Estudo da variação da tensão admissível com a dimensão de sapatas apoiadas em subsolos arenosos

Abstract

The dimension of the footings is a factor of influence in the calculations of the bearing capacity and predictions of settlements of superficial foundations (for example, footings) on sandy soils. The study of the variation of the allowable stress design with the footings size allows to identify the most economical dimension of the footings for each pillar of the work, and to define the value of the allowable stress and the size of the footings that defines the highest possible allowable stress (B ) for the study case. In this dissertation it is evaluated some theoretical and semi-empirical methods adopted in the literature to predict the bearing capacity and settlements of footings in sandy soils by means of experimental results obtained in the literature, of load tests performed on real footings and plates of different sizes on sandy soils. The value of the deformation modulus of each adopted sublayer of the sandy soil is a determinant factor for the methods of settlements predictions, investigated in this study (Schmertmann, 1970; Schmertmann et al., 1978). It is observed the influence of the adopted correlations between the results of field tests SPT and cone penetration CPT in the predicted settlements. It is concluded that the size of the footing in sandy soils that define the allowable stress design of the shallow foundations analyzed in this study varied from 1.7m to 3.4m, according to the geotechnical parameters and to the adopted model of calculation methods. The higher the value adopted for the deformability module, higher the value of B, and greater is the probability of the rupture to define the allowable stress design.