From: "Brian K. Smith" <smitheng(--nospam--at)dos.net>
Date: Fri, 14 May 1999 09:03:35 -0500
This subject is discussed in detail, with an example, in "Foundation
Analysis and Design" by Bowles, 4th Edition. I have actually used his FEM
program written in Fortran to analyze some small timber piles a number of
years ago. If I remember correctly, you use the projected area of the pile
and double the stiffness of the springs to account for side friction. There
are also a number of additional "things" to take into consideration. Such
as the springs should be (in my opinion) one way springs; however, you need
springs on both sides of the pile because it will try to form a lazy "S"
shape below grade. Also, you need to be able to limit or at least check the
forces imposed by the springs because there will be an upper bound limit at
which the spring essentially fails. You may try to get a copy of the fifth
edition of this book.
Brian K. Smith, P.E.
Bossier City, Louisiana
> This is what we are trying, I question how we should deal with the curved
> surface of the round pile. Should all the spring stiff. be the
> same considering
> the horiz. projected area of the pile or should the spring stiff.
> be reduced as
> you travel around the 1/2 circumf. of the pile?