pile stiffness 1

[geotechLTIS]

Hello everyone,
I am newly joined.
can anyone support me for the simplified estimation of vertical and horizontal pile stiffness?
thanks

 

[ukbridge]

Do you mean the structural stiffness of the piles, or the stiffness of the soil strata? It also depends on how close the piles are spaced.

In my company at least we divide the strata into appropriate layers, with representative soil parameters. We then use a program like WALLAP or FREW to determine rotations and displacements, which we can then use to calculate spring stiffnesses.

 

[geotechLTIS]

thank you UKbridge
I mean the stiffness of soil strata?

 

[Mccoy]

geotech, there are different levels of details in determining pile displacements thru soil reaction, the simplest one, that I know, is the representation of a single spring for every degree of freedom.
That is, you represent pile displacement at the pile cap, one vertical spring, one horizontal, one torsional one rocking spring and maybe others depending on simmetry.
Gazetas 1991, in Feng: Foundation Engineering Handbook, is my favourite reference, a section is dedicated to the spring stiffnes of pile(cap)s, also called impedence when are related to dynamic conditions.
as UKbridge hints, stiffness of single pile must reduced when it belongs to a pile group.

UKbridge, as far as I know Wallap is used for soldier pile walls, do not know if it deals with isolated or foundation piles...

 

[geotechLTIS]

Mccoy, thanks.
its a good input.