Análise da confiabilidade de fundações por estacas do tipo hélice contínua, franki e pré-moldada

Abstract

In Brazil, it is common for foundation projects to be elaborated using a prescriptive methodology, so as not to directly consider the uncertainties inherent to the problem. The disregard for the variability of the variables involved in the dimensioning can have serious consequences, not only in terms of the economic nature of the work, but mainly in the service limit state and useful limit state, when not, in the lives, in the vicinity of the building. A solution to this problem may be the use of reliability tools, responsible for quantifying structural safety through the probability of failure during the stages of the elaboration of the foundation project. Therefore, in this work the prediction of the probability of failure of the foundation of a building of 14 floors is made, using the methodology developed by Aoki and Velloso (1975) with the same name and considering three types of stakes: Franki, continuous helix and precast. The results are subsequently validated by the FORM (First Order Reliability Method) and Monte Carlo reliability methods. Prediction of the probability of failure of the foundation is also made by varying the diameters of the stakes. It was observed that for the diameters of 30 and 40 cm the type of stake that presented the best reliability was the continuous helix, followed by the precast and Franki. However, when considering piles with a diameter of 50 cm, the best reliability was the continuous helix, followed by Franki and precast. Finally, this work exemplifies the importance and practicality of considering the uncertainties involved in the projects of the elements of foundations.