×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Max. depth of 14" auger cast pile

Max. depth of 14" auger cast pile

Max. depth of 14" auger cast pile

(OP)
The IBC states that the maximum length of an auger cast pile is 30 x diameter.   For a 14" diameter pile, that is 35 feet.  (see section 1810.3.2 of the 2006 IBC)

There is an exception to that where the IBC says that if a design professional with knowledge in the field of soil mechanics and pile foundation directly supervises the pile installation and certifies that they were constructed per the plans/documents, then it is OK to extend past the 30d limit.

Is this just a cautionary limit or are there major pitfalls with exceeding the 30d?
 

RE: Max. depth of 14" auger cast pile

16" dia by 50' are common in these environs...

Dik

RE: Max. depth of 14" auger cast pile

That is a cautionary limit. 60d or more seems routine in my part of the world.

RE: Max. depth of 14" auger cast pile

We used some ACIP piles 120 feet long to support a linear accelerator addition to a hospital, They were either 16 or 18 inches in diameter. They went through about 90 feet of loess and into glacial till - pretty ideal conditions. We had to break augers each time to get that depth.

We also used 18-inch ACIP piles 80 feet long in floodplain alluvium - 20 feet of silt and clay underlain by sand. The water table was above 10 feet.

In both cases, the reinforcing was a small cage about 15 feet long, as was common practice at that time and place. No full-length center bar was used, and I doubt if one could have been because the grout tends lose a little water into those formations and get harsh.

RE: Max. depth of 14" auger cast pile

JAE...for consistent strata, there's not an issue with running a 14" dia. ACP to 50 feet or so. I would only be concerned if you had a thick, very soft stratum over a hard bearing layer.

RE: Max. depth of 14" auger cast pile

I've designed (geotech, not structural) ACP piles 16" piles 80 feet long.
I've also observed the installation of piles of the same depth in coastal Georgia.
The biggest problem was getting the 25 foot long cage into the top of the pile after the auger withdrew.

RE: Max. depth of 14" auger cast pile

For the reasonably competent soil that we have, my rebar cage consists of 4-25M by approx 10' long held together by a cage of 10M bars. The length was chosen as a multiple of bars coming from a 12m or 18m length...

Dik

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources