lateral load versus vertical load 1

[efrenfranco]

Good day,

I just want to ask for the lateral load capacity.

I want a clarification for lateral load capacity, am i correct that if the diameter of the pile is increasing the lateral load is decreasing for the same depth?

 

[Teguci]

The question is not clear to me but I can say the following:
1. Lateral Load capacity of the pile (based on its material) is a function of its section modulus (S) and allowable stress. For an increase of diameter, the section modulus increases by the square. Therefore the lateral load capacity of the pile increases with increased diameter (all other things being equal).

2. The lateral soil resistance is typically based on the area of pile pushing on the soil. So, for a bigger diameter, a bigger area of pile is pushing on the soil and, consequently, a higher lateral load is resisted by the soil by larger diameters.

3. The only thing I can think of that might cause a reduced lateral load at given depth would be a function of the pile stiffness. A stiffer pile (compared to a smaller diameter pile) will deflect less at a given elevation and therefore have a smaller lateral load (relatively). This is a function of a long pile being able to redistribute more lateral loads to a deeper elevation. L-pile should give you an acceptable force resisting profile.

 

[efrenfranco]

sir thanks for your rply,

actually sir this my situation.

From Brinch method i used the formula of Pxu = Cu*Kc
where Cu = Unconfined compressive strength
Kc can obtained to the graph that brinch provided (Kc vs. L/D)

Is this applicable to my design for lateral load if i put the pile foundation 21m from the existing ground surface but the basement is at 15m depth from EGS. so my pile length is 6 meter.

my data: UCS of Mudstone 13.1 kg/cm2
angle of internal friction I used is 25 degree

 

[Teguci]

Is your pile considered rigid or flexible?

 

[csd72]

efrenfranco,

No-one is going to do the design for you.

Do you have a specific question?

 

[handex]

The only time I have seen the lateral capacity be smaller for larger diameter piles is when using Broms method. This is because the top 1.5D of soil is neglected in the analysis, so for certain cases it gives a smaller capacity for the larger diameter pile. In these cases I usually just use the depth relating to the smaller diameter pile because it doesnt make any logical sense