Análise comparativa da capacidade de carga de estacas hélice contínua por meio de provas de carga e por métodos semiempíricos

Abstract

The dimensioning of the elements of a foundation depends on factors related to the structural design as well as those pertinent to the characteristics of the subsoil layers, to which the structural loads will be dissipated. The factors related to the soil are obtained semi-empirically through the information of the report of the Standart PenetrationTest (SPT). Due to the complex and variable structure of the soils and the executive technical variables of the types of foundations, numerous researches and methods of dimensioning were developed over decades, including notorious works proposed by Brazilian engineers and researchers, consecrated worldwide. Among these, the semi-empirical methods of Aoki-Velloso (1976) and Décourt-

Quaresma (1996) stand out. In both sizing methods, safety factors and permissible loads, required and recommended by the Brazilian foundation standard, NBR 6122 (ABNT, 2010), are defined to ensure the integrity and safety of the structure. These safety factors must be evaluated in practice through field tests, called Load Testing, carried out in accordance with NBR 12131 (ABNT, 2006), from the comparison with the permissible load values obtained in the sizing methods. In this sense, the present work of course completion has the objective of evaluating the current safety factors of Continuous Flight Auger Piles of four works in the city of Goiânia, by means of results of Load Testing, evaluating the effectiveness of the methods of dimensioning of AokiVelloso and Décourt- Quaresma, in accordance with the values suggested by norm NBR 6122 (ABNT, 2010). Developed through the use of semiempirical methods cited for the calculation of load capacity and load allowed of piles and follow-up of field Load Tests, the course completion project demonstrated, in the end, that these methods meet the requirements imposed by NBR 6122 (ABNT, 2010), in relation to minimum safety factors, when the Load Test is satisfactory. In this cases, the value of the actual safety factor found was higher than the safety factor of calculation. It was also concluded that the Aoki-Velloso method is more conservative than DécourtQuaresma by providing higher safety factors.