Group effect for ACIP piles
Group effect for ACIP piles
(OP)
Can anyone provide some info about group effect for ACIP piles w/ spacing 3-6 D, not end bearing (in loose to medium dense sand)? Any reference books, papers (specific title, author if possible)?
I have a couple of papers/manuals that mention reduction factors for drilled piers, but not for ACIP, though similer.
Thanks in advance.
I have a couple of papers/manuals that mention reduction factors for drilled piers, but not for ACIP, though similer.
Thanks in advance.





RE: Group effect for ACIP piles
RE: Group effect for ACIP piles
RE: Group effect for ACIP piles
That said, so much of the performance of ACIP piles depends on the skill of the installer and the soil types. I got no problem being conservative and using a more conservative analysis. Just don't be surprised if any measured settlemet is much less than predicted.
RE: Group effect for ACIP piles
McVay et al. (1994) and O'Neill et al. (2002) has concluded that ACIP piles behave more like drilled shafts in sandy soil than driven piles and the FHWA method for drilled shafts yielded the closest prediction of compression capacity for ACIP piles.
For displacement type auger cast piles I have been involved, such as Berkel's APGD piles and Morris-Shea's DeWaal piles, I found they performed better than regular ACIP piles and most likely behave between drilled shafts and driven piles, from the load tests I observed.
When I posted my question I was hoping to find some specific references for ACIP group effect. I guess there is none.
Rather than analyzing pile group settlement in my case, I will probably just reduce the pile capacity using group efficiency as suggested by FHWA-HI-88-042 drilled shaft manual or CoE TI-88-02 Design of Deep Foundatoins.
RE: Group effect for ACIP piles
Depending on the loadings, the equivalent pier or raft method presented in the Drilled Shaft Manuel might be a better reference with heavy loaded structures and large pile groups.
RE: Group effect for ACIP piles
I agree that group capacity and group settlement are two different issues. They are not related if the total loading on pile cap is given and fixed. But they are related if total loading can be reduced depending on allowable capacity from pile.
I may confused you earlier since I know in my case settlement criteria won't be an issue.
Thanks for your comments, dmoler.