Capacidade de carga de fundações submetidas a esforços verticais de tração

Abstract

Foundations Submitted to Pullout Forces constitute a quite recent theme of Soil Mechanics; the principal researches have been developed since the early 60 decade. A great number of load tests - especially conducted for an important transmission line foundation project - have been performed on footings and piers, permitting the comparison of the application of the principal theories to residual gneiss. These load tests have also been made possible a series of observations concerning the pulled out foundations. Particular emphasis is given to the load tests procedures and to the geotechnical characterization presentation of the test site.Test results documentation are extensively given. As the tests basic characteristic, it was observed a pattern of behaviour with very small displacements not only for the footings but also for the piers, even approximating the well effectively characterized failure. Load cycles, load velocity applications, observed failure surfaces are some of the aspects analysed throughout the work. Concerning the application of the various calculus rnethodology to the footings and piers tested, the minor premises of the different calculus procedures are extensively discussed and detailed. Adaptations and modifications are introduced for footings, in order to conveniently adequate the calculus methodology to the test conditions. Such adaptations and modifications have showed acceptable results for the variety of modern methods and sometimes excelent ones. For piers, only the Grenoble University Method have presented applicable calculus methodology, providing good estimates.