Need suggestions for possible friction piles 1

[mahlegreco]

Hello, I have a job in Kearny, NJ with deep loose sands and silts. Traditional wood timber timber don't provide enough capacity for this heavily loaded building of over 1000 PSF. Does anyone have any suggestions for other friction types of piles?

 

[dik]

Franki piles

 

[Panars]

Do you mean the timber piles do not provide enough geotechnical capacity or not enough structural capacity? If the structural capacity of the timber piles is the problem, then driven, closed end steel pipe piles would be a possible solution.

 

[mahlegreco]

Hi, The timber piles do not provide enough geotechnical capacity.End bearing piles would go over 150feet. I was looking for a solution for shallow piles possible 60 feet. The n-values are in the 7/blows range at approx. 60'.

 

[SlideRuleEra]

Both typical prestressed / precast concrete piling and even steel H piling work well as friction piling in many soils.
I don't have any information posted on my website on concrete piling, but see Section 4 of "Bethlehem Steel H Piles" on this page

http://www.slideruleera.net/Steel-Piling.html

http://www.SlideRuleEra.net

 

[GBTDS]

If you are willing to go a little "out of the box", there is a technology that was just brought into the US from Russia which uses EHDE (electro-hydrodynamic effect) which uses an electrode lowered into the concrete to create an insitu wave to compress the surrounding soil in an approximately 2m radius. This actually presses the concrete into the surrounding soil as well to create a mix. The end result is a bulb created at the tip of the pile founded in an extremely dense surrounding soil.
The electrode can also be lifted to create multiple "bulbs" to give more skin friction further increasing its capacity.
Think of it as a Franki Pile on steroids!
I can forward you the name of the company that has imported this technology for further reference if you are interested.
This is an extremely cost effective solution.

 

[mahlegreco]

Thanks to everyone for their great information and suggestions.

GBIDS - I would definitely be interested in the name of the company for more information.

 

[GBTDS]

The person to speak to is Jerry - he is the principle at Geotechnical Design Services Inc. near Salt Lake City, UT
I don't have the phone number handy but you can most likely find it on the web or by calling directory assistance.
Having seen the technology first hand it is really exciting - it is actually written into the Russian Building Code and has even been used for underpinning of historic landmarks in St. Petersburg.
Jerry will have more info I am sure.

 

[TDAA]

You may also want to look at Geopiers (rammed aggregate piers) as a ground improvement to allow for construction of a shallow foundation system. Their particular process is proprietary, so it may not be allowed (without bidding) depending on the money source of the project.

Based on their preliminary chart, you should be able to get capacities in the range of 7000 psf with granular soils at 7BPF.

You may also want to price out removal and recompaction to a depth below footings. I have found that to be economical in some instances, where space permits.

 

[dik]

I also think the patent for Franki piles has expired and there is no licensing for the method in place. This may reduce costs, and they have a fairly large load capacity.

Dik

 

[HCN]

Auger Cast Piles

 

[BigH]

Franki piles have a long history in the New Jersey area - most of the Atlantic City Casinos are on Franki (or expanded base (generic name)) piles where up to 300 tons (of which I am aware) have been used (and tested) in the past. You could also consider monotube which are tapered piles. Tapered piles have the advantage of both friction and a bit of bearing due to the taper - see Nordlund's computations (as, for example, given in Tomlinson's Fdn Dsgn book). One item of caution - there is always a possibility of a thin clayey seam in the sands which may trigger a "bad" result if close to the tip of the pile - I of aware of this happening at least once.

 

[DRC1]

Try Monotube piles. They can generate considerably more capacity than timber piles and can be driven by conventional equipment. They were recently used up at one of NY airport expansions. They can provide engineering support.

 

[GTeng]

Several things come to mind as I read the original post and replies.
The site includes loose sandy and silty soil, yet several of the methods suggested may cause vibrations that could result in settlement damage to nearby utilities or structures.
Steel H-piles don't seem to be a good idea because as low-displacement piles, sometimes they "run" during driving. It seems obvious that if there are no vibration issues, using a displacement pile to maximize the end bearing resistance would be appropriate.
I have to get on the soapbox for the final comment. This site is an excellent place to get a variety of opinions on geotechnical issues, but an open-ended post like this always makes me wonder if these discussions pages are really a good idea after all. Presumably, Mahlegreco is working with a geotechnical engineer with the appropriate experience to direct this work, and is simply looking for more information to support the process. However, without some statement confirming this to be true, I have to wonder if it is even appropriate to even respond. Geotechnical engineering can't and shouldn't be done anonymously without knowing all of the facts. Site conditions like those described really require someone with the right local experience, not just for technical reasons, but also to understand local contractor issues etc.

 

[Panars]

GTeng- You are right that it is not appropriate to perform geotechnical engineering without knowledge of site conditions and local geology. However, I do not think that is what we are doing in these forums. We are discussing ideas and giving guidance to other engineers for further research. If you or anyone is not comfortable replying to open-ended questions, then do not reply. There are many, many questions to which I choose not to reply for that very reason. However, I think these forums are invaluable for getting opinions on a wide range of topics.