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

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.