Nonlinear Finite Element Analysis of Laterally Loaded Piles in Cohesive Sediments

Abstract

Laterally loaded single piles are usually analyzed by methods deriveddirectly from the classical beam on elastic foundation or Winkler soil model. Soilstrength is characterized using modulus of sub-grade reaction.Early solutions that employed Winkler’s model assumed that the modulus ofsub-grade reaction is constant with depth, or linearly varying with depth, whilein fact it varies nonlinearly with depth due to the nonlinear soil response toloads. The characterization of soil using “p-y curves” concept; (which relates thesoil reaction and pile deflection at typical points along its length, and extractedfrom field tests), is proper for representing nonlinearity in soil response, andgives better solutions. Another method used for the solution of the problem oflaterally loaded piles is the elastic continuum method. In this method the soil ismodeled as an elastic media, such formulation poses increased difficulty whenthe soil modulus varies with depth.The Sub-grade Reaction or Winkler method of solution is used through thisstudy. The soil is characterized by a nonlinear springs with employing the “p-y”model, while the pile is modeled as a two-node element.