Análise da interação solo-estrutura em edifícios com fundações superficiais a partir do método dos elementos finitos

Abstract

In structural analysis, a very common practice in calculation offices is to carry out projects using the hypothesis of non-displaceable supports, thus disregarding the deformability of the soil, which can lead to active forces and displacements that do not conform to reality. Thus, it is essential to analyze the effects of soil-structure interaction (SSI) during the realization of projects. The analysis of SSI allows models close to reality, simulating the set behavior of structural and geotechnical system. In this paper the variation of the internal forces and the vertical and horizontal displacements of a structure was analyzed when considering the SSI, in buildings where the brazilian standard does not require the consideration of the SSI in the structural analysis, seeking to demonstrate that not considering it can cause misunderstandings in the design; besides checking the influence of different soil typologies and of the number of floors. Therefore, by using SAP 2000 program, two buildings in reinforced concrete with 7 and 14 floors on shallow foundations, supported by two different soil profiles were analysed, with the soil massif being simulated with three-dimensional finite element meshes. The results evidenced stress redistribution in SSI models when compared to models with intercheable supports, being observed a load migration from central to periphal columns, and the higher variations occurring in taller building and in the models with less resistant soil. The variations were also more representative in the first floors of both buildings. As for displacements, an increase in horizontal displacements was noted and, on the other hand, a reduction in differential and distortional settlements in buildings with flexible supports. Thus, it was concluded that by disregarding the deformability and soil action on the structure, the analysis becomes susceptible to less realistic results, showing the importance of using soil-structure interaction to have a more real and safe structural analysis.