Bernadete Ragoni Danziger

3-D predictions of installation and group effect on driven piles in sands

Abstract The installation of individual piles driven in sands increases the soil density and the soil strength around the pile, providing generally a beneficial effect toward the pile capacity. The simultaneous effect of pile installation and pile group interaction is generally difficult to predict by the classical pile analysis procedures, although more recent advances in academic and commercial programs for numerical analyses have the potential for providing a better understanding of this complex interaction. In this paper, the simultaneous effects of pile installation and pile group are investigated by 3-D FE analysis, by taking into account the soil densification around an individual driven pile. The finite element program Plaxis 3D Foundation is used to model a documented case study of a small-scale piling group in sands, taking into consideration the initial state of the soil before installation and the soil improvement after driving. The revised and improved parameters of the sand after the installation are used in this paper to model a 9-pile group with different pile spacing, to account for the simultaneous effect of sand densification and pile group. The comparison of the experimental values with those simulated numerically shows reasonably good agreement.

Contribuição das alvenarias na interação solo-estrutura através do estudo de um caso envolvendo danos estruturais

An analysis of soil-structure interaction of a construction with unsatisfactory foundation behavior along time is presented. Previous analyses by Rosa (2005) are briefly described considering soil x structure interaction in predicting foundation settlement. In addition, a new analysis is now presented, including the influence of the masonry in the soil-structure interaction. The predicted distortional settlements are analyzed in conformity with the observed damages documented at various moments of the construction lifetime. Kelvins model was employed to represent the soil behavior along time. Notwithstanding the simplifications adopted and justified in the article, the results of the numerical analysis were able to reproduce the extent and spatial location of the damages. Such results show the relevance of a more realistic foundation analysis involving soil x structure interaction.

Soil-Structure Interaction - Case History Analysis Involving Structural Damage

This thesis presents a case history contemplating a soil x structure interaction analysis of a construction that revealed unsatisfactory foundation performance with time, showing cracks due to excessive distortional settlements. The analysis includes settlement predictions with and without due consideration of soil x structure interaction with the foundation soil. The analyses contain the prediction of settlement development with time, its uniformization tendency, the columns load redistribution and the relevant changes in the stresses of some structure sections. The predicted distortional settlements with and without due consideration of soil x structure interaction were compared and confronted in conformity with the documented structure damages in different periods of the construction life time. The structure has been analysed with aid of a three-dimensional linear elastic FEM model, without considering the rheological deformation of concrete. The Kelvin model has been employed in order to properly represent the soil behaviour with time. It has been found that, notwithstanding the simplifications adopted in the analysis and tentatively justified in various phases of the study, the results obtained in the numerical analysis were capable of duplicating the damages that occurred. The conclusions emphasized the importance of a more real design conception of the structure, including the foundation soil, possible to be implemented with the computational tools available at present.