This paper presents information on design analyses of large diameter piles using
conventional p-y curves as recommended by the American Petroleum Institute
(API RP2A, 1993). API RP2A adopted the soft clay criterion developed by
Matlock (Matlock, 1970) based on 12.75-inch piles. API RP2A also adopted the
API sand criteria originally introduced by Reese, Cox, and Koop (Reese et. al.,
1974) based on 24-inch piles. Since Matlock and Reese published their original
papers, there have been several publications recommending changes to their p-y
criteria, especially regarding the need to adjust the Matlock p-y curves for pile
diameter effects. The following sections attempt to clarify the issue of diameter
effects on p-y curves.
Author: Ignatius P.O. Lam, Earth Mechanics, Inc.
Publisher: DFI