how to design the piles with base shear & with loose soil ??

[Dhavalcooldued]

HI,
I am designing the Pile ( 40' long) foundation for the SILO & the soil is very loose soil but my base shear is kinna high .M not sure how to resist the base shear Using piles as the top 18' of soil is really loose soil & cant take any shear.??

 

[edwin17th17]

hmmm.. shouldnt the piles have lateral capacity table from geotech.. and you just need to compare it to actual horizontal loads..

 

[Dhavalcooldued]

well i do have geothech report for lateral capcity bbut its not even enar to the capacity i am looking for...so i am asking is there any other way to brace the piles for base shear.

 

[JLNJ]

LPile, clumsy and painfully un-user-friendly as it is, will give you the analysis you are looking for. If the top 18' is worthless then you are looking at a deep embedment and a big pile.

Battered piles may be a possibility. Talk to the geotech.

 

[ron9876]

You will probably need to batter the piles in addition to the lateral capacity of the piles. What type of piles are you using.

 

[BigH]

On thing you might consider is to make the pile cap a bit thicker (and deeper). Then replace the loose soil in the passive zone with a well compacted crushed stone well graded sand and gravel - ensuring that the passive slip line as the cap "pushes" into the engineered zone is always within the zone. You then might get sufficient lateral capacity against the shear by the pile being "reinforced" by the effects of the pile cap.

 

[escrowe]

Consider tying the pile caps with grade beams
for additional lateral capacity.
If this technique is not feasible, consider a drilled shaft
or mat foundation, as opposed to a forest of smaller piles.

What is the soil type?

 

[asixth]

Tie the piles together using a pile cap if the soil is bad. Design as a floating pile, Brom's method. You won't necessarily need a pile design package, it can be easily programmed into a spreadsheet.

Basically you need passive resistance in the pile to react the base shear. Then you need passive resistance to react the couple cause by the base shear and base shear reaction.

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