Design of Steel cased mini piles with reinforced concrete infill

[engstructural]

Reinforced Concrete filled Steel mini Piles

Hi all,

Can anyone advise me of where I can find info on the design of reinforced concrete filled steel mini piles (preferably UK). The piles would be approx. 220mm dia with a central length of rebar.

As I see it I need to consider design for load regarding the end bearing and skin friction but I am also interested in the limitation of the pile itself. As I see it the pile is acting as an axially loaded column (probably not load eccentricity) and the column is restrained by the soil. The axial capacity would be the combined capacity of the steel casing and the RC core. I am not sure how to take account of the restraint by the soil, how is this done and justified?

 

[ChaChaMan]

....from what I remember, in driven (hammered) piles, buckling is discounted as the soil is assumed to be bracing laterally the pile. Materials are heavily factored because of dubious quality.

 

[enko]

The most exact solution would be modeling of the pile-soil interaction.That means defining the spring stiffness in horizontal direction through the depth of pile and vertical direction in function of soil properties.
I use Bowles for these parametres.
After modeling you can make the concrete design easy.

Anyway as preeliminary design you can make a compression only concrete design if the pile bottom reaches a rigid strata.