# COMPARATIVE STUDY OF SOIL-STRUCTURE INTERACTION METHODS FOR THE ANALYSIS OF LATERALLY LOADED PILE FOUNDATIONS

## Palavras-chave:

pile foundations, soil-structure interaction, nonlinear analysis, p-y curves## Resumo

When foundations are subjected to significant horizontal loads, as in bridges or offshore

structures, a more in-depth research of the soil-structure interaction is of utmost importance. Different

methods are given to carry out such study, among which the Winkler spring models and continuum

models stand out. This work addresses these methods for the analysis of laterally loaded piles inserted

in clayey and sandy soil. For the discrete spring models, both linear springs with a plasticity criterion

and nonlinear springs defined by given p-y curves are adopted. For the continuum model, the soil

plasticity is described by a Mohr-Coulomb criterion within a finite element method (FEM) approach.

As results, the horizontal displacements of the pile-soil sets are taken and a constant of horizontal

subgrade reaction is estimated, which are compared to results from load tests performed in Brazilian

soils of Campinas-SP and Ilha Solteira-SP. In general, displacements obtained by the analysis methods

were higher than the load tests in the initial elastic part and became smaller at a final yielding phase.

The analysis points to the importance of considering concrete as an elastoplastic material and of

precisely defining the Young’s modulus of concrete and the initial stiffness of the superficial soil.

Among the analysis methods, the linear spring model stands out for its satisfactory results and

simplicity, in terms of appliance and input data. On the other hand, the nonlinear spring and

continuum methods require specific geotechnical tools, but already contemplate iterative load

application, which facilitates the account of concrete’s nonlinearity.