some info