Avaliação do efeito da modificação da ponta na capacidade de carga de estacas escavadas tipo trado mecanizado

Abstract

The civil construction industry is always searching for engineering techniques and procedures that ensure safe work with cost rationalization. In case of projects related to construction of foundations elements, they are usually idealized to obtain the maximum load capacity of them in order to diminish their quantity or size. The present research aimed to evaluate the load capacity of piles constructed by mechanized auger without the use of stabilizers fluids and with different modifications of their tips. In order to achieve this objective, eight piles with a diameter of 15,75 were executed in four different sites, each one with a different soil profile, totalizing 32 piles. Between these eight piles in each site, two were executed in the conventional manner to serve as reference and six piles were executed with some modification on their tips: two had the soil at the bottom compacted, two had an amount of mortar placed at the bottom and mixed with the soil existing there and, to the other two, the mortar placed at the bottom was also compacted The evaluation of the lateral load capacity as function of the time lag between excavation and concrete filling was also done. The mobilized load at the tip and by the lateral surface of the piles were evaluated by dynamic loading tests. Thus, with the results obtained, it was possible to evaluate the effect of type of tip modification at the load capacity, concluding that the technique of placing mortar at the bottom of the pile gives better results than the other methods.