OasisLMS

Abstract: The bidirectional load test emerges as an excellent alternative for large-diameter piles subjected to high loads. This is because, by dividing the pile into two segments (upper and lower) and allowing them to react against each other, there is no need to construct a robust reaction system to support such loads. This enables significant advantages in terms of safety and economy when compared to conventional load tests. However, advancements in this methodology have made tests increasingly cost-effective, allowing their application even to small-diameter piles. Bidirectional tests on such structures are essential for understanding their mechanical behavior and establishing their equivalence with the results of conventional load tests, a common practice in the interpretation of these results. Nevertheless, there are few published cases of bidirectional load tests on this type of pile. Additionally, the use of this testing method in non-conventional soils, such as tropical soils, remains underexplored in the literature. The present study investigates a case study involving five small-diameter Continuous Flight Auger (CFA) piles tested using the bidirectional method in tropical soil from Basí lia region, Federal District, Brazil. The local subsoil primarily consists of residual lateritic soil, typical of tropical regions. The piles had a diameter of 0.50 m and lengths ranging from 14 to 19 m, with the position of the expansive cell assembly varying between 2 and 4 m from the pile tip. Three out of the five piles exhibited significant displacements in both segments, while the other two required extrapolation of load-settlement curves. The results were analyzed using different extrapolation methods, failure criteria, and construction of equivalent load-settlement curves, allowing for the evaluation of the influence of construction variables on the behavior and determination of the ultimate load for each pile.

Dr. Yuri Barbosa; Alysson Santos Resende

Annual Conference Proceedings