Natural draft cooling tower foundat

[engineeringofcivil]

Natural draft cooling tower foundation is subjected to huge horizontal load mainly due to wind. I need to design the pile foundation for the same .Can I take passive resistance developed in pile cap from back fill soil to counter the huge horizontal force developed mainly from wind. Raker pile is not possible due to specification restriction . It will be of help if I get a response.

 

[SlideRuleEra]

.Can I take passive resistance developed in pile cap from back fill soil to counter the huge horizontal force developed mainly from wind?

Yes, if the backfill is performed correctly. The passive pressure may, or may not, be enough to offset the wind load. Be conservative when calculating the passive pressure... don't just "make the numbers work".

If the cooling tower basin can be partially embedded in the backfill this will add more area for the passive pressure to work against.

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[engineeringofcivil]

Thanks.

However the pile cap is annular.Will there be any other consideration.Finally since wind can blow any direction,reversible, Passive pressure will develope when there will be some displacement in the backfilled soil.Now when wind.will blow in opposite directoon, displaced backfilled soil may not come nack to its original position. In that case will the passive pressure act?

Hope I am able to express my doubt. Your view please.

 

[SlideRuleEra]

engineeringofcivil - I know the tower/basin/pile cap are annular, that is not a problem. If anything it makes calculating wind loading from any direction easier. As I stated earlier, the backfill has to be placed correctly - this will allow maximum passive soil pressure with minimum displacement. Putting the pile cap deeper, by partially embedding the basin, will help also.

Since raked piling are not acceptable, there are not many other options besides using passive soil pressure. Have you investigated how much lateral load the (vertical) piling can resist? I know there will be a very large number of piling. IMHO, the piling / backfill needs to be designed and installed right - best to get a geotechnical engineer working on this project. It is unlikely that just adjusting the pile cap design will do the job.

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[engineeringofcivil]

Thanks for the support, I will take help of Geotechnical expert.