Pile Foundation for a Tank

[zestructural]

Hi All,

This is my first time to design a pile foundation for a tank. I need tips from the experience engineers. Thank you in advance. I have a 40' dia. tank and use 44' dia. pile cap. Here are the steps I followed from a foundation textbook:
1. Find P (Total WT of tank and fluid)
2. Allowable bearing capacity per pile/F.S
3. No. of piles = P/ cap. per pile.

Do I need to consider the pile layout factor since the spacing is not the same? Any other factors I need to add to increase/decrease the pile capacity?

 

[jdonville]

zestructural,

Do a search on tank foundations on this site. Plenty of posts in the geotechnical and structural forums.

SlideRuleEra has a tank foundation paper on his website

http://www.slideruleera.net

that you may wish to use for reference.

Finally, discuss your design and analysis approach with a senior structural or geotechnical engineer within your firm, within a subconsultant's firm or local professional society chapter, if possible. Consider buying a tank foundation design text and a copy of the API tank guidance.

Local conditions and practice for tank foundations may vary from place to place and may also depend on the industry your client is in.

Jeff

 

[zestructural]

Thanks, Jeff.

 

[civilperson]

Apply wind or seismic lateral loads to increase the piles loads on one side of the cap.

 

[JedClampett]

I just had the occasion to work on a pile supported tank. There are a circular pattern of piles around the tank perimeter that support the tank wall, the tributary roof weight and live load and a portion of the liquid load. In the tank interior the piles are spaced based on their capacity divided by the floor weight and maximum liquid level weight. Ours were spaced at about 6'-6".
Basically, it's pretty much weight of tank plus contents divided by the pile capacity.

 

[AllStructure]

Try to keep a 2.5*d_pile spacing. whatch for tension on piles due to overturning effect.