Contact US

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!

*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

Driven pile capacity increase with time

Driven pile capacity increase with time

Driven pile capacity increase with time

It might be very basic however would like to ask.
Can someone share some literature or explain the mechanism of how driven pile is gaining more capacity over time like after several days of driving? Is there any way to determine how many minimum days need to wait to do PDA after driving. All I saw usually, it says 3 to 5 days, a few cases a week. Thanks

RE: Driven pile capacity increase with time

Thanks PEinc

RE: Driven pile capacity increase with time

My Short Answer:

Interaction of piling and soil is often represented with springs:

When a pile is driven, soil is "pushed" laterally away from the pile (compressed, like a spring). The soil pushes back (like a spring) against the pile, increasing the friction force between the soil and the pile. Friction force begins to increase shortly after driving stops, rapidly at first, then slowing down (exponential decay, I suppose).

My Long Answer:

Pile drivers make practical use of this concept when extracting previously driven piles:
Drive the existing pile a few inches deeper, then extract the pile. Equipment changeover from driving to extraction has to be made quickly (within a few minutes) since friction will begin noticeably increasing almost immediately.

For displacement piles, like wood or concrete, the effect is enhanced compared to steel piling. The large volume of displacement piles mean the soil is compressed more.

Driving additional displacement piles nearby will tend to compresses soil against piles that are in place - increasing soil-pile contact force.

Wood piles have other characteristics:

1) Wood piles are tapered, a change of about 1" diameter for each 10' of length for Southern Yellow Pine. Soil compression "wedges" the pile in place - at least for settling deeper.

2) Wood piles swell when they get wet (groundwater). Swelling tends to increase the soil-pile contact force.

Waiting 3 to 5 days after driving before testing sounds reasonable. (Probably about 3 to 5 half-lives of exponential decay).


RE: Driven pile capacity increase with time

Only driven piles in clay typically gain strength. This is called “set up”. It’s due to dissipation on pore pressure. You can drive a pile and be getting 80 blows per 0.25, try restive the pile next day and it won’t budge! Get the GRL WEAP handbook

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close