Single Pile Settlement

[EireChch]

I am looking at three different settlement methods, shown below. The 3rd method is giving settlements approximately 10 times more that the other two. I have just coded the 3rd it into excel and did a hand calc and it seems right. Although it could be a calculation error, i will check thoroughly tomorrow.

In the meantime, I am wondering has anyone else seen a similar trend with this method? Do you use a different method(s)?

1. Fleming, W.G.K. (1992) A new method for single pile settlement for prediction and analysis, Géotechnique, 42(3): 411–425. 2. Piling Engineering, Fleming K, Weltman A, Randolph M and Elson K 3rd Edition 2009, Taylor & Francis.
3. Randolph and Wroth 1979 method - Foundation Analysis and Design, Fifth Edition, Joseph E Bowles, Page 909.

 

[Okiryu]

EireChch, perhaps not the proper answer but I think (and that happened to me several times) that clients do not want to hear about settlement issues if they are paying for piles...I am not saying that piles should always reach bedrock but on the other hand just refer to the Millenium Tower at San Francisco...

 

[ATSE]

I suggest using Fellenius and his "Unified Design"
Dr. Bengt Fellenius articulates the fine points of pile behavior for capacity and settlement in many of his 300+ papers, and in his free RedBook.
He argues for an imaginary raft at the neutral plane - similar to Terzaghi's 2/3 point method.