Nonlinear Seismic Response Of Single Piles

Abstract

In this paper, a method is proposed to analyse the seismic response of single piles under nonlinear soil condition. It is based on the Winkler foundation model formulated in the time domain, which makes use of p-y curves described by the Ramberg-Osgood relationship. The analyses are performed referring to a pile embedded in two-layer soil profiles with different sharp stiffness contrast. Italian seismic records are used as input motion. The calculated bending moments in the pile are compared to those obtained using other theoretical solutions.

Evaluation of kinematic bending moments in a pile foundation using the finite element approach

“…The kinematic interaction has been studied with various models, such as: i) simplified models with the hypothesis that the pile follow the motion of soil in free-field condition (Margason [8]; Margason and Halloway [9]; NEHRP [10]); ii) Winkler models (BDWF), which summarizes the soil-pile interaction, with a system of springs and dampers distributed along the pile and a linear-elastic (Dobry and O'Rourke [11]; Nikolaou et al [12]; Mylonakis [5]; Nikolaou et al [13]; Sica et al [14]; Castelli et al [15]), or non-linear and hysteretic soil behaviour (Conte and Dente, [16,17], Castelli and Maugeri [18]; Maiorano et al, [19]; Cairo et al [20]); iii) FEM or BEM models (Wu and Finn [21], Maiorano and Aversa [4]). In particular, some Winkler models (BDWF) provide fairly simple formulas to be used for determining the maximum kinematic moment at the interface between two soil layers with different stiffnesses (Dobry and O'Rourke [11]; Nikolaou et al [12]; Mylonakis [5]; Nikolaou et al [13]).…”