Double Splicing Timber Piles

[Geoman69]

Is it okay for 55 ft long timber pile have to have two splices? That is, top 15ft treated, middle 20ft also treated, lower 20 ft untreated. Will this reduce the pile capacity?

 

[SlideRuleEra]

Two splices in one timber pile... doubt you will find any authoritative source that addresses that situation. Even one splice should be avoided when possible.

Is this someone's (wild) "scheme" to "save money" by using short available treated and untreated piling? If so, do a cost estimate the cost to furnish / install splices then (try to) drive the pieced-together-pile. Compare this cost with furnishing and driving appropriate full-length piling.

Will it reduce pile capacity? IMHO, if the pile survives being driven (a big "if"), then for point bearing piling, absolutely reduced capactity. This assumes the soils surrounding the pile are "poor" and lack lateral support for the piling... otherwise 55' long piling would not be needed; shorter friction piling would likely be adequate.

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[oldestguy]

What does this support? Sounds like the guy didn't have a supply of longer piles and you maybe got left over-cutoffs. Sounds bad, but for some installations it may be ok.

 

[Geoman69]

The water table was 18 ft deep during site investigation (3 years ago)and the piles have been shipped (20ft treated, and rest untreated). Unfortunately the water table now is 30ft, so the purpose is to use the ordered material, with two spilces, if okay. The piles will support house, upper 20ft fill, underlying 20 ft peat, underlying 15ft of soft silt, underlying dense sand for pile end bearing. I am using timber pile 8-10 inch diameter, allowable pile load 25 kips.

 

[dcornelius]

That doesn't sound like an engineer designed pile. Sounds more like a surplus of 20-30 foot piles that the supplier told you it would work.

 

[SlideRuleEra]

Geoman69 - You don't seem to want to take "no" for an answer. Why don't you try the two-splice "scheme" and see what happens. BTW, I not being sarcastic, the short piles are available, maybe it will work.

Edit: If the piles can be successfully "stood up" (without breaking at a splice), I would not to be nearby when driving is attempted... risk of flying debris.

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[oldestguy]

Sounds like settlement maybe expected as the site settles with lower ground water,among other factors.. What's your negative friction load as the peat compresses? As ground settles and building stays up, have some rat traps on hand for those living under the house.

 

[SlideRuleEra]

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[boo1]

Why use untreated pile for a residential foundation, stop and order the correct treated pile the correct length