Report No.: CCEER-99-8

Title: Refinement of the Strain Wedge Model Program (Manual)

Authors: Mohamed Ashour and Gary Norris

Date: September, 1999

Sponsoring Agency: State of California Department of Transportation (Caltrans)

Performing Organization:
Department of Civil Engineering/258
University of Nevada, Reno
Reno, NV 89557


This report describes the computer program of the strain wedge model, a program that characterizes the behavior of single piles, pile groups, and pile caps embedded in uniform or layered soils when subjected to lateral loads. The computer program presented in this report is based on the concepts of the strain wedge model which have been published and reported to Caltrans in a separate report.

The characterization of lateral load behavior associated with single piles and pile groups embedded in uniform or layered soils can be accomplished using the strain wedge model. The strain wedge model for laterally loaded pile behavior is a new predictive method which relates the stress-strain behavior of soil in the developing three-dimensional passive wedge in front of the pile (denoted as the strain wedge) under lateral load to the one-dimensional beam-on-elastic foundation parameters commonly employed in "p-y" curve analyses.

The strain wedge model has been developed to analyze individual piles, or a square or rectangular pile group with its associated pile cap, under lateral loading. The strain wedge model can account for both free- and fixed-head conditions, and uniform or layered soil conditions. The strain wedge model also has the ability to predict the working pile head load of a single pile and/or that of each pile in a group, the working load associated with a pile cap, the pile head deflection, the maximum bending moment for a single pile or each pile in a group, and p-y curves for a single pile. (by authors)