Pull-out calculation Steel-Pile

[Bartz]

The problem is as follow:

Steel-pile,
2.50m diameter,
15m length,
clay-soil (I don´t have any detail soil parameters at this moment),
slope (h/l)= 4/1

I´m looking for some formulares to determnine the necessary forces to pull-out these pile by an offshore-crane.
It is possible to pull-out this pile by crane?

 

[ishvaaag]

If you align the tension with the pile from a barge for unconfined compressive strengths of the clay in the column at left expect required extraction forces bigger than those at right

1 kgf/cm^2 435 metric tons

3 kgf/cm^2 834 metric tons

5 kgf/cm^2 1473 metric tons

Being in contact with water the lower values seem more likely.

 

[Qshake]

A couple of questions, based on my experience in marine facilities, is this crane permanently mounted or barge mounted? If barge mounted, does the bouancy of the barge limit the capacity of the crane? Based on those two what is the pick capacity of the crane?

Also, do you have a vibratory pile driver handy? If so, use it, it work wonders on extracting pile.

 

[DRC1]

It is dangerous to try to pull sheets in clay from a barge. The cohesion can be easily computed, but the suction will be the driving force. If you exceed your predicted pull out, you may exceed your rated capacity, which wil greatly incease your barge list, which will reduce your crane capacity. This often does not end well. The 1: 4 batter does not help as you can not pull the piles axialy. A vibratory hammer as suggested by Qshake does greatly reduce the required pull, although I can do not know of any way to compute it. But because these are batter piles I would have a good sized crane on a good sized barge as you will have to follow th pile for some distance when you extract it.
Good Luck!

 

[ayfarm]

I do this kind of work for a living. Yes you can pull the pile. The only question is money if you have the time. A vibro will work but there is a cheaper way to do it. To arrive at the cheapest way is to know these info.
When was the pile driven
Soil info
driving info
hammer info
available barges, derricks and floats locally
workmen
tidal info.
The first thing to consider is to pull it using floats/barges and tidal action. For further info, just ask me.