Member Login

Remember Me
Forgot Password?
Join Us!

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!

Join Eng-Tips
*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.

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

Pile Edge Distance To Pile Cap

Pile Edge Distance To Pile Cap

The edge distance from the edge of a pile to the edge of the pile cap is determined by the punching shear from the pile. I have a round augur cast pile that if it is placed on the exact edge of the pile cap on the two sides at the corner it will not create a problem with punching shear within the pile cap.   

The CRSI has minimum critera that defines the minimum edge distance from the edge of a pile to the edge of the pile cap. CRSI does not explain where and why this criteria was established.

Over the years I see that many designers place piles closer then the minimum edge distance as defined by CRSI.

My question is what is the REAL minimum edge distance requirement for piles and what defines the minimum edge distance if punching shear doesn't control?  Is it a constructablilty issue?

Any insite to this would be well appreciated.  


RE: Pile Edge Distance To Pile Cap

That's a good question, and I don't know the answer, but do have an opinion:

1. As you have suggested, constructibility. With a plus or minus 3" tolerance allowed by many specs on pile location, some "wiggle room" is needed to make sure the cap can be constructed exactly at the planned location even if the piling are off a little. And...

2. If the pile cap is underground, the protective rebar cover is, of course, 3 inches. To guarantee that the rebar mat completely covers the top of the pile, the edge of the pile cannot be any closer than 3" to the edge of concrete. I prefer to have the mat completely cover the the pile top to make absolutely certain that no (vertical) load can be applied to rebar "cover" concrete.

Add these two reasons together, and you get a minimum theoretical clearance of 6" between edge of pile cap and edge of pile.

Again, I don't know if any of this is true, but it seems a reasonable thing to do. idea r2d2

RE: Pile Edge Distance To Pile Cap

CRSI says: "To prevent vertical edge splitting, minimum edge distance, E, to center of piles is 15 inches for pile capacity (P)< 60 tons, 21 inches for 60< (P) <120, 27 inches for 120 < (P) <200 and 30 inches for P > 200 tons."  

RE: Pile Edge Distance To Pile Cap

agree with civilperson... I've used the CRSI edge distances as a minimum on my previous ACP designs.   

RE: Pile Edge Distance To Pile Cap

I just delved into the strut and tie design for a shearwall pilecap.  However, a typical pilecap is very similar in design.  Most pilecaps are designed using the strut and tie method because of the efficiency of design and the increased accuraccy of the load path.

That being said, the bottom steel needs to be developed past the inside face of the pile.  This is where the critical tension section is located.  To obtain the appropriate embedment of the reinforcement, a hook is supplied at the end of the rebar and the additional embedment length (ldh, see ACI 12.5.2) is supplied.  Many times this dictates the minimum pile cover.

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!


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