Timber Piles

[connect2]

Early days.
What would be a general sort of rule of thumb for the allowable load for a timber pile? 20 tons?
Just ballparking some stuff. Yes there's lots more info needed.
Thanks

 

[SlideRuleEra]

IMHO, 20 tons is a good upper limit for a typical timber pile completely embedded in good soils (as in a foundation). Lower for poor soils or if the pile is cantilevered above the soil (as for a waterfront dock).

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[connect2]

should add, endbearing through dredged mixed fill, then clay to refusal in glacial till, length about 50 feet, there's about 4,800 of them carrying a structure built in the early 30's, not much known about them except they were locally provided, minimum dia 12" on drawings, likely red pine, likely treated.

 

[JedClampett]

Why don't you test them?

 

[connect2]

Hi,
thanks for the replies.
SlideRuleEraa; Yes that's my starting ball park number as well.
JedClampett; Load Testing is for sure where we need/will end up. Access for testing and condition assessment though is very difficult and complicated.

It is a waterfront structure, a port, an elevator with a capacity of 155,000 tons of product alone.
so at 20 tons per pile, never mind condition, down drag, etc., etc., the drawings indicate 4,800 piles, 155,000/4,800 = 32 tons per pile product only and that doesn't include the weight structure or any other loads such as berthing.

 

[Ron]

Look at the serviceability of the whole system. What happens if you have a shut-down of this elevator? While wood piles have an excellent service record, I'm not so sure I would want to place such a critical structure on such a large number of wood piles.

I'm sure you've probably considered other foundation systems and I'm sure the owner wants to save money wherever possible, but the initial cost of a more robust deep foundation system would pale in comparison to a failure.

 

[BigH]

There is a Timber Foundation Series of articles that you can find on the internet - I have the original book back in storage - a lot of the articles are for Louisiana . . . I've used more than 20 ton (at 2000#/ton) on timber piles - mainly into compact sand. Can look at Nordland's equation for tapered piles; also, in driving, check with the modifications for Gates Formula (yeah, I know that many don't like driving formulas . . . but . . .)

 

[SlideRuleEra]

BigH - Are these articles on my website the ones you mentioned?

http://www.slideruleera.net/TreatedWood.html

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[BigH]

Sure are SRE . . . I do remember, now, that you had these . . . I had the book (but in deep storage in Canada).