Acceptance Criteria for Timber Piles

[tclat]

Hi,

I am working on a small timber jetty supported on 10" dia timber piles. The maximum working load on a single pile is 2 kips. We plan on load testing the piles and I am looking for some advice on acceptance criteria for lightly loaded piles such as in this case.

Thanks

 

[BigH]

2 kips on a 10 in dia timber pile? Seems a real overkill with respect to vertical load. Timber piles can be easily good for 20 to 30 tons even driven 5 ft or so into a compact sand layer. You can use the Gates formula.

Being for a jetty, your criteria might better be embedment required to ensure lateral stability of the structure. What about that?

 

[tclat]

The load is small but the piles are being driven in a swamp so I was concerned about settlement.

Any comment?

 

[BigH]

What is the soil stratigraphy - what is under the paludal deposit? Are you anticipating adding fill that could cause downdrag? How deep do you expect to drive the piles so that you have some embedment into competent soil? Have you done any geotechnical computation as to the capacity of the pile driven to the depths that you envisage? - again, 2 kips is so small - that even a foot or so into a sand layer will be okay for load.

but, - as I indicated, lateral stability of the pier will be important and this might not be achieved if you are only driving into and not through the swamp deposit (paludal). Not sure that you will need to load test a pile for that small load - which might be less than the pile weight.

The other aspect that you need to consider is weathering of the pile - will these be creosoted or . . .? Wet/dry cycles on timber piles can be detrimental.