I agree with this set of recommendations, but they may require some technology or skills that are not widely available. You also need to be careful that tools such as WEAP and PDA are used by suitably qualified practitioners. Like egophysics, it is a relatively easy thing to buy the gear and offer the service, it is quite another to use it to provide meaningful results.

There is also a guideline for matching the hammer's ram weight to the weight of the steel pile by some ratio, for best efficiency of driving and lower risk of pile damage, but I just cannot put my hands on the recommend ratio at the moment, or recall where I saw it (many years ago). It may have been in an old bridge design code.

From: Geotechnical Engineering Email List [mailto:[log in to unmask]] On Behalf Of Kazem Fakharian
Sent: Thursday, May 05, 2011 6:53 AM
To: [log in to unmask]
Subject: Fwd: Pile Driving Stop Criteria

Dear Mr. Jedari

Regarding your request for termination critieria of steel pile driving in sea bed, please see my comments below:

- For a 32 inch pile to be driven 20 m of depth, my understading is you are using a light hammer. Depending on soil conditions at the construction site and the required capacity, I beleive you would need at least a Delmag-46 or equivalent. That is why you experience high blow counts at times.

- To select the proper hammer, the geotechnical data as well as the design capacities are required. Then the termination criteria could be set, doing the appropriate analyses such as WEAP.

- Also, the driving has to be monitored using pile dymanic test (PDA). The PDA test shall give you the transferred energy of the hammer to the pile, driving stresses, pile integrity (or damage), and most important of all, the pile capacity. Then you can establish a meaningful termination criteria, that is a certain penetration depth or blow count.

Regards,

Kazem Fakharian

--- On Thu, 5/5/11, Hamidreza Sadeghi <[log in to unmask]> wrote:

From: Hamidreza Sadeghi <[log in to unmask]>
Subject: Fwd: Pile Driving Stop Criteria
To: "Dr. Fakharian" <[log in to unmask]>
Date: Thursday, May 5, 2011, 5:06 AM

Dear Prof Fakharian

This a question posed by one of JISC society which I find in accordance with your experiences. If you may like to answer him, please CC reply to [log in to unmask]" rel=nofollow target=_blank>[log in to unmask]

Sincerely,
Hamidreza Sadeghi

---------- Forwarded message ----------
From: Cyrus Jedari <[log in to unmask]" rel=nofollow target=_blank>[log in to unmask]>
Date: Wed, May 4, 2011 at 9:25 PM
Subject: Pile Driving Stop Criteria
To: [log in to unmask]" rel=nofollow target=_blank>[log in to unmask]

Dear colleagues
We are driving some steel piles in the sea shore. the hammer we use is Delmag 33. the lengh of each individual pile is 20 meters with 32 inches Diameter. the number of impact for penetrating of pile for each 30 cm is more than 100 for some Depthes.
I want to know about stop criteria of pile driving. When we should stop driving to avoid the destroying the piles? Unfortunately We can not provide a heavier Hammer. I will appreciate any useful information about this phenomenon.
Regards
Jedari