pile design 1

[ctm]

How are the allowable lateral load and the allowable moment on a pile related? This question arises from a pile elevated flate plate design. Since no shear walls are being used below the slab, the piles must handle the lateral and moment producing wind load as well as the gravity produced moment transfer of the slab.

 

[ronster]

Piles would take the transfer lateral load as cantilevered embeded flagpoles. Exerting a lateral passive pressure on the soil.

 

[Gourile]

ctm!
You should first define whether you are working with piles as a group or singlly. The situation is quite complicated as there is a combination of compression, bending and shearing effects on a pile. Allowable loads depend on the length, size and shape of the pile as well as the soil media. For more information see API RP2A (American Petroleum Institute code of practice for design of fixed offshore structures). It contains a separate chapter for design of piles. I'm sure it would be satisfactory as it contains a good bibliography as well.

 

[ctm]

Ronster,
Thanks much for your help. Since I'm working with precast concrete piles and can get a moment capability way beyond what I would need for the slab transfer moment and the lateral flagpole moment, I take it that I'm really limited by the lateral capability of the soil pile interaction. Please confirm and thanks again.
Gourile,
Thanks for your reference. I will follow up.

 

[ronster]

Yes, soil allowable passive pressure should control in your case. Do you have a program or any material available on such a design? If not, I'll try to help you out. Basically you take a point of 0 pressure about 2/3 down the embeded depth of the pile, triangulate your soil pressures against the pile using the maximum allowable for the soil conditions based on the depth of soil. Reiterate as needed to balance your forces.